Fix checkpatch.pl CHECK as follows:
CHECK: spinlock_t definition without comment
+       spinlock_t xfer_lock;
Signed-off-by: NBitan Biswas <bbiswas@nvidia.com>
Reviewed-by: NDmitry Osipenko <digetx@gmail.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Fix checkpatch.pl alignment and blank line check(s) in i2c-tegra.c
Signed-off-by: NBitan Biswas <bbiswas@nvidia.com>
Reviewed-by: NDmitry Osipenko <digetx@gmail.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Remove variable initializations in functions that
are followed by assignments before use
Signed-off-by: NBitan Biswas <bbiswas@nvidia.com>
Reviewed-by: NDmitry Osipenko <digetx@gmail.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Clean up macros by:
1) removing unused macros
2) replace constants by macro BIT()
Signed-off-by: NBitan Biswas <bbiswas@nvidia.com>
Reviewed-by: NDmitry Osipenko <digetx@gmail.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Commit 86c92b99 ("i2c: tegra: Add DMA support") added DMA support
to the Tegra I2C driver for Tegra devices that support the APB DMA
controller. One side-effect of this change is that even for Tegra
devices that do not have an APB DMA controller and hence, cannot
support DMA tranfers for I2C transactions, the following error messages
are still displayed ...

 ERR KERN tegra-i2c 31c0000.i2c: cannot use DMA: -19
 ERR KERN tegra-i2c 31c0000.i2c: falling back to PIO

There is no point displaying the above messages for devices that do not
have an APB DMA controller and so fix this by returning from the
tegra_i2c_init_dma() function if 'has_apb_dma' is not true.

Furthermore, if CONFIG_TEGRA20_APB_DMA is not set, then rather than
printing an error message, print an debug message as for whatever reason
this could be intentional.

Fixes: 86c92b99 ("i2c: tegra: Add DMA support")
Signed-off-by: NJonathan Hunter <jonathanh@nvidia.com>
Reviewed-by: NDmitry Osipenko <digetx@gmail.com>
Acked-by: NThierry Reding <treding@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Multi-master support is defeatured on Tegra210 and Tegra186 due to
known bugs.

This patch removes multi-master support for Tegra210 and Tegra186
I2C HW feature.
Acked-by: NThierry Reding <treding@nvidia.com>
Signed-off-by: NSowjanya Komatineni <skomatineni@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Tegra186 does not have master FIFO  control register and instead
uses FIFO control register like prior Tegra chipset.

This patch fixes this and prevents crashing during boot when
accessing FIFO control registers.
Acked-by: NThierry Reding <treding@nvidia.com>
Signed-off-by: NSowjanya Komatineni <skomatineni@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

The phrasing in two dev_err messages is using fallbacking which
os less understandable than "falling back", so fix this up.
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Acked-by: NThierry Reding <treding@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

This patch adds I2C interface timing registers support for
proper bus rate configuration along with meeting the I2C spec
setup and hold times based on the tuning performed on Tegra210,
Tegra186 and Tegra194 platforms.

I2C_INTERFACE_TIMING_0 register contains TLOW and THIGH field
and Tegra I2C controller design uses them as a part of internal
clock divisor.

I2C_INTERFACE_TIMING_1 register contains the setup and hold times
for start and stop conditions.
Acked-by: NThierry Reding <treding@nvidia.com>
Reviewed-by: NDmitry Osipenko <digetx@gmail.com>
Tested-by: NDmitry Osipenko <digetx@gmail.com>
Signed-off-by: NSowjanya Komatineni <skomatineni@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Tegra194 allows max of 64K bytes and Tegra186 and prior allows
max of 4K bytes of transfer per packet.

one sec timeout is not enough for transfers more than 10K bytes
at STD bus rate.

This patch updates I2C transfer timeout based on the transfer size
and I2C bus rate to allow enough time during max transfer size at
lower bus speed.
Acked-by: NThierry Reding <treding@nvidia.com>
Reviewed-by: NDmitry Osipenko <digetx@gmail.com>
Signed-off-by: NSowjanya Komatineni <skomatineni@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

This patch adds DMA support for Tegra I2C.

Tegra I2C TX and RX FIFO depth is 8 words. PIO mode is used for
transfer size of the max FIFO depth and DMA mode is used for
transfer size higher than max FIFO depth to save CPU overhead.

