Date:	Tue, 15 Oct 2013 19:03:28 +0800
From:	Zhang Rui <rui.zhang@...el.com>
To:	Durgadoss R <durgadoss.r@...el.com>
Cc:	eduardo.valentin@...com, linux-pm@...r.kernel.org,
	linux-kernel@...r.kernel.org, hongbo.zhang@...escale.com,
	wni@...dia.com
Subject: Re: [PATCHv4 5/9] Thermal: Add trip point sysfs nodes for sensor

On Wed, 2013-10-02 at 00:08 +0530, Durgadoss R wrote:
> This patch adds a trip point related sysfs nodes
> for each sensor under a zone in /sys/class/thermal/zoneX/.
> The nodes will be named, sensorX_trip_activeY,
> sensorX_trip_passiveY, sensorX_trip_hot, sensorX_trip_critical
> for active, passive, hot and critical trip points
> respectively for sensorX.
> 
> Signed-off-by: Durgadoss R <durgadoss.r@...el.com>
> ---
>  drivers/thermal/thermal_core.c |  344 +++++++++++++++++++++++++++++++++++++++-
>  include/linux/thermal.h        |   40 ++++-
>  2 files changed, 379 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
> index 3c4ef62..d6e29f6 100644
> --- a/drivers/thermal/thermal_core.c
> +++ b/drivers/thermal/thermal_core.c
> @@ -494,6 +494,60 @@ static void thermal_zone_device_check(struct work_struct *work)
>  	thermal_zone_device_update(tz);
>  }
>  
> +static int get_sensor_indx_by_kobj(struct thermal_zone *tz, const char *name)
> +{
> +	int i, indx = -EINVAL;
> +
> +	/* Protect against tz->sensors[i] being unregistered */
> +	mutex_lock(&sensor_list_lock);
> +
> +	for (i = 0; i < tz->sensor_indx; i++) {
> +		if (!strnicmp(name, kobject_name(&tz->sensors[i]->device.kobj),
> +					THERMAL_NAME_LENGTH)) {
> +			indx = i;
> +			break;
> +		}
> +	}
> +
> +	mutex_unlock(&sensor_list_lock);
> +	return indx;
> +}
> +
> +static void __remove_trip_attr(struct thermal_zone *tz, int indx)
> +{
> +	int i;
> +	struct thermal_trip_attr *attr = tz->trip_attr[indx];
> +	struct thermal_trip_point *trip = tz->sensor_trip[indx];
> +
> +	if (!attr || !trip)
> +		return;
> +
> +	if (trip->crit != THERMAL_TRIPS_NONE)
> +		device_remove_file(&tz->device, &attr->crit_attr.attr);
> +
> +	if (trip->hot != THERMAL_TRIPS_NONE)
> +		device_remove_file(&tz->device, &attr->hot_attr.attr);
> +
> +	if (trip->num_passive_trips > 0) {
> +		for (i = 0; i < trip->num_passive_trips; i++) {
> +			device_remove_file(&tz->device,
> +						&attr->passive_attrs[i].attr);
> +		}
> +		kfree(attr->passive_attrs);
> +	}
> +
> +	if (trip->num_active_trips > 0) {
> +		for (i = 0; i < trip->num_active_trips; i++) {
> +			device_remove_file(&tz->device,
> +						&attr->active_attrs[i].attr);
> +		}
> +		kfree(attr->active_attrs);
> +	}
> +
> +	kfree(tz->trip_attr[indx]);
> +	tz->trip_attr[indx] = NULL;
> +}
> +
>  static void remove_sensor_from_zone(struct thermal_zone *tz,
>  				struct thermal_sensor *ts)
>  {
> @@ -503,13 +557,19 @@ static void remove_sensor_from_zone(struct thermal_zone *tz,
>  	if (indx < 0)
>  		return;
>  
> -	sysfs_remove_link(&tz->device.kobj, kobject_name(&ts->device.kobj));
> -
>  	mutex_lock(&tz->lock);
>  
