[RFC,4/7] Thermal: Add Thermal_trip sysfs node
diff mbox

Message ID 1353149158-19102-5-git-send-email-durgadoss.r@intel.com
State Not Applicable, archived
Delegated to: Zhang Rui
Headers show

Commit Message

durgadoss.r@intel.com Nov. 17, 2012, 10:45 a.m. UTC
This patch adds a thermal_trip directory under
/sys/class/thermal/zoneX. This directory contains
the trip point values for sensors bound to this
zone.

Signed-off-by: Durgadoss R <durgadoss.r@intel.com>
---
 drivers/thermal/thermal_sys.c |  244 ++++++++++++++++++++++++++++++++++++++++-
 include/linux/thermal.h       |   32 ++++++
 2 files changed, 274 insertions(+), 2 deletions(-)

Comments

Hongbo Zhang Dec. 4, 2012, 8:30 a.m. UTC | #1
On 17 November 2012 18:45, Durgadoss R <durgadoss.r@intel.com> wrote:
> This patch adds a thermal_trip directory under
> /sys/class/thermal/zoneX. This directory contains
> the trip point values for sensors bound to this
> zone.
>
> Signed-off-by: Durgadoss R <durgadoss.r@intel.com>
> ---
>  drivers/thermal/thermal_sys.c |  244 ++++++++++++++++++++++++++++++++++++++++-
>  include/linux/thermal.h       |   32 ++++++
>  2 files changed, 274 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/thermal/thermal_sys.c b/drivers/thermal/thermal_sys.c
> index 70e5f5a..011588a 100644
> --- a/drivers/thermal/thermal_sys.c
> +++ b/drivers/thermal/thermal_sys.c
> @@ -480,9 +480,15 @@ static void remove_sensor_from_zone(struct thermal_zone *tz,
>
>         sysfs_remove_link(&tz->device.kobj, kobject_name(&ts->device.kobj));
>
> +       /* Delete this sensor's trip Kobject */
> +       kobject_del(tz->kobj_trip[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->trip[j] = tz->trip[j + 1];
> +               tz->kobj_trip[j] = tz->kobj_trip[j + 1];
> +       }
>
>         tz->sensor_indx--;
>  }
> @@ -505,6 +511,41 @@ static void remove_cdev_from_zone(struct thermal_zone *tz,
>         tz->cdev_indx--;
>  }
>
> +static struct thermal_zone *get_zone_by_trip_kobj(struct kobject *kobj)
> +{
> +       struct thermal_zone *pos;
> +       struct thermal_zone *tz = NULL;
> +
> +       if (!kobj)
> +               return NULL;
> +
> +       mutex_lock(&tz_list_lock);
> +       for_each_thermal_zone(pos) {
> +               if (pos->kobj_thermal_trip == kobj) {
> +                       tz = pos;
> +                       break;
> +               }
> +       }
> +       mutex_unlock(&tz_list_lock);
> +       return tz;
> +}
> +
> +static struct thermal_sensor *get_sensor_by_kobj_name(const char *name)
> +{
> +       struct thermal_sensor *pos;
> +       struct thermal_sensor *ts = NULL;
> +
> +       mutex_lock(&ts_list_lock);
> +       for_each_thermal_sensor(pos) {
> +               if (!strcmp(kobject_name(&pos->device.kobj), name)) {
> +                       ts = pos;
> +                       break;
> +               }
> +       }
> +       mutex_unlock(&ts_list_lock);
> +       return ts;
> +}
> +
>  /* sys I/F for thermal zone */
>
>  #define to_thermal_zone(_dev) \
> @@ -859,6 +900,113 @@ 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 kobject *kobj, struct kobj_attribute *attr, char *buf)
> +{
> +       int i, indx, ret = 0;
> +       struct thermal_sensor *ts;
> +       struct thermal_zone *tz;
> +
> +       ts = get_sensor_by_kobj_name(kobject_name(kobj));
> +       if (!ts)
> +               return -EINVAL;
> +
> +       tz = get_zone_by_trip_kobj(kobj->parent);
> +       if (!tz)
> +               return -EINVAL;
> +
> +       indx = get_sensor_indx(tz, ts);
> +       if (indx < 0)
> +               return indx;
> +
> +       if (tz->trip[indx]->num_active_trips <= 0)
> +               return sprintf(buf, "<Not available>\n");
> +
> +       ret += sprintf(buf, "0x%x", tz->trip[indx]->active_trip_mask);
> +       for (i = 0; i < tz->trip[indx]->num_active_trips; i++) {
> +               ret += sprintf(buf + ret, " %d",
> +                       tz->trip[indx]->active_trips[i]);
> +       }
> +
> +       ret += sprintf(buf + ret, "\n");
> +       return ret;
> +}
> +
> +static ssize_t
> +ptrip_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
Just remind you it is better to use passive_show instead of ptrip_show
when you remove the unused old codes.

