Workqueue, 'set_brightness_work' is used for scheduling brightness control.
This workqueue is canceled when the LED class device is unregistered.
Currently, LED subsystem handles like below.

  cancel_work_sync(&led_cdev->set_brightness_work)
  led_set_brightness(led_cdev, LED_OFF)

However, this could be a problem.
Workqueue is going to be canceled but LED device needs to be off.
The worst case is null pointer access due to scheduling a workqueue.

LED module is loaded.
  LED driver private data is allocated by using devm_zalloc().

LED module is unloaded.
  led_classdev_unregister() is called.
    cancel_work_sync()
      led_set_brightness(led_cdev, LED_OFF)
        schedule_work() if LED driver uses brightness_set_blocking()
        In the meantime, driver private data will be freed.

        ..scheduling..

        brightness_set_blocking() callback is invoked.
          For the brightness control, LED driver tries to access private
          data but resource is removed!

To avoid this problem, LED subsystem should turn off the brightness first
and wait for completion.

  led_set_brightness(led_cdev, LED_OFF)
  flush_work(&led_cdev->set_brightness_work)

It guarantees that LED driver turns off the brightness prior to
resource management.

Cc: linux-leds@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NMilo Kim <milo.kim@ti.com>
Signed-off-by: NJacek Anaszewski <j.anaszewski@samsung.com>

Strobe state variable is declared as unsigned long, remove
the check for values less than zero then.
Signed-off-by: NJacek Anaszewski <j.anaszewski@samsung.com>
Reported-by: NDavid Binderman <dcb314@hotmail.com>

The refcount of device_node increases after of_node_get() is called.
So, a break out of the loop requires of_node_put().

This patch adds missing of_node_put() when loop breaks.
Signed-off-by: NIngi Kim <ingi2.kim@samsung.com>
Acked-by: NRob Herring <robh@kernel.org>
Signed-off-by: NJacek Anaszewski <j.anaszewski@samsung.com>

Some PWMs are disabled by default or the default pin setting
does not match the LED_OFF state (e.g., active-low leds).
Hence, the driver may end up reporting 0 brightness, but
the leds are actually on using full brightness, because
it never enforces its default configuration.
So enforce it by calling led_pwm_set() after successfully
registering the device.

Tested on a Phytec phyFLEX i.MX6Q board based on kernel
v3.19.5.
Signed-off-by: NMarkus Hofstaetter <markus.hofstaetter@ait.ac.at>
Tested-by: NMarkus Hofstaetter <markus.hofstaetter@ait.ac.at>
Signed-off-by: NJacek Anaszewski <j.anaszewski@samsung.com>

The header of this file fixes the license to GPL 2 only without the
option to use later version. So use the string "GPL v2" that is to be
used in this case.
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: NFabio Baltieri <fabio.baltieri@gmail.com>
Signed-off-by: NJacek Anaszewski <j.anaszewski@samsung.com>

The transient trigger duration is documented to be in msec units, but is
actually in jiffies units. Other time based triggers are in msec units
as well. Fix the timer setup to convert from msec.

This could break an existing userspace that worked around this problem,
but exposing jiffies to userspace is just wrong and would break anyway
if HZ is changed.
Signed-off-by: NRob Herring <robh@kernel.org>
Cc: Shuah Khan <shuahkhan@gmail.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: linux-leds@vger.kernel.org
Signed-off-by: NJacek Anaszewski <j.anaszewski@samsung.com>

Now the core implements the work queue, remove it from the drivers,
and switch to using brightness_set_blocking op.
Signed-off-by: NJacek Anaszewski <j.anaszewski@samsung.com>
Cc: Daniel Jeong <daniel.jeong@ti.com>
Cc: G.Shark Jeong <gshark.jeong@gmail.com>

Now the core implements the work queue, remove it from the drivers,
and switch to using brightness_set_blocking op.
Signed-off-by: NJacek Anaszewski <j.anaszewski@samsung.com>
Cc: Raphael Assenat <raph@8d.com>

Now the core implements the work queue, remove it from the drivers,
and switch to using brightness_set_blocking op.
Signed-off-by: NJacek Anaszewski <j.anaszewski@samsung.com>
Cc: Raphael Assenat <raph@8d.com>

