the generic thermal sysfs driver

The Generic Thermal sysfs driver for thermal management.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Thomas Sujith <sujith.thomas@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

7 files changed, 1073 insertions, 0 deletions

diff --git a/Documentation/thermal/sysfs-api.txt b/Documentation/thermal/sysfs-api.txt
new file mode 100644
index 000000000000..5776e090359d
--- /dev/null
+++ b/Documentation/thermal/sysfs-api.txt
@@ -0,0 +1,246 @@
+Generic Thermal Sysfs driver How To
+=========================
+
+Written by Sujith Thomas <sujith.thomas@intel.com>, Zhang Rui <rui.zhang@intel.com>
+
+Updated: 2 January 2008
+
+Copyright (c)  2008 Intel Corporation
+
+
+0. Introduction
+
+The generic thermal sysfs provides a set of interfaces for thermal zone devices (sensors)
+and thermal cooling devices (fan, processor...) to register with the thermal management
+solution and to be a part of it.
+
+This how-to focusses on enabling new thermal zone and cooling devices to participate
+in thermal management.
+This solution is platform independent and any type of thermal zone devices and
+cooling devices should be able to make use of the infrastructure.
+
+The main task of the thermal sysfs driver is to expose thermal zone attributes as well
+as cooling device attributes to the user space.
+An intelligent thermal management application can make decisions based on inputs
+from thermal zone attributes (the current temperature and trip point temperature)
+and throttle appropriate devices.
+
+[0-*]   denotes any positive number starting from 0
+[1-*]   denotes any positive number starting from 1
+
+1. thermal sysfs driver interface functions
+
+1.1 thermal zone device interface
+1.1.1 struct thermal_zone_device *thermal_zone_device_register(char *name, int trips,
+                                void *devdata, struct thermal_zone_device_ops *ops)
+
+        This interface function adds a new thermal zone device (sensor) to
+        /sys/class/thermal folder as thermal_zone[0-*].
+        It tries to bind all the thermal cooling devices registered at the same time.
+
+        name: the thermal zone name.
+        trips: the total number of trip points this thermal zone supports.
+        devdata: device private data
+        ops: thermal zone device callbacks.
+                .bind: bind the thermal zone device with a thermal cooling device.
+                .unbind: unbing the thermal zone device with a thermal cooling device.
+                .get_temp: get the current temperature of the thermal zone.
+                .get_mode: get the current mode (user/kernel) of the thermal zone.
+                           "kernel" means thermal management is done in kernel.
+                           "user" will prevent kernel thermal driver actions upon trip points
+                           so that user applications can take charge of thermal management.
+                .set_mode: set the mode (user/kernel) of the thermal zone.
+                .get_trip_type: get the type of certain trip point.
+                .get_trip_temp: get the temperature above which the certain trip point
+                                will be fired.
+
+1.1.2 void thermal_zone_device_unregister(struct thermal_zone_device *tz)
+
+        This interface function removes the thermal zone device.
+        It deletes the corresponding entry form /sys/class/thermal folder and unbind all
+        the thermal cooling devices it uses.
+
+1.2 thermal cooling device interface
+1.2.1 struct thermal_cooling_device *thermal_cooling_device_register(char *name,
+                                        void *devdata, struct thermal_cooling_device_ops *)
+
+        This interface function adds a new thermal cooling device (fan/processor/...) to
+        /sys/class/thermal/ folder as cooling_device[0-*].
+        It tries to bind itself to all the thermal zone devices register at the same time.
+        name: the cooling device name.
+        devdata: device private data.
+        ops: thermal cooling devices callbacks.
+                .get_max_state: get the Maximum throttle state of the cooling device.
+                .get_cur_state: get the Current throttle state of the cooling device.
+                .set_cur_state: set the Current throttle state of the cooling device.
+
+1.2.2 void thermal_cooling_device_unregister(struct thermal_cooling_device *cdev)
+
+        This interface function remove the thermal cooling device.
+        It deletes the corresponding entry form /sys/class/thermal folder and unbind
+        itself from all the thermal zone devices using it.
+
+1.3 interface for binding a thermal zone device with a thermal cooling device
+1.3.1 int thermal_zone_bind_cooling_device(struct thermal_zone_device *tz,
+                        int trip, struct thermal_cooling_device *cdev);
+
+        This interface function bind a thermal cooling device to the certain trip point
+        of a thermal zone device.
+        This function is usually called in the thermal zone device .bind callback.
+        tz: the thermal zone device
+        cdev: thermal cooling device
+        trip: indicates which trip point the cooling devices is associated with
+                 in this thermal zone.
+
+1.3.2 int thermal_zone_unbind_cooling_device(struct thermal_zone_device *tz,
+                                int trip, struct thermal_cooling_device *cdev);
+
+        This interface function unbind a thermal cooling device from the certain trip point
+        of a thermal zone device.
+        This function is usually called in the thermal zone device .unbind callback.
+        tz: the thermal zone device
+        cdev: thermal cooling device
+        trip: indicates which trip point the cooling devices is associated with
+                in this thermal zone.
