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

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Message-ID: <584a1927-0713-4a6d-a7a6-94bdda30dc0d@linaro.org>
Date:   Tue, 27 Sep 2022 14:20:39 +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 27/09/2022 12:38, Rafael J. Wysocki wrote:
> On Tue, Sep 27, 2022 at 12:11 AM Daniel Lezcano
> <daniel.lezcano@...aro.org> wrote:
>>
>> 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)
>>         |                 ^~
> 
> This is about indentation, though, so it looks like white space is
> mangled somehow.
> 
> As a matter of correctness, the inner parens are not needed.

Oh, actually I did a confusion with the 'brackets', you meant:

(t.temperature != trip->temperature && tz->ops->set_trip_temp)

right ?

>>>> +       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.
> 
> Do those drivers set tz->trips?  If not, the tz->trips check can go
> before the ops ones.

Unfortunately some are doing that, like the tegra's soctherm driver


>> [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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