i2c: mux: demux-pinctrl: Convert to use sysfs_emit_at() API

Follow the advice of the Documentation/filesystems/sysfs.rst and show()
should only use sysfs_emit() or sysfs_emit_at() when formatting the
value to be returned to user space.

Signed-off-by: ye xingchen <ye.xingchen@zte.com.cn>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
[wsa: proper subject prefix]
Signed-off-by: Wolfram Sang <wsa@kernel.org>

i2c: mux: demux-pinctrl: Annotate struct i2c_demux_pinctrl_priv with __counted_by

Prepare for the coming implementation by GCC and Clang of the __counted_by
attribute. Flexible array members annotated with __counted_by can have
their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
(for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).

As found with Coccinelle[1], add __counted_by for struct i2c_demux_pinctrl_priv.
Additionally, since the element count member must be set before accessing
the annotated flexible array member, move its initialization earlier.

[1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci

Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
[wsa: improved blank lines]
Signed-off-by: Wolfram Sang <wsa@kernel.org>

i2c: muxes: i2c-demux-pinctrl: Use of_get_i2c_adapter_by_node()

i2c-demux-pinctrl uses the pair of_find_i2c_adapter_by_node() /
i2c_put_adapter(). These pair alone is not correct to properly lock the
I2C parent adapter.

Indeed, i2c_put_adapter() decrements the module refcount while
of_find_i2c_adapter_by_node() does not increment it. This leads to an
underflow of the parent module refcount.

Use the dedicated function, of_get_i2c_adapter_by_node(), to handle
correctly the module refcount.

Fixes: 50a5ba876908 ("i2c: mux: demux-pinctrl: add driver")
Signed-off-by: Herve Codina <herve.codina@bootlin.com>
Cc: stable@vger.kernel.org
Acked-by: Peter Rosin <peda@axentia.se>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

i2c: mux: demux-pinctrl: check the return value of devm_kstrdup()

devm_kstrdup() returns pointer to allocated string on success,
NULL on failure. So it is better to check the return value of it.

Fixes: e35478eac030 ("i2c: mux: demux-pinctrl: run properly with multiple instances")
Signed-off-by: Xiaoke Wang <xkernel.wang@foxmail.com>
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: mux: demux-pinctrl: do not deactivate a master that is not active

Attempting to rollback the activation of the current master when
the current master has not been activated is bad. priv->cur_chan
and priv->cur_adap are both still zeroed out and the rollback
may result in attempts to revert an of changeset that has not been
applied and do result in calls to both del and put the zeroed out
i2c_adapter. Maybe it crashes, or whatever, but it's bad in any
case.

Fixes: e9d1a0a41d44 ("i2c: mux: demux-pinctrl: Fix an error handling path in 'i2c_demux_pinctrl_probe()'")
Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

i2c: mux: demux-pinctrl: Fix an error handling path in 'i2c_demux_pinctrl_probe()'

A call to 'i2c_demux_deactivate_master()' is missing in the error handling
path, as already done in the remove function.

Fixes: 50a5ba876908 ("i2c: mux: demux-pinctrl: add driver")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation version 2 of the license

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 315 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Armijn Hemel <armijn@tjaldur.nl>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190531190115.503150771@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

i2c: mux: demux-pinctrl: use struct_size() in devm_kzalloc()

One of the more common cases of allocation size calculations is finding
the size of a structure that has a zero-sized array at the end, along
with memory for some number of elements for that array. For example:

struct foo {
int stuff;
void *entry[];
};

instance = devm_kzalloc(dev, sizeof(struct foo) + sizeof(void *) * count, GFP_KERNEL);

Instead of leaving these open-coded and prone to type mistakes, we can
now use the new struct_size() helper:

instance = devm_kzalloc(dev, struct_size(instance, entry, count), GFP_KERNEL);

This code was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Acked-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Peter Rosin <peda@axentia.se>

i2c: demux: handle the new atomic callbacks

If the parent has an atomic callback, we need to translate it the same
way as the non-atomic callback.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

i2c: mux: demux-pinctrl: use proper parent device for demux adapter

Due to a typo, the wrong parent device was assigned to the newly created
demuxing adapter device. It got connected to the demuxing platform
device but not to the selected parent I2C adapter device. Fix it to get
a proper parent-child relationship of the demuxed busses.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Peter Rosin <peda@axentia.se>

i2c: mux: demux-pinctrl: disable PM user interface

The demux device is only a logical device with no children. So, no
RuntimePM is needed, let's disable the sysfs interface for it.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Peter Rosin <peda@axentia.se>

i2c: Convert to using %pOF instead of full_name

Now that we have a custom printf format specifier, convert users of
full_name to use %pOF instead. This is preparation to remove storing
of the full path string for each node.

Signed-off-by: Rob Herring <robh@kernel.org>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

i2c: mux: demux-pinctrl: make drivers with no pinctrl work again

Some drivers like i2c-gpio do not have dedicated pinctrl states. They
broke when error checking for pinctrl was added. Detect them now, and in
their case, simply skip over pinctrl configuration.

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

i2c: mux: demux-pinctrl: run properly with multiple instances

We can't use a static property for all the changesets, so we now create
dynamic ones for each changeset.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Fixes: 50a5ba87690814 ("i2c: mux: demux-pinctrl: add driver")
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

i2c: mux: demux-pinctrl: invalidate properly when switching fails

Make sure the index to the active channel is invalidated when switching
fails.

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

i2c: mux: demux-pinctrl: properly roll back when adding adapter fails

We also need to revert the dynamic OF change, so we get a consistent
state again. Otherwise, we might have two devices enabled e.g. after
pinctrl setup fails.

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

i2c: mux: demux-pinctrl: Clean up sysfs attributes

sysfs attributes should use the same format for reads and writes,
rather than pretty-printing on read.

* Make the "cur_master" attribute read back as just the name of the
master
* Expose the list of all masters as a read-only "available_masters"
attribute, using space separators as in similar attributes of other
devices

Also, spell out "cur_master" in full as "current_master".

Fixes: 50a5ba876908 ("i2c: mux: demux-pinctrl: add driver")
Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

i2c: mux: demux-pinctrl: add driver

This driver allows an I2C bus to switch between multiple masters. This
is not hot-switching because connected I2C slaves will be
re-instantiated. It is meant to select the best I2C core at runtime once
the task is known. Example: Prefer i2c-gpio over another I2C core
because of HW errata affecting your use case.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>