dm: Add support for LEDs
Add a simple uclass for LEDs, so that these can be controlled by the device
tree and activated when needed. LEDs are referred to by their label.
This implementation requires a driver for each type of LED (e.g GPIO, I2C).
Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/doc/device-tree-bindings/leds/common.txt b/doc/device-tree-bindings/leds/common.txt
new file mode 100644
index 0000000..2d88816
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+++ b/doc/device-tree-bindings/leds/common.txt
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+Common leds properties.
+
+Optional properties for child nodes:
+- label : The label for this LED. If omitted, the label is
+ taken from the node name (excluding the unit address).
+
+- linux,default-trigger : This parameter, if present, is a
+ string defining the trigger assigned to the LED. Current triggers are:
+ "backlight" - LED will act as a back-light, controlled by the framebuffer
+ system
+ "default-on" - LED will turn on (but for leds-gpio see "default-state"
+ property in Documentation/devicetree/bindings/gpio/led.txt)
+ "heartbeat" - LED "double" flashes at a load average based rate
+ "ide-disk" - LED indicates disk activity
+ "timer" - LED flashes at a fixed, configurable rate
+
+Examples:
+
+system-status {
+ label = "Status";
+ linux,default-trigger = "heartbeat";
+ ...
+};