+
+2. sysfs attributes structure
+
+RO      read only value
+RW      read/write value
+
+All thermal sysfs attributes will be represented under /sys/class/thermal
+/sys/class/thermal/
+
+Thermal zone device sys I/F, created once it's registered:
+|thermal_zone[0-*]:
+        |-----type:                     Type of the thermal zone
+        |-----temp:                     Current temperature
+        |-----mode:                     Working mode of the thermal zone
+        |-----trip_point_[0-*]_temp:    Trip point temperature
+        |-----trip_point_[0-*]_type:    Trip point type
+
+Thermal cooling device sys I/F, created once it's registered:
+|cooling_device[0-*]:
+        |-----type :                    Type of the cooling device(processor/fan/...)
+        |-----max_state:                Maximum cooling state of the cooling device
+        |-----cur_state:                Current cooling state of the cooling device
+
+
+These two dynamic attributes are created/removed in pairs.
+They represent the relationship between a thermal zone and its associated cooling device.
+They are created/removed for each
+thermal_zone_bind_cooling_device/thermal_zone_unbind_cooling_device successful exection.
+
+|thermal_zone[0-*]
+        |-----cdev[0-*]:                The [0-*]th cooling device in the current thermal zone
+        |-----cdev[0-*]_trip_point:     Trip point that cdev[0-*] is associated with
+
+
+***************************
+* Thermal zone attributes *
+***************************
+
+type                            Strings which represent the thermal zone type.
+                                This is given by thermal zone driver as part of registration.
+                                Eg: "ACPI thermal zone" indicates it's a ACPI thermal device
+                                RO
+                                Optional
+
+temp                            Current temperature as reported by thermal zone (sensor)
+                                Unit: degree celsius
+                                RO
+                                Required
+
+mode                            One of the predifned values in [kernel, user]
+                                This file gives information about the algorithm
+                                that is currently managing the thermal zone.
+                                It can be either default kernel based algorithm
+                                or user space application.
+                                RW
+                                Optional
+                                kernel  = Thermal management in kernel thermal zone driver.
+                                user    = Preventing kernel thermal zone driver actions upon
+                                          trip points so that user application can take full
+                                          charge of the thermal management.
+
+trip_point_[0-*]_temp           The temperature above which trip point will be fired
+                                Unit: degree celsius
+                                RO
+                                Optional
+
+trip_point_[0-*]_type           Strings which indicate the type of the trip point
+                                Eg. it can be one of critical, hot, passive,
+                                    active[0-*] for ACPI thermal zone.
+                                RO
+                                Optional
+
+cdev[0-*]                       Sysfs link to the thermal cooling device node where the sys I/F
+                                for cooling device throttling control represents.
+                                RO
+                                Optional
+
+cdev[0-*]_trip_point            The trip point with which cdev[0-*] is assocated in this thermal zone
+                                -1 means the cooling device is not associated with any trip point.
+                                RO
+                                Optional
+
+******************************
+* Cooling device  attributes *
+******************************
+
+type                            String which represents the type of device
+                                eg: For generic ACPI: this should be "Fan",
+                                "Processor" or "LCD"
+                                eg. For memory controller device on intel_menlow platform:
+                                this should be "Memory controller"
+                                RO
+                                Optional
+
+max_state                       The maximum permissible cooling state of this cooling device.
+                                RO
+                                Required
+
+cur_state                       The current cooling state of this cooling device.
+                                the value can any integer numbers between 0 and max_state,
+                                cur_state == 0 means no cooling
+                                cur_state == max_state means the maximum cooling.
+                                RW
+                                Required
+
+3. A simple implementation
+
+ACPI thermal zone may support multiple trip points like critical/hot/passive/active.
+If an ACPI thermal zone supports critical, passive, active[0] and active[1] at the same time,
+it may register itself as a thermale_zone_device (thermal_zone1) with 4 trip points in all.
+It has one processor and one fan, which are both registered as thermal_cooling_device.
