xref: /openbmc/linux/Documentation/devicetree/bindings/rtc/rtc-cmos.txt (revision 7f3650a0b6615f230d798f11c18ff032172a4045)
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