On Wed, Nov 21, 2018 at 02:36:10PM +0800, 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@xxxxxxxxxx>
> >> ---
> >> 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().
The idea of the helper is to provide a trend in case drivers dont have
a specific way of doing so.
>
> 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.
>
Yeah, if you are computing trend towards a trip, then yes, that is
different and this patch is needed.
> >
> > 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
> >