> +	/* Remove trip point attributes associated with this sensor */
> +	__remove_trip_attr(tz, indx);
> +
> +	sysfs_remove_link(&tz->device.kobj, kobject_name(&ts->device.kobj));
> +
>  	/* Shift the entries in the tz->sensors array */
> -	for (j = indx; j < MAX_SENSORS_PER_ZONE - 1; j++)
> +	for (j = indx; j < MAX_SENSORS_PER_ZONE - 1; j++) {
>  		tz->sensors[j] = tz->sensors[j + 1];
> +		tz->sensor_trip[j] = tz->sensor_trip[j + 1];
> +		tz->trip_attr[j] = tz->trip_attr[j + 1];
> +	}
>  
>  	tz->sensor_indx--;
>  	mutex_unlock(&tz->lock);
> @@ -952,6 +1012,111 @@ emul_temp_store(struct device *dev, struct device_attribute *attr,
>  static DEVICE_ATTR(emul_temp, S_IWUSR, NULL, emul_temp_store);
>  #endif/*CONFIG_THERMAL_EMULATION*/
>  
> +static ssize_t
> +active_trip_show(struct device *dev, struct device_attribute *attr, char *buf)
> +{
> +	int i, j, val;
> +	char kobj_name[THERMAL_NAME_LENGTH];
> +	struct thermal_zone *tz = to_zone(dev);
> +
> +	if (!sscanf(attr->attr.name, "sensor%d_trip_active%d", &i, &j))
> +		return -EINVAL;
> +
> +	snprintf(kobj_name, THERMAL_NAME_LENGTH, "sensor%d", i);
> +
> +	mutex_lock(&tz->lock);
> +
> +	i = get_sensor_indx_by_kobj(tz, kobj_name);
> +	if (i < 0) {
> +		mutex_unlock(&tz->lock);
> +		return i;
> +	}
> +
> +	val = tz->sensor_trip[i]->active_trips[j];
> +	mutex_unlock(&tz->lock);
> +
> +	return sprintf(buf, "%d\n", val);
> +}
> +
> +static ssize_t
> +passive_trip_show(struct device *dev, struct device_attribute *attr, char *buf)
> +{
> +	int i, j, val;
> +	char kobj_name[THERMAL_NAME_LENGTH];
> +	struct thermal_zone *tz = to_zone(dev);
> +
> +	if (!sscanf(attr->attr.name, "sensor%d_trip_passive%d", &i, &j))
> +		return -EINVAL;
> +
> +	snprintf(kobj_name, THERMAL_NAME_LENGTH, "sensor%d", i);
> +
> +	mutex_lock(&tz->lock);
> +
> +	i = get_sensor_indx_by_kobj(tz, kobj_name);
> +	if (i < 0) {
> +		mutex_unlock(&tz->lock);
> +		return i;
> +	}
> +
> +	val = tz->sensor_trip[i]->passive_trips[j];
> +	mutex_unlock(&tz->lock);
> +
> +	return sprintf(buf, "%d\n", val);
> +}
> +
> +static ssize_t
> +hot_trip_show(struct device *dev, struct device_attribute *attr, char *buf)
> +{
> +	int indx, val;
> +	char kobj_name[THERMAL_NAME_LENGTH];
> +	struct thermal_zone *tz = to_zone(dev);
> +
> +	if (!sscanf(attr->attr.name, "sensor%d_trip_hot", &indx))
> +		return -EINVAL;
> +
> +	snprintf(kobj_name, THERMAL_NAME_LENGTH, "sensor%d", indx);
> +
> +	mutex_lock(&tz->lock);
> +
> +	indx = get_sensor_indx_by_kobj(tz, kobj_name);
> +	if (indx < 0) {
> +		mutex_unlock(&tz->lock);
> +		return indx;
> +	}
> +
> +	val = tz->sensor_trip[indx]->hot;
> +	mutex_unlock(&tz->lock);
> +
> +	return sprintf(buf, "%d\n", val);
> +}
> +
> +static ssize_t
> +critical_trip_show(struct device *dev,
> +			struct device_attribute *attr, char *buf)
> +{
> +	int indx, val;
> +	char kobj_name[THERMAL_NAME_LENGTH];
> +	struct thermal_zone *tz = to_zone(dev);
> +
> +	if (!sscanf(attr->attr.name, "sensor%d_trip_critical", &indx))
> +		return -EINVAL;
> +
