linux-kernel - Re: [PATCH] arm64: dts: renesas: r9a08g045: Add OPP table

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Message-ID: <CAMuHMdXrkb4rZr1HZ0p1d1u7+NTcE9J6PVEnhrq9iHVzho1daw@mail.gmail.com>
Date: Tue, 18 Feb 2025 09:23:40 +0100
From: Geert Uytterhoeven <geert@...ux-m68k.org>
To: Claudiu <claudiu.beznea@...on.dev>
Cc: magnus.damm@...il.com, robh@...nel.org, krzk+dt@...nel.org, 
	conor+dt@...nel.org, linux-renesas-soc@...r.kernel.org, 
	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org, 
	Claudiu Beznea <claudiu.beznea.uj@...renesas.com>, Lukasz Luba <lukasz.luba@....com>, 
	"Rafael J. Wysocki" <rafael@...nel.org>, Linux PM list <linux-pm@...r.kernel.org>
Subject: Re: [PATCH] arm64: dts: renesas: r9a08g045: Add OPP table

On Thu, 6 Feb 2025 at 09:26, Geert Uytterhoeven <geert@...ux-m68k.org> wrote:
> CC Energy Model
>
> On Tue, 28 Jan 2025 at 15:56, Claudiu <claudiu.beznea@...on.dev> wrote:
> > From: Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
> >
> > Add OPP table for the Renesas RZ/G3S SoC.
> >
> > Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
>
> Thanks for your patch!
>
> > --- a/arch/arm64/boot/dts/renesas/r9a08g045.dtsi
> > +++ b/arch/arm64/boot/dts/renesas/r9a08g045.dtsi
> > @@ -28,6 +28,33 @@ audio_clk2: audio2-clk {
> >                 clock-frequency = <0>;
> >         };
> >
> > +       cluster0_opp: opp-table-0 {
> > +               compatible = "operating-points-v2";
> > +               opp-shared;
> > +
> > +               opp-137500000 {
> > +                       opp-hz = /bits/ 64 <137500000>;
> > +                       opp-microvolt = <940000>;
> > +                       clock-latency-ns = <300000>;
> > +               };
> > +               opp-275000000 {
> > +                       opp-hz = /bits/ 64 <275000000>;
> > +                       opp-microvolt = <940000>;
> > +                       clock-latency-ns = <300000>;
> > +               };
> > +               opp-550000000 {
> > +                       opp-hz = /bits/ 64 <550000000>;
> > +                       opp-microvolt = <940000>;
> > +                       clock-latency-ns = <300000>;
> > +               };
> > +               opp-1100000000 {
> > +                       opp-hz = /bits/ 64 <1100000000>;
> > +                       opp-microvolt = <940000>;
> > +                       clock-latency-ns = <300000>;
> > +                       opp-suspend;
> > +               };
>
> So all voltages are the same.  This means the Energy Model (if enabled)
> will always pick the operating point with the highest clock rate, just
> like on R-Car E3 and RZ/G2E.  Apparently that can be fixed by using
> "opp-microwatt" instead, but I am still waiting for feedback about
> some practical points[1] (yes, the Ebisu-4D is still on my desk for
> this reason, and thus unavailable for remote access).

Reviewed-by: Geert Uytterhoeven <geert+renesas@...der.be>
i.e. will queue in renesas-devel for v6.15.

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds