On Wed, Dec 12, 2018 at 12:16:42PM +0100, Krzysztof Kozlowski wrote: > 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, I misunderstood that these triggers applied to this. Is there any point to supporting these modes? Aren't they just a subset or simplification of a pattern? Can we control the timer frequency from DT? The pattern could address that limitation. > + - pattern : The pattern is given by a series of tuples, of Don't you need one-shot vs. repeat modes for patterns too? I could imagine you'd want a pattern for any trigger. > + 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 >
