[PATCH v3 4/4] thermal: show the sub thermal zones in sysfs

[Javi Merino]

When a thermal zone is created that has sub thermal zones via
devicetree or via thermal_zone_add_subtz() expose that relationship in
sysfs.

Cc: Zhang Rui <rui.zhang@xxxxxxxxx>
Cc: Eduardo Valentin <edubezval@xxxxxxxxx>
Signed-off-by: Javi Merino <javi.merino@xxxxxxx>
---
 Documentation/thermal/sysfs-api.txt |  33 ++++++++++
 drivers/thermal/thermal_core.c      | 125 ++++++++++++++++++++++++++++++++++++
 include/linux/thermal.h             |   3 +
 3 files changed, 161 insertions(+)

diff --git a/Documentation/thermal/sysfs-api.txt b/Documentation/thermal/sysfs-api.txt
index dda24a0bdeec..5636a531f0b1 100644
--- a/Documentation/thermal/sysfs-api.txt
+++ b/Documentation/thermal/sysfs-api.txt
@@ -219,11 +219,16 @@ Thermal zone device sys I/F, created once it's registered:
     |---temp:			Current temperature
     |---mode:			Working mode of the thermal zone
     |---policy:			Thermal governor used for this zone
+    |---aggregation_function:	Function to use when aggregating the
+				temperature of this zone's slave thermal zones
     |---available_policies:	Available thermal governors for this zone
     |---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
+    |---subtz[0-*]:		Slave thermal zones of this thermal zone
+    |---subtz[0-*]_weight:	Weight of the slave thermal zone on
+				this thermal zone
     |---sustainable_power:      Sustainable dissipatable power
     |---k_po:                   Proportional term during temperature overshoot
     |---k_pu:                   Proportional term during temperature undershoot
@@ -296,6 +301,19 @@ policy
 	One of the various thermal governors used for a particular zone.
 	RW, Required
 
+aggregation_function
+	The aggregation function used to calculate the temperature of
+	this thermal zone when it has sub thermal zones.  It can
+	either be "max" or "weighted_average".  If it's "max", the
+	temperature of this thermal zone is the maximum of the
+	temperatures of the sub thermal zones.  If
+	aggregation_function is "weighted_average", the temperature of
+	this thermal zone is the weighted average of the temperatures
+	of the sub thermal zones.  The weights are specified in
+	subtz[0-*]_weights.  The aggregation_function sysfs entry
+	doesn't exist for thermal zones without sub thermal zones.
+	RW, Optional
+
 available_policies
 	Available thermal governors which can be used for a particular zone.
 	RO, Required
@@ -359,6 +377,21 @@ emul_temp
 	  because userland can easily disable the thermal policy by simply
 	  flooding this sysfs node with low temperature values.
 
+subtz[0-*]
+	sysfs link to the slave thermal zone device.
+	RO, Optional
+
+subtz[0-*]_weight
+	The influence of subtz[0-*] in this thermal zone.  This
+	parameter is only used when using "weighted_average" as the
+	aggregation_function.  When calculating the temperature of
+	this thermal zone, the temperature of each of the thermal
+	zone's slaves is multiplied by its weight.  The result is
+	divided by the sum of all weights.  If all weights are 0,
+	the temperature of this thermal zone is the average of the
+	temperatures of the sub thermal zones.
+	RW, Optional
+
 sustainable_power
 	An estimate of the sustained power that can be dissipated by
 	the thermal zone. Used by the power allocator governor. For
diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
index 98bdb63b3b95..2bb1af0a9349 100644
--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c
@@ -63,14 +63,23 @@ static struct thermal_governor *def_governor;
 
 /**
  * struct thermal_zone_link - a link between "master" and "slave" thermal zones
+ * @id:		link number in the master thermal zone
+ * @name:	filename in the master thermal zone's sysfs directory
  * @weight:	weight of the @slave thermal zone in the master
  *		calculation.  Used when the master thermal zone's
  *		aggregation function is THERMAL_AGG_WEIGHTED_AVG
+ * @weight_attr_name:	filename of the weight attribute in the master's thermal
+ *			zone sysfs directory
+ * @weight_attr:	device attribute for the weight entry in sysfs
  * @slave:	pointer to the slave thermal zone
  * @node:	list node in the master thermal zone's slave_tzs list.
  */
 struct thermal_zone_link {
+	int id;
+	char name[THERMAL_NAME_LENGTH];
 	int weight;
+	char weight_attr_name[THERMAL_NAME_LENGTH];
+	struct device_attribute weight_attr;
 	struct thermal_zone_device *slave;
 	struct list_head node;
 };
@@ -990,6 +999,45 @@ emul_temp_store(struct device *dev, struct device_attribute *attr,
 static DEVICE_ATTR(emul_temp, S_IWUSR, NULL, emul_temp_store);
 
