This patch adds the documentation for the devicetree bindings to set
the volume levels.
Signed-off-by: Frieder Schrempf <frieder.schrempf@xxxxxxxxx>
Acked-by: Rob Herring <robh@xxxxxxxxxx>
---
.../devicetree/bindings/input/pwm-beeper.txt | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/Documentation/devicetree/bindings/input/pwm-beeper.txt b/Documentation/devicetree/bindings/input/pwm-beeper.txt
index 8fc0e48c20db..93cab5eee9f2 100644
--- a/Documentation/devicetree/bindings/input/pwm-beeper.txt
+++ b/Documentation/devicetree/bindings/input/pwm-beeper.txt
@@ -9,6 +9,15 @@ Required properties:
Optional properties:
- amp-supply: phandle to a regulator that acts as an amplifier for the beeper
- beeper-hz: bell frequency in Hz
+- volume-levels: Array of PWM duty cycle values that correspond to
+ linear 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).
+- default-volume-level: the default volume level (index into the
+ array defined by the "volume-levels" property)
Example:
@@ -21,4 +30,6 @@ beeper {
compatible = "pwm-beeper";
pwms = <&pwm0>;
amp-supply = <&beeper_amp>;
+ volume-levels = <0 8 20 40 500>;
+ default-volume-level = <4>;
};
--
2.39.0
