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: cros-ec-tunnel: Mark ACPI and OF related data as maybe unused

The driver can be compile tested with !CONFIG_OF or !CONFIG_ACPI making
certain data unused:

drivers/i2c/busses/i2c-cros-ec-tunnel.c:295:34: error: ‘cros_ec_i2c_of_match’ defined but not used [-Werror=unused-const-variable=]

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Guenter Roeck <groeck@chromium.org>
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: cros-ec-tunnel: Fix syntax errors in comments

Delete the redundant word 'to'

Signed-off-by: Xiang wangx <wangxiang@cdjrlc.com>
[wsa: fixed prefix in subject]
Signed-off-by: Wolfram Sang <wsa@kernel.org>

i2c: cros-ec-tunnel: Fix ACPI identifier

The initial patch was using the incorrect identifier.

Fixes: 9af1563a5486 ("i2c: cros-ec-tunnel: Make the device acpi compatible")
Signed-off-by: Raul E Rangel <rrangel@chromium.org>
Acked-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

i2c: cros-ec-tunnel: Fix slave device enumeration

During adding of the adapter the slave device registration
use to fail as the acpi companion field was not populated.

Fixes: 9af1563a5486 ("i2c: cros-ec-tunnel: Make the device acpi compatible")
Signed-off-by: Akshu Agrawal <akshu.agrawal@amd.com>
Acked-by: Raul E Rangel <rrangel@chromium.org>
Reviewed-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

i2c: cros-ec-tunnel: Make the device acpi compatible

Add ACPI entry and use device_property_read to get fw value
which is common to both dtsi and acpi.

Signed-off-by: Akshu Agrawal <akshu.agrawal@amd.com>
Acked-by: Raul E Rangel <rrangel@chromium.org>
Reviewed-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

mfd / platform: cros_ec: Reorganize platform and mfd includes

There is a bit of mess between cros-ec mfd includes and platform
includes. For example, we have a linux/mfd/cros_ec.h include that
exports the interface implemented in platform/chrome/cros_ec_proto.c. Or
we have a linux/mfd/cros_ec_commands.h file that is non related to the
multifunction device (in the sense that is not exporting any function of
the mfd device). This causes crossed includes between mfd and
platform/chrome subsystems and makes the code difficult to read, apart
from creating 'curious' situations where a platform/chrome driver includes
a linux/mfd/cros_ec.h file just to get the exported functions that are
implemented in another platform/chrome driver.

In order to have a better separation on what the cros-ec multifunction
driver does and what the cros-ec core provides move and rework the
affected includes doing:

- Move cros_ec_commands.h to include/linux/platform_data/cros_ec_commands.h
- Get rid of the parts that are implemented in the platform/chrome/cros_ec_proto.c
driver from include/linux/mfd/cros_ec.h to a new file
include/linux/platform_data/cros_ec_proto.h
- Update all the drivers with the new includes, so
- Drivers that only need to know about the protocol include
- linux/platform_data/cros_ec_proto.h
- linux/platform_data/cros_ec_commands.h
- Drivers that need to know about the cros-ec mfd device also include
- linux/mfd/cros_ec.h

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Mark Brown <broonie@kernel.org>
Acked-by: Wolfram Sang <wsa@the-dreams.de>
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Acked-by: Chanwoo Choi <cw00.choi@samsung.com>
Reviewed-by: Gwendal Grignou <gwendal@chromium.org>
Tested-by: Gwendal Grignou <gwendal@chromium.org>
Series changes: 3
- Fix dereferencing pointer to incomplete type 'struct cros_ec_dev' (lkp)
Signed-off-by: Lee Jones <lee.jones@linaro.org>

i2c: i2c-cros-ec-tunnel: Switch to SPDX identifier.

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

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

i2c: i2c-cros-ec-tunnel: Reduce logging noise

If an i2c access through i2c-cros-ec-tunnel returns an error, the following
log message is seen on the console.

cros-ec-i2c-tunnel ff200000.spi:ec@0:i2c-tunnel:
Error parsing EC i2c message -121

This can happen a lot if, for example, the i2c-detect command is executed.

Since it is perfectly normal for an i2c controller to report an error,
drop the message. Also, report -ENXIO instead of -EREMOTEIO if the access
error is due to NAK from the device, and return -EIO instead of -EREMOTEIO
for other errors, as suggested in Documentation/i2c/fault-codes.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
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: cros-ec-tunnel: Fix usage of cros_ec_cmd_xfer()

cros_ec_cmd_xfer returns success status if the command transport
completes successfully, but the execution result is incorrectly ignored.
In many cases, the execution result is assumed to be successful, leading
to ignored errors and operating on uninitialized data.

We've recently introduced the cros_ec_cmd_xfer_status() helper to avoid these
problems. Let's use it.

[Regarding the 'Fixes' tag; there is significant refactoring since the driver's
introduction, but the underlying logical error exists throughout I believe]

Fixes: 9d230c9e4f4e ("i2c: ChromeOS EC tunnel driver")
Cc: <stable@vger.kernel.org> # 9798ac6d32c1 mfd: cros_ec: Add cros_ec_cmd_xfer_status() helper
Signed-off-by: Brian Norris <briannorris@chromium.org>
Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

mfd: cros_ec: Use a zero-length array for command data

Commit 1b84f2a4cd4a ("mfd: cros_ec: Use fixed size arrays to transfer
data with the EC") modified the struct cros_ec_command fields to not
use pointers for the input and output buffers and use fixed length
arrays instead.

This change was made because the cros_ec ioctl API uses that struct
cros_ec_command to allow user-space to send commands to the EC and
to get data from the EC. So using pointers made the API not 64-bit
safe. Unfortunately this approach was not flexible enough for all
the use-cases since there may be a need to send larger commands
on newer versions of the EC command protocol.

