There are situations where the backlight should be on at boot time
(e.g. if the boot loader already turned the display on). The DT
bindings specify the "default-on" property for that purpose.
Currently, the initial state of the GPIO at request time is always
set to logical off (high or low depending on whether it is an
active high or low GPIO). Since the GPIO is requested as an output,
the GPIO will be driven low for a short period of time, which leads
to a flickering display in the above use-case.
Initialize the GPIO depending on the default-on property to be
logical on or off.
Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
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>
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>
Stefan Agner