Rockchip DRM backlight device
================================

Rockchip display controller(see VOP bindings[0]) support CABC function,
and the CABC function required using VOP self pwm to control backlight,
This backlight device manager the backlight PWM, auto select correct
PWM for backlight.

Required properties:
- compatible: Should be "rockchip,drm-backlight"

Other properties are same to commom PWM backlight bindings[1].

[0]: Documentation/devicetree/bindings/display/rockchip/rockchip-vop.txt
[1]: Documentation/devicetree/bindings/leds/backlight/pwm-backlight.txt

example:

backlight {
	compatible = "rockchip,drm-backlight";
	pwms = <&pwm 0 5000000>;

	brightness-levels = <0 4 8 16 32 64 128 255>;
	default-brightness-level = <6>;

	power-supply = <&vdd_bl_reg>;
	enable-gpios = <&gpio 58 0>;
};