The gpio-backlight driver seems to be missing the
MODULE_DEVICE_TABLE line which is preventing it from
being modprobed during boot time even if the
gpio-backlight device exists.

This seems to be a bug and this patch attempts to
fix that.

Signed-off-by: Arun Bharadwaj <arun@gumstix.com>
Signed-off-by: Ash Charles <ashcharles@gmail.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

This patch removes the superflous .owner field for drivers which
use the module_platform_driver or platform_driver_register api,
as this is overriden in __platform_driver_register.

Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

Since backlight core returns props.brightness in case get_brightness
is not implemented trivial implementations are not needed anymore.

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

If the GPIO for the backlight is on an I2C chip, we currently
get nasty warnings like this during the boot:

WARNING: CPU: 0 PID: 6 at drivers/gpio/gpiolib.c:2364 gpiod_set_raw_value+0x40/0x4c()
Modules linked in:
CPU: 0 PID: 6 Comm: kworker/u2:0 Not tainted 3.15.0-rc4-12393-gcde9f4e #400
Workqueue: deferwq deferred_probe_work_func
[<c0014cbc>] (unwind_backtrace) from [<c001191c>] (show_stack+0x10/0x14)
[<c001191c>] (show_stack) from [<c0566ae0>] (dump_stack+0x80/0x9c)
[<c0566ae0>] (dump_stack) from [<c003f61c>] (warn_slowpath_common+0x68/0x8c)
[<c003f61c>] (warn_slowpath_common) from [<c003f65c>] (warn_slowpath_null+0x1c/0x24)
[<c003f65c>] (warn_slowpath_null) from [<c02f7e10>] (gpiod_set_raw_value+0x40/0x4c)
[<c02f7e10>] (gpiod_set_raw_value) from [<c0308fbc>] (gpio_backlight_update_status+0x4c/0x74)
[<c0308fbc>] (gpio_backlight_update_status) from [<c030914c>] (gpio_backlight_probe+0x168/0x254)
[<c030914c>] (gpio_backlight_probe) from [<c0378fa8>] (platform_drv_probe+0x18/0x48)
[<c0378fa8>] (platform_drv_probe) from [<c0377c40>] (driver_probe_device+0x10c/0x238)
[<c0377c40>] (driver_probe_device) from [<c0376330>] (bus_for_each_drv+0x44/0x8c)
[<c0376330>] (bus_for_each_drv) from [<c0377afc>] (device_attach+0x74/0x8c)
[<c0377afc>] (device_attach) from [<c03771c4>] (bus_probe_device+0x88/0xb0)
[<c03771c4>] (bus_probe_device) from [<c03775c8>] (deferred_probe_work_func+0x64/0x94)
[<c03775c8>] (deferred_probe_work_func) from [<c00572e8>] (process_one_work+0x1b4/0x4bc)
[<c00572e8>] (process_one_work) from [<c00579d0>] (worker_thread+0x11c/0x398)
[<c00579d0>] (worker_thread) from [<c005dfd8>] (kthread+0xc8/0xe4)
[<c005dfd8>] (kthread) from [<c000e768>] (ret_from_fork+0x14/0x2c)

Fix this by using gpio_set_value_cansleep() as suggested in
drivers/gpio/gpiolib.c:2364. This is what the other backlight drivers
are also doing.

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

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

Use devm_backlight_device_register() to make cleanup paths simpler, and
remove unnecessary remove().

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>

Use the wrapper function for retrieving the platform data instead of
accessing dev->platform_data directly.  This is a cosmetic change to
make the code simpler and enhance the readability.

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>

The GPIO backlight driver controls the backlight in on/off mode through
a single GPIO.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Acked-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>