 static ssize_t
+agg_func_show(struct device *dev, struct device_attribute *devattr, char *buf)
+{
+	struct thermal_zone_device *tz = to_thermal_zone(dev);
+
+	if (tz->slave_agg_function == THERMAL_AGG_MAX)
+		return sprintf(buf, "max\n");
+	else if (tz->slave_agg_function == THERMAL_AGG_WEIGHTED_AVG)
+		return sprintf(buf, "weighted_average\n");
+	else
+		return sprintf(buf, "(invalid)\n");
+}
+
+static ssize_t
+agg_func_store(struct device *dev, struct device_attribute *attr,
+	       const char *buf, size_t count)
+{
+	int ret = 0;
+	struct thermal_zone_device *tz = to_thermal_zone(dev);
+	char func_name[THERMAL_NAME_LENGTH];
+
+	snprintf(func_name, sizeof(func_name), "%s", buf);
+
+	mutex_lock(&tz->lock);
+
+	if (sysfs_streq(func_name, "max"))
+		tz->slave_agg_function = THERMAL_AGG_MAX;
+	else if (sysfs_streq(func_name, "weighted_average"))
+		tz->slave_agg_function = THERMAL_AGG_WEIGHTED_AVG;
+	else
+		ret = -EINVAL;
+
+	mutex_unlock(&tz->lock);
+
+	return ret ? ret : count;
+}
+static DEVICE_ATTR(aggregation_function, S_IRUGO | S_IWUSR, agg_func_show,
+		   agg_func_store);
+
+static ssize_t
 sustainable_power_show(struct device *dev, struct device_attribute *devattr,
 		       char *buf)
 {
@@ -1305,6 +1353,35 @@ thermal_cooling_device_weight_store(struct device *dev,
 
 	return count;
 }
+
+static ssize_t
+thermal_subtz_weight_show(struct device *dev, struct device_attribute *attr,
+			  char *buf)
+{
+	struct thermal_zone_link *link;
+
+	link = container_of(attr, struct thermal_zone_link, weight_attr);
+
+	return sprintf(buf, "%d\n", link->weight);
+}
+
+static ssize_t
+thermal_subtz_weight_store(struct device *dev, struct device_attribute *attr,
+			   const char *buf, size_t count)
+{
+	struct thermal_zone_link *link;
+	int ret, weight;
+
+	ret = kstrtoint(buf, 0, &weight);
+	if (ret)
+		return ret;
+
+	link = container_of(attr, struct thermal_zone_link, weight_attr);
+	link->weight = weight;
+
+	return count;
+}
+
 /* Device management */
 
 /**
@@ -2135,6 +2212,47 @@ int thermal_zone_add_subtz(struct thermal_zone_device *tz,
 	link->weight = weight;
 	list_add_tail(&link->node, &tz->slave_tzs);
 
+	if (list_is_singular(&tz->slave_tzs)) {
+		ret = device_create_file(&tz->device,
+					 &dev_attr_aggregation_function);
+		if (ret)
+			pr_warn("Failed to create aggregation_function sysfs file: %d\n",
+				ret);
+			/*
+			 * Fall through: we failed to create the sysfs file, but
+			 * it's not fatal
+			 */
+	}
+
+	ret = get_idr(&tz->link_idr, NULL, &link->id);
+	if (ret) {
+		/*
+		 * Even if we can't create the symlink in sysfs,
+		 * we've linked the thermal zones, so return success
+		 */
+		ret = 0;
+		goto unlock;
+	}
+
+	snprintf(link->name, ARRAY_SIZE(link->name), "subtz%d", link->id);
+	ret = sysfs_create_link(&tz->device.kobj, &subtz->device.kobj,
+				link->name);
+	if (ret)
+		pr_warn("Failed to create symlink to sub thermal zone: %d\n",
+			ret);
+
+	snprintf(link->weight_attr_name, THERMAL_NAME_LENGTH, "subtz%d_weight",
+		 link->id);
+	sysfs_attr_init(&link->weight_attr.attr);
+	link->weight_attr.attr.name = link->weight_attr_name;
+	link->weight_attr.attr.mode = S_IWUSR | S_IRUGO;
+	link->weight_attr.show = thermal_subtz_weight_show;
+	link->weight_attr.store = thermal_subtz_weight_store;
+	ret = device_create_file(&tz->device, &link->weight_attr);
+	if (ret)
+		pr_warn("Failed to create sub thermal zone weight: %d\n",
+			ret);
+
 	ret = 0;
 
 unlock:
@@ -2166,6 +2284,10 @@ int thermal_zone_del_subtz(struct thermal_zone_device *tz,
 
 	list_for_each_entry(link, &tz->slave_tzs, node) {
 		if (link->slave == subtz) {
+			device_remove_file(&tz->device, &link->weight_attr);
+			sysfs_remove_link(&tz->device.kobj, link->name);
+			release_idr(&tz->link_idr, NULL, link->id);
+
 			list_del(&link->node);
 			kfree(link);
 
@@ -2174,6 +2296,9 @@ int thermal_zone_del_subtz(struct thermal_zone_device *tz,
 		}
 	}
 
+	if (list_empty(&tz->slave_tzs))
+		device_remove_file(&tz->device, &dev_attr_aggregation_function);
+
 	mutex_unlock(&tz->lock);
 
 	return ret;
diff --git a/include/linux/thermal.h b/include/linux/thermal.h
index dc3d2ab77ab6..f14884353230 100644
--- a/include/linux/thermal.h
+++ b/include/linux/thermal.h
@@ -192,6 +192,8 @@ struct thermal_attr {
  * @thermal_instances:	list of &struct thermal_instance of this thermal zone
  * @idr:	&struct idr to generate unique id for this zone's cooling
  *		devices
+ * @link_idr:	&struct idr to generate unique ids for this zone's links to
+ *		other thermal zones
  * @lock:	lock to protect thermal_instances list
  * @node:	node in thermal_tz_list (in thermal_core.c)
  * @poll_queue:	delayed work for polling
@@ -221,6 +223,7 @@ struct thermal_zone_device {
 	void *governor_data;
 	struct list_head thermal_instances;
 	struct idr idr;
+	struct idr link_idr;
 	struct mutex lock;
 	struct list_head node;
 	struct delayed_work poll_queue;
-- 
1.9.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/