Device-Tree bindings for Rockchip SoC display controller (VOP / LCDC)
VOP (Video Output Process) / LCDC is the Display Controller for the
ROCKCHIP series of SoCs which transfers the image data from a video memory
buffer to an external LCD interface.

Required properties:
- compatible: value should be one of the following
		"rockchip,rk3288-lcdc"; /* for RK3288 SoCs */
		"rockchip,rk3368-lcdc"; /* for RK3368 SoCs */
		"rockchip,rk322x-lcdc"; /* for RK322X SoCs */
- rockchip,prop: set the lcdc as primary or extend display.
- rochchip,pwr18: set the controller IO voltage,0 is 3.3v,1 is 1.8v.
- reg: physical base address and length of the LCDC registers set.
- interrupts: interrupt number to the cpu and interrupt proterties.
- pinctrl-names: must contain a "default" entry.
- pinctrl-0: pin control group to be used for this controller.
- pinctrl-1: pin control group to be used for gpio.
- clocks: must include clock specifiers corresponding to entries in the
         clock-names property.
- clock-names: list of clock names sorted in the same order as the clocks
               property..

Optional Properties:
- rockchip,debug: printk debug message.
- rockchip,mirror: the lcdc mirror function.
- lcd_en:lcd_en: contain power control for lcd.
	- rockchip,power_type: power type,GPIO or REGULATOR.
	- gpios: pin number for gpio.
	- rockchip,delay: delay time after set power.

Example:

SoC specific DT entry:
	lcdc1: lcdc@ff940000 {
		compatible = "rockchip,rk3288-lcdc";
		rockchip,prop = <PRMRY>;
		rochchip,pwr18 = <0>;
		reg = <0xff940000 0x10000>;
		interrupts = <GIC_SPI 16 IRQ_TYPE_LEVEL_HIGH>;
		pinctrl-names = "default", "gpio";
		pinctrl-0 = <&lcdc0_lcdc>;
		pinctrl-1 = <&lcdc0_gpio>;		
		status = "disabled";
		clocks = <&clk_gates15 7>, <&dclk_lcdc1>, <&clk_gates15 8>, <&pd_vop1>;
		clock-names = "aclk_lcdc", "dclk_lcdc", "hclk_lcdc", "pd_lcdc";
	};


Board specific DT entry:

&lcdc1 {
	status = "okay";
	power_ctr: power_ctr {
		rockchip,debug = <0>;
		rockchip,mirror = <NO_MIRROR>;
		lcd_en:lcd_en {
			rockchip,power_type = <GPIO>;
			gpios = <&gpio7 GPIO_A3 GPIO_ACTIVE_HIGH>;
			rockchip,delay = <10>;
		};	
		lcd_cs:lcd_cs {
			rockchip,power_type = <GPIO>;
			gpios = <&gpio7 GPIO_A4 GPIO_ACTIVE_HIGH>;
			rockchip,delay = <10>;
		};
	};
};