[v2,1/5] thermal: Add support for hardware-tracked trip points
diff mbox

Message ID 1462268013-14992-2-git-send-email-wxt@rock-chips.com
State New
Headers show

Commit Message

Caesar Wang May 3, 2016, 9:33 a.m. UTC
From: Sascha Hauer <s.hauer@pengutronix.de>

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@kapsi.fi>

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Caesar Wang <wxt@rock-chips.com>
Cc: Zhang Rui <rui.zhang@intel.com>
Cc: Eduardo Valentin <edubezval@gmail.com>
Cc: linux-pm@vger.kernel.org

---

Changes in v2:
- update the sysfs-api.txt for set_trips

 Documentation/thermal/sysfs-api.txt |  7 +++++
 drivers/thermal/thermal_core.c      | 52 +++++++++++++++++++++++++++++++++++++
 include/linux/thermal.h             |  3 +++
 3 files changed, 62 insertions(+)

Comments

Javi Merino May 24, 2016, 12:57 p.m. UTC | #1
On Tue, May 03, 2016 at 05:33:29PM +0800, Caesar Wang wrote:
> From: Sascha Hauer <s.hauer@pengutronix.de>
> 
> 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@kapsi.fi>
> 
> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
> Signed-off-by: Caesar Wang <wxt@rock-chips.com>
> Cc: Zhang Rui <rui.zhang@intel.com>
> Cc: Eduardo Valentin <edubezval@gmail.com>
> Cc: linux-pm@vger.kernel.org
> 
> ---
> 
> Changes in v2:
> - update the sysfs-api.txt for set_trips
> 
>  Documentation/thermal/sysfs-api.txt |  7 +++++
>  drivers/thermal/thermal_core.c      | 52 +++++++++++++++++++++++++++++++++++++
>  include/linux/thermal.h             |  3 +++
>  3 files changed, 62 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.
>  	.bind: bind the thermal zone device with a thermal cooling device.
>  	.unbind: unbind the thermal zone device with a thermal cooling device.
>  	.get_temp: get the current temperature of the thermal zone.
> +	.set_trips: set the trip points window. Whenever the current temperature
> +		    is updated, the trip points immediately below and above the
> +		    current temperature are found.
>  	.get_mode: get the current mode (enabled/disabled) of the thermal zone.
>  	    - "enabled" means the kernel thermal management is enabled.
>  	    - "disabled" will prevent kernel thermal driver action upon trip points
> @@ -95,6 +98,10 @@ temperature) and throttle appropriate devices.
>  			get_temp:	a pointer to a function that reads the
>  					sensor temperature. This is mandatory
>  					callback provided by sensor driver.
> +			set_trips:      a 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.
>  			get_trend: 	a pointer to a function that reads the
>  					sensor temperature trend.
>  			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 5133cd1..e5bfbd3 100644
> --- a/drivers/thermal/thermal_core.c
> +++ b/drivers/thermal/thermal_core.c
> @@ -520,6 +520,51 @@ exit:
>  }
>  EXPORT_SYMBOL_GPL(thermal_zone_get_temp);
>  
> +static void thermal_zone_set_trips(struct thermal_zone_device *tz)
> +{
> +	int low = -INT_MAX;
> +	int high = INT_MAX;
> +	int trip_temp, hysteresis;
> +	int temp = tz->temperature;
> +	int i, ret;
> +
> +	if (!tz->ops->set_trips)
> +		return;
> +
> +	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 < temp && trip_low > low)
> +			low = trip_low;
> +
> +		if (trip_temp > temp && trip_temp < high)
> +			high = trip_temp;
> +	}
> +
> +	/* No need to change trip points */
> +	if (tz->prev_low_trip == low && tz->prev_high_trip == high)
> +		return;
> +
> +	tz->prev_low_trip = low;
> +	tz->prev_high_trip = high;
> +
> +	dev_dbg(&tz->device, "new temperature boundaries: %d < x < %d\n",
> +			low, high);
> +
> +	/*
> +	 * Set a temperature window. When this window is left the driver
> +	 * must inform the thermal core via thermal_zone_device_update.
> +	 */
> +	ret = tz->ops->set_trips(tz, low, high);
> +	if (ret)
> +		dev_err(&tz->device, "Failed to set trips: %d\n", ret);

This function can be called at the same time from multiple places so
it should be reentrant.  I think you should call mutex_lock(tz->lock)
before "if (tz->prev_low_trip == low && ..." and unlock it here.

> +}
> +
>  static void update_temperature(struct thermal_zone_device *tz)
>  {
>  	int temp, ret;
> @@ -569,6 +614,8 @@ void thermal_zone_device_update(struct thermal_zone_device *tz)
>  
>  	update_temperature(tz);
>  
> +	thermal_zone_set_trips(tz);
> +
>  	for (count = 0; count < tz->trips; count++)
>  		handle_thermal_trip(tz, count);
>  }
> @@ -754,6 +801,9 @@ trip_point_hyst_store(struct device *dev, struct device_attribute *attr,
>  	 */
>  	ret = tz->ops->set_trip_hyst(tz, trip, temperature);
>  
> +	if (!ret)
> +		thermal_zone_set_trips(tz);
> +

You should add a similar call to thermal_zone_set_trips() in trip_point_temp_store()

