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path: root/drivers/nfc/trf7970a.c
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* NFC: trf7970a: Correct register settings for 27MHz clockGeoff Lansberry2017-06-281-0/+7
| | | | | | | | | | In prior commits the selected clock frequency does not propagate correctly to what is written to the TRF7970A_MODULATOR_SYS_CLK_CTRL register. Signed-off-by: Geoff Lansberry <geoff@kuvee.com> Acked-by: Mark Greer <mgreer@animalcreek.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* Revert "NFC: trf7970a: Handle extra byte in response to Type 5 RMB commands"Mark Greer2017-06-231-21/+4
| | | | | | | | | | | | | | | | | | | | | | | This reverts commit ab714817d7e891608d31f6996b1e4c43cf2bf342. The original commit was designed to handle a bug in the trf7970a NFC controller where an extra byte was returned in Read Multiple Blocks (RMB) command responses. However, it has become less clear whether it is a bug in the trf7970a or in the tag. In addition, it was assumed that the extra byte was always returned but it turns out that is not always the case. The result is that a byte of good data is trimmed off when the extra byte is not present ultimately causing the neard deamon to fail the read. Since the trf7970a driver does not have the context to know when to trim the byte or not, remove the code from the trf7970a driver all together (and move it up to the neard daemon). This has the added benefit of simplifying the kernel driver and putting the extra complexity into userspace. CC: Rob Herring <robh@kernel.org> CC: devicetree@vger.kernel.org Signed-off-by: Mark Greer <mgreer@animalcreek.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* NFC: trf7970a: fix check of clock frequencies, use && instead of ||Colin Ian King2017-06-221-1/+1
| | | | | | | | | | | | | | The "or" condition (clk_freq != TRF7970A_27MHZ_CLOCK_FREQUENCY) || (clk_freq != TRF7970A_13MHZ_CLOCK_FREQUE) will always be true because clk_freq cannot be equal to two different values at the same time. Use the && operator instead of || to fix this. Detected by CoverityScan, CID#1430468 ("Constant expression result") Fixes: 837eb4d21ecde7 ("NFC: trf7970a: add device tree option for 27MHz clock") Signed-off-by: Colin Ian King <colin.king@canonical.com> Acked-by: Geoff Lansberry <geoff@kuvee.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* NFC: trf7970a: Clean up coding style issuesMark Greer2017-06-181-144/+147
| | | | | | | | | | Clean up coding style issues according to scripts/Lindent. Some scripts/Lindent changes were reverted when it appeared to make the code less readable or when it made the line run over 80 characters. Signed-off-by: Mark Greer <mgreer@animalcreek.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* NFC: trf7970a: Convert to descriptor based GPIO interfaceMark Greer2017-06-181-36/+25
| | | | | | | | | The trf7970a driver uses the deprecated integer-based GPIO consumer interface so convert it to use the new descriptor-based GPIO consumer interface. Signed-off-by: Mark Greer <mgreer@animalcreek.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* NFC: trf7970a: Remove support for 'vin-voltage-override' DT propertyMark Greer2017-06-181-10/+1
| | | | | | | | | | | The 'vin-voltage-override' DT property is used by the trf7970a driver to override the voltage presented to the driver by the regulator subsystem. This is unnecessary as properly specifying the regulator chain via DT properties will accomplish the same thing. Therefore, remove support for 'vin-voltage-override'. Signed-off-by: Mark Greer <mgreer@animalcreek.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* NFC: trf7970a: Remove useless commentMark Greer2017-06-181-1/+1
| | | | | | | | | The last entry in the trf7970a_of_match[] table must be an empty entry to demarcate the end of the table. Currently, there is a comment indicating this but it is obvious so remove the comment. Signed-off-by: Mark Greer <mgreer@animalcreek.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* NFC: trf7970a: Only check 'en2-rf-quirk' if EN2 is specifiedMark Greer2017-06-181-3/+3
| | | | | | | | | | | The quirk indicated by the 'en2-rf-quirk' device tree property is only relevant when there is a GPIO connected to the EN2 pin of the trf7970a. This means we should only check for 'en2-rf-quirk' when EN2 is specified in the 'ti,enable-gpios' property of the device tree. Signed-off-by: Mark Greer <mgreer@animalcreek.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* NFC: trf7970a: Fix inaccurate comment in trf7970a_probe()Mark Greer2017-06-181-1/+1
