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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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
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With commit 88ba95bedb79 ("backlight: pwm_bl: Compute brightness of
LED linearly to human eye") the number of set bits (aka hweight())
in the PWM period is used in the heuristic to determine the number
of brightness levels, when the brightness table isn't specified in
the DT. The number of set bits doesn't provide a reliable clue about
the length of the period, instead change the heuristic to:
nlevels = period / fls(period)
Also limit the maximum number of brightness levels to 4096 to avoid
excessively large tables.
With this the number of levels increases monotonically with the PWM
period, until the maximum of 4096 levels is reached:
period (ns) # levels
100 16
500 62
1000 111
5000 416
10000 769
50000 3333
100000 4096
Fixes: 88ba95bedb79 ("backlight: pwm_bl: Compute brightness of LED linearly to human eye")
Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Tested-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
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Reduce size of duplicated comments by switching to use SPDX identifier.
No functional change.
While here, correct MODULE_LICENSE() string to be aligned with license text.
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>
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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>
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The integer exponentiation is used in few places and might be used in
the future by other call sites. Move it to wider use.
Link: http://lkml.kernel.org/r/20190323172531.80025-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Lee Jones <lee.jones@linaro.org>
Cc: Ray Jui <rjui@broadcom.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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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
[<c010ec50>] (unwind_backtrace) from [<c010b784>] (show_stack+0x10/0x14)
[<c010b784>] (show_stack) from [<c0797224>] (dump_stack+0x88/0x9c)
[<c0797224>] (dump_stack) from [<c0125b08>] (__warn+0xe8/0x100)
[<c0125b08>] (__warn) from [<c0125bd0>] (warn_slowpath_null+0x20/0x28)
[<c0125bd0>] (warn_slowpath_null) from [<c037069c>] (gpiod_get_value+0xd0/0x100)
[<c037069c>] (gpiod_get_value) from [<c03778d0>] (pwm_backlight_probe+0x238/0x508)
[<c03778d0>] (pwm_backlight_probe) from [<c0411a2c>] (platform_drv_probe+0x50/0xac)
[<c0411a2c>] (platform_drv_probe) from [<c0410224>] (driver_probe_device+0x238/0x2e8)
[<c0410224>] (driver_probe_device) from [<c040e820>] (bus_for_each_drv+0x44/0x94)
[<c040e820>] (bus_for_each_drv) from [<c040ff0c>] (__device_attach+0xb0/0x114)
[<c040ff0c>] (__device_attach) from [<c040f4f8>] (bus_probe_device+0x84/0x8c)
[<c040f4f8>] (bus_probe_device) from [<c040f944>] (deferred_probe_work_func+0x50/0x14c)
[<c040f944>] (deferred_probe_work_func) from [<c013be84>] (process_one_work+0x1ec/0x414)
[<c013be84>] (process_one_work) from [<c013ce5c>] (worker_thread+0x2b0/0x5a0)
[<c013ce5c>] (worker_thread) from [<c0141908>] (kthread+0x14c/0x154)
[<c0141908>] (kthread) from [<c0107ab0>] (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 <wens@csie.org>
Acked-by: Maxime Ripard <maxime.ripard@bootlin.com>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
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Pull backlight updates from Lee Jones:
"Fix-ups:
- Use new of_node_name_eq() API call
Bug Fixes:
- Internally track 'enabled' state in pwm_bl
- Fix auto-generated pwm_bl brightness tables parsed by DT
* tag 'backlight-next-4.21' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/backlight:
backlight: 88pm860x_bl: Use of_node_name_eq for node name comparisons
backlight: pwm_bl: Fix devicetree parsing with auto-generated brightness tables
backlight: pwm_bl: Re-add driver internal enabled tracking
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Commit '88ba95bedb79 ("backlight: pwm_bl: Compute brightness of LED
linearly to human eye")' allows the possibility to compute a default
brightness table when there isn't the brightness-levels property in the
DT. Unfortunately the changes made broke the pwm backlight for the
non-DT boards.
Usually, the non-DT boards don't pass the brightness levels via platform
data, instead, it sets the max_brightness in their platform data and the
driver calculates the level without a table. The offending patch assumed
that when there is no brightness levels table we should create one, but this
is clearly wrong for the non-DT case.
After this patch the code handles the DT and the non-DT case taking in
consideration also if max_brightness is set or not.