> +{
> +       int i, indx, ret = 0;
> +       struct thermal_sensor *ts;
> +       struct thermal_zone *tz;
> +
> +       ts = get_sensor_by_kobj_name(kobject_name(kobj));
> +       if (!ts)
> +               return -EINVAL;
> +
> +       tz = get_zone_by_trip_kobj(kobj->parent);
> +       if (!tz)
> +               return -EINVAL;
> +
> +       indx = get_sensor_indx(tz, ts);
> +       if (indx < 0)
> +               return indx;
> +
> +       if (tz->trip[indx]->num_passive_trips <= 0)
> +               return sprintf(buf, "<Not available>\n");
> +
> +       for (i = 0; i < tz->trip[indx]->num_passive_trips; i++) {
> +               ret += sprintf(buf + ret, "%d ",
> +                       tz->trip[indx]->passive_trips[i]);
> +       }
> +
> +       ret += sprintf(buf + ret, "\n");
> +       return ret;
> +}
> +
> +static ssize_t
> +hot_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
> +{
> +       int indx;
> +       struct thermal_sensor *ts;
> +       struct thermal_zone *tz;
> +
> +       ts = get_sensor_by_kobj_name(kobject_name(kobj));
> +       if (!ts)
> +               return -EINVAL;
> +
> +       tz = get_zone_by_trip_kobj(kobj->parent);
> +       if (!tz)
> +               return -EINVAL;
> +
> +       indx = get_sensor_indx(tz, ts);
> +       if (indx < 0)
> +               return indx;
> +
> +       return sprintf(buf, "%d\n", tz->trip[indx]->hot);
> +}
> +
> +static ssize_t
> +critical_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
> +{
> +       int indx;
> +       struct thermal_sensor *ts;
> +       struct thermal_zone *tz;
> +
> +       ts = get_sensor_by_kobj_name(kobject_name(kobj));
> +       if (!ts)
> +               return -EINVAL;
> +
> +       tz = get_zone_by_trip_kobj(kobj->parent);
> +       if (!tz)
> +               return -EINVAL;
> +
> +       indx = get_sensor_indx(tz, ts);
> +       if (indx < 0)
> +               return indx;
> +
> +       return sprintf(buf, "%d\n", tz->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);
> @@ -869,7 +1017,26 @@ 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);
> +
> +/* Thermal trip attributes */
> +static struct kobj_attribute active_attr = __ATTR_RO(active);
> +static struct kobj_attribute passive_attr = __ATTR_RO(ptrip);
> +static struct kobj_attribute hot_attr = __ATTR_RO(hot);
> +static struct kobj_attribute crit_attr = __ATTR_RO(critical);
> +
> +static struct attribute *trip_attrs[] = {
> +                       &active_attr.attr,
> +                       &passive_attr.attr,
> +                       &hot_attr.attr,
> +                       &crit_attr.attr,
> +                       NULL,
> +                       };
> +
> +static struct attribute_group trip_attr_group = {
> +                       .attrs = trip_attrs,
> +                       };
>
>  /* sys I/F for cooling device */
>  #define to_cooling_device(_dev)        \
> @@ -1694,12 +1861,19 @@ struct thermal_zone *create_thermal_zone(const char *name, void *devdata)
>         if (ret)
>                 goto exit_unregister;
>
> +       tz->kobj_thermal_trip = kobject_create_and_add("thermal_trip",
> +                                       &tz->device.kobj);
> +       if (!tz->kobj_thermal_trip)
> +               goto exit_name;
> +
>         /* Add this zone to the global list of thermal zones */
>         mutex_lock(&tz_list_lock);
>         list_add_tail(&tz->node, &thermal_zone_list);
>         mutex_unlock(&tz_list_lock);
>         return tz;
>
> +exit_name:
> +       device_remove_file(&tz->device, &dev_attr_zone_name);
>  exit_unregister:
>         device_unregister(&tz->device);
>  exit_idr:
> @@ -1713,6 +1887,7 @@ 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)
> @@ -1733,6 +1908,29 @@ 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) {