| | | | | | | | | | As of commit ce69b95ca4e4 ("NFC: Make EN2 pin optional in the TRF7970A driver"), only the GPIO for the 'EN' enable pin needs to be specified in the device tree so update the comments that says both 'EN' and 'EN2' must be specified. Signed-off-by: Mark Greer <mgreer@animalcreek.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* NFC: trf7970a: Don't de-assert EN2 unless it was assertedMark Greer2017-06-181-2/+4
| | | | | | | | | | When the trf7970a part has the bug related to 'en2-rf-quirk', the GPIO connected to the EN2 pin will not be asserted by the driver when powering up so it shouldn't be de-asserted when powering down. Signed-off-by: Mark Greer <mgreer@animalcreek.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* NFC: trf7970a: Add device tree option of 1.8 Volt IO voltageGeoff Lansberry2017-04-051-1/+25
| | | | | | | | | | | | | The TRF7970A has configuration options for supporting hardware designs with 1.8 Volt or 3.3 Volt IO. This commit adds a device tree option, using a fixed regulator binding, for setting the io voltage to match the hardware configuration. If no option is supplied it defaults to 3.3 volt configuration. Acked-by: Rob Herring <robh@kernel.org> Acked-by: Mark Greer <mgreer@animalcreek.com> Signed-off-by: Geoff Lansberry <geoff@kuvee.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* NFC: trf7970a: add device tree option for 27MHz clockGeoff Lansberry2017-04-051-11/+39
| | | | | | | | | | | | The TRF7970A has configuration options to support hardware designs which use a 27.12MHz clock. This commit adds a device tree option 'clock-frequency' to support configuring the this chip for default 13.56MHz clock or the optional 27.12MHz clock. Acked-by: Rob Herring <robh@kernel.org> Acked-by: Mark Greer <mgreer@animalcreek.com> Signed-off-by: Geoff Lansberry <geoff@kuvee.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* NFC: Make EN2 pin optional in the TRF7970A driverGuan Ben2017-04-021-12/+14
| | | | | | | | | | | Make the EN2 pin optional. This is useful for boards, which have this pin fix wired, for example to ground. Acked-by: Rob Herring <robh@kernel.org> Signed-off-by: Guan Ben <ben.guan@cn.bosch.com> Signed-off-by: Mark Jonas <mark.jonas@de.bosch.com> Signed-off-by: Heiko Schocher <hs@denx.de> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* NFC: trf7970a: add TI recommended write of zero to Register 0x18Geoff Lansberry2016-07-041-0/+4
| | | | | Signed-off-by: Geoff Lansberry <geoff@kuvee.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* NFC: trf7970a: use to_spi_deviceGeliang Tang2015-12-291-4/+4
| | | | | | | Use to_spi_device() instead of open-coding it. Signed-off-by: Geliang Tang <geliangtang@163.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* Merge tag 'spi-v4.4' of ↵Linus Torvalds2015-11-051-1/+0
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi Pull spi updates from Mark Brown: "Quite a lot of activity in SPI this cycle, almost all of it in drivers with a few minor improvements and tweaks in the core. - Updates to pxa2xx to support Intel Broxton and multiple chip selects. - Support for big endian in the bcm63xx driver. - Multiple slave support for the mt8173 - New driver for the auxiliary SPI controller in bcm2835 SoCs. - Support for Layerscale SoCs in the Freescale DSPI driver" * tag 'spi-v4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi: (87 commits) spi: pxa2xx: Rework self-initiated platform data creation for non-ACPI spi: pxa2xx: Add support for Intel Broxton spi: pxa2xx: Detect number of enabled Intel LPSS SPI chip select signals spi: pxa2xx: Add output control for multiple Intel LPSS chip selects spi: pxa2xx: Use LPSS prefix for defines that are Intel LPSS specific spi: Add DSPI support for layerscape family spi: ti-qspi: improve ->remove() callback spi/spi-xilinx: Fix race condition on last word read spi: Drop owner assignment from spi_drivers spi: Add THIS_MODULE to spi_driver in SPI core spi: Setup the master controller driver before setting the chipselect spi: dw: replace magic constant by DW_SPI_DR spi: mediatek: mt8173 spi multiple devices support spi: mediatek: handle controller_data in mtk_spi_setup spi: mediatek: remove mtk_spi_config spi: mediatek: Update document devicetree bindings to support multiple devices spi: fix kernel-doc warnings about missing return desc in spi.c spi: fix kernel-doc warnings about missing return desc in spi.h spi: pxa2xx: Align a few defines spi: pxa2xx: Save other reg_cs_ctrl bits when configuring chip select ...
