drivers/acpi/thermal.c

/*
 *  acpi_thermal.c - ACPI Thermal Zone Driver ($Revision: 41 $)
 *
 *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
 *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@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; either version 2 of the License, or (at
 *  your option) any later version.
 *
 *  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.
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 *  This driver fully implements the ACPI thermal policy as described in the
 *  ACPI 2.0 Specification.
 *
 *  TBD: 1. Implement passive cooling hysteresis.
 *       2. Enhance passive cooling (CPU) states/limit interface to support
 *          concepts of 'multiple limiters', upper/lower limits, etc.
 *
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/proc_fs.h>
#include <linux/sched.h>
#include <linux/kmod.h>
#include <linux/seq_file.h>
#include <asm/uaccess.h>

#include <acpi/acpi_bus.h>
#include <acpi/acpi_drivers.h>

#define ACPI_THERMAL_COMPONENT		0x04000000
#define ACPI_THERMAL_CLASS		"thermal_zone"
#define ACPI_THERMAL_DRIVER_NAME	"ACPI Thermal Zone Driver"
#define ACPI_THERMAL_DEVICE_NAME	"Thermal Zone"
#define ACPI_THERMAL_FILE_STATE		"state"
#define ACPI_THERMAL_FILE_TEMPERATURE	"temperature"
#define ACPI_THERMAL_FILE_TRIP_POINTS	"trip_points"
#define ACPI_THERMAL_FILE_COOLING_MODE	"cooling_mode"
#define ACPI_THERMAL_FILE_POLLING_FREQ	"polling_frequency"
#define ACPI_THERMAL_NOTIFY_TEMPERATURE	0x80
#define ACPI_THERMAL_NOTIFY_THRESHOLDS	0x81
#define ACPI_THERMAL_NOTIFY_DEVICES	0x82
#define ACPI_THERMAL_NOTIFY_CRITICAL	0xF0
#define ACPI_THERMAL_NOTIFY_HOT		0xF1
#define ACPI_THERMAL_MODE_ACTIVE	0x00
#define ACPI_THERMAL_MODE_PASSIVE	0x01
#define ACPI_THERMAL_MODE_CRITICAL   	0xff
#define ACPI_THERMAL_PATH_POWEROFF	"/sbin/poweroff"

#define ACPI_THERMAL_MAX_ACTIVE	10
#define ACPI_THERMAL_MAX_LIMIT_STR_LEN 65

#define KELVIN_TO_CELSIUS(t)    (long)(((long)t-2732>=0) ? ((long)t-2732+5)/10 : ((long)t-2732-5)/10)
#define CELSIUS_TO_KELVIN(t)	((t+273)*10)

#define _COMPONENT		ACPI_THERMAL_COMPONENT
ACPI_MODULE_NAME("acpi_thermal")

MODULE_AUTHOR("Paul Diefenbaugh");
MODULE_DESCRIPTION(ACPI_THERMAL_DRIVER_NAME);
MODULE_LICENSE("GPL");

static int tzp;
module_param(tzp, int, 0);
MODULE_PARM_DESC(tzp, "Thermal zone polling frequency, in 1/10 seconds.\n");

static int acpi_thermal_add(struct acpi_device *device);
static int acpi_thermal_remove(struct acpi_device *device, int type);
static int acpi_thermal_resume(struct acpi_device *device, int state);
static int acpi_thermal_state_open_fs(struct inode *inode, struct file *file);
static int acpi_thermal_temp_open_fs(struct inode *inode, struct file *file);
static int acpi_thermal_trip_open_fs(struct inode *inode, struct file *file);
static ssize_t acpi_thermal_write_trip_points(struct file *,
					      const char __user *, size_t,
					      loff_t *);
static int acpi_thermal_cooling_open_fs(struct inode *inode, struct file *file);
static ssize_t acpi_thermal_write_cooling_mode(struct file *,
					       const char __user *, size_t,
					       loff_t *);
static int acpi_thermal_polling_open_fs(struct inode *inode, struct file *file);
static ssize_t acpi_thermal_write_polling(struct file *, const char __user *,
					  size_t, loff_t *);

static struct acpi_driver acpi_thermal_driver = {
	.name = ACPI_THERMAL_DRIVER_NAME,
	.class = ACPI_THERMAL_CLASS,
	.ids = ACPI_THERMAL_HID,
	.ops = {
		.add = acpi_thermal_add,
		.remove = acpi_thermal_remove,
		.resume = acpi_thermal_resume,
		},
};

struct acpi_thermal_state {
	u8 critical:1;
	u8 hot:1;
	u8 passive:1;
	u8 active:1;
	u8 reserved:4;
	int active_index;
};

struct acpi_thermal_state_flags {
	u8 valid:1;
	u8 enabled:1;
	u8 reserved:6;
};

struct acpi_thermal_critical {
	struct acpi_thermal_state_flags flags;
	unsigned long temperature;
};