Now the core implements the work queue, remove it from the drivers,
and switch to using brightness_set_blocking op.
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NJacek Anaszewski <j.anaszewski@samsung.com>
Acked-by: NAntonio Ospite <ao2@ao2.it>
Reviewed-by: NMark Brown <broonie@kernel.org>

Now the core implements the work queue, remove it from the drivers,
and switch to using brightness_set_blocking op.
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Acked-by: NAntonio Ospite <ao2@ao2.it>
Signed-off-by: NJacek Anaszewski <j.anaszewski@samsung.com>

Now the core implements the work queue, remove it from the drivers,
and switch to using brightness_set_blocking op.
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NJacek Anaszewski <j.anaszewski@samsung.com>

Work queues are not used in this driver, so remove the include.
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>

Now the core implements the work queue, remove it from the drivers,
and switch to using brightness_set_blocking op.
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Cc: Daniel Mack <daniel@caiaq.de>
Signed-off-by: NJacek Anaszewski <j.anaszewski@samsung.com>

Now the core implements the work queue, remove it from the drivers,
and switch to using brightness_set_blocking op.
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Cc: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: NJacek Anaszewski <j.anaszewski@samsung.com>

Now the core implements the work queue, remove it from the drivers,
and switch to using brightness_set_blocking op.
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NJacek Anaszewski <j.anaszewski@samsung.com>

Now the core implements the work queue, remove it from the drivers,
and switch to using brightness_set_blocking op.
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NJacek Anaszewski <j.anaszewski@samsung.com>

Now the core implements the work queue, remove it from the drivers,
and switch to using brightness_set_blocking op.
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Reviewed-by: NMark Brown <broonie@kernel.org>
Signed-off-by: NJacek Anaszewski <j.anaszewski@samsung.com>

Now the core implements the work queue, remove it from the drivers,
and switch to using brightness_set_blocking op.
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NJacek Anaszewski <j.anaszewski@samsung.com>
Acked-by: NDan Murphy <dmurphy@ti.com>
Cc: Ricardo Ribalda <ricardo.ribalda@gmail.com>

Now the core implements the work queue, remove it from the drivers,
and switch to using brightness_set_blocking op.
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Cc: Nate Case <ncase@xes-inc.com>
Signed-off-by: NJacek Anaszewski <j.anaszewski@samsung.com>

Now the core implements the work queue, remove it from the drivers,
and switch to using brightness_set_blocking op.
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Acked-by: NDan Murphy <dmurphy@ti.com>
Signed-off-by: NJacek Anaszewski <j.anaszewski@samsung.com>

Now the core implements the work queue, remove it from the drivers,
and switch to using brightness_set_blocking op.
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Cc: Milo Kim <milo.kim@ti.com>
Signed-off-by: NJacek Anaszewski <j.anaszewski@samsung.com>

Now the core implements the work queue, remove it from the drivers,
and switch to using brightness_set_blocking op.
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NJacek Anaszewski <j.anaszewski@samsung.com>
Cc: Milo Kim <milo.kim@ti.com>

Now the core implements the work queue, remove it from the driver,
and switch to using brightness_set_blocking op.
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Acked-by: NAntonio Ospite <ao2@ao2.it>
Signed-off-by: NJacek Anaszewski <j.anaszewski@samsung.com>

Now the core implements the work queue, remove it from the driver,
and switch to using brightness_set_blocking op.
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NJacek Anaszewski <j.anaszewski@samsung.com>

Now the core implements the work queue, remove it from the driver,
and switch to using brightness_set_blocking op.
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Cc: Daniel Jeong <daniel.jeong@ti.com>
Cc: G.Shark Jeong <gshark.jeong@gmail.com>
Signed-off-by: NJacek Anaszewski <j.anaszewski@samsung.com>

Now the core implements the work queue, remove it from the driver,
and switch to using brightness_set_blocking op.
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NJacek Anaszewski <j.anaszewski@samsung.com>
Cc: Johan Hovold <johan@kernel.org>

Now the core implements the work queue, remove it from the driver,
and switch to using brightness_set_blocking op.
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Cc: Jan-Simon Moeller <dl9pf@gmx.de>
Signed-off-by: NJacek Anaszewski <j.anaszewski@samsung.com>