+If the processor is listed in _PSL method, and the fan is listed in _AL0 method,
+the sys I/F structure will be built like this:
+
+/sys/class/thermal:
+
+|thermal_zone1:
+        |-----type:                     ACPI thermal zone
+        |-----temp:                     37
+        |-----mode:                     kernel
+        |-----trip_point_0_temp:        100
+        |-----trip_point_0_type:        critical
+        |-----trip_point_1_temp:        80
+        |-----trip_point_1_type:        passive
+        |-----trip_point_2_temp:        70
+        |-----trip_point_2_type:        active[0]
+        |-----trip_point_3_temp:        60
+        |-----trip_point_3_type:        active[1]
+        |-----cdev0:                    --->/sys/class/thermal/cooling_device0
+        |-----cdev0_trip_point:         1       /* cdev0 can be used for passive */
+        |-----cdev1:                    --->/sys/class/thermal/cooling_device3
+        |-----cdev1_trip_point:         2       /* cdev1 can be used for active[0]*/
+
+|cooling_device0:
+        |-----type:                     Processor
+        |-----max_state:                8
+        |-----cur_state:                0
+
+|cooling_device3:
+        |-----type:                     Fan
+        |-----max_state:                2
+        |-----cur_state:                0
diff --git a/drivers/Kconfig b/drivers/Kconfig
index 08d4ae201597..8e238cfc0795 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -58,6 +58,8 @@ source "drivers/power/Kconfig"
 
 source "drivers/hwmon/Kconfig"
 
+source "drivers/thermal/Kconfig"
+
 source "drivers/watchdog/Kconfig"
 
 source "drivers/ssb/Kconfig"
diff --git a/drivers/Makefile b/drivers/Makefile
index 0ee9a8a4095e..a516b8b19127 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -64,6 +64,7 @@ obj-y				+= i2c/
 obj-$(CONFIG_W1)                += w1/
 obj-$(CONFIG_POWER_SUPPLY)      += power/
 obj-$(CONFIG_HWMON)             += hwmon/
+obj-$(CONFIG_THERMAL)           += thermal/
 obj-$(CONFIG_WATCHDOG)          += watchdog/
 obj-$(CONFIG_PHONE)             += telephony/
 obj-$(CONFIG_MD)                += md/
diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
new file mode 100644
index 000000000000..9b3f61200000
--- /dev/null
+++ b/drivers/thermal/Kconfig
@@ -0,0 +1,15 @@
+#
+# Generic thermal sysfs drivers configuration
+#
+
+menuconfig THERMAL
+        bool "Generic Thermal sysfs driver"
+        default y
+        help
+          Generic Thermal Sysfs driver offers a generic mechanism for
+          thermal management. Usually it's made up of one or more thermal
+          zone and cooling device.
+          each thermal zone contains its own temperature, trip points,
+          cooling devices.
+          All platforms with ACPI thermal support can use this driver.
+          If you want this support, you should say Y here
diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
new file mode 100644
index 000000000000..8ef1232de376
--- /dev/null
+++ b/drivers/thermal/Makefile
@@ -0,0 +1,5 @@
+#
+# Makefile for sensor chip drivers.
+#
+
+obj-$(CONFIG_THERMAL)           += thermal.o
diff --git a/drivers/thermal/thermal.c b/drivers/thermal/thermal.c
new file mode 100644
index 000000000000..3273e348fd14
--- /dev/null
+++ b/drivers/thermal/thermal.c
@@ -0,0 +1,714 @@
+/*
+ *  thermal.c - Generic Thermal Management Sysfs support.
+ *
+ *  Copyright (C) 2008 Intel Corp
+ *  Copyright (C) 2008 Zhang Rui <rui.zhang@intel.com>
+ *  Copyright (C) 2008 Sujith Thomas <sujith.thomas@intel.com>
+ *
+ *  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; version 2 of the License.
+ *
+ *  This program is distributed in the hope that it will be useful, but
+ *  WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, write to the Free Software Foundation, Inc.,
+ *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ */
+
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/kdev_t.h>
+#include <linux/idr.h>
+#include <linux/thermal.h>
+#include <linux/spinlock.h>
+
+MODULE_AUTHOR("Zhang Rui")
+MODULE_DESCRIPTION("Generic thermal management sysfs support");
+MODULE_LICENSE("GPL");
+
+#define PREFIX "Thermal: "
+
+struct thermal_cooling_device_instance {
+        int id;
+        char name[THERMAL_NAME_LENGTH];
+        struct thermal_zone_device *tz;
+        struct thermal_cooling_device *cdev;
+        int trip;
+        char attr_name[THERMAL_NAME_LENGTH];
+        struct device_attribute attr;
+        struct list_head node;
+};
+
+static DEFINE_IDR(thermal_tz_idr);
+static DEFINE_IDR(thermal_cdev_idr);
+static DEFINE_MUTEX(thermal_idr_lock);
+
+static LIST_HEAD(thermal_tz_list);
+static LIST_HEAD(thermal_cdev_list);
+static DEFINE_MUTEX(thermal_list_lock);
+
+static int get_idr(struct idr *idr, struct mutex *lock, int *id)
+{
+        int err;
+
+      again:
+        if (unlikely(idr_pre_get(idr, GFP_KERNEL) == 0))
+                return -ENOMEM;
+
+        if (lock)
+                mutex_lock(lock);
