On 四, 2012-07-26 at 22:11 +0200, Rafael J. Wysocki wrote:
> On Thursday, July 26, 2012, Zhang Rui wrote:
> > According to ACPI spec, tc1 and tc2 are used by OSPM
> > to anticipate the temperature trends.
> > We introduced the same concept to the generic thermal layer
> > for passive cooling, but now it seems that these values
> > are hard to be used on other platforms.
> >
> > So We introduce .get_trend() as a more general solution.
> >
> > For the platform thermal drivers that have their own way to
> > anticipate the temperature trends, they should provide
> > their own .get_trend() callback.
> > Or else, we will calculate the temperature trends by simply
> > comparing the current temperature and the cached previous
> > temperature reading.
>
> As far as the code is concerned:
>
> Reviewed-by: Rafael J. Wysocki <rjw@xxxxxxx>
>
> I wonder, though, if there are any users of the thermal core currently in the
> tree who should introduce their own .get_trend() callbacks?
>
No, for now.
But there will be soon. :)
thanks,
rui
> Rafael
>
>
> > Signed-off-by: Zhang Rui <rui.zhang@xxxxxxxxx>
> > ---
> > drivers/acpi/thermal.c | 33 +++++++++++++++++++++++++++++++++
> > drivers/thermal/thermal_sys.c | 19 +++++++++++++++++--
> > include/linux/thermal.h | 9 +++++++++
> > 3 files changed, 59 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/acpi/thermal.c b/drivers/acpi/thermal.c
> > index b48ec3e..0c49e42 100644
> > --- a/drivers/acpi/thermal.c
> > +++ b/drivers/acpi/thermal.c
> > @@ -704,6 +704,38 @@ static int thermal_get_crit_temp(struct thermal_zone_device *thermal,
> > return -EINVAL;
> > }
> >
> > +static int thermal_get_trend(struct thermal_zone_device *thermal,
> > + int trip, enum thermal_trend *trend)
> > +{
> > + struct acpi_thermal *tz = thermal->devdata;
> > + enum thermal_trip_type type;
> > + int i;
> > +
> > + if (thermal_get_trip_type(thermal, trip, &type))
> > + return -EINVAL;
> > +
> > + /* Only PASSIVE trip points need TREND */
> > + if (type != THERMAL_TRIP_PASSIVE)
> > + return -EINVAL;
> > +
> > + /*
> > + * tz->temperature has already been updated by generic thermal layer,
> > + * before this callback being invoked
> > + */
> > + i = (tz->trips.passive.tc1 * (tz->temperature - tz->last_temperature))
> > + + (tz->trips.passive.tc2
> > + * (tz->temperature - tz->trips.passive.temperature));
> > +
> > + if (i > 0)
> > + *trend = THERMAL_TREND_RAISING;
> > + else if (i < 0)
> > + *trend = THERMAL_TREND_DROPPING;
> > + else
> > + *trend = THERMAL_TREND_STABLE;
> > + return 0;
> > +}
> > +
> > +
> > static int thermal_notify(struct thermal_zone_device *thermal, int trip,
> > enum thermal_trip_type trip_type)
> > {
> > @@ -836,6 +868,7 @@ static const struct thermal_zone_device_ops acpi_thermal_zone_ops = {
> > .get_trip_type = thermal_get_trip_type,
> > .get_trip_temp = thermal_get_trip_temp,
> > .get_crit_temp = thermal_get_crit_temp,
> > + .get_trend = thermal_get_trend,
> > .notify = thermal_notify,
> > };
> >
> > diff --git a/drivers/thermal/thermal_sys.c b/drivers/thermal/thermal_sys.c
> > index 62b4279..68c93d4 100644
> > --- a/drivers/thermal/thermal_sys.c
> > +++ b/drivers/thermal/thermal_sys.c
> > @@ -723,6 +723,20 @@ static void thermal_zone_device_passive(struct thermal_zone_device *tz,
> > struct thermal_cooling_device *cdev;
> > long state, max_state;
> >
> > + if (!tz->ops->get_trend ||
> > + tz->ops->get_trend(tz, trip, (enum thermal_trend *)&trend)) {
> > + /*
> > + * compare the current temperature and previous temperature
> > + * to get the thermal trend, if no special requirement
> > + */
> > + if (tz->temperature > tz->last_temperature)
> > + trend = THERMAL_TREND_RAISING;
> > + else if (tz->temperature < tz->last_temperature)
> > + trend = THERMAL_TREND_DROPPING;
> > + else
> > + trend = THERMAL_TREND_STABLE;
> > + }
> > +
> > /*
> > * Above Trip?
> > * -----------
> > @@ -1091,6 +1105,9 @@ void thermal_zone_device_update(struct thermal_zone_device *tz)
> > goto leave;
> > }
> >
> > + tz->last_temperature = tz->temperature;
> > + tz->temperature = temp;
> > +
> > for (count = 0; count < tz->trips; count++) {
> > tz->ops->get_trip_type(tz, count, &trip_type);
> > tz->ops->get_trip_temp(tz, count, &trip_temp);
> > @@ -1150,8 +1167,6 @@ void thermal_zone_device_update(struct thermal_zone_device *tz)
> > thermal_zone_device_passive(tz, temp, tz->forced_passive,
> > THERMAL_TRIPS_NONE);
> >
> > - tz->last_temperature = temp;
> > -
> > leave:
> > if (tz->passive)
> > thermal_zone_device_set_polling(tz, tz->passive_delay);
> > diff --git a/include/linux/thermal.h b/include/linux/thermal.h
> > index a43b12c..a01e3e6 100644
> > --- a/include/linux/thermal.h
> > +++ b/include/linux/thermal.h
> > @@ -44,6 +44,12 @@ enum thermal_trip_type {
> > THERMAL_TRIP_CRITICAL,
> > };
> >
> > +enum thermal_trend {
> > + THERMAL_TREND_STABLE, /* temperature is stable */
> > + THERMAL_TREND_RAISING, /* temperature is raising */
> > + THERMAL_TREND_DROPPING, /* temperature is dropping */
> > +};
> > +
> > struct thermal_zone_device_ops {
> > int (*bind) (struct thermal_zone_device *,
> > struct thermal_cooling_device *);
> > @@ -65,6 +71,8 @@ struct thermal_zone_device_ops {
> > int (*set_trip_hyst) (struct thermal_zone_device *, int,
> > unsigned long);
> > int (*get_crit_temp) (struct thermal_zone_device *, unsigned long *);
> > + int (*get_trend) (struct thermal_zone_device *, int,
> > + enum thermal_trend *);
> > int (*notify) (struct thermal_zone_device *, int,
> > enum thermal_trip_type);
> > };
> > @@ -111,6 +119,7 @@ struct thermal_zone_device {
> > int tc2;
> > int passive_delay;
> > int polling_delay;
> > + int temperature;
> > int last_temperature;
> > bool passive;
> > unsigned int forced_passive;
> >
>
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