-----Original Message-----
From: Hongbo Zhang [mailto:hongbo.zhang@linaro.org]
Sent: Monday, December 03, 2012 1:51 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 2/7] Thermal: Create zone level APIs

On 3 December 2012 15:47, R, Durgadoss [off-list ref] wrote:

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-----Original Message-----
From: Hongbo Zhang [mailto:hongbo.zhang@linaro.org]
Sent: Monday, December 03, 2012 1:13 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 2/7] Thermal: Create zone level APIs

On 17 November 2012 18:45, Durgadoss R [off-list ref]

wrote:

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This patch adds a new thermal_zone structure to
thermal.h. Also, adds zone level APIs to the thermal
framework.

Signed-off-by: Durgadoss R <redacted>
---
 drivers/thermal/thermal_sys.c |  206

+++++++++++++++++++++++++++++++++++++++++

quoted

 include/linux/thermal.h       |   25 +++++
 2 files changed, 231 insertions(+)

diff --git a/drivers/thermal/thermal_sys.c

b/drivers/thermal/thermal_sys.c

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index e726c8b..9d386d7 100644

--- a/drivers/thermal/thermal_sys.c
+++ b/drivers/thermal/thermal_sys.c

@@ -44,19 +44,28 @@ MODULE_DESCRIPTION("Generic thermal

management sysfs support");

quoted

 MODULE_LICENSE("GPL");

 static DEFINE_IDR(thermal_tz_idr);
+static DEFINE_IDR(thermal_zone_idr);
 static DEFINE_IDR(thermal_cdev_idr);
 static DEFINE_IDR(thermal_sensor_idr);
 static DEFINE_MUTEX(thermal_idr_lock);

 static LIST_HEAD(thermal_tz_list);
 static LIST_HEAD(thermal_sensor_list);
+static LIST_HEAD(thermal_zone_list);
 static LIST_HEAD(thermal_cdev_list);
 static LIST_HEAD(thermal_governor_list);

 static DEFINE_MUTEX(thermal_list_lock);
 static DEFINE_MUTEX(ts_list_lock);
+static DEFINE_MUTEX(tz_list_lock);
 static DEFINE_MUTEX(thermal_governor_lock);

+#define for_each_thermal_sensor(pos) \
+       list_for_each_entry(pos, &thermal_sensor_list, node)
+
+#define for_each_thermal_zone(pos) \
+       list_for_each_entry(pos, &thermal_zone_list, node)
+
 static struct thermal_governor *__find_governor(const char *name)
 {
        struct thermal_governor *pos;

@@ -419,15 +428,62 @@ static void thermal_zone_device_check(struct

work_struct *work)

quoted

        thermal_zone_device_update(tz);
 }

+static int get_sensor_indx(struct thermal_zone *tz, struct

thermal_sensor

quoted

quoted

*ts)

quoted

+{
+       int i, indx = -EINVAL;
+
+       if (!tz || !ts)
+               return -EINVAL;
+
+       mutex_lock(&ts_list_lock);
+       for (i = 0; i < tz->sensor_indx; i++) {
+               if (tz->sensors[i] == ts) {
+                       indx = i;
+                       break;
+               }
+       }
+       mutex_unlock(&ts_list_lock);
+       return indx;
+}
+
+static void remove_sensor_from_zone(struct thermal_zone *tz,
+                               struct thermal_sensor *ts)
+{
+       int indx, j;
+
+       indx = get_sensor_indx(tz, ts);
+       if (indx < 0)
+               return;
+
+       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++)
+               tz->sensors[j] = tz->sensors[j + 1];
+
+       tz->sensor_indx--;
+}
+
 /* sys I/F for thermal zone */

 #define to_thermal_zone(_dev) \
        container_of(_dev, struct thermal_zone_device, device)

+#define to_zone(_dev) \
+       container_of(_dev, struct thermal_zone, device)
+
 #define to_thermal_sensor(_dev) \
        container_of(_dev, struct thermal_sensor, device)

 static ssize_t
+zone_name_show(struct device *dev, struct device_attribute *attr,

char

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*buf)

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+{
+       struct thermal_zone *tz = to_zone(dev);
+
+       return sprintf(buf, "%s\n", tz->name);
+}
+
+static ssize_t
 sensor_name_show(struct device *dev, struct device_attribute *attr,

char

quoted

quoted

*buf)

quoted

 {
        struct thermal_sensor *ts = to_thermal_sensor(dev);

