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| author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
| commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
| tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /Documentation/i2c | |
| download | linux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz linux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.bz2 linux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.zip | |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'Documentation/i2c')
32 files changed, 3138 insertions, 0 deletions
diff --git a/Documentation/i2c/busses/i2c-ali1535 b/Documentation/i2c/busses/i2c-ali1535 new file mode 100644 index 000000000000..0db3b4c74ad1 --- /dev/null +++ b/Documentation/i2c/busses/i2c-ali1535 @@ -0,0 +1,42 @@ +Kernel driver i2c-ali1535 + +Supported adapters: + * Acer Labs, Inc. ALI 1535 (south bridge) + Datasheet: Now under NDA + http://www.ali.com.tw/eng/support/datasheet_request.php + +Authors: + Frodo Looijaard <frodol@dds.nl>, + Philip Edelbrock <phil@netroedge.com>, + Mark D. Studebaker <mdsxyz123@yahoo.com>, + Dan Eaton <dan.eaton@rocketlogix.com>, + Stephen Rousset<stephen.rousset@rocketlogix.com> + +Description +----------- + +This is the driver for the SMB Host controller on Acer Labs Inc. (ALI) +M1535 South Bridge. + +The M1535 is a South bridge for portable systems. It is very similar to the +M15x3 South bridges also produced by Acer Labs Inc. Some of the registers +within the part have moved and some have been redefined slightly. +Additionally, the sequencing of the SMBus transactions has been modified to +be more consistent with the sequencing recommended by the manufacturer and +observed through testing. These changes are reflected in this driver and +can be identified by comparing this driver to the i2c-ali15x3 driver. For +an overview of these chips see http://www.acerlabs.com + +The SMB controller is part of the M7101 device, which is an ACPI-compliant +Power Management Unit (PMU). + +The whole M7101 device has to be enabled for the SMB to work. You can't +just enable the SMB alone. The SMB and the ACPI have separate I/O spaces. +We make sure that the SMB is enabled. We leave the ACPI alone. + + +Features +-------- + +This driver controls the SMB Host only. This driver does not use +interrupts. diff --git a/Documentation/i2c/busses/i2c-ali1563 b/Documentation/i2c/busses/i2c-ali1563 new file mode 100644 index 000000000000..99ad4b9bcc32 --- /dev/null +++ b/Documentation/i2c/busses/i2c-ali1563 @@ -0,0 +1,27 @@ +Kernel driver i2c-ali1563 + +Supported adapters: + * Acer Labs, Inc. ALI 1563 (south bridge) + Datasheet: Now under NDA + http://www.ali.com.tw/eng/support/datasheet_request.php + +Author: Patrick Mochel <mochel@digitalimplant.org> + +Description +----------- + +This is the driver for the SMB Host controller on Acer Labs Inc. (ALI) +M1563 South Bridge. + +For an overview of these chips see http://www.acerlabs.com + +The M1563 southbridge is deceptively similar to the M1533, with a few +notable exceptions. One of those happens to be the fact they upgraded the +i2c core to be SMBus 2.0 compliant, and happens to be almost identical to +the i2c controller found in the Intel 801 south bridges. + +Features +-------- + +This driver controls the SMB Host only. This driver does not use +interrupts. diff --git a/Documentation/i2c/busses/i2c-ali15x3 b/Documentation/i2c/busses/i2c-ali15x3 new file mode 100644 index 000000000000..ff28d381bebe --- /dev/null +++ b/Documentation/i2c/busses/i2c-ali15x3 @@ -0,0 +1,112 @@ +Kernel driver i2c-ali15x3 + +Supported adapters: + * Acer Labs, Inc. ALI 1533 and 1543C (south bridge) + Datasheet: Now under NDA + http://www.ali.com.tw/eng/support/datasheet_request.php + +Authors: + Frodo Looijaard <frodol@dds.nl>, + Philip Edelbrock <phil@netroedge.com>, + Mark D. Studebaker <mdsxyz123@yahoo.com> + +Module Parameters +----------------- + +* force_addr: int + Initialize the base address of the i2c controller + + +Notes +----- + +The force_addr parameter is useful for boards that don't set the address in +the BIOS. Does not do a PCI force; the device must still be present in +lspci. Don't use this unless the driver complains that the base address is +not set. + +Example: 'modprobe i2c-ali15x3 force_addr=0xe800' + +SMBus periodically hangs on ASUS P5A motherboards and can only be cleared +by a power cycle. Cause unknown (see Issues below). + + +Description +----------- + +This is the driver for the SMB Host controller on Acer Labs Inc. (ALI) +M1541 and M1543C South Bridges. + +The M1543C is a South bridge for desktop systems. +The M1541 is a South bridge for portable systems. +They are part of the following ALI chipsets: + + * "Aladdin Pro 2" includes the M1621 Slot 1 North bridge with AGP and + 100MHz CPU Front Side bus + * "Aladdin V" includes the M1541 Socket 7 North bridge with AGP and 100MHz + CPU Front Side bus + Some Aladdin V motherboards: + Asus P5A + Atrend ATC-5220 + BCM/GVC VP1541 + Biostar M5ALA + Gigabyte GA-5AX (** Generally doesn't work because the BIOS doesn't + enable the 7101 device! **) + Iwill XA100 Plus + Micronics C200 + Microstar (MSI) MS-5169 + + * "Aladdin IV" includes the M1541 Socket 7 North bridge + with host bus up to 83.3 MHz. + +For an overview of these chips see http://www.acerlabs.com. At this time the +full data sheets on the web site are password protected, however if you +contact the ALI office in San Jose they may give you the password. + +The M1533/M1543C devices appear as FOUR separate devices on the PCI bus. An +output of lspci will show something similar to the following: + + 00:02.0 USB Controller: Acer Laboratories Inc. M5237 (rev 03) + 00:03.0 Bridge: Acer Laboratories Inc. M7101 <= THIS IS THE ONE WE NEED + 00:07.0 ISA bridge: Acer Laboratories Inc. M1533 (rev c3) + 00:0f.0 IDE interface: Acer Laboratories Inc. M5229 (rev c1) + +** IMPORTANT ** +** If you have a M1533 or M1543C on the board and you get +** "ali15x3: Error: Can't detect ali15x3!" +** then run lspci. +** If you see the 1533 and 5229 devices but NOT the 7101 device, +** then you must enable ACPI, the PMU, SMB, or something similar +** in the BIOS. +** The driver won't work if it can't find the M7101 device. + +The SMB controller is part of the M7101 device, which is an ACPI-compliant +Power Management Unit (PMU). + +The whole M7101 device has to be enabled for the SMB to work. You can't +just enable the SMB alone. The SMB and the ACPI have separate I/O spaces. +We make sure that the SMB is enabled. We leave the ACPI alone. + +Features +-------- + +This driver controls the SMB Host only. The SMB Slave +controller on the M15X3 is not enabled. This driver does not use +interrupts. + + +Issues +------ + +This driver requests the I/O space for only the SMB +registers. It doesn't use the ACPI region. + +On the ASUS P5A motherboard, there are several reports that +the SMBus will hang and this can only be resolved by +powering off the computer. It appears to be worse when the board +gets hot, for example under heavy CPU load, or in the summer. +There may be electrical problems on this board. +On the P5A, the W83781D sensor chip is on both the ISA and +SMBus. Therefore the SMBus hangs can generally be avoided +by accessing the W83781D on the ISA bus only. + diff --git a/Documentation/i2c/busses/i2c-amd756 b/Documentation/i2c/busses/i2c-amd756 new file mode 100644 index 000000000000..67f30874d0bf --- /dev/null +++ b/Documentation/i2c/busses/i2c-amd756 @@ -0,0 +1,25 @@ +Kernel driver i2c-amd756 + +Supported adapters: + * AMD 756 + * AMD 766 + * AMD 768 + * AMD 8111 + Datasheets: Publicly available on AMD website + + * nVidia nForce + Datasheet: Unavailable + +Authors: + Frodo Looijaard <frodol@dds.nl>, + Philip Edelbrock <phil@netroedge.com> + +Description +----------- + +This driver supports the AMD 756, 766, 768 and 8111 Peripheral Bus +Controllers, and the nVidia nForce. + +Note that for the 8111, there are two SMBus adapters. The SMBus 1.0 adapter +is supported by this driver, and the SMBus 2.0 adapter is supported by the +i2c-amd8111 driver. diff --git a/Documentation/i2c/busses/i2c-amd8111 b/Documentation/i2c/busses/i2c-amd8111 new file mode 100644 index 000000000000..db294ee7455a --- /dev/null +++ b/Documentation/i2c/busses/i2c-amd8111 @@ -0,0 +1,41 @@ +Kernel driver i2c-adm8111 + +Supported adapters: + * AMD-8111 SMBus 2.0 PCI interface + +Datasheets: + AMD datasheet not yet available, but almost everything can be found + in publically available ACPI 2.0 specification, which the adapter + follows. + +Author: Vojtech Pavlik <vojtech@suse.cz> + +Description +----------- + +If you see something like this: + +00:07.2 SMBus: Advanced Micro Devices [AMD] AMD-8111 SMBus 2.0 (rev 02) + Subsystem: Advanced Micro Devices [AMD] AMD-8111 SMBus 2.0 + Flags: medium devsel, IRQ 19 + I/O ports at d400 [size=32] + +in your 'lspci -v', then this driver is for your chipset. + +Process Call Support +-------------------- + +Supported. + +SMBus 2.0 Support +----------------- + +Supported. Both PEC and block process call support is implemented. Slave +mode or host notification are not yet implemented. + +Notes +----- + +Note that for the 8111, there are two SMBus adapters. The SMBus 2.0 adapter +is supported by this driver, and the SMBus 1.0 adapter is supported by the +i2c-amd756 driver. diff --git a/Documentation/i2c/busses/i2c-i801 b/Documentation/i2c/busses/i2c-i801 new file mode 100644 index 000000000000..fd4b2712d570 --- /dev/null +++ b/Documentation/i2c/busses/i2c-i801 @@ -0,0 +1,80 @@ +Kernel driver i2c-i801 + +Supported adapters: + * Intel 82801AA and 82801AB (ICH and ICH0 - part of the + '810' and '810E' chipsets) + * Intel 82801BA (ICH2 - part of the '815E' chipset) + * Intel 82801CA/CAM (ICH3) + * Intel 82801DB (ICH4) (HW PEC supported, 32 byte buffer not supported) + * Intel 82801EB/ER (ICH5) (HW PEC supported, 32 byte buffer not supported) + * Intel 6300ESB + * Intel 82801FB/FR/FW/FRW (ICH6) + * Intel ICH7 + Datasheets: Publicly available at the Intel website + +Authors: + Frodo Looijaard <frodol@dds.nl>, + Philip Edelbrock <phil@netroedge.com>, + Mark Studebaker <mdsxyz123@yahoo.com> + + +Module Parameters +----------------- + +* force_addr: int + Forcibly enable the ICH at the given address. EXTREMELY DANGEROUS! + + +Description +----------- + +The ICH (properly known as the 82801AA), ICH0 (82801AB), ICH2 (82801BA), +ICH3 (82801CA/CAM) and later devices are Intel chips that are a part of +Intel's '810' chipset for Celeron-based PCs, '810E' chipset for +Pentium-based PCs, '815E' chipset, and others. + +The ICH chips contain at least SEVEN separate PCI functions in TWO logical +PCI devices. An output of lspci will show something similar to the +following: + + 00:1e.0 PCI bridge: Intel Corporation: Unknown device 2418 (rev 01) + 00:1f.0 ISA bridge: Intel Corporation: Unknown device 2410 (rev 01) + 00:1f.1 IDE interface: Intel Corporation: Unknown device 2411 (rev 01) + 00:1f.2 USB Controller: Intel Corporation: Unknown device 2412 (rev 01) + 00:1f.3 Unknown class [0c05]: Intel Corporation: Unknown device 2413 (rev 01) + +The SMBus controller is function 3 in device 1f. Class 0c05 is SMBus Serial +Controller. + +If you do NOT see the 24x3 device at function 3, and you can't figure out +any way in the BIOS to enable it, + +The ICH chips are quite similar to Intel's PIIX4 chip, at least in the +SMBus controller. + +See the file i2c-piix4 for some additional information. + + +Process Call Support +-------------------- + +Not supported. + + +I2C Block Read Support +---------------------- + +Not supported at the moment. + + +SMBus 2.0 Support +----------------- + +The 82801DB (ICH4) and later chips support several SMBus 2.0 features. + +********************** +The lm_sensors project gratefully acknowledges the support of Texas +Instruments in the initial development of this driver. + +The lm_sensors project gratefully acknowledges the support of Intel in the +development of SMBus 2.0 / ICH4 features of this driver. diff --git a/Documentation/i2c/busses/i2c-i810 b/Documentation/i2c/busses/i2c-i810 new file mode 100644 index 000000000000..0544eb332887 --- /dev/null +++ b/Documentation/i2c/busses/i2c-i810 @@ -0,0 +1,46 @@ +Kernel driver i2c-i810 + +Supported adapters: + * Intel 82810, 82810-DC100, 82810E, and 82815 (GMCH) + +Authors: + Frodo Looijaard <frodol@dds.nl>, + Philip Edelbrock <phil@netroedge.com>, + Kyösti Mälkki <kmalkki@cc.hut.fi>, + Ralph Metzler <rjkm@thp.uni-koeln.de>, + Mark D. Studebaker <mdsxyz123@yahoo.com> + +Main contact: Mark Studebaker <mdsxyz123@yahoo.com> + +Description +----------- + +WARNING: If you have an '810' or '815' motherboard, your standard I2C +temperature sensors are most likely on the 801's I2C bus. You want the +i2c-i801 driver for those, not this driver. + +Now for the i2c-i810... + +The GMCH chip contains two I2C interfaces. + +The first interface is used for DDC (Data Display Channel) which is a +serial channel through the VGA monitor connector to a DDC-compliant +monitor. This interface is defined by the Video Electronics Standards +Association (VESA). The standards are available for purchase at +http://www.vesa.org . + +The second interface is a general-purpose I2C bus. It may be connected to a +TV-out chip such as the BT869 or possibly to a digital flat-panel display. + +Features +-------- + +Both busses use the i2c-algo-bit driver for 'bit banging' +and support for specific transactions is provided by i2c-algo-bit. + +Issues +------ + +If you enable bus testing in i2c-algo-bit (insmod i2c-algo-bit bit_test=1), +the test may fail; if so, the i2c-i810 driver won't be inserted. However, +we think this has been fixed. diff --git a/Documentation/i2c/busses/i2c-nforce2 b/Documentation/i2c/busses/i2c-nforce2 new file mode 100644 index 000000000000..e379e182e64f --- /dev/null +++ b/Documentation/i2c/busses/i2c-nforce2 @@ -0,0 +1,41 @@ +Kernel driver i2c-nforce2 + +Supported adapters: + * nForce2 MCP 10de:0064 + * nForce2 Ultra 400 MCP 10de:0084 + * nForce3 Pro150 MCP 10de:00D4 + * nForce3 250Gb MCP 10de:00E4 + * nForce4 MCP 10de:0052 + +Datasheet: not publically available, but seems to be similar to the + AMD-8111 SMBus 2.0 adapter. + +Authors: + Hans-Frieder Vogt <hfvogt@arcor.de>, + Thomas Leibold <thomas@plx.com>, + Patrick Dreker <patrick@dreker.de> + +Description +----------- + +i2c-nforce2 is a driver for the SMBuses included in the nVidia nForce2 MCP. + +If your 'lspci -v' listing shows something like the following, + +00:01.1 SMBus: nVidia Corporation: Unknown device 0064 (rev a2) + Subsystem: Asustek Computer, Inc.: Unknown device 0c11 + Flags: 66Mhz, fast devsel, IRQ 5 + I/O ports at c000 [size=32] + Capabilities: <available only to root> + +then this driver should support the SMBuses of your motherboard. + + +Notes +----- + +The SMBus adapter in the nForce2 chipset seems to be very similar to the +SMBus 2.0 adapter in the AMD-8111 southbridge. However, I could only get +the driver to work with direct I/O access, which is different to the EC +interface of the AMD-8111. Tested on Asus A7N8X. The ACPI DSDT table of the +Asus A7N8X lists two SMBuses, both of which are supported by this driver. diff --git a/Documentation/i2c/busses/i2c-parport b/Documentation/i2c/busses/i2c-parport new file mode 100644 index 000000000000..9f1d0082da18 --- /dev/null +++ b/Documentation/i2c/busses/i2c-parport @@ -0,0 +1,154 @@ +Kernel driver i2c-parport + +Author: Jean Delvare <khali@linux-fr.org> + +This is a unified driver for several i2c-over-parallel-port adapters, +such as the ones made by Philips, Velleman or ELV. This driver is +meant as a replacement for the older, individual drivers: + * i2c-philips-par + * i2c-elv + * i2c-velleman + * video/i2c-parport (NOT the same as this one, dedicated to home brew + teletext adapters) + +It currently supports the following devices: + * Philips adapter + * home brew teletext adapter + * Velleman K8000 adapter + * ELV adapter + * Analog Devices evaluation boards (ADM1025, ADM1030, ADM1031, ADM1032) + +These devices use different pinout configurations, so you have to tell +the driver what you have, using the type module parameter. There is no +way to autodetect the devices. Support for different pinout configurations +can be easily added when needed. + + +Building your own adapter +------------------------- + +If you want to build you own i2c-over-parallel-port adapter, here is +a sample electronics schema (credits go to Sylvain Munaut): + +Device PC +Side ___________________Vdd (+) Side + | | | + --- --- --- + | | | | | | + |R| |R| |R| + | | | | | | + --- --- --- + | | | + | | /| | +SCL ----------x--------o |-----------x------------------- pin 2 + | \| | | + | | | + | |\ | | +SDA ----------x----x---| o---x--------------------------- pin 13 + | |/ | + | | + | /| | + ---------o |----------------x-------------- pin 3 + \| | | + | | + --- --- + | | | | + |R| |R| + | | | | + --- --- + | | + ### ### + GND GND + +Remarks: + - This is the exact pinout and electronics used on the Analog Devices + evaluation boards. + /| + - All inverters -o |- must be 74HC05, they must be open collector output. + \| + - All resitors are 10k. + - Pins 18-25 of the parallel port connected to GND. + - Pins 4-9 (D2-D7) could be used as VDD is the driver drives them high. + The ADM1032 evaluation board uses D4-D7. Beware that the amount of + current you can draw from the parallel port is limited. Also note that + all connected lines MUST BE driven at the same state, else you'll short + circuit the output buffers! So plugging the I2C adapter after loading + the i2c-parport module might be a good safety since data line state + prior to init may be unknown. + - This is 5V! + - Obviously you cannot read SCL (so it's not really standard-compliant). + Pretty easy to add, just copy the SDA part and use another input pin. + That would give (ELV compatible pinout): + + +Device PC +Side ______________________________Vdd (+) Side + | | | | + --- --- --- --- + | | | | | | | | + |R| |R| |R| |R| + | | | | | | | | + --- --- --- --- + | | | | + | | |\ | | +SCL ----------x--------x--| o---x------------------------ pin 15 + | | |/ | + | | | + | | /| | + | ---o |-------------x-------------- pin 2 + | \| | | + | | | + | | | + | |\ | | +SDA ---------------x---x--| o--------x------------------- pin 10 + | |/ | + | | + | /| | + ---o |------------------x--------- pin 3 + \| | | + | | + --- --- + | | | | + |R| |R| + | | | | + --- --- + | | + ### ### + GND GND + + +If possible, you should use the same pinout configuration as existing +adapters do, so you won't even have to change the code. + + +Similar (but different) drivers +------------------------------- + +This driver is NOT the same as the i2c-pport driver found in the i2c +package. The i2c-pport driver makes use of modern parallel port features so +that you don't need additional electronics. It has other restrictions +however, and was not ported to Linux 2.6 (yet). + +This driver is also NOT the same as the i2c-pcf-epp driver found in the +lm_sensors package. The i2c-pcf-epp driver doesn't use the parallel port as +an I2C bus directly. Instead, it uses it to control an external I2C bus +master. That driver was not ported to Linux 2.6 (yet) either. + + +Legacy documentation for Velleman adapter +----------------------------------------- + +Useful links: +Velleman http://www.velleman.be/ +Velleman K8000 Howto http://howto.htlw16.ac.at/k8000-howto.html + +The project has lead to new libs for the Velleman K8000 and K8005: + LIBK8000 v1.99.1 and LIBK8005 v0.21 +With these libs, you can control the K8000 interface card and the K8005 +stepper motor card with the simple commands which are in the original +Velleman software, like SetIOchannel, ReadADchannel, SendStepCCWFull and +many more, using /dev/velleman. + http://home.wanadoo.nl/hihihi/libk8000.htm + http://home.wanadoo.nl/hihihi/libk8005.htm + http://struyve.mine.nu:8080/index.php?block=k8000 + http://sourceforge.net/projects/libk8005/ diff --git a/Documentation/i2c/busses/i2c-parport-light b/Documentation/i2c/busses/i2c-parport-light new file mode 100644 index 000000000000..287436478520 --- /dev/null +++ b/Documentation/i2c/busses/i2c-parport-light @@ -0,0 +1,11 @@ +Kernel driver i2c-parport-light + +Author: Jean Delvare <khali@linux-fr.org> + +This driver is a light version of i2c-parport. It doesn't depend +on the parport driver, and uses direct I/O access instead. This might be +prefered on embedded systems where wasting memory for the clean but heavy +parport handling is not an option. The drawback is a reduced portability +and the impossibility to daisy-chain other parallel port devices. + +Please see i2c-parport for documentation. diff --git a/Documentation/i2c/busses/i2c-pca-isa b/Documentation/i2c/busses/i2c-pca-isa new file mode 100644 index 000000000000..6fc8f4c27c3c --- /dev/null +++ b/Documentation/i2c/busses/i2c-pca-isa @@ -0,0 +1,23 @@ +Kernel driver i2c-pca-isa + +Supported adapters: +This driver supports ISA boards using the Philips PCA 9564 +Parallel bus to I2C bus controller + +Author: Ian Campbell <icampbell@arcom.com>, Arcom Control Systems + +Module Parameters +----------------- + +* base int + I/O base address +* irq int + IRQ interrupt +* clock int + Clock rate as described in table 1 of PCA9564 datasheet + +Description +----------- + +This driver supports ISA boards using the Philips PCA 9564 +Parallel bus to I2C bus controller diff --git a/Documentation/i2c/busses/i2c-piix4 b/Documentation/i2c/busses/i2c-piix4 new file mode 100644 index 000000000000..856b4b8b962c --- /dev/null +++ b/Documentation/i2c/busses/i2c-piix4 @@ -0,0 +1,72 @@ +Kernel driver i2c-piix4 + +Supported adapters: + * Intel 82371AB PIIX4 and PIIX4E + * Intel 82443MX (440MX) + Datasheet: Publicly available at the Intel website + * ServerWorks OSB4, CSB5 and CSB6 southbridges + Datasheet: Only available via NDA from ServerWorks + * Standard Microsystems (SMSC) SLC90E66 (Victory66) southbridge + Datasheet: Publicly available at the SMSC website http://www.smsc.com + +Authors: + Frodo Looijaard <frodol@dds.nl> + Philip Edelbrock <phil@netroedge.com> + + +Module Parameters +----------------- + +* force: int + Forcibly enable the PIIX4. DANGEROUS! +* force_addr: int + Forcibly enable the PIIX4 at the given address. EXTREMELY DANGEROUS! +* fix_hstcfg: int + Fix config register. Needed on some boards (Force CPCI735). + + +Description +----------- + +The PIIX4 (properly known as the 82371AB) is an Intel chip with a lot of +functionality. Among other things, it implements the PCI bus. One of its +minor functions is implementing a System Management Bus. This is a true +SMBus - you can not access it on I2C levels. The good news is that it +natively understands SMBus commands and you do not have to worry about +timing problems. The bad news is that non-SMBus devices connected to it can +confuse it mightily. Yes, this is known to happen... + +Do 'lspci -v' and see whether it contains an entry like this: + +0000:00:02.3 Bridge: Intel Corp. 82371AB/EB/MB PIIX4 ACPI (rev 02) + Flags: medium devsel, IRQ 9 + +Bus and device numbers may differ, but the function number must be +identical (like many PCI devices, the PIIX4 incorporates a number of +different 'functions', which can be considered as separate devices). If you +find such an entry, you have a PIIX4 SMBus controller. + +On some computers (most notably, some Dells), the SMBus is disabled by +default. If you use the insmod parameter 'force=1', the kernel module will +try to enable it. THIS IS VERY DANGEROUS! If the BIOS did not set up a +correct address for this module, you could get in big trouble (read: +crashes, data corruption, etc.). Try this only as a last resort (try BIOS +updates first, for example), and backup first! An even more dangerous +option is 'force_addr=<IOPORT>'. This will not only enable the PIIX4 like +'force' foes, but it will also set a new base I/O port address. The SMBus +parts of the PIIX4 needs a range of 8 of these addresses to function +correctly. If these addresses are already reserved by some other device, +you will get into big trouble! DON'T USE THIS IF YOU ARE NOT VERY SURE +ABOUT WHAT YOU ARE DOING! + +The PIIX4E is just an new version of the PIIX4; it is supported as well. +The PIIX/PIIX3 does not implement an SMBus or I2C bus, so you can't use +this driver on those mainboards. + +The ServerWorks Southbridges, the Intel 440MX, and the Victory766 are +identical to the PIIX4 in I2C/SMBus support. + +A few OSB4 southbridges are known to be misconfigured by the BIOS. In this +case, you have you use the fix_hstcfg module parameter. Do not use it +unless you know you have to, because in some cases it also breaks +configuration on southbridges that don't need it. diff --git a/Documentation/i2c/busses/i2c-prosavage b/Documentation/i2c/busses/i2c-prosavage new file mode 100644 index 000000000000..703687902511 --- /dev/null +++ b/Documentation/i2c/busses/i2c-prosavage @@ -0,0 +1,23 @@ +Kernel driver i2c-prosavage + +Supported adapters: + + S3/VIA KM266/VT8375 aka ProSavage8 + S3/VIA KM133/VT8365 aka Savage4 + +Author: Henk Vergonet <henk@god.dyndns.org> + +Description +----------- + +The Savage4 chips contain two I2C interfaces (aka a I2C 'master' or +'host'). + +The first interface is used for DDC (Data Display Channel) which is a +serial channel through the VGA monitor connector to a DDC-compliant +monitor. This interface is defined by the Video Electronics Standards +Association (VESA). The standards are available for purchase at +http://www.vesa.org . The second interface is a general-purpose I2C bus. + +Usefull for gaining access to the TV Encoder chips. + diff --git a/Documentation/i2c/busses/i2c-savage4 b/Documentation/i2c/busses/i2c-savage4 new file mode 100644 index 000000000000..6ecceab618d3 --- /dev/null +++ b/Documentation/i2c/busses/i2c-savage4 @@ -0,0 +1,26 @@ +Kernel driver i2c-savage4 + +Supported adapters: + * Savage4 + * Savage2000 + +Authors: + Alexander Wold <awold@bigfoot.com>, + Mark D. Studebaker <mdsxyz123@yahoo.com> + +Description +----------- + +The Savage4 chips contain two I2C interfaces (aka a I2C 'master' +or 'host'). + +The first interface is used for DDC (Data Display Channel) which is a +serial channel through the VGA monitor connector to a DDC-compliant +monitor. This interface is defined by the Video Electronics Standards +Association (VESA). The standards are available for purchase at +http://www.vesa.org . The DDC bus is not yet supported because its register +is not directly memory-mapped. + +The second interface is a general-purpose I2C bus. This is the only +interface supported by the driver at the moment. + diff --git a/Documentation/i2c/busses/i2c-sis5595 b/Documentation/i2c/busses/i2c-sis5595 new file mode 100644 index 000000000000..cc47db7d00a9 --- /dev/null +++ b/Documentation/i2c/busses/i2c-sis5595 @@ -0,0 +1,59 @@ +Kernel driver i2c-sis5595 + +Authors: + Frodo Looijaard <frodol@dds.nl>, + Mark D. Studebaker <mdsxyz123@yahoo.com>, + Philip Edelbrock <phil@netroedge.com> + +Supported adapters: + * Silicon Integrated Systems Corp. SiS5595 Southbridge + Datasheet: Publicly available at the Silicon Integrated Systems Corp. site. + +Note: all have mfr. ID 0x1039. + + SUPPORTED PCI ID + 5595 0008 + + Note: these chips contain a 0008 device which is incompatible with the + 5595. We recognize these by the presence of the listed + "blacklist" PCI ID and refuse to load. + + NOT SUPPORTED PCI ID BLACKLIST PCI ID + 540 0008 0540 + 550 0008 0550 + 5513 0008 5511 + 5581 0008 5597 + 5582 0008 5597 + 5597 0008 5597 + 5598 0008 5597/5598 + 630 0008 0630 + 645 0008 0645 + 646 0008 0646 + 648 0008 0648 + 650 0008 0650 + 651 0008 0651 + 730 0008 0730 + 735 0008 0735 + 745 0008 0745 + 746 0008 0746 + +Module Parameters +----------------- + +* force_addr=0xaddr Set the I/O base address. Useful for boards + that don't set the address in the BIOS. Does not do a + PCI force; the device must still be present in lspci. + Don't use this unless the driver complains that the + base address is not set. + +Description +----------- + +i2c-sis5595 is a true SMBus host driver for motherboards with the SiS5595 +southbridges. + +WARNING: If you are trying to access the integrated sensors on the SiS5595 +chip, you want the sis5595 driver for those, not this driver. This driver +is a BUS driver, not a CHIP driver. A BUS driver is used by other CHIP +drivers to access chips on the bus. + diff --git a/Documentation/i2c/busses/i2c-sis630 b/Documentation/i2c/busses/i2c-sis630 new file mode 100644 index 000000000000..9aca6889f748 --- /dev/null +++ b/Documentation/i2c/busses/i2c-sis630 @@ -0,0 +1,49 @@ +Kernel driver i2c-sis630 + +Supported adapters: + * Silicon Integrated Systems Corp (SiS) + 630 chipset (Datasheet: available at http://amalysh.bei.t-online.de/docs/SIS/) + 730 chipset + * Possible other SiS chipsets ? + +Author: Alexander Malysh <amalysh@web.de> + +Module Parameters +----------------- + +* force = [1|0] Forcibly enable the SIS630. DANGEROUS! + This can be interesting for chipsets not named + above to check if it works for you chipset, but DANGEROUS! + +* high_clock = [1|0] Forcibly set Host Master Clock to 56KHz (default, + what your BIOS use). DANGEROUS! This should be a bit + faster, but freeze some systems (i.e. my Laptop). + + +Description +----------- + +This SMBus only driver is known to work on motherboards with the above +named chipsets. + +If you see something like this: + +00:00.0 Host bridge: Silicon Integrated Systems [SiS] 630 Host (rev 31) +00:01.0 ISA bridge: Silicon Integrated Systems [SiS] 85C503/5513 + +or like this: + +00:00.0 Host bridge: Silicon Integrated Systems [SiS] 730 Host (rev 02) +00:01.0 ISA bridge: Silicon Integrated Systems [SiS] 85C503/5513 + +in your 'lspci' output , then this driver is for your chipset. + +Thank You +--------- +Philip Edelbrock <phil@netroedge.com> +- testing SiS730 support +Mark M. Hoffman <mhoffman@lightlink.com> +- bug fixes + +To anyone else which I forgot here ;), thanks! + diff --git a/Documentation/i2c/busses/i2c-sis69x b/Documentation/i2c/busses/i2c-sis69x new file mode 100644 index 000000000000..5be48769f65b --- /dev/null +++ b/Documentation/i2c/busses/i2c-sis69x @@ -0,0 +1,73 @@ +Kernel driver i2c-sis96x + +Replaces 2.4.x i2c-sis645 + +Supported adapters: + * Silicon Integrated Systems Corp (SiS) + Any combination of these host bridges: + 645, 645DX (aka 646), 648, 650, 651, 655, 735, 745, 746 + and these south bridges: + 961, 962, 963(L) + +Author: Mark M. Hoffman <mhoffman@lightlink.com> + +Description +----------- + +This SMBus only driver is known to work on motherboards with the above +named chipset combinations. The driver was developed without benefit of a +proper datasheet from SiS. The SMBus registers are assumed compatible with +those of the SiS630, although they are located in a completely different +place. Thanks to Alexander Malysh <amalysh@web.de> for providing the +SiS630 datasheet (and driver). + +The command "lspci" as root should produce something like these lines: + +00:00.0 Host bridge: Silicon Integrated Systems [SiS]: Unknown device 0645 +00:02.0 ISA bridge: Silicon Integrated Systems [SiS] 85C503/5513 +00:02.1 SMBus: Silicon Integrated Systems [SiS]: Unknown device 0016 + +or perhaps this... + +00:00.0 Host bridge: Silicon Integrated Systems [SiS]: Unknown device 0645 +00:02.0 ISA bridge: Silicon Integrated Systems [SiS]: Unknown device 0961 +00:02.1 SMBus: Silicon Integrated Systems [SiS]: Unknown device 0016 + +(kernel versions later than 2.4.18 may fill in the "Unknown"s) + +If you cant see it please look on quirk_sis_96x_smbus +(drivers/pci/quirks.c) (also if southbridge detection fails) + +I suspect that this driver could be made to work for the following SiS +chipsets as well: 635, and 635T. If anyone owns a board with those chips +AND is willing to risk crashing & burning an otherwise well-behaved kernel +in the name of progress... please contact me at <mhoffman@lightlink.com> or +via the project's mailing list: <sensors@stimpy.netroedge.com>. Please +send bug reports and/or success stories as well. + + +TO DOs +------ + +* The driver does not support SMBus block reads/writes; I may add them if a +scenario is found where they're needed. + + +Thank You +--------- + +Mark D. Studebaker <mdsxyz123@yahoo.com> + - design hints and bug fixes +Alexander Maylsh <amalysh@web.de> + - ditto, plus an important datasheet... almost the one I really wanted +Hans-Günter Lütke Uphues <hg_lu@t-online.de> + - patch for SiS735 +Robert Zwerus <arzie@dds.nl> + - testing for SiS645DX +Kianusch Sayah Karadji <kianusch@sk-tech.net> + - patch for SiS645DX/962 +Ken Healy + - patch for SiS655 + +To anyone else who has written w/ feedback, thanks! + diff --git a/Documentation/i2c/busses/i2c-via b/Documentation/i2c/busses/i2c-via new file mode 100644 index 000000000000..55edfe1a640b --- /dev/null +++ b/Documentation/i2c/busses/i2c-via @@ -0,0 +1,34 @@ +Kernel driver i2c-via + +Supported adapters: + * VIA Technologies, InC. VT82C586B + Datasheet: Publicly available at the VIA website + +Author: Kyösti Mälkki <kmalkki@cc.hut.fi> + +Description +----------- + +i2c-via is an i2c bus driver for motherboards with VIA chipset. + +The following VIA pci chipsets are supported: + - MVP3, VP3, VP2/97, VPX/97 + - others with South bridge VT82C586B + +Your lspci listing must show this : + + Bridge: VIA Technologies, Inc. VT82C586B ACPI (rev 10) + + Problems? + + Q: You have VT82C586B on the motherboard, but not in the listing. + + A: Go to your BIOS setup, section PCI devices or similar. + Turn USB support on, and try again. + + Q: No error messages, but still i2c doesn't seem to work. + + A: This can happen. This driver uses the pins VIA recommends in their + datasheets, but there are several ways the motherboard manufacturer + can actually wire the lines. + diff --git a/Documentation/i2c/busses/i2c-viapro b/Documentation/i2c/busses/i2c-viapro new file mode 100644 index 000000000000..702f5ac68c09 --- /dev/null +++ b/Documentation/i2c/busses/i2c-viapro @@ -0,0 +1,47 @@ +Kernel driver i2c-viapro + +Supported adapters: + * VIA Technologies, Inc. VT82C596A/B + Datasheet: Sometimes available at the VIA website + + * VIA Technologies, Inc. VT82C686A/B + Datasheet: Sometimes available at the VIA website + + * VIA Technologies, Inc. VT8231, VT8233, VT8233A, VT8235, VT8237 + Datasheet: available on request from Via + +Authors: + Frodo Looijaard <frodol@dds.nl>, + Philip Edelbrock <phil@netroedge.com>, + Kyösti Mälkki <kmalkki@cc.hut.fi>, + Mark D. Studebaker <mdsxyz123@yahoo.com> + +Module Parameters +----------------- + +* force: int + Forcibly enable the SMBus controller. DANGEROUS! +* force_addr: int + Forcibly enable the SMBus at the given address. EXTREMELY DANGEROUS! + +Description +----------- + +i2c-viapro is a true SMBus host driver for motherboards with one of the +supported VIA southbridges. + +Your lspci -n listing must show one of these : + + device 1106:3050 (VT82C596 function 3) + device 1106:3051 (VT82C596 function 3) + device 1106:3057 (VT82C686 function 4) + device 1106:3074 (VT8233) + device 1106:3147 (VT8233A) + device 1106:8235 (VT8231) + devide 1106:3177 (VT8235) + devide 1106:3227 (VT8237) + +If none of these show up, you should look in the BIOS for settings like +enable ACPI / SMBus or even USB. + + diff --git a/Documentation/i2c/busses/i2c-voodoo3 b/Documentation/i2c/busses/i2c-voodoo3 new file mode 100644 index 000000000000..62d90a454d39 --- /dev/null +++ b/Documentation/i2c/busses/i2c-voodoo3 @@ -0,0 +1,62 @@ +Kernel driver i2c-voodoo3 + +Supported adapters: + * 3dfx Voodoo3 based cards + * Voodoo Banshee based cards + +Authors: + Frodo Looijaard <frodol@dds.nl>, + Philip Edelbrock <phil@netroedge.com>, + Ralph Metzler <rjkm@thp.uni-koeln.de>, + Mark D. Studebaker <mdsxyz123@yahoo.com> + +Main contact: Philip Edelbrock <phil@netroedge.com> + +The code is based upon Ralph's test code (he did the hard stuff ;') + +Description +----------- + +The 3dfx Voodoo3 chip contains two I2C interfaces (aka a I2C 'master' or +'host'). + +The first interface is used for DDC (Data Display Channel) which is a +serial channel through the VGA monitor connector to a DDC-compliant +monitor. This interface is defined by the Video Electronics Standards +Association (VESA). The standards are available for purchase at +http://www.vesa.org . + +The second interface is a general-purpose I2C bus. The intent by 3dfx was +to allow manufacturers to add extra chips to the video card such as a +TV-out chip such as the BT869 or possibly even I2C based temperature +sensors like the ADM1021 or LM75. + +Stability +--------- + +Seems to be stable on the test machine, but needs more testing on other +machines. Simultaneous accesses of the DDC and I2C busses may cause errors. + +Supported Devices +----------------- + +Specifically, this driver was written and tested on the '3dfx Voodoo3 AGP +3000' which has a tv-out feature (s-video or composite). According to the +docs and discussions, this code should work for any Voodoo3 based cards as +well as Voodoo Banshee based cards. The DDC interface has been tested on a +Voodoo Banshee card. + +Issues +------ + +Probably many, but it seems to work OK on my system. :') + + +External Device Connection +-------------------------- + +The digital video input jumpers give availability to the I2C bus. +Specifically, pins 13 and 25 (bottom row middle, and bottom right-end) are +the I2C clock and I2C data lines, respectively. +5V and GND are probably +also easily available making the addition of extra I2C/SMBus devices easy +to implement. diff --git a/Documentation/i2c/busses/scx200_acb b/Documentation/i2c/busses/scx200_acb new file mode 100644 index 000000000000..08c8cd1df60c --- /dev/null +++ b/Documentation/i2c/busses/scx200_acb @@ -0,0 +1,14 @@ +Kernel driver scx200_acb + +Author: Christer Weinigel <wingel@nano-system.com> + +Module Parameters +----------------- + +* base: int + Base addresses for the ACCESS.bus controllers + +Description +----------- + +Enable the use of the ACCESS.bus controllers of a SCx200 processor. diff --git a/Documentation/i2c/chips/smsc47b397.txt b/Documentation/i2c/chips/smsc47b397.txt new file mode 100644 index 000000000000..389edae7f8df --- /dev/null +++ b/Documentation/i2c/chips/smsc47b397.txt @@ -0,0 +1,146 @@ +November 23, 2004 + +The following specification describes the SMSC LPC47B397-NC sensor chip +(for which there is no public datasheet available). This document was +provided by Craig Kelly (In-Store Broadcast Network) and edited/corrected +by Mark M. Hoffman <mhoffman@lightlink.com>. + +* * * * * + +Methods for detecting the HP SIO and reading the thermal data on a dc7100. + +The thermal information on the dc7100 is contained in the SIO Hardware Monitor +(HWM). The information is accessed through an index/data pair. The index/data +pair is located at the HWM Base Address + 0 and the HWM Base Address + 1. The +HWM Base address can be obtained from Logical Device 8, registers 0x60 (MSB) +and 0x61 (LSB). Currently we are using 0x480 for the HWM Base Address and +0x480 and 0x481 for the index/data pair. + +Reading temperature information. +The temperature information is located in the following registers: +Temp1 0x25 (Currently, this reflects the CPU temp on all systems). +Temp2 0x26 +Temp3 0x27 +Temp4 0x80 + +Programming Example +The following is an example of how to read the HWM temperature registers: +MOV DX,480H +MOV AX,25H +OUT DX,AL +MOV DX,481H +IN AL,DX + +AL contains the data in hex, the temperature in Celsius is the decimal +equivalent. + +Ex: If AL contains 0x2A, the temperature is 42 degrees C. + +Reading tach information. +The fan speed information is located in the following registers: + LSB MSB +Tach1 0x28 0x29 (Currently, this reflects the CPU + fan speed on all systems). +Tach2 0x2A 0x2B +Tach3 0x2C 0x2D +Tach4 0x2E 0x2F + +Important!!! +Reading the tach LSB locks the tach MSB. +The LSB Must be read first. + +How to convert the tach reading to RPM. +The tach reading (TCount) is given by: (Tach MSB * 256) + (Tach LSB) +The SIO counts the number of 90kHz (11.111us) pulses per revolution. +RPM = 60/(TCount * 11.111us) + +Example: +Reg 0x28 = 0x9B +Reg 0x29 = 0x08 + +TCount = 0x89B = 2203 + +RPM = 60 / (2203 * 11.11111 E-6) = 2451 RPM + +Obtaining the SIO version. + +CONFIGURATION SEQUENCE +To program the configuration registers, the following sequence must be followed: +1. Enter Configuration Mode +2. Configure the Configuration Registers +3. Exit Configuration Mode. + +Enter Configuration Mode +To place the chip into the Configuration State The config key (0x55) is written +to the CONFIG PORT (0x2E). + +Configuration Mode +In configuration mode, the INDEX PORT is located at the CONFIG PORT address and +the DATA PORT is at INDEX PORT address + 1. + +The desired configuration registers are accessed in two steps: +a. Write the index of the Logical Device Number Configuration Register + (i.e., 0x07) to the INDEX PORT and then write the number of the + desired logical device to the DATA PORT. + +b. Write the address of the desired configuration register within the + logical device to the INDEX PORT and then write or read the config- + uration register through the DATA PORT. + +Note: If accessing the Global Configuration Registers, step (a) is not required. + +Exit Configuration Mode +To exit the Configuration State the write 0xAA to the CONFIG PORT (0x2E). +The chip returns to the RUN State. (This is important). + +Programming Example +The following is an example of how to read the SIO Device ID located at 0x20 + +; ENTER CONFIGURATION MODE +MOV DX,02EH +MOV AX,055H +OUT DX,AL +; GLOBAL CONFIGURATION REGISTER +MOV DX,02EH +MOV AL,20H +OUT DX,AL +; READ THE DATA +MOV DX,02FH +IN AL,DX +; EXIT CONFIGURATION MODE +MOV DX,02EH +MOV AX,0AAH +OUT DX,AL + +The registers of interest for identifying the SIO on the dc7100 are Device ID +(0x20) and Device Rev (0x21). + +The Device ID will read 0X6F +The Device Rev currently reads 0x01 + +Obtaining the HWM Base Address. +The following is an example of how to read the HWM Base Address located in +Logical Device 8. + +; ENTER CONFIGURATION MODE +MOV DX,02EH +MOV AX,055H +OUT DX,AL +; CONFIGURE REGISTER CRE0, +; LOGICAL DEVICE 8 +MOV DX,02EH +MOV AL,07H +OUT DX,AL ;Point to LD# Config Reg +MOV DX,02FH +MOV AL, 08H +OUT DX,AL;Point to Logical Device 8 +; +MOV DX,02EH +MOV AL,60H +OUT DX,AL ; Point to HWM Base Addr MSB +MOV DX,02FH +IN AL,DX ; Get MSB of HWM Base Addr +; EXIT CONFIGURATION MODE +MOV DX,02EH +MOV AX,0AAH +OUT DX,AL diff --git a/Documentation/i2c/dev-interface b/Documentation/i2c/dev-interface new file mode 100644 index 000000000000..09d6cda2a1fb --- /dev/null +++ b/Documentation/i2c/dev-interface @@ -0,0 +1,146 @@ +Usually, i2c devices are controlled by a kernel driver. But it is also +possible to access all devices on an adapter from userspace, through +the /dev