struct acpi_thermal_hot {
	struct acpi_thermal_state_flags flags;
	unsigned long temperature;
};

struct acpi_thermal_passive {
	struct acpi_thermal_state_flags flags;
	unsigned long temperature;
	unsigned long tc1;
	unsigned long tc2;
	unsigned long tsp;
	struct acpi_handle_list devices;
};

struct acpi_thermal_active {
	struct acpi_thermal_state_flags flags;
	unsigned long temperature;
	struct acpi_handle_list devices;
};

struct acpi_thermal_trips {
	struct acpi_thermal_critical critical;
	struct acpi_thermal_hot hot;
	struct acpi_thermal_passive passive;
	struct acpi_thermal_active active[ACPI_THERMAL_MAX_ACTIVE];
};

struct acpi_thermal_flags {
	u8 cooling_mode:1;	/* _SCP */
	u8 devices:1;		/* _TZD */
	u8 reserved:6;
};

struct acpi_thermal {
	acpi_handle handle;
	acpi_bus_id name;
	unsigned long temperature;
	unsigned long last_temperature;
	unsigned long polling_frequency;
	u8 cooling_mode;
	volatile u8 zombie;
	struct acpi_thermal_flags flags;
	struct acpi_thermal_state state;
	struct acpi_thermal_trips trips;
	struct acpi_handle_list devices;
	struct timer_list timer;
};

static struct file_operations acpi_thermal_state_fops = {
	.open = acpi_thermal_state_open_fs,
	.read = seq_read,
	.llseek = seq_lseek,
	.release = single_release,
};

static struct file_operations acpi_thermal_temp_fops = {
	.open = acpi_thermal_temp_open_fs,
	.read = seq_read,
	.llseek = seq_lseek,
	.release = single_release,
};

static struct file_operations acpi_thermal_trip_fops = {
	.open = acpi_thermal_trip_open_fs,
	.read = seq_read,
	.write = acpi_thermal_write_trip_points,
	.llseek = seq_lseek,
	.release = single_release,
};

static struct file_operations acpi_thermal_cooling_fops = {
	.open = acpi_thermal_cooling_open_fs,
	.read = seq_read,
	.write = acpi_thermal_write_cooling_mode,
	.llseek = seq_lseek,
	.release = single_release,
};

static struct file_operations acpi_thermal_polling_fops = {
	.open = acpi_thermal_polling_open_fs,
	.read = seq_read,
	.write = acpi_thermal_write_polling,
	.llseek = seq_lseek,
	.release = single_release,
};

/* --------------------------------------------------------------------------
                             Thermal Zone Management
   -------------------------------------------------------------------------- */

static int acpi_thermal_get_temperature(struct acpi_thermal *tz)
{
	acpi_status status = AE_OK;

	ACPI_FUNCTION_TRACE("acpi_thermal_get_temperature");

	if (!tz)
		return_VALUE(-EINVAL);

	tz->last_temperature = tz->temperature;

	status =
	    acpi_evaluate_integer(tz->handle, "_TMP", NULL, &tz->temperature);
	if (ACPI_FAILURE(status))
		return_VALUE(-ENODEV);

	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Temperature is %lu dK\n",
			  tz->temperature));

	return_VALUE(0);
}

static int acpi_thermal_get_polling_frequency(struct acpi_thermal *tz)
{
	acpi_status status = AE_OK;

	ACPI_FUNCTION_TRACE("acpi_thermal_get_polling_frequency");

	if (!tz)
		return_VALUE(-EINVAL);

	status =
	    acpi_evaluate_integer(tz->handle, "_TZP", NULL,
				  &tz->polling_frequency);
	if (ACPI_FAILURE(status))
		return_VALUE(-ENODEV);

	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Polling frequency is %lu dS\n",
			  tz->polling_frequency));

	return_VALUE(0);
}

static int acpi_thermal_set_polling(struct acpi_thermal *tz, int seconds)
{
	ACPI_FUNCTION_TRACE("acpi_thermal_set_polling");

	if (!tz)
		return_VALUE(-EINVAL);

	tz->polling_frequency = seconds * 10;	/* Convert value to deci-seconds */

	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
			  "Polling frequency set to %lu seconds\n",
			  tz->polling_frequency));

	return_VALUE(0);
}

static int acpi_thermal_set_cooling_mode(struct acpi_thermal *tz, int mode)
{
	acpi_status status = AE_OK;
	union acpi_object arg0 = { ACPI_TYPE_INTEGER };
	struct acpi_object_list arg_list = { 1, &arg0 };
	acpi_handle handle = NULL;

