Document new linux,trigger-pattern property for initialization of LED
pattern trigger.
Signed-off-by: Krzysztof Kozlowski <krzk@xxxxxxxxxx>
---
Documentation/devicetree/bindings/leds/common.txt | 36 +++++++++++++++++++++++
1 file changed, 36 insertions(+)
diff --git a/Documentation/devicetree/bindings/leds/common.txt b/Documentation/devicetree/bindings/leds/common.txt
index aa1399814a2a..3daccd4ea8a3 100644
--- a/Documentation/devicetree/bindings/leds/common.txt
+++ b/Documentation/devicetree/bindings/leds/common.txt
@@ -37,6 +37,42 @@ Optional properties for child nodes:
"ide-disk" - LED indicates IDE disk activity (deprecated),
in new implementations use "disk-activity"
"timer" - LED flashes at a fixed, configurable rate
+ "pattern" - LED alters the brightness for the specified duration with one
+ software timer (requires "led-pattern" property)
+
+- led-pattern : String with default pattern for certain triggers. Each trigger
+ may parse this string differently:
+ - one-shot : two numbers specifying delay on and delay off,
+ - timer : two numbers specifying delay on and delay off,
+ - pattern : The pattern is given by a series of tuples, of
+ brightness and duration (ms). The LED is expected to traverse
+ the series and each brightness value for the specified
+ duration. Duration of 0 means brightness should immediately
+ change to new value.
+
+ 1. For gradual dimming, the dimming interval now is set as 50
+ milliseconds. So the tuple with duration less than dimming
+ interval (50ms) is treated as a step change of brightness,
+ i.e. the subsequent brightness will be applied without adding
+ intervening dimming intervals.
+
+ The gradual dimming format of the software pattern values should be:
+ "brightness_1 duration_1 brightness_2 duration_2 brightness_3
+ duration_3 ...".
+ For example "0 1000 255 2000" will make the LED go gradually
+ from zero-intensity to max (255) intensity in 1000
+ milliseconds, then back to zero intensity in 2000
+ milliseconds.
+
+ 2. To make the LED go instantly from one brightness value to
+ another, pattern should use zero-time lengths (the brightness
+ must be same as the previous tuple's). So the format should be:
+ "brightness_1 duration_1 brightness_1 0 brightness_2
+ duration_2 brightness_2 0 ...".
+ For example "0 1000 0 0 255 2000 255 0" will make the LED
+ stay off for one second, then stay at max brightness for two
+ seconds.
+
- led-max-microamp : Maximum LED supply current in microamperes. This property
can be made mandatory for the board configurations
--
2.7.4
