xref: /linux/Documentation/devicetree/bindings/rtc/rtc-cmos.txt (revision 0883c2c06fb5bcf5b9e008270827e63c09a88c1e)
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