+        err = idr_get_new(idr, NULL, id);
+        if (lock)
+                mutex_unlock(lock);
+        if (unlikely(err == -EAGAIN))
+                goto again;
+        else if (unlikely(err))
+                return err;
+
+        *id = *id & MAX_ID_MASK;
+        return 0;
+}
+
+static void release_idr(struct idr *idr, struct mutex *lock, int id)
+{
+        if (lock)
+                mutex_lock(lock);
+        idr_remove(idr, id);
+        if (lock)
+                mutex_unlock(lock);
+}
+
+/* sys I/F for thermal zone */
+
+#define to_thermal_zone(_dev) \
+        container_of(_dev, struct thermal_zone_device, device)
+
+static ssize_t
+type_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+        struct thermal_zone_device *tz = to_thermal_zone(dev);
+
+        return sprintf(buf, "%s\n", tz->type);
+}
+
+static ssize_t
+temp_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+        struct thermal_zone_device *tz = to_thermal_zone(dev);
+
+        if (!tz->ops->get_temp)
+                return -EPERM;
+
+        return tz->ops->get_temp(tz, buf);
+}
+
+static ssize_t
+mode_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+        struct thermal_zone_device *tz = to_thermal_zone(dev);
+
+        if (!tz->ops->get_mode)
+                return -EPERM;
+
+        return tz->ops->get_mode(tz, buf);
+}
+
+static ssize_t
+mode_store(struct device *dev, struct device_attribute *attr,
+           const char *buf, size_t count)
+{
+        struct thermal_zone_device *tz = to_thermal_zone(dev);
+        int result;
+
+        if (!tz->ops->set_mode)
+                return -EPERM;
+
+        result = tz->ops->set_mode(tz, buf);
+        if (result)
+                return result;
+
+        return count;
+}
+
+static ssize_t
+trip_point_type_show(struct device *dev, struct device_attribute *attr,
+                     char *buf)
+{
+        struct thermal_zone_device *tz = to_thermal_zone(dev);
+        int trip;
+
+        if (!tz->ops->get_trip_type)
+                return -EPERM;
+
+        if (!sscanf(attr->attr.name, "trip_point_%d_type", &trip))
+                return -EINVAL;
+
+        return tz->ops->get_trip_type(tz, trip, buf);
+}
+
+static ssize_t
+trip_point_temp_show(struct device *dev, struct device_attribute *attr,
+                     char *buf)
+{
+        struct thermal_zone_device *tz = to_thermal_zone(dev);
+        int trip;
+
+        if (!tz->ops->get_trip_temp)
+                return -EPERM;
+
+        if (!sscanf(attr->attr.name, "trip_point_%d_temp", &trip))
+                return -EINVAL;
+
+        return tz->ops->get_trip_temp(tz, trip, buf);
+}
+
+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);
+
+static struct device_attribute trip_point_attrs[] = {
+        __ATTR(trip_point_0_type, 0444, trip_point_type_show, NULL),
+        __ATTR(trip_point_0_temp, 0444, trip_point_temp_show, NULL),
+        __ATTR(trip_point_1_type, 0444, trip_point_type_show, NULL),
+        __ATTR(trip_point_1_temp, 0444, trip_point_temp_show, NULL),
+        __ATTR(trip_point_2_type, 0444, trip_point_type_show, NULL),
+        __ATTR(trip_point_2_temp, 0444, trip_point_temp_show, NULL),
+        __ATTR(trip_point_3_type, 0444, trip_point_type_show, NULL),
+        __ATTR(trip_point_3_temp, 0444, trip_point_temp_show, NULL),
+        __ATTR(trip_point_4_type, 0444, trip_point_type_show, NULL),
+        __ATTR(trip_point_4_temp, 0444, trip_point_temp_show, NULL),
+        __ATTR(trip_point_5_type, 0444, trip_point_type_show, NULL),
+        __ATTR(trip_point_5_temp, 0444, trip_point_temp_show, NULL),
+        __ATTR(trip_point_6_type, 0444, trip_point_type_show, NULL),
+        __ATTR(trip_point_6_temp, 0444, trip_point_temp_show, NULL),
+        __ATTR(trip_point_7_type, 0444, trip_point_type_show, NULL),
+        __ATTR(trip_point_7_temp, 0444, trip_point_temp_show, NULL),
+        __ATTR(trip_point_8_type, 0444, trip_point_type_show, NULL),
+        __ATTR(trip_point_8_temp, 0444, trip_point_temp_show, NULL),
+        __ATTR(trip_point_9_type, 0444, trip_point_type_show, NULL),
+        __ATTR(trip_point_9_temp, 0444, trip_point_temp_show, NULL),
+};
+
+#define TRIP_POINT_ATTR_ADD(_dev, _index, result)     \
+do {    \
+        result = device_create_file(_dev,       \
+                                &trip_point_attrs[_index * 2]); \
+        if (result)     \
+                break;  \
+        result = device_create_file(_dev,       \
+                        &trip_point_attrs[_index * 2 + 1]);     \
+} while (0)
+
+#define TRIP_POINT_ATTR_REMOVE(_dev, _index)    \
+do {    \
+        device_remove_file(_dev, &trip_point_attrs[_index * 2]);        \
+        device_remove_file(_dev, &trip_point_attrs[_index * 2 + 1]);    \
+} while (0)
+
+/* sys I/F for cooling device */
+#define to_cooling_device(_dev) \
+        container_of(_dev, struct thermal_cooling_device, device)
+
+static ssize_t
+thermal_cooling_device_type_show(struct device *dev,