PIO mode needs full intervention of CPU to fill or empty FIFO's
and also need to service multiple data requests interrupt for the
same transaction. This adds delay between data bytes of the same
transfer when CPU is fully loaded and some slave devices has
internal timeout for no bus activity and stops transaction to
avoid bus hang. DMA mode is helpful in such cases.

DMA mode is also helpful for Large transfers during downloading or
uploading FW over I2C to some external devices.

Tegra210 and prior Tegra chips use APBDMA driver which is replaced
with GPCDMA on Tegra186 and Tegra194.
This patch uses has_apb_dma flag in hw_feature to differentiate
DMA driver change between Tegra chipset.

APBDMA driver is registered from module-init level and this patch
also has a change to register I2C driver at module-init level
rather than subsys-init to avoid deferring I2C probe till APBDMA
driver is registered.
Acked-by: NThierry Reding <treding@nvidia.com>
Reviewed-by: NDmitry Osipenko <digetx@gmail.com>
Tested-by: NDmitry Osipenko <digetx@gmail.com>
Signed-off-by: NSowjanya Komatineni <skomatineni@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Tegra194 supports maximum 64K bytes per packet including 12 bytes of
packet header irrespective of PIO or DMA mode transfer.

This patch updates Tegra194 max write length to account for packet
header size for transfers.

Cc: stable@vger.kernel.org # 4.20+
Reviewed-by: NDmitry Osipenko <digetx@gmail.com>
Signed-off-by: NSowjanya Komatineni <skomatineni@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Tegra186 and prior supports maximum 4K bytes per packet transfer
including 12 bytes of packet header.

This patch fixes max write length limit to account packet header
size for transfers.

Cc: stable@vger.kernel.org # 4.4+
Reviewed-by: NDmitry Osipenko <digetx@gmail.com>
Signed-off-by: NSowjanya Komatineni <skomatineni@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Bus clear feature of Tegra I2C controller helps to recover from
bus hang when I2C master loses the bus arbitration due to the
slave device holding SDA LOW continuously for some unknown reasons.

Per I2C specification, the device that held the bus LOW should
release it within 9 clock pulses.

During bus clear operation, Tegra I2C controller sends 9 clock
pulses and terminates the transaction with STOP condition.
Upon successful bus clear operation, bus goes to idle state and
driver retries the transaction.
Acked-by: NThierry Reding <treding@nvidia.com>
Reviewed-by: NDmitry Osipenko <digetx@gmail.com>
Signed-off-by: NSowjanya Komatineni <skomatineni@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

This patch sorts all the include headers alphabetically for the
I2C Tegra driver.
Acked-by: NThierry Reding <treding@nvidia.com>
Reviewed-by: NDmitry Osipenko <digetx@gmail.com>
Signed-off-by: NSowjanya Komatineni <skomatineni@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Tegra194 supports maximum 64K Bytes transfer per packet.
Tegra186 and prior supports maximum 4K Bytes transfer per packet.

This patch fixes this payload difference between Tegra194 and prior
Tegra chipsets using separate i2c_adapter_quirks.
Signed-off-by: NSowjanya Komatineni <skomatineni@nvidia.com>
Acked-by: NThierry Reding <treding@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Adopt the SPDX license identifier headers to ease license compliance
management.
Signed-off-by: NThierry Reding <treding@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Not all fields were properly documented. Add kerneldoc for the missing
fields to prevent the build from flagging them.
Reported-by: NWolfram Sang <wsa@the-dreams.de>
Signed-off-by: NThierry Reding <treding@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Some of the kerneldoc uses a strange spelling for abbreviations. Turn
them into all-uppercase and clean up some whitespace issues while at it.
Signed-off-by: NThierry Reding <treding@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

As you are already in ISR, it is unnecessary to call spin_lock_irqsave.
Signed-off-by: Njun qian <hangdianqj@163.com>
Reviewed-by: NDmitry Osipenko <digetx@gmail.com>
Acked-by: NThierry Reding <treding@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

And don't reimplement in the driver.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: NJon Hunter <jonathanh@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

On Tegra30 Cardhu the PCA9546 I2C mux is not ACK'ing I2C commands on
resume from suspend (which is caused by the reset signal for the I2C
mux not being configured correctl). However, this NACK is causing the
Tegra30 to hang on resuming from suspend which is not expected as we
detect NACKs and handle them. The hang observed appears to occur when
resetting the I2C controller to recover from the NACK.

