Documentation: Update samsung-pinctrl device tree bindings documentation

- reg: Base address of the pin controller hardware module and length of

  the address space it occupies.

- interrupts: interrupt specifier for the controller. The format and value of

  the interrupt specifier depends on the interrupt parent for the controller.

- Pin banks as child nodes: Pin banks of the controller are represented by child

  nodes of the controller node. Bank name is taken from name of the node. Each

  bank node must contain following properties:

  - gpio-controller: identifies the node as a gpio controller and pin bank.

  - #gpio-cells: number of cells in GPIO specifier. Since the generic GPIO

    binding is used, the amount of cells must be specified as 2. See generic

    GPIO binding documentation for description of particular cells.

- Pin mux/config groups as child nodes: The pin mux (selecting pin function

  mode) and pin config (pull up/down, driver strength) settings are represented

A. External GPIO Interrupts: For supporting external gpio interrupts, the

   following properties should be specified in the pin-controller device node.

   - interrupt-parent: phandle of the interrupt parent to which the external

     GPIO interrupts are forwarded to.

   - interrupts: interrupt specifier for the controller. The format and value of

     the interrupt specifier depends on the interrupt parent for the controller.

   In addition, following properties must be present in node of every bank

   of pins supporting GPIO interrupts:

   - interrupt-controller: identifies the controller node as interrupt-parent.

   - #interrupt-cells: the value of this property should be 2.

     - First Cell: represents the external gpio interrupt number local to the

       found on Samsung Exynos4210 SoC.

   - interrupt-parent: phandle of the interrupt parent to which the external

     wakeup interrupts are forwarded to.

   - interrupts: interrupt used by multiplexed wakeup interrupts.

   In addition, following properties must be present in node of every bank

   of pins supporting wake-up interrupts:

   - interrupt-controller: identifies the node as interrupt-parent.

   - #interrupt-cells: the value of this property should be 2

     - First Cell: represents the external wakeup interrupt number local to

       - 4 = high level triggered

       - 8 = low level triggered

   Node of every bank of pins supporting direct wake-up interrupts (without

   multiplexing) must contain following properties:

   - interrupt-parent: phandle of the interrupt parent to which the external

     wakeup interrupts are forwarded to.

   - interrupts: interrupts of the interrupt parent which are used for external

     wakeup interrupts from pins of the bank, must contain interrupts for all

     pins of the bank.

Aliases:

All the pin controller nodes should be represented in the aliases node using

the following format 'pinctrl{n}' where n is a unique number for the alias.

Example: A pin-controller node with pin banks:

	pinctrl_0: pinctrl@11400000 {

		compatible = "samsung,pinctrl-exynos4210";

		reg = <0x11400000 0x1000>;

		interrupts = <0 47 0>;

		/* ... */

		/* Pin bank without external interrupts */

		gpy0: gpy0 {

			gpio-controller;

			#gpio-cells = <2>;

		};

		/* ... */

		/* Pin bank with external GPIO or muxed wake-up interrupts */

		gpj0: gpj0 {

			gpio-controller;

			#gpio-cells = <2>;

			interrupt-controller;

			#interrupt-cells = <2>;

		};

		/* ... */

		/* Pin bank with external direct wake-up interrupts */

		gpx0: gpx0 {

			gpio-controller;

			#gpio-cells = <2>;

			interrupt-controller;

			interrupt-parent = <&gic>;

			interrupts = <0 16 0>, <0 17 0>, <0 18 0>, <0 19 0>,

				     <0 20 0>, <0 21 0>, <0 22 0>, <0 23 0>;

			#interrupt-cells = <2>;

		};

		/* ... */

	};

Example 1: A pin-controller node with pin groups.

	pinctrl_0: pinctrl@11400000 {

		reg = <0x11400000 0x1000>;

		interrupts = <0 47 0>;

		/* ... */

		uart0_data: uart0-data {

			samsung,pins = "gpa0-0", "gpa0-1";

			samsung,pin-function = <2>;

	pinctrl_1: pinctrl@11000000 {

		compatible = "samsung,pinctrl-exynos4210";

		reg = <0x11000000 0x1000>;

		interrupts = <0 46 0>;

		interrupt-controller;

		#interrupt-cells = <2>;

		interrupts = <0 46 0>

		wakup_eint: wakeup-interrupt-controller {

		/* ... */

		wakeup-interrupt-controller {

			compatible = "samsung,exynos4210-wakeup-eint";

			interrupt-parent = <&gic>;

			interrupt-controller;

			#interrupt-cells = <2>;

			interrupts = <0 16 0>, <0 17 0>, <0 18 0>, <0 19 0>,

					<0 20 0>, <0 21 0>, <0 22 0>, <0 23 0>,

					<0 24 0>, <0 25 0>, <0 26 0>, <0 27 0>,

					<0 28 0>, <0 29 0>, <0 30 0>, <0 31 0>,

					<0 32 0>;

			interrupts = <0 32 0>;

		};

	};

	static int s3c24xx_serial_probe(struct platform_device *pdev) {

		struct pinctrl *pinctrl;

		...

		...

		/* ... */

		pinctrl = devm_pinctrl_get_select_default(&pdev->dev);

	}