	ACPI_FUNCTION_TRACE("acpi_thermal_set_cooling_mode");

	if (!tz)
		return_VALUE(-EINVAL);

	status = acpi_get_handle(tz->handle, "_SCP", &handle);
	if (ACPI_FAILURE(status)) {
		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "_SCP not present\n"));
		return_VALUE(-ENODEV);
	}

	arg0.integer.value = mode;

	status = acpi_evaluate_object(handle, NULL, &arg_list, NULL);
	if (ACPI_FAILURE(status))
		return_VALUE(-ENODEV);

	tz->cooling_mode = mode;

	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Cooling mode [%s]\n",
			  mode ? "passive" : "active"));

	return_VALUE(0);
}

static int acpi_thermal_get_trip_points(struct acpi_thermal *tz)
{
	acpi_status status = AE_OK;
	int i = 0;

	ACPI_FUNCTION_TRACE("acpi_thermal_get_trip_points");

	if (!tz)
		return_VALUE(-EINVAL);

	/* Critical Shutdown (required) */

	status = acpi_evaluate_integer(tz->handle, "_CRT", NULL,
				       &tz->trips.critical.temperature);
	if (ACPI_FAILURE(status)) {
		tz->trips.critical.flags.valid = 0;
		ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "No critical threshold\n"));
		return_VALUE(-ENODEV);
	} else {
		tz->trips.critical.flags.valid = 1;
		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
				  "Found critical threshold [%lu]\n",
				  tz->trips.critical.temperature));
	}

	/* Critical Sleep (optional) */

	status =
	    acpi_evaluate_integer(tz->handle, "_HOT", NULL,
				  &tz->trips.hot.temperature);
	if (ACPI_FAILURE(status)) {
		tz->trips.hot.flags.valid = 0;
		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No hot threshold\n"));
	} else {
		tz->trips.hot.flags.valid = 1;
		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found hot threshold [%lu]\n",
				  tz->trips.hot.temperature));
	}

	/* Passive: Processors (optional) */

	status =
	    acpi_evaluate_integer(tz->handle, "_PSV", NULL,
				  &tz->trips.passive.temperature);
	if (ACPI_FAILURE(status)) {
		tz->trips.passive.flags.valid = 0;
		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No passive threshold\n"));
	} else {
		tz->trips.passive.flags.valid = 1;

		status =
		    acpi_evaluate_integer(tz->handle, "_TC1", NULL,
					  &tz->trips.passive.tc1);
		if (ACPI_FAILURE(status))
			tz->trips.passive.flags.valid = 0;

		status =
		    acpi_evaluate_integer(tz->handle, "_TC2", NULL,
					  &tz->trips.passive.tc2);
		if (ACPI_FAILURE(status))
			tz->trips.passive.flags.valid = 0;

		status =
		    acpi_evaluate_integer(tz->handle, "_TSP", NULL,
					  &tz->trips.passive.tsp);
		if (ACPI_FAILURE(status))
			tz->trips.passive.flags.valid = 0;

		status =
		    acpi_evaluate_reference(tz->handle, "_PSL", NULL,
					    &tz->trips.passive.devices);
		if (ACPI_FAILURE(status))
			tz->trips.passive.flags.valid = 0;

		if (!tz->trips.passive.flags.valid)
			ACPI_DEBUG_PRINT((ACPI_DB_WARN,
					  "Invalid passive threshold\n"));
		else
			ACPI_DEBUG_PRINT((ACPI_DB_INFO,
					  "Found passive threshold [%lu]\n",
					  tz->trips.passive.temperature));
	}

	/* Active: Fans, etc. (optional) */

	for (i = 0; i < ACPI_THERMAL_MAX_ACTIVE; i++) {

		char name[5] = { '_', 'A', 'C', ('0' + i), '\0' };

		status =
		    acpi_evaluate_integer(tz->handle, name, NULL,
					  &tz->trips.active[i].temperature);
		if (ACPI_FAILURE(status))
			break;

		name[2] = 'L';
		status =
		    acpi_evaluate_reference(tz->handle, name, NULL,
					    &tz->trips.active[i].devices);
		if (ACPI_SUCCESS(status)) {
			tz->trips.active[i].flags.valid = 1;
			ACPI_DEBUG_PRINT((ACPI_DB_INFO,
					  "Found active threshold [%d]:[%lu]\n",
					  i, tz->trips.active[i].temperature));
		} else
			ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
					  "Invalid active threshold [%d]\n",
					  i));
	}

	return_VALUE(0);
}

static int acpi_thermal_get_devices(struct acpi_thermal *tz)
{
	acpi_status status = AE_OK;

	ACPI_FUNCTION_TRACE("acpi_thermal_get_devices");

	if (!tz)
		return_VALUE(-EINVAL);

	status =
	    acpi_evaluate_reference(tz->handle, "_TZD", NULL, &tz->devices);
	if (ACPI_FAILURE(status))
		return_VALUE(-ENODEV);

	return_VALUE(0);
}

static int acpi_thermal_call_usermode(char *path)
{
	char *argv[2] = { NULL, NULL };
	char *envp[3] = { NULL, NULL, NULL };