Commit 77821b46 ("i2c: tegra: proper handling of error cases") added
additional error handling for some error cases including NACK, however,
it appears that this change conflicts with an early fix by commit
f70893d0 ("i2c: tegra: Add delay before resetting the controller
after NACK"). After commit 77821b46 was made we now disable 'packet
mode' before the delay from commit f70893d0 happens. Testing shows
that moving the delay to before disabling 'packet mode' fixes the hang
observed on Tegra30. The delay was added to give the I2C controller
chance to send a stop condition and so it makes sense to move this to
before we disable packet mode. Please note that packet mode is always
enabled for Tegra.

Fixes: 77821b46 ("i2c: tegra: proper handling of error cases")
Signed-off-by: NJon Hunter <jonathanh@nvidia.com>
Acked-by: NThierry Reding <treding@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>
Cc: stable@vger.kernel.org

In order to support advanced features, the I2C FIFO interface was
changed in the version of the Tegra I2C controller found in Tegra194.
The changes are backwards incompatible, so the driver needs to be
programmed in a slightly different way on new chips.

Add support for MST FIFO programming and add an OF match entry for
Tegra194. At the same time, mark all prior generations of this
controller as not having the MST FIFO interface.
Acked-by: NJon Hunter <jonathanh@nvidia.com>
Signed-off-by: NThierry Reding <treding@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Nothing prevents I2C clients to access I2C while Tegra's driver is being
suspended, this results in -EBUSY error returned to the clients and that
may have unfortunate consequences. In particular this causes problems
for the TPS6586x MFD driver which emits hundreds of "failed to read
interrupt status" error messages on resume from suspend. This happens if
TPS6586X is used to wake system from suspend by the expired RTC alarm
timer because TPS6586X is an I2C device driver and its IRQ handler reads
the status register while Tegra's I2C driver is suspended, i.e. just after
kernel enabled IRQ's during of resume-from-suspend process.

Note that the removed tegra_i2c_resume() invoked tegra_i2c_init() which
performs HW reset. That seems was also not entirely correct because moving
tegra_i2c_resume to an earlier stage of resume-from-suspend process causes
I2C transfer to fail in the case of TPS6586X. It is fine to remove the
HW-reinitialization for now because it should be only needed in a case of
using lowest power-mode during suspend, which upstream kernel doesn't
support.
Signed-off-by: NDmitry Osipenko <digetx@gmail.com>
Acked-by: NLaxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Make these const as they are only stored as a reference in the quirks
field of an i2c_adapter structure, which is const. Done using
Coccinelle.
Signed-off-by: NBhumika Goyal <bhumirks@gmail.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Commit a53e35db ("reset: Ensure drivers are explicit when requesting
reset lines") started to transition the reset control request API calls
to explicitly state whether the driver needs exclusive or shared reset
control behavior. Convert all drivers requesting exclusive resets to the
explicit API call so the temporary transition helpers can be removed.

No functional changes.

Cc: Laxman Dewangan <ldewangan@nvidia.com>
Cc: Wolfram Sang <wsa@the-dreams.de>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Jonathan Hunter <jonathanh@nvidia.com>
Cc: linux-i2c@vger.kernel.org
Cc: linux-tegra@vger.kernel.org
Signed-off-by: NPhilipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Fix the following warnings reported by coccinelle for the Tegra I2C
driver.

drivers/i2c/busses/i2c-tegra.c:513:2-23: WARNING: Assignment of bool to 0/1
drivers/i2c/busses/i2c-tegra.c:539:3-24: WARNING: Assignment of bool to 0/1
Reported-by: NWolfram Sang <wsa@the-dreams.de>
Signed-off-by: NJon Hunter <jonathanh@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

To summarize the issue observed in error cases:

SW Flow: For i2c message transfer, packet header and data payload is
posted and then required error/packet completion interrupts are enabled
later.

HW flow: HW process the packet just after packet header is posted, if
ARB lost/NACK error occurs (SW will not handle immediately when error
happens as error interrupts are not enabled at this point). HW assumes
error is acknowledged and clears current data in FIFO, But SW here posts
the remaining data payload which still stays in FIFO as stale data
(data without packet header).

Now once the interrupts are enabled, SW handles ARB lost/NACK error by
clearing the ARB lost/NACK interrupt. Now HW assumes that SW attended
the error and will parse/process stale data (data without packet header)
present in FIFO which causes invalid NACK errors.

