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>

Checkpatch warns about some lines over 80 characters in the Tegra I2C
driver and so fix these.

While we are at it, prefix the second instance of "STOP condition" in
the comment with a "the".
Signed-off-by: NJon Hunter <jonathanh@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

The core will do this for us now.
Signed-off-by: NWolfram Sang <wsa-dev@sang-engineering.com>
Reviewed-by: NGrygorii Strashko <grygorii.strashko@ti.com>
Acked-by: NPeter Korsgaard <peter@korsgaard.com>
Acked-by: NHeiko Stuebner <heiko@sntech.de>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
Acked-by: NThierry Reding <treding@nvidia.com>
Acked-by: NRay Jui <ray.jui@broadcom.com>
Acked-by: NVladimir Zapolskiy <vz@mleia.com>
Acked-by: NLudovic Desroches <ludovic.desroches@atmel.com>
Acked-by: NKrzysztof Kozlowski <k.kozlowski@samsung.com>
Acked-by: NLaxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Commit 497fbe24 ("i2c: tegra: enable multi master mode for tegra210")
enables the Tegra I2C 'div_clk' for adapters using the multi-master mode
during the device probe. Although the probe error path was updated to
disable the clock on probe failure, there is one place after calling
tegra_i2c_init() where the clock will not be disabled on failure. Correct
the error path so that the 'div_clk' is disabled if calling
tegra_i2c_init() fails.

Fixes: 497fbe24 ("i2c: tegra: enable multi master mode for tegra210")
Signed-off-by: NJon Hunter <jonathanh@nvidia.com>
Acked-by: NLaxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Disable clock before returning error in tegra_i2c_init() as its leaves
i2c clock ON in case of error and never turns off again as it will have
unbalanced clock enable/disable
Signed-off-by: NShardar Shariff Md <smohammed@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Enable multi-master mode in I2C_CNFG reg based on hw features.
Using single/multi-master mode bit introduced for Tegra210,
whereas multi-master mode is enabled by default in HW for T124 and
earlier Tegra SOC. Enabling this bit doesn't explicitly start
treating the bus has having multiple masters, but will start
checking for arbitration lost and reporting when it occurs.

The Tegra210 I2C controller supports single/multi master mode.
Add chipdata for Tegra210 and its compatibility string so that
Tegra210 will select data that enables multi master mode correctly.

Do below prerequisites for multi-master bus if "multi-master"
dt property entry is added.
 1. Enable 1st level clock always set.
 2. Disable 2nd level clock gating (slcg which
    is supported from T124 SOC and later chips)
Signed-off-by: NShardar Shariff Md <smohammed@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

This change will also make Coverity happy by avoiding a theoretical NULL
pointer dereference; yet another reason is to use the above helper function
to tighten the code and make it more readable.
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>
Acked-by: NLaxman Dewangan <ldewangan@nvidia.com>
Tested-by: NLaxman Dewangan <ldewangan@nvidia.com>

This code is repeated in probe:
i2c_dev->adapter.algo = &tegra_i2c_algo;

Cc: Donglin Peng <pengdonglin137@163.com>
Signed-off-by: NBarry Song <21cnbao@gmail.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Tegra I2C controller required to configure the clock divisor
register inside controller to different value based on the clock
speed. The recommended clock divisor for the I2C controller for
standard/fast mode is 0x19 and for fast-mode plus is 0x10.

Add support to configure clock divisor register of I2C controller
based on bus clock rate.

This clock divisor is supported form T114 onwards.
Signed-off-by: NChaitanya Bandi <bandik@nvidia.com>
Signed-off-by: NLaxman Dewangan <ldewangan@nvidia.com>
Tested-by: NStephen Warren <swarren@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Once the new configuration is set on the conifg register of
I2C controller, it is require to update the CONFIG_LOAD register
to transfer the new SW configuration to actual HW internal
registers that would be used in the actual logic.

