kernel/linux.git/drivers/video/backlight, branch v4.14.263

backlight: pwm_bl: Improve bootloader/kernel device handover

2021-09-22T09:45:23+00:00

commit 79fad92f2e596f5a8dd085788a24f540263ef887 upstream. Currently there are (at least) two problems in the way pwm_bl starts managing the enable_gpio pin. Both occur when the backlight is initially off and the driver finds the pin not already in output mode and, as a result, unconditionally switches it to output-mode and asserts the signal. Problem 1: This could cause the backlight to flicker since, at this stage in driver initialisation, we have no idea what the PWM and regulator are doing (an unconfigured PWM could easily "rest" at 100% duty cycle). Problem 2: This will cause us not to correctly honour the post_pwm_on_delay (which also risks flickers). Fix this by moving the code to configure the GPIO output mode until after we have examines the handover state. That allows us to initialize enable_gpio to off if the backlight is currently off and on if the backlight is on. Cc: stable@vger.kernel.org Reported-by: Marek Vasut Signed-off-by: Daniel Thompson Acked-by: Marek Vasut Tested-by: Marek Vasut Signed-off-by: Lee Jones Signed-off-by: Greg Kroah-Hartman

backlight: lm3630a: Fix return code of .update_status() callback

2021-07-20T14:17:51+00:00

[ Upstream commit b9481a667a90ec739995e85f91f3672ca44d6ffa ] According to .update_status() is supposed to return 0 on success and a negative error code otherwise. Adapt lm3630a_bank_a_update_status() and lm3630a_bank_b_update_status() to actually do it. While touching that also add the error code to the failure message. Signed-off-by: Uwe Kleine-König Reviewed-by: Daniel Thompson Signed-off-by: Lee Jones Signed-off-by: Sasha Levin

backlight: sky81452-backlight: Fix refcount imbalance on error

2020-10-29T08:07:04+00:00

[ Upstream commit b7a4f80bc316a56d6ec8750e93e66f42431ed960 ] When of_property_read_u32_array() returns an error code, a pairing refcount decrement is needed to keep np's refcount balanced. Fixes: f705806c9f355 ("backlight: Add support Skyworks SKY81452 backlight driver") Signed-off-by: Dinghao Liu Reviewed-by: Daniel Thompson Signed-off-by: Lee Jones Signed-off-by: Sasha Levin

backlight: lp855x: Ensure regulators are disabled on probe failure

2020-06-25T13:41:47+00:00

[ Upstream commit d8207c155a7c6015eb7f43739baa7dfb1fa638af ] If probing the LP885x backlight fails after the regulators have been enabled, then the following warning is seen when releasing the regulators ... WARNING: CPU: 1 PID: 289 at drivers/regulator/core.c:2051 _regulator_put.part.28+0x158/0x160 Modules linked in: tegra_xudc lp855x_bl(+) host1x pwm_tegra ip_tables x_tables ipv6 nf_defrag_ipv6 CPU: 1 PID: 289 Comm: systemd-udevd Not tainted 5.6.0-rc2-next-20200224 #1 Hardware name: NVIDIA Jetson TX1 Developer Kit (DT) ... Call trace: _regulator_put.part.28+0x158/0x160 regulator_put+0x34/0x50 devm_regulator_release+0x10/0x18 release_nodes+0x12c/0x230 devres_release_all+0x34/0x50 really_probe+0x1c0/0x370 driver_probe_device+0x58/0x100 device_driver_attach+0x6c/0x78 __driver_attach+0xb0/0xf0 bus_for_each_dev+0x68/0xc8 driver_attach+0x20/0x28 bus_add_driver+0x160/0x1f0 driver_register+0x60/0x110 i2c_register_driver+0x40/0x80 lp855x_driver_init+0x20/0x1000 [lp855x_bl] do_one_initcall+0x58/0x1a0 do_init_module+0x54/0x1d0 load_module+0x1d80/0x21c8 __do_sys_finit_module+0xe8/0x100 __arm64_sys_finit_module+0x18/0x20 el0_svc_common.constprop.3+0xb0/0x168 do_el0_svc+0x20/0x98 el0_sync_handler+0xf4/0x1b0 el0_sync+0x140/0x180 Fix this by ensuring that the regulators are disabled, if enabled, on probe failure. Finally, ensure that the vddio regulator is disabled in the driver remove handler. Signed-off-by: Jon Hunter Reviewed-by: Daniel Thompson Signed-off-by: Lee Jones Signed-off-by: Sasha Levin

backlight: lm3630a: Return 0 on success in update_status functions

2020-01-27T13:46:34+00:00

[ Upstream commit d3f48ec0954c6aac736ab21c34a35d7554409112 ] lm3630a_bank_a_update_status() and lm3630a_bank_b_update_status() both return the brightness value if the brightness was successfully updated. Writing to these attributes via sysfs would cause a 'Bad address' error to be returned. These functions should return 0 on success, so let's change it to correct that error. Fixes: 28e64a68a2ef ("backlight: lm3630: apply chip revision") Signed-off-by: Brian Masney Acked-by: Pavel Machek Acked-by: Daniel Thompson Signed-off-by: Lee Jones Signed-off-by: Sasha Levin

