Re: [PATCH v5 1/5] thermal: Add support for hardware-tracked trip points

[Zhang Rui]

On ä, 2016-06-06 at 19:44 +0800, Caesar Wang wrote:
> From: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
> 
> This adds support for hardware-tracked trip points to the device tree
> thermal sensor framework.
> 
> The framework supports an arbitrary number of trip points. Whenever
> the current temperature is updated, the trip points immediately
> below and above the current temperature are found. A .set_trips
> callback is then called with the temperatures. If there is no trip
> point above or below the current temperature, the passed trip
> temperature will be -INT_MAX or INT_MAX respectively. In this
> callback,
> the driver should program the hardware such that it is notified
> when either of these trip points are triggered. When a trip point
> is triggered, the driver should call `thermal_zone_device_update'
> for the respective thermal zone. This will cause the trip points
> to be updated again.
> 
> If .set_trips is not implemented, the framework behaves as before.
> 
> This patch is based on an earlier version from Mikko Perttunen
> <mikko.perttunen@xxxxxxxx>
> 
> Signed-off-by: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
> Signed-off-by: Caesar Wang <wxt@xxxxxxxxxxxxxx>
> Cc: Zhang Rui <rui.zhang@xxxxxxxxx>
> Cc: Eduardo Valentin <edubezval@xxxxxxxxx>
> Cc: linux-pm@xxxxxxxxxxxxxxx
> 
> ---
> 
> Changes in v5:
> - add the lock for thermal_zone_set_trips function.
> - change based on next kernel.
> 
> Changes in v4:
> - Missing the lock added in v3.
> 
> Changes in v3:
> - as Javi comments on https://patchwork.kernel.org/patch/9001281/.
> - add the lock for preventing the called from multi placce
> - add the note for pre_low/high_trip.
> 
> Changes in v2:
> - update the sysfs-api.txt for set_trips.
> 
> ÂDocumentation/thermal/sysfs-api.txt |ÂÂ7 +++++
> Âdrivers/thermal/thermal_core.cÂÂÂÂÂÂ| 54
> +++++++++++++++++++++++++++++++++++++
> Âdrivers/thermal/thermal_sysfs.cÂÂÂÂÂ|ÂÂ3 +++
> Âinclude/linux/thermal.hÂÂÂÂÂÂÂÂÂÂÂÂÂ| 10 +++++++
> Â4 files changed, 74 insertions(+)
> 
> diff --git a/Documentation/thermal/sysfs-api.txt
> b/Documentation/thermal/sysfs-api.txt
> index efc3f3d..75d8838 100644
> --- a/Documentation/thermal/sysfs-api.txt
> +++ b/Documentation/thermal/sysfs-api.txt
> @@ -49,6 +49,9 @@ temperature) and throttle appropriate devices.
> Â	.bind: bind the thermal zone device with a thermal cooling
> device.
> Â	.unbind: unbind the thermal zone device with a thermal
> cooling device.
> Â	.get_temp: get the current temperature of the thermal zone.
> +	.set_trips: set the trip points window. Whenever the current
> temperature
> +		ÂÂÂÂis updated, the trip points immediately below
> and above the
> +		ÂÂÂÂcurrent temperature are found.
> Â	.get_mode: get the current mode (enabled/disabled) of the
> thermal zone.
> Â	ÂÂÂÂ- "enabled" means the kernel thermal management is
> enabled.
> Â	ÂÂÂÂ- "disabled" will prevent kernel thermal driver action
> upon trip points
> @@ -95,6 +98,10 @@ temperature) and throttle appropriate devices.
> Â			get_temp:	a pointer to a function
> that reads the
> Â					sensor temperature. This is
> mandatory
> Â					callback provided by sensor
> driver.
> +			set_trips:ÂÂÂÂÂÂa pointer to a function that
> sets a
> +					temperature window. When
> this window is
> +					left the driver must inform
> the thermal
> +					core via
> thermal_zone_device_update.
> Â			get_trend:Â	a pointer to a function
> that reads the
> Â					sensor temperature trend.
> Â			set_emul_temp:	a pointer to a
> function that sets
> diff --git a/drivers/thermal/thermal_core.c
> b/drivers/thermal/thermal_core.c
> index 792aab7..e69aee2 100644
> --- a/drivers/thermal/thermal_core.c
> +++ b/drivers/thermal/thermal_core.c
> @@ -368,6 +368,56 @@ static void handle_thermal_trip(struct
> thermal_zone_device *tz, int trip)
> Â	monitor_thermal_zone(tz);
> Â}
> Â
> +void thermal_zone_set_trips(struct thermal_zone_device *tz)
> +{
> +	int low = -INT_MAX;
> +	int high = INT_MAX;
> +	int trip_temp, hysteresis;
> +	int i, ret;
> +
> +	mutex_lock(&tz->lock);
> +
> +	if (!tz->ops->set_trips)
> +		goto exit;
> +
	if (!tz->ops->get_trip_hyst)
		goto exit;

otherwise, the patch looks good to me.

