Re: [PATCH V2 1/2] thermal: sysfs: Add a new sysfs node emul_temp for thermal emulation

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On Sun, 2013-01-27 at 19:28 -0800, Amit Daniel Kachhap wrote:
> This patch adds support to set the emulated temperature method in
> thermal zone (sensor). After setting this feature thermal zone may
> report this temperature and not the actual temperature. The emulation
> implementation may be based on sensor capability through platform
> specific handler or pure software emulation if no platform handler defined.
> 
> This is useful in debugging different temperature threshold and its
> associated cooling action. Critical threshold's cannot be emulated.
> Writing 0 on this node should disable emulation.
> 
> Signed-off-by: Amit Daniel Kachhap <amit.daniel@xxxxxxxxxxx>
> Acked-by: Kukjin Kim <kgene.kim@xxxxxxxxxxx>
> ---
> 
> Changes in V2:
> * Added config option for enabling emulation support.
> * Added s/w emulation if no platform handler registered.
> * skip the critical trip point emulation
> 
> This patchset is based on thermal maintainer next tree.
> git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux.git next 
> 
>  Documentation/thermal/sysfs-api.txt |   13 ++++++
>  drivers/thermal/Kconfig             |    8 +++
>  drivers/thermal/thermal_sys.c       |   82 ++++++++++++++++++++++++++++++-----
>  include/linux/thermal.h             |    2 +
>  4 files changed, 94 insertions(+), 11 deletions(-)
> 
> diff --git a/Documentation/thermal/sysfs-api.txt b/Documentation/thermal/sysfs-api.txt
> index 526d4b9..6859661 100644
> --- a/Documentation/thermal/sysfs-api.txt
> +++ b/Documentation/thermal/sysfs-api.txt
> @@ -55,6 +55,8 @@ temperature) and throttle appropriate devices.
>  	.get_trip_type: get the type of certain trip point.
>  	.get_trip_temp: get the temperature above which the certain trip point
>  			will be fired.
> +	.set_emul_temp: set the emulation temperature which helps in debugging
> +			different threshold temperature points.
>  
>  1.1.2 void thermal_zone_device_unregister(struct thermal_zone_device *tz)
>  
> @@ -153,6 +155,7 @@ Thermal zone device sys I/F, created once it's registered:
>      |---trip_point_[0-*]_temp:	Trip point temperature
>      |---trip_point_[0-*]_type:	Trip point type
>      |---trip_point_[0-*]_hyst:	Hysteresis value for this trip point
> +    |---emul_temp:		Emulated temperature set node
>  
>  Thermal cooling device sys I/F, created once it's registered:
>  /sys/class/thermal/cooling_device[0-*]:
> @@ -252,6 +255,16 @@ passive
>  	Valid values: 0 (disabled) or greater than 1000
>  	RW, Optional
>  
> +emul_temp
> +	Interface to set the emulated temperature method in thermal zone
> +	(sensor). After setting this temperature, the thermal zone may pass
> +	this temperature to platform emulation function if registered or
> +	cache it locally. This is useful in debugging different temperature
> +	threshold and its associated cooling action. This is write only node
> +	and writing 0 on this node should disable emulation.
> +	Unit: millidegree Celsius
> +	WO, Optional
> +
>  *****************************
>  * Cooling device attributes *
>  *****************************
> diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
> index faf38c5..e4cf7fb 100644
> --- a/drivers/thermal/Kconfig
> +++ b/drivers/thermal/Kconfig
> @@ -78,6 +78,14 @@ config CPU_THERMAL
>  	  and not the ACPI interface.
>  	  If you want this support, you should say Y here.
>  
> +config THERMAL_EMULATION
> +	bool "Thermal emulation mode support"
> +	help
> +	  Enable this option to make a emul_temp sysfs node in thermal zone
> +	  directory to support temperature emulation. With emulation sysfs node,
> +	  user can manually input temperature and test the different trip
> +	  threshold behaviour for simulation purpose.
> +
>  config SPEAR_THERMAL
>  	bool "SPEAr thermal sensor driver"
>  	depends on PLAT_SPEAR
> diff --git a/drivers/thermal/thermal_sys.c b/drivers/thermal/thermal_sys.c
> index 0a1bf6b..59ba709 100644
> --- a/drivers/thermal/thermal_sys.c
> +++ b/drivers/thermal/thermal_sys.c
> @@ -378,24 +378,57 @@ static void handle_thermal_trip(struct thermal_zone_device *tz, int trip)
>  	monitor_thermal_zone(tz);
>  }
>  
> +static int thermal_zone_get_temp(struct thermal_zone_device *tz,
> +				unsigned long *temp)
> +{
> +	int ret = 0, count;
> +	unsigned long crit_temp = -1UL;
> +	enum thermal_trip_type type;
> +
> +	mutex_lock(&tz->lock);
> +
> +	if (tz->ops->get_temp)
> +		ret = tz->ops->get_temp(tz, temp);
we do not need to do this check, .get_temp() should always be available.

