linux-kernel - RE: [PATCH V3 3/3] arm64: dts: imx8mp: Add thermal zones support

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Message-ID: <DB3PR0402MB391651B42ABEBCF29F8AB4E3F5C70@DB3PR0402MB3916.eurprd04.prod.outlook.com>
Date:   Fri, 3 Apr 2020 06:04:28 +0000
From:   Anson Huang <anson.huang@....com>
To:     Amit Kucheria <amit.kucheria@...durent.com>
CC:     Zhang Rui <rui.zhang@...el.com>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        Shawn Guo <shawnguo@...nel.org>,
        Sascha Hauer <s.hauer@...gutronix.de>,
        "kernel@...gutronix.de" <kernel@...gutronix.de>,
        Fabio Estevam <festevam@...il.com>,
        Horia Geanta <horia.geanta@....com>,
        Peng Fan <peng.fan@....com>,
        Linux PM list <linux-pm@...r.kernel.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@...r.kernel.org>,
        lakml <linux-arm-kernel@...ts.infradead.org>,
        LKML <linux-kernel@...r.kernel.org>,
        dl-linux-imx <linux-imx@....com>
Subject: RE: [PATCH V3 3/3] arm64: dts: imx8mp: Add thermal zones support

Hi, Amit

> Subject: Re: [PATCH V3 3/3] arm64: dts: imx8mp: Add thermal zones support
> 
> On Fri, Apr 3, 2020 at 9:04 AM Anson Huang <anson.huang@....com> wrote:
> >
> > Hi, Amit
> >
> > > Subject: Re: [PATCH V3 3/3] arm64: dts: imx8mp: Add thermal zones
> > > support
> > >
> > > On Mon, Mar 23, 2020 at 6:05 PM Anson Huang
> <Anson.Huang@....com>
> > > wrote:
> > > >
> > > > i.MX8MP has a TMU inside which supports two thermal zones, add
> > > > support for them.
> > > >
> > > > Signed-off-by: Anson Huang <Anson.Huang@....com>
> > >
> > >
> > > [snip]
> > >
> > > >
> > > > +       thermal-zones {
> > > > +               cpu-thermal {
> > > > +                       polling-delay-passive = <250>;
> > > > +                       polling-delay = <2000>;
> > > > +                       thermal-sensors = <&tmu 0x0>;
> > >
> > > No need for 0x0, just use 0
> >
> > OK.
> >
> > >
> > > > +                       trips {
> > > > +                               cpu_alert0: trip0 {
> > > > +                                       temperature = <85000>;
> > > > +                                       hysteresis = <2000>;
> > > > +                                       type = "passive";
> > > > +                               };
> > > > +
> > > > +                               cpu_crit0: trip1 {
> > > > +                                       temperature = <95000>;
> > > > +                                       hysteresis = <2000>;
> > > > +                                       type = "critical";
> > > > +                               };
> > > > +                       };
> > > > +
> > > > +                       cooling-maps {
> > > > +                               map0 {
> > > > +                                       trip = <&cpu_alert0>;
> > > > +                                       cooling-device =
> > > > +                                               <&A53_0
> > > THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> > > > +                                               <&A53_1
> > > THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> > > > +                                               <&A53_2
> > > THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> > > > +                                               <&A53_3
> > > THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;
> > > > +                               };
> > > > +                       };
> > > > +               };
> > > > +
> > > > +               soc-thermal {
> > > > +                       polling-delay-passive = <250>;
> > > > +                       polling-delay = <2000>;
> > > > +                       thermal-sensors = <&tmu 0x1>;
> > >
> > > No need for 0x1, just use 1
> >
> > OK.
> >
> > >
> > > > +                       trips {
> > > > +                               soc_alert0: trip0 {
> > > > +                                       temperature = <85000>;
> > > > +                                       hysteresis = <2000>;
> > > > +                                       type = "passive";
> > > > +                               };
> > > > +
> > > > +                               soc_crit0: trip1 {
> > > > +                                       temperature = <95000>;
> > > > +                                       hysteresis = <2000>;
> > > > +                                       type = "critical";
> > > > +                               };
> > > > +                       };
> > >
> > > You need a cooling-map here since you have a passive trip point.
> >
> > Currently, there is no cooling map defined for soc thermal zone, the
> > cpufreq cooling is mapped to cpu thermal zone already, so do you think
> > it is OK to leave it as no cooling map, or it is better to put cpufreq cooling for
> soc thermal zone as well?
> >
> 
> If there is no cooling, why do you need a passive trip point? Just make it a hot
> trip that will send you a nofication (if .notify callback registered).

OK, understood, I prefer to keep the passive trip point same as cpu thermal zone,
so I will also put the cpufreq cooling map for soc thermal zone.

Thanks,
Anson