linux-kernel - Re: [PATCH 4/4] arm64: dts: qcom: qcm6490-fairphone-fp5: Add PM7325 thermals

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Message-ID: <5ac0d16a-0303-46c7-a008-31280629cc11@linaro.org>
Date:   Wed, 18 Oct 2023 22:28:13 +0200
From:   Konrad Dybcio <konrad.dybcio@...aro.org>
To:     Luca Weiss <luca@...tu.xyz>, Luca Weiss <luca.weiss@...rphone.com>,
        Andy Gross <agross@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Jonathan Cameron <jic23@...nel.org>,
        Lars-Peter Clausen <lars@...afoo.de>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Conor Dooley <conor+dt@...nel.org>,
        ~postmarketos/upstreaming@...ts.sr.ht
Cc:     phone-devel@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-msm@...r.kernel.org, linux-iio@...r.kernel.org,
        devicetree@...r.kernel.org
Subject: Re: [PATCH 4/4] arm64: dts: qcom: qcm6490-fairphone-fp5: Add PM7325
 thermals



On 10/14/23 19:52, Luca Weiss wrote:
> On Samstag, 14. Oktober 2023 01:13:29 CEST Konrad Dybcio wrote:
>> On 13.10.2023 10:09, Luca Weiss wrote:
>>> Configure the thermals for the QUIET_THERM, CAM_FLASH_THERM, MSM_THERM
>>> and RFC_CAM_THERM thermistors connected to PM7325.
>>>
>>> With this PMIC the software communication to the ADC is going through
>>> PMK7325 (= PMK8350).
>>>
>>> Signed-off-by: Luca Weiss <luca.weiss@...rphone.com>
>>> ---
>>>
>>>   arch/arm64/boot/dts/qcom/qcm6490-fairphone-fp5.dts | 117
>>>   +++++++++++++++++++++ 1 file changed, 117 insertions(+)
>>>
>>> diff --git a/arch/arm64/boot/dts/qcom/qcm6490-fairphone-fp5.dts
>>> b/arch/arm64/boot/dts/qcom/qcm6490-fairphone-fp5.dts index
>>> 2c01f799a6b2..d0b1e4e507ff 100644
>>> --- a/arch/arm64/boot/dts/qcom/qcm6490-fairphone-fp5.dts
>>> +++ b/arch/arm64/boot/dts/qcom/qcm6490-fairphone-fp5.dts
>>> @@ -9,6 +9,7 @@
>>>
>>>   #define PM7250B_SID 8
>>>   #define PM7250B_SID1 9
>>>
>>> +#include <dt-bindings/iio/qcom,spmi-adc7-pm7325.h>
>>>
>>>   #include <dt-bindings/iio/qcom,spmi-adc7-pmk8350.h>
>>>   #include <dt-bindings/leds/common.h>
>>>   #include <dt-bindings/pinctrl/qcom,pmic-gpio.h>
>>>
>>> @@ -137,6 +138,20 @@ afvdd_2p8: regulator-afvdd-2p8 {
>>>
>>>   	};
>>>   	
>>>   	thermal-zones {
>>>
>>> +		camera-thermal {
>>> +			polling-delay-passive = <0>;
>>> +			polling-delay = <0>;
>>> +			thermal-sensors = <&pmk8350_adc_tm 2>;
>>> +
>>> +			trips {
>>> +				active-config0 {
>>> +					temperature = <125000>;
>>
>> are
>>
>>> +		rear-cam-thermal {
>>>
>>> +					temperature = <125000>;
>>
>> you
>>
>>> +		sdm-skin-thermal {
>>>
>>> +					temperature = <125000>;
>>
>> sure
>>
>> about these temps?
> 
> (email from my other address, quicker right now)
> 
> Well yes and no.
> 
> Yes as in those are the temps specified in downstream dtb.
> No as in I'm 99% sure there's user space with definitely lower threshold that
> actually does something in response to the temps.
> 
> I didn't look too much into this but does the kernel even do something when it
> hits one of these trip points? I assume when there's a cooling device thing
> specified then it can actually tell the driver to do something, but without
> (and most drivers don't support this?) I'm assuming the kernel can't do much
> anyways?
> 
> So e.g. when the temperature for the flash led is reached I'm assuming
> downstream (+Android) either dims the led or turns it off? But I'd have to dig
> quite a bit into the thermal setup there to check what it's really doing.
I think reaching "critical" shuts down the platform, unless something
registering the thermal zone explicitly overrides the behavior.

> 
> But for now I think it's okay to put this current thermal config into dts and
> we'll improve it later when 1. I understand more and 2. maybe some useful
> drivers support the cooling bits?
Yeah it's better than nothing, but ultimately we should probably move
the values that userspace daemon operates on here in the dt..

Konrad