dt-bindings: power: supply: Add bindings for Microchip UCS1002

Add bindings for Microchip UCS1002 Programmable USB Port Power
Controller with Charger Emulation.
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Reviewed-by: Rob Herring <robh+dt@kernel.org>
Cc: Enric Balletbo Serra <enric.balletbo@collabora.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Fabio Estevam <festevam@gmail.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: linux-kernel@vger.kernel.org
Cc: linux-pm@vger.kernel.org
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

Documentation/devicetree/bindings/power/supply/microchip,ucs1002.txt

+Microchip UCS1002 USB Port Power Controller
+
+Required properties:
+- compatible		: Should be "microchip,ucs1002";
+- reg			: I2C slave address
+
+Optional properties:
+- interrupts		: A list of interrupts lines present (could be either
+			  corresponding to A_DET# pin, ALERT# pin, or both)
+- interrupt-names	: A list of interrupt names. Should contain (if
+			  present):
+			  - "a_det" for line connected to A_DET# pin
+			  - "alert" for line connected to ALERT# pin
+			  Both are expected to be IRQ_TYPE_EDGE_BOTH
+Example:
+
+&i2c3 {
+	charger@32 {
+		compatible = "microchip,ucs1002";
+		pinctrl-names = "default";
+		pinctrl-0 = <&pinctrl_ucs1002_pins>;
+		reg = <0x32>;
+		interrupts-extended = <&gpio5 2 IRQ_TYPE_EDGE_BOTH>,
+				      <&gpio3 21 IRQ_TYPE_EDGE_BOTH>;
+		interrupt-names = "a_det", "alert";
+	};
+};