backlight: ili922x: Add an error code check in ili922x_write()

Clang static analyzer complains that value stored to 'ret' is never read.
Return the error code when spi_sync() failed.

Signed-off-by: Su Hui <suhui@nfschina.com>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Link: https://lore.kernel.org/r/20231130051155.1235972-1-suhui@nfschina.com
Signed-off-by: Lee Jones <lee@kernel.org>

backlight: ili922x: Drop kernel-doc for local macros

Don't use kernel-doc notation for the local macros START_BYTE() and
CHECK_FREQ_REG(). This prevents these kernel-doc warnings:

ili922x.c:85: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
* START_BYTE(id, rs, rw)
ili922x.c:85: warning: missing initial short description on line:
* START_BYTE(id, rs, rw)
ili922x.c:118: warning: expecting prototype for CHECK_FREQ_REG(spi_device s, spi_transfer x)(). Prototype was for CHECK_FREQ_REG() instead

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Link: https://lore.kernel.org/r/20231206174525.14960-1-rdunlap@infradead.org
Signed-off-by: Lee Jones <lee@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>

backlight: ili922x: Add missing kerneldoc description for ili922x_reg_dump()'s arg

Kerneldoc syntax is used, but not complete. Descriptions required.

Prevents warnings like:

drivers/video/backlight/ili922x.c:298: warning: Function parameter or member 'spi' not described in 'ili922x_reg_dump'

Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Software Engineering <sbabic@denx.de>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

backlight: ili922x: Remove invalid use of kerneldoc syntax

Kerneldoc is for documenting function arguments and return values.

Prevents warnings like:

drivers/video/backlight/ili922x.c:127: warning: cannot understand function prototype: 'int ili922x_id = 1; '
drivers/video/backlight/ili922x.c:136: warning: cannot understand function prototype: 'struct ili922x '

Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Software Engineering <sbabic@denx.de>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

backlight: ili922x: Add missing kerneldoc descriptions for CHECK_FREQ_REG() args

Kerneldoc syntax is used, but not complete. Descriptions required.

Prevents warnings like:

drivers/video/backlight/ili922x.c:116: warning: Function parameter or member 's' not described in 'CHECK_FREQ_REG'
drivers/video/backlight/ili922x.c:116: warning: Function parameter or member 'x' not described in 'CHECK_FREQ_REG'

Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Software Engineering <sbabic@denx.de>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

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 either version 2 of the license or at
your option any later version

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

backlight: ili922x: Remove redundant variable len

The variable len is assigned but never read, therefore it is redundant
and can be removed. Cleans up clang warning:

drivers/video/backlight/ili922x.c:276:2: warning: Value stored to 'len'
is never read

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Acked-by: Jingoo Han <jingoohan1@gmail.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

spi: Drop owner assignment from spi_drivers

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

Signed-off-by: Andrew F. Davis <afd@ti.com>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

backlight: ili922x: Remove 'else' after a return

Fixed the following checkpatch warning.

WARNING: else is not generally useful after a break or return

Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

backlight: ili922x: remove unnecessary OOM messages

The site-specific OOM messages are unnecessary, because they duplicate
the MM subsystem generic OOM message.

Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Acked-by: Stefano Babic <sbabic@denx.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

backlight: ili922x: use devm_lcd_device_register()

Use devm_lcd_device_register() to make cleanup paths simpler.

Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

backlight: ili922x: use spi_set_drvdata()

Use the wrapper functions for getting and setting the driver data using
spi_device instead of using dev_{get|set}_drvdata with &spi->dev, so we
can directly pass a struct spi_device.

Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

video: backlight: add ili922x lcd driver

Add LCD driver for Ilitek ILI9221/ILI9222 controller. The driver uses
SPI interface for controller access and configuration and RGB interface
for graphics data transfer.

Signed-off-by: Stefano Babic <sbabic@denx.de>
Signed-off-by: Anatolij Gustschin <agust@denx.de>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Cc: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>