interface. You need to load module i2c-dev for this. + +Each registered i2c adapter gets a number, counting from 0. You can +examine /sys/class/i2c-dev/ to see what number corresponds to which adapter. +I2C device files are character device files with major device number 89 +and a minor device number corresponding to the number assigned as +explained above. They should be called "i2c-%d" (i2c-0, i2c-1, ..., +i2c-10, ...). All 256 minor device numbers are reserved for i2c. + + +C example +========= + +So let's say you want to access an i2c adapter from a C program. The +first thing to do is `#include <linux/i2c.h>" and "#include <linux/i2c-dev.h>. +Yes, I know, you should never include kernel header files, but until glibc +knows about i2c, there is not much choice. + +Now, you have to decide which adapter you want to access. You should +inspect /sys/class/i2c-dev/ to decide this. Adapter numbers are assigned +somewhat dynamically, so you can not even assume /dev/i2c-0 is the +first adapter. + +Next thing, open the device file, as follows: + int file; + int adapter_nr = 2; /* probably dynamically determined */ + char filename[20]; + + sprintf(filename,"/dev/i2c-%d",adapter_nr); + if ((file = open(filename,O_RDWR)) < 0) { + /* ERROR HANDLING; you can check errno to see what went wrong */ + exit(1); + } + +When you have opened the device, you must specify with what device +address you want to communicate: + int addr = 0x40; /* The I2C address */ + if (ioctl(file,I2C_SLAVE,addr) < 0) { + /* ERROR HANDLING; you can check errno to see what went wrong */ + exit(1); + } + +Well, you are all set up now. You can now use SMBus commands or plain +I2C to communicate with your device. SMBus commands are preferred if +the device supports them. Both are illustrated below. + __u8 register = 0x10; /* Device register to access */ + __s32 res; + char buf[10]; + /* Using SMBus commands */ + res = i2c_smbus_read_word_data(file,register); + if (res < 0) { + /* ERROR HANDLING: i2c transaction failed */ + } else { + /* res contains the read word */ + } + /* Using I2C Write, equivalent of + i2c_smbus_write_word_data(file,register,0x6543) */ + buf[0] = register; + buf[1] = 0x43; + buf[2] = 0x65; + if ( write(file,buf,3) != 3) { + /* ERROR HANDLING: i2c transaction failed */ + } + /* Using I2C Read, equivalent of i2c_smbus_read_byte(file) */ + if (read(file,buf,1) != 1) { + /* ERROR HANDLING: i2c transaction failed */ + } else { + /* buf[0] contains the read byte */ + } + +IMPORTANT: because of the use of inline functions, you *have* to use +'-O' or some variation when you compile your program! + + +Full interface description +========================== + +The following IOCTLs are defined and fully supported +(see also i2c-dev.h and i2c.h): + +ioctl(file,I2C_SLAVE,long addr) + Change slave address. The address is passed in the 7 lower bits of the + argument (except for 10 bit addresses, passed in the 10 lower bits in this + case). + +ioctl(file,I2C_TENBIT,long select) + Selects ten bit addresses if select not equals 0, selects normal 7 bit + addresses if select equals 0. Default 0. + +ioctl(file,I2C_PEC,long select) + Selects SMBus PEC (packet error checking) generation and verification + if select not equals 0, disables if select equals 0. Default 0. + Used only for SMBus transactions. + +ioctl(file,I2C_FUNCS,unsigned long *funcs) + Gets the adapter functionality and puts it in *funcs. + +ioctl(file,I2C_RDWR,struct i2c_ioctl_rdwr_data *msgset) + + Do combined read/write transaction without stop in between. + The argument is a pointer to a struct i2c_ioctl_rdwr_data { + + struct i2c_msg *msgs; /* ptr to array of simple messages */ + int nmsgs; /* number of messages to exchange */ + } + + The msgs[] themselves contain further pointers into data buffers. + The function will write or read data to or from that buffers depending + on whether the I2C_M_RD flag is set in a particular message or not. + The slave address and whether to use ten bit address mode has to be + set in each message, overriding the values set with the above ioctl's. + + +Other values are NOT supported at this moment, except for I2C_SMBUS, +which you should never directly call; instead, use the access functions +below. + +You can do plain i2c transactions by using read(2) and write(2) calls. +You do not need to pass the address byte; instead, set it through +ioctl I2C_SLAVE before you try to access the device. + +You can do SMBus level transactions (see documentation file smbus-protocol +for details) through the following functions: + __s32 i2c_smbus_write_quick(int file, __u8 value); + __s32 i2c_smbus_read_byte(int file); + __s32 i2c_smbus_write_byte(int file, __u8 value); + __s32 i2c_smbus_read_byte_data(int file, __u8 command); + __s32 i2c_smbus_write_byte_data(int file, __u8 command, __u8 value); + __s32 i2c_smbus_read_word_data(int file, __u8 command); + __s32 i2c_smbus_write_word_data(int file, __u8 command, __u16 value); + __s32 i2c_smbus_process_call(int file, __u8 command, __u16 value); + __s32 i2c_smbus_read_block_data(int file, __u8 command, __u8 *values); + __s32 i2c_smbus_write_block_data(int file, __u8 command, __u8 length, + __u8 *values); +All these transactions return -1 on failure; you can read errno to see +what happened. The 'write' transactions return 0 on success; the +'read' transactions return the read value, except for read_block, which +returns the number of values read. The block buffers need not be longer +than 32 bytes. + +The above functions are all macros, that resolve to calls to the +i2c_smbus_access function, that on its turn calls a specific ioctl +with the data in a specific format. Read the source code if you +want to know what happens behind the screens. diff --git a/Documentation/i2c/functionality b/Documentation/i2c/functionality new file mode 100644 index 000000000000..8a78a95ae04e --- /dev/null +++ b/Documentation/i2c/functionality @@ -0,0 +1,135 @@ +INTRODUCTION +------------ + +Because not every I2C or SMBus adapter implements everything in the +I2C specifications, a client can not trust that everything it needs +is implemented when it is given the option to attach to an adapter: +the client needs some way to check whether an adapter has the needed +functionality. + + +FUNCTIONALITY CONSTANTS +----------------------- + +For the most up-to-date list of functionality constants, please check +<linux/i2c.h>! + + I2C_FUNC_I2C Plain i2c-level commands (Pure SMBus + adapters typically can not do these) + I2C_FUNC_10BIT_ADDR Handles the 10-bit address extensions + I2C_FUNC_PROTOCOL_MANGLING Knows about the I2C_M_REV_DIR_ADDR, + I2C_M_REV_DIR_ADDR and I2C_M_REV_DIR_NOSTART + flags (which modify the i2c protocol!) + I2C_FUNC_SMBUS_QUICK Handles the SMBus write_quick command + I2C_FUNC_SMBUS_READ_BYTE Handles the SMBus read_byte command + I2C_FUNC_SMBUS_WRITE_BYTE Handles the SMBus write_byte command + I2C_FUNC_SMBUS_READ_BYTE_DATA Handles the SMBus read_byte_data command + I2C_FUNC_SMBUS_WRITE_BYTE_DATA Handles the SMBus write_byte_data command + I2C_FUNC_SMBUS_READ_WORD_DATA Handles the SMBus read_word_data command + I2C_FUNC_SMBUS_WRITE_WORD_DATA Handles the SMBus write_byte_data command + I2C_FUNC_SMBUS_PROC_CALL Handles the SMBus process_call command + I2C_FUNC_SMBUS_READ_BLOCK_DATA Handles the SMBus read_block_data command + I2C_FUNC_SMBUS_WRITE_BLOCK_DATA Handles the SMBus write_block_data command + I2C_FUNC_SMBUS_READ_I2C_BLOCK Handles the SMBus read_i2c_block_data command + I2C_FUNC_SMBUS_WRITE_I2C_BLOCK Handles the SMBus write_i2c_block_data command + +A few combinations of the above flags are also defined for your convenience: + + I2C_FUNC_SMBUS_BYTE Handles the SMBus read_byte + and write_byte commands + I2C_FUNC_SMBUS_BYTE_DATA Handles the SMBus read_byte_data + and write_byte_data commands + I2C_FUNC_SMBUS_WORD_DATA Handles the SMBus read_word_data + and write_word_data commands + I2C_FUNC_SMBUS_BLOCK_DATA Handles the SMBus read_block_data + and write_block_data commands + I2C_FUNC_SMBUS_I2C_BLOCK Handles the SMBus read_i2c_block_data + and write_i2c_block_data commands + I2C_FUNC_SMBUS_EMUL Handles all SMBus commands than can be + emulated by a real I2C adapter (using + the transparent emulation layer) + + +ALGORITHM/ADAPTER IMPLEMENTATION +-------------------------------- + +When you write a new algorithm driver, you will have to implement a +function callback `functionality', that gets an i2c_adapter structure +pointer as its only parameter: + + struct i2c_algorithm { + /* Many other things of course; check <linux/i2c.h>! */ + u32 (*functionality) (struct i2c_adapter *); + } + +A typically implementation is given below, from i2c-algo-bit.c: + + static u32 bit_func(struct i2c_adapter *adap) + { + return I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR | + I2C_FUNC_PROTOCOL_MANGLING; + } + + + +CLIENT CHECKING +--------------- + +Before a client tries to attach to an adapter, or even do tests to check +whether one of the devices it supports is present on an adapter, it should +check whether the needed functionality is present. There are two functions +defined which should be used instead of calling the functionality hook +in the algorithm structure directly: + + /* Return the functionality mask */ + extern u32 i2c_get_functionality (struct i2c_adapter *adap); + + /* Return 1 if adapter supports everything we need, 0 if not. */ + extern int i2c_check_functionality (struct i2c_adapter *adap, u32 func); + +This is a typical way to use these functions (from the writing-clients +document): + int foo_detect_client(struct i2c_adapter *adapter, int address, + unsigned short flags, int kind) + { + /* Define needed variables */ + + /* As the very first action, we check whether the adapter has the + needed functionality: we need the SMBus read_word_data, + write_word_data and write_byte functions in this example. */ + if (!i2c_check_functionality(adapter,I2C_FUNC_SMBUS_WORD_DATA | + I2C_FUNC_SMBUS_WRITE_BYTE)) + goto ERROR0; + + /* Now we can do the real detection */ + + ERROR0: + /* Return an error */ + } + + + +CHECKING THROUGH /DEV +--------------------- + +If you try to access an adapter from a userspace program, you will have +to use the /dev interface. You will still have to check whether the +functionality you need is supported, of course. This is done using +the I2C_FUNCS ioctl. An example, adapted from the lm_sensors i2c_detect +program, is below: + + int file; + if (file = open("/dev/i2c-0",O_RDWR) < 0) { + /* Some kind of error handling */ + exit(1); + } + if (ioctl(file,I2C_FUNCS,&funcs) < 0) { + /* Some kind of error handling */ + exit(1); + } + if (! (funcs & I2C_FUNC_SMBUS_QUICK)) { + /* Oops, the needed functionality (SMBus write_quick function) is + not available! */ + exit(1); + } + /* Now it is safe to use the SMBus write_quick command */ diff --git a/Documentation/i2c/i2c-protocol b/Documentation/i2c/i2c-protocol new file mode 100644 index 000000000000..b4022c914210 --- /dev/null +++ b/Documentation/i2c/i2c-protocol @@ -0,0 +1,76 @@ +This document describes the i2c protocol. Or will, when it is finished :-) + +Key to symbols +============== + +S (1 bit) : Start bit +P (1 bit) : Stop bit +Rd/Wr (1 bit) : Read/Write bit. Rd equals 1, Wr equals 0. +A, NA (1 bit) : Accept and reverse accept bit. +Addr (7 bits): I2C 7 bit address. Note that this can be expanded as usual to + get a 10 bit I2C address. +Comm (8 bits): Command byte, a data byte which often selects a register on + the device. +Data (8 bits): A plain data byte. Sometimes, I write DataLow, DataHigh + for 16 bit data. +Count (8 bits): A data byte containing the length of a block operation. + +[..]: Data sent by I2C device, as opposed to data sent by the host adapter. + + +Simple send transaction +====================== + +This corresponds to i2c_master_send. + + S Addr Wr [A] Data [A] Data [A] ... [A] Data [A] P + + +Simple receive transaction +=========================== + +This corresponds to i2c_master_recv + + S Addr Rd [A] [Data] A [Data] A ... A [Data] NA P + + +Combined transactions +==================== + +This corresponds to i2c_transfer + +They are just like the above transactions, but instead of a stop bit P +a start bit S is sent and the transaction continues. An example of +a byte read, followed by a byte write: + + S Addr Rd [A] [Data] NA S Addr Wr [A] Data [A] P + + +Modified transactions +===================== + +We have found some I2C devices that needs the following modifications: + + Flag I2C_M_NOSTART: + In a combined transaction, no 'S Addr Wr/Rd [A]' is generated at some + point. For example, setting I2C_M_NOSTART on the second partial message + generates something like: + S Addr Rd [A] [Data] NA Data [A] P + If you set the I2C_M_NOSTART variable for the first partial message, + we do not generate Addr, but we do generate the startbit S. This will + probably confuse all other clients on your bus, so don't try this. + + Flags I2C_M_REV_DIR_ADDR + This toggles the Rd/Wr flag. That is, if you want to do a write, but + need to emit an Rd instead of a Wr, or vice versa, you set this + flag. For example: + S Addr Rd [A] Data [A] Data [A] ... [A] Data [A] P + + Flags I2C_M_IGNORE_NAK + Normally message is interrupted immediately if there is [NA] from the + client. Setting this flag treats any [NA] as [A], and all of + message is sent. + These messages may still fail to SCL lo->hi timeout. + + Flags I2C_M_NO_RD_ACK + In a read message, master A/NA bit is skipped. diff --git a/Documentation/i2c/i2c-stub b/Documentation/i2c/i2c-stub new file mode 100644 index 000000000000..d6dcb138abf5 --- /dev/null +++ b/Documentation/i2c/i2c-stub @@ -0,0 +1,38 @@ +MODULE: i2c-stub + +DESCRIPTION: + +This module is a very simple fake I2C/SMBus driver. It implements four +types of SMBus commands: write quick, (r/w) byte, (r/w) byte data, and +(r/w) word data. + +No hardware is needed nor associated with this module. It will accept write +quick commands to all addresses; it will respond to the other commands (also +to all addresses) by reading from or writing to an array in memory. It will +also spam the kernel logs for every command it handles. + +A pointer register with auto-increment is implemented for all byte +operations. This allows for continuous byte reads like those supported by +EEPROMs, among others. + +The typical