Documentation: leds: improve readibility of multicolor doc

When reading the documentation of multicolor leds, the HTML output is
not easy to read. Improve it by adding a few markups, splitting the
console in a dedicated block.

Signed-off-by: Jean-Michel Hautbois <jeanmichel.hautbois@yoseli.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20250421-leds-doc-v1-1-9a32df7fc6f4@yoseli.org>
pull/1250/head
Jean-Michel Hautbois 2025-04-21 18:48:10 +02:00 committed by Jonathan Corbet
parent 8f82b560c5
commit 422f5b78bf
1 changed files with 51 additions and 31 deletions

View File

@ -18,24 +18,28 @@ 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 multi_* files. The order of the
colors will be arbitrary. The multi_index file can be read to determine the
Each colored LED will be indexed under the ``multi_*`` files. The order of the
colors will be arbitrary. The ``multi_index`` file can be read to determine the
color name to indexed value.
The multi_index file is an array that contains the string list of the colors as
they are defined in each multi_* array file.
The ``multi_index`` file is an array that contains the string list of the colors as
they are defined in each ``multi_*`` array file.
The multi_intensity is an array that can be read or written to for the
The ``multi_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.
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 max_brightness
-r--r--r-- 1 root root 4096 Oct 19 16:16 multi_index
-rw-r--r-- 1 root root 4096 Oct 19 16:16 multi_intensity
.. code-block:: console
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 max_brightness
-r--r--r-- 1 root root 4096 Oct 19 16:16 multi_index
-rw-r--r-- 1 root root 4096 Oct 19 16:16 multi_intensity
..
Multicolor Class Brightness Control
===================================
@ -43,27 +47,31 @@ The brightness level for each LED is calculated based on the color LED
intensity setting divided by the global max_brightness setting multiplied by
the requested brightness.
led_brightness = brightness * multi_intensity/max_brightness
``led_brightness = brightness * multi_intensity/max_brightness``
Example:
A user first writes the multi_intensity file with the brightness levels
for each LED that are necessary to achieve a certain color output from a
multicolor LED group.
cat /sys/class/leds/multicolor:status/multi_index
green blue red
.. code-block:: console
echo 43 226 138 > /sys/class/leds/multicolor:status/multi_intensity
# cat /sys/class/leds/multicolor:status/multi_index
green blue red
red -
intensity = 138
max_brightness = 255
green -
intensity = 43
max_brightness = 255
blue -
intensity = 226
max_brightness = 255
# echo 43 226 138 > /sys/class/leds/multicolor:status/multi_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 multicolor LED group by writing the
global 'brightness' control. Assuming a max_brightness of 255 the user
@ -71,16 +79,28 @@ may want to dim the LED color group to half. The user would write a value of
128 to the global brightness file then the values written to each LED will be
adjusted base on this value.
cat /sys/class/leds/multicolor:status/max_brightness
255
echo 128 > /sys/class/leds/multicolor:status/brightness
.. code-block:: console
adjusted_red_value = 128 * 138/255 = 69
adjusted_green_value = 128 * 43/255 = 21
adjusted_blue_value = 128 * 226/255 = 113
# cat /sys/class/leds/multicolor:status/max_brightness
255
# echo 128 > /sys/class/leds/multicolor:status/brightness
..
.. code-block:: none
adjusted_red_value = 128 * 138/255 = 69
adjusted_green_value = 128 * 43/255 = 21
adjusted_blue_value = 128 * 226/255 = 113
..
Reading the global brightness file will return the current brightness value of
the color LED group.
cat /sys/class/leds/multicolor:status/brightness
128
.. code-block:: console
# cat /sys/class/leds/multicolor:status/brightness
128
..