I2C: Explicitly include correct DT includes

The DT of_device.h and of_platform.h date back to the separate
of_platform_bus_type before it as merged into the regular platform bus.
As part of that merge prepping Arm DT support 13 years ago, they
"temporarily" include each other. They also include platform_device.h
and of.h. As a result, there's a pretty much random mix of those include
files used throughout the tree. In order to detangle these headers and
replace the implicit includes with struct declarations, users need to
explicitly include the correct includes.

Signed-off-by: Rob Herring <robh@kernel.org>
Reviewed-by: Andi Shyti <andi.shyti@kernel.org>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

i2c: Convert to platform remove callback returning void

The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is (mostly) ignored
and this typically results in resource leaks. To improve here there is a
quest to make the remove callback return void. In the first step of this
quest all drivers are converted to .remove_new() which already returns
void.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Alain Volmat <alain.volmat@foss.st.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Baruch Siach <baruch@tkos.co.il>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Acked-by: Jochen Friedrich <jochen@scram.de>
Acked-by: Peter Rosin <peda@axentia.se>
Acked-by: Vadim Pasternak <vadimp@nvidia.com>
Reviewed-by: Asmaa Mnebhi <asnaa@nvidia.com>
Reviewed-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Reviewed-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Reviewed-by: Chris Pringle <chris.pringle@phabrix.com>
Reviewed-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>
Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>
Reviewed-by: Tali Perry <tali.perry@nuvoton.com>
Reviewed-by: Vignesh Raghavendra <vigneshr@ti.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

i2c: mxs: ensure that DMA buffers are safe for DMA

We found that after commit 9c46929e7989
("ARM: implement THREAD_INFO_IN_TASK for uniprocessor systems"), the
PCF85063 RTC driver stopped working on i.MX28 due to regmap_bulk_read()
reading bogus data into a stack buffer. This is caused by the i2c-mxs
driver using DMA transfers even for messages without the I2C_M_DMA_SAFE
flag, and the aforementioned commit enabling vmapped stacks.

As the MXS I2C controller requires DMA for reads of >4 bytes, DMA can't be
disabled, so the issue is fixed by using i2c_get_dma_safe_msg_buf() to
create a bounce buffer when needed.

Fixes: 9c46929e7989 ("ARM: implement THREAD_INFO_IN_TASK for uniprocessor systems")
Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

i2c: mxs: suppress probe-deferral error message

During boot of I2SE Duckbill the kernel log contains a
confusing error:

Failed to request dma

This is caused by i2c-mxs tries to request a not yet available DMA
channel (-EPROBE_DEFER). So suppress this message by using
dev_err_probe().

Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

i2c: move drivers from strlcpy to strscpy

Follow the advice of the below link and prefer 'strscpy'. Conversion is
easy because no driver used the return value and has been done with a
simple sed invocation.

Link: https://lore.kernel.org/r/CAHk-=wgfRnXz0W3D37d01q3JFkr_i_uTL=V6A6G1oUZcprmknw@mail.gmail.com/
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

i2c: mxs: Silence a clang warning

Change the of_device_get_match_data() cast to (uintptr_t)
to silence the following clang warning:

drivers/i2c/busses/i2c-mxs.c:802:18: warning: cast to smaller integer type 'enum mxs_i2c_devtype' from 'const void *' [-Wvoid-pointer-to-enum-cast]

Reported-by: kernel test robot <lkp@intel.com>
Fixes: c32abd8b5691 ("i2c: mxs: Remove unneeded platform_device_id")
Signed-off-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

i2c: mxs: : use proper DMAENGINE API for termination

dmaengine_terminate_all() is deprecated in favor of explicitly saying if
it should be sync or async. Here, we want dmaengine_terminate_sync()
because there is no other synchronization code in the driver to handle
an async case.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

i2c: mxs: Remove unneeded platform_device_id

The i2c-mxs driver only runs on DT-platform and there is no
need to use the platform_device_id structure to pass the driver
data.

Get rid of it to make the code simpler.

Signed-off-by: Fabio Estevam <festevam@gmail.com>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

i2c: mxs: use MXS_DMA_CTRL_WAIT4END instead of DMA_CTRL_ACK

The driver-specific usage of the DMA_CTRL_ACK flag was replaced with a
custom flag in commit ceeeb99cd821 ("dmaengine: mxs: rename custom flag"),
but i2c-mxs was not updated to use the new flag, completely breaking I2C
transactions using DMA.

