Hi,
Here are a few changes for you to consider:
On 4/2/20 1:42 PM, Dan Murphy wrote:
> Introduce a multicolor class that groups colored LEDs
> within a LED node.
>
> The multi color class groups monochrome LEDs and allows controlling two
multicolor
> 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.
>
> Signed-off-by: Dan Murphy <dmurphy@xxxxxx>
> ---
> diff --git a/Documentation/leds/leds-class-multicolor.rst b/Documentation/leds/leds-class-multicolor.rst
> new file mode 100644
> index 000000000000..5bb004999248
> --- /dev/null
> +++ b/Documentation/leds/leds-class-multicolor.rst
> @@ -0,0 +1,95 @@
> +====================================
> +Multi Color LED handling under Linux
Multicolor
> +====================================
> +
> +Description
> +===========
> +The multi color class groups monochrome LEDs and allows controlling two
multicolor
> +aspects of the final combined color: hue and lightness. The former is
> +controlled via the color_intensity array file 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.
> +
> +Multicolor Class Control
> +========================
> +The multicolor class presents files that groups the colors as indexes in an
> +array. These files are children 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 be indexed under the color_* files. The order of the
> +colors are arbitrary the color_index file can be read to determine the color
> +to index value.
> +
> +The color_index file is an array that contains the string list of the colors as
> +they are defined in each color_* array file.
> +
> +The color_intensity is an array that can be read or written to for the
> +individual color intensities. All elements within this array must be written in
> +order for the color LED intensities to be updated.
> +
> +The color_max_intensity is an array that can be read to indicate each color LED
> +maximum intensity value.
> +
> +The num_color_leds file returns the total number of color LEDs that are
> +presented in each color_* array.
> +
> +Directory Layout Example
> +========================
> +root:/sys/class/leds/multicolor:status# ls -lR
> +-rw-r--r-- 1 root root 4096 Oct 19 16:16 brightness
> +-r--r--r-- 1 root root 4096 Oct 19 16:16 color_index
> +-rw-r--r-- 1 root root 4096 Oct 19 16:16 color_intensity
> +-r--r--r-- 1 root root 4096 Oct 19 16:16 num_color_leds
> +
> +Multicolor Class Brightness Control
> +===================================
> +The multiclor class framework will calculate each monochrome LEDs intensity.
multicolor
> +
> +The brightness level for each LED is calculated based on the color LED
> +intensity setting divided by the parent max_brightness setting multiplied by
> +the requested brightness.
> +
> +led_brightness = brightness * color_intensity/max_brightness
> +
> +Example:
> +A user first writes the color_intensity file with the brightness levels
> +that for each LED that is necessary to achieve a blueish violet output from a
drop first "that".
that are necessary from an
> +RGB LED group.
> +
> +cat /sys/class/leds/multicolor:status/color_index
> +green blue red
> +
> +echo 43 226 138 > /sys/class/leds/multicolor:status/color_intensity
> +
> +red -
> + intensity = 138
> + max_brightness = 255
> +green -
> + intensity = 43
> + max_brightness = 255
> +blue -
> + intensity = 226
> + max_brightness = 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
value.
> +
> +cat /sys/class/leds/multicolor:status/max_brightness
> +255
> +echo 128 > /sys/class/leds/multicolor:status/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/multicolor:status/brightness
> +128
> diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
> index d82f1dea3711..2e4611b25054 100644
> --- a/drivers/leds/Kconfig
> +++ b/drivers/leds/Kconfig
> @@ -30,6 +30,16 @@ config LEDS_CLASS_FLASH
> for the flash related features of a LED device. It can be built
> as a module.
>
> +config LEDS_CLASS_MULTI_COLOR
> + tristate "LED Multi Color LED Class Support"
Multicolor
> + depends on LEDS_CLASS
> + help
> + This option enables the multicolor LED sysfs class in /sys/class/leds.
> + It wraps LED class and adds multicolor LED specific sysfs attributes
> + and kernel internal API to it. You'll need this to provide support
> + for multicolor LEDs that are grouped together. This class is not
> + intended for single color LEDs. It can be built as a module.
> +
> config LEDS_BRIGHTNESS_HW_CHANGED
> bool "LED Class brightness_hw_changed attribute support"
> depends on LEDS_CLASS
thanks.
--
~Randy