So to avoid to choose a constant length that it may be too big for
most commands and thus wasting memory and CPU cycles on copy from
and to user-space or having a size that is too small for some big
commands, use a zero-length array that is both 64-bit safe and
flexible. The same buffer is used for both output and input data
so the maximum of these values should be used to allocate it.

Suggested-by: Gwendal Grignou <gwendal@chromium.org>
Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

mfd: cros_ec: Use fixed size arrays to transfer data with the EC

The struct cros_ec_command will be used as an ioctl() argument for the
API to control the ChromeOS EC from user-space. So the data structure
has to be 64-bit safe to make it compatible between 32 and 64 avoiding
the need for a compat ioctl interface. Since pointers are self-aligned
to different byte boundaries, use fixed size arrays instead of pointers
for transferring ingoing and outgoing data with the Embedded Controller.

Also, re-arrange struct members by decreasing alignment requirements to
reduce the needing padding size.

Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Acked-by: Lee Jones <lee.jones@linaro.org>
Tested-by: Gwendal Grignou <gwendal@chromium.org>
Reviewed-by: Gwendal Grignou <gwendal@chromium.org>
Signed-off-by: Olof Johansson <olof@lixom.net>

i2c: i2c-cros-ec-tunnel: Set retries to 3

Since the i2c bus can get wedged on the EC sometimes, set the number of retries
to 3. Since we un-wedge the bus immediately after the wedge happens, this is the
correct fix since only one transfer will fail.

Signed-off-by: Derek Basehore <dbasehore@chromium.org>
Reviewed-by: Doug Anderson <dianders@chromium.org>
Acked-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

mfd: cros_ec: stop calling ->cmd_xfer() directly

Instead of having users of the ChromeOS EC call the interface-specific
cmd_xfer() callback directly, introduce a central cros_ec_cmd_xfer()
to use instead. This will allow us to put all the locking and retry
logic in one place instead of duplicating it across the different
drivers.

Signed-off-by: Andrew Bresticker <abrestic@chromium.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Reviewed-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

i2c: cros_ec: Remove EC_I2C_FLAG_10BIT

In <https://lkml.org/lkml/2014/6/10/265> pointed out that the 10-bit
flag in the cros_ec_tunnel was useless. It went into a 16-bit flags
field but was defined at (1 << 16).

Since we have no 10-bit i2c devices on the other side of the tunnel on
any known devices this was never a problem. Until we do it makes
sense to remove this code. On the EC side the code to handle this
flag was removed in <https://chromium-review.googlesource.com/204162>.

Reported-by: Dave Jones <davej@redhat.com>
Signed-off-by: Doug Anderson <dianders@chromium.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

i2c: cros-ec-tunnel: Add of match table

To enable the cros-ec-tunnel driver to be auto-loaded when build as a
module add an of match table (and export it) to match the modalias
information passed on to userspace as the Cros EC MFD driver registers
the MFD subdevices with an of_compatibility string.

Signed-off-by: Sjoerd Simons <sjoerd.simons@collabora.co.uk>
Reviewed-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

mfd: cros_ec: ec_dev->cmd_xfer() returns number of bytes received from EC

When communicating with the EC, the cmd_xfer() function should return the
number of bytes it received from the EC, or negative on error.

Signed-off-by: Bill Richardson <wfrichar@chromium.org>
Signed-off-by: Doug Anderson <dianders@chromium.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
Acked-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

mfd: cros_ec: cleanup: Remove EC wrapper functions

Remove the three wrapper functions that talk to the EC without passing all
the desired arguments and just use the underlying communication function
that passes everything in a struct intead.

This is internal code refactoring only. Nothing should change.

Signed-off-by: Bill Richardson <wfrichar@chromium.org>
Signed-off-by: Doug Anderson <dianders@chromium.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
Acked-by: Wolfram Sang <wsa@the-dreams.de>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

i2c: ChromeOS EC tunnel driver

On ARM Chromebooks we have a few devices that are accessed by both the
AP (the main "Application Processor") and the EC (the Embedded
Controller). These are:
* The battery (sbs-battery).
* The power management unit tps65090.

On the original Samsung ARM Chromebook these devices were on an I2C
bus that was shared between the AP and the EC and arbitrated using
some extranal GPIOs (see i2c-arb-gpio-challenge).

The original arbitration scheme worked well enough but had some
downsides:
* It was nonstandard (not using standard I2C multimaster)
* It only worked if the EC-AP communication was I2C
* It was relatively hard to debug problems (hard to tell if i2c issues
were caused by the EC, the AP, or some device on the bus).

On the HP Chromebook 11 the design was changed to:
* The AP/EC comms were still i2c, but the battery/tps65090 were no
longer on the bus used for AP/EC communication. The battery was
exposed to the AP through a limited i2c tunnel and tps65090 was
exposed to the AP through a custom Linux driver.

On the Samsung ARM Chromebook 2 the scheme is changed yet again, now:
* The AP/EC comms are now using SPI for faster speeds.
* The EC's i2c bus is exposed to the AP through a full i2c tunnel.

The upstream "tegra124-venice2" uses the same scheme as the Samsung
ARM Chromebook 2, though it has a different set of components on the
other side of the bus.

This driver supports the scheme used by the Samsung ARM Chromebook 2.
Future patches to this driver could add support for the battery tunnel
on the HP Chromebook 11 (and perhaps could even be used to access
tps65090 on the HP Chromebook 11 instead of using a special driver,
but I haven't researched that enough).

Signed-off-by: Vincent Palatin <vpalatin@chromium.org>
Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Doug Anderson <dianders@chromium.org>
Reviewed-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Lee Jones <lee.jones@linaro.org>