linux-kernel - Re: [PATCH] thermal: add sysfs

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Date:	Thu, 25 Feb 2016 18:16:19 -0800
From:	Srikar Srimath Tirumala <srikars@...dia.com>
To:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] thermal: add sysfs_notify on some attributes

On 02/25/2016 04:12 PM, Srikar Srimath Tirumala wrote:
> Add a sysfs_notify on thermal_zone*/temp and cooling_device*/
> cur_state whenever any trip is triggered or cur state is changed.
>
> This change allows usermode apps to register themselves to get
> notified, when certain thermal conditions occur and reduce their
> workload. This workload throttling allows usermode to react before
> hardware clocks are throttled and keep some critical apps running
> reliably longer.
>
> Signed-off-by: Srikar Srimath Tirumala <srikars@...dia.com>
> ---
>   drivers/thermal/thermal_core.c | 34 ++++++++++++++++++++++++++--------
>   1 file changed, 26 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
> index a0a8fd1..f54519e 100644
> --- a/drivers/thermal/thermal_core.c
> +++ b/drivers/thermal/thermal_core.c
> @@ -419,14 +419,23 @@ static void monitor_thermal_zone(struct thermal_zone_device *tz)
>   	mutex_unlock(&tz->lock);
>   }
>
> -static void handle_non_critical_trips(struct thermal_zone_device *tz,
> +static int handle_non_critical_trips(struct thermal_zone_device *tz,
>   			int trip, enum thermal_trip_type trip_type)
>   {
> +	int trip_temp;
> +	int ret = 0;
> +
>   	tz->governor ? tz->governor->throttle(tz, trip) :
>   		       def_governor->throttle(tz, trip);
> +
> +	tz->ops->get_trip_temp(tz, trip, &trip_temp);
> +	if (tz->temperature >= trip_temp)
> +		ret = 1;
> +
> +	return ret;
>   }
>
> -static void handle_critical_trips(struct thermal_zone_device *tz,
> +static int handle_critical_trips(struct thermal_zone_device *tz,
>   				int trip, enum thermal_trip_type trip_type)
>   {
>   	int trip_temp;
> @@ -435,7 +444,7 @@ static void handle_critical_trips(struct thermal_zone_device *tz,
>
>   	/* If we have not crossed the trip_temp, we do not care. */
>   	if (trip_temp <= 0 || tz->temperature < trip_temp)
> -		return;
> +		return 0;
>
>   	trace_thermal_zone_trip(tz, trip, trip_type);
>
> @@ -448,23 +457,28 @@ static void handle_critical_trips(struct thermal_zone_device *tz,
>   			  tz->temperature / 1000);
>   		orderly_poweroff(true);
>   	}
> +
> +	return 1;
>   }
>
> -static void handle_thermal_trip(struct thermal_zone_device *tz, int trip)
> +static int handle_thermal_trip(struct thermal_zone_device *tz, int trip)
>   {
> +	int ret = 0;
>   	enum thermal_trip_type type;
>
>   	tz->ops->get_trip_type(tz, trip, &type);
>
>   	if (type == THERMAL_TRIP_CRITICAL || type == THERMAL_TRIP_HOT)
> -		handle_critical_trips(tz, trip, type);
> +		ret = handle_critical_trips(tz, trip, type);
>   	else
> -		handle_non_critical_trips(tz, trip, type);
> +		ret = handle_non_critical_trips(tz, trip, type);
>   	/*
>   	 * Alright, we handled this trip successfully.
>   	 * So, start monitoring again.
>   	 */
>   	monitor_thermal_zone(tz);
> +
> +	return ret;
>   }
>
>   /**
> @@ -556,7 +570,7 @@ static void thermal_zone_device_reset(struct thermal_zone_device *tz)
>   void thermal_zone_device_update(struct thermal_zone_device *tz)
>   {
>   	int count;
> -
> +	int trips = 0;
>   	if (atomic_read(&in_suspend))
>   		return;
>
> @@ -566,7 +580,10 @@ void thermal_zone_device_update(struct thermal_zone_device *tz)
>   	update_temperature(tz);
>
>   	for (count = 0; count < tz->trips; count++)
> -		handle_thermal_trip(tz, count);
> +		trips += handle_thermal_trip(tz, count);
> +
> +	if (trips)
> +		sysfs_notify(&tz->device.kobj, NULL, "temp");
>   }
>   EXPORT_SYMBOL_GPL(thermal_zone_device_update);
>
> @@ -1638,6 +1655,7 @@ void thermal_cdev_update(struct thermal_cooling_device *cdev)
>   	cdev->updated = true;
>   	trace_cdev_update(cdev, target);
>   	dev_dbg(&cdev->device, "set to state %lu\n", target);
> +	sysfs_notify(&cdev->device.kobj, NULL, "cur_state");
>   }
>   EXPORT_SYMBOL(thermal_cdev_update);
>
>
I intended this change to be an RFC and posted it by mistake. Kindly
ignore this patch. I sent it as a RFC again. Apologize for this
  duplicate email.
Srikar