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path: root/drivers/video/backlight
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2020-07-06backlight: lms501kf03: Remove unused const variablesLee Jones
W=1 kernel build reports: drivers/video/backlight/lms501kf03.c:96:28: warning: ‘seq_sleep_in’ defined but not used [-Wunused-const-variable=] 96 | static const unsigned char seq_sleep_in[] = { | ^~~~~~~~~~~~ drivers/video/backlight/lms501kf03.c:92:28: warning: ‘seq_up_dn’ defined but not used [-Wunused-const-variable=] 92 | static const unsigned char seq_up_dn[] = { | ^~~~~~~~~ Either 'seq_sleep_in' nor 'seq_up_dn' have been used since the driver first landed in 2013. Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Signed-off-by: Lee Jones <lee.jones@linaro.org> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Reviewed-by: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Lee Jones <lee.jones@linaro.org>
2020-07-01backlight: lms501kf03: Drop unused includeLinus Walleij
This driver includes <linux/gpio.h> but does not use any symbols from that file, drop the include. Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Lee Jones <lee.jones@linaro.org>
2020-07-01backlight: Delete the OT200 backlight driverLinus Walleij
This driver has no in-kernel users. The device can only be populated by board files since it does not support device tree nor ACPI, and nothing in the kernel creates a device named "ot200-backlight". This driver has been in the kernel since 2012. If it is used by out-of-tree code that code should have been upstreamed by now, it's been 8 years. It uses the idiomatic forked GPIO of the CS5535 which combines pin control and GPIO into its private custom interface, which causes me a headache because that is not how we do things these days: we creates separate pin control and GPIO drivers. Delete this unused driver. Cc: Christian Gmeiner <christian.gmeiner@gmail.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Lee Jones <lee.jones@linaro.org>
2020-07-01backlight: sky81452: Privatize platform dataLinus Walleij
The only way the platform data for the SKY81452 ever gets populated is through the device tree. The MFD device is bothered with this for no reason at all. Just allocate the platform data in the driver and be happy. Cc: Gyungoh Yoo <jack.yoo@skyworksinc.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Lee Jones <lee.jones@linaro.org>
2020-07-01backlight: sky81452: Convert to GPIO descriptorsLinus Walleij
The SKY81452 backlight driver just obtains a GPIO (named "gpios" in the device tree) drives it high and leaves it high until the driver is removed. Switch to use GPIO descriptors for this, simple and straight-forward. Cc: Gyungoh Yoo <jack.yoo@skyworksinc.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Lee Jones <lee.jones@linaro.org>
2020-06-19video: backlight: tosa_lcd: convert to use i2c_new_client_device()Wolfram Sang
Move away from the deprecated API and return the shiny new ERRPTR where useful. Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Acked-by: Lee Jones <lee.jones@linaro.org> Signed-off-by: Wolfram Sang <wsa@kernel.org>
2020-06-17backlight: pwm_bl: Use 64-bit division functionGuru Das Srinagesh
Since the PWM framework is switching struct pwm_state.period's datatype to u64, prepare for this transition by using div_u64 to handle a 64-bit dividend instead of a straight division operation. Signed-off-by: Guru Das Srinagesh <gurus@codeaurora.org> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Acked-by: Lee Jones <lee.jones@linaro.org> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2020-06-16backlight: lm3533_bl: Use kobj_to_dev() insteadWang Qing
Use kobj_to_dev() instead of container_of() Signed-off-by: Wang Qing <wangqing@vivo.com> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Lee Jones <lee.jones@linaro.org>
2020-05-11backlight: Add backlight_device_get_by_name()Noralf Trønnes
Add a way to lookup a backlight device based on its name. Will be used by a USB display gadget getting the name from configfs. Signed-off-by: Noralf Trønnes <noralf@tronnes.org> Reviewed-by: Sam Ravnborg <sam@ravnborg.org> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Acked-by: Jingoo Han <jingoohan1@gmail.com> Signed-off-by: Lee Jones <lee.jones@linaro.org>
2020-05-06backlight: qcom-wled: Add support for WLED5 peripheral that is present on ↵Subbaraman Narayanamurthy
