Re: [PATCH v7 3/3] thermal: tegra: add get_trend ops

Wei Ni
2019-02-19T02:15:13Z

On 18/2/2019 6:27 PM, Daniel Lezcano wrote:
> On 03/01/2019 11:12, 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 fd2703c0cfc5..864205af104b 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);
>
> No need to use the mutex here.
>
> Why not ?
>
> temp = READ_ONCE(tz->temperature);
> last_temp = READ_ONCE(tz->last_temperature);

Yes, you are right, will change it in next version.

Wei.

>
>> + 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;
>> +}
>> +
>> static const struct thermal_zone_of_device_ops tegra_of_thermal_ops = {
>> .get_temp = tegra_thermctl_get_temp,
>> .set_trip_temp = tegra_thermctl_set_trip_temp,
>> + .get_trend = tegra_thermctl_get_trend,
>> };
>>
>> static int get_hot_temp(struct thermal_zone_device *tz, int *trip, int *temp)
>>
>
>