+                                 struct device_attribute *attr, char *buf)
+{
+        struct thermal_cooling_device *cdev = to_cooling_device(dev);
+
+        return sprintf(buf, "%s\n", cdev->type);
+}
+
+static ssize_t
+thermal_cooling_device_max_state_show(struct device *dev,
+                                      struct device_attribute *attr, char *buf)
+{
+        struct thermal_cooling_device *cdev = to_cooling_device(dev);
+
+        return cdev->ops->get_max_state(cdev, buf);
+}
+
+static ssize_t
+thermal_cooling_device_cur_state_show(struct device *dev,
+                                      struct device_attribute *attr, char *buf)
+{
+        struct thermal_cooling_device *cdev = to_cooling_device(dev);
+
+        return cdev->ops->get_cur_state(cdev, buf);
+}
+
+static ssize_t
+thermal_cooling_device_cur_state_store(struct device *dev,
+                                       struct device_attribute *attr,
+                                       const char *buf, size_t count)
+{
+        struct thermal_cooling_device *cdev = to_cooling_device(dev);
+        int state;
+        int result;
+
+        if (!sscanf(buf, "%d\n", &state))
+                return -EINVAL;
+
+        if (state < 0)
+                return -EINVAL;
+
+        result = cdev->ops->set_cur_state(cdev, state);
+        if (result)
+                return result;
+        return count;
+}
+
+static struct device_attribute dev_attr_cdev_type =
+                __ATTR(type, 0444, thermal_cooling_device_type_show, NULL);
+static DEVICE_ATTR(max_state, 0444,
+                   thermal_cooling_device_max_state_show, NULL);
+static DEVICE_ATTR(cur_state, 0644,
+                   thermal_cooling_device_cur_state_show,
+                   thermal_cooling_device_cur_state_store);
+
+static ssize_t
+thermal_cooling_device_trip_point_show(struct device *dev,
+                                    struct device_attribute *attr, char *buf)
+{
+        struct thermal_cooling_device_instance *instance;
+
+        instance =
+            container_of(attr, struct thermal_cooling_device_instance, attr);
+
+        if (instance->trip == THERMAL_TRIPS_NONE)
+                return sprintf(buf, "-1\n");
+        else
+                return sprintf(buf, "%d\n", instance->trip);
+}
+
+/* Device management */
+
+/**
+ * thermal_zone_bind_cooling_device - bind a cooling device to a thermal zone
+ * this function is usually called in the thermal zone device .bind callback.
+ * @tz:         thermal zone device
+ * @trip:       indicates which trip point the cooling devices is
+ *              associated with in this thermal zone.
+ * @cdev:       thermal cooling device
+ */
+int thermal_zone_bind_cooling_device(struct thermal_zone_device *tz,
+                                     int trip,
+                                     struct thermal_cooling_device *cdev)
+{
+        struct thermal_cooling_device_instance *dev;
+        struct thermal_cooling_device_instance *pos;
+        int result;
+
+        if (trip >= tz->trips ||
+            (trip < 0 && trip != THERMAL_TRIPS_NONE))
+                return -EINVAL;
+
+        if (!tz || !cdev)
+                return -EINVAL;
+
+        dev =
+            kzalloc(sizeof(struct thermal_cooling_device_instance), GFP_KERNEL);
+        if (!dev)
+                return -ENOMEM;
+        dev->tz = tz;
+        dev->cdev = cdev;
+        dev->trip = trip;
+        result = get_idr(&tz->idr, &tz->lock, &dev->id);
+        if (result)
+                goto free_mem;
+
+        sprintf(dev->name, "cdev%d", dev->id);
+        result =
+            sysfs_create_link(&tz->device.kobj, &cdev->device.kobj, dev->name);
+        if (result)
+                goto release_idr;
+
+        sprintf(dev->attr_name, "cdev%d_trip_point", dev->id);
+        dev->attr.attr.name = dev->attr_name;
+        dev->attr.attr.mode = 0444;
+        dev->attr.show = thermal_cooling_device_trip_point_show;
+        result = device_create_file(&tz->device, &dev->attr);
+        if (result)
+                goto remove_symbol_link;
+
+        mutex_lock(&tz->lock);
+        list_for_each_entry(pos, &tz->cooling_devices, node)
+            if (pos->tz == tz && pos->trip == trip && pos->cdev == cdev) {
+                result = -EEXIST;
+                break;
+        }
+        if (!result)
+                list_add_tail(&dev->node, &tz->cooling_devices);
+        mutex_unlock(&tz->lock);
+
+        if (!result)
+                return 0;
+
+        device_remove_file(&tz->device, &dev->attr);
+      remove_symbol_link:
+        sysfs_remove_link(&tz->device.kobj, dev->name);
+      release_idr:
+        release_idr(&tz->idr, &tz->lock, dev->id);
+      free_mem:
+        kfree(dev);
+        return result;
+}
+EXPORT_SYMBOL(thermal_zone_bind_cooling_device);
+
+/**
+ * thermal_zone_unbind_cooling_device - unbind a cooling device from a thermal zone
+ * this function is usually called in the thermal zone device .unbind callback.
