Hello Rui and Rafael,
On Wed, Aug 1, 2012 at 5:42 AM, Zhang Rui <rui.zhang@xxxxxxxxx> wrote:
> 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. :)
Yeah, one of them would be the OMAP5 thermal driver. But the code is
not implemented yet. Currently driver under staging area already
though: drivers/staging/omap-thermal/
>
> 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;
>> >
>>
>
>
--
Eduardo Valentin
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