linux-kernel - Re: [PATCH v5 03/30] thermal/core: Add a generic thermal_zone_set

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Date:   Tue, 27 Sep 2022 00:11:49 +0200
From:   Daniel Lezcano <daniel.lezcano@...aro.org>
To:     "Rafael J. Wysocki" <rafael@...nel.org>
Cc:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Linux PM <linux-pm@...r.kernel.org>,
        "Zhang, Rui" <rui.zhang@...el.com>,
        Amit Kucheria <amitk@...nel.org>
Subject: Re: [PATCH v5 03/30] thermal/core: Add a generic
 thermal_zone_set_trip() function

On 26/09/2022 21:25, Rafael J. Wysocki wrote:

[ ... ]

>> +       if ((t.temperature != trip->temperature) && tz->ops->set_trip_temp) {
> 
> The inner parens are not needed here and below.
> 
>> +
> 
> And the extra empty line is not needed here (and below) too IMO.
> 
>> +               ret = tz->ops->set_trip_temp(tz, trip_id, trip->temperature);
>> +               if (ret)
>> +                       goto out;
>> +       }
>

Without the parens, the following happens:


warning: this ‘if’ clause does not guard... [-Wmisleading-indentation]
  1229 |         if ((t.temperature != trip->temperature) && 
tz->ops->set_trip_temp)
       |         ^~
note: ...this statement, but the latter is misleadingly indented as if 
it were guarded by the ‘if’
  1231 |                 if (ret)
       |                 ^~


>> +       if ((t.hysteresis != trip->hysteresis) && tz->ops->set_trip_hyst) {
>> +
>> +               ret = tz->ops->set_trip_hyst(tz, trip_id, trip->hysteresis);
>> +               if (ret)
>> +                       goto out;
>> +       }
>> +
>> +       if (((t.temperature != trip->temperature) ||
>> +            (t.hysteresis != trip->hysteresis)) && tz->trips)
>> +               tz->trips[trip_id] = *trip;
> 
> I would write this as
> 
> if (tz->trips && (t.temperature != trip->temperature || t.hysteresis
> != trip->hysteresis))
>          tz->trips[trip_id] = *trip;

Ok, sure

> But
> 
> 1. Do we want to copy the trip type here too?

The function thermal_zone_set_trip() is called from thermal_sysfs.c, it 
is the unique call site. However, I think it is a good idea to check the 
type of the trip point is not changed, even if it is not possible with 
the actual code.

> 2. If tz->trips is set, do we still want to invoke ->set_trip_temp()
> or ->set_trip_hyst() if they are present?

No but there are bogus drivers setting the interrupt with these ops 
instead of using the set_trips ops (eg. [1][2][3]). So in order to keep 
those working ATM, I'm keeping them and when all the drivers will be 
changed, I'll wipe out the set_trip_* ops from everywhere.

[1] drivers/thermal/samsung/exynos_tmu.c
[2] drivers/thermal/qcom/qcom-spmi-temp-alarm.c
[3] drivers/thermal/imx_thermal.c


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