Pincontrol driver for MAX77620 Power management IC from Maxim Semiconductor.

Device has 8 GPIO pins which can be configured as GPIO as well as the
special IO functions.

Please refer file <devicetree/bindings/pinctrl/pinctrl-bindings.txt>
for details of the common pinctrl bindings used by client devices,
including the meaning of the phrase "pin configuration node".

Optional Pinmux properties:
--------------------------
Following properties are required if default setting of pins are required
at boot.
- pinctrl-names: A pinctrl state named per <pinctrl-bindings.txt>.
- pinctrl[0...n]: Properties to contain the phandle for pinctrl states per
		<pinctrl-bindings.txt>.

The pin configurations are defined as child of the pinctrl states node. Each
sub-node have following properties:

Required properties:
------------------
- pins: List of pins. Valid values of pins properties are:
		      gpio0, gpio1, gpio2, gpio3, gpio4, gpio5, gpio6, gpio7.

Optional properties:
-------------------
Following are optional properties defined as pinmux DT binding document
<pinctrl-bindings.txt>. Absence of properties will leave the configuration
on default.
	function,
	drive-push-pull,
	drive-open-drain,
	bias-pull-up,
	bias-pull-down.

Valid values for function properties are:
	gpio, lpm-control-in, fps-out, 32k-out, sd0-dvs-in, sd1-dvs-in,
	reference-out

Theres is also customised properties for the GPIO1, GPIO2 and GPIO3. These
customised properties are required to configure FPS configuration parameters
of these GPIOs. Please refer <devicetree/bindings/mfd/max77620.txt> for more
detail of Flexible Power Sequence (FPS).

- maxim,active-fps-source:		FPS source for the GPIOs to get
					enabled/disabled when system is in
					active state.  Valid values are:
					- MAX77620_FPS_SRC_0,
						FPS source is FPS0.
					- MAX77620_FPS_SRC_1,
						FPS source is FPS1
					- MAX77620_FPS_SRC_2 and
						FPS source is FPS2
					- MAX77620_FPS_SRC_NONE.
						GPIO is not controlled
						by FPS events and it gets
						enabled/disabled by register
						access.
					Absence of this property will leave
					the FPS configuration register for that
					GPIO to default configuration.

- maxim,active-fps-power-up-slot:	Sequencing event slot number on which
					the GPIO get enabled when
					master FPS input event set to HIGH.
					Valid values are 0 to 7.
					This is applicable if FPS source is
					selected as FPS0, FPS1 or FPS2.

- maxim,active-fps-power-down-slot:	Sequencing event slot number on which
					the GPIO get disabled when master
					FPS input event set to LOW.
					Valid values are 0 to 7.
					This is applicable if FPS source is
					selected as FPS0, FPS1 or FPS2.

- maxim,suspend-fps-source:		This is same as property
					"maxim,active-fps-source" but value
					get configured when system enters in
					to suspend state.

- maxim,suspend-fps-power-up-slot:	This is same as property
					"maxim,active-fps-power-up-slot" but
					this value get configured into FPS
					configuration register when system
					enters into suspend.
					This is applicable if suspend state
					FPS source is selected as FPS0, FPS1 or

- maxim,suspend-fps-power-down-slot:	This is same as property
					"maxim,active-fps-power-down-slot" but
					this value get configured into FPS
					configuration register when system
					enters into suspend.
					This is applicable if suspend state
					FPS source is selected as FPS0, FPS1 or
					FPS2.

Example:
--------
#include <dt-bindings/mfd/max77620.h>
...
max77620@3c {

	pinctrl-names = "default";
	pinctrl-0 = <&spmic_default>;

	spmic_default: pinmux@0 {
		pin_gpio0 {
			pins = "gpio0";
			function = "gpio";
		};

		pin_gpio1 {
			pins = "gpio1";
			function = "fps-out";
			maxim,active-fps-source = <MAX77620_FPS_SRC_0>;
		};

		pin_gpio2 {
			pins = "gpio2";
			function = "fps-out";
			maxim,active-fps-source = <MAX77620_FPS_SRC_1>;
		};
	};
};