162306a36Sopenharmony_ci Motorola mc146818 compatible RTC 262306a36Sopenharmony_ci~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 362306a36Sopenharmony_ci 462306a36Sopenharmony_ciRequired properties: 562306a36Sopenharmony_ci - compatible : "motorola,mc146818" 662306a36Sopenharmony_ci - reg : should contain registers location and length. 762306a36Sopenharmony_ci 862306a36Sopenharmony_ciOptional properties: 962306a36Sopenharmony_ci - interrupts : should contain interrupt. 1062306a36Sopenharmony_ci - ctrl-reg : Contains the initial value of the control register also 1162306a36Sopenharmony_ci called "Register B". 1262306a36Sopenharmony_ci - freq-reg : Contains the initial value of the frequency register also 1362306a36Sopenharmony_ci called "Register A". 1462306a36Sopenharmony_ci 1562306a36Sopenharmony_ci"Register A" and "B" are usually initialized by the firmware (BIOS for 1662306a36Sopenharmony_ciinstance). If this is not done, it can be performed by the driver. 1762306a36Sopenharmony_ci 1862306a36Sopenharmony_ciISA Example: 1962306a36Sopenharmony_ci 2062306a36Sopenharmony_ci rtc@70 { 2162306a36Sopenharmony_ci compatible = "motorola,mc146818"; 2262306a36Sopenharmony_ci interrupts = <8 3>; 2362306a36Sopenharmony_ci interrupt-parent = <&ioapic1>; 2462306a36Sopenharmony_ci ctrl-reg = <2>; 2562306a36Sopenharmony_ci freq-reg = <0x26>; 2662306a36Sopenharmony_ci reg = <1 0x70 2>; 2762306a36Sopenharmony_ci }; 28