| b.liu | e958203 | 2025-04-17 19:18:16 +0800 | [diff] [blame] | 1 | Motorola mc146818 compatible RTC |
| 2 | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
| 3 | |
| 4 | Required properties: |
| 5 | - compatible : "motorola,mc146818" |
| 6 | - reg : should contain registers location and length. |
| 7 | |
| 8 | Optional 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 "Regsiter A". |
| 14 | |
| 15 | "Register A" and "B" are usually initialized by the firmware (BIOS for |
| 16 | instance). If this is not done, it can be performed by the driver. |
| 17 | |
| 18 | ISA 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 | }; |