Samsung Exynos4 GPIO Controller
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Required properties:
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- compatible: Compatible property value should be "samsung,exynos4-gpio>".
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- reg: Physical base address of the controller and length of memory mapped
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region.
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- #gpio-cells: Should be 4. The syntax of the gpio specifier used by client nodes
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should be the following with values derived from the SoC user manual.
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<[phandle of the gpio controller node]
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[pin number within the gpio controller]
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[mux function]
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[flags and pull up/down]
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[drive strength]>
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Values for gpio specifier:
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- Pin number: is a value between 0 to 7.
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- Flags and Pull Up/Down: 0 - Pull Up/Down Disabled.
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1 - Pull Down Enabled.
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3 - Pull Up Enabled.
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Bit 16 (0x00010000) - Input is active low.
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- Drive Strength: 0 - 1x,
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1 - 3x,
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2 - 2x,
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3 - 4x
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- gpio-controller: Specifies that the node is a gpio controller.
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- #address-cells: should be 1.
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- #size-cells: should be 1.
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Example:
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gpa0: gpio-controller@11400000 {
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#address-cells = <1>;
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#size-cells = <1>;
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compatible = "samsung,exynos4-gpio";
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reg = <0x11400000 0x20>;
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#gpio-cells = <4>;
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gpio-controller;
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};
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