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path: root/drivers/video/backlight/gpio_backlight.c
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2024-03-07backlight: gpio: Simplify with dev_err_probe()Krzysztof Kozlowski
Common pattern of handling deferred probe can be simplified with dev_err_probe(). Less code and also it prints the error value. Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Link: https://lore.kernel.org/r/20240305-backlight-probe-v2-1-609b0cf24bde@linaro.org Signed-off-by: Lee Jones <lee@kernel.org>
2023-09-06Merge tag 'backlight-next-6.6' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/lee/backlight Pull backlight updates from Lee Jones: "New Functionality: - Ensure correct includes are present and remove some that are not required - Drop redundant of_match_ptr() call to cast pointer to NULL Bug Fixes: - Revert to old (expected) behaviour of initialising PWM state on first brightness change - Correctly handle / propagate errors - Fix 'sometimes-uninitialised' issues" * tag 'backlight-next-6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/backlight: backlight: led_bl: Remove redundant of_match_ptr() backlight: lp855x: Drop ret variable in brightness change function backlight: gpio_backlight: Drop output GPIO direction check for initial power state backlight: lp855x: Catch errors when changing brightness backlight: lp855x: Initialize PWM state on first brightness change backlight: qcom-wled: Explicitly include correct DT includes
2023-07-28backlight: gpio_backlight: Drop output GPIO direction check for initial ↵Ying Liu
power state So, let's drop output GPIO direction check and only check GPIO value to set the initial power state. Fixes: 706dc68102bc ("backlight: gpio: Explicitly set the direction of the GPIO") Signed-off-by: Liu Ying <victor.liu@nxp.com> Reviewed-by: Andy Shevchenko <andy@kernel.org> Acked-by: Linus Walleij <linus.walleij@linaro.org> Acked-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org> Link: https://lore.kernel.org/r/20230721093342.1532531-1-victor.liu@nxp.com Signed-off-by: Lee Jones <lee@kernel.org>
2023-06-27backlight/gpio_backlight: Rename field 'fbdev' to 'dev'Thomas Zimmermann
Rename the field 'fbdev' in struct gpio_backlight_platform_data and struct gpio_backlight to 'dev', as they store pointers to the Linux platform device; not the fbdev device. Makes the code easier to understand. Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> Cc: Rich Felker <dalias@libc.org> Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de> Cc: Lee Jones <lee@kernel.org> Cc: Daniel Thompson <daniel.thompson@linaro.org> Cc: Jingoo Han <jingoohan1@gmail.com> Cc: linux-sh@vger.kernel.org Reviewed-by: Sam Ravnborg <sam@ravnborg.org> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Link: https://patchwork.freedesktop.org/patch/msgid/20230613110953.24176-5-tzimmermann@suse.de
2023-06-27backlight/gpio_backlight: Compare against struct fb_info.deviceThomas Zimmermann
Struct gpio_backlight_platform_data refers to a platform device within the Linux device hierarchy. The test in gpio_backlight_check_fb() compares it against the fbdev device in struct fb_info.dev, which is different. Fix the test by comparing to struct fb_info.device. Fixes a bug in the backlight driver and prepares fbdev for making struct fb_info.dev optional. v2: * move renames into separate patch (Javier, Sam, Michael) Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> Fixes: 8b770e3c9824 ("backlight: Add GPIO-based backlight driver") Cc: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> Cc: Rich Felker <dalias@libc.org> Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de> Cc: Lee Jones <lee@kernel.org> Cc: Daniel Thompson <daniel.thompson@linaro.org> Cc: Jingoo Han <jingoohan1@gmail.com> Cc: linux-sh@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Cc: <stable@vger.kernel.org> # v3.12+ Reviewed-by: Sam Ravnborg <sam@ravnborg.org> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Link: https://patchwork.freedesktop.org/patch/msgid/20230613110953.24176-4-tzimmermann@suse.de
2020-07-20backlight: gpio_backlight: Simplify update_status()Sam Ravnborg
Introduce the use of backlight_get_brightness() to simplify the update_status() operation. With the simpler implementation drop the gpio_backlight_get_next_brightness() helper as it was now a one-liner. Signed-off-by: Sam Ravnborg <sam@ravnborg.org> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Lee Jones <lee.jones@linaro.org>
2019-11-11backlight: gpio: Pull gpio_backlight_initial_power_state() into probeBartosz Golaszewski
The probe function in the gpio-backlight driver is quite short. If we pull gpio_backlight_initial_power_state() into probe we can drop two more fields from struct gpio_backlight and shrink the driver code. Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com> Acked-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Lee Jones <lee.jones@linaro.org>
2019-11-11backlight: gpio: Use a helper variable for &pdev->devBartosz Golaszewski
Instead of dereferencing pdev each time, use a helper variable for the associated device pointer. Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Lee Jones <lee.jones@linaro.org>
2019-11-11backlight: gpio: Simplify the platform data handlingBartosz Golaszewski
Now that the last user of platform data (sh ecovec24) defines a proper GPIO lookup and sets the 'default-on' device property, we can drop the platform_data-specific GPIO handling and unify a big chunk of code. The only field used from the platform data is now the fbdev pointer. Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Lee Jones <lee.jones@linaro.org>
2019-11-11backlight: gpio: Explicitly set the direction of the GPIOBartosz Golaszewski
The GPIO backlight driver currently requests the line 'as is', without acively setting its direction. This can lead to problems: if the line is in input mode by default, we won't be able to drive it later when updating the status and also reading its initial value doesn't make sense for backlight setting. Request the line 'as is' initially, so that we can read its value without affecting it but then change the direction to output explicitly when setting the initial brightness. Also: check the current direction and only read the value if it's output. Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Lee Jones <lee.jones@linaro.org>
2019-11-11backlight: gpio: Remove stray newlineBartosz Golaszewski
Remove a double newline from the driver. Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Lee Jones <lee.jones@linaro.org>
2019-11-11backlight: gpio: Remove unneeded includeBartosz Golaszewski
We no longer use any symbols from of_gpio.h. Remove this include. Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Lee Jones <lee.jones@linaro.org>
2019-09-02backlight: gpio-backlight: Correct initial power state handlingPeter Ujfalusi
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>
2019-07-16Merge tag 'backlight-next-5.3' of ↵Linus Torvalds
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
2019-06-27backlight: gpio_backlight: Enable ACPI enumerationAndy Shevchenko
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>
2019-06-19treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500Thomas Gleixner
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>
2017-08-07backlight: gpio_backlight: Delete pdata inversionLinus Walleij
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>
2017-08-07backlight: gpio_backlight: Convert to use GPIO descriptorLinus Walleij
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>
2016-01-11backlight: gpio-backlight: Use default-on on GPIO requestStefan Agner
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>
2015-06-23gpio-backlight: Discover driver during boot timeArun Bharadwaj
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>
2014-08-28backlight: Remove .owner field for drivers using module_platform_driverPeter Griffin
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>
2014-06-23backlight: Remove trivial get_brightness implementationsAndrzej Hajda
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>
2014-06-05backlight: gpio-backlight: Fix warning when the GPIO is on a I2C chipTony Lindgren
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>
2014-04-08backlight: gpio-backlight: Add DT supportDenis Carikli
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>
2013-11-13backlight: gpio_backlight: use devm_backlight_device_register()Jingoo Han
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>
2013-11-13backlight: use dev_get_platdata()Jingoo Han
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>
2013-07-16backlight: Add GPIO-based backlight driverLaurent Pinchart
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>