> +               sysfs_remove_link(&tz->device.kobj,
> +                               kobject_name(&tz->sensors[i]->device.kobj));
> +               if (tz->kobj_trip[i])
> +                       kobject_del(tz->kobj_trip[i]);
> +       }
> +
> +       if (tz->kobj_thermal_trip)
> +               kobject_del(tz->kobj_thermal_trip);
> +
> +       /* Release the cdevs attached to this zone */
> +       i = tz->cdev_indx;
> +
> +       while (--i >= 0) {
> +               sysfs_remove_link(&tz->device.kobj,
> +                               kobject_name(&tz->cdevs[i]->device.kobj));
> +       }
> +
> +       tz->sensor_indx = tz->cdev_indx = 0;
> +
>         release_idr(&thermal_zone_idr, &thermal_idr_lock, tz->id);
>         idr_destroy(&tz->idr);
>
> @@ -1864,6 +2062,48 @@ int add_cdev_to_zone(struct thermal_zone *tz,
>  }
>  EXPORT_SYMBOL(add_cdev_to_zone);
>
> +int add_sensor_trip_info(struct thermal_zone *tz, const char *sensor_name,
> +                       struct thermal_trip_point *trip)
> +{
> +       int indx, ret = -EINVAL;
> +       struct thermal_sensor *ts = get_sensor_by_name(sensor_name);
> +
> +       if (!tz || !ts || !trip)
> +               return ret;
> +
> +       mutex_lock(&tz_list_lock);
> +
> +       indx = get_sensor_indx(tz, ts);
> +       if (indx < 0)
> +               goto exit_indx;
> +
> +       tz->kobj_trip[indx] = kobject_create_and_add(
> +                                       kobject_name(&ts->device.kobj),
> +                                       tz->kobj_thermal_trip);
> +       if (!tz->kobj_trip[indx]) {
> +               ret = -ENOMEM;
> +               goto exit_indx;
> +       }
> +
> +       ret = sysfs_create_group(tz->kobj_trip[indx], &trip_attr_group);
> +       if (ret) {
> +               dev_err(&tz->device, "sysfs_create_group failed:%d\n", ret);
> +               goto exit_kobj;
> +       }
> +
> +       tz->trip[indx] = trip;
> +       mutex_unlock(&tz_list_lock);
> +       return 0;
> +
> +exit_kobj:
> +       kobject_del(tz->kobj_trip[indx]);
> +       tz->kobj_trip[indx] = NULL;
> +exit_indx:
> +       mutex_unlock(&tz_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 2913910..7b2fe35 100644
> --- a/include/linux/thermal.h
> +++ b/include/linux/thermal.h
> @@ -159,6 +159,30 @@ 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_sensor {
>         char name[THERMAL_NAME_LENGTH];
>         int id;
> @@ -215,6 +239,11 @@ struct thermal_zone {
>         /* cdev level information */
>         int cdev_indx; /* index into 'cdevs' array */
>         struct thermal_cooling_device *cdevs[MAX_CDEVS_PER_ZONE];
> +
> +       /* Thermal trip information */
> +       struct thermal_trip_point *trip[MAX_SENSORS_PER_ZONE];
> +       struct kobject *kobj_trip[MAX_SENSORS_PER_ZONE];
> +       struct kobject *kobj_thermal_trip;
>  };
>
>  /* Structure that holds thermal governor information */
> @@ -298,6 +327,9 @@ int add_sensor_to_zone_by_name(struct thermal_zone *, const char *);
>  int add_cdev_to_zone(struct thermal_zone *, struct thermal_cooling_device *);
>  int add_cdev_to_zone_by_name(struct thermal_zone *, const char *);
>
> +int add_sensor_trip_info(struct thermal_zone *, const char *,
> +                       struct thermal_trip_point *);
> +
>  #ifdef CONFIG_NET
>  extern int thermal_generate_netlink_event(u32 orig, enum events event);
>  #else
> --
> 1.7.9.5
>
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durgadoss.r@intel.com Dec. 4, 2012, 8:41 a.m. UTC | #2
> -----Original Message-----
> From: Hongbo Zhang [mailto:hongbo.zhang@linaro.org]
> Sent: Tuesday, December 04, 2012 2:01 PM
> To: R, Durgadoss
> Cc: Zhang, Rui; linux-pm@vger.kernel.org; wni@nvidia.com;
> eduardo.valentin@ti.com; amit.kachhap@linaro.org;
> sachin.kamat@linaro.org
