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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 [pull up/down]
15 [drive strength]>
16
17 Values for gpio specifier:
18 - Pin number: is a value between 0 to 7.
19 - Pull Up/Down: 0 - Pull Up/Down Disabled.
20 1 - Pull Down Enabled.
21 3 - Pull Up Enabled.
22 - Drive Strength: 0 - 1x,
23 1 - 3x,
24 2 - 2x,
25 3 - 4x
26
27- gpio-controller: Specifies that the node is a gpio controller.
28- #address-cells: should be 1.
29- #size-cells: should be 1.
30
31Example:
32
33 gpa0: gpio-controller@11400000 {
34 #address-cells = <1>;
35 #size-cells = <1>;
36 compatible = "samsung,exynos4-gpio";
37 reg = <0x11400000 0x20>;
38 #gpio-cells = <4>;
39 gpio-controller;
40 };