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     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         };
Cache object: e6604f894995088863491aa6cdc52cf0 
 
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