> +	snprintf(kobj_name, THERMAL_NAME_LENGTH, "sensor%d", indx);
> +
> +	mutex_lock(&tz->lock);
> +
> +	indx = get_sensor_indx_by_kobj(tz, kobj_name);
> +	if (indx < 0) {
> +		mutex_unlock(&tz->lock);
> +		return indx;
> +	}
> +
> +	val = tz->sensor_trip[indx]->crit;
> +	mutex_unlock(&tz->lock);
> +
> +	return sprintf(buf, "%d\n", val);
> +}
> +
>  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);
> @@ -962,7 +1127,8 @@ static DEVICE_ATTR(policy, S_IRUGO | S_IWUSR, policy_show, policy_store);
>  static DEVICE_ATTR(sensor_name, 0444, sensor_name_show, NULL);
>  static DEVICE_ATTR(temp_input, 0444, sensor_temp_show, NULL);
>  
> -static DEVICE_ATTR(zone_name, 0444, zone_name_show, NULL);
> +/* Thermal zone attributes */
> +static DEVICE_ATTR(zone_name, S_IRUGO, zone_name_show, NULL);
>  
>  /* sys I/F for cooling device */
>  #define to_cooling_device(_dev)	\
> @@ -1841,6 +2007,43 @@ static int enable_sensor_thresholds(struct thermal_sensor *ts, int count)
>  	return 0;
>  }
>  
> +static int create_single_trip_attr(struct thermal_zone *tz,
> +			struct thermal_attr *attr,
> +			const char *attr_name,
> +			ssize_t (*rd_ptr)(struct device *dev,
> +			struct device_attribute *devattr, char *buf))
> +{
> +	snprintf(attr->name, THERMAL_NAME_LENGTH, attr_name);
> +	sysfs_attr_init(&attr->attr.attr);
> +	attr->attr.attr.name = attr->name;
> +	attr->attr.attr.mode = S_IRUGO;
> +	attr->attr.show = rd_ptr;
> +	return device_create_file(&tz->device, &attr->attr);
> +}
> +
> +static int create_multi_trip_attrs(struct thermal_zone *tz, int size,
> +			int indx, struct thermal_attr *attrs,
> +			const char *attr_name,
> +			ssize_t (*rd_ptr)(struct device *dev,
> +			struct device_attribute *devattr, char *buf))
> +{
> +	char name[THERMAL_NAME_LENGTH];
> +	int i, ret;
> +
> +	for (i = 0; i < size; i++) {
> +		snprintf(name, THERMAL_NAME_LENGTH, attr_name, indx, i);
> +		ret = create_single_trip_attr(tz, &attrs[i], name, rd_ptr);
> +		if (ret)
> +			goto exit;
> +	}
> +	return 0;
> +
> +exit:
> +	while (--i >= 0)
> +		device_remove_file(&tz->device, &attrs[i].attr);
> +	return ret;
> +}
> +
>  /**
>   * create_thermal_zone - create sysfs nodes for thermal zone
>   * @name:	Name of the thermla zone
> @@ -2139,6 +2342,139 @@ exit_zone:
>  EXPORT_SYMBOL(add_cdev_to_zone);
>  
>  /**
> + * add_sensor_trip_info - Add trip point information for @ts in @tz
> + * @tz:		Thermal zone reference
> + * @ts:		Thermal sensor reference
> + * @trip:	Trip point structure reference
> + *
> + * Returns 0 on success, otherwise
> + * -EINVAL for invalid paramenters
> + * -EINVAL if @ts is not part of 'this' thermal zone @tz
> + * -ENOMEM on kzalloc failures
> + */
> +int add_sensor_trip_info(struct thermal_zone *tz, struct thermal_sensor *ts,
> +			struct thermal_trip_point *trip)
> +{
> +	char name[THERMAL_NAME_LENGTH];
> +	int i, indx, kobj_indx, ret, size;
> +	struct thermal_trip_attr *attrs;
> +
> +	if (!tz || !ts || !trip)
> +		return -EINVAL;
> +