Now the core implements the work queue, remove it from the driver,
and switch to using brightness_set_blocking op.
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Cc: Kim Kyuwon <q1.kim@samsung.com>
Signed-off-by: NJacek Anaszewski <j.anaszewski@samsung.com>

Now the core implements the work queue, remove it from the driver,
and switch to using brightness_set_blocking op.
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Cc: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: NJacek Anaszewski <j.anaszewski@samsung.com>

Now the core implements the work queue, remove it from the driver,
and switch to using brightness_set_blocking op.
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NJacek Anaszewski <j.anaszewski@samsung.com>

Now the core implements the work queue, remove it from the driver,
and switch to using brightness_set_blocking op.
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NJacek Anaszewski <j.anaszewski@samsung.com>

LED subsystem shifted responsibility for choosing between SYNC or ASYNC
way of setting brightness from drivers to the caller. Adapt the wrapper
to those changes.
Signed-off-by: NJacek Anaszewski <j.anaszewski@samsung.com>
Cc: linux-media@vger.kernel.org
Acked-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Acked-by: NPavel Machek <pavel@ucw.cz>
Acked-by: NMauro Carvalho Chehab <mchehab@osg.samsung.com>

Now the core implements the work queue, remove it from the drivers,
and switch to using brightness_set_blocking op.
Signed-off-by: NJacek Anaszewski <j.anaszewski@samsung.com>
Cc: Ingi Kim <ingi2.kim@samsung.com>
Acked-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Acked-by: NPavel Machek <pavel@ucw.cz>

Now the core implements the work queue, remove it from the drivers,
and switch to using brightness_set_blocking op.
Signed-off-by: NJacek Anaszewski <j.anaszewski@samsung.com>
Acked-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Acked-by: NPavel Machek <pavel@ucw.cz>

Now the core implements the work queue, remove it from the drivers,
and switch to using brightness_set_blocking op.
Signed-off-by: NJacek Anaszewski <j.anaszewski@samsung.com>
Acked-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Acked-by: NPavel Machek <pavel@ucw.cz>

This patch adds description of the LED subsystem API for
setting an LED brightness.
Signed-off-by: NJacek Anaszewski <j.anaszewski@samsung.com>
Acked-by: NSakari Ailus <sakari.ailus@linux.intel.com>

This patch removes SET_BRIGHTNESS_ASYNC and SET_BRIGHTNESS_SYNC flags.
led_set_brightness() now calls led_set_brightness_nosleep() instead of
choosing between sync and async op basing on the flags defined by the
driver.

From now on, if a user wants to make sure that brightness will be set
synchronously, they have to use led_set_brightness_sync() API. It is now
being made publicly available since it has become apparent that it is
a caller who should decide whether brightness is to be set in
a synchronous or an asynchronous way.
Signed-off-by: NJacek Anaszewski <j.anaszewski@samsung.com>
Acked-by: NSakari Ailus <sakari.ailus@linux.intel.com>

This patch makes LED core capable of setting brightness for drivers
that implement brightness_set_blocking op. It removes from LED class
drivers responsibility for using work queues on their own.

In order to achieve this set_brightness_delayed callback is being
modified to directly call one of available ops for brightness setting.

led_set_brightness_async() function didn't set brightness in an
asynchronous way in all cases. It was mistakenly assuming that all
LED subsystem drivers used work queue in their brightness_set op,
whereas only half of them did that. Since it has no users now,
it is being removed.
Signed-off-by: NJacek Anaszewski <j.anaszewski@samsung.com>
Acked-by: NSakari Ailus <sakari.ailus@linux.intel.com>

This patch adds led_set_brightness_nosleep() and led_set_brightness_nopm()
functions, that guarantee setting LED brightness in a non-blocking way.
The latter is used from pm_ops context and doesn't modify the brightness
cached in the struct led_classdev. Its execution always ends up with
a call to brightness setting op - either directly or through
a set_brightness_work, regardless of LED_SUSPENDED flag state.

The patch also replaces led_set_brightness_async() with
led_set_brightness_nosleep() in all places where the most vital was setting
brightness in a non sleeping way but not necessarily asynchronously, which
is not needed for non-blocking drivers.
Signed-off-by: NJacek Anaszewski <j.anaszewski@samsung.com>
Acked-by: NSakari Ailus <sakari.ailus@linux.intel.com>