The default-on property - or the def_value via legacy pdata) should be
handled as:
if it is 1, the backlight must be enabled (kept enabled)
if it is 0, the backlight must be disabled (kept disabled)
This only works for the case when default-on is set. If it is not set then
the brightness of the backlight is set to 0. Now if the backlight is
enabled by external driver (graphics) the backlight will stay disabled since
the brightness is configured as 0. The backlight will not turn on.
In order to minimize screen flickering during device boot:
The initial brightness should be set to 1.
If booted in non DT mode or no phandle link to the backlight node:
follow the def_value/default-on to select UNBLANK or POWERDOWN
If in DT boot we have phandle link then leave the GPIO in a state which the
bootloader left it and let the user of the backlight to configure it
further.
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
- Provide support for ACPI enumeration; gpio_backlight
- Fix-ups
- SPDX fixups; pwm_bl
- Fix linear brightness levels to include number available; pwm_bl
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Merge tag 'backlight-next-5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/backlight
Pull backlight updates from Lee Jones:
"New Functionality:
- Provide support for ACPI enumeration; gpio_backlight
Fix-ups:
- SPDX fixups; pwm_bl
- Fix linear brightness levels to include number available; pwm_bl"
* tag 'backlight-next-5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/backlight:
backlight: pwm_bl: Fix heuristic to determine number of brightness levels
backlight: gpio_backlight: Enable ACPI enumeration
backlight: pwm_bl: Convert to use SPDX identifier
ACPI allows to enumerate specific devices by using compatible strings.
Enable that enumeration for GPIO based backlight devices.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Based on 2 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 version 2 as
published by the free software foundation
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation #
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 4122 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The option to invert the output of the GPIO (active low) is
not used by the only platform still using platform data to
set up a GPIO backlight (one SH board). Delete the option
as we do not expect to expand the use of board files for
this driver, and GPIO descriptors intrinsically keep track
of any signal inversion.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
This driver is predominantly used by device tree systems, all
of which can deal with modern GPIO descriptors. The legacy
GPIO API is only used by one SH board so make the GPIO
descriptor the default way to deal with it.
As an intended side effect we do not need to look around in
the device tree for the inversion flag since the GPIO
descriptors will intrinsically deal with this.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
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>
Peter Ujfalusi