Fixes: 88ba95bedb79 ("backlight: pwm_bl: Compute brightness of LED linearly to human eye")
Reported-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Tested-by: Robert Jarzmik <robert.jarzmik@free.fr>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
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Commit 88ba95bedb79 ("backlight: pwm_bl: Compute brightness of LED linearly
to human eye") made the parse-dt function return early when using an auto-
generated brightness-table, but didn't take into account that some more
settings were handled below the brightness handling, like power-on-delays
and also setting the pdata enable-gpio to -EINVAL.
This surfaces for example in the case of a backlight without any
enable-gpio which then tries to use gpio-0 in error.
Fix this by simply moving the trailing settings above the brightness
handling.
Fixes: 88ba95bedb79 ("backlight: pwm_bl: Compute brightness of LED linearly to human eye")
Signed-off-by: Heiko Stuebner <heiko.stuebner@bq.com>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
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Commit e6bcca0890b9 ("backlight: pwm_bl: Switch to using "atomic" PWM API")
removed the driver internal enabled tracking in favor of simply checking
the pwm state.
This can lead to issues as all of gpio-, regulator- and pwm-state are used
to determine the initial state and the bootloader or kernel can leave them
in an inconsistent state at boot.
In my case on rk3399-kevin, the pwm backlight is build as module and the
kernel disables the supply regulator as unused while keeping the pwm running
thus pwm_bl calling pwm_backlight_power_off() during probe and creating an
unmatched regulator-disable call, as it never got enabled from the pwm-bl
before.
To prevent these consistency issues, reintroduce the driver-internal
tracking of the enabled state.
Fixes: e6bcca0890b9 ("backlight: pwm_bl: Switch to using "atomic" PWM API")
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Thierry Reding <thierry.reding@gmail.com>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
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The "atomic" API allows us to configure PWM period and duty_cycle and
enable it in one call.
The patch also moves the pwm_init_state just before any use of the
pwm_state struct, this fixes a potential bug where pwm_get_state
can be called before pwm_init_state.
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
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Currently, if the DT does not define num-interpolated-steps then
num_steps is undefined and the interpolation code will deploy randomly.
Fix with a simple initialize to zero.
Fixes: 573fe6d1c25c ("backlight: pwm_bl: Linear interpolation between brightness-levels")
Reported-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Tested-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
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When you want to change the brightness using a PWM signal, one thing you
need to consider is how human perceive the brightness. Human perceive
the brightness change non-linearly, we have better sensitivity at low
luminance than high luminance, so to achieve perceived linear dimming,
the brightness must be matches to the way our eyes behave. The CIE 1931
lightness formula is what actually describes how we perceive light.
This patch computes a default table with the brightness levels filled
with the numbers provided by the CIE 1931 algorithm, the number of the
brightness levels is calculated based on the PWM resolution.
The calculation of the table using the CIE 1931 algorithm is enabled by
default when you do not define the 'brightness-levels' propriety in your
device tree.
Signed-off-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>
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Setting num-interpolated-steps in the dts will allow you to have linear
interpolation between values of brightness-levels. This way a high
resolution pwm duty cycle can be used without having to list out every
possible value in the dts. This system also allows for gamma corrected
values.
The most simple example is interpolate between two brightness values a
number of steps, this can be done setting the following in the dts:
brightness-levels = <0 65535>;
num-interpolated-steps = <1024>;
default-brightness-level = <512>;
This will create a brightness-level table with the following values:
<0 63 126 189 252 315 378 441 ... 64260 64323 64386 64449 65535>
Another use case can be describe a gamma corrected curve, as we have
better sensitivity at low luminance than high luminance we probably
want have smaller steps for low brightness levels values and bigger
steps for high brightness levels values. This can be achieved with
the following in the dts:
brightness-levels = <0 4096 65535>;
num-interpolated-steps = <1024>;
default-brightness-level = <512>;
This will create a brightness-levels table with the following values:
<0 4 8 12 16 20 ... 4096 4156 4216 4276 ... 65535>
Signed-off-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>
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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 <wsa+renesas@sang-engineering.com>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
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Some panels (i.e. N116BGE-L41), in their power sequence specifications,
request a delay between set the PWM signal and enable the backlight and
between clear the PWM signal and disable the backlight. Add support for
the new post-pwm-on-delay-ms and pwm-off-delay-ms proprieties to meet
the timings.
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Acked-by: Jingoo Han <jingoohan1@gmail.com>
Acked-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
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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 <enric.balletbo@collabora.com>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Acked-by: Jingoo Han <jingoohan1@gmail.com>
Acked-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
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This fixes an overflow condition that can happen with high max
brightness and period values in compute_duty_cycle. This fixes it by
using a 64 bit variable for computing the duty cycle.