Fixes: ceeeb99cd821 ("dmaengine: mxs: rename custom flag")
Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

i2c: drivers: Use generic definitions for bus frequencies

Since we have generic definitions for bus frequencies, let's use them.

Reviewed-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Acked-by: Robert Richter <rrichter@marvell.com>
Reviewed-by: Thor Thayer <thor.thayer@linux.intel.com>
Acked-by: Elie Morisse <syniurge@gmail.com>
Acked-by: Nehal Shah <nehal-bakulchandra.shah@amd.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Acked-by: Scott Branden <scott.branden@broadcom.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Acked-by: Baruch Siach <baruch@tkos.co.il>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Oleksij Rempel <o.rempel@pengutronix.de>
Acked-by: Vladimir Zapolskiy <vz@mleia.com>
Acked-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: Chris Brandt <chris.brandt@renesas.com>
Reviewed-by: Baolin Wang <baolin.wang7@gmail.com>
Reviewed-by: Pierre-Yves MORDRET <pierre-yves.mordret@st.com>
Acked-by: Patrice Chotard <patrice.chotard@st.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
Acked-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

i2c: mxs: Use dma_request_chan() instead dma_request_slave_channel()

dma_request_slave_channel() is a wrapper on top of dma_request_chan()
eating up the error code.

By using dma_request_chan() directly the driver can support deferred
probing against DMA.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

i2c: mxs: use devm_platform_ioremap_resource() to simplify code

Use the new helper devm_platform_ioremap_resource() which wraps the
platform_get_resource() and devm_ioremap_resource() together, to
simplify the code.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Reviewed-by: Dong Aisheng <aisheng.dong@nxp.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

i2c: mxs: use core to detect 'no zero length' quirk

And don't reimplement in the driver.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

i2c: mxs: Switch to SPDX identifier

Adopt the SPDX license identifier headers to ease license compliance
management.

Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

i2c: busses: make use of i2c_8bit_addr_from_msg

Because it looks neater.

For diolan, this allows factoring out some code that is now common
between if and else.

For eg20t, pch_i2c_writebytes is always called with a write in
msgs->flags, and pch_i2c_readbytes with a read.

For imx, i2c_imx_dma_write and i2c_imx_write are always called with a
write in msgs->flags, and i2c_imx_read with a read.

For qup, qup_i2c_write_tx_fifo_v1 is always called with a write in
qup->msg->flags.

For stu300, also restructure debug output for resends, since that
code as a result is only handling debug output.

Reviewed-by: Guenter Roeck <linux@roeck-us.net> [diolan]
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> [efm32 and imx]
Acked-by: Linus Walleij <linus.walleij@linaro.org> [stu300]
Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

i2c: mxs: use true and false for boolean values

Assign true or false to boolean variables instead of an integer value.

This issue was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

i2c: mxs: change error printing to debug for mxs_i2c_pio_wait_xfer_end

Instead of printing errors after mxs_i2c_pio_wait_xfer_end returns with
an error code just print a debug message.

NAKs and timeouts can occur in this situation normally, so do not treat
them as errors.

Signed-off-by: Michael Thalmeier <michael.thalmeier@hale.at>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

i2c: don't print error when adding adapter fails

The core will do this for us now.

Signed-off-by: Wolfram Sang <wsa-dev@sang-engineering.com>
Reviewed-by: Grygorii Strashko <grygorii.strashko@ti.com>
Acked-by: Peter Korsgaard <peter@korsgaard.com>
Acked-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Acked-by: Ray Jui <ray.jui@broadcom.com>
Acked-by: Vladimir Zapolskiy <vz@mleia.com>
Acked-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Acked-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Acked-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

i2c: constify platform_device_id

The platform_device_id is not modified by these drivers and core uses it
as const.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski.k@gmail.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

i2c: mxs: fix broken email address

My Pengutronix address is not valid anymore, redirect people to the Pengutronix
kernel team.

Reported-by: Harald Geyer <harald@ccbib.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Acked-by: Robert Schwebel <r.schwebel@pengutronix.de>

i2c: mxs: match wait_for_completion_timeout return type

Return type of wait_for_completion_timeout is unsigned long not int.
An appropriately named unsigned long is added and the assignment fixed up.

Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

i2c: imx+mxs: Use the preferred form for passing a size of a struct

According to Documentation/CodingStyle - Chapter 14:

"The preferred form for passing a size of a struct is the following:

p = kmalloc(sizeof(*p), ...);

The alternative form where struct name is spelled out hurts readability and
introduces an opportunity for a bug when the pointer variable type is changed
but the corresponding sizeof that is passed to a memory allocator is not."

So do it as recommeded.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

i2c: busses: drop owner assignment from platform_drivers

A platform_driver does not need to set an owner, it will be populated by the
driver core.

Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

i2c: mxs: detect No Slave Ack on SELECT in PIO mode

i2cdetect scanned i2c bus slow because the i2c-mxs driver ignored the
NO_SLAVE_ACK bit during busy-waiting loop. Thanks to the patch, the
speedup happens.

Signed-off-by: Janusz Uzycki <j.uzycki@elproma.com.pl>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

i2c: mxs: fix error message in pio transfer

If I2C_M_RD flag is set SELECT command is sent and afterward READ
command. The patch fixes READ command to return READ failure error
message instead of SELECT failure error message.

Signed-off-by: Janusz Uzycki <j.uzycki@elproma.com.pl>
Acked-by: Marek Vasut <marex@denx.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

i2c: mxs: Use devm_ioremap_resource()

Use devm_ioremap_resource() in order to make the code simpler,
and remove redundant return value check of platform_get_resource()
because the value is checked by devm_ioremap_resource().

Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Acked-by: Shawn Guo <shawn.guo@linaro.org>
Acked-by: Marek Vasut <marex@denx.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

tree-wide: use reinit_completion instead of INIT_COMPLETION

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: Wolfram 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

i2c: i2c-mxs: replace platform_driver_probe to support deferred probing

Subsystems like pinctrl and gpio rightfully make use of deferred probing at
core level. Now, deferred drivers won't be retried if they don't have a .probe
function specified in the driver struct. Fix this driver to have that, so the
devices it supports won't get lost in a deferred probe.

Acked-by: Marek Vasut <marex@denx.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

i2c: mxs: Fix PIO mode on i.MX23

The i.MX23 I2C controller is also capable of PIO, but needs a little harder
push to behave. The controller needs to be reset after every PIO/DMA operation
for some reason, otherwise in rare cases, the controller can hang or emit
bytes onto the bus.

Signed-off-by: Marek Vasut <marex@denx.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

i2c: mxs: Rework the PIO mode operation

Analyze and rework the PIO mode operation. The PIO mode operation
was unreliable on MX28, by analyzing the bus with LA, the checks
for when data were available or were to be sent were wrong.

The PIO WRITE has to be completely reworked as it multiple problems.
The MX23 datasheet helped here, see comments in the code for details.
The problems boil down to:
- RUN bit in CTRL0 must be set after DATA register was written
- The PIO transfer must be 4 bytes long tops, otherwise use
clock stretching.
Both of these fixes are implemented.

The PIO READ operation can only be done for up to four bytes as
we are unable to read out the data from the DATA register fast
enough.

This patch also tries to document the investigation within the
code.

Signed-off-by: Marek Vasut <marex@denx.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

i2c: mxs: distinguish i.MX23 and i.MX28 based I2C controller

It seems the PIO mode does not work, or at least not like it works
on a i.MX28. Each short transfer needs about one second (without an
error message) but does not send anything on the I2C lines.

Signed-off-by: Juergen Beisert <jbe@pengutronix.de>
Signed-off-by: Marek Vasut <marex@denx.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

i2c: move OF helpers into the core

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: Wolfram Sang <wsa@the-dreams.de>

i2c: mxs: fix broken timing calculation

The timing calculation is rather bogus and gives extremely wrong
results for higher frequencies (on an i.MX28). E.g. instead of 400 kHz
I measured 770 kHz.

Implement a calculation that adheres to the I2C spec and gives exact
results for I2C frequencies from 12.56 kHz to 960 kHz.

Also the bus_free and leadin parameters are programmed according to
the I2C spec for standard and fast mode.

This was tested on a Ka-Ro TX28 module with a DS1339, TSC2007, PCA9554
and SGTL5000 client.

