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SubjectRe: [PATCH] thermal: tegra: add get_trend ops
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Hi all,
Does there have any more comments for this patch?

Thanks.
Wei.

On 21/11/2018 2:36 PM, Wei Ni wrote:
>
>
> On 20/11/2018 11:38 PM, Thierry Reding wrote:
>> On Tue, Nov 20, 2018 at 05:11:17PM +0800, Wei Ni wrote:
>>> Add support for get_trend ops that allows soctherm
>>> sensors to be used with the step-wise governor.
>>>
>>> Signed-off-by: Wei Ni <wni@nvidia.com>
>>> ---
>>> drivers/thermal/tegra/soctherm.c | 34 ++++++++++++++++++++++++++++++++++
>>> 1 file changed, 34 insertions(+)
>>>
>>> diff --git a/drivers/thermal/tegra/soctherm.c b/drivers/thermal/tegra/soctherm.c
>>> index ed28110a3535..d2951fbe2b7c 100644
>>> --- a/drivers/thermal/tegra/soctherm.c
>>> +++ b/drivers/thermal/tegra/soctherm.c
>>> @@ -488,9 +488,43 @@ static int tegra_thermctl_set_trip_temp(void *data, int trip, int temp)
>>> return 0;
>>> }
>>>
>>> +static int tegra_thermctl_get_trend(void *data, int trip,
>>> + enum thermal_trend *trend)
>>> +{
>>> + struct tegra_thermctl_zone *zone = data;
>>> + struct thermal_zone_device *tz = zone->tz;
>>> + int trip_temp, temp, last_temp, ret;
>>> +
>>> + if (!tz)
>>> + return -EINVAL;
>>> +
>>> + ret = tz->ops->get_trip_temp(zone->tz, trip, &trip_temp);
>>> + if (ret)
>>> + return ret;
>>> +
>>> + mutex_lock(&tz->lock);
>>> + temp = tz->temperature;
>>> + last_temp = tz->last_temperature;
>>> + mutex_unlock(&tz->lock);
>>> +
>>> + if (temp > trip_temp) {
>>> + if (temp >= last_temp)
>>> + *trend = THERMAL_TREND_RAISING;
>>> + else
>>> + *trend = THERMAL_TREND_STABLE;
>>> + } else if (temp < trip_temp) {
>>> + *trend = THERMAL_TREND_DROPPING;
>>> + } else {
>>> + *trend = THERMAL_TREND_STABLE;
>>> + }
>>> +
>>> + return 0;
>>> +}
>>
>> This looks like a reimplementation of the get_tz_trend() helper. Is
>> seems like that helper already has everything we need. Perhaps this
>> isn't working because of-thermal installs of_thermal_get_trend(), a
>> function that returns -EINVAL if the driver doesn't implement the
>> ->get_trend() callback.
>
> 1. The get_tz_trend() helper can work, because it has:
> if (tz->emul_temperature || !tz->ops->get_trend ||
> tz->ops->get_trend(tz, trip, &trend)) {
> ...
> }
> the tz->ops->get_trend is of_thermal_get_trend(). If without special
> get_trend(), it will return -EINVAL, so it will implement the if block
> to get the "trend". If we have the special get_trend(), then the
> of_thermal_get_trend() will return 0, so this helper will not implement
> the if block, it will get the "trend" from the special get_trend().
>
> 2. There has a little difference between the helper and our special
> callback. The tegra_thermctl_get_trend() consider the trip_temp, but the
> get_tz_trend() helper didn't.
>
>>
>> Perhaps a better way would be to do something like this in
>> thermal_zone_of_add_sensor():
>>
>> if (ops->get_trend)
>> tzd->ops->get_trend = of_thermal_get_trend;
>>
>> That's similar to how ->set_trips() and ->set_emul_temp() are set up
>> and should make sure that get_tz_trend() will do the right thing for
>> all drivers that don't implement a special ->get_trend().
>
> As above description, I think the of_thermal_get_trend() already can
> handle this case, doesn't need to change.
>
> Wei.
>
>>
>> Thierry
>>

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