Device-Tree bindings for Samsung Exynos7 SoC display controller (DECON)

DECON (Display and Enhancement Controller) is the Display Controller for the
Exynos7 series of SoCs which transfers the image data from a video memory
buffer to an external LCD interface.

Required properties:
- compatible: value should be "samsung,exynos7-decon";

- reg: physical base address and length of the DECON registers set.

- interrupt-parent: should be the phandle of the decon controller's
		parent interrupt controller.

- interrupts: should contain a list of all DECON IP block interrupts in the
		 order: FIFO Level, VSYNC, LCD_SYSTEM. The interrupt specifier
		 format depends on the interrupt controller used.

- interrupt-names: should contain the interrupt names: "fifo", "vsync",
	"lcd_sys", in the same order as they were listed in the interrupts
        property.

- pinctrl-0: pin control group to be used for this controller.

- pinctrl-names: must contain a "default" entry.

- 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. Must contain "pclk_decon0", "aclk_decon0",
	       "decon0_eclk", "decon0_vclk".
- i80-if-timings: timing configuration for lcd i80 interface support.

Optional Properties:
- power-domains: a phandle to DECON power domain node.
- display-timings: timing settings for DECON, as described in document [1].
		Can be used in case timings cannot be provided otherwise
		or to override timings provided by the panel.

[1]: Documentation/devicetree/bindings/display/panel/display-timing.txt

Example:

SoC specific DT entry:

	decon@13930000 {
		compatible = "samsung,exynos7-decon";
		interrupt-parent = <&combiner>;
		reg = <0x13930000 0x1000>;
		interrupt-names = "lcd_sys", "vsync", "fifo";
		interrupts = <0 188 0>, <0 189 0>, <0 190 0>;
		clocks = <&clock_disp PCLK_DECON_INT>,
			 <&clock_disp ACLK_DECON_INT>,
			 <&clock_disp SCLK_DECON_INT_ECLK>,
			 <&clock_disp SCLK_DECON_INT_EXTCLKPLL>;
		clock-names = "pclk_decon0", "aclk_decon0", "decon0_eclk",
				"decon0_vclk";
		status = "disabled";
	};

Board specific DT entry:

	decon@13930000 {
		pinctrl-0 = <&lcd_clk &pwm1_out>;
		pinctrl-names = "default";
		status = "okay";
	};