PM8150L PMICs PM8150L WLED supports the following: - Two modulators and each sink can use any of the modulator - Multiple CABC selection options from which one can be selected/enabled - Multiple brightness width selection (12 bits to 15 bits) Signed-off-by: Subbaraman Narayanamurthy <subbaram@codeaurora.org> Signed-off-by: Kiran Gunda <kgunda@codeaurora.org> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Lee Jones <lee.jones@linaro.org>
2020-05-06backlight: qcom-wled: Add callback functionsKiran Gunda
Add wled_cabc_config, wled_sync_toggle, wled_ovp_fault_status and wled_ovp_delay and wled_auto_detection_required callback functions to prepare the driver for adding WLED5 support. Signed-off-by: Kiran Gunda <kgunda@codeaurora.org> Signed-off-by: Subbaraman Narayanamurthy <subbaram@codeaurora.org> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Lee Jones <lee.jones@linaro.org>
2020-04-29backlight: l4f00242t03: Convert to GPIO descriptorsLinus Walleij
This converts the l4f00242t03 backlight driver to use GPIO descriptors and switches the two Freescale i.MX boards over to passing descriptors instead of global GPIO numbers. We use the typical names "enable" and "reset" as found in the device tree bindings for panel GPIOs. This saves a lot of code in the driver and makes it possible to get rid of the platform data header altogether. Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Acked-by: Shawn Guo <shawnguo@kernel.org> Signed-off-by: Lee Jones <lee.jones@linaro.org>
2020-04-28backlight: lp855x: Ensure regulators are disabled on probe failureJon Hunter
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 <jonathanh@nvidia.com> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Lee Jones <lee.jones@linaro.org>
2020-04-07Merge tag 'backlight-next-5.7' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/lee/backlight Pull backlight updates from Lee Jones: "Switch pwm_bl and corgi_lcd drivers to use GPIO descriptors" * tag 'backlight-next-5.7' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/backlight: backlight: corgi: Convert to use GPIO descriptors backlight: pwm_bl: Switch to full GPIO descriptor
2020-03-25backlight: corgi: Convert to use GPIO descriptorsLinus Walleij
The code in the Corgi backlight driver can be considerably simplified by moving to GPIO descriptors and lookup tables from the board files instead of passing GPIO numbers using the old API. Make sure to encode inversion semantics for the Akita and Spitz platforms inside the GPIO lookup table and drop the custom inversion semantics from the driver. All in-tree users are converted in this patch. Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Acked-by: Robert Jarzmik <robert.jarzmik@free.fr> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Lee Jones <lee.jones@linaro.org>
2020-03-18backlight: pwm_bl: Switch to full GPIO descriptorLinus Walleij
The PWM backlight still supports passing a enable GPIO line as platform data using the legacy <linux/gpio.h> API. It turns out that ever board using this mechanism except one is pass .enable_gpio = -1. So we drop all these cargo-culted -1's from all instances of this platform data in the kernel. The remaning board, Palm TC, is converted to pass a machine descriptior table with the "enable" GPIO instead, and delete the platform data entry for enable_gpio and the code handling it and things should work smoothly with the new API. Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Acked-by: Robert Jarzmik <robert.jarzmik@free.fr> Acked-by: Krzysztof Kozlowski <krzk@kernel.org Reviewed-by: Bartosz Golaszewski <bgolaszewski@baylibre.com> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Lee Jones <lee.jones@linaro.org>
2020-03-11Merge v5.6-rc5 into drm-nextDave Airlie
Requested my mripard for some misc patches that need this as a base. Signed-off-by: Dave Airlie <airlied@redhat.com>
2020-02-21Merge tag 'drm-misc-next-2020-02-10' of ↵Dave Airlie
git://anongit.freedesktop.org/drm/drm-misc into drm-next drm-misc-next for 5.7: UAPI Changes: - lima: Add support for heap buffers Cross-subsystem Changes: Core Changes: - Implement mode_config mode_valid for memory constrained drivers - Bus format negociation between bridges - Consolidate fake vblank events for drivers without vblank interrupts - drm/bufs: dma_alloc related cleanups - drm/dp_mst: Various fixes - drm/print: New drm_device based print helpers - Thomas is a drm-misc maintainer now! Driver Changes: - DPMS cleanups for atomic drivers - Removal of owner field in SPI tinydrm drivers - Removal of explicit dependency on DT for tinydrm drivers - Conversion to YAML schemas for DT bindings - tidss: New driver - virtio: various reworks and fixes - Our usual dozen or so new panels or bridges Signed-off-by: Dave Airlie <airlied@redhat.com> From: Maxime Ripard <maxime@cerno.tech> Link: https://patchwork.freedesktop.org/patch/msgid/20200210093421.xu4sofldm6wm6xq6@gilmour.lan
