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: NArvind Yadav <arvind.yadav.cs@gmail.com>
Acked-by: NThierry Reding <thierry.reding@gmail.com>
Acked-by: NDaniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: NLee Jones <lee.jones@linaro.org>

Commit 7613c922 ("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: 7613c922 ("backlight: pwm_bl: Move the checks for initial power state to a separate function")
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: NPeter Ujfalusi <peter.ujfalusi@ti.com>
Acked-by: NPhilipp Zabel <p.zabel@pengutronix.de>
Acked-by: NDaniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: NDaniel Thompson <daniel.thompson@linaro.org>

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: NPeter Ujfalusi <peter.ujfalusi@ti.com>
Acked-by: NPhilipp Zabel <p.zabel@pengutronix.de>
Reviewed-by: NThierry Reding <treding@nvidia.com>
Signed-off-by: NLee Jones <lee.jones@linaro.org>

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: NPeter Ujfalusi <peter.ujfalusi@ti.com>
Reviewed-by: NPhilipp Zabel <p.zabel@pengutronix.de>
Reviewed-by: NThierry Reding <treding@nvidia.com>
Signed-off-by: NLee Jones <lee.jones@linaro.org>

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: NMaxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: NLee Jones <lee.jones@linaro.org>

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: NBoris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: NThierry Reding <thierry.reding@gmail.com>

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: NBoris Brezillon <boris.brezillon@free-electrons.com>
Acked-by: NLee Jones <lee.jones@linaro.org>
Signed-off-by: NThierry Reding <thierry.reding@gmail.com>

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: NVladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Signed-off-by: NLee Jones <lee.jones@linaro.org>

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: NRobert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: NPhilipp Zabel <p.zabel@pengutronix.de>
Acked-by: NThierry Reding <thierry.reding@gmail.com>
Tested-by: NRobert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: NLee Jones <lee.jones@linaro.org>

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: NPhilipp Zabel <p.zabel@pengutronix.de>
Reviewed-by: NChristian Gmeiner <christian.gmeiner@gmail.com>
Tested-by: NHeiko Stuebner <heiko@sntech.de>
Signed-off-by: NLee Jones <lee.jones@linaro.org>

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: NDmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Signed-off-by: NVladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Acked-by: NThierry Reding <thierry.reding@gmail.com>
Acked-by: NNicolas Ferre <nicolas.ferre@atmel.com>
Tested-by: NRobert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: NLee Jones <lee.jones@linaro.org>

Since 39b2bbe3 (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: NAxel Lin <axel.lin@ingics.com>
Signed-off-by: NLee Jones <lee.jones@linaro.org>

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: NBoris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: NNicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: NThierry Reding <thierry.reding@gmail.com>
Signed-off-by: NLee Jones <lee.jones@linaro.org>

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: NDmitry Eremin-Solenikov <dmitry_eremin@mentor.com>
Signed-off-by: NVladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Signed-off-by: NLee 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: NPeter Griffin <peter.griffin@linaro.org>
Signed-off-by: NLee Jones <lee.jones@linaro.org>

commit 257462db ("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: NLothar Waßmann <LW@KARO-electronics.de>
Acked-by: NThierry Reding <treding@nvidia.com>
Signed-off-by: NLee Jones <lee.jones@linaro.org>

Make use of the new devm_gpiod_get_optional() to simplify the probe
code.
Signed-off-by: NAlexandre Courbot <acourbot@nvidia.com>
Signed-off-by: NLee 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: NJingoo Han <jg1.han@samsung.com>
Signed-off-by: NAndrzej Hajda <a.hajda@samsung.com>
Signed-off-by: NLee Jones <lee.jones@linaro.org>

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: NAlexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: NThierry Reding <thierry.reding@gmail.com>

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: NAlexandre Courbot <acourbot@nvidia.com>
Signed-off-by: NThierry Reding <thierry.reding@gmail.com>

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: NStephen Warren <swarren@nvidia.com>
Signed-off-by: NThierry Reding <treding@nvidia.com>

No need to have a specific OOM message, since there is generic MM out of memory
message in place.
Signed-off-by: NFabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: NThierry Reding <thierry.reding@gmail.com>

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: NJingoo Han <jg1.han@samsung.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

I forgot to remove this during earlier cleanup patches and only checked
various builds for errors, not warnings.
Reported-by: Nkbuild test robot <fengguang.wu@intel.com>
Signed-off-by: NThierry Reding <thierry.reding@gmail.com>