use-case is like this: + 1. load this module + 2. use i2cset (from lm_sensors project) to pre-load some data + 3. load the target sensors chip driver module + 4. observe its behavior in the kernel log + +CAVEATS: + +There are independent arrays for byte/data and word/data commands. Depending +on if/how a target driver mixes them, you'll need to be careful. + +If your target driver polls some byte or word waiting for it to change, the +stub could lock it up. Use i2cset to unlock it. + +If the hardware for your driver has banked registers (e.g. Winbond sensors +chips) this module will not work well - although it could be extended to +support that pretty easily. + +If you spam it hard enough, printk can be lossy. This module really wants +something like relayfs. + diff --git a/Documentation/i2c/porting-clients b/Documentation/i2c/porting-clients new file mode 100644 index 000000000000..56404918eabc --- /dev/null +++ b/Documentation/i2c/porting-clients @@ -0,0 +1,133 @@ +Revision 4, 2004-03-30 +Jean Delvare <khali@linux-fr.org> +Greg KH <greg@kroah.com> + +This is a guide on how to convert I2C chip drivers from Linux 2.4 to +Linux 2.6. I have been using existing drivers (lm75, lm78) as examples. +Then I converted a driver myself (lm83) and updated this document. + +There are two sets of points below. The first set concerns technical +changes. The second set concerns coding policy. Both are mandatory. + +Although reading this guide will help you porting drivers, I suggest +you keep an eye on an already ported driver while porting your own +driver. This will help you a lot understanding what this guide +exactly means. Choose the chip driver that is the more similar to +yours for best results. + +Technical changes: + +* [Includes] Get rid of "version.h". Replace <linux/i2c-proc.h> with + <linux/i2c-sensor.h>. Includes typically look like that: + #include <linux/module.h> + #include <linux/init.h> + #include <linux/slab.h> + #include <linux/i2c.h> + #include <linux/i2c-sensor.h> + #include <linux/i2c-vid.h> /* if you need VRM support */ + #include <asm/io.h> /* if you have I/O operations */ + Please respect this inclusion order. Some extra headers may be + required for a given driver (e.g. "lm75.h"). + +* [Addresses] SENSORS_I2C_END becomes I2C_CLIENT_END, SENSORS_ISA_END + becomes I2C_CLIENT_ISA_END. + +* [Client data] Get rid of sysctl_id. Try using standard names for + register values (for example, temp_os becomes temp_max). You're + still relatively free here, but you *have* to follow the standard + names for sysfs files (see the Sysctl section below). + +* [Function prototypes] The detect functions loses its flags + parameter. Sysctl (e.g. lm75_temp) and miscellaneous functions + are off the list of prototypes. This usually leaves five + prototypes: + static int lm75_attach_adapter(struct i2c_adapter *adapter); + static int lm75_detect(struct i2c_adapter *adapter, int address, + int kind); + static void lm75_init_client(struct i2c_client *client); + static int lm75_detach_client(struct i2c_client *client); + static void lm75_update_client(struct i2c_client *client); + +* [Sysctl] All sysctl stuff is of course gone (defines, ctl_table + and functions). Instead, you have to define show and set functions for + each sysfs file. Only define set for writable values. Take a look at an + existing 2.6 driver for details (lm78 for example). Don't forget + to define the attributes for each file (this is that step that + links callback functions). Use the file names specified in + Documentation/i2c/sysfs-interface for the individual files. Also + convert the units these files read and write to the specified ones. + If you need to add a new type of file, please discuss it on the + sensors mailing list <sensors@stimpy.netroedge.com> by providing a + patch to the Documentation/i2c/sysfs-interface file. + +* [Attach] For I2C drivers, the attach function should make sure + that the adapter's class has I2C_CLASS_HWMON, using the + following construct: + if (!(adapter->class & I2C_CLASS_HWMON)) + return 0; + ISA-only drivers of course don't need this. + +* [Detect] As mentioned earlier, the flags parameter is gone. + The type_name and client_name strings are replaced by a single + name string, which will be filled with a lowercase, short string + (typically the driver name, e.g. "lm75"). + In i2c-only drivers, drop the i2c_is_isa_adapter check, it's + useless. + The errorN labels are reduced to the number needed. If that number + is 2 (i2c-only drivers), it is advised that the labels are named + exit and exit_free. For i2c+isa drivers, labels should be named + ERROR0, ERROR1 and ERROR2. Don't forget to properly set err before + jumping to error labels. By the way, labels should be left-aligned. + Use memset to fill the client and data area with 0x00. + Use i2c_set_clientdata to set the client data (as opposed to + a direct access to client->data). + Use strlcpy instead of strcpy to copy the client name. + Replace the sysctl directory registration by calls to + device_create_file. Move the driver initialization before any + sysfs file creation. + Drop client->id. + +* [Init] Limits must not be set by the driver (can be done later in + user-space). Chip should not be reset default (although a module + parameter may be used to force is), and initialization should be + limited to the strictly necessary steps. + +* [Detach] Get rid of data, remove the call to + i2c_deregister_entry. + +* [Update] Don't access client->data directly, use + i2c_get_clientdata(client) instead. + +* [Interface] Init function should not print anything. Make sure + there is a MODULE_LICENSE() line, at the bottom of the file + (after MODULE_AUTHOR() and MODULE_DESCRIPTION(), in this order). + +Coding policy: + +* [Copyright] Use (C), not (c), for copyright. + +* [Debug/log] Get rid of #ifdef DEBUG/#endif constructs whenever you + can. Calls to printk/pr_debug for debugging purposes are replaced + by calls to dev_dbg. Here is an example on how to call it (taken + from lm75_detect): + dev_dbg(&client->dev, "Starting lm75 update\n"); + Replace other printk calls with the dev_info, dev_err or dev_warn + function, as appropriate. + +* [Constants] Constants defines (registers, conversions, initial + values) should be aligned. This greatly improves readability. + Same goes for variables declarations. Alignments are achieved by the + means of tabs, not spaces. Remember that tabs are set to 8 in the + Linux kernel code. + +* [Structure definition] The name field should be standardized. All + lowercase and as simple as the driver name itself (e.g. "lm75"). + +* [Layout] Avoid extra empty lines between comments and what they + comment. Respect the coding style (see Documentation/CodingStyle), + in particular when it comes to placing curly braces. + +* [Comments] Make sure that no comment refers to a file that isn't + part of the Linux source tree (typically doc/chips/<chip name>), + and that remaining comments still match the code. Merging comment + lines when possible is encouraged. diff --git a/Documentation/i2c/smbus-protocol b/Documentation/i2c/smbus-protocol new file mode 100644 index 000000000000..09f5e5ca4927 --- /dev/null +++ b/Documentation/i2c/smbus-protocol @@ -0,0 +1,216 @@ +SMBus Protocol Summary +====================== +The following is a summary of the SMBus protocol. It applies to +all revisions of the protocol (1.0, 1.1, and 2.0). +Certain protocol features which are not supported by +this package are briefly described at the end of this document. + +Some adapters understand only the SMBus (System Management Bus) protocol, +which is a subset from the I2C protocol. Fortunately, many devices use +only the same subset, which makes it possible to put them on an SMBus. +If you write a driver for some I2C device, please try to use the SMBus +commands if at all possible (if the device uses only that subset of the +I2C protocol). This makes it possible to use the device driver on both +SMBus adapters and I2C adapters (the SMBus command set is automatically +translated to I2C on I2C adapters, but plain I2C commands can not be +handled at all on most pure SMBus adapters). + +Below is a list of SMBus commands. + +Key to symbols +============== + +S (1 bit) : Start bit +P (1 bit) : Stop bit +Rd/Wr (1 bit) : Read/Write bit. Rd equals 1, Wr equals 0. +A, NA (1 bit) : Accept and reverse accept bit. +Addr (7 bits): I2C 7 bit address. Note that this can be expanded as usual to + get a 10 bit I2C address. +Comm (8 bits): Command byte, a data byte which often selects a register on + the device. +Data (8 bits): A plain data byte. Sometimes, I write DataLow, DataHigh + for 16 bit data. +Count (8 bits): A data byte containing the length of a block operation. + +[..]: Data sent by I2C device, as opposed to data sent by the host adapter. + + +SMBus Write Quick +================= + +This sends a single bit to the device, at the place of the Rd/Wr bit. +There is no equivalent Read Quick command. + +A Addr Rd/Wr [A] P + + +SMBus Read Byte +=============== + +This reads a single byte from a device, without specifying a device +register. Some devices are so simple that this interface is enough; for +others, it is a shorthand if you want to read the same register as in +the previous SMBus command. + +S Addr Rd [A] [Data] NA P + + +SMBus Write Byte +================ + +This is the reverse of Read Byte: it sends a single byte to a device. +See Read Byte for more information. + +S Addr Wr [A] Data [A] P + + +SMBus Read Byte Data +==================== + +This reads a single byte from a device, from a designated register. +The register is specified through the Comm byte. + +S Addr Wr [A] Comm [A] S Addr Rd [A] [Data] NA P + + +SMBus Read Word Data +==================== + +This command is very like Read Byte Data; again, data is read from a +device, from a designated register that is specified through the Comm +byte. But this time, the data is a complete word (16 bits). + +S Addr Wr [A] Comm [A] S Addr Rd [A] [DataLow] A [DataHigh] NA P + + +SMBus Write Byte Data +===================== + +This writes a single byte to a device, to a designated register. The +register is specified through the Comm byte. This is the opposite of +the Read Byte Data command. + +S Addr Wr [A] Comm [A] Data [A] P + + +SMBus Write Word Data +===================== + +This is the opposite operation of the Read Word Data command. 16 bits +of data is read from a device, from a designated register that is +specified through the Comm byte. + +S Addr Wr [A] Comm [A] DataLow [A] DataHigh [A] P + + +SMBus Process Call +================== + +This command selects a device register (through the Comm byte), sends +16 bits of data to it, and reads 16 bits of data in return. + +S Addr Wr [A] Comm [A] DataLow [A] DataHigh [A] + S Addr Rd [A] [DataLow] A [DataHigh] NA P + + +SMBus Block Read +================ + +This command reads a block of up to 32 bytes from a device, from a +designated register that is specified through the Comm byte. The amount +of data is specified by the device in the Count byte. + +S Addr Wr [A] Comm [A] + S Addr Rd [A] [Count] A [Data] A [Data] A ... A [Data] NA P + + +SMBus Block Write +================= + +The opposite of the Block Read command, this writes up to 32 bytes to +a device, to a designated register that is specified through the +Comm byte. The amount of data is specified in the Count byte. + +S Addr Wr [A] Comm [A] Count [A] Data [A] Data [A] ... [A] Data [A] P + + +SMBus Block Process Call +======================== + +SMBus Block Process Call was introduced in Revision 2.0 of the specification. + +This command selects a device register (through the Comm byte), sends +1 to 31 bytes of data to it, and reads 1 to 31 bytes of data in return. + +S Addr Wr [A] Comm [A] Count [A] Data [A] ... + S Addr Rd [A] [Count] A [Data] ... A P + + +SMBus Host Notify +================= + +This command is sent from a SMBus device acting as a master to the +SMBus host acting as a slave. +It is the same form as Write Word, with the command code replaced by the +alerting device's address. + +[S] [HostAddr] [Wr] A [DevAddr] A [DataLow] A [DataHigh] A [P] + + +Packet Error Checking (PEC) +=========================== +Packet Error Checking was introduced in Revision 1.1 of the specification. + +PEC adds a CRC-8 error-checking byte to all transfers. + + +Address Resolution Protocol (ARP) +================================= +The Address Resolution Protocol was introduced in Revision 2.0 of +the specification. It is a higher-layer protocol which uses the +messages above. + +ARP adds device enumeration and dynamic address assignment to +the protocol. All ARP communications use slave address 0x61 and +require PEC checksums. + + +I2C Block Transactions +====================== +The following I2C block transactions are supported by the +SMBus layer and are described here for completeness. +I2C block transactions do not limit the number of bytes transferred +but the SMBus layer places a limit of 32 bytes. + + +I2C Block Read +============== + +This command reads a block of bytes from a device, from a +designated register that is specified through the Comm byte. + +S Addr Wr [A] Comm [A] + S Addr Rd [A] [Data] A [Data] A ... A [Data] NA P + + +I2C Block Read (2 Comm bytes) +============================= + +This command reads a block of bytes from a device, from a +designated register that is specified through the two Comm bytes. + +S Addr Wr [A] Comm1 [A] Comm2 [A] + S Addr Rd [A] [Data] A [Data] A ... A [Data] NA P + + +I2C Block Write +=============== + +The opposite of the Block Read command, this writes bytes to +a device, to a designated register that is specified through the +Comm byte. Note that command lengths of 0, 2, or more bytes are +supported as they are indistinguishable from data. + +S Addr Wr [A] Comm [A] Data [A] Data [A] ... [A] Data [A] P + + diff --git a/Documentation/i2c/summary b/Documentation/i2c/summary new file mode 100644 index 000000000000..41dde8776791 --- /dev/null +++ b/Documentation/i2c/summary @@ -0,0 +1,75 @@ +This is an explanation of what i2c is, and what is supported in this package. + +I2C and SMBus +============= + +I2C (pronounce: I squared C) is a protocol developed by Philips. It is a +slow two-wire protocol (10-400 kHz), but it suffices for many