	ACPI_FUNCTION_TRACE("acpi_thermal_call_usermode");

	if (!path)
		return_VALUE(-EINVAL);

	argv[0] = path;

	/* minimal command environment */
	envp[0] = "HOME=/";
	envp[1] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";

	call_usermodehelper(argv[0], argv, envp, 0);

	return_VALUE(0);
}

static int acpi_thermal_critical(struct acpi_thermal *tz)
{
	int result = 0;
	struct acpi_device *device = NULL;

	ACPI_FUNCTION_TRACE("acpi_thermal_critical");

	if (!tz || !tz->trips.critical.flags.valid)
		return_VALUE(-EINVAL);

	if (tz->temperature >= tz->trips.critical.temperature) {
		ACPI_DEBUG_PRINT((ACPI_DB_WARN, "Critical trip point\n"));
		tz->trips.critical.flags.enabled = 1;
	} else if (tz->trips.critical.flags.enabled)
		tz->trips.critical.flags.enabled = 0;

	result = acpi_bus_get_device(tz->handle, &device);
	if (result)
		return_VALUE(result);

	printk(KERN_EMERG
	       "Critical temperature reached (%ld C), shutting down.\n",
	       KELVIN_TO_CELSIUS(tz->temperature));
	acpi_bus_generate_event(device, ACPI_THERMAL_NOTIFY_CRITICAL,
				tz->trips.critical.flags.enabled);

	acpi_thermal_call_usermode(ACPI_THERMAL_PATH_POWEROFF);

	return_VALUE(0);
}

static int acpi_thermal_hot(struct acpi_thermal *tz)
{
	int result = 0;
	struct acpi_device *device = NULL;

	ACPI_FUNCTION_TRACE("acpi_thermal_hot");

	if (!tz || !tz->trips.hot.flags.valid)
		return_VALUE(-EINVAL);

	if (tz->temperature >= tz->trips.hot.temperature) {
		ACPI_DEBUG_PRINT((ACPI_DB_WARN, "Hot trip point\n"));
		tz->trips.hot.flags.enabled = 1;
	} else if (tz->trips.hot.flags.enabled)
		tz->trips.hot.flags.enabled = 0;

	result = acpi_bus_get_device(tz->handle, &device);
	if (result)
		return_VALUE(result);

	acpi_bus_generate_event(device, ACPI_THERMAL_NOTIFY_HOT,
				tz->trips.hot.flags.enabled);

	/* TBD: Call user-mode "sleep(S4)" function */

	return_VALUE(0);
}

static void acpi_thermal_passive(struct acpi_thermal *tz)
{
	int result = 1;
	struct acpi_thermal_passive *passive = NULL;
	int trend = 0;
	int i = 0;

	ACPI_FUNCTION_TRACE("acpi_thermal_passive");

	if (!tz || !tz->trips.passive.flags.valid)
		return;

	passive = &(tz->trips.passive);

	/*
	 * Above Trip?
	 * -----------
	 * Calculate the thermal trend (using the passive cooling equation)
	 * and modify the performance limit for all passive cooling devices
	 * accordingly.  Note that we assume symmetry.
	 */
	if (tz->temperature >= passive->temperature) {
		trend =
		    (passive->tc1 * (tz->temperature - tz->last_temperature)) +
		    (passive->tc2 * (tz->temperature - passive->temperature));
		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
				  "trend[%d]=(tc1[%lu]*(tmp[%lu]-last[%lu]))+(tc2[%lu]*(tmp[%lu]-psv[%lu]))\n",
				  trend, passive->tc1, tz->temperature,
				  tz->last_temperature, passive->tc2,
				  tz->temperature, passive->temperature));
		passive->flags.enabled = 1;
		/* Heating up? */
		if (trend > 0)
			for (i = 0; i < passive->devices.count; i++)
				acpi_processor_set_thermal_limit(passive->
								 devices.
								 handles[i],
								 ACPI_PROCESSOR_LIMIT_INCREMENT);
		/* Cooling off? */
		else if (trend < 0) {
			for (i = 0; i < passive->devices.count; i++)
				/*
				 * assume that we are on highest
				 * freq/lowest thrott and can leave
				 * passive mode, even in error case
				 */
				if (!acpi_processor_set_thermal_limit
				    (passive->devices.handles[i],
				     ACPI_PROCESSOR_LIMIT_DECREMENT))
					result = 0;
			/*
			 * Leave cooling mode, even if the temp might
			 * higher than trip point This is because some
			 * machines might have long thermal polling
			 * frequencies (tsp) defined. We will fall back
			 * into passive mode in next cycle (probably quicker)
			 */
			if (result) {
				passive->flags.enabled = 0;
				ACPI_DEBUG_PRINT((ACPI_DB_INFO,
						  "Disabling passive cooling, still above threshold,"
						  " but we are cooling down\n"));
			}
		}
		return;
	}

