From 051c448c8b2a0b0ae9a682b4b1fde35f7a127c77 Mon Sep 17 00:00:00 2001 From: Christian Marangi Date: Tue, 1 Oct 2024 14:24:42 +0200 Subject: doc: introduce led.rst documentation Introduce simple led.rst documentation to document all the additional Kconfig and the current limitation of LED_BLINK and GPIO software blink. Also add missing definition for sw_blink in led_uc_plat struct. Signed-off-by: Christian Marangi Reviewed-by: Simon Glass --- include/led.h | 41 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+) (limited to 'include') diff --git a/include/led.h b/include/led.h index 19d92d6441a..64247cd3a70 100644 --- a/include/led.h +++ b/include/led.h @@ -11,6 +11,46 @@ #include #include +/** + * DOC: Overview + * + * Generic LED API provided when a supported compatible is defined in DeviceTree. + * + * To enable support for LEDs, enable the `CONFIG_LED` Kconfig option. + * + * The most common implementation is for GPIO-connected LEDs. If using GPIO-connected LEDs, + * enable the `LED_GPIO` Kconfig option. + * + * `LED_BLINK` support requires LED driver support and is therefore optional. If LED blink + * functionality is needed, enable the `LED_BLINK` Kconfig option. If LED driver doesn't + * support HW Blink, SW Blink can be used with the Cyclic framework by enabling the + * CONFIG_LED_SW_BLINK. + * + * Boot and Activity LEDs are also supported. These LEDs can signal various system operations + * during runtime, such as boot initialization, file transfers, and flash write/erase operations. + * + * To enable a Boot LED, enable `CONFIG_LED_BOOT` and define in `/options/u-boot` root node the + * property `boot-led`. This will enable the specified LED to blink and turn ON when + * the bootloader initializes correctly. + * + * To enable an Activity LED, enable `CONFIG_LED_ACTIVITY` and define in `/options/u-boot` root + * node the property `activity-led`. + * This will enable the specified LED to blink and turn ON during file transfers or flash + * write/erase operations. + * + * Both Boot and Activity LEDs provide a simple API to turn the LED ON or OFF: + * `led_boot_on()`, `led_boot_off()`, `led_activity_on()`, and `led_activity_off()`. + * + * Both configurations can optionally define a `boot/activity-led-period` property + * if `CONFIG_LED_BLINK` or `CONFIG_LED_SW_BLINK` is enabled for LED blink operations, which + * is usually used by the Activity LED. If not defined the default value of 250 (ms) is used. + * + * When `CONFIG_LED_BLINK` or `CONFIG_LED_SW_BLINK` is enabled, additional APIs are exposed: + * `led_boot_blink()` and `led_activity_blink()`. Note that if `CONFIG_LED_BLINK` or + * `CONFIG_LED_SW_BLINK` is disabled, these APIs will behave like the `led_boot_on()` and + * `led_activity_on()` APIs, respectively. + */ + struct udevice; enum led_state_t { @@ -41,6 +81,7 @@ struct led_sw_blink { * * @label: LED label * @default_state: LED default state + * @sw_blink: LED software blink struct */ struct led_uc_plat { const char *label; -- cgit v1.3.1