+ * @tz:         thermal zone device
+ * @trip:       indicates which trip point the cooling devices is
+ *              associated with in this thermal zone.
+ * @cdev:       thermal cooling device
+ */
+int thermal_zone_unbind_cooling_device(struct thermal_zone_device *tz,
+                                       int trip,
+                                       struct thermal_cooling_device *cdev)
+{
+        struct thermal_cooling_device_instance *pos, *next;
+
+        mutex_lock(&tz->lock);
+        list_for_each_entry_safe(pos, next, &tz->cooling_devices, node) {
+                if (pos->tz == tz && pos->trip == trip
+                    && pos->cdev == cdev) {
+                        list_del(&pos->node);
+                        mutex_unlock(&tz->lock);
+                        goto unbind;
+                }
+        }
+        mutex_unlock(&tz->lock);
+
+        return -ENODEV;
+
+      unbind:
+        device_remove_file(&tz->device, &pos->attr);
+        sysfs_remove_link(&tz->device.kobj, pos->name);
+        release_idr(&tz->idr, &tz->lock, pos->id);
+        kfree(pos);
+        return 0;
+}
+EXPORT_SYMBOL(thermal_zone_unbind_cooling_device);
+
+static void thermal_release(struct device *dev)
+{
+        struct thermal_zone_device *tz;
+        struct thermal_cooling_device *cdev;
+
+        if (!strncmp(dev->bus_id, "thermal_zone", sizeof "thermal_zone" - 1)) {
+                tz = to_thermal_zone(dev);
+                kfree(tz);
+        } else {
+                cdev = to_cooling_device(dev);
+                kfree(cdev);
+        }
+}
+
+static struct class thermal_class = {
+        .name = "thermal",
+        .dev_release = thermal_release,
+};
+
+/**
+ * thermal_cooling_device_register - register a new thermal cooling device
+ * @type:       the thermal cooling device type.
+ * @devdata:    device private data.
+ * @ops:                standard thermal cooling devices callbacks.
+ */
+struct thermal_cooling_device *thermal_cooling_device_register(char *type,
+                       void *devdata, struct thermal_cooling_device_ops *ops)
+{
+        struct thermal_cooling_device *cdev;
+        struct thermal_zone_device *pos;
+        int result;
+
+        if (strlen(type) >= THERMAL_NAME_LENGTH)
+                return NULL;
+
+        if (!ops || !ops->get_max_state || !ops->get_cur_state ||
+                !ops->set_cur_state)
+                return NULL;
+
+        cdev = kzalloc(sizeof(struct thermal_cooling_device), GFP_KERNEL);
+        if (!cdev)
+                return NULL;
+
+        result = get_idr(&thermal_cdev_idr, &thermal_idr_lock, &cdev->id);
+        if (result) {
+                kfree(cdev);
+                return NULL;
+        }
+
+        strcpy(cdev->type, type);
+        cdev->ops = ops;
+        cdev->device.class = &thermal_class;
+        cdev->devdata = devdata;
+        sprintf(cdev->device.bus_id, "cooling_device%d", cdev->id);
+        result = device_register(&cdev->device);
+        if (result) {
+                release_idr(&thermal_cdev_idr, &thermal_idr_lock, cdev->id);
+                kfree(cdev);
+                return NULL;
+        }
+
+        /* sys I/F */
+        if (type) {
+                result = device_create_file(&cdev->device,
+                                            &dev_attr_cdev_type);
+                if (result)
+                        goto unregister;
+        }
+
+        result = device_create_file(&cdev->device, &dev_attr_max_state);
+        if (result)
+                goto unregister;
+
+        result = device_create_file(&cdev->device, &dev_attr_cur_state);
+        if (result)
+                goto unregister;
+
+        mutex_lock(&thermal_list_lock);
+        list_add(&cdev->node, &thermal_cdev_list);
+        list_for_each_entry(pos, &thermal_tz_list, node) {
+                if (!pos->ops->bind)
+                        continue;
+                result = pos->ops->bind(pos, cdev);
+                if (result)
+                        break;
+
+        }
+        mutex_unlock(&thermal_list_lock);
+
+        if (!result)
+                return cdev;
+
+      unregister:
+        release_idr(&thermal_cdev_idr, &thermal_idr_lock, cdev->id);
+        device_unregister(&cdev->device);
+        return NULL;
+}
+EXPORT_SYMBOL(thermal_cooling_device_register);
+
+/**
+ * thermal_cooling_device_unregister - removes the registered thermal cooling device
+ *
+ * @cdev:       the thermal cooling device to remove.
+ *
+ * thermal_cooling_device_unregister() must be called when the device is no
+ * longer needed.