	/*
	 * Below Trip?
	 * -----------
	 * Implement passive cooling hysteresis to slowly increase performance
	 * and avoid thrashing around the passive trip point.  Note that we
	 * assume symmetry.
	 */
	if (!passive->flags.enabled)
		return;
	for (i = 0; i < passive->devices.count; i++)
		if (!acpi_processor_set_thermal_limit
		    (passive->devices.handles[i],
		     ACPI_PROCESSOR_LIMIT_DECREMENT))
			result = 0;
	if (result) {
		passive->flags.enabled = 0;
		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
				  "Disabling passive cooling (zone is cool)\n"));
	}
}

static void acpi_thermal_active(struct acpi_thermal *tz)
{
	int result = 0;
	struct acpi_thermal_active *active = NULL;
	int i = 0;
	int j = 0;
	unsigned long maxtemp = 0;

	ACPI_FUNCTION_TRACE("acpi_thermal_active");

	if (!tz)
		return;

	for (i = 0; i < ACPI_THERMAL_MAX_ACTIVE; i++) {
		active = &(tz->trips.active[i]);
		if (!active || !active->flags.valid)
			break;
		if (tz->temperature >= active->temperature) {
			/*
			 * Above Threshold?
			 * ----------------
			 * If not already enabled, turn ON all cooling devices
			 * associated with this active threshold.
			 */
			if (active->temperature > maxtemp)
				tz->state.active_index = i;
			maxtemp = active->temperature;
			if (active->flags.enabled)
				continue;
			for (j = 0; j < active->devices.count; j++) {
				result =
				    acpi_bus_set_power(active->devices.
						       handles[j],
						       ACPI_STATE_D0);
				if (result) {
					ACPI_DEBUG_PRINT((ACPI_DB_WARN,
							  "Unable to turn cooling device [%p] 'on'\n",
							  active->devices.
							  handles[j]));
					continue;
				}
				active->flags.enabled = 1;
				ACPI_DEBUG_PRINT((ACPI_DB_INFO,
						  "Cooling device [%p] now 'on'\n",
						  active->devices.handles[j]));
			}
			continue;
		}
		if (!active->flags.enabled)
			continue;
		/*
		 * Below Threshold?
		 * ----------------
		 * Turn OFF all cooling devices associated with this
		 * threshold.
		 */
		for (j = 0; j < active->devices.count; j++) {
			result = acpi_bus_set_power(active->devices.handles[j],
						    ACPI_STATE_D3);
			if (result) {
				ACPI_DEBUG_PRINT((ACPI_DB_WARN,
						  "Unable to turn cooling device [%p] 'off'\n",
						  active->devices.handles[j]));
				continue;
			}
			active->flags.enabled = 0;
			ACPI_DEBUG_PRINT((ACPI_DB_INFO,
					  "Cooling device [%p] now 'off'\n",
					  active->devices.handles[j]));
		}
	}
}

static void acpi_thermal_check(void *context);

static void acpi_thermal_run(unsigned long data)
{
	struct acpi_thermal *tz = (struct acpi_thermal *)data;
	if (!tz->zombie)
		acpi_os_queue_for_execution(OSD_PRIORITY_GPE,
					    acpi_thermal_check, (void *)data);
}

static void acpi_thermal_check(void *data)
{
	int result = 0;
	struct acpi_thermal *tz = (struct acpi_thermal *)data;
	unsigned long sleep_time = 0;
	int i = 0;
	struct acpi_thermal_state state;

	ACPI_FUNCTION_TRACE("acpi_thermal_check");

	if (!tz) {
		ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Invalid (NULL) context.\n"));
		return_VOID;
	}

	state = tz->state;

	result = acpi_thermal_get_temperature(tz);
	if (result)
		return_VOID;

	memset(&tz->state, 0, sizeof(tz->state));

	/*
	 * Check Trip Points
	 * -----------------
	 * Compare the current temperature to the trip point values to see
	 * if we've entered one of the thermal policy states.  Note that
	 * this function determines when a state is entered, but the 
	 * individual policy decides when it is exited (e.g. hysteresis).
	 */
	if (tz->trips.critical.flags.valid)
		state.critical |=
		    (tz->temperature >= tz->trips.critical.temperature);
	if (tz->trips.hot.flags.valid)
		state.hot |= (tz->temperature >= tz->trips.hot.temperature);
	if (tz->trips.passive.flags.valid)
		state.passive |=
		    (tz->temperature >= tz->trips.passive.temperature);
	for (i = 0; i < ACPI_THERMAL_MAX_ACTIVE; i++)
		if (tz->trips.active[i].flags.valid)
			state.active |=
			    (tz->temperature >=
			     tz->trips.active[i].temperature);

