On 11/08/2016 01:31 PM, Hans de Goede wrote:
> Hi,
>
> On 08-11-16 12:52, Jacek Anaszewski wrote:
>> Hi Hans,
>>
>> I've tested it with userspace test application and it seems to work
>> well both with hardware leds-aat1290 driver and drivers/leds/uleds.c.
>>
>> Applied to the for-next branch of linux-leds.git.
>
> Great, thank you. Can you also add a stable branch / tag with this
> commit which the platform/x86 maintainer can merge into his tree,
> so that he can merge the platform/x86 driver changes which depend
> up on the new led_notify_brightness_change() function ?
Sure. I've created stable led_brightness_pollpri branch on
git://git.kernel.org/pub/scm/linux/kernel/git/j.anaszewski/linux-leds.git
Best regards,
Jacek Anaszewski
>> On 11/01/2016 02:37 PM, Hans de Goede wrote:
>>> Add support for userspace using poll() for POLL_PRI on the sysfs
>>> brightness
>>> attr to watch for brightness changes.
>>>
>>> This commit adds a led_notify_brightness_change helper function for
>>> waking up any poll() waiters; and calls this after any brightness
>>> changes
>>> (after any led_classdev->brightness_set[_blocking] calls have
>>> completed).
>>>
>>> In some use-cases led hardware may autonomously change its brightness,
>>> e.g. the keyboard backlight used on some laptops is controlled by a
>>> hardwired (firmware handled) hotkey. led_notify_brightness_change is
>>> exported for use by drivers which can detect such autonomous changes.
>>>
>>> This commit also updates the Documentation/ABI/testing/sysfs-class-led
>>> documentation to document that userspace may now poll on the brightness
>>> attribute.
>>>
>>> Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
>>> ---
>>> Changes in v2:
>>> -Wakeup / notify userspace on any brightness changes, not just on
>>> autonomous changes done by the hw
>>> Changes in v3:
>>> -Rebase on linux-leds/for-next
>>> Changes in v4:
>>> -No Changes
>>> ---
>>> Documentation/ABI/testing/sysfs-class-led | 8 ++++++--
>>> drivers/leds/led-class.c | 9 +++++++++
>>> drivers/leds/led-core.c | 16 +++++++++++++++-
>>> include/linux/leds.h | 12 ++++++++++++
>>> 4 files changed, 42 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/Documentation/ABI/testing/sysfs-class-led
>>> b/Documentation/ABI/testing/sysfs-class-led
>>> index 491cdee..0af5191 100644
>>> --- a/Documentation/ABI/testing/sysfs-class-led
>>> +++ b/Documentation/ABI/testing/sysfs-class-led
>>> @@ -1,12 +1,16 @@
>>> What: /sys/class/leds/<led>/brightness
>>> -Date: March 2006
>>> -KernelVersion: 2.6.17
>>> +Date: March 2006 (poll October 2016)
>>> +KernelVersion: 2.6.17 (poll since 4.10)
>>> Contact: Richard Purdie <rpurdie@xxxxxxxxx>
>>> Description:
>>> Set the brightness of the LED. Most LEDs don't
>>> have hardware brightness support, so will just be turned on for
>>> non-zero brightness settings. The value is between 0 and
>>> /sys/class/leds/<led>/max_brightness.
>>> + The file supports poll() to detect brightness changes, in
>>> + some cases the hardware / firmware may change the brightness
>>> + autonomously, poll() should be woken up in this case too,
>>> + but not all drivers may support this.
>>>
>>> Writing 0 to this file clears active trigger.
