power: Add snapshot of STC311x FG driver

STC311x Fuel Gauge device

STC311x FG provides interface to clients to read properties related

to the battery. Its main function is to retrieve the State of Charge (SOC),

a 0-100 percentage representing the amount of charge left in the battery.

- compatible

	Usage:		Required

	Value:		<string>

	Definition:	Must be  "st,stc311x" for the driver.

- reg

	Usage:		Required

	Value:		<u32>

	Definition:	The device 7-bit I2C address.

- st,float-voltage-mv

	Usage:		Required

	Value type:	<u32> in mV.

	Definition:	Float Voltage in mV - the maximum voltage up to which

			the battery is charged.

- st,rsense-mohm

	Usage:		Required

	Value type:	<u32> in mohm.

	Definition:	Current sense resistance value.

- st,nom-capacity-mah

	Usage:		Required

	Value type:	<u32> in mah.

	Definition:	This specifies nominal capacity of battery.

- st,rbatt-mohm

	Usage:		Required

	Value type:	<u32> in mohm.

	Definition:	This specifies battery internal resistance.

- st,ocv-tbl

	Usage:		Required

	Value type:	<u16 array> in mV.

	Definition:	This specifies an array of battery open circuit voltages at

			different SOC points.

			SOC points: [0 3 6 10 15 20 25 30 40 50 60 65 70 80 90

					100].

- st,vmtemp-tbl

	Usage:		Required

	Value type:	<u16 array>

	Definition:	This specifies an array of VCNF compensation table at

			different temperatures.

- st,temp-tbl

	Usage:		Required

	Value type:	<s16 array in DeciDegC>

	Definition:	This specifies an array of temperature points used in

			vtemp table and adaptive capacity tables.

- st,cutoff-voltage-mv

	Usage:		Optional

	Value type:	<u32> in mV

	Definition:	This is the minimum allowed system voltage. The FG

			will report SOC = 0 at this volatge. This value is

			also used to configure alarm voltage threshold.

			If not specified default value is set to 3400mV.

- st,alarm-soc

	Usage:		Optional

	Value type:	<u32> in %

	Definition:	This is the alarm SOC threshold.

			If not specified default value is set to 10%.

- st,term-current-ma

	Usage:		Optional

	Value type:	<u32> in mA

	Definition:	This is the maximum current threshold limit used to

			decide end of charge.

			If not specified value is set to

- st,relax-current-ma

	Usage:		Optional

	Value type:	<u32> in mA

	Definition:	This is the current threshold to decide automatic mode

			switch between voltage and moxec mode.

			If not specified value is set to

- st,adaptive-capacity-tbl

	Usage:		Optional

	Value type:	<u16 array, each element is in 0.1%>

	Definition:	This table specifies capacity degradation with

			temperature.

- st,force-voltage-mode

	Usage:		Optional

	Value type:	Boolean

	Definition:	This is to force FG always in low power voltage mode.

Example:

	st-fg@70 {

		compatible = "st,stc3117";

		reg = <0x70>;

		st,rbatt-mohm = <210>;

		st,nom-capacity-mah = <1500>;

		st,rsense-mohm = <10>;

		st,float-voltage-mv = <4200>;

		st,alarm-soc = <10>;

		st,alarm-voltage-mv = <3400>;

		st,term-current-ma = <150>;

		st,relax-current-ma = <200>;

		st,adaptive-capacity-tbl = /bits/ 16 <0 0 0 5 13 42 71>;

		st,ocv-tbl = /bits/ 16 <3300 3528 3667 3731 3753 3765 3772

					3792 3827 3900 3929 3957 3513 4072

					4167>;

		st,vmtemp-tbl = /bits/ 16 <85 90 100 160 320 440 840>

		st,temp-tbl = /bits/ 16 <60 40 25 10 0 (-10) (-20)>;

	};