#ifdef CONFIG_THERMAL_EMUL
> +	else
> +		ret = -EPERM;
> +
> +	if (!tz->emul_temperature)
> +		goto skip_emul;
> +


> +	for (count = 0; count < tz->trips; count++) {
> +		ret = tz->ops->get_trip_type(tz, count, &type);
> +		if (!ret && type == THERMAL_TRIP_CRITICAL) {
> +			ret = tz->ops->get_trip_temp(tz, count, &crit_temp);
> +			break;
> +		}
> +	}
> +
> +	if (ret)
> +		goto skip_emul;
> +
> +	if (*temp < crit_temp)
> +		*temp = tz->emul_temperature;
> +
> +skip_emul:
#endif

or you can introduce get_emul_temp() instead.

> +	mutex_unlock(&tz->lock);
> +	return ret;
> +}
> +
>  static void update_temperature(struct thermal_zone_device *tz)
>  {
>  	long temp;
>  	int ret;
>  
> -	mutex_lock(&tz->lock);
> -
> -	ret = tz->ops->get_temp(tz, &temp);
> +	ret = thermal_zone_get_temp(tz, &temp);
>  	if (ret) {
>  		dev_warn(&tz->device, "failed to read out thermal zone %d\n",
>  			 tz->id);
> -		goto exit;
> +		return;
>  	}
>  
> +	mutex_lock(&tz->lock);
>  	tz->last_temperature = tz->temperature;
>  	tz->temperature = temp;
> -
> -exit:
>  	mutex_unlock(&tz->lock);
>  }
>  
> @@ -438,10 +471,7 @@ temp_show(struct device *dev, struct device_attribute *attr, char *buf)
>  	long temperature;
>  	int ret;
>  
> -	if (!tz->ops->get_temp)
> -		return -EPERM;
> -
> -	ret = tz->ops->get_temp(tz, &temperature);
> +	ret = thermal_zone_get_temp(tz, &temperature);
>  
>  	if (ret)
>  		return ret;
> @@ -701,6 +731,31 @@ policy_show(struct device *dev, struct device_attribute *devattr, char *buf)
>  	return sprintf(buf, "%s\n", tz->governor->name);
>  }
>  
> +#ifdef CONFIG_THERMAL_EMULATION
> +static ssize_t
> +emul_temp_store(struct device *dev, struct device_attribute *attr,
> +		     const char *buf, size_t count)
> +{
> +	struct thermal_zone_device *tz = to_thermal_zone(dev);
> +	int ret = 0;
> +	unsigned long temperature;
> +
> +	if (kstrtoul(buf, 10, &temperature))
> +		return -EINVAL;
> +
> +	if (!tz->ops->set_emul_temp) {
> +		mutex_lock(&tz->lock);
> +		tz->emul_temperature = temperature;
> +		mutex_unlock(&tz->lock);
> +	} else {
> +		ret = tz->ops->set_emul_temp(tz, temperature);
> +	}
> +
> +	return ret ? ret : count;
> +}
> +static DEVICE_ATTR(emul_temp, S_IWUSR, NULL, emul_temp_store);
> +#endif/*CONFIG_THERMAL_EMULATION*/
> +
>  static DEVICE_ATTR(type, 0444, type_show, NULL);
>  static DEVICE_ATTR(temp, 0444, temp_show, NULL);
>  static DEVICE_ATTR(mode, 0644, mode_show, mode_store);
> @@ -843,7 +898,7 @@ temp_input_show(struct device *dev, struct device_attribute *attr, char *buf)
>  				       temp_input);
>  	struct thermal_zone_device *tz = temp->tz;
>  
> -	ret = tz->ops->get_temp(tz, &temperature);
> +	ret = thermal_zone_get_temp(tz, &temperature);
>  
>  	if (ret)
>  		return ret;
> @@ -1596,6 +1651,11 @@ struct thermal_zone_device *thermal_zone_device_register(const char *type,
>  			goto unregister;
>  	}
>  
> +#ifdef CONFIG_THERMAL_EMULATION
> +	result = device_create_file(&tz->device, &dev_attr_emul_temp);
> +	if (result)
> +		goto unregister;
> +#endif
>  	/* Create policy attribute */
>  	result = device_create_file(&tz->device, &dev_attr_policy);
>  	if (result)
> diff --git a/include/linux/thermal.h b/include/linux/thermal.h
> index 9b78f8c..f0bd7f9 100644
> --- a/include/linux/thermal.h
> +++ b/include/linux/thermal.h
> @@ -123,6 +123,7 @@ struct thermal_zone_device_ops {
>  	int (*set_trip_hyst) (struct thermal_zone_device *, int,
>  			      unsigned long);
>  	int (*get_crit_temp) (struct thermal_zone_device *, unsigned long *);
> +	int (*set_emul_temp) (struct thermal_zone_device *, unsigned long);
>  	int (*get_trend) (struct thermal_zone_device *, int,
>  			  enum thermal_trend *);
>  	int (*notify) (struct thermal_zone_device *, int,
> @@ -165,6 +166,7 @@ struct thermal_zone_device {
>  	int polling_delay;
>  	int temperature;
>  	int last_temperature;
> +	int emul_temperature;
>  	int passive;
>  	unsigned int forced_passive;
>  	const struct thermal_zone_device_ops *ops;
others look okay to me.

thanks,
rui


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