linux-toradex.git/drivers/leds/led-class.c, branch v4.10 Linux kernel for Apalis and Colibri modules led: core: Use atomic bit-field for the blink-flags 2016-11-22T11:07:05+00:00 Hans de Goede hdegoede@redhat.com 2016-11-08T13:38:46+00:00 a9c6ce57ec2f136d08141e8220a0ffaca216f7b0 All the LED_BLINK* flags are accessed read-modify-write from e.g. led_set_brightness and led_blink_set_oneshot while both set_brightness_work and the blink_timer may be running. If these race then the modify step done by one of them may be lost, switch the LED_BLINK* flags to a new atomic work_flags bit-field to avoid this race. Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com> 
All the LED_BLINK* flags are accessed read-modify-write from e.g.
led_set_brightness and led_blink_set_oneshot while both
set_brightness_work and the blink_timer may be running.

If these race then the modify step done by one of them may be lost,
switch the LED_BLINK* flags to a new atomic work_flags bit-field
to avoid this race.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com>
leds: Use macro for max device node name size 2016-11-22T11:07:02+00:00 David Lechner david@lechnology.com 2016-09-16T19:16:49+00:00 eb1ce7469940b4eb8a466d9ae4d032fb2c9969dc Use a macro instead of hard-coding the max device node name size. The uleds driver introduced a macro for this value, so using it. Signed-off-by: David Lechner <david@lechnology.com> Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com> 
Use a macro instead of hard-coding the max device node name size. The
uleds driver introduced a macro for this value, so using it.

Signed-off-by: David Lechner <david@lechnology.com>
Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com>
leds: core: avoid error message when a USB LED device is unplugged 2016-03-14T08:22:20+00:00 Heiner Kallweit hkallweit1@gmail.com 2016-01-22T20:43:48+00:00 d84d80f38f0ff4eb4becf1a3569c8e7b2c463b61 When a USB LED device is unplugged the remove call chain calls led_classdev_unregister which tries to switch the LED off. As the device has been removed already this results in a ENODEV error message in dmesg. Avoid this error message by ignoring ENODEV in calls from led_classdev_unregister if the LED device is flagged as pluggable. Therefore a new flag LED_HW_PLUGGABLE was introduced which should be set by all LED drivers handling pluggable LED devices (mainly USB LED devices). Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com> Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com> 
When a USB LED device is unplugged the remove call chain calls
led_classdev_unregister which tries to switch the LED off.
As the device has been removed already this results in a ENODEV
error message in dmesg.
Avoid this error message by ignoring ENODEV in calls from
led_classdev_unregister if the LED device is flagged as pluggable.

Therefore a new flag LED_HW_PLUGGABLE was introduced which should be set by
all LED drivers handling pluggable LED devices (mainly USB LED devices).

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com>
leds: turn off the LED and wait for completion on unregistering LED class device 2016-01-04T08:57:37+00:00 Milo Kim milo.kim@ti.com 2015-11-20T08:03:00+00:00 d1aa577f5e191d77d3ad62da93729b5af9532bb4 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: Milo Kim <milo.kim@ti.com> Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com> 
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: Milo Kim <milo.kim@ti.com>
Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com>
leds: core: Drivers shouldn't enforce SYNC/ASYNC brightness setting 2016-01-04T08:57:31+00:00 Jacek Anaszewski j.anaszewski@samsung.com 2015-10-07T09:10:43+00:00 13ae79bbe4c214047f51623304d83b46eb02897d 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: Jacek Anaszewski <j.anaszewski@samsung.com> Acked-by: Sakari 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: Jacek Anaszewski <j.anaszewski@samsung.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
leds: core: Add led_set_brightness_nosleep{nopm} functions 2016-01-04T08:57:30+00:00 Jacek Anaszewski j.anaszewski@samsung.com 2015-10-07T09:10:41+00:00 81fe8e5b73e3f4de578ac7f53c1d956d4f58b8d4 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: Jacek Anaszewski <j.anaszewski@samsung.com> Acked-by: Sakari 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: Jacek Anaszewski <j.anaszewski@samsung.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
leds: core: Move LED core callbacks out of led-class.c 2015-11-03T07:59:22+00:00 Jacek Anaszewski j.anaszewski@samsung.com 2015-09-28T12:38:04+00:00 757b06ae04b3b6c8958ab067e879a8865d076d2a Since the API for controlling LED brightness and blinking is defined in the LED core, move the related timer and work callbacks to the led-core.c, and initialize them through a new led_core_init API. Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com> Acked-by: Andrew Lunn <andrew@lunn.ch> Acked-by: Pavel Machek <pavel@ucw.cz> 
Since the API for controlling LED brightness and blinking is defined in
the LED core, move the related timer and work callbacks to the led-core.c,
and initialize them through a new led_core_init API.

Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com>
Acked-by: Andrew Lunn <andrew@lunn.ch>
Acked-by: Pavel Machek <pavel@ucw.cz>
leds/led-class: Add missing put_device() 2015-08-28T12:06:19+00:00 Ricardo Ribalda Delgado ricardo.ribalda@gmail.com 2015-07-31T11:36:21+00:00 e5b5a61fcb3743f1dacf9e20d28f48423cecf0c1 Devices found by class_find_device must be freed with put_device(). Otherwise the reference count will not work properly. Fixes: a96aa64cb572 ("leds/led-class: Handle LEDs with the same name") Reported-by: Alan Tull <delicious.quinoa@gmail.com> Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com> Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com> 
Devices found by class_find_device must be freed with put_device().
Otherwise the reference count will not work properly.