> +	if (!sscanf(kobject_name(&ts->device.kobj), "sensor%d", &kobj_indx))
> +		return -EINVAL;
> +
> +	mutex_lock(&zone_list_lock);
> +
> +	indx = GET_INDEX(tz, ts, sensor);
> +	if (indx < 0) {
> +		ret = -EINVAL;
> +		goto exit;
> +	}
> +
> +	/* Protect against 'ts' being unregistered */
> +	mutex_lock(&sensor_list_lock);
> +
> +	/* Protect tz->trip_attr[] and tz->sensor_trip[] */
> +	mutex_lock(&tz->lock);
> +
> +	tz->trip_attr[indx] = kzalloc(sizeof(struct thermal_trip_attr),
> +					GFP_KERNEL);
> +	if (!tz->trip_attr[indx]) {
> +		ret = -ENOMEM;
> +		goto exit_lock;
> +	}
> +
> +	attrs = tz->trip_attr[indx];
> +
> +	/* Create Critical trip point attribute */
> +	if (trip->crit != THERMAL_TRIPS_NONE) {
> +		snprintf(name, THERMAL_NAME_LENGTH,
> +					"sensor%d_trip_critical", kobj_indx);
> +		ret = create_single_trip_attr(tz, &attrs->crit_attr,
> +					name, critical_trip_show);
> +		if (ret)
> +			goto exit_trip;
> +	}
> +
> +	/* Create Hot trip point attribute */
> +	if (trip->hot != THERMAL_TRIPS_NONE) {
> +		snprintf(name, THERMAL_NAME_LENGTH,
> +					"sensor%d_trip_hot", kobj_indx);
> +		ret = create_single_trip_attr(tz, &attrs->hot_attr,
> +					name, hot_trip_show);
> +		if (ret)
> +			goto exit_crit_trip;
> +	}
> +
> +	/* Create Passive trip point attributes */
> +	if (trip->num_passive_trips > 0) {
> +		size = sizeof(struct thermal_attr) * trip->num_passive_trips;
> +		attrs->passive_attrs = kzalloc(size, GFP_KERNEL);
> +		if (!attrs->passive_attrs) {
> +			ret = -ENOMEM;
> +			goto exit_hot_trip;
> +		}
> +
> +		ret = create_multi_trip_attrs(tz, trip->num_passive_trips,
> +					kobj_indx, attrs->passive_attrs,
> +					"sensor%d_trip_passive%d",

well, I do not think this is a good code style.
I prefer to create the attrs one by one, rather than passing this ugly
format string.
please use create_single_trip_attr() instead if you can not find a clean
way to do this.

thanks,
rui
> +					passive_trip_show);
> +		if (ret)
> +			goto exit_hot_trip;
> +	}
> +
> +	/* Create Active trip point attributes */
> +	if (trip->num_active_trips > 0) {
> +		size = sizeof(struct thermal_attr) * trip->num_active_trips;
> +		attrs->active_attrs = kzalloc(size, GFP_KERNEL);
> +		if (!attrs->active_attrs) {
> +			ret = -ENOMEM;
> +			goto exit_passive_trips;
> +		}
> +
> +		ret = create_multi_trip_attrs(tz, trip->num_active_trips,
> +					kobj_indx, attrs->active_attrs,
> +					"sensor%d_trip_active%d",
> +					active_trip_show);
> +		if (ret)
> +			goto exit_passive_trips;
> +	}
> +
> +	tz->sensor_trip[indx] = trip;
> +
> +	mutex_unlock(&tz->lock);
> +	mutex_unlock(&sensor_list_lock);
> +	mutex_unlock(&zone_list_lock);
> +
> +	return 0;
> +
> +exit_passive_trips:
> +	kfree(attrs->active_attrs);
> +	i = trip->num_passive_trips;
> +	while (--i >= 0)
> +		device_remove_file(&tz->device, &attrs->passive_attrs[i].attr);
> +exit_hot_trip:
> +	kfree(attrs->passive_attrs);
> +	if (trip->hot != THERMAL_TRIPS_NONE)
> +		device_remove_file(&tz->device, &attrs->hot_attr.attr);
> +exit_crit_trip:
