Re: [PATCH] arm64: dts: amlogic: odroid-go-ultra: use the RK818 RTC as rtc0

[Neil Armstrong]

Hi,

On 10/17/26 13:07, Shigeaki Asai wrote:
> The ODROID-GO Ultra has two PMICs with an RTC each, RK818 and RK817,
> and the SoC has the meson virtual RTC. Only vrtc has an alias, rtc0.
>
> An RTC without an alias takes the lowest free number, and the RK817
> RTC registers early, so it usually becomes rtc0, the RTC the system
> time is set from at boot. The RK817 RTC seems to run without a 32kHz
> crystal on this board: it ran about 1.5% fast while the board was on
> and 14-17% slow while it was off. The RK818 RTC keeps time well:
> with it as rtc0, the clock was off by less than a second after the
> board was off, with no charger connected, for 12 hours 40 minutes.
>
> Use the RK818 RTC as rtc0, and give the other two RTCs an alias as
> well, so that the numbering does not depend on probe order.
>
> Fixes: 62e73f000696 ("arm64: dts: amlogic: add initial Odroid Go Ultra DTS")
> Assisted-by: claude-opus-5-5
> Signed-off-by: Shigeaki Asai <y-asai.0816@xxxxxxxxxxxx>
> ---
>   arch/arm64/boot/dts/amlogic/meson-g12b-odroid-go-ultra.dts | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm64/boot/dts/amlogic/meson-g12b-odroid-go-ultra.dts b/arch/arm64/boot/dts/amlogic/meson-g12b-odroid-go-ultra.dts
> index 348baa4e6d84..86902f68d7d4 100644
> --- a/arch/arm64/boot/dts/amlogic/meson-g12b-odroid-go-ultra.dts
> +++ b/arch/arm64/boot/dts/amlogic/meson-g12b-odroid-go-ultra.dts
> @@ -18,7 +18,9 @@ / {
>   
>   	aliases {
>   		serial0 = &uart_AO;
> -		rtc0 = &vrtc;
> +		rtc0 = &rk818;
> +		rtc1 = &vrtc;
> +		rtc2 = &rk817;

The vrtc was used as rtc0 because it's the defaut wakeup rtc,
can the rk818 and rk817 wakeup the system when in system suspend ?

Neil

>   	};
>   
>   	adc-joystick-left {