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authorLinus Torvalds <torvalds@linux-foundation.org>2016-12-15 12:56:35 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2016-12-15 12:56:35 -0800
commit8600b697cd4787ac3ce053d48ca7301836fd0c55 (patch)
treeba0771e53ffb66b2c077b54f620d9bb78b43ba79 /Documentation/i2c
parent0ab7b12c49b6fbf2d4d0381374b82935f949be5f (diff)
parent6eb89ef029fe22aee518a9dc75b9ee5d6ef9b3fe (diff)
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Merge branch 'i2c/for-4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux
Pull i2c updates from Wolfram Sang: - the first series of making i2c_device_id optional instead of mandatory (in favor of alternatives like of_device_id). This involves adding a new probe callback (probe_new) which removes some peculiarities I2C had for a long time now. The new probe is matching the other subsystems now and the old one will be removed once all users are converted. It is expected to take a while but there is ongoing interest in that. - SMBus Host Notify introduced 4.9 got refactored. They are now using interrupts instead of the alert callback which solves multiple issues. - new drivers for iMX LowPower I2C, Mellanox CPLD and its I2C mux - significant refactoring for bcm2835 driver - the usual set of driver updates and improvements * 'i2c/for-4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: (46 commits) i2c: fsl-lpi2c: read lpi2c fifo size in probe() i2c: octeon: thunderx: Remove double-check after interrupt i2c: octeon: thunderx: TWSI software reset in recovery i2c: cadence: Allow Cadence I2C to be selected for Cadence Xtensa CPUs i2c: sh_mobile: Add per-Generation fallback bindings i2c: rcar: Add per-Generation fallback bindings i2c: imx-lpi2c: add low power i2c bus driver dt-bindings: i2c: imx-lpi2c: add devicetree bindings i2c: designware-pcidrv: Add 10bit address feature to medfield/merrifield i2c: pxa: Add support for the I2C units found in Armada 3700 i2c: pxa: Add definition of fast and high speed modes via the regs layout dt-bindings: i2c: pxa: Update the documentation for the Armada 3700 i2c: qup: support SMBus block read i2c: qup: add ACPI support i2c: designware: Consolidate default functionality bits i2c: i2c-mux-gpio: update mux with gpiod_set_array_value_cansleep i2c: mux: pca954x: Add ACPI support for pca954x i2c: use an IRQ to report Host Notify events, not alert i2c: i801: remove SMBNTFDDAT reads as they always seem to return 0 i2c: i801: use the BIT() macro for FEATURES_* also ...
Diffstat (limited to 'Documentation/i2c')
-rw-r--r--Documentation/i2c/busses/i2c-mlxcpld47
-rw-r--r--Documentation/i2c/smbus-protocol12
2 files changed, 55 insertions, 4 deletions
diff --git a/Documentation/i2c/busses/i2c-mlxcpld b/Documentation/i2c/busses/i2c-mlxcpld
new file mode 100644
index 000000000000..4e46c440b38d
--- /dev/null
+++ b/Documentation/i2c/busses/i2c-mlxcpld
@@ -0,0 +1,47 @@
+Driver i2c-mlxcpld
+
+Author: Michael Shych <michaelsh@mellanox.com>
+
+This is the Mellanox I2C controller logic, implemented in Lattice CPLD
+device.
+Device supports:
+ - Master mode.
+ - One physical bus.
+ - Polling mode.
+
+This controller is equipped within the next Mellanox systems:
+"msx6710", "msx6720", "msb7700", "msn2700", "msx1410", "msn2410", "msb7800",
+"msn2740", "msn2100".
+
+The next transaction types are supported:
+ - Receive Byte/Block.
+ - Send Byte/Block.
+ - Read Byte/Block.
+ - Write Byte/Block.
+
+Registers:
+CTRL 0x1 - control reg.
+ Resets all the registers.
+HALF_CYC 0x4 - cycle reg.
+ Configure the width of I2C SCL half clock cycle (in 4 LPC_CLK
+ units).
+I2C_HOLD 0x5 - hold reg.
+ OE (output enable) is delayed by value set to this register
+ (in LPC_CLK units)
+CMD 0x6 - command reg.
+ Bit 0, 0 = write, 1 = read.
+ Bits [7:1] - the 7bit Address of the I2C device.
+ It should be written last as it triggers an I2C transaction.
+NUM_DATA 0x7 - data size reg.
+ Number of data bytes to write in read transaction
+NUM_ADDR 0x8 - address reg.
+ Number of address bytes to write in read transaction.
+STATUS 0x9 - status reg.
+ Bit 0 - transaction is completed.
+ Bit 4 - ACK/NACK.
+DATAx 0xa - 0x54 - 68 bytes data buffer regs.
+ For write transaction address is specified in four first bytes
+ (DATA1 - DATA4), data starting from DATA4.
+ For read transactions address is sent in a separate transaction and
+ specified in the four first bytes (DATA0 - DATA3). Data is read
+ starting from DATA0.
diff --git a/Documentation/i2c/smbus-protocol b/Documentation/i2c/smbus-protocol
index 14d4ec1be245..092d474f5843 100644
--- a/Documentation/i2c/smbus-protocol
+++ b/Documentation/i2c/smbus-protocol
@@ -200,10 +200,14 @@ alerting device's address.
[S] [HostAddr] [Wr] A [DevAddr] A [DataLow] A [DataHigh] A [P]
This is implemented in the following way in the Linux kernel:
-* I2C bus drivers which support SMBus Host Notify should call
- i2c_setup_smbus_host_notify() to setup SMBus Host Notify support.
-* I2C drivers for devices which can trigger SMBus Host Notify should implement
- the optional alert() callback.
+* I2C bus drivers which support SMBus Host Notify should report
+ I2C_FUNC_SMBUS_HOST_NOTIFY.
+* I2C bus drivers trigger SMBus Host Notify by a call to
+ i2c_handle_smbus_host_notify().
+* I2C drivers for devices which can trigger SMBus Host Notify will have
+ client->irq assigned to a Host Notify IRQ if noone else specified an other.
+
+There is currently no way to retrieve the data parameter from the client.
Packet Error Checking (PEC)