Use SIMPLE_DEV_PM_OPS macro will initialize the member "freeze"
and "thaw" of pwm_backlight_pm_ops as below,
	.freeze = suspend_fn,
	.thaw = resume_fn,
then during the process of making hibernation snapshot, screen
will be blank at the moment of freezing, and then light at the
moment of thawing.
this is not the right user experience for suspending to disk.

so this patch drops freeze and thaw callback, make the LCD is
always lighting before the final shutdown.
Signed-off-by: NHuayi Li <huayi.li@csr.com>
Signed-off-by: NBarry Song <Baohua.Song@csr.com>
Signed-off-by: NThierry Reding <thierry.reding@gmail.com>

Split adjustment of the brightness (by changing the PWM duty cycle) from
the power on sequence. This fixes an issue where the brightness can no
longer be updated once the backlight has been enabled.
Reported-by: NMarc Dietrich <marvin24@gmx.de>
Signed-off-by: NThierry Reding <treding@nvidia.com>

Currently the driver assumes that the values specified in the
brightness-levels device tree property increase as they are parsed from
left to right.  But boards that invert the signal between the PWM output
and the backlight will need to specify decreasing brightness-levels.
This patch removes the assumption that the last element of the array is
the maximum value, and instead searches the array for the maximum value
and uses that in the duty cycle calculation.
Signed-off-by: NMike Dunn <mikedunn@newsguy.com>
Signed-off-by: NThierry Reding <treding@nvidia.com>

Backlights require a power supply to work properly. This commit adds a
regulator to power up and power down the backlight.
Signed-off-by: NThierry Reding <treding@nvidia.com>

Make use of the new enable_gpio field and allow it to be set from DT as
well. Now that all legacy users of platform data have been converted to
initialize this field to an invalid value, it is safe to use the field
from the driver.
Signed-off-by: NThierry Reding <treding@nvidia.com>

Follow up patches will add support for more complex means of powering
the backlight on and off such as using a regulator. To prevent calls to
the regulator API from becoming unbalanced, keep track of the enabled
state internally.
Signed-off-by: NThierry Reding <treding@nvidia.com>

In preparation for adding an optional regulator and enable GPIO to the
driver, split the power on and power off sequences into separate
functions to reduce code duplication at the multiple call sites.
Signed-off-by: NThierry Reding <treding@nvidia.com>

Add more blank lines to increase readability. While at it, remove a
trailing blank line at the end of the file.
Signed-off-by: NThierry Reding <treding@nvidia.com>

When the macro such as SIMPLE_DEV_PM_OPS is used, there is
no need to use '#ifdef CONFIG_PM' to prevent build error. Thus,
this patch removes unnecessary ifdefs.
Signed-off-by: NJingoo Han <jg1.han@samsung.com>
Cc: Thierry Reding <thierry.reding@avionic-design.de>
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>

Use the wrapper function for getting the driver data using
backlight_device instead of using dev_get_drvdata with &bd->dev, so we can
directly pass a struct backlight_device.
Signed-off-by: NJingoo Han <jg1.han@samsung.com>
Cc: Thierry Reding <thierry.reding@avionic-design.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Move the dft_brightness validity check from the DT parsing function to the
main probe. In this way we can validate it in case we are booting with or
without DT.
Signed-off-by: NPeter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>

According to include/linux/backlight.h, the fb_blank field is to be
removed and blank status should preferably be set by setting the
BL_CORE_FBBLANK bit of the state field. This patch ensures this
condition is also taken into account when updating the backlight state.
Signed-off-by: NAlexandre Courbot <acourbot@nvidia.com>
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>

Managed versions of the pwm_get() and pwm_put() functions were recently
added to the PWM framework. They can be used to simplify cleanup in the
error paths and the device removal callback.

Cc: Thierry Reding <thierry.reding@avionic-design.de>
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Acked-by: NJingoo Han <jg1.han@samsung.com>
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>

pwm_backlight_update_status calls the notify() and notify_after()
callbacks before and after applying the new PWM settings. However, if
brightness levels are used, the brightness value will be changed from
the index into the levels array to the PWM duty cycle length before
being passed to notify_after(), which results in inconsistent behavior.
Signed-off-by: NAlexandre Courbot <acourbot@nvidia.com>
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>

This commit adds very basic support for device tree probing. Currently,
only a PWM and a list of distinct brightness levels can be specified.
Enabling or disabling backlight power via GPIOs is not yet supported.
Reviewed-by: NShawn Guo <shawn.guo@linaro.org>
Reviewed-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>

The various devm_ functions allocate memory that is released when a driver
detaches.  This patch uses these functions for data that is allocated in
the probe function of a platform device and is only freed in the remove
function.
Signed-off-by: NJulia Lawall <Julia.Lawall@lip6.fr>
Cc: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>