| * spi: Drop owner assignment from spi_driversAndrew F. Davis2015-10-281-1/+0
| | | | | | | | | | | | | | | | | | An spi_driver does not need to set an owner, it will be populated by the driver core. Signed-off-by: Andrew F. Davis <afd@ti.com> Acked-by: Jonathan Cameron <jic23@kernel.org> Signed-off-by: Mark Brown <broonie@kernel.org>
* | NFC: trf7970a: Add OF match tableJavier Martinez Canillas2015-10-191-0/+7
|/ | | | | | | | | | The Documentation/devicetree/bindings/net/nfc/trf7970a.txt DT binding doc lists "ti,trf7970a" as a compatible string but the corresponding driver does not have an OF match table. Add the table to the driver so the SPI core can do an OF style match. Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* NFC: trf7970a: Add NULL check to clear up smatch warningMark Greer2015-08-191-1/+3
| | | | | | | | | Although it should be unnecessary, add a NULL pointer check to trf7970a_send_upstream() to eliminate a smatch warning. Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Mark Greer <mgreer@animalcreek.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* NFC: trf7970a: SDD_EN is bit 5 not bit 3Mark Greer2015-08-191-1/+1
| | | | | | | | | | The SDD_EN bit in the NFC Target Detection Level Register is bit 5 not bit 3 so change the TRF7970A_NFC_TARGET_LEVEL_SDD_EN macro accordingly. Reported-by: Raymond Lei <Raymond.Lei@ecolab.com> Signed-off-by: Mark Greer <mgreer@animalcreek.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* NFC: trf7970a: Handle extra byte in response to Type 5 RMB commandsMark A. Greer2015-06-081-4/+19
| | | | | | | | | | | | | | | | The current versions of the trf7970a has an erratum where it returns an extra byte in the response to 'Read Multiple Block' (RMB) commands. This command is issued to Type 5 tags (i.e., ISO/IEC 15693 tags) by the neard daemon. To handle this, define a new Device Tree property, 't5t-rmb-extra-byte-quirk', which indicates that the associated trf7970a device has this erratum. The trf7970a device driver will then ensure that the response length to RMB commands is reduced by one byte (for devices with the erratum). Signed-off-by: Mark A. Greer <mgreer@animalcreek.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* NFC / PM: Replace CONFIG_PM_RUNTIME with CONFIG_PMRafael J. Wysocki2014-12-151-1/+1
| | | | | | | | | | | After commit b2b49ccbdd54 (PM: Kconfig: Set PM_RUNTIME if PM_SLEEP is selected) PM_RUNTIME is always set if PM is set, so #ifdef blocks depending on CONFIG_PM_RUNTIME may now be changed to depend on CONFIG_PM. Replace CONFIG_PM_RUNTIME with CONFIG_PM in drivers/nfc/trf7970a.c. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* NFC: trf7970a: Unlock mutex before exiting _trf7970a_tg_listen()Mark A. Greer2014-09-241-4/+4
| | | | | | | | | | The recently added _trf7970a_tg_listen() routine has some return paths that don't unlock the mutex that is locked when the routine is entered. Fix this by always unlocking the mutex before returning. Signed-off-by: Mark A. Greer <mgreer@animalcreek.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* NFC: trf7970a: Unlock mutex before exiting trf7970a_irq()Mark A. Greer2014-09-241-2/+3
| | | | | | | | | | Recent changes to trf7970a_irq() added a couple return paths that don't unlock the mutex that is locked when the routine is entered. Fix this by ensuring the mutex is always unlocked before returning. Signed-off-by: Mark A. Greer <mgreer@animalcreek.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* NFC: trf7970a: Remove unnecessary local variable initializationMark A. Greer2014-09-241-1/+1
| | | | | | | | There is no need to initialize the 'ret' variable in trf7970a_resume(). Signed-off-by: Mark A. Greer <mgreer@animalcreek.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* NFC: trf7970a: Remove useless local variableMark A. Greer2014-09-241-2/+1
| | | | | | | | | | The trf7970a_suspend() routine always returns zero so don't use a local return variable to hold the return value. This fixes up a smatch warning. Signed-off-by: Mark A. Greer <mgreer@animalcreek.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* NFC: trf7970a: Add Target Mode Detection SupportMark A. Greer2014-09-071-6/+154
