Maxim MAX77686 multi-function device

MAX77686 is a Mulitifunction device with PMIC, RTC and Charger on chip. It is
interfaced to host controller using i2c interface. PMIC and Charger submodules
are addressed using same i2c slave address whereas RTC submodule uses different
i2c slave address,presently for which we are statically creating i2c client
while probing.This document describes the binding for mfd device and PMIC
submodule.

Required properties:
- compatible : Must be "maxim,max77686";
- reg : Specifies the i2c slave address of PMIC block.
- interrupts : This i2c device has an IRQ line connected to the main SoC.
- interrupt-parent : The parent interrupt controller.

Optional node:
- voltage-regulators : The regulators of max77686 have to be instantiated
  under subnode named "voltage-regulators" using the following format.

	regulator_name {
		regulator-compatible = LDOn/BUCKn
		standard regulator constraints....
	};
	refer Documentation/devicetree/bindings/regulator/regulator.txt
- buck_ramp_delay : Ramp delay is the time to settle down after voltage change.
  In some hardware ramp_delay for BUCKs is a configurable parameter.
- reg_op_mode : The regulators of max77686 have various operating mode
  capabilities such as low power mode, standby mode (controlled by PWRREQ
  signal) etc. Check the regulator CTRL register for the bits setting these
  modes.
- max77686,enable-low-jitter : If present, bit 3 of the 32KHZ register will be
  set.  This enables low jitter mode which can offset flaky clock
  signals during updates of the RTC.
- max77686,disable-low-jitter : If present, bit 3 of the 32KHZ register
  will be cleared. If both enable and disable are present, then enable
  will be favored.  If neither are set, the register will not be modified.


The regulator-compatible property of regulator should initialized with
string to get matched with their hardware counterparts as follow:

	-LDOn 	:	for LDOs, where n can lie in range 1 to 26.
			example: LDO1, LDO2, LDO26.
	-BUCKn 	:	for BUCKs, where n can lie in range 1 to 9.
			example: BUCK1, BUCK5, BUCK9.

Example:

	max77686@09 {
		compatible = "maxim,max77686";
		interrupt-parent = <&wakeup_eint>;
		interrupts = <26 0>;
		reg = <0x09>;
		max77686,buck_ramp_delay = <1>;
		max77686,enable-low-jitter;

		voltage-regulators {
			ldo11_reg {
				regulator-compatible = "LDO11";
				regulator-name = "vdd_ldo11";
				regulator-min-microvolt = <1900000>;
				regulator-max-microvolt = <1900000>;
				regulator-always-on;
				reg_op_mode = <1>;
			};

			buck1_reg {
				regulator-compatible = "BUCK1";
				regulator-name = "vdd_mif";
				regulator-min-microvolt = <950000>;
				regulator-max-microvolt = <1300000>;
				regulator-always-on;
				regulator-boot-on;
				reg_op_mode = <1>;
			};
	}
