Re: [PATCH v7 4/4] thermal: mediatek: add another get_temp ops for thermal sensors - Amjad Ouled-Ameur

From: Amjad Ouled-Ameur <aouledameur@baylibre.com>
To: Daniel Lezcano <daniel.lezcano@linaro.org>,
	"Rafael J. Wysocki" <rafael@kernel.org>,
	Amit Kucheria <amitk@kernel.org>,
	Rob Herring <robh+dt@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Zhang Rui <rui.zhang@intel.com>
Cc: AngeloGioacchino Del Regno 
	<angelogioacchino.delregno@collabora.com>,
	Fabien Parent <fparent@baylibre.com>,
	Matthias Brugger <matthias.bgg@gmail.com>,
	Markus Schneider-Pargmann <msp@baylibre.com>,
	linux-pm@vger.kernel.org, Rob Herring <robh@kernel.org>,
	Michael Kao <michael.kao@mediatek.com>,
	linux-kernel@vger.kernel.org, Hsin-Yi Wang <hsinyi@chromium.org>,
	linux-arm-kernel@lists.infradead.org,
	linux-mediatek@lists.infradead.org, devicetree@vger.kernel.org
Subject: Re: [PATCH v7 4/4] thermal: mediatek: add another get_temp ops for thermal sensors
Date: Thu, 19 Jan 2023 18:03:07 +0100	[thread overview]
Message-ID: <187b0fe1-1f14-d8b8-c827-1e824da0b1d3@baylibre.com> (raw)
In-Reply-To: <0644aede-c281-3919-50e0-4466f6587d81@linaro.org>

Hi Daniel,

On 12/29/22 16:49, Daniel Lezcano wrote:
> On 06/12/2022 10:18, Amjad Ouled-Ameur wrote:
>> Hi Daniel,
>> On Mon Dec 5, 2022 at 8:39 PM CET, Daniel Lezcano wrote:
>>>
>>> Hi Amjad,
>>>
>>>
>>> On 05/12/2022 11:41, Amjad Ouled-Ameur wrote:
>>>
>>> [ ... ]
>>>
>>>>>> @@ -1161,11 +1197,24 @@ static int mtk_thermal_probe(struct platform_device *pdev)
>>>>>>             platform_set_drvdata(pdev, mt);
>>>>>>     -    tzdev = devm_thermal_of_zone_register(&pdev->dev, 0, mt,
>>>>>> -                          &mtk_thermal_ops);
>>>>>> -    if (IS_ERR(tzdev)) {
>>>>>> -        ret = PTR_ERR(tzdev);
>>>>>> -        goto err_disable_clk_peri_therm;
>>>>>> +    for (i = 0; i < mt->conf->num_sensors + 1; i++) {
>>>>>> +        tz = devm_kmalloc(&pdev->dev, sizeof(*tz), GFP_KERNEL);
>>>>>> +        if (!tz)
>>>>>> +            return -ENOMEM;
>>>>>> +
>>>>>> +        tz->mt = mt;
>>>>>> +        tz->id = i;
>>>>>> +
>>>>>> +        tzdev = devm_thermal_of_zone_register(&pdev->dev, i, tz, (i == 0) ?
>>>>>> +                                 &mtk_thermal_ops :
>>>>>> + &mtk_thermal_sensor_ops);
>>>>>
>>>>> Here you use again the aggregation
>>>> I addressed this concern in V6, could you please take a look and let me
>>>> know what you think [0].
>>>>
>>>> [0]: https://lore.kernel.org/all/5eb0cdc2-e9f9-dd42-bf80-b7dcd8bcc196@baylibre.com/
>>>
>>> May I misunderstanding but AFAICS, this patch is setting the
>>> mtk_thermal_ops if the sensor id is zero. The get_temp is computing the
>>> max temperature in this ops which is what we don't want to do.
>>
>> Correct, but I think that is out of scope of this patchset, as the current
>> driver already uses mtk_thermal_ops for sensor 0. The focus of this patchset
>> is to add support for the other sensors.
>>
>> Besides, what do you suggest as a clean implementation if the current one
>> no longer meets thermal core requirements ?
>
> 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.

Regards,

Amjad

>
> If it is the case, then a thermal zone per sensor with the trip points and a cooling device for each of them.
>
> The two thermal zones for the big will share the same cooling device. The little thermal zone will have its own cooling device.
>
> If there is the GPU, then its own cooling device also with devfreq.
>
>
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>