* Freescale MXS GPIO controller

The Freescale MXS GPIO controller is part of MXS PIN controller.  The
GPIOs are organized in port/bank.  Each port consists of 32 GPIOs.

As the GPIO controller is embedded in the PIN controller and all the
GPIO ports share the same IO space with PIN controller, the GPIO node
will be represented as sub-nodes of MXS pinctrl node.

Required properties for GPIO node:
- compatible : Should be "fsl,<soc>-gpio".  The supported SoCs include
  imx23 and imx28.
- interrupts : Should be the port interrupt shared by all 32 pins.
- gpio-controller : Marks the device node as a gpio controller.
- #gpio-cells : Should be two.  The first cell is the pin number and
  the second cell is used to specify optional parameters (currently
  unused).
- interrupt-controller: Marks the device node as an interrupt controller.
- #interrupt-cells : Should be 2.  The first cell is the GPIO number.
  The second cell bits[3:0] is used to specify trigger type and level flags:
      1 = low-to-high edge triggered.
      2 = high-to-low edge triggered.
      4 = active high level-sensitive.
      8 = active low level-sensitive.

Note: Each GPIO port should have an alias correctly numbered in "aliases"
node.

Examples:

aliases {
	gpio0 = &gpio0;
	gpio1 = &gpio1;
	gpio2 = &gpio2;
	gpio3 = &gpio3;
	gpio4 = &gpio4;
};

pinctrl@80018000 {
	compatible = "fsl,imx28-pinctrl", "simple-bus";
	reg = <0x80018000 2000>;

	gpio0: gpio@0 {
		compatible = "fsl,imx28-gpio";
		interrupts = <127>;
		gpio-controller;
		#gpio-cells = <2>;
		interrupt-controller;
		#interrupt-cells = <2>;
	};

	gpio1: gpio@1 {
		compatible = "fsl,imx28-gpio";
		interrupts = <126>;
		gpio-controller;
		#gpio-cells = <2>;
		interrupt-controller;
		#interrupt-cells = <2>;
	};

	gpio2: gpio@2 {
		compatible = "fsl,imx28-gpio";
		interrupts = <125>;
		gpio-controller;
		#gpio-cells = <2>;
		interrupt-controller;
		#interrupt-cells = <2>;
	};

	gpio3: gpio@3 {
		compatible = "fsl,imx28-gpio";
		interrupts = <124>;
		gpio-controller;
		#gpio-cells = <2>;
		interrupt-controller;
		#interrupt-cells = <2>;
	};

	gpio4: gpio@4 {
		compatible = "fsl,imx28-gpio";
		interrupts = <123>;
		gpio-controller;
		#gpio-cells = <2>;
		interrupt-controller;
		#interrupt-cells = <2>;
	};
};