thanks,
rui
> +	for (i = 0; i < tz->trips; i++) {
> +		int trip_low;
> +
> +		tz->ops->get_trip_temp(tz, i, &trip_temp);
> +		tz->ops->get_trip_hyst(tz, i, &hysteresis);
> +
> +		trip_low = trip_temp - hysteresis;
> +
> +		if (trip_low < tz->temperature && trip_low > low)
> +			low = trip_low;
> +
> +		if (trip_temp > tz->temperature && trip_temp < high)
> +			high = trip_temp;
> +	}
> +
> +	/* No need to change trip points */
> +	if (tz->prev_low_trip == low && tz->prev_high_trip == high)
> +		goto exit;
> +
> +	tz->prev_low_trip = low;
> +	tz->prev_high_trip = high;
> +
> +	dev_dbg(&tz->device, "new temperature boundaries: %d < x <
> %d\n",
> +			low, high);
> +
> +	/*
> +	Â* Set a temperature window. When this window is left the
> driver
> +	Â* must inform the thermal core via
> thermal_zone_device_update.
> +	Â*/
> +	ret = tz->ops->set_trips(tz, low, high);
> +	if (ret)
> +		dev_err(&tz->device, "Failed to set trips: %d\n",
> ret);
> +
> +exit:
> +	mutex_unlock(&tz->lock);
> +}
> +EXPORT_SYMBOL_GPL(thermal_zone_set_trips);
> +
> Âstatic void update_temperature(struct thermal_zone_device *tz)
> Â{
> Â	int temp, ret;
> @@ -417,6 +467,8 @@ void thermal_zone_device_update(struct
> thermal_zone_device *tz)
> Â
> Â	update_temperature(tz);
> Â
> +	thermal_zone_set_trips(tz);
> +
> Â	for (count = 0; count < tz->trips; count++)
> Â		handle_thermal_trip(tz, count);
> Â}
> @@ -1175,6 +1227,8 @@ thermal_zone_device_register(const char *type,
> int trips, int mask,
> Â	tz->trips = trips;
> Â	tz->passive_delay = passive_delay;
> Â	tz->polling_delay = polling_delay;
> +	tz->prev_low_trip = INT_MAX;
> +	tz->prev_high_trip = -INT_MAX;
> Â
> Â	/* sys I/F */
> Â	/* Add nodes that are always present via .groups */
> diff --git a/drivers/thermal/thermal_sysfs.c
> b/drivers/thermal/thermal_sysfs.c
> index 743df50..33bbe30 100644
> --- a/drivers/thermal/thermal_sysfs.c
> +++ b/drivers/thermal/thermal_sysfs.c
> @@ -219,6 +219,9 @@ trip_point_hyst_store(struct device *dev, struct
> device_attribute *attr,
> Â	ret = tz->ops->set_trip_hyst(tz, trip, temperature);
> Â	mutex_unlock(&tz->lock);
> Â
> +	if (!ret)
> +		thermal_zone_set_trips(tz);
> +
> Â	return ret ? ret : count;
> Â}
> Â
> diff --git a/include/linux/thermal.h b/include/linux/thermal.h
> index ea667b6..780e69d 100644
> --- a/include/linux/thermal.h
> +++ b/include/linux/thermal.h
> @@ -99,6 +99,7 @@ struct thermal_zone_device_ops {
> Â	int (*unbind) (struct thermal_zone_device *,
> Â		ÂÂÂÂÂÂÂstruct thermal_cooling_device *);
> Â	int (*get_temp) (struct thermal_zone_device *, int *);
> +	int (*set_trips) (struct thermal_zone_device *, int, int);
> Â	int (*get_mode) (struct thermal_zone_device *,
> Â			Âenum thermal_device_mode *);
> Â	int (*set_mode) (struct thermal_zone_device *,
> @@ -169,6 +170,10 @@ struct thermal_attr {
> Â * @last_temperature:	previous temperature read
> Â * @emul_temperature:	emulated temperature when using
> CONFIG_THERMAL_EMULATION
> Â * @passive:		1 if you've crossed a passive trip
> point, 0 otherwise.
> + * @prev_low_trip:	the low current temperature if you've
> crossed a passive
> +			trip point.
> + * @prev_high_trip:	the above current temperature if you've
> crossed a
> +			passive trip point.
> Â * @forced_passive:	If > 0, temperature at which to switch on
> all ACPI
> Â *			processor cooling devices.ÂÂCurrently only
> used by the
> Â *			step-wise governor.
> @@ -201,6 +206,8 @@ struct thermal_zone_device {
> Â	int last_temperature;
> Â	int emul_temperature;
> Â	int passive;
> +	int prev_low_trip;
> +	int prev_high_trip;
> Â	unsigned int forced_passive;
> Â	atomic_t need_update;
> Â	struct thermal_zone_device_ops *ops;
> @@ -428,6 +435,7 @@ int thermal_zone_bind_cooling_device(struct
> thermal_zone_device *, int,
> Âint thermal_zone_unbind_cooling_device(struct thermal_zone_device *,
> int,
> Â				ÂÂÂÂÂÂÂstruct thermal_cooling_device
> *);
> Âvoid thermal_zone_device_update(struct thermal_zone_device *);
> +void thermal_zone_set_trips(struct thermal_zone_device *);
> Â
> Âstruct thermal_cooling_device *thermal_cooling_device_register(char
> *, void *,
> Â		const struct thermal_cooling_device_ops *);
> @@ -477,6 +485,8 @@ static inline int
> thermal_zone_unbind_cooling_device(
> Â{ return -ENODEV; }
> Âstatic inline void thermal_zone_device_update(struct
> thermal_zone_device *tz)
> Â{ }
> +static inline void thermal_zone_set_trips(struct thermal_zone_device
> *tz)
> +{ }
> Âstatic inline struct thermal_cooling_device *
> Âthermal_cooling_device_register(char *type, void *devdata,
> Â	const struct thermal_cooling_device_ops *ops)