Randy
Thanks for the review
On 4/2/20 10:47 PM, Randy Dunlap wrote:
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
Ack
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
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+====================================
+
+Description
+===========
+The multi color class groups monochrome LEDs and allows controlling two
multicolor
Ack
+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
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+
+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".
Ack
that are necessary from an
Ack and NACK the "from an". It is from a since R is a consonant
+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.
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+
+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
Ack
Dan