Signed-off-by: Lothar Waßmann <LW@KARO-electronics.de>
Acked-by: Marek Vasut <marex@denx.de>
[wsa: patch fixes whitespace issue, too]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

i2c: mxs: Check the return value from stmp_reset_block()

stmp_reset_block() may fail, so let's check its return value and propagate it in
the case of error.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Acked-by: Marek Vasut <marex@denx.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

i2c: i2c-mxs: Use DMA mode even for small transfers

Recently we have been seing some reports about PIO mode not working properly.

- http://www.spinics.net/lists/linux-i2c/msg11985.html
- http://marc.info/?l=linux-i2c&m=137235593101385&w=2
- https://lkml.org/lkml/2013/6/24/430

Let's use DMA mode even for small transfers.

Without this patch, i2c reads the incorrect sgtl5000 version on a mx28evk when
touchscreen is enabled:

[ 5.856270] sgtl5000 0-000a: Device with ID register 0 is not a sgtl5000
[ 9.877307] sgtl5000 0-000a: ASoC: failed to probe CODEC -19
[ 9.883528] mxs-sgtl5000 sound.12: ASoC: failed to instantiate card -19
[ 9.892955] mxs-sgtl5000 sound.12: snd_soc_register_card failed (-19)

Cc: <stable@vger.kernel.org>
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Acked-by: Shawn Guo <shawn.guo@linaro.org>
Acked-by: Lucas Stach <l.stach@pengutronix.de>
Acked-by: Marek Vasut <marex@denx.de>

[wsa: we have a proper solution for -next, so this non intrusive
solution is OK for now]

Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

i2c: mxs: Let device core handle pinctrl

Since commit ab78029 (drivers/pinctrl: grab default handles from device core),
we can rely on device core for handling pinctrl.

So remove devm_pinctrl_get_select_default() from the driver.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

i2c: mxs: do error checking and handling in PIO mode

In PIO mode we can end up with the same errors as in DMA mode, but as IRQs
are disabled there we have to check for them manually after each command.

Also don't use the big controller reset hammer when receiving a NAK from a
slave. It's sufficient to tell the controller to continue at a clean state.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Tested-by: Marek Vasut <marex@denx.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

i2c: mxs: remove races in PIO code

This commit fixes the three following races in PIO code:

- The CTRL0 register is racy in itself, when programming transfer state and
run bit in the same cycle the hardware sometimes ends up using the state
from the last transfer. Fix this by programming state in one cycle, make
sure the write is flushed down APBX bus by reading back the reg and only
then trigger the run bit.

- Only clear the DMAREQ bit in DEBUG0 after the read/write to the data reg
happened. Otherwise we are racing with the hardware about who touches
the data reg first.

- When checking for completion of a transfer it's not sufficient to check
if the data engine finished, but also a check for i2c bus idle is needed.
In PIO mode we are really fast to program the next transfer after a finished
one, so the controller possibly tries to start a new transfer while the
clkgen engine is still busy writing the NAK/STOP from the last transfer to
the bus.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

i2c: i2c-mxs: move to use generic DMA helper

With the generic DMA device tree helper supported by mxs-dma driver,
client devices only need to call dma_request_slave_channel() for
requesting a DMA channel from dmaengine.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Wolfram Sang <wsa@the-dreams.de>

i2c: Ignore return value of i2c_del_adapter()

i2c_del_adapter() always returns 0. So all checks testing whether it will be
non zero will always evaluate to false and the conditional code is dead code.
This patch updates all callers of i2c_del_mux_adapter() to ignore the return
value and assume that it will always succeed (which it will). In a subsequent
patch the return type of i2c_del_adapter() will be made void.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Ben Hutchings <bhutchings@solarflare.com>
Reviewed-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

i2c: Remove unneeded xxx_set_drvdata(..., NULL) calls

There is simply no reason to be manually setting the private driver
data to NULL in the remove/fail to probe cases. This is just extra
cruft code that can be removed.

A few notes:
* Nothing relies on drvdata being set to NULL.
* The __device_release_driver() function eventually calls
dev_set_drvdata(dev, NULL) anyway, so there's no need to do it
twice.
* I verified that there were no cases where xxx_get_drvdata() was
being called in these drivers and checking for / relying on the NULL
return value.

This could be cleaned up kernel-wide but for now just take the baby
step and remove from the i2c subsystem.

