linux/Documentation/devicetree/bindings/gpio/gpio-samsung.txt
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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      [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
  43
  44Samsung S3C24XX GPIO Controller
  45
  46Required properties:
  47- compatible: Compatible property value should be "samsung,s3c24xx-gpio".
  48
  49- reg: Physical base address of the controller and length of memory mapped
  50  region.
  51
  52- #gpio-cells: Should be 3. The syntax of the gpio specifier used by client nodes
  53  should be the following with values derived from the SoC user manual.
  54     <[phandle of the gpio controller node]
  55      [pin number within the gpio controller]
  56      [mux function]
  57      [flags and pull up/down]
  58
  59  Values for gpio specifier:
  60  - Pin number: depending on the controller a number from 0 up to 15.
  61  - Mux function: Depending on the SoC and the gpio bank the gpio can be set
  62                  as input, output or a special function
  63  - Flags and Pull Up/Down: the values to use differ for the individual SoCs
  64                    example S3C2416/S3C2450:
  65                            0 - Pull Up/Down Disabled.
  66                            1 - Pull Down Enabled.
  67                            2 - Pull Up Enabled.
  68          Bit 16 (0x00010000) - Input is active low.
  69  Consult the user manual for the correct values of Mux and Pull Up/Down.
  70
  71- gpio-controller: Specifies that the node is a gpio controller.
  72- #address-cells: should be 1.
  73- #size-cells: should be 1.
  74
  75Example:
  76
  77        gpa: gpio-controller@56000000 {
  78                #address-cells = <1>;
  79                #size-cells = <1>;
  80                compatible = "samsung,s3c24xx-gpio";
  81                reg = <0x56000000 0x10>;
  82                #gpio-cells = <3>;
  83                gpio-controller;
  84        };
  85