Commit Graph

80 Commits

Author SHA1 Message Date
Thomas Gleixner 8fba24537d treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 417
Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 of
  the license as published by the free software foundation

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 1 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Armijn Hemel <armijn@tjaldur.nl>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190531190113.328655274@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-05 17:37:15 +02:00
Geoff Lansberry bd751808f9 NFC: trf7970a: Correct register settings for 27MHz clock
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>
2017-06-28 09:16:54 +02:00
Mark Greer a81d1ab3ca Revert "NFC: trf7970a: Handle extra byte in response to Type 5 RMB commands"
This reverts commit ab714817d7.

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>
2017-06-23 00:20:00 +02:00
Colin Ian King e103853510 NFC: trf7970a: fix check of clock frequencies, use && instead of ||
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: 837eb4d21e ("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>
2017-06-22 23:59:01 +02:00
Mark Greer e2f0f67108 NFC: trf7970a: Clean up coding style issues
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>
2017-06-18 23:57:58 +02:00
Mark Greer d34e48d6a6 NFC: trf7970a: Convert to descriptor based GPIO interface
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>
2017-06-18 23:57:58 +02:00
Mark Greer a34631c272 NFC: trf7970a: Remove support for 'vin-voltage-override' DT property
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>
2017-06-18 23:57:58 +02:00
Mark Greer fcc652f688 NFC: trf7970a: Remove useless comment
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>
2017-06-18 23:57:58 +02:00
Mark Greer afcb9fbdba NFC: trf7970a: Only check 'en2-rf-quirk' if EN2 is specified
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>
2017-06-18 23:57:58 +02:00
Mark Greer 69f984f037 NFC: trf7970a: Fix inaccurate comment in trf7970a_probe()
As of commit ce69b95ca4 ("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>
2017-06-18 23:57:57 +02:00
Mark Greer 67dec1928d NFC: trf7970a: Don't de-assert EN2 unless it was asserted
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>
2017-06-18 23:57:57 +02:00
Geoff Lansberry 49d22c70aa NFC: trf7970a: Add device tree option of 1.8 Volt IO voltage
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>
2017-04-05 11:04:03 +02:00
Geoff Lansberry 837eb4d21e NFC: trf7970a: add device tree option for 27MHz clock
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>
2017-04-05 11:03:47 +02:00
Guan Ben ce69b95ca4 NFC: Make EN2 pin optional in the TRF7970A driver
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>
2017-04-02 00:32:34 +02:00
Geoff Lansberry 58d46f538b NFC: trf7970a: add TI recommended write of zero to Register 0x18
Signed-off-by: Geoff Lansberry <geoff@kuvee.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2016-07-04 12:20:21 +02:00
Geliang Tang 88e2ce014f NFC: trf7970a: use to_spi_device
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>
2015-12-29 19:06:12 +01:00
Linus Torvalds 75f5db39ff spi: Updates for v4.4
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.
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Merge tag 'spi-v4.4' of 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
  ...
2015-11-05 13:15:12 -08:00
Andrew F. Davis 3821a065f5 spi: Drop owner assignment from spi_drivers
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>
2015-10-28 10:30:17 +09:00
Javier Martinez Canillas 3c39c1a54a NFC: trf7970a: Add OF match table
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>
2015-10-19 19:54:04 +02:00
Mark Greer aaee24accb NFC: trf7970a: Add NULL check to clear up smatch warning
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>
2015-08-19 19:17:45 +02:00
Mark Greer ae291f79da NFC: trf7970a: SDD_EN is bit 5 not bit 3
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>
2015-08-19 19:17:45 +02:00
Mark A. Greer ab714817d7 NFC: trf7970a: Handle extra byte in response to Type 5 RMB commands
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>
2015-06-08 23:16:31 +02:00
Rafael J. Wysocki e8a9235c7c NFC / PM: Replace CONFIG_PM_RUNTIME with CONFIG_PM
After commit b2b49ccbdd (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>
2014-12-15 15:12:21 +01:00
