xref: /linux/Documentation/devicetree/bindings/rtc/rtc-cmos.txt (revision 3d3337de8900a199a7ab304f742a6ad2a973b9f4)
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  - interrupt-parent : interrupt source phandle.
11  - ctrl-reg : Contains the initial value of the control register also
12    called "Register B".
13  - freq-reg : Contains the initial value of the frequency register also
14    called "Regsiter A".
15
16"Register A" and "B" are usually initialized by the firmware (BIOS for
17instance). If this is not done, it can be performed by the driver.
18
19ISA Example:
20
21	rtc@70 {
22	         compatible = "motorola,mc146818";
23	         interrupts = <8 3>;
24	         interrupt-parent = <&ioapic1>;
25	         ctrl-reg = <2>;
26	         freq-reg = <0x26>;
27	         reg = <1 0x70 2>;
28	 };
29