xref: /linux/Documentation/devicetree/bindings/rtc/rtc-cmos.txt (revision 4dc44aec28c8ecc6744d02c8d7d68bf0a8d59891)
1 Motorola mc146818 compatible RTC
2~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
3
4Required properties:
5  - compatible : "motorola,mc146818"
6  - reg : should contain registers location and length.
7
8Optional properties:
9  - interrupts : should contain interrupt.
10  - ctrl-reg : Contains the initial value of the control register also
11    called "Register B".
12  - freq-reg : Contains the initial value of the frequency register also
13    called "Register A".
14
15"Register A" and "B" are usually initialized by the firmware (BIOS for
16instance). If this is not done, it can be performed by the driver.
17
18ISA Example:
19
20	rtc@70 {
21	         compatible = "motorola,mc146818";
22	         interrupts = <8 3>;
23	         interrupt-parent = <&ioapic1>;
24	         ctrl-reg = <2>;
25	         freq-reg = <0x26>;
26	         reg = <1 0x70 2>;
27	 };
28