> +	if (trip->crit != THERMAL_TRIPS_NONE)
> +		device_remove_file(&tz->device, &attrs->crit_attr.attr);
> +exit_trip:
> +	kfree(tz->trip_attr[indx]);
> +	tz->trip_attr[indx] = NULL;
> +exit_lock:
> +	mutex_unlock(&tz->lock);
> +	mutex_unlock(&sensor_list_lock);
> +exit:
> +	mutex_unlock(&zone_list_lock);
> +	return ret;
> +}
> +EXPORT_SYMBOL(add_sensor_trip_info);
> +
> +/**
>   * thermal_sensor_register - register a new thermal sensor
>   * @name:	name of the thermal sensor
>   * @count:	Number of thresholds supported by hardware
> diff --git a/include/linux/thermal.h b/include/linux/thermal.h
> index da7520c..f8de86d 100644
> --- a/include/linux/thermal.h
> +++ b/include/linux/thermal.h
> @@ -31,7 +31,7 @@
>  
>  #define THERMAL_TRIPS_NONE	-1
>  #define THERMAL_MAX_TRIPS	12
> -#define THERMAL_NAME_LENGTH	20
> +#define THERMAL_NAME_LENGTH	25
>  
>  /* invalid cooling state */
>  #define THERMAL_CSTATE_INVALID -1UL
> @@ -170,6 +170,37 @@ struct thermal_attr {
>  	char name[THERMAL_NAME_LENGTH];
>  };
>  
> +/*
> + * This structure defines the trip points for a sensor.
> + * The actual values for these trip points come from
> + * platform characterization. The thermal governors
> + * (either kernel or user space) may take appropriate
> + * actions when the sensors reach these trip points.
> + * See Documentation/thermal/sysfs-api2.txt for more details.
> + *
> + * As of now, For a particular sensor, we support:
> + * a) 1 hot trip point
> + * b) 1 critical trip point
> + * c) 'n' passive trip points
> + * d) 'm' active trip points
> + */
> +struct thermal_trip_point {
> +	int hot;
> +	int crit;
> +	int num_passive_trips;
> +	int *passive_trips;
> +	int num_active_trips;
> +	int *active_trips;
> +	int active_trip_mask;
> +};
> +
> +struct thermal_trip_attr {
> +	struct thermal_attr hot_attr;
> +	struct thermal_attr crit_attr;
> +	struct thermal_attr *active_attrs;
> +	struct thermal_attr *passive_attrs;
> +};
> +
>  struct thermal_sensor {
>  	char name[THERMAL_NAME_LENGTH];
>  	int id;
> @@ -229,6 +260,10 @@ struct thermal_zone {
>  	/* cdev level information */
>  	int cdev_indx; /* index into 'cdevs' array */
>  	struct thermal_cooling_device *cdevs[MAX_CDEVS_PER_ZONE];
> +
> +	/* Thermal sensors trip information */
> +	struct thermal_trip_point *sensor_trip[MAX_SENSORS_PER_ZONE];
> +	struct thermal_trip_attr *trip_attr[MAX_SENSORS_PER_ZONE];
>  };
>  
>  /* Structure that holds thermal governor information */
> @@ -309,6 +344,9 @@ struct thermal_sensor *get_sensor_by_name(const char *);
>  int add_cdev_to_zone(struct thermal_zone *, struct thermal_cooling_device *);
>  struct thermal_cooling_device *get_cdev_by_name(const char *);
>  
> +int add_sensor_trip_info(struct thermal_zone *, struct thermal_sensor *,
> +			struct thermal_trip_point *);
> +
>  #ifdef CONFIG_NET
>  extern int thermal_generate_netlink_event(struct thermal_zone_device *tz,
>  						enum events event);


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