> Subject: Re: [RFC PATCH 4/7] Thermal: Add Thermal_trip sysfs node
> 
> On 17 November 2012 18:45, Durgadoss R <durgadoss.r@intel.com> wrote:
> > This patch adds a thermal_trip directory under
> > /sys/class/thermal/zoneX. This directory contains
> > the trip point values for sensors bound to this
> > zone.
> >
> > Signed-off-by: Durgadoss R <durgadoss.r@intel.com>
> > ---
> >  drivers/thermal/thermal_sys.c |  244
> ++++++++++++++++++++++++++++++++++++++++-
> >  include/linux/thermal.h       |   32 ++++++
> >  2 files changed, 274 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/thermal/thermal_sys.c b/drivers/thermal/thermal_sys.c
> > index 70e5f5a..011588a 100644
> > --- a/drivers/thermal/thermal_sys.c
> > +++ b/drivers/thermal/thermal_sys.c
> > @@ -480,9 +480,15 @@ static void remove_sensor_from_zone(struct
> thermal_zone *tz,
> >
> >         sysfs_remove_link(&tz->device.kobj, kobject_name(&ts-
> >device.kobj));
> >
> > +       /* Delete this sensor's trip Kobject */
> > +       kobject_del(tz->kobj_trip[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->trip[j] = tz->trip[j + 1];
> > +               tz->kobj_trip[j] = tz->kobj_trip[j + 1];
> > +       }
> >
> >         tz->sensor_indx--;
> >  }
> > @@ -505,6 +511,41 @@ static void remove_cdev_from_zone(struct
> thermal_zone *tz,
> >         tz->cdev_indx--;
> >  }
> >
> > +static struct thermal_zone *get_zone_by_trip_kobj(struct kobject *kobj)
> > +{
> > +       struct thermal_zone *pos;
> > +       struct thermal_zone *tz = NULL;
> > +
> > +       if (!kobj)
> > +               return NULL;
> > +
> > +       mutex_lock(&tz_list_lock);
> > +       for_each_thermal_zone(pos) {
> > +               if (pos->kobj_thermal_trip == kobj) {
> > +                       tz = pos;
> > +                       break;
> > +               }
> > +       }
> > +       mutex_unlock(&tz_list_lock);
> > +       return tz;
> > +}
> > +
> > +static struct thermal_sensor *get_sensor_by_kobj_name(const char
> *name)
> > +{
> > +       struct thermal_sensor *pos;
> > +       struct thermal_sensor *ts = NULL;
> > +
> > +       mutex_lock(&ts_list_lock);
> > +       for_each_thermal_sensor(pos) {
> > +               if (!strcmp(kobject_name(&pos->device.kobj), name)) {
> > +                       ts = pos;
> > +                       break;
> > +               }
> > +       }
> > +       mutex_unlock(&ts_list_lock);
> > +       return ts;
> > +}
> > +
> >  /* sys I/F for thermal zone */
> >
> >  #define to_thermal_zone(_dev) \
> > @@ -859,6 +900,113 @@ 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 kobject *kobj, struct kobj_attribute *attr, char *buf)
> > +{
> > +       int i, indx, ret = 0;
> > +       struct thermal_sensor *ts;
> > +       struct thermal_zone *tz;
> > +
> > +       ts = get_sensor_by_kobj_name(kobject_name(kobj));
> > +       if (!ts)
> > +               return -EINVAL;
> > +
> > +       tz = get_zone_by_trip_kobj(kobj->parent);
> > +       if (!tz)
> > +               return -EINVAL;
> > +
> > +       indx = get_sensor_indx(tz, ts);
> > +       if (indx < 0)
> > +               return indx;
> > +
> > +       if (tz->trip[indx]->num_active_trips <= 0)
> > +               return sprintf(buf, "<Not available>\n");
> > +
> > +       ret += sprintf(buf, "0x%x", tz->trip[indx]->active_trip_mask);
> > +       for (i = 0; i < tz->trip[indx]->num_active_trips; i++) {
> > +               ret += sprintf(buf + ret, " %d",
> > +                       tz->trip[indx]->active_trips[i]);
> > +       }
> > +
> > +       ret += sprintf(buf + ret, "\n");
> > +       return ret;
> > +}
> > +
> > +static ssize_t
> > +ptrip_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
> Just remind you it is better to use passive_show instead of ptrip_show
> when you remove the unused old codes.