Mark A. Greer fc0ae24386 NFC: trf7970a: Unlock mutex before exiting _trf7970a_tg_listen()
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>
2014-09-24 00:28:23 +02:00
Mark A. Greer b9e3016a53 NFC: trf7970a: Unlock mutex before exiting trf7970a_irq()
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>
2014-09-24 00:28:23 +02:00
Mark A. Greer 55ef2e75cc NFC: trf7970a: Remove unnecessary local variable initialization
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>
2014-09-24 00:28:23 +02:00
Mark A. Greer 671970f531 NFC: trf7970a: Remove useless local variable
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>
2014-09-24 00:28:22 +02:00
Mark A. Greer cb174aba86 NFC: trf7970a: Add Target Mode Detection Support
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>
2014-09-07 23:13:45 +02:00
Mark A. Greer 13b4272a82 NFC: trf7970a: Add Target Mode Support
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>
2014-09-07 23:13:45 +02:00
Mark A. Greer 1961843cee NFC: trf7970a: Handle timeout values of zero
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>
2014-09-07 23:13:45 +02:00
Mark A. Greer 6fb9edcb43 NFC: trf7970a: Cancel timer when error encountered
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>
2014-09-07 23:13:45 +02:00
Mark A. Greer 851ee3cbf8 NFC: trf7970a: Don't turn on RF if there is already an RF field
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>
2014-09-07 23:13:45 +02:00
Mark A. Greer 7149d6bfec NFC: trf7970a: trf7970a_init() turns off the RF transmitter
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>
2014-09-07 23:13:45 +02:00
Mark A. Greer cfc708dbe4 NFC: trf7970a: Don't turn off RF if its already off
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>
2014-09-07 23:13:45 +02:00
Mark A. Greer 307e5caf6f NFC: trf7970a: Add '_in_' to initiator routines
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>
2014-09-07 23:13:45 +02:00
Mark A. Greer 4e007f8106 NFC: trf7970a: Delay after initialization
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>
2014-09-07 23:13:44 +02:00
Mark A. Greer 77c9539dc1 NFC: trf7970a: Add System Suspend/Resume support
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>
2014-09-07 23:13:44 +02:00
Mark A. Greer b528281b8b NFC: trf7970a: Create startup and shutdown routines
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>
2014-09-07 23:13:44 +02:00
Mark A. Greer ceccd6aa50 NFC: trf7970a: Don't assume CONFIG_PM_RUNTIME is enabled
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>
2014-09-07 23:13:44 +02:00
Mark A. Greer b5e17d9b5b NFC: trf7970a: Rename TRF7970A_ST_OFF to TRF7970A_ST_RF_OFF
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>
2014-09-07 23:13:44 +02:00
Mark A. Greer 0a1de84205 NFC: trf7970a: Return error code when turning on RF fails
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>
2014-09-07 23:13:44 +02:00
Mark A. Greer afa5b5f13e NFC: trf7970a: Ensure no more RX data before completing receive
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>
2014-09-07 23:13:44 +02:00
Mark A. Greer 5d8f759424 NFC: trf7970a: Reread FIFO Status Register when draining FIFO
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>
2014-09-07 23:13:44 +02:00
Mark A. Greer bece3c544f NFC: trf7970a: Handle low-watermark IRQ when transmitting
Commit 4dd836e46c ("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>
2014-09-07 23:13:44 +02:00
Mark A. Greer 0e840ed59b NFC: trf7970a: Only fill FIFO if there is space
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>
2014-09-07 23:13:43 +02:00
Mark A. Greer 7a1e5552af NFC: trf7970a: Prefix TX data when refilling FIFO
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>
2014-09-07 23:13:43 +02:00
Mark A. Greer 5974150dea NFC: trf7970a: Remove unnecessary FIFO reset & RSSI read
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>
2014-09-07 23:13:43 +02:00
Mark A. Greer aff0564aa7 NFC: trf7970a: Clear possible spurious interrupt before transmitting
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>
2014-09-07 23:13:43 +02:00
Mark A. Greer 38b4eb1f7f NFC: trf7970a: Recalculate driver timeout values
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>
2014-09-07 23:13:43 +02:00
Mark A. Greer 4e64eff837 NFC: trf7970a: Add RF technology specific guard times
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>
2014-09-07 23:13:43 +02:00