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authorSimon Glass <sjg@chromium.org>2015-06-23 15:38:46 -0600
committerSimon Glass <sjg@chromium.org>2015-07-21 17:39:24 -0600
commit5ac76bad2277ed40f2a2112ffab0f156e3b599fb (patch)
tree83369bd34bf572f1df277e04e8772e8829a917b6 /doc
parent5917112c9e9f7a60062c604b3224bd5713c41f46 (diff)
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dm: led: Add a driver for GPIO-controlled LEDs
Add a simple driver which allows use of LEDs attached to GPIOs. The linux device tree binding is used. Signed-off-by: Simon Glass <sjg@chromium.org>
Diffstat (limited to 'doc')
-rw-r--r--doc/device-tree-bindings/leds/leds-gpio.txt52
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diff --git a/doc/device-tree-bindings/leds/leds-gpio.txt b/doc/device-tree-bindings/leds/leds-gpio.txt
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+LEDs connected to GPIO lines
+
+Required properties:
+- compatible : should be "gpio-leds".
+
+Each LED is represented as a sub-node of the gpio-leds device. Each
+node's name represents the name of the corresponding LED.
+
+LED sub-node properties:
+- gpios : Should specify the LED's GPIO, see "gpios property" in
+ Documentation/devicetree/bindings/gpio/gpio.txt. Active low LEDs should be
+ indicated using flags in the GPIO specifier.
+- label : (optional)
+ see Documentation/devicetree/bindings/leds/common.txt
+- linux,default-trigger : (optional)
+ see Documentation/devicetree/bindings/leds/common.txt
+- default-state: (optional) The initial state of the LED. Valid
+ values are "on", "off", and "keep". If the LED is already on or off
+ and the default-state property is set the to same value, then no
+ glitch should be produced where the LED momentarily turns off (or
+ on). The "keep" setting will keep the LED at whatever its current
+ state is, without producing a glitch. The default is off if this
+ property is not present.
+
+Examples:
+
+leds {
+ compatible = "gpio-leds";
+ hdd {
+ label = "IDE Activity";
+ gpios = <&mcu_pio 0 1>; /* Active low */
+ linux,default-trigger = "ide-disk";
+ };
+
+ fault {
+ gpios = <&mcu_pio 1 0>;
+ /* Keep LED on if BIOS detected hardware fault */
+ default-state = "keep";
+ };
+};
+
+run-control {
+ compatible = "gpio-leds";
+ red {
+ gpios = <&mpc8572 6 0>;
+ default-state = "off";
+ };
+ green {
+ gpios = <&mpc8572 7 0>;
+ default-state = "on";
+ };
+};