dt-bindings: power: supply: New bindings for ltc3651-charger

ltc3651-charger

Required properties:

 - compatible: "lltc,ltc3651-charger"

 - lltc,acpr-gpios: Connect to ACPR output. See remark below.

Optional properties:

 - lltc,fault-gpios: Connect to FAULT output. See remark below.

 - lltc,chrg-gpios: Connect to CHRG output. See remark below.

The ltc3651 outputs are open-drain type and active low. The driver assumes the

GPIO reports "active" when the output is asserted, so if the pins have been

connected directly, the GPIO flags should be set to active low also.

The driver will attempt to aquire interrupts for all GPIOs to detect changes in

line state. If the system is not capabale of providing interrupts, the driver

cannot report changes and userspace will need to periodically read the sysfs

attributes to detect changes.

Example:

	charger: battery-charger {

		compatible = "lltc,ltc3651-charger";

		lltc,acpr-gpios = <&gpio0 68 GPIO_ACTIVE_LOW>;

		lltc,fault-gpios = <&gpio0 64 GPIO_ACTIVE_LOW>;

		lltc,chrg-gpios = <&gpio0 63 GPIO_ACTIVE_LOW>;

	};