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-binding.txt>.
- pinctrl[0...n]: Properties to contain the phandle for pinctrl states per
		<pinctrl-binding.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.

There is anothe name of these properties to reduce the property name
length to meet ePAPR specs. The another name is without vendor as
follows:
	maxim,active-fps-source -> active-fps-source
	maxim,active-fps-power-up-slot -> active-fps-power-up-slot
	maxim,active-fps-power-down-slot -> active-fps-power-down-slot
	maxim,suspend-fps-source -> suspend-fps-source
	maxim,suspend-fps-power-up-slot -> suspend-fps-power-up-slot
	maxim,suspend-fps-power-down-slot -> suspend-fps-power-down-slot
	maxim,ramp-rate-setting -> ramp-rate-setting
	maxim,power-ok-control -> power-ok-control

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>;
		};
	};
};