* Device tree bindings for Nokia Retu and Tahvo multi-function device

Retu and Tahvo are a multi-function devices found on Nokia Internet
Tablets (770, N800 and N810). The Retu chip provides watchdog timer
and power button control functionalities while Tahvo chip provides
USB transceiver functionality.

Required properties:
- compatible:		"nokia,retu" or "nokia,tahvo"
- reg:			Specifies the CBUS slave address of the ASIC chip
- interrupts: 		The interrupt line the device is connected to
- interrupt-parent:	The parent interrupt controller

Example:

cbus0 {
	compatible = "i2c-cbus-gpio";
	...
	retu: retu@1 {
		compatible = "nokia,retu";
		interrupt-parent = <&gpio4>;
		interrupts = <12 IRQ_TYPE_EDGE_RISING>;
		reg = <0x1>;
	};
};