Yes, you told the reason also :-)
I did that because we have another function named passive_show.
So, when we remove the old code, we will change this name also :-)

Thanks,
Durga
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Patch
diff mbox

diff --git a/drivers/thermal/thermal_sys.c b/drivers/thermal/thermal_sys.c
index 70e5f5a..011588a 100644
--- a/drivers/thermal/thermal_sys.c
+++ b/drivers/thermal/thermal_sys.c
@@ -480,9 +480,15 @@  static void remove_sensor_from_zone(struct thermal_zone *tz,
 
 	sysfs_remove_link(&tz->device.kobj, kobject_name(&ts->device.kobj));
 
+	/* Delete this sensor's trip Kobject */
+	kobject_del(tz->kobj_trip[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->trip[j] = tz->trip[j + 1];
+		tz->kobj_trip[j] = tz->kobj_trip[j + 1];
+	}
 
 	tz->sensor_indx--;
 }
@@ -505,6 +511,41 @@  static void remove_cdev_from_zone(struct thermal_zone *tz,
 	tz->cdev_indx--;
 }
 
+static struct thermal_zone *get_zone_by_trip_kobj(struct kobject *kobj)
+{
+	struct thermal_zone *pos;
+	struct thermal_zone *tz = NULL;
+
+	if (!kobj)
+		return NULL;
+
+	mutex_lock(&tz_list_lock);
+	for_each_thermal_zone(pos) {
+		if (pos->kobj_thermal_trip == kobj) {
+			tz = pos;
+			break;
+		}
+	}
+	mutex_unlock(&tz_list_lock);
+	return tz;
+}
+
+static struct thermal_sensor *get_sensor_by_kobj_name(const char *name)
+{
+	struct thermal_sensor *pos;
+	struct thermal_sensor *ts = NULL;
+
+	mutex_lock(&ts_list_lock);
+	for_each_thermal_sensor(pos) {
+		if (!strcmp(kobject_name(&pos->device.kobj), name)) {
+			ts = pos;
+			break;
+		}
+	}
+	mutex_unlock(&ts_list_lock);
+	return ts;
+}
+
 /* sys I/F for thermal zone */
 
