Hi Dan, Thank you for the v9. This patch should me melded with 5/15. On 9/25/19 7:46 PM, Dan Murphy wrote: > Add a documentation of LED Multicolor LED class specific > sysfs attributes. > > Add multicolor framework class documentation describing the > usage of the files created. > > Signed-off-by: Dan Murphy <dmurphy@xxxxxx> > --- > .../ABI/testing/sysfs-class-led-multicolor | 35 +++++++ > Documentation/leds/index.rst | 1 + > Documentation/leds/leds-class-multicolor.rst | 96 +++++++++++++++++++ > 3 files changed, 132 insertions(+) > create mode 100644 Documentation/ABI/testing/sysfs-class-led-multicolor > create mode 100644 Documentation/leds/leds-class-multicolor.rst > > diff --git a/Documentation/ABI/testing/sysfs-class-led-multicolor b/Documentation/ABI/testing/sysfs-class-led-multicolor > new file mode 100644 > index 000000000000..65cb43de26e6 > --- /dev/null > +++ b/Documentation/ABI/testing/sysfs-class-led-multicolor > @@ -0,0 +1,35 @@ > +What: /sys/class/leds/<led>/brightness > +Date: Sept 2019 > +KernelVersion: 5.5 > +Contact: Dan Murphy <dmurphy@xxxxxx> > +Description: read/write > + Writing to this file will update all LEDs within the group to a > + calculated percentage of what each color LED intensity is set > + to. The percentage is calculated via the equation below: > + > + led_brightness = brightness * <color>_intensity/<color>_max_intensity > + > + For additional details please refer to > + Documentation/leds/leds-class-multicolor.rst. > + > + The value of the color is from 0 to > + /sys/class/leds/<led>/max_brightness. > + > +What: /sys/class/leds/<led>/colors/<color>_intensity > +Date: Sept 2019 > +KernelVersion: 5.5 > +Contact: Dan Murphy <dmurphy@xxxxxx> > +Description: read/write > + The <color>_intensity file is created based on the color > + defined by the registrar of the class. > + There is one file per color presented. > + > + The value of the color is from 0 to > + /sys/class/leds/<led>/colors/<color>_max_intensity. > + > +What: /sys/class/leds/<led>/colors/<color>_max_intensity > +Date: Sept 2019 > +KernelVersion: 5.5 > +Contact: Dan Murphy <dmurphy@xxxxxx> > +Description: read only > + Maximum intensity level for the LED color. > diff --git a/Documentation/leds/index.rst b/Documentation/leds/index.rst > index 060f4e485897..bc70c6aa7138 100644 > --- a/Documentation/leds/index.rst > +++ b/Documentation/leds/index.rst > @@ -9,6 +9,7 @@ LEDs > > leds-class > leds-class-flash > + leds-class-multicolor > ledtrig-oneshot > ledtrig-transient > ledtrig-usbport > 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. > + > +Multicolor Class Control > +======================== > +The multicolor class presents the LED groups under a directory called "colors". > +This directory is a child under the LED parent node created by the led_class > +framework. The led_class framework is documented in led-class.rst within this > +documentation directory. > + > +Each colored LED will have two files created under the colors directory > +<color>_intensity and <color>_max_intensity. These files will contain > +one of LED_COLOR_ID_* definitions from the header > +include/dt-bindings/leds/common.h. > + > +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 > + > +Multicolor Class Brightness Control > +=================================== > +The multiclor class framework will calculate each monochrome LEDs intensity. > + > +The brightness level for each LED is calculated based on the color LED > +intensity setting divided by the color LED max intensity setting multiplied by > +the requested brightness. > + > +led_brightness = brightness * <color>_intensity/<color>_max_intensity > + > +Example: > +Three LEDs are present in the group as defined in "Directory Layout Example" > +within this document. > + > +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 > + > +red - > + intensity = 138 > + max_intensity = 255 > +green - > + intensity = 43 > + max_intensity = 255 > +blue - > + intensity = 226 > + max_intensity = 255 > + > +The user can control the brightness of that RGB group by writing the parent > +'brightness' control. Assuming a parent max_brightness of 255 the user may want > +to dim the LED color group to half. The user would write a value of 128 to the > +parent brightness file then the values written to each LED will be adjusted > +base on this value > + > +cat /sys/class/leds/rgb:grouped_leds/max_brightness > +255 > +echo 128 > /sys/class/leds/rgb:grouped_leds/brightness > + > +adjusted_red_value = 128 * 138/255 = 69 > +adjusted_green_value = 128 * 43/255 = 21 > +adjusted_blue_value = 128 * 226/255 = 113 > + > +Reading the parent brightness file will return the current brightness value of > +the color LED group. > + > +cat /sys/class/leds/rgb:grouped_leds/max_brightness > +255 > + > +echo 128 > /sys/class/leds/rgb:grouped_leds/brightness > + > +cat /sys/class/leds/rgb:grouped_leds/brightness > +128 > -- Best regards, Jacek Anaszewski
