Kernel-3.10.0-957.el7_gpio-samsung

Samsung Exynos4 GPIO Controller

Required properties:

• compatible: Compatible property value should be “samsung,exynos4-gpio>”.

• reg: Physical base address of the controller and length of memory mapped
  region.

• #gpio-cells: Should be 4. The syntax of the gpio specifier used by client nodes
  should be the following with values derived from the SoC user manual.
  <[phandle of the gpio controller node]

  [pin number within the gpio controller]
  [mux function]
  [flags and pull up/down]
  [drive strength]>
  

  Values for gpio specifier:

  • Pin number: is a value between 0 to 7.
  • Flags and Pull Up/Down: 0 - Pull Up/Down Disabled.

                        1 - Pull Down Enabled.
                        3 - Pull Up Enabled.
      Bit 16 (0x00010000) - Input is active low.
    

  • Drive Strength: 0 - 1x,

                1 - 3x,
                2 - 2x,
                3 - 4x
    

• gpio-controller: Specifies that the node is a gpio controller.

• #address-cells: should be 1.

• #size-cells: should be 1.

Example:

gpa0: gpio-controller@11400000 {
    #address-cells = <1>;
    #size-cells = <1>;
    compatible = "samsung,exynos4-gpio";
    reg = <0x11400000 0x20>;
    #gpio-cells = <4>;
    gpio-controller;
};

Samsung S3C24XX GPIO Controller

Required properties:

• compatible: Compatible property value should be “samsung,s3c24xx-gpio”.

• reg: Physical base address of the controller and length of memory mapped
  region.

• #gpio-cells: Should be 3. The syntax of the gpio specifier used by client nodes
  should be the following with values derived from the SoC user manual.
  <[phandle of the gpio controller node]

  [pin number within the gpio controller]
  [mux function]
  [flags and pull up/down]
  

  Values for gpio specifier:

  • Pin number: depending on the controller a number from 0 up to 15.
  • Mux function: Depending on the SoC and the gpio bank the gpio can be set

              as input, output or a special function
    

  • Flags and Pull Up/Down: the values to use differ for the individual SoCs

                example S3C2416/S3C2450:
                        0 - Pull Up/Down Disabled.
                        1 - Pull Down Enabled.
                        2 - Pull Up Enabled.
      Bit 16 (0x00010000) - Input is active low.
    

    Consult the user manual for the correct values of Mux and Pull Up/Down.

• gpio-controller: Specifies that the node is a gpio controller.

• #address-cells: should be 1.

• #size-cells: should be 1.

Example:

gpa: gpio-controller@56000000 {
    #address-cells = <1>;
    #size-cells = <1>;
    compatible = "samsung,s3c24xx-gpio";
    reg = <0x56000000 0x10>;
    #gpio-cells = <3>;
    gpio-controller;
};