Commit Graph

58 Commits

Author SHA1 Message Date
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
Mark A. Greer a08e54549e NFC: trf7970a: Initialize when enabling RF
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>
2014-09-07 23:13:43 +02:00
Mark A. Greer 6c08df422e NFC: trf7970a: Disable SYS_CLK Output
Currently, support for providing the external
SYS_CLK signal on pin 27 is not supported so
turn it off by writing to the 'Modulator and
SYS_CLK Control' register immediately after
reset.

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 17b2151733 NFC: trf7970a: Remove unnecessary sleep
There is no need to sleep for 1-2 ms before
transmitting a new command.

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 1568bfef18 NFC: trf7970a: FIFO Size is really 127 bytes
Despite what the manual says, the FIFO size
on the trf7970a is really 127 bytes so make
the code respect that.

Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-09-07 23:13:42 +02:00
Mark A. Greer 4542e8345a NFC: trf7970a: Ignore Overflow bit in FIFO Status Register
The Overflow bit in the 'FIFO Status Register' has
proven to be untrustworthy so ignore it.

Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-09-07 23:13:42 +02:00
Mark A. Greer 3e7f335689 NFC: trf7970a: Use spi_sync() instead of spi_write_then_read()
To more efficiently handle long continuous reads,
use spi_sync() instead of spi_write_then_read().

Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-09-07 23:13:42 +02:00
Mark A. Greer 24707296c7 NFC: trf7970a: Call spi_setup() to configure SPI communication
Call spi_setup() to configure SPI communication
with the trf7970a.  This will ensure that the
correct SPI parameters are used.

Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-09-07 23:13:42 +02:00
Mark A. Greer cc8d715864 NFC: trf7970a: Remove trf7970a_tg_listen_mdaa()
Currently, the digital layer 'tg_listen_mdaa'
hook is not used and it isn't necessary to have
a stub routine so remove it.

Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-09-07 23:13:42 +02:00
Mark A. Greer d3a6d33a7f NFC: trf7970a: Remove incorrect of_node_put() call
of_property_read_u32() does not take a reference
to the specified OF node so don't call of_node_put()
in trf7970a_get_autosuspend_delay().

Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-09-07 23:13:42 +02:00
Mark A. Greer f23b73526b NFC: trf7970a: Make gpio labels more readable
Make the labels for the two gpio enable lines
more user friendly by prefixing them with the
driver name.

Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-09-01 00:06:56 +02:00
Mark A. Greer 95064bd95a NFC: trf7970a: Add quirk to keep EN2 low
A bug has been discovered in the trf7970a where it
will generate an RF field even in passive target
mode when EN2 is asserted.  To work around this,
add support for the 'en2-rf-quirk' device tree
property which indicates that EN2 must remain low.

Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-09-01 00:06:55 +02:00
Mark A. Greer 772079eb77 NFC: trf7970a: Move IRQ Status Read quirk to device tree
The quirk indicating whether the trf7970a has
the "IRQ Status Read" erratum or not is currently
implemented using the 'driver_data' member of the
'spi_device_id' structure.  That requires the
driver to be modified to turn the quirk off when
a version of the trf7970a that doesn't have the
erratum is being used.  To fix that, create a
new device tree property called
'irq-status-read-quirk' that indicates that the
trf7970a being used has the erratum.

While at it, rename 'TRF7970A_QUIRK_IRQ_STATUS_READ_ERRATA'
to 'TRF7970A_QUIRK_IRQ_STATUS_READ' to make it
less of an eyesore.

Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-09-01 00:06:55 +02:00
Mark A. Greer 3bd14233aa NFC: trf7970a: Add VIN voltage override support
The trf7970a driver uses the voltage from the
power/regulator subsystem to determine what the
voltage on the VIN pin is.  Normally, this is
the right thing to do but sometimes the board
that the trf7970a is on may change the voltage.
This is the case for the trf7970atb board from
Texas Instruments where it boosts the VIN voltage
from 3.3V to 5V (see http://www.ti.com/tool/trf7970atb).

To handle this, add support for the 'vin-voltage-override'
device tree property which overrides the voltage value
given by the regulator subsystem.  When the DT property
is not present, the value from the regulator subsystem
is used.

The value of 'vin-voltage-override' is in uVolts.

Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-09-01 00:06:55 +02:00
Mark A. Greer 6857bb9627 NFC: trf7970a: Add support for Felica Type 3 tags
Add support for the Felica protocol and Type 3 tags.
Both 212 and 424 kbps are supported.

Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-05-26 01:28:28 +02:00
Mark A. Greer 742b1f9fa2 NFC: trf7970a: Add support for the ISO/IEC 14443-B and Type 4B tags
Now that the NFC digital layer has support for the ISO/IEC 14443-B
protocol and type 4B tags, add the corresponding support to the
trf7970a driver.

Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-04-22 00:37:28 +02:00
Mark A. Greer fd0c8280cf NFC: trf7970a: Add 'autosuspend-delay' DTS property
The trf7970a driver currently uses a fixed autosuspend delay of 30 seconds.
To enable users to customize the delay as they see fit, add support for the
new 'autosuspend-delay' DTS property (part of the nfc node) which can
override the default 30 seconds.

Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-04-22 00:37:28 +02:00
Mark A. Greer 18422e686e NFC: trf7970a: Don't return value from trf7970a_switch_rf_on()
trf7970a_switch_rf_on() no longer returns anything other than 0 so make
it void and clean up the code that checks for errors when its called.

Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-04-22 00:37:28 +02:00
Mark A. Greer e6403b7c75 NFC: trf7970a: Add pm_runtime support
Add pm_runtime support by moving the code that enables the trf7970a to
the pm_runtime hook routines. The pm_runtime 'autosuspend' feature is
used so that the device isn't disabled until at least 30 seconds have
passed since trf7970a_switch_rf_off() was last called.

The result is that when trf7970a_switch_rf_on() is called, the device
will be enabled and initialized (if it isn't already).  When
trf7970a_switch_rf_off() is called, it will turn off the RF immediately
but leave the device enabled for at least 30 seconds.
If 30 seconds have passed and the pm_runtime facility decides to suspend
the driver, the device will be disabled then.

Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-04-22 00:37:28 +02:00
Mark A. Greer a1d2dc5b40 NFC: trf7970a: Turn RF on after hardware is configured
The NFC digital layer calls the 'switch_rf' hook to turn the RF on before
it configures the RF technology and framing. There is potential to confuse
a tag doing it this way so don't enable the RF until the RF technology and
initial framing have been configured.

Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-04-22 00:37:27 +02:00
Mark A. Greer ebcc5a0d08 NFC: trf7970a: Set correct Vin voltage in Chip Status Control register
Currently, the trf7970a driver assumes that the Vin voltage is 5V when
it writes to the 'Chip Status Control' register. That may not be correct
so use the regulator facility to get the Vin voltage and set the VRS5_3
bit correctly when writing to that register.

Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-04-22 00:37:27 +02:00
Mark A. Greer 12e9ade309 NFC: trf7970a: Allow different Modulator and SYS_CLK Control register values
Currently the driver writes the same value to the 'Modulator and SYS_CLK
Control' register no matter what RF technology is being used. That works
for now but new RF technologies (e.g., ISO/IEC 14443-B) will require
different values to be written to that register. To support this, add a
member to the trf7970a structure which is set by the RF technology handling
code and used by the framing code when it writes to that register.

Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-04-22 00:37:27 +02:00
Mark A. Greer a0822a7e3b NFC: trf7970a: Set 'Modulator and SYS_CLK Control' after 'ISO Control'
Writing to the 'ISO Control' register may cause the contents of the
'Modulator and SYS_CLK Control' register to change so be sure to write
to 'Modulator and SYS_CLK Control' after writing to 'ISO Control'.

Note that writing to the 'Modulator and SYS_CLK Control' register
shouldn't be necessary at all according to the trf790a manual but testing
shows that it is necessary.

Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-04-22 00:37:27 +02:00