| | | | | | | | | | Add the ability to detect the mode (i.e., RF technology) used by the initiator. The RF technology that was detected can be retrieved by calling the 'tg_get_rf_tech' driver hook. Signed-off-by: Mark A. Greer <mgreer@animalcreek.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* NFC: trf7970a: Add Target Mode SupportMark A. Greer2014-09-071-35/+339
| | | | | | | | | | | | | | | Add target mode support to the trf7970a NFC driver. This effectively enables full Peer-to-Peer support. To handle changing framing between sending a response frame and receiving the subsequent request frame, most of the framing changes take effect in the interrupt handler and not in trf7970a_tg_config_framing(). Signed-off-by: Mark A. Greer <mgreer@animalcreek.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* NFC: trf7970a: Handle timeout values of zeroMark A. Greer2014-09-071-7/+22
| | | | | | | | | | | | | | | | The digital layer can try to send a command with a timeout value of zero (e.g., digital_tg_send_psl_res(). The zero value is used as a flag to indicate that the driver should not expect a response. To handle this, the driver sets an internal timer because it should still get an interrupt with the TX bit set in the IRQ Status Register. When it gets that interrupt, it returns a return value of '0'. If it doesn't get the interrupt before timing out, it returns ETIMEDOUT as usual. Signed-off-by: Mark A. Greer <mgreer@animalcreek.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* NFC: trf7970a: Cancel timer when error encounteredMark A. Greer2014-09-071-0/+2
| | | | | | | | | | | | Some paths leave a timer still running when trf7970a_send_err_upstream() is called. This can cause a timeout to occur in a subsequent transaction making it fail. Fix this by ensuring there is no timer running before sending an error upstream. Signed-off-by: Mark A. Greer <mgreer@animalcreek.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* NFC: trf7970a: Don't turn on RF if there is already an RF fieldMark A. Greer2014-09-071-2/+49
| | | | | | | | | | | | Currently, the trf7970a driver blindly turns on its RF field when configuring its framing. This isn't a good idea if there is already a device generating an RF field. Instead, check if there is already an RF field present before turning on this device's RF field and, if there is, return EBUSY. Signed-off-by: Mark A. Greer <mgreer@animalcreek.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* NFC: trf7970a: trf7970a_init() turns off the RF transmitterMark A. Greer2014-09-071-0/+2
| | | | | | | | | | When trf7970a_init() initializes the trf7970a it implicitly turns off the RF transmitter. Track this by clearing the TRF7970A_CHIP_STATUS_RF_ON bit in the cached trf->chip_status_ctrl. Signed-off-by: Mark A. Greer <mgreer@animalcreek.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* NFC: trf7970a: Don't turn off RF if its already offMark A. Greer2014-09-071-0/+4
| | | | | | | | Don't try to turn off of RF transmitter is its already off. Signed-off-by: Mark A. Greer <mgreer@animalcreek.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* NFC: trf7970a: Add '_in_' to initiator routinesMark A. Greer2014-09-071-4/+4
| | | | | | | | | Rename trf7970a_config_rf_tech() and trf7970a_config_framing() to trf7970a_in_config_rf_tech() and trf7970a_in_config_framing(), respectively to avoid confusion when target support is added. Signed-off-by: Mark A. Greer <mgreer@animalcreek.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* NFC: trf7970a: Delay after initializationMark A. Greer2014-09-071-0/+2
| | | | | | | | | The trf7970a should be given at least 1 ms to completely initialize after the 'Software Init' and 'Idle' commands have been issued. Signed-off-by: Mark A. Greer <mgreer@animalcreek.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* NFC: trf7970a: Add System Suspend/Resume supportMark A. Greer2014-09-071-0/+37
| | | | | | | | | Add system suspend/resume support by gracefully shutting things down when suspending and bringing the device back to full power when resuming. Signed-off-by: Mark A. Greer <mgreer@animalcreek.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* NFC: trf7970a: Create startup and shutdown routinesMark A. Greer2014-09-071-29/+43
