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

[Geert Uytterhoeven]

Hi Marek,

On Wed, 6 Aug 2025 at 17:23, Marek Vasut <marek.vasut at 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.

Gr{oetje,eeting}s,

                        Geert

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