+ */
+void thermal_cooling_device_unregister(struct
+                                       thermal_cooling_device
+                                       *cdev)
+{
+        struct thermal_zone_device *tz;
+        struct thermal_cooling_device *pos = NULL;
+
+        if (!cdev)
+                return;
+
+        mutex_lock(&thermal_list_lock);
+        list_for_each_entry(pos, &thermal_cdev_list, node)
+            if (pos == cdev)
+                break;
+        if (pos != cdev) {
+                /* thermal cooling device not found */
+                mutex_unlock(&thermal_list_lock);
+                return;
+        }
+        list_del(&cdev->node);
+        list_for_each_entry(tz, &thermal_tz_list, node) {
+                if (!tz->ops->unbind)
+                        continue;
+                tz->ops->unbind(tz, cdev);
+        }
+        mutex_unlock(&thermal_list_lock);
+        if (cdev->type[0])
+                device_remove_file(&cdev->device,
+                                   &dev_attr_cdev_type);
+        device_remove_file(&cdev->device, &dev_attr_max_state);
+        device_remove_file(&cdev->device, &dev_attr_cur_state);
+
+        release_idr(&thermal_cdev_idr, &thermal_idr_lock, cdev->id);
+        device_unregister(&cdev->device);
+        return;
+}
+EXPORT_SYMBOL(thermal_cooling_device_unregister);
+
+/**
+ * thermal_zone_device_register - register a new thermal zone device
+ * @type:       the thermal zone device type
+ * @trips:      the number of trip points the thermal zone support
+ * @devdata:    private device data
+ * @ops:        standard thermal zone device callbacks
+ *
+ * thermal_zone_device_unregister() must be called when the device is no
+ * longer needed.
+ */
+struct thermal_zone_device *thermal_zone_device_register(char *type,
+                                        int trips, void *devdata,
+                                        struct thermal_zone_device_ops *ops)
+{
+        struct thermal_zone_device *tz;
+        struct thermal_cooling_device *pos;
+        int result;
+        int count;
+
+        if (strlen(type) >= THERMAL_NAME_LENGTH)
+                return NULL;
+
+        if (trips > THERMAL_MAX_TRIPS || trips < 0)
+                return NULL;
+
+        if (!ops || !ops->get_temp)
+                return NULL;
+
+        tz = kzalloc(sizeof(struct thermal_zone_device), GFP_KERNEL);
+        if (!tz)
+                return NULL;
+
+        INIT_LIST_HEAD(&tz->cooling_devices);
+        idr_init(&tz->idr);
+        mutex_init(&tz->lock);
+        result = get_idr(&thermal_tz_idr, &thermal_idr_lock, &tz->id);
+        if (result) {
+                kfree(tz);
+                return NULL;
+        }
+
+        strcpy(tz->type, type);
+        tz->ops = ops;
+        tz->device.class = &thermal_class;
+        tz->devdata = devdata;
+        tz->trips = trips;
+        sprintf(tz->device.bus_id, "thermal_zone%d", tz->id);
+        result = device_register(&tz->device);
+        if (result) {
+                release_idr(&thermal_tz_idr, &thermal_idr_lock, tz->id);
+                kfree(tz);
+                return NULL;
+        }
+
+        /* sys I/F */
+        if (type) {
+                result = device_create_file(&tz->device, &dev_attr_type);
+                if (result)
+                        goto unregister;
+        }
+
+        result = device_create_file(&tz->device, &dev_attr_temp);
+        if (result)
+                goto unregister;
+
+        if (ops->get_mode) {
+                result = device_create_file(&tz->device, &dev_attr_mode);
+                if (result)
+                        goto unregister;
+        }
+
+        for (count = 0; count < trips; count++) {
+                TRIP_POINT_ATTR_ADD(&tz->device, count, result);
+                if (result)
+                        goto unregister;
+        }
+
+        mutex_lock(&thermal_list_lock);
+        list_add_tail(&tz->node, &thermal_tz_list);
+        if (ops->bind)
+                list_for_each_entry(pos, &thermal_cdev_list, node) {
+                        result = ops->bind(tz, pos);
+                        if (result)
+                                break;
+                }
+        mutex_unlock(&thermal_list_lock);
+
+        if (!result)
+                return tz;
+
+      unregister:
+        release_idr(&thermal_tz_idr, &thermal_idr_lock, tz->id);
+        device_unregister(&tz->device);
+        return NULL;
+}
+EXPORT_SYMBOL(thermal_zone_device_register);
+
+/**
+ * thermal_device_unregister - removes the registered thermal zone device
+ *
+ * @tz: the thermal zone device to remove
+ */
+void thermal_zone_device_unregister(struct thermal_zone_device *tz)
+{
+        struct thermal_cooling_device *cdev;
+        struct thermal_zone_device *pos = NULL;
+        int count;
+
+        if (!tz)
+                return;
+
+        mutex_lock(&thermal_list_lock);
+        list_for_each_entry(pos, &thermal_tz_list, node)
+            if (pos == tz)