Fixes: a96aa64cb572 ("leds/led-class: Handle LEDs with the same name")
Reported-by: Alan Tull <delicious.quinoa@gmail.com>
Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com>
Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/cooloney/linux-leds 2015-07-02T02:09:11+00:00 Linus Torvalds torvalds@linux-foundation.org 2015-07-02T02:09:11+00:00 13d45f79a2af84de9083310db58b309a61065208 Pull LED subsystem updates from Bryan Wu: "In this cycle, we finished to merge patches for LED Flash class driver. Other than that we have some bug fixes and new drivers for LED controllers" * 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/cooloney/linux-leds: (33 commits) leds:lp55xx: fix firmware loading error leds: fix max77693-led build errors leds: fix aat1290 build errors leds: aat1290: pass flags parameter to devm_gpiod_get leds: ktd2692: pass flags parameter to devm_gpiod_get drivers/leds: don't use module_init in non-modular leds-cobalt-raq.c leds: aat1290: add support for V4L2 Flash sub-device DT: aat1290: Document handling external strobe sources leds: max77693: add support for V4L2 Flash sub-device media: Add registration helpers for V4L2 flash sub-devices v4l: async: Add a pointer to of_node to struct v4l2_subdev, match it Documentation: leds: Add description of v4l2-flash sub-device leds: add BCM6358 LED driver leds: add DT binding for BCM6358 LED controller leds: fix brightness changing when software blinking is active Documentation: leds-lp5523: describe master fader attributes leds: lp5523: add master_fader support leds: leds-gpio: Allow compile test if !GPIOLIB leds: leds-gpio: Add missing #include <linux/of.h> gpiolib: Add missing dummies for the unified device properties interface ... 
Pull LED subsystem updates from Bryan Wu:
 "In this cycle, we finished to merge patches for LED Flash class
  driver.

  Other than that we have some bug fixes and new drivers for LED
  controllers"

* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/cooloney/linux-leds: (33 commits)
  leds:lp55xx: fix firmware loading error
  leds: fix max77693-led build errors
  leds: fix aat1290 build errors
  leds: aat1290: pass flags parameter to devm_gpiod_get
  leds: ktd2692: pass flags parameter to devm_gpiod_get
  drivers/leds: don't use module_init in non-modular leds-cobalt-raq.c
  leds: aat1290: add support for V4L2 Flash sub-device
  DT: aat1290: Document handling external strobe sources
  leds: max77693: add support for V4L2 Flash sub-device
  media: Add registration helpers for V4L2 flash sub-devices
  v4l: async: Add a pointer to of_node to struct v4l2_subdev, match it
  Documentation: leds: Add description of v4l2-flash sub-device
  leds: add BCM6358 LED driver
  leds: add DT binding for BCM6358 LED controller
  leds: fix brightness changing when software blinking is active
  Documentation: leds-lp5523: describe master fader attributes
  leds: lp5523: add master_fader support
  leds: leds-gpio: Allow compile test if !GPIOLIB
  leds: leds-gpio: Add missing #include <linux/of.h>
  gpiolib: Add missing dummies for the unified device properties interface
  ...
leds: fix brightness changing when software blinking is active 2015-05-25T20:26:47+00:00 Stas Sergeev stsp@list.ru 2015-05-14T15:24:02+00:00 76931edd54f87d1e49536cd068df4783fae24d45 The following sequence: echo timer >/sys/class/leds/<name>/trigger echo 1 >/sys/class/leds/<name>/brightness should change the ON brightness for blinking. The function led_set_brightness() was mistakenly initiating the delayed blink stop procedure, which resulted in no blinking with the timer trigger still active. This patch fixes the problem by changing led_set_brightness() to not initiate the delayed blink stop when brightness is not 0. CC: Richard Purdie <rpurdie@rpsys.net> CC: Kyungmin Park <kyungmin.park@samsung.com> CC: linux-leds@vger.kernel.org CC: linux-kernel@vger.kernel.org Acked-by: Jacek Anaszewski <j.anaszewski@samsung.com> Signed-off-by: Stas Sergeev <stsp@users.sourceforge.net> Signed-off-by: Bryan Wu <cooloney@gmail.com> 
The following sequence:
echo timer >/sys/class/leds/<name>/trigger
echo 1 >/sys/class/leds/<name>/brightness
should change the ON brightness for blinking.
The function led_set_brightness() was mistakenly initiating the
delayed blink stop procedure, which resulted in no blinking with
the timer trigger still active.

This patch fixes the problem by changing led_set_brightness()
to not initiate the delayed blink stop when brightness is not 0.

CC: Richard Purdie <rpurdie@rpsys.net>
CC: Kyungmin Park <kyungmin.park@samsung.com>
CC: linux-leds@vger.kernel.org
CC: linux-kernel@vger.kernel.org

Acked-by: Jacek Anaszewski <j.anaszewski@samsung.com>
Signed-off-by: Stas Sergeev <stsp@users.sourceforge.net>
Signed-off-by: Bryan Wu <cooloney@gmail.com>