 #define to_thermal_zone(_dev) \
@@ -859,6 +900,113 @@  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 kobject *kobj, struct kobj_attribute *attr, char *buf)
+{
+	int i, indx, ret = 0;
+	struct thermal_sensor *ts;
+	struct thermal_zone *tz;
+
+	ts = get_sensor_by_kobj_name(kobject_name(kobj));
+	if (!ts)
+		return -EINVAL;
+
+	tz = get_zone_by_trip_kobj(kobj->parent);
+	if (!tz)
+		return -EINVAL;
+
+	indx = get_sensor_indx(tz, ts);
+	if (indx < 0)
+		return indx;
+
+	if (tz->trip[indx]->num_active_trips <= 0)
+		return sprintf(buf, "<Not available>\n");
+
+	ret += sprintf(buf, "0x%x", tz->trip[indx]->active_trip_mask);
+	for (i = 0; i < tz->trip[indx]->num_active_trips; i++) {
+		ret += sprintf(buf + ret, " %d",
+			tz->trip[indx]->active_trips[i]);
+	}
+
+	ret += sprintf(buf + ret, "\n");
+	return ret;
+}
+
+static ssize_t
+ptrip_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
+{
+	int i, indx, ret = 0;
+	struct thermal_sensor *ts;
+	struct thermal_zone *tz;
+
+	ts = get_sensor_by_kobj_name(kobject_name(kobj));
+	if (!ts)
+		return -EINVAL;
+
+	tz = get_zone_by_trip_kobj(kobj->parent);
+	if (!tz)
+		return -EINVAL;
+
+	indx = get_sensor_indx(tz, ts);
+	if (indx < 0)
+		return indx;
+
+	if (tz->trip[indx]->num_passive_trips <= 0)
+		return sprintf(buf, "<Not available>\n");
+
+	for (i = 0; i < tz->trip[indx]->num_passive_trips; i++) {
+		ret += sprintf(buf + ret, "%d ",
+			tz->trip[indx]->passive_trips[i]);
+	}
+
+	ret += sprintf(buf + ret, "\n");
+	return ret;
+}
+
+static ssize_t
+hot_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
+{
+	int indx;
+	struct thermal_sensor *ts;
+	struct thermal_zone *tz;
+
+	ts = get_sensor_by_kobj_name(kobject_name(kobj));
+	if (!ts)
+		return -EINVAL;
+
+	tz = get_zone_by_trip_kobj(kobj->parent);
+	if (!tz)
+		return -EINVAL;
+
+	indx = get_sensor_indx(tz, ts);
+	if (indx < 0)
+		return indx;
+
+	return sprintf(buf, "%d\n", tz->trip[indx]->hot);
+}
+
+static ssize_t
+critical_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
+{
+	int indx;
+	struct thermal_sensor *ts;
+	struct thermal_zone *tz;
+
+	ts = get_sensor_by_kobj_name(kobject_name(kobj));
+	if (!ts)
+		return -EINVAL;
+
+	tz = get_zone_by_trip_kobj(kobj->parent);
+	if (!tz)
+		return -EINVAL;
+
+	indx = get_sensor_indx(tz, ts);
+	if (indx < 0)
+		return indx;
+
+	return sprintf(buf, "%d\n", tz->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);
@@ -869,7 +1017,26 @@  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);
+
+/* Thermal trip attributes */
+static struct kobj_attribute active_attr = __ATTR_RO(active);
+static struct kobj_attribute passive_attr = __ATTR_RO(ptrip);
+static struct kobj_attribute hot_attr = __ATTR_RO(hot);
+static struct kobj_attribute crit_attr = __ATTR_RO(critical);
+
+static struct attribute *trip_attrs[] = {
+			&active_attr.attr,
+			&passive_attr.attr,
+			&hot_attr.attr,
+			&crit_attr.attr,
+			NULL,
+			};
+
+static struct attribute_group trip_attr_group = {
+			.attrs = trip_attrs,
+			};
 
 /* sys I/F for cooling device */
 #define to_cooling_device(_dev)	\
@@ -1694,12 +1861,19 @@  struct thermal_zone *create_thermal_zone(const char *name, void *devdata)
 	if (ret)
 		goto exit_unregister;
 
+	tz->kobj_thermal_trip = kobject_create_and_add("thermal_trip",
+					&tz->device.kobj);
+	if (!tz->kobj_thermal_trip)
+		goto exit_name;
+
 	/* Add this zone to the global list of thermal zones */
 	mutex_lock(&tz_list_lock);
 	list_add_tail(&tz->node, &thermal_zone_list);
 	mutex_unlock(&tz_list_lock);
 	return tz;
 