types of +devices. + +SMBus (System Management Bus) is a subset of the I2C protocol. Many +modern mainboards have a System Management Bus. There are a lot of +devices which can be connected to a SMBus; the most notable are modern +memory chips with EEPROM memories and chips for hardware monitoring. + +Because the SMBus is just a special case of the generalized I2C bus, we +can simulate the SMBus protocol on plain I2C busses. The reverse is +regretfully impossible. + + +Terminology +=========== + +When we talk about I2C, we use the following terms: + Bus -> Algorithm + Adapter + Device -> Driver + Client + +An Algorithm driver contains general code that can be used for a whole class +of I2C adapters. Each specific adapter driver depends on one algorithm +driver. +A Driver driver (yes, this sounds ridiculous, sorry) contains the general +code to access some type of device. Each detected device gets its own +data in the Client structure. Usually, Driver and Client are more closely +integrated than Algorithm and Adapter. + +For a given configuration, you will need a driver for your I2C bus (usually +a separate Adapter and Algorithm driver), and drivers for your I2C devices +(usually one driver for each device). There are no I2C device drivers +in this package. See the lm_sensors project http://www.lm-sensors.nu +for device drivers. + + +Included Bus Drivers +==================== +Note that only stable drivers are patched into the kernel by 'mkpatch'. + + +Base modules +------------ + +i2c-core: The basic I2C code, including the /proc/bus/i2c* interface +i2c-dev: The /dev/i2c-* interface +i2c-proc: The /proc/sys/dev/sensors interface for device (client) drivers + +Algorithm drivers +----------------- + +i2c-algo-8xx: An algorithm for CPM's I2C device in Motorola 8xx processors (NOT BUILT BY DEFAULT) +i2c-algo-bit: A bit-banging algorithm +i2c-algo-pcf: A PCF 8584 style algorithm +i2c-algo-ibm_ocp: An algorithm for the I2C device in IBM 4xx processors (NOT BUILT BY DEFAULT) + +Adapter drivers +--------------- + +i2c-elektor: Elektor ISA card (uses i2c-algo-pcf) +i2c-elv: ELV parallel port adapter (uses i2c-algo-bit) +i2c-pcf-epp: PCF8584 on a EPP parallel port (uses i2c-algo-pcf) (NOT mkpatched) +i2c-philips-par: Philips style parallel port adapter (uses i2c-algo-bit) +i2c-adap-ibm_ocp: IBM 4xx processor I2C device (uses i2c-algo-ibm_ocp) (NOT BUILT BY DEFAULT) +i2c-pport: Primitive parallel port adapter (uses i2c-algo-bit) +i2c-rpx: RPX board Motorola 8xx I2C device (uses i2c-algo-8xx) (NOT BUILT BY DEFAULT) +i2c-velleman: Velleman K8000 parallel port adapter (uses i2c-algo-bit) + diff --git a/Documentation/i2c/sysfs-interface b/Documentation/i2c/sysfs-interface new file mode 100644 index 000000000000..346400519d0d --- /dev/null +++ b/Documentation/i2c/sysfs-interface @@ -0,0 +1,274 @@ +Naming and data format standards for sysfs files +------------------------------------------------ + +The libsensors library offers an interface to the raw sensors data +through the sysfs interface. See libsensors documentation and source for +more further information. As of writing this document, libsensors +(from lm_sensors 2.8.3) is heavily chip-dependant. Adding or updating +support for any given chip requires modifying the library's code. +This is because libsensors was written for the procfs interface +older kernel modules were using, which wasn't standardized enough. +Recent versions of libsensors (from lm_sensors 2.8.2 and later) have +support for the sysfs interface, though. + +The new sysfs interface was designed to be as chip-independant as +possible. + +Note that motherboards vary widely in the connections to sensor chips. +There is no standard that ensures, for example, that the second +temperature sensor is connected to the CPU, or that the second fan is on +the CPU. Also, some values reported by the chips need some computation +before they make full sense. For example, most chips can only measure +voltages between 0 and +4V. Other voltages are scaled back into that +range using external resistors. Since the values of these resistors +can change from motherboard to motherboard, the conversions cannot be +hard coded into the driver and have to be done in user space. + +For this reason, even if we aim at a chip-independant libsensors, it will +still require a configuration file (e.g. /etc/sensors.conf) for proper +values conversion, labeling of inputs and hiding of unused inputs. + +An alternative method that some programs use is to access the sysfs +files directly. This document briefly describes the standards that the +drivers follow, so that an application program can scan for entries and +access this data in a simple and consistent way. That said, such programs +will have to implement conversion, labeling and hiding of inputs. For +this reason, it is still not recommended to bypass the library. + +If you are developing a userspace application please send us feedback on +this standard. + +Note that this standard isn't completely established yet, so it is subject +to changes, even important ones. One more reason to use the library instead +of accessing sysfs files directly. + +Each chip gets its own directory in the sysfs /sys/devices tree. To +find all sensor chips, it is easier to follow the symlinks from +/sys/i2c/devices/ + +All sysfs values are fixed point numbers. To get the true value of some +of the values, you should divide by the specified value. + +There is only one value per file, unlike the older /proc specification. +The common scheme for files naming is: <type><number>_<item>. Usual +types for sensor chips are "in" (voltage), "temp" (temperature) and +"fan" (fan). Usual items are "input" (measured value), "max" (high +threshold, "min" (low threshold). Numbering usually starts from 1, +except for voltages which start from 0 (because most data sheets use +this). A number is always used for elements that can be present more +than once, even if there is a single element of the given type on the +specific chip. Other files do not refer to a specific element, so +they have a simple name, and no number. + +Alarms are direct indications read from the chips. The drivers do NOT +make comparisons of readings to thresholds. This allows violations +between readings to be caught and alarmed. The exact definition of an +alarm (for example, whether a threshold must be met or must be exceeded +to cause an alarm) is chip-dependent. + + +------------------------------------------------------------------------- + +************ +* Voltages * +************ + +in[0-8]_min Voltage min value. + Unit: millivolt + Read/Write + +in[0-8]_max Voltage max value. + Unit: millivolt + Read/Write + +in[0-8]_input Voltage input value. + Unit: millivolt + Read only + Actual voltage depends on the scaling resistors on the + motherboard, as recommended in the chip datasheet. + This varies by chip and by motherboard. + Because of this variation, values are generally NOT scaled + by the chip driver, and must be done by the application. + However, some drivers (notably lm87 and via686a) + do scale, with various degrees of success. + These drivers will output the actual voltage. + + Typical usage: + in0_* CPU #1 voltage (not scaled) + in1_* CPU #2 voltage (not scaled) + in2_* 3.3V nominal (not scaled) + in3_* 5.0V nominal (scaled) + in4_* 12.0V nominal (scaled) + in5_* -12.0V nominal (scaled) + in6_* -5.0V nominal (scaled) + in7_* varies + in8_* varies + +cpu[0-1]_vid CPU core reference voltage. + Unit: millivolt + Read only. + Not always correct. + +vrm Voltage Regulator Module version number. + Read only. + Two digit number, first is major version, second is + minor version. + Affects the way the driver calculates the CPU core reference + voltage from the vid pins. + + +******** +* Fans * +******** + +fan[1-3]_min Fan minimum value + Unit: revolution/min (RPM) + Read/Write. + +fan[1-3]_input Fan input value. + Unit: revolution/min (RPM) + Read only. + +fan[1-3]_div Fan divisor. + Integer value in powers of two (1, 2, 4, 8, 16, 32, 64, 128). + Some chips only support values 1, 2, 4 and 8. + Note that this is actually an internal clock divisor, which + affects the measurable speed range, not the read value. + +******* +* PWM * +******* + +pwm[1-3] Pulse width modulation fan control. + Integer value in the range 0 to 255 + Read/Write + 255 is max or 100%. + +pwm[1-3]_enable + Switch PWM on and off. + Not always present even if fan*_pwm is. + 0 to turn off + 1 to turn on in manual mode + 2 to turn on in automatic mode + Read/Write + +pwm[1-*]_auto_channels_temp + Select which temperature channels affect this PWM output in + auto mode. Bitfield, 1 is temp1, 2 is temp2, 4 is temp3 etc... + Which values are possible depend on the chip used. + +pwm[1-*]_auto_point[1-*]_pwm +pwm[1-*]_auto_point[1-*]_temp +pwm[1-*]_auto_point[1-*]_temp_hyst + Define the PWM vs temperature curve. Number of trip points is + chip-dependent. Use this for chips which associate trip points + to PWM output channels. + +OR + +temp[1-*]_auto_point[1-*]_pwm +temp[1-*]_auto_point[1-*]_temp +temp[1-*]_auto_point[1-*]_temp_hyst + Define the PWM vs temperature curve. Number of trip points is + chip-dependent. Use this for chips which associate trip points + to temperature channels. + + +**************** +* Temperatures * +**************** + +temp[1-3]_type Sensor type selection. + Integers 1, 2, 3 or thermistor Beta value (3435) + Read/Write. + 1: PII/Celeron Diode + 2: 3904 transistor + 3: thermal diode + Not all types are supported by all chips + +temp[1-4]_max Temperature max value. + Unit: millidegree Celcius + Read/Write value. + +temp[1-3]_min Temperature min value. + Unit: millidegree Celcius + Read/Write value. + +temp[1-3]_max_hyst + Temperature hysteresis value for max limit. + Unit: millidegree Celcius + Must be reported as an absolute temperature, NOT a delta + from the max value. + Read/Write value. + +temp[1-4]_input Temperature input value. + Unit: millidegree Celcius + Read only value. + +temp[1-4]_crit Temperature critical value, typically greater than + corresponding temp_max values. + Unit: millidegree Celcius + Read/Write value. + +temp[1-2]_crit_hyst + Temperature hysteresis value for critical limit. + Unit: millidegree Celcius + Must be reported as an absolute temperature, NOT a delta + from the critical value. + Read/Write value. + + If there are multiple temperature sensors, temp1_* is + generally the sensor inside the chip itself, + reported as "motherboard temperature". temp2_* to + temp4_* are generally sensors external to the chip + itself, for example the thermal diode inside the CPU or + a thermistor nearby. + + +************ +* Currents * +************ + +Note that no known chip provides current measurements as of writing, +so this part is theoretical, so to say. + +curr[1-n]_max Current max value + Unit: milliampere + Read/Write. + +curr[1-n]_min Current min value. + Unit: milliampere + Read/Write. + +curr[1-n]_input Current input value + Unit: milliampere + Read only. + + +********* +* Other * +********* + +alarms Alarm bitmask. + Read only. + Integer representation of one to four bytes. + A '1' bit means an alarm. + Chips should be programmed for 'comparator' mode so that + the alarm will 'come back' after you read the register + if it is still valid. + Generally a direct representation of a chip's internal + alarm registers; there is no standard for the position + of individual bits. + Bits are defined in kernel/include/sensors.h. + +beep_enable Beep/interrupt enable + 0 to disable. + 1 to enable. + Read/Write + +beep_mask Bitmask for beep. + Same format as 'alarms' with the same bit locations. + Read/Write + +eeprom Raw EEPROM data in binary form. + Read only. diff --git a/Documentation/i2c/ten-bit-addresses b/Documentation/i2c/ten-bit-addresses new file mode 100644 index 000000000000..200074f81360 --- /dev/null +++ b/Documentation/i2c/ten-bit-addresses @@ -0,0 +1,22 @@ +The I2C protocol knows about two kinds of device addresses: normal 7 bit +addresses, and an extended set of 10 bit addresses. The sets of addresses +do not intersect: the 7 bit address 0x10 is not the same as the 10 bit +address 0x10 (though a single device could respond to both of them). You +select a 10 bit address by adding an extra byte after the address +byte: + S Addr7 Rd/Wr .... +becomes + S 11110 Addr10 Rd/Wr +S is the start bit, Rd/Wr the read/write bit, and if you count the number +of bits, you will see the there are 8 after the S bit for 7 bit addresses, +and 16 after the S bit for 10 bit addresses. + +WARNING! The current 10 bit address support is EXPERIMENTAL. There are +several places in the code that will cause SEVERE PROBLEMS with 10 bit +addresses, even though there is some basic handling and hooks. Also, +almost no supported adapter handles the 10 bit addresses correctly. + +As soon as a real 10 bit address device is spotted 'in the wild', we +can and will add proper support. Right now, 10 bit address devices +are defined by the I2C protocol, but we have never seen a single device +which supports them. diff --git a/Documentation/i2c/writing-clients b/Documentation/i2c/writing-clients new file mode 100644 index 000000000000..ad27511e3c7d --- /dev/null +++ b/Documentation/i2c/writing-clients @@ -0,0 +1,816 @@ +This is a small guide for those who want to write kernel drivers for I2C +or SMBus devices. + +To set up a driver, you need to do several things. Some are optional, and +some things can be done slightly or completely different. Use this as a +guide, not as a rule book! + + +General remarks +=============== + +Try to keep the kernel namespace as clean as possible. The best way to +do this is to use a unique prefix for all global symbols. This is +especially important for exported symbols, but it is a good idea to do +it for non-exported symbols too. We will use the prefix `foo_' in this +tutorial, and `FOO_' for preprocessor variables. + + +The driver structure +==================== + +Usually, you will implement a single driver structure, and instantiate +all clients from it. Remember, a driver structure contains general access +routines, a client structure specific information like the actual I2C +address. + +static struct i2c_driver foo_driver = { + .owner = THIS_MODULE, + .name = "Foo version 2.3 driver", + .id = I2C_DRIVERID_FOO, /* from i2c-id.h, optional */ + .flags = I2C_DF_NOTIFY, + .attach_adapter = &foo_attach_adapter, + .detach_client = &foo_detach_client, + .command = &foo_command /* may be NULL */ +} + +The name can be chosen freely, and may be upto 40 characters long. Please +use something descriptive here. + +If used, the id should be a unique ID. The range 0xf000 to 0xffff is +reserved for local use, and you can use one of those until you start +distributing the driver, at which time you should contact the i2c authors +to get your own ID(s). Note that most of the time you don't need an ID +at all so you can just omit it. + +Don't worry about the flags field; just put I2C_DF_NOTIFY into it. This +means that your driver will be notified when new adapters are found. +This is almost always what you want. + +All other fields are for call-back functions which will be explained +below. + +There use to be two additional fields in this structure, inc_use et dec_use, +for module usage count, but these fields were obsoleted and removed. + + +Extra client data +================= + +The client structure has a special `data' field that can point to any +structure at all. You can use this to keep client-specific data. You +do not always need this, but especially for `sensors' drivers, it can +be very useful. + +An example structure is below. + + struct foo_data { + struct semaphore lock; /* For ISA access in `sensors' drivers. */ + int sysctl_id; /* To keep the /proc directory entry for + `sensors' drivers. */ + enum chips type; /* To keep the chips type for `sensors' drivers. */ + + /* Because the i2c bus is slow, it is often useful to cache the read + information of a chip for some time (for example, 1 or 2 seconds). + It depends of course on the device whether this is really worthwhile + or even sensible. */ + struct semaphore update_lock; /* When we are reading lots of information, + another process should not update the + below information */ + char valid; /* != 0 if the following fields are valid. */ + unsigned long last_updated; /* In jiffies */ + /* Add the read information here too */ + }; + + +Accessing the client +==================== + +Let's say we have a valid client structure. At some time, we will need +to gather information from the client, or write new information to the +client. How we will export this information to user-space is less +important at this moment (perhaps we do not need to do this at all for +some obscure clients). But we need generic reading and writing routines. + +I have found it useful to define foo_read and foo_write function for this. +For some cases, it will be easier to call the i2c functions directly, +but many chips have some kind of register-value idea that can easily +be encapsulated. Also, some chips have both ISA and I2C interfaces, and +it useful to abstract from this (only for `sensors' drivers). + +The below functions are simple examples, and should not be copied +literally. + + int foo_read_value(struct i2c_client *client, u8 reg) + { + if (reg < 0x10) /* byte-sized register */ + return i2c_smbus_read_byte_data(client,reg); + else /* word-sized register */ + return i2c_smbus_read_word_data(client,reg); + } + + int foo_write_value(struct i2c_client *client, u8 reg, u16 value) + { + if (reg == 0x10) /* Impossible to write - driver error! */ { + return -1; + else if (reg < 0x10) /* byte-sized register */ + return i2c_smbus_write_byte_data(client,reg,value); + else /* word-sized register */ + return i2c_smbus_write_word_data(client,reg,value); + } + +For sensors code, you may have to cope with ISA registers too. Something +like the below often works. Note the locking! + + int foo_read_value(struct i2c_client *client, u8 reg) + { + int res; + if (i2c_is_isa_client(client)) { + down(&(((struct foo_data *) (client->data)) -> lock)); + outb_p(reg,client->addr + FOO_ADDR_REG_OFFSET); + res = inb_p(client->addr + FOO_DATA_REG_OFFSET); + up(&(((struct foo_data *) (client->data)) -> lock)); + return res; + } else + return i2c_smbus_read_byte_data(client,reg); + } + +Writing is done the same way. + + +Probing and attaching +===================== + +Most i2c devices can be present on several i2c addresses; for some this +is determined in hardware (by soldering some chip pins to Vcc or Ground), +for others this can be changed in software (by writing to specific client +registers). Some devices are usually on a specific address, but not always; +and some are even more tricky. So you will probably need to scan several +i2c addresses for your clients, and do some sort of detection to see +whether it is actually a device supported by your driver. + +To give the user a maximum of possibilities, some default module parameters +are defined to help determine what addresses are scanned. Several macros +are defined in i2c.h to help you support them, as well as a generic +detection algorithm. + +You do not have to use this parameter interface; but don't try to use +function i2c_probe() (or i2c_detect()) if you don't. + +NOTE: If you want to write a `sensors' driver, the interface is slightly + different! See below. + + + +Probing classes (i2c) +--------------------- + +All parameters are given as lists of unsigned 16-bit integers. Lists are +terminated by I2C_CLIENT_END. +The following lists are used internally: + + normal_i2c: filled in by the module writer. + A list of I2C addresses which should normally be examined. + normal_i2c_range: filled in by the module writer. + A list of pairs of I2C addresses, each pair being an inclusive range of + addresses which should normally be examined. + probe: insmod parameter. + A list of pairs. The first value is a bus number (-1 for any I2C bus), + the second is the address. These addresses are also probed, as if they + were in the 'normal' list. + probe_range: insmod parameter. + A list of triples. The first value is a bus number (-1 for any I2C bus), + the second and third are addresses. These form an inclusive range of + addresses that are also probed, as if they were in the 'normal' list. + ignore: insmod parameter. + A list of pairs. The first value is a bus number (-1 for any I2C bus), + the second is the I2C address. These addresses are never probed. + This parameter overrules 'normal' and 'probe', but not the 'force' lists. + ignore_range: insmod parameter. + A list of triples. The first value is a bus number (-1 for any I2C bus), + the second and third are addresses. These form an inclusive range of + I2C addresses that are never probed. + This parameter overrules 'normal' and 'probe', but not the 'force' lists. + force: insmod parameter. + A list of pairs. The first value is a bus number (-1 for any I2C bus), + the second is the I2C address. A device is blindly assumed to be on + the given address, no probing is done. + +Fortunately, as a module writer, you just have to define the `normal' +and/or `normal_range' parameters. The complete declaration could look +like this: + + /* Scan 0x20 to 0x2f, 0x37, and 0x40 to 0x4f */ + static unsigned short normal_i2c[] = { 0x37,I2C_CLIENT_END }; + static unsigned short normal_i2c_range[] = { 0x20, 0x2f, 0x40, 0x4f, + I2C_CLIENT_END }; + + /* Magic definition of all other variables and things */ + I2C_CLIENT_INSMOD; + +Note that you *have* to call the two defined variables `normal_i2c' and +`normal_i2c_range', without any prefix! + + +Probing classes (sensors) +------------------------- + +If you write a `sensors' driver, you use a slightly different interface. +As well as I2C addresses, we have to cope with ISA addresses. Also, we +use a enum of chip types. Don't forget to include `sensors.h'. + +The following lists are used internally. They are all lists of integers. + + normal_i2c: filled in by the module writer. Terminated by SENSORS_I2C_END. + A list of I2C addresses which should normally be examined. + normal_i2c_range: filled in by the module writer. Terminated by + SENSORS_I2C_END + A list of pairs of I2C addresses, each pair being an inclusive range of + addresses which should normally be examined. + normal_isa: filled in by the module writer. Terminated by SENSORS_ISA_END. + A list of ISA addresses which should normally be examined. + normal_isa_range: filled in by the module writer. Terminated by + SENSORS_ISA_END + A list of triples. The first two elements are ISA addresses, being an + range of addresses which should normally be examined. The third is the + modulo parameter: only addresses which are 0 module this value relative + to the first address of the range are actually considered. + probe: insmod parameter. Initialize this list with SENSORS_I2C_END values. + A list of pairs. The first value is a bus number (SENSORS_ISA_BUS for + the ISA bus, -1 for any I2C bus), the second is the address. These + addresses are also probed, as if they were in the 'normal' list. + probe_range: insmod parameter. Initialize this list with SENSORS_I2C_END + values. + A list of triples. The first value is a bus number (SENSORS_ISA_BUS for + the ISA bus, -1 for any I2C bus), the second and third are addresses. + These form an inclusive range of addresses that are also probed, as + if they were in the 'normal' list. + ignore: insmod parameter. Initialize this list with SENSORS_I2C_END values. + A list of pairs. The first value is a bus number (SENSORS_ISA_BUS for + the ISA bus, -1 for any I2C bus), the second is the I2C address. These + addresses are never probed. This parameter overrules 'normal' and + 'probe', but not the 'force' lists. + ignore_range: insmod parameter. Initialize this list with SENSORS_I2C_END + values. + A list of triples. The first value is a bus number (SENSORS_ISA_BUS for + the ISA bus, -1 for any I2C bus), the second and third are addresses. + These form an inclusive range of I2C addresses that are never probed. + This parameter overrules 'normal' and 'probe', but not the 'force' lists. + +Also used is a list of pointers to sensors_force_data structures: + force_data: insmod parameters. A list, ending with an element of which + the force field is NULL. + Each element contains the type of chip and a list of pairs. + The first value is a bus number (SENSORS_ISA_BUS for the ISA bus, + -1 for any I2C bus), the second is the address. + These are automatically translated to insmod variables of the form + force_foo. + +So we have a generic insmod variabled `force', and chip-specific variables +`force_CHIPNAME'. + +Fortunately, as a module writer, you just have to define the `normal' +and/or `normal_range' parameters, and define what chip names are used. +The complete declaration could look like this: + /* Scan i2c addresses 0x20 to 0x2f, 0x37, and 0x40 to 0x4f + static unsigned short normal_i2c[] = {0x37,SENSORS_I2C_END}; + static unsigned short normal_i2c_range[] = {0x20,0x2f,0x40,0x4f, + SENSORS_I2C_END}; + /* Scan ISA address 0x290 */ + static unsigned int normal_isa[] = {0x0290,SENSORS_ISA_END}; + static unsigned int normal_isa_range[] = {SENSORS_ISA_END}; + + /* Define chips foo and bar, as well as all module parameters and things */ + SENSORS_INSMOD_2(foo,bar); + +If you have one chip, you use macro SENSORS_INSMOD_1(chip), if you have 2 +you use macro SENSORS_INSMOD_2(chip1,chip2), etc. If you do not want to +bother with chip types, you can use SENSORS_INSMOD_0. + +A enum is automatically defined as follows: + enum chips { any_chip, chip1, chip2, ... } + + +Attaching to an adapter +----------------------- + +Whenever a new adapter is inserted, or for all adapters if the driver is +being registered, the callback attach_adapter() is called. Now is the +time to determine what devices are present on the adapter, and to register +a client for each of them. + +The attach_adapter callback is really easy: we just call the generic +detection function. This function will scan the bus for us, using the +information as defined in the lists explained above. If a device is +detected at a specific address, another callback is called. + + int foo_attach_adapter(struct i2c_adapter *adapter) + { + return i2c_probe(adapter,&addr_data,&foo_detect_client); + } + +For `sensors' drivers, use the i2c_detect function instead: + + int foo_attach_adapter(struct i2c_adapter *adapter) + { + return i2c_detect(adapter,&addr_data,&foo_detect_client); + } + +Remember, structure `addr_data' is defined by the macros explained above, +so you do not have to define it yourself. + +The i2c_probe or i2c_detect function will call the foo_detect_client +function only for those i2c addresses that actually have a device on +them (unless a `force' parameter was used). In addition, addresses that +are already in use (by some other registered client) are skipped. + + +The detect client function +-------------------------- + +The detect client function is called by i2c_probe or i2c_detect. +The `kind' parameter contains 0 if this call is due to a `force' +parameter, and -1 otherwise (for i2c_detect, it contains 0 if +this call is due to the generic `force' parameter, and the chip type +number if it is due to a specific `force' parameter). + +Below, some things are only needed if this is a `sensors' driver. Those +parts are between /* SENSORS ONLY START */ and /* SENSORS ONLY END */ +markers. + +This function should only return an error (any value != 0) if there is +some reason why no more detection should be done anymore. If the +detection just fails for this address, return 0. + +For now, you can ignore the `flags' parameter. It is there for future use. + + int foo_detect_client(struct i2c_adapter *adapter, int address, + unsigned short flags, int kind) + { + int err = 0; + int i; + struct i2c_client *new_client; + struct foo_data *data; + const char *client_name = ""; /* For non-`sensors' drivers, put the real + name here! */ + + /* Let's see whether this adapter can support what we need. + Please substitute the things you need here! + For `sensors' drivers, add `! is_isa &&' to the if statement */ + if (!i2c_check_functionality(adapter,I2C_FUNC_SMBUS_WORD_DATA | + I2C_FUNC_SMBUS_WRITE_BYTE)) + goto ERROR0; + + /* SENSORS ONLY START */ + const char *type_name = ""; + int is_isa = i2c_is_isa_adapter(adapter); + + if (is_isa) { + + /* If this client can't be on the ISA bus at all, we can stop now + (call `goto ERROR0'). But for kicks, we will assume it is all + right. */ + + /* Discard immediately if this ISA