|  Motorola mc146818 compatible RTC | 
 | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | 
 |  | 
 | Required properties: | 
 |   - compatible : "motorola,mc146818" | 
 |   - reg : should contain registers location and length. | 
 |  | 
 | Optional properties: | 
 |   - interrupts : should contain interrupt. | 
 |   - ctrl-reg : Contains the initial value of the control register also | 
 |     called "Register B". | 
 |   - freq-reg : Contains the initial value of the frequency register also | 
 |     called "Regsiter A". | 
 |  | 
 | "Register A" and "B" are usually initialized by the firmware (BIOS for | 
 | instance). If this is not done, it can be performed by the driver. | 
 |  | 
 | ISA Example: | 
 |  | 
 | 	rtc@70 { | 
 | 	         compatible = "motorola,mc146818"; | 
 | 	         interrupts = <8 3>; | 
 | 	         interrupt-parent = <&ioapic1>; | 
 | 	         ctrl-reg = <2>; | 
 | 	         freq-reg = <0x26>; | 
 | 	         reg = <1 0x70 2>; | 
 | 	 }; |