| | | | | | | | | | Encapsulate the code to start up and gracefully shutdown the driver and trf7970a device. Doing this makes adding system suspend/resume support easier and the resulting code cleaner. Signed-off-by: Mark A. Greer <mgreer@animalcreek.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* NFC: trf7970a: Don't assume CONFIG_PM_RUNTIME is enabledMark A. Greer2014-09-071-36/+96
| | | | | | | | | | | | | | | | | | The current code assumes that CONFIG_PM_RUNTIME is always defined so it won't power up the trf7970a when it isn't enabled. Fix this by moving the power up/down code from the pm_runtime_resume/suspend routines into their own routines and calling the power up function from the probe routine. This ensures the device is powered up even when CONFIG_PM_RUNTIME is not defined. In order to not power on/off a device that is already powered on/off, create a new state to indicate that the power is off (TRF7970A_ST_PWR_OFF). Signed-off-by: Mark A. Greer <mgreer@animalcreek.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* NFC: trf7970a: Rename TRF7970A_ST_OFF to TRF7970A_ST_RF_OFFMark A. Greer2014-09-071-8/+8
| | | | | | | | | Rename the 'TRF7970A_ST_OFF' state to 'TRF7970A_ST_RF_OFF' to make it clear that this state means that the RF is off and not the entire device. Signed-off-by: Mark A. Greer <mgreer@animalcreek.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* NFC: trf7970a: Return error code when turning on RF failsMark A. Greer2014-09-071-6/+15
| | | | | | | | | | | trf7970a_switch_rf_on() is currently a void function but turning on the RF could fail so it should return a return code. That return code should also be propagated back to the entity that initiated the action. Signed-off-by: Mark A. Greer <mgreer@animalcreek.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* NFC: trf7970a: Ensure no more RX data before completing receiveMark A. Greer2014-09-071-1/+1
| | | | | | | | | | | | | | | | | | Depending on the interrupt status value given by the trf7970a, the driver may not know when a receive operation is complete. To handle this, the driver waits for a period of time in case the trf7970a interrupts it again indicating there are more RX data in the FIFO. It is possible that the timeout will occur when there are RX data in the FIFO but before the trf7970a has generated an interrupt to tell the driver about it. Handle this by calling trf7970a_drain_fifo() (instead of trf7970a_send_upstream() which just passes up the data gathered to far) to check if there are more data in the FIFO. If so, gather that data into the receive buffer. If not, pass the data collected so far upstream as before. Signed-off-by: Mark A. Greer <mgreer@animalcreek.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* NFC: trf7970a: Reread FIFO Status Register when draining FIFOMark A. Greer2014-09-071-0/+15
| | | | | | | | | | | | | | Receiving an interrupt whose Interrupt Status Register value has only the SRX bit set is supposed to mean that all of the data from the tag has been received. That turns out to not be true so we need to reread the FIFO Status Register to tell if there are any new bytes in the FIFO. If there are, continue receiving them; if there aren't, assume that the receive is complete and pass the data up. Signed-off-by: Mark A. Greer <mgreer@animalcreek.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* NFC: trf7970a: Handle low-watermark IRQ when transmittingMark A. Greer2014-09-071-1/+11
| | | | | | | | | | | | | | | | | | Commit 4dd836e46c3d ("NFC: trf7970a: Reset FIFO when 'End of TX' Interrupt Occurs") fixes the issue that it was meant to fix but adds the unfortunate side effect of causing the driver to report an error when the TX low-watermark level is passed during transmits. This can be fixed by checking whether the IRQ status indicates that the low-watermark has been passed when transmitting. If it has been passed and the FIFO is empty, then its safe to reset the FIFO. Otherwise, silently continue since another TX interrupt will be generated and the FIFO will be reset then. Signed-off-by: Mark A. Greer <mgreer@animalcreek.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* NFC: trf7970a: Only fill FIFO if there is spaceMark A. Greer2014-09-071-0/+6
