Re: [PATCH] arm64: dts: renesas: r8a779g3: Update thermal trip points on V4H Sparrow Hawk

[Geert Uytterhoeven <geert@linux-m68k.org>]

Hi Marek,

On Fri, 15 Aug 2025 at 01:36, Marek Vasut <marek.vasut@mailbox.org> wrote:
> On 8/14/25 5:50 PM, Geert Uytterhoeven wrote:
> > On Wed, 6 Aug 2025 at 17:23, Marek Vasut <marek.vasut@mailbox.org> wrote:
> >> On 8/6/25 11:35 AM, Geert Uytterhoeven wrote:
> >>>> +/* THS sensor in SoC near CA76 cores does more progressive cooling. */
> >>>> +&sensor_thermal_ca76 {
> >>>> +       critical-action = "shutdown";
> >>>> +
> >>>> +       cooling-maps {
> >>>> +               /*
> >>>> +                * The cooling-device minimum and maximum parameters inversely
> >>>> +                * match opp-table-0 {} node entries in r8a779g0.dtsi, in other
> >>>> +                * words, 0 refers to 1.8 GHz OPP and 4 refers to 500 MHz OPP.
> >>>> +                * This is because they refer to cooling levels, where maximum
> >>>> +                * cooling level happens at 500 MHz OPP, when the CPU core is
> >>>> +                * running slowly and therefore generates least heat.
> >>>
> >>> That applies to cooling-device = <&a76_[0-3] ...>...
> >>
> >> Do you want me to add this line into the comment ?
> >
> > I don't think that is really needed (see below)
> >
> >>>> +                */
> >>>> +               map0 {
> >>>> +                       /* At 68C, inhibit 1.7 GHz and 1.8 GHz modes */
> >>>> +                       trip = <&sensor3_passive_low>;
> >>>> +                       cooling-device = <&a76_0 2 4>;
> >>>> +                       contribution = <128>;
> >>>> +               };
> >>>> +
> >>>> +               map1 {
> >>>> +                       /* At 72C, inhibit 1.5 GHz mode */
> >>>> +                       trip = <&sensor3_passive_mid>;
> >>>> +                       cooling-device = <&a76_0 3 4>;
> >>>> +                       contribution = <256>;
> >>>> +               };
> >>>> +
> >>>> +               map2 {
> >>>> +                       /* At 76C, start injecting idle states */
> >>>> +                       trip = <&sensor3_passive_hi>;
> >>>> +                       cooling-device = <&a76_0_thermal_idle 0 80>,
> >>>> +                                        <&a76_1_thermal_idle 0 80>,
> >>>> +                                        <&a76_2_thermal_idle 0 80>,
> >>>> +                                        <&a76_3_thermal_idle 0 80>;
> >>>
> >>> ... but what do "0 80" refer to? I couldn't find in the thermal-idle
> >>> bindings what exactly are the minimum and maximum cooling states here.
> >>
> >> The comments in drivers/thermal/cpuidle_cooling.c clarify that, it is
> >> the idle injection rate in percent, in this case the cooling can inject
> >> idle states up to 80% of time.
> >
> > OK, so I will add "(0-80%)" to the idle states comment, and sort
> > the nodes while queuing in renesas-devel for v6.18.
> I sent a V3 to make this more official. I hope that helps.

Thanks, I took v3 instead.

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-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