Fix: Enable the error interrupts before posting the packet into FIFO
which make sure HW to not clear the fifo. Also disable the packet mode
before acknowledging errors (ARB lost/NACK error) to not process any
stale data. As error interrupts are enabled before posting the packet
header use spinlock to avoid preempting.
Signed-off-by: NShardar Shariff Md <smohammed@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Use readl_poll_timeout_atomic() function as *wait_for_config_load()
function can be called from interrupt context.
Signed-off-by: NShardar Shariff Md <smohammed@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Define separate function for configuration load register handling
to make it use by different functions later.
Signed-off-by: NShardar Shariff Md <smohammed@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

During i2c controller initialization, when fifo flush fails return error
instead of returning the error during exit.
Signed-off-by: NShardar Shariff Md <smohammed@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

After CONFIG_LOAD register is programmed instead of explicitly waiting
for timeout, use readl_poll_timeout() to check for register value to get
updated or wait till timeout.
Signed-off-by: NShardar Shariff Md <smohammed@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

On Tegra124/132 the pins for I2C6 are shared with the Display Port AUX
(DPAUX) channel and on Tegra210 the pins for I2C4 and I2C6 are shared
with DPAUX1 and DPAUX0, respectively. The multiplexing of the pins is
handled by a register in the DPAUX and so the Tegra DPAUX driver has
been updated to register a pinctrl device for managing these pins.

The pins for these particular I2C devices are bound to the I2C device
prior to probing. However, these I2C devices are in a different power
partition to the DPAUX devices that own the pins. Hence, it is desirable
to place the pins in the 'idle' state and allow the DPAUX power
partition to switch off, when these I2C devices is not in use.
Therefore, add calls to place the I2C pins in the 'default' and 'idle'
states when the I2C device is runtime resumed and suspended,
respectively.

Please note that the pinctrl functions that set the state of the pins
check to see if the devices has pins associated and will return zero
if they do not. Therefore, it is safe to call these pinctrl functions
even for I2C devices that do not have any pins associated.
Signed-off-by: NJon Hunter <jonathanh@nvidia.com>
Acked-by: NLaxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Update the Tegra I2C driver to use runtime PM and move the code in the
tegra_i2c_clock_enable/disable() functions to the PM runtime resume and
suspend callbacks, respectively.

Note that given that CONFIG_PM is not mandatory for Tegra, if CONFIG_PM
is not enabled and so runtime PM is not enabled, ensure that the I2C
clocks are turned on during probe and kept on by calling the resume
callback directly.

In the function tegra_i2c_init(), the variable 'err' does not need to be
initialised to zero in tegra_i2c_init() because it is initialised when
pm_runtime_get_sync() is called. Furthermore, to ensure we only return 0
from tegra_i2c_init(), it is necessary to re-initialise 'err' to 0 after
a successful call to pm_runtime_get_sync() because it can return a
positive value on success. However, alternatively re-initialise 'err' by
using the return value of the function tegra_i2c_flush_fifos() because
it can only be 0 or -ETIMEDOUT.
Signed-off-by: NJon Hunter <jonathanh@nvidia.com>
Acked-by: NLaxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

The I2C adapter is unlocked regardless of whether the tegra_i2c_init()
called during the resume is successful or not. However, if the
tegra_i2c_init() is not successful, then ->is_suspended is not set to
false. Simplify the resume code by only setting ->is_suspended to false
if tegra_i2c_init() is successful and return the error code from
tegra_i2c_init().
Signed-off-by: NJon Hunter <jonathanh@nvidia.com>
Acked-by: NLaxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

All Tegra I2C devices have the name "Tegra I2C adapter" which is not
very useful when viewing the I2C adapter names via the sysfs. Therefore,
use the device name, which is unique for each I2C device, instead.
Signed-off-by: NJon Hunter <jonathanh@nvidia.com>
Acked-by: NLaxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Tegra has only supported device-tree for platform/board configuration
for quite some time now and so simplify the Tegra I2C driver by dropping
code for non device-tree platforms/boards.
Signed-off-by: NJon Hunter <jonathanh@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Add missing new line characters for the various error messages.
Signed-off-by: NJon Hunter <jonathanh@nvidia.com>
Acked-by: NLaxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Checkpatch warns about missing blank lines after declarations in the
Tegra I2C driver and so fix these.

Note that the initialisation of 'val' to zero in tegra_dvc_init() is
unnecessary and so remove this.
Signed-off-by: NJon Hunter <jonathanh@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Checkpatch warns about spacing around the '<<' operator in the Tegra I2C
driver and so fix these by converting the bit definitions that are using
this operator to use the BIT macro.
Signed-off-by: NJon Hunter <jonathanh@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>