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

Daniel Lezcano
2019-02-18T10:27:40Z

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);

> + 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)
>

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