backlight: lm3639: Unconditionally call led_classdev_unregister

2019-11-24T07:23:24+00:00

[ Upstream commit 7cea645ae9c5a54aa7904fddb2cdf250acd63a6c ] Clang warns that the address of a pointer will always evaluated as true in a boolean context. drivers/video/backlight/lm3639_bl.c:403:14: warning: address of 'pchip->cdev_torch' will always evaluate to 'true' [-Wpointer-bool-conversion] if (&pchip->cdev_torch) ~~ ~~~~~~~^~~~~~~~~~ drivers/video/backlight/lm3639_bl.c:405:14: warning: address of 'pchip->cdev_flash' will always evaluate to 'true' [-Wpointer-bool-conversion] if (&pchip->cdev_flash) ~~ ~~~~~~~^~~~~~~~~~ 2 warnings generated. These statements have been present since 2012, introduced by commit 0f59858d5119 ("backlight: add new lm3639 backlight driver"). Given that they have been called unconditionally since then presumably without any issues, removing the always true if statements to fix the warnings without any real world changes. Link: https://github.com/ClangBuiltLinux/linux/issues/119 Signed-off-by: Nathan Chancellor Reviewed-by: Daniel Thompson Signed-off-by: Lee Jones Signed-off-by: Sasha Levin

backlight: pwm_bl: Use gpiod_get_value_cansleep() to get initial state

2019-04-05T20:31:37+00:00

[ Upstream commit cec2b18832e26bc866bef2be22eff4e25bbc4034 ] gpiod_get_value() gives out a warning if access to the underlying gpiochip requires sleeping, which is common for I2C based chips: WARNING: CPU: 0 PID: 77 at drivers/gpio/gpiolib.c:2500 gpiod_get_value+0xd0/0x100 Modules linked in: CPU: 0 PID: 77 Comm: kworker/0:2 Not tainted 4.14.0-rc3-00589-gf32897915d48-dirty #90 Hardware name: Allwinner sun4i/sun5i Families Workqueue: events deferred_probe_work_func [] (unwind_backtrace) from [] (show_stack+0x10/0x14) [] (show_stack) from [] (dump_stack+0x88/0x9c) [] (dump_stack) from [] (__warn+0xe8/0x100) [] (__warn) from [] (warn_slowpath_null+0x20/0x28) [] (warn_slowpath_null) from [] (gpiod_get_value+0xd0/0x100) [] (gpiod_get_value) from [] (pwm_backlight_probe+0x238/0x508) [] (pwm_backlight_probe) from [] (platform_drv_probe+0x50/0xac) [] (platform_drv_probe) from [] (driver_probe_device+0x238/0x2e8) [] (driver_probe_device) from [] (bus_for_each_drv+0x44/0x94) [] (bus_for_each_drv) from [] (__device_attach+0xb0/0x114) [] (__device_attach) from [] (bus_probe_device+0x84/0x8c) [] (bus_probe_device) from [] (deferred_probe_work_func+0x50/0x14c) [] (deferred_probe_work_func) from [] (process_one_work+0x1ec/0x414) [] (process_one_work) from [] (worker_thread+0x2b0/0x5a0) [] (worker_thread) from [] (kthread+0x14c/0x154) [] (kthread) from [] (ret_from_fork+0x14/0x24) This was missed in commit 0c9501f823a4 ("backlight: pwm_bl: Handle gpio that can sleep"). The code was then moved to a separate function in commit 7613c922315e ("backlight: pwm_bl: Move the checks for initial power state to a separate function"). The only usage of gpiod_get_value() is during the probe stage, which is safe to sleep in. Switch to gpiod_get_value_cansleep(). Fixes: 0c9501f823a4 ("backlight: pwm_bl: Handle gpio that can sleep") Signed-off-by: Chen-Yu Tsai Acked-by: Maxime Ripard Acked-by: Daniel Thompson Signed-off-by: Lee Jones Signed-off-by: Sasha Levin

pwm-backlight: Enable/disable the PWM before/after LCD enable toggle.

2019-03-27T05:13:55+00:00

commit 5fb5caee92ba35a4a3baa61d45a78eb057e2c031 upstream. Before this patch the enable signal was set before the PWM signal and vice-versa on power off. This sequence is wrong, at least, it is on the different panels datasheets that I checked, so I inverted the sequence to follow the specs. For reference the following panels have the mentioned sequence: - N133HSE-EA1 (Innolux) - N116BGE (Innolux) - N156BGE-L21 (Innolux) - B101EAN0 (Auo) - B101AW03 (Auo) - LTN101NT05 (Samsung) - CLAA101WA01A (Chunghwa) Signed-off-by: Enric Balletbo i Serra Acked-by: Daniel Thompson Acked-by: Jingoo Han Acked-by: Thierry Reding Signed-off-by: Lee Jones Signed-off-by: Arnd Bergmann Signed-off-by: Greg Kroah-Hartman

backlight: pwm_bl: Don't use GPIOF_* with gpiod_get_direction

2018-08-03T05:50:38+00:00

[ Upstream commit bb084c0f61d659f0e6d371b096e0e57998f191d6 ] The documentation was wrong, gpiod_get_direction() returns 0/1 instead of the GPIOF_* flags. The docs were fixed with commit 94fc73094abe47 ("gpio: correct docs about return value of gpiod_get_direction"). Now, fix this user (until a better, system-wide solution is in place). Signed-off-by: Wolfram Sang Acked-by: Daniel Thompson Reviewed-by: Simon Horman Signed-off-by: Lee Jones Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

backlight: tps65217_bl: Fix Device Tree node lookup

2018-07-03T09:25:00+00:00

commit 2b12dfa124dbadf391cb9a616aaa6b056823bf75 upstream. Fix child-node lookup during probe, which ended up searching the whole device tree depth-first starting at the parent rather than just matching on its children. This would only cause trouble if the child node is missing while there is an unrelated node named "backlight" elsewhere in the tree. Cc: stable # 3.7 Fixes: eebfdc17cc6c ("backlight: Add TPS65217 WLED driver") Signed-off-by: Johan Hovold Acked-by: Daniel Thompson Signed-off-by: Lee Jones Signed-off-by: Greg Kroah-Hartman