+exit_name:
+	device_remove_file(&tz->device, &dev_attr_zone_name);
 exit_unregister:
 	device_unregister(&tz->device);
 exit_idr:
@@ -1713,6 +1887,7 @@  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)
@@ -1733,6 +1908,29 @@  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) {
+		sysfs_remove_link(&tz->device.kobj,
+				kobject_name(&tz->sensors[i]->device.kobj));
+		if (tz->kobj_trip[i])
+			kobject_del(tz->kobj_trip[i]);
+	}
+
+	if (tz->kobj_thermal_trip)
+		kobject_del(tz->kobj_thermal_trip);
+
+	/* Release the cdevs attached to this zone */
+	i = tz->cdev_indx;
+
+	while (--i >= 0) {
+		sysfs_remove_link(&tz->device.kobj,
+				kobject_name(&tz->cdevs[i]->device.kobj));
+	}
+
+	tz->sensor_indx = tz->cdev_indx = 0;
+
 	release_idr(&thermal_zone_idr, &thermal_idr_lock, tz->id);
 	idr_destroy(&tz->idr);
 
@@ -1864,6 +2062,48 @@  int add_cdev_to_zone(struct thermal_zone *tz,
 }
 EXPORT_SYMBOL(add_cdev_to_zone);
 
+int add_sensor_trip_info(struct thermal_zone *tz, const char *sensor_name,
+			struct thermal_trip_point *trip)
+{
+	int indx, ret = -EINVAL;
+	struct thermal_sensor *ts = get_sensor_by_name(sensor_name);
+
+	if (!tz || !ts || !trip)
+		return ret;
+
+	mutex_lock(&tz_list_lock);
+
+	indx = get_sensor_indx(tz, ts);
+	if (indx < 0)
+		goto exit_indx;
+
+	tz->kobj_trip[indx] = kobject_create_and_add(
+					kobject_name(&ts->device.kobj),
+					tz->kobj_thermal_trip);
+	if (!tz->kobj_trip[indx]) {
+		ret = -ENOMEM;
+		goto exit_indx;
+	}
+
+	ret = sysfs_create_group(tz->kobj_trip[indx], &trip_attr_group);
+	if (ret) {
+		dev_err(&tz->device, "sysfs_create_group failed:%d\n", ret);
+		goto exit_kobj;
+	}
+
+	tz->trip[indx] = trip;
+	mutex_unlock(&tz_list_lock);
+	return 0;
+
+exit_kobj:
+	kobject_del(tz->kobj_trip[indx]);
+	tz->kobj_trip[indx] = NULL;
+exit_indx:
+	mutex_unlock(&tz_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 2913910..7b2fe35 100644
--- a/include/linux/thermal.h
+++ b/include/linux/thermal.h
@@ -159,6 +159,30 @@  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_sensor {
 	char name[THERMAL_NAME_LENGTH];
 	int id;
@@ -215,6 +239,11 @@  struct thermal_zone {
 	/* cdev level information */
 	int cdev_indx; /* index into 'cdevs' array */
 	struct thermal_cooling_device *cdevs[MAX_CDEVS_PER_ZONE];
+
+	/* Thermal trip information */
+	struct thermal_trip_point *trip[MAX_SENSORS_PER_ZONE];
+	struct kobject *kobj_trip[MAX_SENSORS_PER_ZONE];
+	struct kobject *kobj_thermal_trip;
 };
 
 /* Structure that holds thermal governor information */
@@ -298,6 +327,9 @@  int add_sensor_to_zone_by_name(struct thermal_zone *, const char *);
 int add_cdev_to_zone(struct thermal_zone *, struct thermal_cooling_device *);
 int add_cdev_to_zone_by_name(struct thermal_zone *, const char *);
 
+int add_sensor_trip_info(struct thermal_zone *, const char *,
+			struct thermal_trip_point *);
+
 #ifdef CONFIG_NET
 extern int thermal_generate_netlink_event(u32 orig, enum events event);
 #else