Date:	Thu, 28 Feb 2013 15:51:22 -0400
From:	Eduardo Valentin <eduardo.valentin@...com>
To:	Durgadoss R <durgadoss.r@...el.com>
CC:	<rui.zhang@...el.com>, <linux-pm@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>, <hongbo.zhang@...aro.org>,
	<wni@...dia.com>
Subject: Re: [PATCH 4/8] Thermal: Add trip point sysfs nodes for sensor

Durga,


Same comments on patch 02/08 I want to rise here:
- Minors on strlcpy, snprintf, devm_ helpers
- documentation in the code for these helper functions and also better 
naming..


On 05-02-2013 06:46, 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_active,
> sensorX_trip_passive, 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_sys.c |  225 ++++++++++++++++++++++++++++++++++++++++-
>   include/linux/thermal.h       |   38 ++++++-
>   2 files changed, 260 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/thermal/thermal_sys.c b/drivers/thermal/thermal_sys.c
> index bf703b1..69a60a4 100644
> --- a/drivers/thermal/thermal_sys.c
> +++ b/drivers/thermal/thermal_sys.c
> @@ -452,6 +452,37 @@ 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;
> +
> +	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 inline __remove_trip_attr(struct thermal_zone *tz, int indx)
I believe the preferred format would be:

static inline void __remove_trip_attr(struct thermal_zone *tz, int indx)

> +{
> +	int i;
> +	struct thermal_trip_attr *attr = tz->trip_attr[indx];
> +
> +	if (!attr)
> +		return;
> +
> +	for (i = 0; i < NUM_TRIP_TYPES; i++)
> +		device_remove_file(&tz->device, &attr->attrs[i].attr);
> +
> +	kfree(tz->trip_attr[indx]);
> +	tz->trip_attr[indx] = NULL;
> +}
> +
>   static void remove_sensor_from_zone(struct thermal_zone *tz,
>   				struct thermal_sensor *ts)
>   {
> @@ -463,9 +494,15 @@ static void remove_sensor_from_zone(struct thermal_zone *tz,
>
>   	sysfs_remove_link(&tz->device.kobj, kobject_name(&ts->device.kobj));
>
> +	/* Remove trip point attributes associated with this sensor */
> +	__remove_trip_attr(tz, indx);
> +
>   	/* 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--;
>   }
> @@ -879,6 +916,99 @@ policy_show(struct device *dev, struct device_attribute *devattr, char *buf)
>   	return sprintf(buf, "%s\n", tz->governor->name);
>   }
>
> +static ssize_t
> +active_show(struct device *dev, struct device_attribute *attr, char *buf)
> +{
> +	int i, indx, ret = 0;
> +	char kobj_name[THERMAL_NAME_LENGTH];
> +	struct thermal_zone *tz = to_zone(dev);
> +
> +	if (!sscanf(attr->attr.name, "sensor%d_trip_active", &i))
> +		return -EINVAL;
> +
> +	snprintf(kobj_name, THERMAL_NAME_LENGTH, "sensor%d", i);
> +	indx = get_sensor_indx_by_kobj(tz, kobj_name);
> +	if (indx < 0)
> +		return indx;
> +
> +	if (tz->sensor_trip[indx]->num_active_trips <= 0)
> +		return sprintf(buf, "<Not available>\n");
> +
> +	ret += sprintf(buf, "0x%x", tz->sensor_trip[indx]->active_trip_mask);
> +	for (i = 0; i < tz->sensor_trip[indx]->num_active_trips; i++) {
> +		ret += sprintf(buf + ret, " %d",
> +			tz->sensor_trip[indx]->active_trips[i]);
> +	}
> +
> +	ret += sprintf(buf + ret, "\n");
> +	return ret;
> +}
> +

I believe the above function violates sysfs rules, no? Each and every 
file must contain only 1 value..

> +static ssize_t
> +ptrip_show(struct device *dev, struct device_attribute *attr, char *buf)
> +{
> +	int i, indx, ret = 0;
> +	char kobj_name[THERMAL_NAME_LENGTH];
> +	struct thermal_zone *tz = to_zone(dev);
> +
> +	if (!sscanf(attr->attr.name, "sensor%d_trip_passive", &i))
> +		return -EINVAL;
> +
> +	snprintf(kobj_name, THERMAL_NAME_LENGTH, "sensor%d", i);
> +	indx = get_sensor_indx_by_kobj(tz, kobj_name);
> +	if (indx < 0)
> +		return indx;
> +
> +	if (tz->sensor_trip[indx]->num_passive_trips <= 0)
> +		return sprintf(buf, "<Not available>\n");
> +
> +	for (i = 0; i < tz->sensor_trip[indx]->num_passive_trips; i++) {
> +		ret += sprintf(buf + ret, "%d ",
> +			tz->sensor_trip[indx]->passive_trips[i]);
> +	}
> +
> +	ret += sprintf(buf + ret, "\n");
> +	return ret;
> +}


ditto.

