Broadcom NSP (Northstar plus) IOMUX Controller

The NSP IOMUX controller supports group based mux configuration. In
addition, certain pins can be muxed to GPIO function individually.

Required properties:
- compatible:
    Must be "brcm,nsp-pinmux"

- reg:
    Should contain the register physical address and length for each of
    GPIO_CONTROL0, GP_AUX_SEL and IPROC_CONFIG IOMUX registers

Properties in subnodes:
- function:
    The mux function to select

- groups:
    The list of groups to select with a given function

For more details, refer to
Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt

For example:

	pinmux: pinmux@1803f1c0 {
		compatible = "brcm,nsp-pinmux";
		reg = <0x1803f1c0 0x04>,
		      <0x18030028 0x04>,
		      <0x1803f408 0x04>;

		pinctrl-names = "default";
		pinctrl-0 = <&pwm &gpio_b &nand_sel>;

		pwm: pwm {
			function = "pwm";
			groups = "pwm0_grp", "pwm1_grp";
		};

		gpio_b: gpio_b {
			function = "gpio_b";
			groups = "gpio_b_0_grp", "gpio_b_1_grp";
		};

		nand_sel: nand_sel {
			function = "nand";
			groups = "nand_grp";
		};
	};

List of supported functions and groups in Northstar Plus:

"spi": "spi_grp"

"i2c": "i2c_grp"

"mdio": "mdio_grp"

"pwm": "pwm0_grp", "pwm1_grp", "pwm2_grp", "pwm3_grp"

"gpio_b": "gpio_b_0_grp", "gpio_b_1_grp", "gpio_b_2_grp", "gpio_b_3_grp"

"uart1": "uart1_grp"

"uart2": "uart2_grp"

"synce": "synce_grp"

"sata_led_grps": "sata0_led_grp", "sata1_led_grp"

"xtal_out": "xtal_out_grp"

"sdio": "sdio_pwr_grp", "sdio_1p8v_grp"

"switch_led": "switch_p05_led0_grp", "switch_p05_led1_grp"

"nand": "nand_grp"

"emmc": "emmc_grp"