2020-02-19backlight: add led-backlight driverTomi Valkeinen
This patch adds a led-backlight driver (led_bl), which is similar to pwm_bl except the driver uses a LED class driver to adjust the brightness in the HW. Multiple LEDs can be used for a single backlight. Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com> Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com> Acked-by: Pavel Machek <pavel@ucw.cz> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Acked-by: Lee Jones <lee.jones@linaro.org> Acked-by: Tony Lindgren <tony@atomide.com> Tested-by: Tony Lindgren <tony@atomide.com> Tested-by: Guido Günther <agx@sigxcpu.org> Signed-off-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Tony Lindgren <tony@atomide.com>
2020-01-23backlight: qcom-wled: Fix unsigned comparison to zeroChen Zhou
Fixes coccicheck warning: ./drivers/video/backlight/qcom-wled.c:1104:5-15: WARNING: Unsigned expression compared with zero: string_len > 0 The unsigned variable string_len is assigned a return value from the call to of_property_count_elems_of_size(), which may return negative error code. Fixes: 775d2ffb4af6 ("backlight: qcom-wled: Restructure the driver for WLED3") Signed-off-by: Chen Zhou <chenzhou10@huawei.com> Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Reviewed-by: Kiran Gunda <kgunda@codeaurora.org> Signed-off-by: Lee Jones <lee.jones@linaro.org>
2020-01-15video: Fix Kconfig indentationKrzysztof Kozlowski
Adjust indentation from spaces to tab (+optional two spaces) as in coding style with command like: $ sed -e 's/^ /\t/' -i */Kconfig Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org> Cc: Jiri Kosina <trivial@kernel.org> Cc: Lee Jones <lee.jones@linaro.org> Cc: Daniel Thompson <daniel.thompson@linaro.org> Cc: Jingoo Han <jingoohan1@gmail.com> Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Link: https://patchwork.freedesktop.org/patch/msgid/20191120133838.13132-1-krzk@kernel.org
2019-12-16backlight: bd6107: Convert to use GPIO descriptorLinus Walleij
The Rohm BD6107 driver can pass a fixed GPIO line using the old GPIO API using platform data. As there are no in-tree users of this platform data since 2013, we can convert this to use a GPIO descriptor and require any out-of-tree consumers to pass the GPIO using a machine descriptor table instead. Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Lee Jones <lee.jones@linaro.org>
2019-12-16backlight: ams369fg06: Drop GPIO includeLinus Walleij
The driver includes <linux/gpio.h> yet fails to use symbols from any the header so drop the include. Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Lee Jones <lee.jones@linaro.org>
2019-11-13backlight: qcom-wled: Fix spelling mistake "trigged" -> "triggered"Colin Ian King
There is a spelling mistake in a dev_err error message. Fix it. Signed-off-by: Colin Ian King <colin.king@canonical.com> 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>
2019-11-11video: backlight: tosa: Use GPIO lookup tableArnd Bergmann
The driver should not require a machine specific header. Change it to pass the GPIO line through a lookup table, and move the timing generator definitions into the drivers itself. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Robert Jarzmik <robert.jarzmik@free.fr> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Lee Jones <lee.jones@linaro.org>
2019-11-01backlight: qcom-wled: Add auto string detection logicKiran Gunda
The auto string detection algorithm checks if the current WLED sink configuration is valid. It tries enabling every sink and checks if the OVP fault is observed. Based on this information it detects and enables the valid sink configuration. Auto calibration will be triggered when the OVP fault interrupts are seen frequently thereby it tries to fix the sink configuration. The auto-detection also kicks in when the connected LED string of the display-backlight malfunctions (because of damage) and requires the damaged string to be turned off to prevent the complete panel and/or board from being damaged. Signed-off-by: Kiran Gunda <kgunda@codeaurora.org> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Lee Jones <lee.jones@linaro.org>
