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

Zhang Rui
2016-06-22T03:15:19Z

On 一, 2016-06-06 at 19:44 +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 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.
>
>  Documentation/thermal/sysfs-api.txt |  7 +++++
>  drivers/thermal/thermal_core.c      | 54
> +++++++++++++++++++++++++++++++++++++
>  drivers/thermal/thermal_sysfs.c     |  3 +++
>  include/linux/thermal.h             | 10 +++++++
>  4 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.
>   .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 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)
>   monitor_thermal_zone(tz);
>  }
>
> +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);
> +
> + /*
> +  * 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);
> +
> +exit:
> + mutex_unlock(&tz->lock);
> +}
> +EXPORT_SYMBOL_GPL(thermal_zone_set_trips);
> +
>  static void update_temperature(struct thermal_zone_device *tz)
>  {
>   int temp, ret;
> @@ -417,6 +467,8 @@ 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);
>  }
> @@ -1175,6 +1227,8 @@ thermal_zone_device_register(const char *type,
> int trips, int mask,
>   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;
>
>   /* sys I/F */
>   /* 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,
>   ret = tz->ops->set_trip_hyst(tz, trip, temperature);
>   mutex_unlock(&tz->lock);
>
> + if (!ret)
> + thermal_zone_set_trips(tz);
> +
>   return ret ? ret : count;
>  }
>
> 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 {
>   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 *,
> @@ -169,6 +170,10 @@ struct thermal_attr {
>   * @last_temperature: previous temperature read
>   * @emul_temperature: emulated temperature when using
> CONFIG_THERMAL_EMULATION
>   * @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.
>   * @forced_passive: If > 0, temperature at which to switch on
> all ACPI
>   * processor cooling devices.  Currently only
> used by the
>   * step-wise governor.
> @@ -201,6 +206,8 @@ 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;
> @@ -428,6 +435,7 @@ int thermal_zone_bind_cooling_device(struct
> thermal_zone_device *, int,
>  int thermal_zone_unbind_cooling_device(struct thermal_zone_device *,
> int,
>          struct thermal_cooling_device
> *);
>  void thermal_zone_device_update(struct thermal_zone_device *);
> +void thermal_zone_set_trips(struct thermal_zone_device *);
>
>  struct thermal_cooling_device *thermal_cooling_device_register(char
> *, void *,
>   const struct thermal_cooling_device_ops *);
> @@ -477,6 +485,8 @@ static inline int
> thermal_zone_unbind_cooling_device(
>  { return -ENODEV; }
>  static inline void thermal_zone_device_update(struct
> thermal_zone_device *tz)
>  { }
> +static inline void thermal_zone_set_trips(struct thermal_zone_device
> *tz)
> +{ }
>  static inline struct thermal_cooling_device *
>  thermal_cooling_device_register(char *type, void *devdata,
>   const struct thermal_cooling_device_ops *ops)

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