> +
> +static ssize_t
> +hot_show(struct device *dev, struct device_attribute *attr, char *buf)
> +{
> +	int indx;
> +	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);
> +
> +	indx = get_sensor_indx_by_kobj(tz, kobj_name);
> +	if (indx < 0)
> +		return indx;
> +
> +	return sprintf(buf, "%d\n", tz->sensor_trip[indx]->hot);
> +}
> +
> +static ssize_t
> +critical_show(struct device *dev, struct device_attribute *attr, char *buf)
> +{
> +	int indx;
> +	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);
> +
> +	indx = get_sensor_indx_by_kobj(tz, kobj_name);
> +	if (indx < 0)
> +		return indx;
> +
> +	return sprintf(buf, "%d\n", tz->sensor_trip[indx]->crit);
> +}
> +
>   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);
> @@ -889,7 +1019,8 @@ 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)	\
> @@ -1744,6 +1875,38 @@ static int enable_sensor_thresholds(struct thermal_sensor *ts, int count)
>   	return 0;
>   }
>
> +static int create_sensor_trip_attrs(struct thermal_zone *tz,
> +				struct thermal_trip_attr *attr, int indx)
> +{
> +	int i, ret;
> +	static const char *const names[NUM_TRIP_TYPES] = {
> +				"sensor%d_trip_active",
> +				"sensor%d_trip_passive",
> +				"sensor%d_trip_hot",
> +				"sensor%d_trip_critical",
> +				};
> +	static ssize_t (*const rd_ptr[NUM_TRIP_TYPES]) (struct device *dev,
> +			struct device_attribute *devattr, char *buf) = {
> +			active_show, ptrip_show, hot_show, critical_show};
> +
> +	for (i = 0; i < NUM_TRIP_TYPES; i++) {
> +		snprintf(attr->attrs[i].name, THERMAL_NAME_LENGTH, names[i],
> +			indx);
> +		sysfs_attr_init(&attr->attrs[i].attr.attr);
> +		attr->attrs[i].attr.attr.name = attr->attrs[i].name;
> +		attr->attrs[i].attr.attr.mode = S_IRUGO;
> +		attr->attrs[i].attr.show = rd_ptr[i];
> +		ret = device_create_file(&tz->device, &attr->attrs[i].attr);
> +		if (ret)
> +			goto exit;
> +	}
> +	return 0;
> +exit:
> +	while (--i >= 0)
> +		device_remove_file(&tz->device, &attr->attrs[i].attr);
> +	return ret;
> +}
> +
>   struct thermal_zone *create_thermal_zone(const char *name, void *devdata)
>   {
>   	struct thermal_zone *tz;
> @@ -1793,6 +1956,7 @@ EXPORT_SYMBOL(create_thermal_zone);
>   void remove_thermal_zone(struct thermal_zone *tz)
>   {
>   	struct thermal_zone *pos, *next;
> +	int i;
>   	bool found = false;
>
>   	if (!tz)
> @@ -1813,6 +1977,23 @@ void remove_thermal_zone(struct thermal_zone *tz)
>
>   	device_remove_file(&tz->device, &dev_attr_zone_name);
>
> +	/* Just for ease of usage */
> +	i = tz->sensor_indx;
> +	while (--i >= 0) {
> +		/* Remove /sys/class/thermal/zoneX/sensorY */
> +		sysfs_remove_link(&tz->device.kobj,
> +				kobject_name(&tz->sensors[i]->device.kobj));
> +		__remove_trip_attr(tz, i);
> +	}
> +
> +	/* Release the cdevs attached to this zone */
> +	i = tz->cdev_indx;
> +	while (--i >= 0) {
> +		/* Remove /sys/class/thermal/zoneX/cooling_deviceY */
> +		sysfs_remove_link(&tz->device.kobj,
> +				kobject_name(&tz->cdevs[i]->device.kobj));
> +	}
> +
>   	release_idr(&thermal_zone_idr, &thermal_idr_lock, tz->id);
>   	idr_destroy(&tz->idr);
>
> @@ -1924,6 +2105,46 @@ exit_zone:
>   }
>   EXPORT_SYMBOL(add_cdev_to_zone);
>
> +int add_sensor_trip_info(struct thermal_zone *tz, struct thermal_sensor *ts,
> +			struct thermal_trip_point *trip)
> +{
> +	int ret, indx, kobj_indx;
> +
> +	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;
> +	}
> +
> +	tz->trip_attr[indx] = kzalloc(sizeof(struct thermal_trip_attr),
> +					GFP_KERNEL);
> +	if (!tz->trip_attr[indx]) {
> +		ret = -ENOMEM;
> +		goto exit;
> +	}
> +
> +	ret = create_sensor_trip_attrs(tz, tz->trip_attr[indx], kobj_indx);
> +	if (ret) {
> +		kfree(tz->trip_attr[indx]);
> +		goto exit;
> +	}
> +
> +	tz->sensor_trip[indx] = trip;
> +
> +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
> diff --git a/include/linux/thermal.h b/include/linux/thermal.h
> index c841414..2f68018 100644
> --- a/include/linux/thermal.h
> +++ b/include/linux/thermal.h
> @@ -31,7 +31,8 @@
>
>   #define THERMAL_TRIPS_NONE	-1
>   #define THERMAL_MAX_TRIPS	12
> -#define THERMAL_NAME_LENGTH	20
> +#define THERMAL_NAME_LENGTH	22
> +#define NUM_TRIP_TYPES		4
>
>   /* No upper/lower limit requirement */
>   #define THERMAL_NO_LIMIT	-1UL
> @@ -166,6 +167,34 @@ 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 attrs[NUM_TRIP_TYPES];
> +};
> +
>   struct thermal_sensor {
>   	char name[THERMAL_NAME_LENGTH];
>   	int id;
> @@ -223,6 +252,10 @@ 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 */
> @@ -305,6 +338,9 @@ 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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