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From:   Balsam CHIHI <bchihi@baylibre.com>
Date:   Fri, 2 Sep 2022 17:36:19 +0200
Message-ID: <CAGuA+oo5HvBo6aVvpXmk+ZEgvAM_zBHW2JZLD376+s7uHpdJuA@mail.gmail.com>
Subject: Thermal Framework, Thermal Driver, Thermal Aggregation
To:     rafael@kernel.org, rui.zhang@intel.com,
        Daniel Lezcano <daniel.lezcano@linaro.org>, amitk@kernel.org,
        Rob Herring <robh@kernel.org>,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@collabora.com>,
        Alexandre Bailon <abailon@baylibre.com>,
        Kevin Hilman <khilman@baylibre.com>
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Hello everybody,

I'm currently waiting for reviews of the LVTS Driver v9 series that I
recently submitted
"https://patchwork.kernel.org/project/linux-mediatek/cover/20220817080757.352021-1-bchihi@baylibre.com/",
then I will send the v10 with additional mt8195 specific code.
The upcoming v10 of the LVTS series will support Daniel's new Thermal
Framework implementation
"https://patchwork.kernel.org/project/linux-pm/cover/20220804224349.1926752-1-daniel.lezcano@linexp.org/",
plus new changes that may be requested from reviews of the v9.

After that, I will submit another series about Thermal Aggregation.
Basically, I need to create an additional thermal_zone with all
sensors registered to it, this will allow us to return MAX, AVG, or
MIN temperature based on all sensor values within this new
thermal_zone (could we call it Virtual?).
A series for the same purpose are sent by Alexandre Bailon
"https://patchwork.kernel.org/project/linux-pm/cover/20220218084604.1669091-1-abailon@baylibre.com/",
the implementation is done in "thermal_of.c" (I'm continuing on
Alexander's work). According to comments, other platforms not based on
Device Tree should benefit from this feature. So, according to Daniel
Lezcano, it should be implemented in "thermal_core.c" instead.

So, I would like to discuss it with you, and ask for recommendations
and help on how to implement this feature, because it is not easy for
me alone to figure out how to do it.
Should we update the thermal zone to support aggregation? or add a way
to register a thermal zone that aggregates other thermal zones?
what about applying some configuration to a multiple sensor thermal
zone? does it override the trip already defined in mono sensor thermal
zones?
And many other questions that should be asked to implement this new feature...
In my honest opinion, we should clarify together how it must be done.

Thank you in advance.

Best regards,
Balsam CHIHI