Reported-by: Wolfram Sang <wsa@the-dreams.de>
Reported-by: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Doug Anderson <dianders@chromium.org>
Reviewed-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Peter Korsgaard <jacmet@sunsite.dk>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Marek Vasut <marex@denx.de>
Signed-off-by: Wolfram Sang <wolfram@the-dreams.de>

i2c: mxs: Implement arbitrary clock speed derivation algorithm

This patch drops the i2c timing tables from this driver and instead
derives the timing based from the requested clock sleep. The timing
tables were completely wrong anyway when observed on a scope.

This new algorithm is also only derived by using a scope, but it seems
to produce much more accurate result.

Signed-off-by: Marek Vasut <marex@denx.de>
Tested-by: Shawn Guo <shawn.guo@linaro.org>
[wsa: changed messages from dev_err to dev_warn]
Signed-off-by: Wolfram Sang <wolfram@the-dreams.de>

i2c: mxs: Add PIO and mixed-DMA support

Add support for the PIO mode and mixed PIO/DMA mode support. The mixed
PIO/DMA is the default mode of operation. This shall leverage overhead
that the driver creates due to setting up DMA descriptors even for very
short transfers.

The current boundary between PIO/DMA 8 bytes, transfers shorter than 8
bytes are transfered by PIO, longer transfers use DMA. The performance
of write transfers remains unchanged, while there is a minor improvement
of read performance. Reading 16KB EEPROM with DMA-only operations gives
a read speed of 39.5KB/s, while with then new mixed-mode the speed is
blazing 40.6KB/s.

Signed-off-by: Marek Vasut <marex@denx.de>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

i2c: mxs: Fix type of error code

cmd_err is used to handle error code, so it should not be unsigned.

This fixes the following warning when building with W=1 option:

drivers/i2c/busses/i2c-mxs.c: In function 'mxs_i2c_xfer_msg':
drivers/i2c/busses/i2c-mxs.c:331:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Acked-by: Marek Vasut <marex@denx.de>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Cc: stable@kernel.org

i2c: mxs: Fix misuse init_completion

The init_completion() call does reinit not only the variable carrying
the flag that the completion finished, but also initialized the
waitqueue associated with the completion. On the contrary, the
INIT_COMPLETION() call only reinits the flag.

In case there was anything still stuck in the waitqueue, subsequent call
to init_completion() would be able to create possible race condition. This
patch uses the proper function and moves init_completion() into .probe() call
of the driver, to be issued only once.

Note that such scenario is impossible, since two threads can never enter the
mxs_i2c_xfer_msg(), since whole this section is protected by mutex in I2C core.
This by no means allows this issue to exit though.

Signed-off-by: Marek Vasut <marex@denx.de>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

i2c: remove __dev* attributes from subsystem

CONFIG_HOTPLUG is going away as an option. As result the __dev*
markings will be going away.

Remove use of __devinit, __devexit_p, __devinitdata, __devinitconst,
and __devexit.

Signed-off-by: Bill Pemberton <wfp5p@virginia.edu>
Acked-by: Peter Korsgaard <peter.korsgaard@barco.com> (for ocores and mux-gpio)
Acked-by: Havard Skinnemoen <hskinnemoen@gmail.com> (for i2c-gpio)
Acked-by: Guan Xuetao <gxt@mprc.pku.edu.cn> (for puf3)
Acked-by: Barry Song <baohua.song@csr.com> (for sirf)
Reviewed-by: Jean Delvare <khali@linux-fr.org>
[wsa: Fixed "foo* bar" flaws while we are here]
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

i2c: mxs: Handle i2c DMA failure properly

Properly terminate the DMA transfer in case the DMA PIO transfer
or setup fails for any reason.

Signed-off-by: Marek Vasut <marex@denx.de>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

i2c: mxs: Do not disable the I2C SMBus quick mode

There is no reason to disable the I2C SMBus quick mode on this
IP block. Enable it. This essentially fixes the problem with the
"i2c-detect" command for probing the bus.

Signed-off-by: Marek Vasut <marex@denx.de>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

i2c: mxs: Handle i2c DMA failure properly

Properly terminate the DMA transfer in case the DMA PIO transfer
or setup fails for any reason.