2019-11-01backlight: qcom-wled: Add support for short circuit handlingKiran Gunda
Handle the short circuit interrupt and check if the short circuit interrupt is valid. Re-enable the module to check if it goes away. Disable the module altogether if the short circuit event persists. Signed-off-by: Kiran Gunda <kgunda@codeaurora.org> Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Lee Jones <lee.jones@linaro.org>
2019-11-01backlight: qcom-wled: Add support for WLED4 peripheralKiran Gunda
WLED4 peripheral is present on some PMICs like pmi8998 and pm660l. It has a different register map and configurations are also different. Add support for it. Signed-off-by: Kiran Gunda <kgunda@codeaurora.org> Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Lee Jones <lee.jones@linaro.org>
2019-11-01backlight: qcom-wled: Restructure the driver for WLED3Kiran Gunda
Restructure the driver to add the support for new WLED peripherals. Signed-off-by: Kiran Gunda <kgunda@codeaurora.org> Acked-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Lee Jones <lee.jones@linaro.org>
2019-11-01backlight: qcom-wled: Rename PM8941* to WLED3Kiran Gunda
Rename the PM8941* references as WLED3 to make the driver generic and have WLED support for other PMICs. Also rename "i_boost_limit" and "i_limit" variables to "boost_i_limit" and "string_i_limit" respectively to resemble the corresponding register names. Signed-off-by: Kiran Gunda <kgunda@codeaurora.org> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Lee Jones <lee.jones@linaro.org>
2019-11-01backlight: qcom-wled: Rename pm8941-wled.c to qcom-wled.cKiran Gunda
pm8941-wled.c driver is supporting the WLED peripheral on pm8941. Rename it to qcom-wled.c so that it can support WLED on multiple PMICs. Signed-off-by: Kiran Gunda <kgunda@codeaurora.org> Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org> Acked-by: Rob Herring <robh@kernel.org> Acked-by: Daniel Thompson <daniel.thompson@linaro.org> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Lee Jones <lee.jones@linaro.org>
2019-10-18backlight: Kconfig: jornada720: Use CONFIG_PREEMPTIONThomas Gleixner
CONFIG_PREEMPTION is selected by CONFIG_PREEMPT and by CONFIG_PREEMPT_RT. Both PREEMPT and PREEMPT_RT require the same functionality which today depends on CONFIG_PREEMPT. Switch the Kconfig dependency to CONFIG_PREEMPTION. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> [Sebastian: +LCD_HP700] Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Lee Jones <lee.jones@linaro.org>
2019-10-14backlight: pwm_bl: Switch to power-of-2 base for fixed-point mathRasmus Villemoes
Using a power-of-2 instead of power-of-10 base makes the computations much cheaper. 2^16 is safe; retval never becomes more than 2^48 + 2^32/2. On a 32 bit platform, the very expensive 64/32 division at the end of cie1931() instead becomes essentially free (a shift by 32 is just a register rename). Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Lee Jones <lee.jones@linaro.org>
2019-10-14backlight: pwm_bl: Drop use of int_pow()Rasmus Villemoes
For a fixed small exponent of 3, it is more efficient to simply use two explicit multiplications rather than calling the int_pow() library function: Aside from the function call overhead, its implementation using repeated squaring means it ends up doing four 64x64 multiplications. Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Lee Jones <lee.jones@linaro.org>
2019-10-14backlight: pwm_bl: Eliminate a 64/32 divisionRasmus Villemoes
lightness*1000 is nowhere near overflowing 32 bits, so we can just use an ordinary 32/32 division, which is much cheaper than the 64/32 done via do_div(). Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Lee Jones <lee.jones@linaro.org>
2019-10-14backlight: pwm_bl: Fix cie1913 comments and constantRasmus Villemoes
The "break-even" point for the two formulas is L==8, which is also what the code actually implements. [Incidentally, at that point one has Y=0.008856, not 0.08856]. Moreover, all the sources I can find say the linear factor is 903.3 rather than 902.3, which makes sense since then the formulas agree at L==8, both yielding the 0.008856 figure to four significant digits. Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Lee Jones <lee.jones@linaro.org>
2019-10-14backlight: pwm_bl: Add missing curly branches in else branchMatthias Kaehlcke