Signed-off-by: Derek Basehore <dbasehore@chromium.org>
Acked-by: Thierry Reding <thierry.reding@gmail.com>
Reviewed-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
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of_device_ids are not supposed to change at runtime. All functions
working with of_device_ids provided by <linux/of.h> work with const
of_device_ids. So mark the non-const structs as const.
Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Acked-by: Thierry Reding <thierry.reding@gmail.com>
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>
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Commit 7613c922315e308a ("backlight: pwm_bl: Move the checks for initial
power state to a separate function") not just moved some code, but made
slight changes in semantics.
If a gpiochip doesn't implement the optional .get_direction() callback,
gpiod_get_direction always returns -EINVAL, which is never equal to
GPIOF_DIR_IN, leading to the GPIO not being configured for output.
To avoid this, invert the test and check for not GPIOF_DIR_OUT instead,
like the original code did.
This restores the display on r8a7740/armadillo.
Fixes: 7613c922315e308a ("backlight: pwm_bl: Move the checks for initial power state to a separate function")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Acked-by: Philipp Zabel <p.zabel@pengutronix.de>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
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If the PWM is not enabled the backlight initially should not be enabled
either if we have booted with DT and there is a phandle pointing to the
backlight node.
The patch extends the checks to decide if we should keep the backlight off
initially.
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Acked-by: Philipp Zabel <p.zabel@pengutronix.de>
Reviewed-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
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Move the checks to select the initial state for the backlight to a new
function and document the checks we are doing.
With the separate function it is going to be easier to fix or improve the
initial power state configuration later and it is easier to read the code.
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Reviewed-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
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Some backlight GPIOs might be connected to some i2c based expanders whose
access might sleep.
Since it's not in any critical path, use the cansleep variant of the GPIO
API.
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
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The PWM framework has clarified the concept of reference PWM config (the
platform dependent config retrieved from the DT or the PWM lookup table)
and real PWM state.
Use pwm_get_args() when the PWM user wants to retrieve this reference
config and not the current state.
This is part of the rework allowing the PWM framework to support
hardware readout and expose real PWM state even when the PWM has just
been requested (before the user calls pwm_config/enable/disable()).
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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The PWM period will be set when calling pwm_config. Remove this useless
call to pwm_set_period(), which might mess up the internal PWM state.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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If pwm is requested by legacy pwm_request() and if the following
backlight_device_register() call fails, add pwm_free() clean-up.
Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
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Commit ee65ad0e2a9e ("backlight: pwm_bl: Avoid backlight flicker when
probed from DT") tries to dereference the device of_node pointer
unconditionally, causing a NULL pointer dereference on non-dt platforms.
Fix it by replacing the phandle variable with a node variable and
by checking that for NULL before dereferencing it.
Reported-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Acked-by: Thierry Reding <thierry.reding@gmail.com>
Tested-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
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If the driver is probed from the device tree, and there is a phandle
property set on it, and the enable GPIO is already configured as output,
and the backlight is currently disabled, keep it disabled.
If all these conditions are met, assume there will be some other driver
that can enable the backlight at the appropriate time.
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Reviewed-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
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Platform PWM backlight data provided by board's device tree should be
complete enough to successfully request a pwm device using pwm_get()
API. This change fixes a bug, when an arbitrary (first found) PWM is
connected to a "pwm-backlight" compatible device, when explicit PWM
device reference is not given.
Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt
already describes "pwms" as a required property, instead of blind
selection of a potentially wrong PWM reject legacy PWM device
registration request, leave legacy API only for non-dt cases.
Based on initial implementation done by Dmitry Eremin-Solenikov.
Reported-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Acked-by: Thierry Reding <thierry.reding@gmail.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Tested-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
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Pull backlight updates from Lee Jones:
"Changes to existing drivers:
- supply MODULE_DEVICE_TABLE() to ensure probing
- constify struct; da9052_bl
- enable compile test; lcd_l4f00242t03, lcd_lms283fg05, backlight_gpio
- suspend/resume bugfix; lp855x_bl
- devm_gpiod_get_optional() API fixup; pwm_bl
- error handling fixup; backlight"
* tag 'backlight-for-linus-4.2' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/backlight:
backlight: Change the return type of backlight_update_status() to int
backlight: pwm_bl: Simplify usage of devm_gpiod_get_optional
backlight: lp855x: Don't clear level on suspend/blank
backlight: Allow compile test of GPIO consumers if !GPIOLIB
video: backlight: da9052: Constify platform_device_id
gpio-backlight: Discover driver during boot time
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Since 39b2bbe3d715 (gpio: add flags argument to gpiod_get*() functions),
the gpiod_get* functions take an additional parameter that allows to
specify direction and initial value for output.
