[PATCH v5 15/16] pwm-backlight: Add rudimentary device tree support
Stephen Warren
swarren at wwwdotorg.org
Sat Mar 31 06:04:28 EST 2012
On 03/28/2012 08:33 AM, Thierry Reding wrote:
> This commit adds very basic support for device tree probing. Currently,
> only a PWM and a list of distinct brightness levels can be specified.
> Enabling or disabling backlight power via GPIOs is not yet supported.
>
> Signed-off-by: Thierry Reding <thierry.reding at avionic-design.de>
> diff --git a/Documentation/devicetree/bindings/video/backlight/pwm-backlight b/Documentation/devicetree/bindings/video/backlight/pwm-backlight
> +Required properties:
> + - compatible: "pwm-backlight"
> + - pwms: OF device-tree PWM specification (see PWM binding[0])
> + - num-brightness-levels: number of distinct brightness levels
Do we need the "num-brightness-levels" property at all; it's just the
length of the brightness-levels property.
> + - brightness-levels: Array of distinct brightness levels. Typically these
> + are in the range from 0 to 255, but any range starting at 0 will do.
> + The actual brightness level (PWM duty cycle) will be interpolated
> + from these values. 0 means a 0% duty cycle (darkest/off), while the
> + last value in the array represents a 100% duty cycle (brightest).
...> +Example:
> +
> + backlight {
> + compatible = "pwm-backlight";
> + pwms = <&pwm 0 5000000>;
> +
> + num-brightness-levels = <8>;
> + brightness-levels = <0 4 8 16 32 64 128 255>;
> + default-brightness-level = <6>;
> + };
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