Messages in this thread Patch in this message |  | | Date | Mon, 10 Oct 2016 10:20:55 -0500 | From | Rob Herring <> | Subject | Re: [PATCH v2 2/3] input: pwm-beeper: add documentation for volume devicetree bindings |
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On Fri, Oct 07, 2016 at 09:08:17AM +0000, Schrempf Frieder wrote: > This patch adds the documentation for the devicetree bindings to set > the volume levels. > > Signed-off-by: Frieder Schrempf <frieder.schrempf@exceet.de> > --- > Changes in v2: > - split into 3 separate patches > - make volume properties optional > > .../devicetree/bindings/input/pwm-beeper.txt | 22 ++++++++++++++++++++++ > 1 file changed, 22 insertions(+) > > diff --git a/Documentation/devicetree/bindings/input/pwm-beeper.txt b/Documentation/devicetree/bindings/input/pwm-beeper.txt > index be332ae..6d8ba4e 100644 > --- a/Documentation/devicetree/bindings/input/pwm-beeper.txt > +++ b/Documentation/devicetree/bindings/input/pwm-beeper.txt > @@ -5,3 +5,25 @@ Registers a PWM device as beeper. > Required properties: > - compatible: should be "pwm-beeper" > - pwms: phandle to the physical PWM device > + > +Optional properties: > +- volume-levels: Array of distinct volume levels. These need to be in the > + range of 0 to 500, while 0 means 0% duty cycle (mute) and 500 means > + 50% duty cycle (max volume). > + Please note that the actual volume of most beepers is highly > + non-linear, which means that low volume levels are probably somewhere > + in the range of 1 to 30 (0.1-3% duty cycle).
What does the index correspond to? The linear volume?
> +- default-volume-level: the default volume level (index into the > + array defined by the "volume-levels" property) > + > +The volume level can be set via sysfs under /sys/class/input/inputX/volume. > +The maximum volume level index can be read from /sys/class/input/inputX/max_volume_level. > + > +Example: > + > + pwm-beeper { > + compatible = "pwm-beeper"; > + pwms = <&pwm4 0 5000>; > + volume-levels = <0 8 20 40 500>; > + default-volume-level = <4>; > + }; > -- > 1.9.1
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