Simplify the usage of devm_gpiod_get_optional accordingly.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
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When trying to request the PWM device with devm_pwm_get(), the EPROBE_DEFER
flag is not handled properly. It can lead to the PWM not being found.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
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If PWM device is requested by means of legacy API pwm_request(), its
resources are not freed on module unbind, which may cause an oops on
access, e.g. by reading /sys/kernel/debug/pwm.
Reported-by: Dmitry Eremin-Solenikov <dmitry_eremin@mentor.com>
Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
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Pull backlight driver updates from Lee Jones:
"Changes to existing drivers:
- Checkpatch fixes
- Removal of unused code in generic_bl
- Removal of superfluous .owner attribute
No new or removed drivers/supported devices"
* tag 'backlight-for-linus-3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/backlight:
backlight: omap1: add blank line after declarations
backlight: jornada720: Remove 'else' after a return
backlight: jornada720: Remove 'else' after a return
backlight: wm831x_bl: Add blank line after declarations
backlight: tdo24m: Add blank line after declarations
backlight: s6e63m0: Remove 'else' after a return
backlight: pcf50633: Add blank line after declarations
backlight: lp855x: Add blank line after declarations
backlight: lms501kf03: Remove 'else' after a return
backlight: lm3639: Remove unnecessary return statements
backlight: ld9040: Remove 'else' after a return
backlight: ili922x: Remove 'else' after a return
backlight: cr_bllcd: Add blank line after declarations
backlight: corgi_lcd: Add blank line after declarations
backlight: ams369fg06: Remove 'else' after a return
backlight: adp8870: Add blank line after declarations
backlight: adp8860: Add blank line after declarations
backlight: adp5520: Add blank line after declarations
backlight: generic_bl: Remove unused function
backlight: Remove .owner field for drivers using module_platform_driver
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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>
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commit 257462dbf3ed ("pwm-backlight: switch to gpiod interface")
introduced a regression leading to acquiring a bogus GPIO-0 when
configured from DT without an 'enable-gpios' property.
The driver will happily accept the 0 initialized 'enable_gpio' member
of the struct platform_pwm_backlight_data as valid gpio number, and
request this GPIO as enable pin. In case of multiple driver instances,
the second will fail to register with the error message:
pwm-backlight backlight1.23: failed to request GPIO#0: -16
Fix this by setting enable_gpio in the pdata struct to -EINVAL.
Signed-off-by: Lothar Waßmann <LW@KARO-electronics.de>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
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Make use of the new devm_gpiod_get_optional() to simplify the probe
code.
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
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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>
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The PWM core is now able to initialize the PWM period from a lookup
table defined by board files. Use it if available and fallback to the
value supplied in pwm_period_ns.
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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Switch to the new gpiod interface, which allows to handle GPIO
properties such as active low transparently and removes a whole bunch of
code.
There are still a couple of users of this driver that rely on passing
the enable GPIO number through platform data, so a fallback mechanism
using a GPIO number is still available to avoid breaking them. It will
be removed once current users have switched to the GPIO lookup tables
provided by the gpiod interface.
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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When a device is shut down, make sure to disable the backlight. If it
stays lit, it gives the impression that the device hasn't turned off.
Furthermore keeping the backlight on may consume power, which is not
what users expect when they shut down a device.
Tested-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
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No need to have a specific OOM message, since there is generic MM out of memory
message in place.
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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Rasmus Villemoes
Matthias Kaehlcke
Linus Torvalds
Andy Shevchenko
Thomas Gleixner
Chen-Yu Tsai
Enric Balletbo i Serra
Heiko Stuebner
Heiko Stuebner
Daniel Thompson
Wolfram Sang
Derek Basehore
Arvind Yadav
Geert Uytterhoeven
Peter Ujfalusi
Maxime Ripard
Boris Brezillon
Vladimir Zapolskiy
Philipp Zabel
Axel Lin
Nicolas Ferre
Peter Griffin
Lothar Waßmann
Alexandre Courbot
Andrzej Hajda
Alexandre Belloni
Thierry Reding
Fabio Estevam