@@ -772,6 +828,8 @@ static DEVICE_ATTR(policy, S_IRUGO | S_IWUSR,

policy_show, policy_store);

quoted

 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);
+
 /* sys I/F for cooling device */
 #define to_cooling_device(_dev)        \
        container_of(_dev, struct thermal_cooling_device, device)

@@ -1557,6 +1615,146 @@ static void remove_trip_attrs(struct

thermal_zone_device *tz)

quoted

        kfree(tz->trip_hyst_attrs);
 }

+struct thermal_zone *create_thermal_zone(const char *name, void

*devdata)

quoted

+{
+       struct thermal_zone *tz;
+       int ret;
+
+       if (!name || (name && strlen(name) >=

THERMAL_NAME_LENGTH))

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quoted

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+               return ERR_PTR(-EINVAL);
+
+       tz = kzalloc(sizeof(*tz), GFP_KERNEL);
+       if (!tz)
+               return ERR_PTR(-ENOMEM);
+
+       idr_init(&tz->idr);
+       ret = get_idr(&thermal_zone_idr, &thermal_idr_lock, &tz->id);
+       if (ret)
+               goto exit_free;
+
+       strcpy(tz->name, name);
+       tz->devdata = devdata;
+       tz->device.class = &thermal_class;
+
+       dev_set_name(&tz->device, "zone%d", tz->id);
+       ret = device_register(&tz->device);
+       if (ret)
+               goto exit_idr;
+
+       ret = device_create_file(&tz->device, &dev_attr_zone_name);
+       if (ret)
+               goto exit_unregister;
+
+       /* 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_unregister:
+       device_unregister(&tz->device);
+exit_idr:
+       release_idr(&thermal_zone_idr, &thermal_idr_lock, tz->id);
+exit_free:
+       kfree(tz);
+       return ERR_PTR(ret);
+}
+EXPORT_SYMBOL(create_thermal_zone);
+
+void remove_thermal_zone(struct thermal_zone *tz)
+{
+       struct thermal_zone *pos, *next;
+       bool found = false;
+
+       if (!tz)
+               return;
+
+       mutex_lock(&tz_list_lock);
+
+       list_for_each_entry_safe(pos, next, &thermal_zone_list, node) {
+               if (pos == tz) {
+                       list_del(&tz->node);
+                       found = true;
+                       break;
+               }
+       }
+
+       if (!found)
+               goto exit;
+
+       device_remove_file(&tz->device, &dev_attr_zone_name);
+
+       release_idr(&thermal_zone_idr, &thermal_idr_lock, tz->id);
+       idr_destroy(&tz->idr);
+
+       device_unregister(&tz->device);
+       kfree(tz);
+exit:
+       mutex_unlock(&tz_list_lock);
+       return;
+}
+EXPORT_SYMBOL(remove_thermal_zone);
+
+struct thermal_sensor *get_sensor_by_name(const char *name)
+{
+       struct thermal_sensor *pos;
+       struct thermal_sensor *ts = NULL;
+
+       mutex_lock(&ts_list_lock);
+       for_each_thermal_sensor(pos) {
+               if (!strnicmp(pos->name, name, THERMAL_NAME_LENGTH)) {
+                       ts = pos;
+                       break;
+               }
+       }
+       mutex_unlock(&ts_list_lock);
+       return ts;
+}
+EXPORT_SYMBOL(get_sensor_by_name);
+
+int add_sensor_to_zone_by_name(struct thermal_zone *tz, const

char

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*name)

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+{
+       int ret;
+       struct thermal_sensor *ts = get_sensor_by_name(name);
+
+       if (!tz || !ts)
+               return -EINVAL;
+
+       mutex_lock(&tz_list_lock);
+
+       /* Ensure we are not adding the same sensor again!! */
+       ret = get_sensor_indx(tz, ts);
+       if (ret >= 0) {
+               ret = -EEXIST;
+               goto exit_zone;
+       }
+
+       mutex_lock(&ts_list_lock);
+
+       ret = sysfs_create_link(&tz->device.kobj, &ts->device.kobj,
+                               kobject_name(&ts->device.kobj));
+       if (ret)
+               goto exit_sensor;
+
+       tz->sensors[tz->sensor_indx++] = ts;
+
+exit_sensor:
+       mutex_unlock(&ts_list_lock);
+exit_zone:
+       mutex_unlock(&tz_list_lock);
+       return ret;
+}
+EXPORT_SYMBOL(add_sensor_to_zone_by_name);
+
+int add_sensor_to_zone(struct thermal_zone *tz, struct

thermal_sensor

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*ts)