	/*
	 * Invoke Policy
	 * -------------
	 * Separated from the above check to allow individual policy to 
	 * determine when to exit a given state.
	 */
	if (state.critical)
		acpi_thermal_critical(tz);
	if (state.hot)
		acpi_thermal_hot(tz);
	if (state.passive)
		acpi_thermal_passive(tz);
	if (state.active)
		acpi_thermal_active(tz);

	/*
	 * Calculate State
	 * ---------------
	 * Again, separated from the above two to allow independent policy
	 * decisions.
	 */
	tz->state.critical = tz->trips.critical.flags.enabled;
	tz->state.hot = tz->trips.hot.flags.enabled;
	tz->state.passive = tz->trips.passive.flags.enabled;
	tz->state.active = 0;
	for (i = 0; i < ACPI_THERMAL_MAX_ACTIVE; i++)
		tz->state.active |= tz->trips.active[i].flags.enabled;

	/*
	 * Calculate Sleep Time
	 * --------------------
	 * If we're in the passive state, use _TSP's value.  Otherwise
	 * use the default polling frequency (e.g. _TZP).  If no polling
	 * frequency is specified then we'll wait forever (at least until
	 * a thermal event occurs).  Note that _TSP and _TZD values are
	 * given in 1/10th seconds (we must covert to milliseconds).
	 */
	if (tz->state.passive)
		sleep_time = tz->trips.passive.tsp * 100;
	else if (tz->polling_frequency > 0)
		sleep_time = tz->polling_frequency * 100;

	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "%s: temperature[%lu] sleep[%lu]\n",
			  tz->name, tz->temperature, sleep_time));

	/*
	 * Schedule Next Poll
	 * ------------------
	 */
	if (!sleep_time) {
		if (timer_pending(&(tz->timer)))
			del_timer(&(tz->timer));
	} else {
		if (timer_pending(&(tz->timer)))
			mod_timer(&(tz->timer), (HZ * sleep_time) / 1000);
		else {
			tz->timer.data = (unsigned long)tz;
			tz->timer.function = acpi_thermal_run;
			tz->timer.expires = jiffies + (HZ * sleep_time) / 1000;
			add_timer(&(tz->timer));
		}
	}

	return_VOID;
}

/* --------------------------------------------------------------------------
                              FS Interface (/proc)
   -------------------------------------------------------------------------- */

static struct proc_dir_entry *acpi_thermal_dir;

static int acpi_thermal_state_seq_show(struct seq_file *seq, void *offset)
{
	struct acpi_thermal *tz = (struct acpi_thermal *)seq->private;

	ACPI_FUNCTION_TRACE("acpi_thermal_state_seq_show");

	if (!tz)
		goto end;

	seq_puts(seq, "state:                   ");

	if (!tz->state.critical && !tz->state.hot && !tz->state.passive
	    && !tz->state.active)
		seq_puts(seq, "ok\n");
	else {
		if (tz->state.critical)
			seq_puts(seq, "critical ");
		if (tz->state.hot)
			seq_puts(seq, "hot ");
		if (tz->state.passive)
			seq_puts(seq, "passive ");
		if (tz->state.active)
			seq_printf(seq, "active[%d]", tz->state.active_index);
		seq_puts(seq, "\n");
	}

      end:
	return_VALUE(0);
}

static int acpi_thermal_state_open_fs(struct inode *inode, struct file *file)
{
	return single_open(file, acpi_thermal_state_seq_show, PDE(inode)->data);
}

static int acpi_thermal_temp_seq_show(struct seq_file *seq, void *offset)
{
	int result = 0;
	struct acpi_thermal *tz = (struct acpi_thermal *)seq->private;

	ACPI_FUNCTION_TRACE("acpi_thermal_temp_seq_show");

	if (!tz)
		goto end;

	result = acpi_thermal_get_temperature(tz);
	if (result)
		goto end;

	seq_printf(seq, "temperature:             %ld C\n",
		   KELVIN_TO_CELSIUS(tz->temperature));

      end:
	return_VALUE(0);
}

static int acpi_thermal_temp_open_fs(struct inode *inode, struct file *file)
{
	return single_open(file, acpi_thermal_temp_seq_show, PDE(inode)->data);
}

static int acpi_thermal_trip_seq_show(struct seq_file *seq, void *offset)
{
	struct acpi_thermal *tz = (struct acpi_thermal *)seq->private;
	int i = 0;
	int j = 0;