+                break;
+        if (pos != tz) {
+                /* thermal zone device not found */
+                mutex_unlock(&thermal_list_lock);
+                return;
+        }
+        list_del(&tz->node);
+        if (tz->ops->unbind)
+                list_for_each_entry(cdev, &thermal_cdev_list, node)
+                    tz->ops->unbind(tz, cdev);
+        mutex_unlock(&thermal_list_lock);
+
+        if (tz->type[0])
+                device_remove_file(&tz->device, &dev_attr_type);
+        device_remove_file(&tz->device, &dev_attr_temp);
+        if (tz->ops->get_mode)
+                device_remove_file(&tz->device, &dev_attr_mode);
+
+        for (count = 0; count < tz->trips; count++)
+                TRIP_POINT_ATTR_REMOVE(&tz->device, count);
+
+        release_idr(&thermal_tz_idr, &thermal_idr_lock, tz->id);
+        idr_destroy(&tz->idr);
+        mutex_destroy(&tz->lock);
+        device_unregister(&tz->device);
+        return;
+}
+EXPORT_SYMBOL(thermal_zone_device_unregister);
+
+static int __init thermal_init(void)
+{
+        int result = 0;
+
+        result = class_register(&thermal_class);
+        if (result) {
+                idr_destroy(&thermal_tz_idr);
+                idr_destroy(&thermal_cdev_idr);
+                mutex_destroy(&thermal_idr_lock);
+                mutex_destroy(&thermal_list_lock);
+        }
+        return result;
+}
+
+static void __exit thermal_exit(void)
+{
+        class_unregister(&thermal_class);
+        idr_destroy(&thermal_tz_idr);
+        idr_destroy(&thermal_cdev_idr);
+        mutex_destroy(&thermal_idr_lock);
+        mutex_destroy(&thermal_list_lock);
+}
+
+subsys_initcall(thermal_init);
+module_exit(thermal_exit);
diff --git a/include/linux/thermal.h b/include/linux/thermal.h
new file mode 100644
index 000000000000..e4b76c7afb51
--- /dev/null
+++ b/include/linux/thermal.h
@@ -0,0 +1,90 @@
+/*
+ *  thermal.h  ($Revision: 0 $)
+ *
+ *  Copyright (C) 2008  Intel Corp
+ *  Copyright (C) 2008  Zhang Rui <rui.zhang@intel.com>
+ *  Copyright (C) 2008  Sujith Thomas <sujith.thomas@intel.com>
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; version 2 of the License.
+ *
+ *  This program is distributed in the hope that it will be useful, but
+ *  WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, write to the Free Software Foundation, Inc.,
+ *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ */
+
+#ifndef __THERMAL_H__
+#define __THERMAL_H__
+
+#include <linux/idr.h>
+#include <linux/device.h>
+
+struct thermal_zone_device;
+struct thermal_cooling_device;
+
+struct thermal_zone_device_ops {
+        int (*bind) (struct thermal_zone_device *,
+                     struct thermal_cooling_device *);
+        int (*unbind) (struct thermal_zone_device *,
+                       struct thermal_cooling_device *);
+        int (*get_temp) (struct thermal_zone_device *, char *);
+        int (*get_mode) (struct thermal_zone_device *, char *);
+        int (*set_mode) (struct thermal_zone_device *, const char *);
+        int (*get_trip_type) (struct thermal_zone_device *, int, char *);
+        int (*get_trip_temp) (struct thermal_zone_device *, int, char *);
+};
+
+struct thermal_cooling_device_ops {
+        int (*get_max_state) (struct thermal_cooling_device *, char *);
+        int (*get_cur_state) (struct thermal_cooling_device *, char *);
+        int (*set_cur_state) (struct thermal_cooling_device *, unsigned int);
+};
+
+#define THERMAL_TRIPS_NONE -1
+#define THERMAL_MAX_TRIPS 10
+#define THERMAL_NAME_LENGTH 20
+struct thermal_cooling_device {
+        int id;
+        char type[THERMAL_NAME_LENGTH];
+        struct device device;
+        void *devdata;
+        struct thermal_cooling_device_ops *ops;
+        struct list_head node;
+};
+
+struct thermal_zone_device {
+        int id;
+        char type[THERMAL_NAME_LENGTH];
+        struct device device;
+        void *devdata;
+        int trips;
+        struct thermal_zone_device_ops *ops;
+        struct list_head cooling_devices;
+        struct idr idr;
+        struct mutex lock;      /* protect cooling devices list */
+        struct list_head node;
+};
+
+struct thermal_zone_device *thermal_zone_device_register(char *, int, void *,
+                                        struct thermal_zone_device_ops *);
+void thermal_zone_device_unregister(struct thermal_zone_device *);
+
+int thermal_zone_bind_cooling_device(struct thermal_zone_device *, int,
+                                     struct thermal_cooling_device *);
+int thermal_zone_unbind_cooling_device(struct thermal_zone_device *, int,
+                                       struct thermal_cooling_device *);
+
+struct thermal_cooling_device *thermal_cooling_device_register(char *, void *,
+                                        struct thermal_cooling_device_ops *);
+void thermal_cooling_device_unregister(struct thermal_cooling_device *);
+
+#endif                          /* __THERMAL_H__ */