>>>
>>> diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
>>> index 731e4eb..c8d2d67 100644
>>> --- a/drivers/leds/led-class.c
>>> +++ b/drivers/leds/led-class.c
>>> @@ -204,6 +204,14 @@ int led_classdev_register(struct device *parent,
>>> struct led_classdev *led_cdev)
>>> dev_warn(parent, "Led %s renamed to %s due to name collision",
>>> led_cdev->name, dev_name(led_cdev->dev));
>>>
>>> + led_cdev->brightness_kn = sysfs_get_dirent(led_cdev->dev->kobj.sd,
>>> + "brightness");
>>> + if (!led_cdev->brightness_kn) {
>>> + dev_err(led_cdev->dev, "Error getting brightness
>>> kernfs_node\n");
>>> + device_unregister(led_cdev->dev);
>>> + return -ENODEV;
>>> + }
>>> +
>>> #ifdef CONFIG_LEDS_TRIGGERS
>>> init_rwsem(&led_cdev->trigger_lock);
>>> #endif
>>> @@ -255,6 +263,7 @@ void led_classdev_unregister(struct led_classdev
>>> *led_cdev)
>>>
>>> flush_work(&led_cdev->set_brightness_work);
>>>
>>> + sysfs_put(led_cdev->brightness_kn);
>>> device_unregister(led_cdev->dev);
>>>
>>> down_write(&leds_list_lock);
>>> diff --git a/drivers/leds/led-core.c b/drivers/leds/led-core.c
>>> index 2d0c75a..af78279 100644
>>> --- a/drivers/leds/led-core.c
>>> +++ b/drivers/leds/led-core.c
>>> @@ -33,16 +33,24 @@ static int __led_set_brightness(struct
>>> led_classdev *led_cdev,
>>>
>>> led_cdev->brightness_set(led_cdev, value);
>>>
>>> + led_notify_brightness_change(led_cdev);
>>> +
>>> return 0;
>>> }
>>>
>>> static int __led_set_brightness_blocking(struct led_classdev *led_cdev,
>>> enum led_brightness value)
>>> {
>>> + int ret;
>>> +
>>> if (!led_cdev->brightness_set_blocking)
>>> return -ENOTSUPP;
>>>
>>> - return led_cdev->brightness_set_blocking(led_cdev, value);
>>> + ret = led_cdev->brightness_set_blocking(led_cdev, value);
>>> + if (ret >= 0)
>>> + led_notify_brightness_change(led_cdev);
>>> +
>>> + return ret;
>>> }
>>>
>>> static void led_timer_function(unsigned long data)
>>> @@ -308,6 +316,12 @@ int led_update_brightness(struct led_classdev
>>> *led_cdev)
>>> }
>>> EXPORT_SYMBOL_GPL(led_update_brightness);
>>>
>>> +void led_notify_brightness_change(struct led_classdev *led_cdev)
>>> +{
>>> + sysfs_notify_dirent(led_cdev->brightness_kn);
>>> +}
>>> +EXPORT_SYMBOL_GPL(led_notify_brightness_change);
>>> +
>>> /* Caller must ensure led_cdev->led_access held */
>>> void led_sysfs_disable(struct led_classdev *led_cdev)
>>> {
>>> diff --git a/include/linux/leds.h b/include/linux/leds.h
>>> index 52993de..f034c2d 100644
>>> --- a/include/linux/leds.h
>>> +++ b/include/linux/leds.h
>>> @@ -13,6 +13,7 @@
>>> #define __LINUX_LEDS_H_INCLUDED
>>>
>>> #include <linux/device.h>
>>> +#include <linux/kernfs.h>
>>> #include <linux/list.h>
>>> #include <linux/mutex.h>
>>> #include <linux/rwsem.h>
>>> @@ -93,6 +94,8 @@ struct led_classdev {
>>>
>>> struct work_struct set_brightness_work;
>>>
>>> + struct kernfs_node *brightness_kn;
>>> +
>>> #ifdef CONFIG_LEDS_TRIGGERS
>>> /* Protects the trigger data below */
>>> struct rw_semaphore trigger_lock;
>>> @@ -192,6 +195,15 @@ extern int led_set_brightness_sync(struct
>>> led_classdev *led_cdev,
>>> extern int led_update_brightness(struct led_classdev *led_cdev);
>>>
>>> /**
>>> + * led_notify_brightness_change - Notify userspace of brightness
>>> changes
>>> + * @led_cdev: the LED to do the notify on
>>> + *
>>> + * Let any users waiting for POLL_PRI on the led's brightness sysfs
>>> + * atrribute know that the brightness has been changed.
>>> + */
>>> +extern void led_notify_brightness_change(struct led_classdev
>>> *led_cdev);
>>> +
>>> +/**
>>> * led_sysfs_disable - disable LED sysfs interface
>>> * @led_cdev: the LED to set
>>> *
>>>
>>
>
>
>
--
Best regards,
Jacek Anaszewski
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