	ACPI_FUNCTION_TRACE("acpi_thermal_trip_seq_show");

	if (!tz)
		goto end;

	if (tz->trips.critical.flags.valid)
		seq_printf(seq, "critical (S5):           %ld C\n",
			   KELVIN_TO_CELSIUS(tz->trips.critical.temperature));

	if (tz->trips.hot.flags.valid)
		seq_printf(seq, "hot (S4):                %ld C\n",
			   KELVIN_TO_CELSIUS(tz->trips.hot.temperature));

	if (tz->trips.passive.flags.valid) {
		seq_printf(seq,
			   "passive:                 %ld C: tc1=%lu tc2=%lu tsp=%lu devices=",
			   KELVIN_TO_CELSIUS(tz->trips.passive.temperature),
			   tz->trips.passive.tc1, tz->trips.passive.tc2,
			   tz->trips.passive.tsp);
		for (j = 0; j < tz->trips.passive.devices.count; j++) {

			seq_printf(seq, "0x%p ",
				   tz->trips.passive.devices.handles[j]);
		}
		seq_puts(seq, "\n");
	}

	for (i = 0; i < ACPI_THERMAL_MAX_ACTIVE; i++) {
		if (!(tz->trips.active[i].flags.valid))
			break;
		seq_printf(seq, "active[%d]:               %ld C: devices=",
			   i,
			   KELVIN_TO_CELSIUS(tz->trips.active[i].temperature));
		for (j = 0; j < tz->trips.active[i].devices.count; j++)
			seq_printf(seq, "0x%p ",
				   tz->trips.active[i].devices.handles[j]);
		seq_puts(seq, "\n");
	}

      end:
	return_VALUE(0);
}

static int acpi_thermal_trip_open_fs(struct inode *inode, struct file *file)
{
	return single_open(file, acpi_thermal_trip_seq_show, PDE(inode)->data);
}

static ssize_t
acpi_thermal_write_trip_points(struct file *file,
			       const char __user * buffer,
			       size_t count, loff_t * ppos)
{
	struct seq_file *m = (struct seq_file *)file->private_data;
	struct acpi_thermal *tz = (struct acpi_thermal *)m->private;

	char *limit_string;
	int num, critical, hot, passive;
	int *active;
	int i = 0;

	ACPI_FUNCTION_TRACE("acpi_thermal_write_trip_points");

	limit_string = kmalloc(ACPI_THERMAL_MAX_LIMIT_STR_LEN, GFP_KERNEL);
	if (!limit_string)
		return_VALUE(-ENOMEM);

	memset(limit_string, 0, ACPI_THERMAL_MAX_LIMIT_STR_LEN);

	active = kmalloc(ACPI_THERMAL_MAX_ACTIVE * sizeof(int), GFP_KERNEL);
	if (!active)
		return_VALUE(-ENOMEM);

	if (!tz || (count > ACPI_THERMAL_MAX_LIMIT_STR_LEN - 1)) {
		ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Invalid argument\n"));
		count = -EINVAL;
		goto end;
	}

	if (copy_from_user(limit_string, buffer, count)) {
		ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Invalid data\n"));
		count = -EFAULT;
		goto end;
	}

	limit_string[count] = '\0';

	num = sscanf(limit_string, "%d:%d:%d:%d:%d:%d:%d:%d:%d:%d:%d:%d:%d",
		     &critical, &hot, &passive,
		     &active[0], &active[1], &active[2], &active[3], &active[4],
		     &active[5], &active[6], &active[7], &active[8],
		     &active[9]);
	if (!(num >= 5 && num < (ACPI_THERMAL_MAX_ACTIVE + 3))) {
		ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Invalid data format\n"));
		count = -EINVAL;
		goto end;
	}

	tz->trips.critical.temperature = CELSIUS_TO_KELVIN(critical);
	tz->trips.hot.temperature = CELSIUS_TO_KELVIN(hot);
	tz->trips.passive.temperature = CELSIUS_TO_KELVIN(passive);
	for (i = 0; i < num - 3; i++) {
		if (!(tz->trips.active[i].flags.valid))
			break;
		tz->trips.active[i].temperature = CELSIUS_TO_KELVIN(active[i]);
	}

      end:
	kfree(active);
	kfree(limit_string);
	return_VALUE(count);
}

static int acpi_thermal_cooling_seq_show(struct seq_file *seq, void *offset)
{
	struct acpi_thermal *tz = (struct acpi_thermal *)seq->private;

	ACPI_FUNCTION_TRACE("acpi_thermal_cooling_seq_show");

	if (!tz)
		goto end;

	if (!tz->flags.cooling_mode) {
		seq_puts(seq, "<setting not supported>\n");
	}

	if (tz->cooling_mode == ACPI_THERMAL_MODE_CRITICAL)
		seq_printf(seq, "cooling mode:	critical\n");
	else
		seq_printf(seq, "cooling mode:	%s\n",
			   tz->cooling_mode ? "passive" : "active");

      end:
	return_VALUE(0);
}

static int acpi_thermal_cooling_open_fs(struct inode *inode, struct file *file)
{
	return single_open(file, acpi_thermal_cooling_seq_show,
			   PDE(inode)->data);
}

static ssize_t
acpi_thermal_write_cooling_mode(struct file *file,
				const char __user * buffer,
				size_t count, loff_t * ppos)
{
	struct seq_file *m = (struct seq_file *)file->private_data;
	struct acpi_thermal *tz = (struct acpi_thermal *)m->private;
	int result = 0;
	char mode_string[12] = { '\0' };

