| Message ID | 20161101133748.7168-1-hdegoede@redhat.com (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
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. Thanks, 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@redhat.com> > --- > 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@rpsys.net> > 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 > * > -- To unsubscribe from this list: send the line "unsubscribe platform-driver-x86" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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 ? Regards, Hans > > Thanks, > 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@redhat.com> >> --- >> 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@rpsys.net> >> 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 >> * >> > -- To unsubscribe from this list: send the line "unsubscribe platform-driver-x86" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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@redhat.com> >>> --- >>> 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@rpsys.net> >>> 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 >>> * >>> >> > > >
Hi, On 08-11-16 14:08, Jacek Anaszewski wrote: > 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 Thank you. Darren, can you merge this tag and patches 2-4 of this series please ? Regards, Hans -- To unsubscribe from this list: send the line "unsubscribe platform-driver-x86" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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@rpsys.net> 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 *
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@redhat.com> --- 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(-)