Re: [RFC PATCH 4/12] thermal: introduce .get_trend() callback

[Eduardo Valentin <eduardo.valentin@ti.com>]

Hello Rui,

On Mon, Jun 11, 2012 at 11:20:06AM +0800, Zhang Rui wrote:
> 
> tc1 and tc2 are ACPI platform specific concepts, introduce
> .get_trend() as a more general solution.
> 
> 
> Signed-off-by: Zhang Rui <rui.zhang@intel.com>
> ---
>  drivers/acpi/thermal.c        |   32 ++++++++++++++++++++++++++++++++
>  drivers/thermal/thermal_sys.c |   19 +++++++++++++++++--
>  include/linux/thermal.h       |    9 +++++++++
>  3 files changed, 58 insertions(+), 2 deletions(-)
> 
> Index: rtd3/drivers/acpi/thermal.c
> ===================================================================
> --- rtd3.orig/drivers/acpi/thermal.c
> +++ rtd3/drivers/acpi/thermal.c
> @@ -706,6 +706,37 @@ static int thermal_get_crit_temp(struct
>  		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;
> +	unsigned long trip_temp;
> +	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;
> +
> +	if (thermal_get_trip_temp(thermal, trip, &trip_temp))
> +		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 - trip_temp));
> +
> +	*trend = i > 0 ? THERMAL_TREND_RAISING :
> +		(i < 0 ? THERMAL_TREND_DROPPING : THERMAL_TREND_NONE);
> +	return 0;
> +}
> +
> +
>  static int thermal_notify(struct thermal_zone_device *thermal, int trip,
>  			   enum thermal_trip_type trip_type)
>  {
> @@ -835,6 +866,7 @@ static const struct thermal_zone_device_
>  	.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,
>  };
>  
> Index: rtd3/drivers/thermal/thermal_sys.c
> ===================================================================
> --- rtd3.orig/drivers/thermal/thermal_sys.c
> +++ rtd3/drivers/thermal/thermal_sys.c
> @@ -657,6 +657,18 @@ thermal_remove_hwmon_sysfs(struct therma
>  }
>  #endif
>  
> +static void thermal_get_trend (struct thermal_zone_device *tz,
> +		int trip, enum thermal_trend *trend)
> +{
> +	if (tz->ops->get_trend)
> +		if (!tz->ops->get_trend(tz, trip, trend))
> +			return;
> +
> +	*trend = tz->temperature >= tz->last_temperature ?
> +		 THERMAL_TREND_RAISING : THERMAL_TREND_DROPPING;
> +	return;
> +}
> +
>  static void thermal_zone_device_set_polling(struct thermal_zone_device *tz,
>  					    int delay)
>  {
> @@ -691,6 +703,8 @@ static void thermal_zone_device_passive(
>  	if (temp >= trip_temp) {
>  		tz->passive = true;
>  
> +		thermal_get_trend(tz, trip, (enum thermal_trend *)&trend);
> +
>  		trend = (tz->tc1 * (temp - tz->last_temperature)) +
>  			(tz->tc2 * (temp - trip_temp));
>  
> @@ -1049,6 +1063,9 @@ void thermal_zone_device_update(struct t
>  		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);
> @@ -1108,8 +1125,6 @@ void thermal_zone_device_update(struct t
>  		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);
> Index: rtd3/include/linux/thermal.h
> ===================================================================
> --- rtd3.orig/include/linux/thermal.h
> +++ rtd3/include/linux/thermal.h
> @@ -44,6 +44,12 @@ enum thermal_trip_type {
>  	THERMAL_TRIP_CRITICAL,
>  };
>  
> +enum thermal_trend {
> +	THERMAL_TREND_NONE,
> +	THERMAL_TREND_RAISING,
> +	THERMAL_TREND_DROPPING,
> +};
> +

Nip: Can you please add some doc for the expected definition for all enum entries above?
Is TREND_NONE supposed to mean "Stable", for instance?

>  struct thermal_zone_device_ops {
>  	int (*bind) (struct thermal_zone_device *,
>  		     struct thermal_cooling_device *);
> @@ -59,6 +65,8 @@ struct thermal_zone_device_ops {
>  	int (*get_trip_temp) (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);
>  };
> @@ -95,6 +103,7 @@ struct thermal_zone_device {
>  	int tc2;
>  	int passive_delay;
>  	int polling_delay;
> +	int temperature;
>  	int last_temperature;
>  	bool passive;
>  	unsigned int forced_passive;
> 
>