Re: [PATCH] arm64: tegra: Enable built-in RTC on Jetson AGX Thor

[Thierry Reding <thierry.reding@kernel.org>]

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On Mon, Aug 17, 2026 at 03:41:31PM +0100, Jon Hunter wrote:
> 
> On 17/08/2026 15:32, Thierry Reding wrote:
> > From: Thierry Reding <treding@nvidia.com>
> > 
> > The built-in RTC is mostly useful for testing suspend/resume cycles.
> > 
> > Signed-off-by: Thierry Reding <treding@nvidia.com>
> > ---
> >   arch/arm64/boot/dts/nvidia/tegra264-p4071-0000+p3834.dtsi | 6 ++++++
> >   1 file changed, 6 insertions(+)
> > 
> > diff --git a/arch/arm64/boot/dts/nvidia/tegra264-p4071-0000+p3834.dtsi b/arch/arm64/boot/dts/nvidia/tegra264-p4071-0000+p3834.dtsi
> > index c4ba3322ed9a..113ecf297378 100644
> > --- a/arch/arm64/boot/dts/nvidia/tegra264-p4071-0000+p3834.dtsi
> > +++ b/arch/arm64/boot/dts/nvidia/tegra264-p4071-0000+p3834.dtsi
> > @@ -13,6 +13,12 @@ chosen {
> >   		stdout-path = "serial0:115200n8";
> >   	};
> > +	bus@0 {
> > +		rtc@c2c0000 {
> > +			status = "okay";
> > +		};
> > +	};
> > +
> 
> 
> Any reason we should not just enable in tegra264.dtsi by default? I see that
> we do that for tegra234.

This is more of a development type of option and not everybody may want
to have it enabled, especially since it's not always hooked up to do
anything useful. We commonly use it on the devkit for suspend/resume
testing, so it's useful there, but even then there's usually another RTC
on a PMIC or something that's considered the primary one.

So in production I suspect people may not want to enable the built-in
RTC. If we enabled it by default, then people would have to explicitly
disable it again.

I don't feel very strongly either way, and I could easily be swayed.

Thierry

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