[PATCH 03/11] doc: cmd: document the led shell command

[Quentin Schulz]

From: Quentin Schulz <quentin.schulz at cherry.de>

This adds documentation on how to use the led shell command.

Signed-off-by: Quentin Schulz <quentin.schulz at cherry.de>
---
 doc/usage/cmd/led.rst | 95 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 95 insertions(+)

diff --git a/doc/usage/cmd/led.rst b/doc/usage/cmd/led.rst
new file mode 100644
index 00000000000..b5623895c7e
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+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+.. index::
+   single: led (command)
+
+led command
+===========
+
+Synopsis
+--------
+
+::
+
+    led <led_label> <on|off|toggle>
+    led <led_label> blink <blink-freq in ms>
+    led <led_label>
+    led list
+
+led <led_label>
+---------------
+
+Get state of the LED whose label is the one passed as ``<led_label>`` argument.
+
+Provided ``<led_label>`` is *module_led*, the possible outputs for this command
+are::
+
+    LED 'module_led': off
+    LED 'module_led': on
+    LED 'module_led': blink
+
+led <led_label> on|off|toggle
+-----------------------------
+
+Turn on, off or toggle state of the LED whose label is the one passed as
+``<led_label>`` argument.
+
+led <led_label> blink <blink-freq in ms>
+----------------------------------------
+
+Make the LED whose label is the one passed as ``<led_label>`` argument blink at
+a frequency specified by the argument ``<blink-freq in ms>``.
+
+The frequency is parsed as a decimal number and its unit is milliseconds. The
+duty cycle is 50%. Example::
+
+    led blue blink 1000
+
+will make the *blue*-labeled LED blink with a state (on or off) kept for 500ms
+before switching to the other state (respectively off or on) for 500ms,
+looping endlessly.
+
+led list
+--------
+
+List all available LEDs by their label and provide their known state, which can
+be either *off*, *on* or *blink*.
+
+If a LED has not been probed yet, its state will be shown as *<inactive>* in the
+list.
+
+Examples
+--------
+
+::
+
+    => led list
+    module_led      on
+    sd_card_led     <inactive>
+    => led module_led
+    LED 'module_led': on
+    => led module_led off
+    => led module_led
+    LED 'module_led': off
+    => led module_led toggle
+    => led module_led
+    LED 'module_led': on
+    => led module_led toggle
+    => led module_led
+    LED 'module_led': off
+    => led module_led blink 1000
+    => led module_led
+    LED 'module_led': blink
+    => led sd_card_led
+    LED 'sd_card_led': off
+    => led list
+    module_led      blink
+    sd_card_led     off
+
+Configuration
+-------------
+
+The *led* commands are only available if ``CONFIG_CMD_LED=y``.
+
+The *led <led_label> blink* command is only available if ``CONFIG_CMD_LED=y``
+and either ``CONFIG_LED_BLINK=y`` or ``CONFIG_LED_SW_BLINK=y``.

-- 
2.51.1