range is already used */ + if (check_region(address,FOO_EXTENT)) + goto ERROR0; + + /* Probe whether there is anything on this address. + Some example code is below, but you will have to adapt this + for your own driver */ + + if (kind < 0) /* Only if no force parameter was used */ { + /* We may need long timeouts at least for some chips. */ + #define REALLY_SLOW_IO + i = inb_p(address + 1); + if (inb_p(address + 2) != i) + goto ERROR0; + if (inb_p(address + 3) != i) + goto ERROR0; + if (inb_p(address + 7) != i) + goto ERROR0; + #undef REALLY_SLOW_IO + + /* Let's just hope nothing breaks here */ + i = inb_p(address + 5) & 0x7f; + outb_p(~i & 0x7f,address+5); + if ((inb_p(address + 5) & 0x7f) != (~i & 0x7f)) { + outb_p(i,address+5); + return 0; + } + } + } + + /* SENSORS ONLY END */ + + /* OK. For now, we presume we have a valid client. We now create the + client structure, even though we cannot fill it completely yet. + But it allows us to access several i2c functions safely */ + + /* Note that we reserve some space for foo_data too. If you don't + need it, remove it. We do it here to help to lessen memory + fragmentation. */ + if (! (new_client = kmalloc(sizeof(struct i2c_client) + + sizeof(struct foo_data), + GFP_KERNEL))) { + err = -ENOMEM; + goto ERROR0; + } + + /* This is tricky, but it will set the data to the right value. */ + client->data = new_client + 1; + data = (struct foo_data *) (client->data); + + new_client->addr = address; + new_client->data = data; + new_client->adapter = adapter; + new_client->driver = &foo_driver; + new_client->flags = 0; + + /* Now, we do the remaining detection. If no `force' parameter is used. */ + + /* First, the generic detection (if any), that is skipped if any force + parameter was used. */ + if (kind < 0) { + /* The below is of course bogus */ + if (foo_read(new_client,FOO_REG_GENERIC) != FOO_GENERIC_VALUE) + goto ERROR1; + } + + /* SENSORS ONLY START */ + + /* Next, specific detection. This is especially important for `sensors' + devices. */ + + /* Determine the chip type. Not needed if a `force_CHIPTYPE' parameter + was used. */ + if (kind <= 0) { + i = foo_read(new_client,FOO_REG_CHIPTYPE); + if (i == FOO_TYPE_1) + kind = chip1; /* As defined in the enum */ + else if (i == FOO_TYPE_2) + kind = chip2; + else { + printk("foo: Ignoring 'force' parameter for unknown chip at " + "adapter %d, address 0x%02x\n",i2c_adapter_id(adapter),address); + goto ERROR1; + } + } + + /* Now set the type and chip names */ + if (kind == chip1) { + type_name = "chip1"; /* For /proc entry */ + client_name = "CHIP 1"; + } else if (kind == chip2) { + type_name = "chip2"; /* For /proc entry */ + client_name = "CHIP 2"; + } + + /* Reserve the ISA region */ + if (is_isa) + request_region(address,FOO_EXTENT,type_name); + + /* SENSORS ONLY END */ + + /* Fill in the remaining client fields. */ + strcpy(new_client->name,client_name); + + /* SENSORS ONLY BEGIN */ + data->type = kind; + /* SENSORS ONLY END */ + + data->valid = 0; /* Only if you use this field */ + init_MUTEX(&data->update_lock); /* Only if you use this field */ + + /* Any other initializations in data must be done here too. */ + + /* Tell the i2c layer a new client has arrived */ + if ((err = i2c_attach_client(new_client))) + goto ERROR3; + + /* SENSORS ONLY BEGIN */ + /* Register a new directory entry with module sensors. See below for + the `template' structure. */ + if ((i = i2c_register_entry(new_client, type_name, + foo_dir_table_template,THIS_MODULE)) < 0) { + err = i; + goto ERROR4; + } + data->sysctl_id = i; + + /* SENSORS ONLY END */ + + /* This function can write default values to the client registers, if + needed. */ + foo_init_client(new_client); + return 0; + + /* OK, this is not exactly good programming practice, usually. But it is + very code-efficient in this case. */ + + ERROR4: + i2c_detach_client(new_client); + ERROR3: + ERROR2: + /* SENSORS ONLY START */ + if (is_isa) + release_region(address,FOO_EXTENT); + /* SENSORS ONLY END */ + ERROR1: + kfree(new_client); + ERROR0: + return err; + } + + +Removing the client +=================== + +The detach_client call back function is called when a client should be +removed. It may actually fail, but only when panicking. This code is +much simpler than the attachment code, fortunately! + + int foo_detach_client(struct i2c_client *client) + { + int err,i; + + /* SENSORS ONLY START */ + /* Deregister with the `i2c-proc' module. */ + i2c_deregister_entry(((struct lm78_data *)(client->data))->sysctl_id); + /* SENSORS ONLY END */ + + /* Try to detach the client from i2c space */ + if ((err = i2c_detach_client(client))) { + printk("foo.o: Client deregistration failed, client not detached.\n"); + return err; + } + + /* SENSORS ONLY START */ + if i2c_is_isa_client(client) + release_region(client->addr,LM78_EXTENT); + /* SENSORS ONLY END */ + + kfree(client); /* Frees client data too, if allocated at the same time */ + return 0; + } + + +Initializing the module or kernel +================================= + +When the kernel is booted, or when your foo driver module is inserted, +you have to do some initializing. Fortunately, just attaching (registering) +the driver module is usually enough. + + /* Keep track of how far we got in the initialization process. If several + things have to initialized, and we fail halfway, only those things + have to be cleaned up! */ + static int __initdata foo_initialized = 0; + + static int __init foo_init(void) + { + int res; + printk("foo version %s (%s)\n",FOO_VERSION,FOO_DATE); + + if ((res = i2c_add_driver(&foo_driver))) { + printk("foo: Driver registration failed, module not inserted.\n"); + foo_cleanup(); + return res; + } + foo_initialized ++; + return 0; + } + + void foo_cleanup(void) + { + if (foo_initialized == 1) { + if ((res = i2c_del_driver(&foo_driver))) { + printk("foo: Driver registration failed, module not removed.\n"); + return; + } + foo_initialized --; + } + } + + /* Substitute your own name and email address */ + MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>" + MODULE_DESCRIPTION("Driver for Barf Inc. Foo I2C devices"); + + module_init(foo_init); + module_exit(foo_cleanup); + +Note that some functions are marked by `__init', and some data structures +by `__init_data'. Hose functions and structures can be removed after +kernel booting (or module loading) is completed. + +Command function +================ + +A generic ioctl-like function call back is supported. You will seldom +need this. You may even set it to NULL. + + /* No commands defined */ + int foo_command(struct i2c_client *client, unsigned int cmd, void *arg) + { + return 0; + } + + +Sending and receiving +===================== + +If you want to communicate with your device, there are several functions +to do this. You can find all of them in i2c.h. + +If you can choose between plain i2c communication and SMBus level +communication, please use the last. All adapters understand SMBus level +commands, but only some of them understand plain i2c! + + +Plain i2c communication +----------------------- + + extern int i2c_master_send(struct i2c_client *,const char* ,int); + extern int i2c_master_recv(struct i2c_client *,char* ,int); + +These routines read and write some bytes from/to a client. The client +contains the i2c address, so you do not have to include it. The second +parameter contains the bytes the read/write, the third the length of the +buffer. Returned is the actual number of bytes read/written. + + extern int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msg, + int num); + +This sends a series of messages. Each message can be a read or write, +and they can be mixed in any way. The transactions are combined: no +stop bit is sent between transaction. The i2c_msg structure contains +for each message the client address, the number of bytes of the message +and the message data itself. + +You can read the file `i2c-protocol' for more information about the +actual i2c protocol. + + +SMBus communication +------------------- + + extern s32 i2c_smbus_xfer (struct i2c_adapter * adapter, u16 addr, + unsigned short flags, + char read_write, u8 command, int size, + union i2c_smbus_data * data); + + This is the generic SMBus function. All functions below are implemented + in terms of it. Never use this function directly! + + + extern s32 i2c_smbus_write_quick(struct i2c_client * client, u8 value); + extern s32 i2c_smbus_read_byte(struct i2c_client * client); + extern s32 i2c_smbus_write_byte(struct i2c_client * client, u8 value); + extern s32 i2c_smbus_read_byte_data(struct i2c_client * client, u8 command); + extern s32 i2c_smbus_write_byte_data(struct i2c_client * client, + u8 command, u8 value); + extern s32 i2c_smbus_read_word_data(struct i2c_client * client, u8 command); + extern s32 i2c_smbus_write_word_data(struct i2c_client * client, + u8 command, u16 value); + extern s32 i2c_smbus_write_block_data(struct i2c_client * client, + u8 command, u8 length, + u8 *values); + +These ones were removed in Linux 2.6.10 because they had no users, but could +be added back later if needed: + + extern s32 i2c_smbus_read_i2c_block_data(struct i2c_client * client, + u8 command, u8 *values); + extern s32 i2c_smbus_read_block_data(struct i2c_client * client, + u8 command, u8 *values); + extern s32 i2c_smbus_write_i2c_block_data(struct i2c_client * client, + u8 command, u8 length, + u8 *values); + extern s32 i2c_smbus_process_call(struct i2c_client * client, + u8 command, u16 value); + extern s32 i2c_smbus_block_process_call(struct i2c_client *client, + u8 command, u8 length, + u8 *values) + +All these transactions return -1 on failure. The 'write' transactions +return 0 on success; the 'read' transactions return the read value, except +for read_block, which returns the number of values read. The block buffers +need not be longer than 32 bytes. + +You can read the file `smbus-protocol' for more information about the +actual SMBus protocol. + + +General purpose routines +======================== + +Below all general purpose routines are listed, that were not mentioned +before. + + /* This call returns a unique low identifier for each registered adapter, + * or -1 if the adapter was not registered. + */ + extern int i2c_adapter_id(struct i2c_adapter *adap); + + +The sensors sysctl/proc interface +================================= + +This section only applies if you write `sensors' drivers. + +Each sensors driver creates a directory in /proc/sys/dev/sensors for each +registered client. The directory is called something like foo-i2c-4-65. +The sensors module helps you to do this as easily as possible. + +The template +------------ + +You will need to define a ctl_table template. This template will automatically +be copied to a newly allocated structure and filled in where necessary when +you call sensors_register_entry. + +First, I will give an example definition. + static ctl_table foo_dir_table_template[] = { + { FOO_SYSCTL_FUNC1, "func1", NULL, 0, 0644, NULL, &i2c_proc_real, + &i2c_sysctl_real,NULL,&foo_func }, + { FOO_SYSCTL_FUNC2, "func2", NULL, 0, 0644, NULL, &i2c_proc_real, + &i2c_sysctl_real,NULL,&foo_func }, + { FOO_SYSCTL_DATA, "data", NULL, 0, 0644, NULL, &i2c_proc_real, + &i2c_sysctl_real,NULL,&foo_data }, + { 0 } + }; + +In the above example, three entries are defined. They can either be +accessed through the /proc interface, in the /proc/sys/dev/sensors/* +directories, as files named func1, func2 and data, or alternatively +through the sysctl interface, in the appropriate table, with identifiers +FOO_SYSCTL_FUNC1, FOO_SYSCTL_FUNC2 and FOO_SYSCTL_DATA. + +The third, sixth and ninth parameters should always be NULL, and the +fourth should always be 0. The fifth is the mode of the /proc file; +0644 is safe, as the file will be owned by root:root. + +The seventh and eighth parameters should be &i2c_proc_real and +&i2c_sysctl_real if you want to export lists of reals (scaled +integers). You can also use your own function for them, as usual. +Finally, the last parameter is the call-back to gather the data +(see below) if you use the *_proc_real functions. + + +Gathering the data +------------------ + +The call back functions (foo_func and foo_data in the above example) +can be called in several ways; the operation parameter determines +what should be done: + + * If operation == SENSORS_PROC_REAL_INFO, you must return the + magnitude (scaling) in nrels_mag; + * If operation == SENSORS_PROC_REAL_READ, you must read information + from the chip and return it in results. The number of integers + to display should be put in nrels_mag; + * If operation == SENSORS_PROC_REAL_WRITE, you must write the + supplied information to the chip. nrels_mag will contain the number + of integers, results the integers themselves. + +The *_proc_real functions will display the elements as reals for the +/proc interface. If you set the magnitude to 2, and supply 345 for +SENSORS_PROC_REAL_READ, it would display 3.45; and if the user would +write 45.6 to the /proc file, it would be returned as 4560 for +SENSORS_PROC_REAL_WRITE. A magnitude may even be negative! + +An example function: + + /* FOO_FROM_REG and FOO_TO_REG translate between scaled values and + register values. Note the use of the read cache. */ + void foo_in(struct i2c_client *client, int operation, int ctl_name, + int *nrels_mag, long *results) + { + struct foo_data *data = client->data; + int nr = ctl_name - FOO_SYSCTL_FUNC1; /* reduce to 0 upwards */ + + if (operation == SENSORS_PROC_REAL_INFO) + *nrels_mag = 2; + else if (operation == SENSORS_PROC_REAL_READ) { + /* Update the readings cache (if necessary) */ + foo_update_client(client); + /* Get the readings from the cache */ + results[0] = FOO_FROM_REG(data->foo_func_base[nr]); + results[1] = FOO_FROM_REG(data->foo_func_more[nr]); + results[2] = FOO_FROM_REG(data->foo_func_readonly[nr]); + *nrels_mag = 2; + } else if (operation == SENSORS_PROC_REAL_WRITE) { + if (*nrels_mag >= 1) { + /* Update the cache */ + data->foo_base[nr] = FOO_TO_REG(results[0]); + /* Update the chip */ + foo_write_value(client,FOO_REG_FUNC_BASE(nr),data->foo_base[nr]); + } + if (*nrels_mag >= 2) { + /* Update the cache */ + data->foo_more[nr] = FOO_TO_REG(results[1]); + /* Update the chip */ + foo_write_value(client,FOO_REG_FUNC_MORE(nr),data->foo_more[nr]); + } + } + } |