It is like, SW is programming only shadow registers through
regular configuration and when these load_config bit fields
are set to 1, it causes the regular/shadows registers
configuration transferred to the HW internal active registers.
So SW has to set these bit fields at the end of all regular
registers configuration. And these config_load bits are HW
auto-clear bits. HW clears these bit fields once the register
configuration is moved to HW internal active registers. So SW
has to wait until these bits are auto-cleared before going
for any further programming

This mechanism is supported on T124 and after this SoCs.
Signed-off-by: NChaitanya Bandi <bandik@nvidia.com>
Signed-off-by: NLaxman Dewangan <ldewangan@nvidia.com>
Tested-by: NStephen Warren <swarren@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

payload_size is a 12 bit field in the HW register, so add a limit for
this size. That way we gracefully reject the message beforehand instead
of generating an OOPS while transferring. Verified using some older
Tegra2 documentation and a more recent Jetson TK1 board.
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>
Reviewed-by: NAlexander Sverdlin <alexander.sverdlin@nokia.com>

This HW cannot send 0-byte-length messages and the driver discards them.
So, we should not advertise SMBUS_QUICK.
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

return type of wait_for_completion_timeout is unsigned long not int. As ret
was only used for wait_for_completion_timeout here it is renamed to time_left
the type changed to unsigned long and references fixed up.
Signed-off-by: NNicholas Mc Guire <hofrat@osadl.org>
Reviewed-by: NAlexandre Courbot <acourbot@nvidia.com>
Acked-by: NThierry Reding <treding@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Support CPU BE mode by adding endianness conversion for memcpy interactions.
Signed-off-by: NDmitry Osipenko <digetx@gmail.com>
Acked-by: NAlexandre Courbot <acourbot@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

A platform_driver does not need to set an owner, it will be populated by the
driver core.
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Currently the i2c-tegra bus driver prepares, enables
and set_rates its clocks separately for each transfer.
This causes locking problems when doing I2C transfers
from clock notifiers; see
http://lists.infradead.org/pipermail/linux-arm-kernel/2014-July/268653.html

This patch moves clk_prepare/unprepare and clk_set_rate calls to
the probe function, leaving only clk_enable/disable to be
done on each transfer. This solves the locking issue.
Signed-off-by: NMikko Perttunen <mperttunen@nvidia.com>
Reviewed-by: NStephen Warren <swarren@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

This driver has been flagged to drop class based instantiation. The removal
improves boot-up time and is unneeded for embedded controllers. Users have been
warned to switch for some time now, so we can actually do the removal. Keep the
DEPRECATED flag, so the core can inform users that the behaviour finally
changed now. After another transition period, this flag can go, too.
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>
Reviewed-by: NMikko Perttunen <mperttunen@nvidia.com>
Tested-by: NMikko Perttunen <mperttunen@nvidia.com>
Acked-by: NThierry Reding <treding@nvidia.com>

The site-specific OOM messages are unnecessary, because they
duplicate the MM subsystem generic OOM message. For example,
k.alloc and v.alloc failures use dump_stack().
Signed-off-by: NJingoo Han <jg1.han@samsung.com>
Acked-by: NGuenter Roeck <linux@roeck-us.net>
Reviewed-by: NJean Delvare <jdelvare@suse.de>
Acked-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: NFelipe Balbi <balbi@ti.com>
Acked-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Warn users that class based instantiation is going away soon in favour
of more robust probing and faster bootup times.
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>
Acked-by: NStephen Warren <swarren@nvidia.com>

Tegra's clock driver now provides an implementation of the common
reset API (include/linux/reset.h). Use this instead of the old Tegra-
specific API; that will soon be removed.
Signed-off-by: NStephen Warren <swarren@nvidia.com>
Acked-by: NWolfram Sang <wsa@the-dreams.de>
Reviewed-by: NThierry Reding <treding@nvidia.com>

Use this new function to make code more comprehensible, since we are
reinitialzing the completion, not initializing.

[akpm@linux-foundation.org: linux-next resyncs]
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>
Acked-by: Linus Walleij <linus.walleij@linaro.org> (personally at LCE13)
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

I2C of helpers used to live in of_i2c.c but experience (from SPI) shows
that it is much cleaner to have this in the core. This also removes a
circular dependency between the helpers and the core, and so we can
finally register child nodes in the core instead of doing this manually
in each driver. So, fix the drivers and documentation, too.
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

devm_ioremap_resource does sanity checks on the given resource. No need to
duplicate this in the driver.
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>
Acked-by: NStephen Warren <swarren@nvidia.com>
Acked-by: NBarry Song <Baohua.Song@csr.com>

Tegra only supports, and always enables, device tree. Remove all ifdefs
and runtime checks for DT support from the driver. Platform data is
therefore no longer required. Delete the header that defines it.
Signed-off-by: NStephen Warren <swarren@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>