Input: applespi - use pm_sleep_ptr() and SYSTEM_SLEEP_PM_OPS()

SET_SYSTEM_SLEEP_PM_OPS() is deprecated as it requires explicit protection
against unused function warnings. The new combination of pm_sleep_ptr()
and SYSTEM_SLEEP_PM_OPS() allows the compiler to see the functions,
thus suppressing the warning, but still allowing the unused code to be
removed. Thus also drop the __maybe_unused markings.

In this case we also have a .poweroff_late() callback. Whilst not
strictly necessary, to future proof against relaxation of the protection
of the main driver.pm = pm_sleep_ptr() protect this pointer with
pm_sleep_ptr() as would be done if the LATE_SYSTEM_SLEEP_PM_OPS()
macro were used to set it.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/20230114171620.42891-13-jic23@kernel.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Input: applespi - replace zero-length array with DECLARE_FLEX_ARRAY() helper

Zero-length arrays are deprecated and we are moving towards adopting
C99 flexible-array members, instead. So, replace zero-length arrays
declarations in anonymous union with the new DECLARE_FLEX_ARRAY()
helper macro.

This helper allows for flexible-array members in unions.

Link: https://github.com/KSPP/linux/issues/193
Link: https://github.com/KSPP/linux/issues/219
Link: https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/YzIeJeqU73G+UI8g@work
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Input: applespi - use correct struct names in comment

The incorrect structure name is being used in the comment for struct
touchpad_info_protocol. Correct it.

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Link: https://lore.kernel.org/r/20220805174754.2374473-1-colin.i.king@gmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Input: applespi - avoid efivars API and invoke EFI services directly

This driver abuses the efivar API, by using a few of its helpers on
entries that were not instantiated by the API itself. This is a problem
as future cleanup work on efivars is complicated by this.

So let's just switch to the get/set variable runtime wrappers directly.

Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

spi: make remove callback a void function

The value returned by an spi driver's remove function is mostly ignored.
(Only an error message is printed if the value is non-zero that the
error is ignored.)

So change the prototype of the remove function to return no value. This
way driver authors are not tempted to assume that passing an error to
the upper layer is a good idea. All drivers are adapted accordingly.
There is no intended change of behaviour, all callbacks were prepared to
return 0 before.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Marc Kleine-Budde <mkl@pengutronix.de>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Acked-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Claudius Heine <ch@denx.de>
Acked-by: Stefan Schmidt <stefan@datenfreihafen.org>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # For MMC
Acked-by: Marcus Folkesson <marcus.folkesson@gmail.com>
Acked-by: Łukasz Stelmach <l.stelmach@samsung.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20220123175201.34839-6-u.kleine-koenig@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>

Input: applespi - fix occasional crc errors under load.

For some reason, when the system is under heavy CPU load, the read
following the write sometimes occurs unusually quickly, resulting in
the read data not being quite ready and hence a bad packet getting read.
Adding another delay after reading the status message appears to fix
this.

Signed-off-by: Ronald Tschalär <ronald@innovation.ch>
Link: https://lore.kernel.org/r/20210217190718.11035-2-ronald@innovation.ch
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Input: applespi - don't wait for responses to commands indefinitely.

The response to a command may never arrive or it may be corrupted (and
hence dropped) for some reason. While exceedingly rare, when it did
happen it blocked all further commands. One way to fix this was to
do a suspend/resume. However, recovering automatically seems like a
nicer option. Hence this puts a time limit (1 sec) on how long we're
willing to wait for a response, after which we assume it got lost.

Signed-off-by: Ronald Tschalär <ronald@innovation.ch>
Link: https://lore.kernel.org/r/20210217190718.11035-1-ronald@innovation.ch
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Input: applespi - use new structure for SPI transfer delays

In a recent change to the SPI subsystem [1], a new `delay` struct was added
to replace the `delay_usecs`. This change replaces the current
`delay_usecs` with `delay` for this driver.

The `spi_transfer_delay_exec()` function [in the SPI framework] makes sure
that both `delay_usecs` & `delay` are used (in this order to preserve
backwards compatibility).