Add curly braces to an 'else' branch in pwm_backlight_update_status() to match the corresponding 'if' branch. Signed-off-by: Matthias Kaehlcke <mka@chromium.org> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Lee Jones <lee.jones@linaro.org>
2019-10-14backlight: pwm_bl: Don't assign levels table repeatedlyMatthias Kaehlcke
pwm_backlight_probe() re-assigns pb->levels for every brightness level. This is not needed and was likely not intended, since neither side of the assignment changes during the loop. Assign the field only once. Signed-off-by: Matthias Kaehlcke <mka@chromium.org> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Lee Jones <lee.jones@linaro.org>
2019-10-02backlight: lm3630a: Add an enable gpio for the HWEN pinAndreas Kemnade
For now just enable it in the probe function to allow I2C access. Disabling also means resetting the register values to default and according to the datasheet does not give power savings. Tested on Kobo Clara HD. Signed-off-by: Andreas Kemnade <andreas@kemnade.info> Reviewed-by: Dan Murphy <dmurphy@ti.com> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Lee Jones <lee.jones@linaro.org>
2019-10-02backlight: ipaq_micro: Make structure micro_bl_props constantNishka Dasgupta
Static structure micro_bl_props, having type backlight_properties, is used only once, when it is passed as the last argument to function devm_backlight_device_register(). devm_backlight_device_register() is defined with its last parameter being declared constant. Hence make micro_bl_props itself constant as well. Issue found with Coccinelle. Signed-off-by: Nishka Dasgupta <nishkadg.linux@gmail.com> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Lee Jones <lee.jones@linaro.org>
2019-10-02backlight: lm3630a: Fix module aliasesAndreas Kemnade
Devicetree aliases are missing, so that module autoloading does not work properly. Signed-off-by: Andreas Kemnade <andreas@kemnade.info> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Lee Jones <lee.jones@linaro.org>
2019-09-23Merge tag 'backlight-next-5.4' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/lee/backlight Pull backlight updates from Lee Jones: "Core Frameworks - Obtain scale type through sysfs New Functionality: - Provide Device Tree functionality in rave-sp-backlight - Calculate if scale type is (non-)linear in pwm_bl Fix-ups: - Simplify code in lm3630a_bl - Trivial rename/whitespace/typo fixes in lms283gf05 - Remove superfluous NULL check in tosa_lcd - Fix power state initialisation in gpio_backlight - List supported file in MAINTAINERS Bug Fixes: - Kconfig - default to not building unless requested in {LED,BACKLIGHT}_CLASS_DEVICE" * tag 'backlight-next-5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/backlight: backlight: pwm_bl: Set scale type for brightness curves specified in the DT backlight: pwm_bl: Set scale type for CIE 1931 curves backlight: Expose brightness curve type through sysfs MAINTAINERS: Add entry for stable backlight sysfs ABI documentation backlight: gpio-backlight: Correct initial power state handling video: backlight: tosa_lcd: drop check because i2c_unregister_device() is NULL safe video: backlight: Drop default m for {LCD,BACKLIGHT_CLASS_DEVICE} backlight: lms283gf05: Fix a typo in the description passed to 'devm_gpio_request_one()' backlight: lm3630a: Switch to use fwnode_property_count_uXX() backlight: rave-sp: Leave initial state and register with correct device
2019-09-02backlight: pwm_bl: Set scale type for brightness curves specified in the DTMatthias Kaehlcke
Check if a brightness curve specified in the device tree is linear or not and set the corresponding property accordingly. This makes the scale type available to userspace via the 'scale' sysfs attribute. To determine if a curve is linear it is compared to a interpolated linear curve between min and max brightness. The curve is considered linear if no value deviates more than +/-5% of ${brightness_range} from their interpolated value. Signed-off-by: Matthias Kaehlcke <mka@chromium.org> Acked-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Lee Jones <lee.jones@linaro.org>
2019-09-02backlight: pwm_bl: Set scale type for CIE 1931 curvesMatthias Kaehlcke
For backlight curves calculated with the CIE 1931 algorithm set the brightness scale type to non-linear. This makes the scale type available to userspace via the 'scale' sysfs attribute. Signed-off-by: Matthias Kaehlcke <mka@chromium.org> Tested-by: Enric Balletbo i Serra <enric.balletbo@collabora.com> Acked-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Lee Jones <lee.jones@linaro.org>