xref: /openbmc/linux/Documentation/devicetree/bindings/rtc/rtc-cmos.txt (revision 5ef12cb4a3a78ffb331c03a795a15eea4ae35155)
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