[1] commit bebcfd272df6 ("spi: introduce `delay` field for
`spi_transfer` + spi_transfer_delay_exec()")

Signed-off-by: Sergiu Cuciurean <sergiu.cuciurean@analog.com>
Tested-by: Ronald Tschalär <ronald@innovation.ch>
Reviewed-by: Ronald Tschalär <ronald@innovation.ch>
Link: https://lore.kernel.org/r/20200227124534.23399-1-sergiu.cuciurean@analog.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Input: applespi - provide missing struct 'message' descriptions

Fixes the following W=1 kernel build warning(s):

drivers/input/keyboard/applespi.c:306: warning: Function parameter or member 'keyboard' not described in 'message'
drivers/input/keyboard/applespi.c:306: warning: Function parameter or member 'touchpad' not described in 'message'
drivers/input/keyboard/applespi.c:306: warning: Function parameter or member 'tp_info' not described in 'message'
drivers/input/keyboard/applespi.c:306: warning: Function parameter or member 'tp_info_command' not described in 'message'
drivers/input/keyboard/applespi.c:306: warning: Function parameter or member 'init_mt_command' not described in 'message'
drivers/input/keyboard/applespi.c:306: warning: Function parameter or member 'capsl_command' not described in 'message'
drivers/input/keyboard/applespi.c:306: warning: Function parameter or member 'bl_command' not described in 'message'
drivers/input/keyboard/applespi.c:306: warning: Function parameter or member 'data' not described in 'message'

Signed-off-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20201112110204.2083435-15-lee.jones@linaro.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Input: applespi - replace zero-length array with flexible-array

The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
int stuff;
struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

sizeof(flexible-array-member) triggers a warning because flexible array
members have incomplete type[1]. There are some instances of code in
which the sizeof operator is being incorrectly/erroneously applied to
zero-length arrays and the result is zero. Such instances may be hiding
some bugs. So, this work (flexible-array member conversions) will also
help to get completely rid of those sorts of issues.

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/20200507185347.GA14499@embeddedor
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Input: applespi - no need to check return value of debugfs_create functions

When calling debugfs functions, there is no need to ever check the
return value. The function can work or not, but the code logic should
never do something different based on this.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Input: applespi - use struct_size() helper

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 touchpad_protocol {
...
struct tp_finger fingers[0];
};

Make use of the struct_size() helper instead of an open-coded version
in order to avoid any potential type mistakes.

So, replace the following form:

sizeof(*tp) + tp->number_of_fingers * sizeof(tp->fingers[0]);

with:

struct_size(tp, fingers, tp->number_of_fingers)

This code was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Input: applespi - fix trivial typo in struct description

This fixes a typo in the keyboard_protocol description.
coodinate -> coordinate.

Signed-off-by: Nikolas Nyby <nikolas@gnu.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Input: applespi - fix warnings detected by sparse

This makes sure that we convert from on-wire to CPU endianness in
applespi_debug_update_dimensions() and also marks as "static" as it is not
needed to be visible outside of the driver.

Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Ronald Tschalär <ronald@innovation.ch>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Input: applespi - remove set but not used variables 'sts'

Fixes gcc '-Wunused-but-set-variable' warning:

drivers/input/keyboard/applespi.c: In function applespi_set_bl_level:
drivers/input/keyboard/applespi.c:902:6: warning: variable sts set but not used [-Wunused-but-set-variable]

Fixes: b426ac0452093d ("Input: add Apple SPI keyboard and trackpad driver")
Signed-off-by: Mao Wenan <maowenan@huawei.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Input: add Apple SPI keyboard and trackpad driver

The keyboard and trackpad on recent MacBook's (since 8,1) and
MacBookPro's (13,* and 14,*) are attached to an SPI controller instead
of USB, as previously. The higher level protocol is not publicly
documented and hence has been reverse engineered. As a consequence there
are still a number of unknown fields and commands. However, the known
parts have been working well and received extensive testing and use.

In order for this driver to work, the proper SPI drivers need to be
loaded too; for MB8,1 these are spi_pxa2xx_platform and spi_pxa2xx_pci;
for all others they are spi_pxa2xx_platform and intel_lpss_pci.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=99891
Link: https://bugzilla.kernel.org/show_bug.cgi?id=108331
Signed-off-by: Ronald Tschalär <ronald@innovation.ch>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>