Atmel AT91RM9200 Real Time Clock

Required properties:
- compatible: should be: "atmel,at91rm9200-rtc" or "atmel,at91sam9x5-rtc"
- reg: physical base address of the controller and length of memory mapped
  region.
- interrupts: rtc alarm/event interrupt
- clocks: phandle to input clock.

Example:

rtc@fffffe00 {
	compatible = "atmel,at91rm9200-rtc";
	reg = <0xfffffe00 0x100>;
	interrupts = <1 4 7>;
	clocks = <&clk32k>;
};
