Messages in this thread Patch in this message |  | | Subject | Re: [PATCH] cleanup LED documentation and make it match reality | From | Jacek Anaszewski <> | Date | Mon, 03 Oct 2016 11:27:53 +0200 |
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Hi Pavel,
Thanks for the patch.
On 10/03/2016 10:10 AM, Pavel Machek wrote: > > sysfs-class-led fails to mention some important details. Also fix led > vs LED and english. > > Signed-off-by: Pavel Machek <pavel@ucw.cz> > > --- a/Documentation/ABI/testing/sysfs-class-led > +++ b/Documentation/ABI/testing/sysfs-class-led > @@ -4,16 +4,25 @@ KernelVersion: 2.6.17 > 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 > + 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. > > + Writing 0 to this file clears active trigger. > + > + Writing non-zero to this file while trigger is active changes the > + top brightness trigger is going to use.
This is true only in case of timer trigger, as it uses blink_brightness property from struct led_classdev to cache current brightness, when the the LED is in the off cycle. This is part of software blink fallback functionality.
In case of heartbeat trigger max_brightness is always used for top level brightness. We'd need to refactor the trigger a bit to allow for different top brightness levels.
> + > + > What: /sys/class/leds/<led>/max_brightness > Date: March 2006 > KernelVersion: 2.6.17 > Contact: Richard Purdie <rpurdie@rpsys.net> > Description: > - Maximum brightness level for this led, default is 255 (LED_FULL). > + Maximum brightness level for this LED, default is 255 (LED_FULL). > + > + If the LED does not support different brightness levels, this > + should be 1. > > What: /sys/class/leds/<led>/trigger > Date: March 2006 > @@ -21,7 +30,7 @@ KernelVersion: 2.6.17 > Contact: Richard Purdie <rpurdie@rpsys.net> > Description: > Set the trigger for this LED. A trigger is a kernel based source > - of led events. > + of LED events. > You can change triggers in a similar manner to the way an IO > scheduler is chosen. Trigger specific parameters can appear in > /sys/class/leds/<led> once a given trigger is selected. >
-- Best regards, Jacek Anaszewski
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