1Samsung Exynos4 GPIO Controller
2
3Required properties:
4- compatible: Compatible property value should be "samsung,exynos4-gpio>".
5
6- reg: Physical base address of the controller and length of memory mapped
7  region.
8
9- #gpio-cells: Should be 4. The syntax of the gpio specifier used by client nodes
10  should be the following with values derived from the SoC user manual.
11     <[phandle of the gpio controller node]
12      [pin number within the gpio controller]
13      [mux function]
14      [flags and pull up/down]
15      [drive strength]>
16
17  Values for gpio specifier:
18  - Pin number: is a value between 0 to 7.
19  - Flags and Pull Up/Down: 0 - Pull Up/Down Disabled.
20                            1 - Pull Down Enabled.
21                            3 - Pull Up Enabled.
22          Bit 16 (0x00010000) - Input is active low.
23  - Drive Strength: 0 - 1x,
24                    1 - 3x,
25                    2 - 2x,
26                    3 - 4x
27
28- gpio-controller: Specifies that the node is a gpio controller.
29- #address-cells: should be 1.
30- #size-cells: should be 1.
31
32Example:
33
34	gpa0: gpio-controller@11400000 {
35		#address-cells = <1>;
36		#size-cells = <1>;
37		compatible = "samsung,exynos4-gpio";
38		reg = <0x11400000 0x20>;
39		#gpio-cells = <4>;
40		gpio-controller;
41	};
42