Hi Caesar,

On Wed, May 25, 2016 at 11:47:45AM +0800, Caesar Wang wrote:
> From: Sascha Hauer <s.ha...@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.perttu...@kapsi.fi>
> 
> Signed-off-by: Sascha Hauer <s.ha...@pengutronix.de>
> Signed-off-by: Caesar Wang <w...@rock-chips.com>
> Cc: Zhang Rui <rui.zh...@intel.com>
> Cc: Eduardo Valentin <edubez...@gmail.com>
> Cc: linux...@vger.kernel.org
> 
> ---
> 
> 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      | 52 
> +++++++++++++++++++++++++++++++++++++
>  include/linux/thermal.h             |  7 +++++
>  3 files changed, 66 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);

In the v2 review
(http://article.gmane.org/gmane.linux.documentation/38442) you agreed
to add locking but you haven't done it.  Maybe you sent the wrong
version?

Cheers,
Javi

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