linux-kernel - Re: [PATCH v2 01/14] thermal/core: Change thermal_zone_ops to thermal_sensor

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Message-ID: <CAJZ5v0ik_JQ4Awtw7iR68W4-9ZL8FRDsDd-kWmL-n09fgg3reg@mail.gmail.com>
Date:   Tue, 17 May 2022 17:42:28 +0200
From:   "Rafael J. Wysocki" <rafael@...nel.org>
To:     Daniel Lezcano <daniel.lezcano@...exp.org>
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Subject: Re: [PATCH v2 01/14] thermal/core: Change thermal_zone_ops to thermal_sensor_ops

On Sat, May 7, 2022 at 2:55 PM Daniel Lezcano <daniel.lezcano@...exp.org> wrote:
>
> A thermal zone is software abstraction of a sensor associated with
> properties and cooling devices if any.
>
> The fact that we have thermal_zone and thermal_zone_ops mixed is
> confusing and does not clearly identify the different components
> entering in the thermal management process. A thermal zone appears to
> be a sensor while it is not.

Well, the majority of the operations in thermal_zone_ops don't apply
to thermal sensors.  For example, ->set_trips(), ->get_trip_type(),
->get_trip_temp().

> In order to set the scene for multiple thermal sensors aggregated into
> a single thermal zone. Rename the thermal_zone_ops to
> thermal_sensor_ops, that will appear clearyl the thermal zone is not a
> sensor but an abstraction of one [or multiple] sensor(s).

So I'm not convinced that the renaming mentioned above is particularly
clean either.

IMV the way to go would be to split the thermal sensor operations,
like ->get_temp(), out of thermal_zone_ops.

But then it is not clear what a thermal zone with multiple sensors in
it really means.  I guess it would require an aggregation function to
combine the thermal sensors in it that would produce an effective
temperature to check against the trip points.

Honestly, I don't think that setting a separate set of trips for each
sensor in a thermal zone would make a lot of sense.