Re: [PATCH v3 02/21] arm64: dts: qcom: msm8939: correct sleep clock frequency

[Dmitry Baryshkov]

On Mon, 30 Dec 2024 at 11:49, Bryan O'Donoghue
<bryan.odonoghue@xxxxxxxxxx> wrote:
>
> On 24/12/2024 10:17, Dmitry Baryshkov wrote:
> > The MSM8939 platform uses PM8916 to provide sleep clock. According to the
> > documentation, that clock has 32.7645 kHz frequency. Correct the sleep
> > clock definition.
> >
> > Fixes: 61550c6c156c ("arm64: dts: qcom: Add msm8939 SoC")
> > Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
> > ---
> >   arch/arm64/boot/dts/qcom/msm8939.dtsi | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/arch/arm64/boot/dts/qcom/msm8939.dtsi b/arch/arm64/boot/dts/qcom/msm8939.dtsi
> > index 7a6f1eeaa3fc438f7b6c1d3b2dd17fb1b6f81d9a..7cd5660de1b33def5b9dc8a0d02583c3eaffb17f 100644
> > --- a/arch/arm64/boot/dts/qcom/msm8939.dtsi
> > +++ b/arch/arm64/boot/dts/qcom/msm8939.dtsi
> > @@ -34,7 +34,7 @@ xo_board: xo-board {
> >               sleep_clk: sleep-clk {
> >                       compatible = "fixed-clock";
> >                       #clock-cells = <0>;
> > -                     clock-frequency = <32768>;
> > +                     clock-frequency = <32764>;
> >               };
> >       };
> >
> >
>
> Here's a quote from "MSM8936/MSM8939 Clock Plan"
> Section 2.1:
>
> "The chip does not have a separate sleep crystal. The sleep clock, whose
> oscillation frequency is 32.768 kHz, used as the source for timetick is
> generated from XO using a divisor of 586."

19200000 / 586 = 32764.5


-- 
With best wishes
Dmitry