Signed-off-by: Marek Vasut <marex@denx.de>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

i2c: mxs: remove broken PIOQUEUE support

This I2C master can do DMA and PIOQUEUE (PIO with FIFO). Originally,
only PIOQUEUE was supported and it had issues, then DMA support was added
this cycle. The original intention was to keep PIOQUEUE since it has
less overhead what is nice for small transfers. However, runtime
switching between PIOQEUE and DMA depending on the transfer size never
worked despite a lot of trying. Since PIOQUEUE mode itself was flaky
(polling at places where interrupts failed to work) and the
implementation also imposed a size limit for transfers, it is best to
remove the support, so users don't fall over its limitations. It also
makes the driver a lot cleaner and more robust. If somebody really wants
less overhead, plain PIO mode could still be implemented with the
addidtional advantage that this mode is also available on MX23, too.

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Reviewed-by: Marek Vasut <marex@denx.de>

MXS: Implement DMA support into mxs-i2c

This patch implements DMA support into mxs-i2c. DMA transfers are now enabled
via DT. The DMA operation is enabled by default.

Signed-off-by: Marek Vasut <marex@denx.de>
Tested-by: Fabio Estevam <fabio.estevam@freescale.com>

[wsa: rebased to 3.6-rc7]

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

i2c: mxs: correctly setup speed for non devicetree

Commit cd4f2d4 (i2c: mxs: Set I2C timing registers for mxs-i2c) only
covered the case for devicetree and made platform_data based boards
bail out with -EINVAL. Correctly support the latter one, too.

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

i2c: mxs: Set I2C timing registers for mxs-i2c

This patch configures the I2C bus timing registers according
to information passed via DT. Currently, 100kHz and 400kHz
modes are supported.

The TIMING2 register value is wrong in the documentation for
i.MX28! This was found and fixed by:
Shawn Guo <shawn.guo@linaro.org>

Signed-off-by: Marek Vasut <marex@denx.de>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

i2c: mxs: mxs_i2c_finish_read: mute flase positive uninitialized var

This patch mutes the false positive compiler warning:

drivers/i2c/busses/i2c-mxs.c: In function 'mxs_i2c_xfer_msg':
drivers/i2c/busses/i2c-mxs.c:206:8: warning: 'data' may be used uninitialized in this function [-Wuninitialized]
drivers/i2c/busses/i2c-mxs.c:196:6: note: 'data' was declared here

Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

i2c: mxs: add device tree probe support

Add device tree probe support for i2c-mxs driver. So far, it's only
been tested on imx28.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Acked-by: Wolfram Sang <w.sang@pengutronix.de>

i2c: mxs: adopt pinctrl support

Cc: linux-i2c@vger.kernel.org
Cc: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>

i2c: mxs: disable QUEUE when sending is done

Since the last fixes to this driver ensure now the queue termination is
done correctly, we can finally disable the queue after a transfer
without problems. The gain is that it will only be reenabled after the
next transfer is fully set up. Before, the queue was running all the
time and if the setup of the next message was interrupted by another
thread, an incomplete buffer could have been sent, padded with zeroes.

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

i2c: mxs: handle spurious interrupt

After an error interrupt setting cmd->err, I see another interrupt that
the data engine is empty which clears cmd->err before being processed.
So, clear cmd->err at the beginning of a transfer only to handle these
consecutive interrupts.

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

i2c: mxs: use global reset function

The former mach specific reset_block function has been converted to a global
one. Use the new one to remove mach dependency from the driver.

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

i2c: mxs: only flag completion when queue is completely done

The hardware generates an interrupt for every completed command in the
queue while the code assumed that it will only generate one interrupt
when the queue is empty. So, explicitly check if the queue is really
empty. This patch fixed problems which occurred due to high traffic on
the bus. While we are here, move the completion-initialization after the
parameter error checking.

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Cc: Shawn Guo <shawn.guo@linaro.org>
Cc: Marek Vasut <marek.vasut@gmail.com>
Cc: Lothar Waßmann <LW@KARO-electronics.de>
Cc: stable@kernel.org

Fix common misspellings

Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>

i2c-mxs: set controller to pio queue mode after reset

mxs_reset_block() clears the PIO_QUEUE_MODE bit. So we have
to set it again after a controller reset.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Cc: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>

i2c: add driver for Freescale i.MX28

Currently only supporting the PIOQUEUE-mode, because DMA-support for
this platform is not yet in mainline. When it becomes available and
support has been added to this driver, it will also be suitable for
i.MX23 and STMP3xxx.

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: Shawn Guo <shawn.guo@freescale.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>