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+{
+       if (!tz || !ts)
+               return -EINVAL;
+
+       return add_sensor_to_zone_by_name(tz, ts->name);
+}
+EXPORT_SYMBOL(add_sensor_to_zone);
+
 /**
  * thermal_sensor_register - register a new thermal sensor
  * @name:      name of the thermal sensor

@@ -1624,6 +1822,7 @@ EXPORT_SYMBOL(thermal_sensor_register);
 void thermal_sensor_unregister(struct thermal_sensor *ts)
 {
        int i;
+       struct thermal_zone *tz;
        struct thermal_sensor *pos, *next;
        bool found = false;

@@ -1643,6 +1842,13 @@ void thermal_sensor_unregister(struct

thermal_sensor *ts)

quoted

        if (!found)
                return;

+       mutex_lock(&tz_list_lock);
+
+       for_each_thermal_zone(tz)
+               remove_sensor_from_zone(tz, ts);
+
+       mutex_unlock(&tz_list_lock);
+
        for (i = 0; i < ts->thresholds; i++)
                device_remove_file(&ts->device, &ts->thresh_attrs[i].attr);

diff --git a/include/linux/thermal.h b/include/linux/thermal.h
index e2f85ec..38438be 100644
--- a/include/linux/thermal.h
+++ b/include/linux/thermal.h

@@ -49,6 +49,11 @@
 /* Default Thermal Governor: Does Linear Throttling */
 #define DEFAULT_THERMAL_GOVERNOR       "step_wise"

+/* Maximum number of sensors, allowed in a thermal zone
+ * We will start with 5, and increase if needed.
+ */
+#define MAX_SENSORS_PER_ZONE           5
+
 struct thermal_sensor;
 struct thermal_zone_device;
 struct thermal_cooling_device;

@@ -191,6 +196,21 @@ struct thermal_zone_device {
        struct delayed_work poll_queue;
 };

+struct thermal_zone {
+       char name[THERMAL_NAME_LENGTH];
+       int id;
+       void *devdata;
+       struct thermal_zone *ops;

What is this, thermal_zone_device_ops? and how to initialize this ops?

oh, Not required, for now. Will remove it..
Good catch :-)

I am still confused a bit.
Is this thermal_zone going to take the place of the old
thermal_zone_device?

Yes, it will replace the older one.

If yes, which functions/callbacks are used to access
thermal_zone->trip[] like the old get_trip_*?

We will not have call backs associated with 'zone'.
A zone is kind of a virtual entity, which can have one or
more sensors associated with it.

Trip points are attached to 'a sensor' which can be in
any zone. So, thermal_sensor_ops functions will help you
access the trip values.

Thanks,
Durga

quoted

Thanks,
Durga

quoted

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+       struct thermal_governor *governor;
+       struct idr idr;
+       struct device device;
+       struct list_head node;
+
+       /* Sensor level information */
+       int sensor_indx; /* index into 'sensors' array */
+       struct thermal_sensor *sensors[MAX_SENSORS_PER_ZONE];
+};
+
 /* Structure that holds thermal governor information */
 struct thermal_governor {
        char name[THERMAL_NAME_LENGTH];

@@ -264,6 +284,11 @@ struct thermal_sensor

*thermal_sensor_register(const char *,

quoted

 void thermal_sensor_unregister(struct thermal_sensor *);
 int enable_sensor_thresholds(struct thermal_sensor *, int);

+struct thermal_zone *create_thermal_zone(const char *, void *);
+void remove_thermal_zone(struct thermal_zone *);
+int add_sensor_to_zone(struct thermal_zone *, struct thermal_sensor

*);

quoted

+int add_sensor_to_zone_by_name(struct thermal_zone *, const char

*);

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+
 #ifdef CONFIG_NET
 extern int thermal_generate_netlink_event(u32 orig, enum events

event);

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 #else
--
1.7.9.5