>  	return ret ? ret : count;
>  }
>  
> @@ -1843,6 +1893,8 @@ struct thermal_zone_device *thermal_zone_device_register(const char *type,
>  	tz->trips = trips;
>  	tz->passive_delay = passive_delay;
>  	tz->polling_delay = polling_delay;
> +	tz->prev_low_trip = INT_MAX;
> +	tz->prev_high_trip = -INT_MAX;
>  	/* A new thermal zone needs to be updated anyway. */
>  	atomic_set(&tz->need_update, 1);
>  
> diff --git a/include/linux/thermal.h b/include/linux/thermal.h
> index e45abe7..e258359 100644
> --- a/include/linux/thermal.h
> +++ b/include/linux/thermal.h
> @@ -98,6 +98,7 @@ struct thermal_zone_device_ops {
>  	int (*unbind) (struct thermal_zone_device *,
>  		       struct thermal_cooling_device *);
>  	int (*get_temp) (struct thermal_zone_device *, int *);
> +	int (*set_trips) (struct thermal_zone_device *, int, int);
>  	int (*get_mode) (struct thermal_zone_device *,
>  			 enum thermal_device_mode *);
>  	int (*set_mode) (struct thermal_zone_device *,
> @@ -199,6 +200,8 @@ struct thermal_zone_device {
>  	int last_temperature;
>  	int emul_temperature;
>  	int passive;
> +	int prev_low_trip;
> +	int prev_high_trip;

Please document these fields in the kerneldoc comment before struct
thermal_zone_device.

>  	unsigned int forced_passive;
>  	atomic_t need_update;
>  	struct thermal_zone_device_ops *ops;

Cheers,
Javi

Patch
diff mbox

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.
 	.bind: bind the thermal zone device with a thermal cooling device.
 	.unbind: unbind the thermal zone device with a thermal cooling device.
 	.get_temp: get the current temperature of the thermal zone.
+	.set_trips: set the trip points window. Whenever the current temperature
+		    is updated, the trip points immediately below and above the
+		    current temperature are found.
 	.get_mode: get the current mode (enabled/disabled) of the thermal zone.
 	    - "enabled" means the kernel thermal management is enabled.
 	    - "disabled" will prevent kernel thermal driver action upon trip points
@@ -95,6 +98,10 @@  temperature) and throttle appropriate devices.
 			get_temp:	a pointer to a function that reads the
 					sensor temperature. This is mandatory
 					callback provided by sensor driver.
+			set_trips:      a 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.
 			get_trend: 	a pointer to a function that reads the
 					sensor temperature trend.
 			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 5133cd1..e5bfbd3 100644
--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c
@@ -520,6 +520,51 @@  exit:
 }
 EXPORT_SYMBOL_GPL(thermal_zone_get_temp);
 
+static void thermal_zone_set_trips(struct thermal_zone_device *tz)
+{
+	int low = -INT_MAX;
+	int high = INT_MAX;
+	int trip_temp, hysteresis;
+	int temp = tz->temperature;
+	int i, ret;
+
+	if (!tz->ops->set_trips)
+		return;
+
+	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 < temp && trip_low > low)
+			low = trip_low;
+
+		if (trip_temp > temp && trip_temp < high)
+			high = trip_temp;
+	}
+
+	/* No need to change trip points */
+	if (tz->prev_low_trip == low && tz->prev_high_trip == high)
+		return;
+
+	tz->prev_low_trip = low;
+	tz->prev_high_trip = high;
+
+	dev_dbg(&tz->device, "new temperature boundaries: %d < x < %d\n",
+			low, high);
+
+	/*
+	 * Set a temperature window. When this window is left the driver
+	 * must inform the thermal core via thermal_zone_device_update.
+	 */
+	ret = tz->ops->set_trips(tz, low, high);
+	if (ret)
+		dev_err(&tz->device, "Failed to set trips: %d\n", ret);
+}
+
 static void update_temperature(struct thermal_zone_device *tz)
 {
 	int temp, ret;
@@ -569,6 +614,8 @@  void thermal_zone_device_update(struct thermal_zone_device *tz)
 
 	update_temperature(tz);
 
+	thermal_zone_set_trips(tz);
+
 	for (count = 0; count < tz->trips; count++)
 		handle_thermal_trip(tz, count);
 }
@@ -754,6 +801,9 @@  trip_point_hyst_store(struct device *dev, struct device_attribute *attr,
 	 */
 	ret = tz->ops->set_trip_hyst(tz, trip, temperature);
 
+	if (!ret)
+		thermal_zone_set_trips(tz);
+
 	return ret ? ret : count;
 }
 
@@ -1843,6 +1893,8 @@  struct thermal_zone_device *thermal_zone_device_register(const char *type,
 	tz->trips = trips;
 	tz->passive_delay = passive_delay;
 	tz->polling_delay = polling_delay;
+	tz->prev_low_trip = INT_MAX;
+	tz->prev_high_trip = -INT_MAX;
 	/* A new thermal zone needs to be updated anyway. */
 	atomic_set(&tz->need_update, 1);
 
diff --git a/include/linux/thermal.h b/include/linux/thermal.h
index e45abe7..e258359 100644
--- a/include/linux/thermal.h
+++ b/include/linux/thermal.h
@@ -98,6 +98,7 @@  struct thermal_zone_device_ops {
 	int (*unbind) (struct thermal_zone_device *,
 		       struct thermal_cooling_device *);
 	int (*get_temp) (struct thermal_zone_device *, int *);
+	int (*set_trips) (struct thermal_zone_device *, int, int);
 	int (*get_mode) (struct thermal_zone_device *,
 			 enum thermal_device_mode *);
 	int (*set_mode) (struct thermal_zone_device *,
@@ -199,6 +200,8 @@  struct thermal_zone_device {
 	int last_temperature;
 	int emul_temperature;
 	int passive;
+	int prev_low_trip;
+	int prev_high_trip;
 	unsigned int forced_passive;
 	atomic_t need_update;
 	struct thermal_zone_device_ops *ops;