On Thu, Apr 07, 2016 at 03:58:40PM +0000, Schrempf Frieder wrote:
> Make the driver accept different volume levels via sysfs.
> This can be helpful if the beep/bell sound intensity needs
> to be adapted to the environment of the device.
It is preferred that bindings be a separate patch. Also, this is 2
independent features: the sysfs interface and DT properties. So that is
probably 3 patches.
Also, sysfs interfaces are supposed to be documented.
>
> The number of volume levels available and their values can
> be specified via device tree (similar to pwm-backlight).
>
> This patch was tested with linux-imx 3.10.17 and was
> applied to current mainline without any changes.
You need to test with something not 3 years old...
>
> Signed-off-by: Frieder Schrempf <frieder.schre...@exceet.de>
> ---
> .../devicetree/bindings/input/pwm-beeper.txt | 20 ++++
> drivers/input/misc/pwm-beeper.c | 109 ++++++++++++++++++-
> 2 files changed, 126 insertions(+), 3 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/input/pwm-beeper.txt
> b/Documentation/devicetree/bindings/input/pwm-beeper.txt
> index be332ae..153cd3f 100644
> --- a/Documentation/devicetree/bindings/input/pwm-beeper.txt
> +++ b/Documentation/devicetree/bindings/input/pwm-beeper.txt
> @@ -5,3 +5,23 @@ Registers a PWM device as beeper.
> Required properties:
> - compatible: should be "pwm-beeper"
> - pwms: phandle to the physical PWM device
> +- 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).
Where does the scale of 0-500 come from? It is tenth of a percent?
How many array entries?
> + 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)
> +
> +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>;
> + };