| | | | | | | | | | | | Handle the case where trf7970a_fill_fifo() is called but there is no room in the FIFO for more TX data. When this happens, wait for another interrupt indicating that there is now space (and set a timer in case that interrupt never occurs). Signed-off-by: Mark A. Greer <mgreer@animalcreek.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* NFC: trf7970a: Prefix TX data when refilling FIFOMark A. Greer2014-09-071-15/+24
| | | | | | | | | | | | | | | | | | | | | | | | | | When refilling the FIFO with more TX data (using a new SPI transaction), the driver must prefix the TX data with a write to the FIFO I/O Register. This tells the trf7970a that the following data is destined for the FIFO so it can be transmitted. To accomplish this, the driver cannot simply push the prefix data just before the next set of TX data that is to be transmitted because that will overwrite part of the TX data provided by the digital layer. Instead, separate the prefix data and the TX data when calling trf7970a_transmit(). trf7970a_transmit() can then send the prefix and TX data from different memory locations with one spi_sync() operation. This also means that the driver doesn't require any skb "tx_headroom" as provided by the digital layer (see nfc_digital_allocate_device() and digital_skb_alloc()). Also ensure that the prefix is of type 'u8' and not 'char'. Signed-off-by: Mark A. Greer <mgreer@animalcreek.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* NFC: trf7970a: Remove unnecessary FIFO reset & RSSI readMark A. Greer2014-09-071-9/+0
| | | | | | | | | It is no longer necessary to reset the FIFO and read the 'RSSI Levels and Oscillator Status Register' so remove that code. Signed-off-by: Mark A. Greer <mgreer@animalcreek.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* NFC: trf7970a: Clear possible spurious interrupt before transmittingMark A. Greer2014-09-071-0/+6
| | | | | | | | | | The trf7970a occasionally generates spurious interrupts which can confuse the driver. To help alleviate this, clear any interrupts by reading the 'IRQ Status Register' before starting a new transaction. Signed-off-by: Mark A. Greer <mgreer@animalcreek.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* NFC: trf7970a: Recalculate driver timeout valuesMark A. Greer2014-09-071-3/+12
| | | | | | | | | | | | | | | | | | | | | | | Some of the timeout values used in the driver are not long enough to handle worst-case scenarios so they need to be recalculated. The time to wait for the FIFO to drain past the low-watermark is now 20 ms because it can take around 14.35 ms to send 95 bytes (127 bytes in full FIFO minus 32 bytes where the low-watermark interrupt will fire). 95 bytes will take around 14.35 ms at 6.62 kbps (the lowest supported bit rate used by ISO/IEC 15693) so 20 ms should be a safe value. The time to wait before issuing an EOF to complete an ISO/IEC 15693 write or lock command is 40 ms-- 20 ms to drain the FIFO and another 20 ms to ensure the wait is long enough before sending an EOF. Signed-off-by: Mark A. Greer <mgreer@animalcreek.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* NFC: trf7970a: Add RF technology specific guard timesMark A. Greer2014-09-071-1/+13
| | | | | | | | | | | | | | When turning on the RF field, the driver must wait an RF-technology-specific amount of time (known as the guard time) before modulating the field. Currently, the driver waits 5 ms but that is too short for NFCF and too long for ISO/IEC 15693. Fix this by determining the guard time when the RF technology is set and delaying that amount of time when turning on the RF field. Signed-off-by: Mark A. Greer <mgreer@animalcreek.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* NFC: trf7970a: Initialize when enabling RFMark A. Greer2014-09-071-6/+8
| | | | | | | | | | | Currently, the trf7970a is reset & initialized only when the pm_runtime resume hook is called. Instead, initialize it every time the RF is enabled to ensure that the trf7970a is quiesced and in a known state before being set up for another RF technology. Signed-off-by: Mark A. Greer <mgreer@animalcreek.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
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