Re: [PATCH 2/2] arm64: dts: qcom: sm7225-fairphone-fp4: Add PM6150L thermals

[Konrad Dybcio]

On 1/9/24 12:24, Luca Weiss wrote:
> On Tue Jan 9, 2024 at 11:09 AM CET, Konrad Dybcio wrote:
> > On 1/5/24 15:54, Luca Weiss wrote:
> > > Configure the thermals for the PA_THERM1, MSM_THERM, PA_THERM0,
> > > RFC_CAM_THERM, CAM_FLASH_THERM and QUIET_THERM thermistors connected to
> > > PM6150L.
> > >
> > > Due to hardware constraints we can only register 4 zones with
> > > pm6150l_adc_tm, the other 2 we can register via generic-adc-thermal.
> >
> > Ugh.. so the ADC can support more inputs than the ADC_TM that was
> > designed to ship alongside it can?
> >
> > And that's why the "generic-adc-thermal"-provided zones need to
> > be polled?
>
> This part of the code from qcom-spmi-adc-tm5.c was trigerring if I
> define more than 4 channels, and looking at downstream I can also see
> that only 4 zones are registered properly with adc_tm, the rest is
> registered with "qcom,adc-tm5-iio" which skips from what I could tell
> basically all the HW bits and only registering the thermal zone.
>
>
> 	ret = adc_tm5_read(chip, ADC_TM5_NUM_BTM,
> 			   &channels_available, sizeof(channels_available));
> 	if (ret) {
> 		dev_err(chip->dev, "read failed for BTM channels\n");
> 		return ret;
> 	}
>
> 	for (i = 0; i < chip->nchannels; i++) {
> 		if (chip->channels[i].channel >= channels_available) {
> 			dev_err(chip->dev, "Invalid channel %d\n", chip->channels[i].channel);
> 			return -EINVAL;
> 		}
> 	}
>
>
> > > The trip points can really only be considered as placeholders, more
> > > configuration with cooling etc. can be added later.
> > >
> > > Signed-off-by: Luca Weiss <luca.weiss@xxxxxxxxxxxxx>
> > > ---
> > [...]
> >
> > I've read the sentence above, but..
> > > +		sdm-skin-thermal {
> > > +			polling-delay-passive = <1000>;
> > > +			polling-delay = <5000>;
> > > +			thermal-sensors = <&msm_therm_sensor>;
> > > +
> > > +			trips {
> > > +				active-config0 {
> > > +					temperature = <125000>;
> > > +					hysteresis = <1000>;
> > > +					type = "passive";
> >
> > I don't fancy burnt fingers for dinner!
>
> With passive trip point it wouldn't even do anything now, but at what
> temp do you think it should do what? I'd definitely need more time to
> understand more of how the thermal setup works in downstream Android,
> and then replicate a sane configuration for mainline with proper
> temperatures, cooling, etc.
If "skin therm" means "the temperature of some part of the phone's
body that can be felt with a human hand", then definitely some
throttling should happen at 40ish with heavy throttling at 50
and crit at 55 or so..

We should probably make this a broader topic and keep a single
policy for all supported phones.

+ CC AGdR, may be interested in where this leads

Konrad