xref: /linux/Documentation/devicetree/bindings/rtc/rtc-cmos.txt (revision d7bd0aeb5ab6609b71ca87db4ec6d8bba24b2209)
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