Hi! > diff --git a/Documentation/leds/leds-class-multicolor.rst > b/Documentation/leds/leds-class-multicolor.rst > new file mode 100644 > index 000000000000..87a1588d7619 > --- /dev/null > +++ b/Documentation/leds/leds-class-multicolor.rst > @@ -0,0 +1,96 @@ > +==================================== > +Multi Color LED handling under Linux > +==================================== > + > +Description > +=========== > +The multi color class groups monochrome LEDs and allows controlling two > +aspects of the final combined color: hue and lightness. The former is > +controlled via <color>_intensity files and the latter is controlled > +via brightness file. > + > +For more details on hue and lightness notions please refer to > +https://en.wikipedia.org/wiki/CIECAM02. > + > +Note that intensity files only cache the written value and the actual > +change of hardware state occurs upon writing brightness file. This > +allows for changing many factors of the perceived color in a virtually > +unnoticeable way for the human observer.
So unlike previous versions, userspace will need to write 4 files
instead of one in the common case.
> +Directory Layout Example
> +========================
> +root:/sys/class/leds/rgb:grouped_leds# ls -lR colors/
> +-rw-rwxr-- 1 root root 4096 Jul 7 03:10 red_max_intensity
> +--w--wx-w- 1 root root 4096 Jul 7 03:10 red_intensity
> +-rw-rwxr-- 1 root root 4096 Jul 7 03:10 green_max_intensity
> +--w--wx-w- 1 root root 4096 Jul 7 03:10 green_intensity
> +-rw-rwxr-- 1 root root 4096 Jul 7 03:10 blue_max_intensity
> +--w--wx-w- 1 root root 4096 Jul 7 03:10 blue_intensity
Permissions are way off here.
> +A user first writes the color LED brightness file with the brightness level
> that
> +is necessary to achieve a blueish violet output from the RGB LED group.
> +
> +echo 138 > /sys/class/leds/rgb:grouped_leds/red_intensity
> +echo 43 > /sys/class/leds/rgb:grouped_leds/green_intensity
> +echo 226 > /sys/class/leds/rgb:grouped_leds/blue_intensity
No, you can't tell what kind of color this will result in.
Will you be on ELCE/OSS in Lyon?
Best regards,
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures)
http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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