linux-kernel - Re: [PATCH v7 4/4] thermal: mediatek: add another get

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Message-ID: <0b5e3a14-fd23-4646-d4cb-df255eb8fa20@baylibre.com>
Date:   Tue, 24 Jan 2023 23:27:40 +0100
From:   Amjad Ouled-Ameur <aouledameur@...libre.com>
To:     Daniel Lezcano <daniel.lezcano@...aro.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Amit Kucheria <amitk@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Zhang Rui <rui.zhang@...el.com>
Cc:     AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>,
        Fabien Parent <fparent@...libre.com>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Markus Schneider-Pargmann <msp@...libre.com>,
        linux-pm@...r.kernel.org, Rob Herring <robh@...nel.org>,
        Michael Kao <michael.kao@...iatek.com>,
        linux-kernel@...r.kernel.org, Hsin-Yi Wang <hsinyi@...omium.org>,
        linux-arm-kernel@...ts.infradead.org,
        linux-mediatek@...ts.infradead.org, devicetree@...r.kernel.org
Subject: Re: [PATCH v7 4/4] thermal: mediatek: add another get_temp ops for
 thermal sensors


On 1/24/23 18:55, Daniel Lezcano wrote:
> On 24/01/2023 18:46, Amjad Ouled-Ameur wrote:
>>
>> On 1/24/23 17:54, Daniel Lezcano wrote:
>>>
>>> Hi Amjad,
>>>
>>> On 24/01/2023 11:08, Amjad Ouled-Ameur wrote:
>>>
>>> [ ... ]
>>>
>>>>>>
>>>>>> IIUC, there is a sensor per couple of cores. 1 x 2Bigs, 1 x 2Bigs, 1 x 4 Little, right ?
>>>>>
>>>>> MT8365 SoC has 4 x A53 CPUs. The SoC has 4 thermal zones per sensor. Thermal zone 0 corresponds
>>>>>
>>>>> to all 4 x A53 CPUs, the other thermal zones (1, 2 and 3) has nothing to do with CPUs. The cooling device type
>>>>>
>>>>> used for CPUs is passive. FYI, thermal zones 1, 2 and 3 are present in the SoC for debug-purpose only, they are not supposed
>>>>>
>>>>> to be used for production.
>>>>>
>>>> After reconsidering the fact that zones 1, 2 and 3 are only used for dev/debug, it might be best to avo >
>>>> aggregation as you suggested, and keep only support for zone 0 in this driver. Thus I suggest I send a V8
>>>>
>>>> where I keep only below fixes for this patch if that's okay with you:
>>>>
>>>> - Define "raw_to_mcelsius" function pointer for "struct thermal_bank_cfg".
>>>>
>>>> - Fix "mtk_thermal" variable in mtk_read_temp().
>>>>
>>>> - Set "mt->raw_to_mcelsius" in probe().
>>>>
>>>>
>>>> For zones 1, 2 and 3 we can later add a different driver specific for dev/debug to probe them to
>>>>
>>>> avoid confusion.
>>>
>>> You can add them in the driver and in the device tree, but just add the cooling device for the thermal zone 0.
>>
>> Thermal zone 0 uses CPU{0..3} for passive cooling, in this case we should register cooling device with
>>
>> cpufreq_cooling_register() for each CPU right ?
>
> No, the OF code device tree does already that. You just have to register the different thermal zones.
>
> Do you have a pointer to a device tree for this board and the thermal setup ?

Sure, here is a dtsi for MT8365 SoC which contains thermal nodes [0].

[0]: https://lore.kernel.org/linux-arm-kernel/20220531135026.238475-17-fparent@baylibre.com/#Z31arch:arm64:boot:dts:mediatek:mt8365.dtsi

>
>