Documentation/devicetree/bindings/gpio/gpio-samsung.txt

   1 Samsung Exynos4 GPIO Controller
   2
   3 Required 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
  32 Example:
  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         };