TI BQ24251 Battery Charger
=========================

This chip manages the charging of a Li-Ion battery and provides basic
information like whether a SDP, DCP, or DCD is providing external USB
power.

It doesn't report the voltage of the battery but it can be combined with
a simple voltage divider circuit and an external ADC to get this value.

              R1                 R2
     +------/\/\/\------+------/\/\/\------+
     |                  |                  |
    Vbat               Vadc               GND

Required Properties:
-------------------
- compatible: "ti,bq24251-charger"
- reg: This must be 0x6a
- stat-gpio: The gpio connected to the STAT pin [1]
- pg-gpio: The gpio connected to the PG_L pin [1]

Optional Properties:
-------------------
- battery-regulation-voltage: The battery regulation voltage in uV
- max-battery-regulation-voltage: Maximum battery regulation voltage settable through sysfs in uV
- charge-current: The charge current in uA
- term-current-sense-threshold: Termination current sense threshold in uA
- vindpm-threshold: Input Vin-dpm voltage in uV
- ovp-voltage: Over volt protection voltage in uV
- io-channels: The phandle + io-specifier pair of the ADC [2]
- upper-divider-ohm: The resistance of R1 in the divider circuit
- lower-divider-ohm: The resistance of R2 in the divider circuit
- safety-timer-time-limit: Stop charging if this time is exceeded
  (0: 0.75 hr  1: 6 hr (default)  2: 9 hr  3: disabled)

Note: If any voltage divider properties are specified, they all must be.

[1] See Documentation/devicetree/bindings/gpio/gpio.txt
[2] See Documentation/devicetree/bindings/iio/iio-bindings.txt

Example:

/* BQ24251RGE (Charger Chip) @ 0x6A */
bq24251rge@6a {
	compatible = "ti,bq24251-charger";
	reg = <0x6a>;
	stat-gpio = <&gpio4 21 GPIO_ACTIVE_HIGH>;
	pg-gpio = <&gpio4 22 GPIO_ACTIVE_LOW>;

	battery-regulation-voltage = <4200000>;
	max-battery-regulation-voltage = <4200000>;
	charge-current = <500000>;
	term-current-sense-threshold = <50000>;
	vindpm-threshold = <4360000>;
	ovp-voltage = <10500000>;

	io-channels = <&adc1 3>;
	upper-divider-ohm = 100000;
	lower-divider-ohm = 301000;
};