	ACPI_FUNCTION_TRACE("acpi_thermal_write_cooling_mode");

	if (!tz || (count > sizeof(mode_string) - 1))
		return_VALUE(-EINVAL);

	if (!tz->flags.cooling_mode)
		return_VALUE(-ENODEV);

	if (copy_from_user(mode_string, buffer, count))
		return_VALUE(-EFAULT);

	mode_string[count] = '\0';

	result = acpi_thermal_set_cooling_mode(tz,
					       simple_strtoul(mode_string, NULL,
							      0));
	if (result)
		return_VALUE(result);

	acpi_thermal_check(tz);

	return_VALUE(count);
}

static int acpi_thermal_polling_seq_show(struct seq_file *seq, void *offset)
{
	struct acpi_thermal *tz = (struct acpi_thermal *)seq->private;

	ACPI_FUNCTION_TRACE("acpi_thermal_polling_seq_show");

	if (!tz)
		goto end;

	if (!tz->polling_frequency) {
		seq_puts(seq, "<polling disabled>\n");
		goto end;
	}

	seq_printf(seq, "polling frequency:       %lu seconds\n",
		   (tz->polling_frequency / 10));

      end:
	return_VALUE(0);
}

static int acpi_thermal_polling_open_fs(struct inode *inode, struct file *file)
{
	return single_open(file, acpi_thermal_polling_seq_show,
			   PDE(inode)->data);
}

static ssize_t
acpi_thermal_write_polling(struct file *file,
			   const char __user * buffer,
			   size_t count, loff_t * ppos)
{
	struct seq_file *m = (struct seq_file *)file->private_data;
	struct acpi_thermal *tz = (struct acpi_thermal *)m->private;
	int result = 0;
	char polling_string[12] = { '\0' };
	int seconds = 0;

	ACPI_FUNCTION_TRACE("acpi_thermal_write_polling");

	if (!tz || (count > sizeof(polling_string) - 1))
		return_VALUE(-EINVAL);

	if (copy_from_user(polling_string, buffer, count))
		return_VALUE(-EFAULT);

	polling_string[count] = '\0';

	seconds = simple_strtoul(polling_string, NULL, 0);

	result = acpi_thermal_set_polling(tz, seconds);
	if (result)
		return_VALUE(result);

	acpi_thermal_check(tz);

	return_VALUE(count);
}

static int acpi_thermal_add_fs(struct acpi_device *device)
{
	struct proc_dir_entry *entry = NULL;

	ACPI_FUNCTION_TRACE("acpi_thermal_add_fs");

	if (!acpi_device_dir(device)) {
		acpi_device_dir(device) = proc_mkdir(acpi_device_bid(device),
						     acpi_thermal_dir);
		if (!acpi_device_dir(device))
			return_VALUE(-ENODEV);
		acpi_device_dir(device)->owner = THIS_MODULE;
	}

	/* 'state' [R] */
	entry = create_proc_entry(ACPI_THERMAL_FILE_STATE,
				  S_IRUGO, acpi_device_dir(device));
	if (!entry)
		ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
				  "Unable to create '%s' fs entry\n",
				  ACPI_THERMAL_FILE_STATE));
	else {
		entry->proc_fops = &acpi_thermal_state_fops;
		entry->data = acpi_driver_data(device);
		entry->owner = THIS_MODULE;
	}

	/* 'temperature' [R] */
	entry = create_proc_entry(ACPI_THERMAL_FILE_TEMPERATURE,
				  S_IRUGO, acpi_device_dir(device));
	if (!entry)
		ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
				  "Unable to create '%s' fs entry\n",
				  ACPI_THERMAL_FILE_TEMPERATURE));
	else {
		entry->proc_fops = &acpi_thermal_temp_fops;
		entry->data = acpi_driver_data(device);
		entry->owner = THIS_MODULE;
	}

	/* 'trip_points' [R/W] */
	entry = create_proc_entry(ACPI_THERMAL_FILE_TRIP_POINTS,
				  S_IFREG | S_IRUGO | S_IWUSR,
				  acpi_device_dir(device));
	if (!entry)
		ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
				  "Unable to create '%s' fs entry\n",
				  ACPI_THERMAL_FILE_TRIP_POINTS));
	else {
		entry->proc_fops = &acpi_thermal_trip_fops;
		entry->data = acpi_driver_data(device);
		entry->owner = THIS_MODULE;
	}

	/* 'cooling_mode' [R/W] */
	entry = create_proc_entry(ACPI_THERMAL_FILE_COOLING_MODE,
				  S_IFREG | S_IRUGO | S_IWUSR,
				  acpi_device_dir(device));
	if (!entry)
		ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
				  "Unable to create '%s' fs entry\n",
				  ACPI_THERMAL_FILE_COOLING_MODE));
	else {
		entry->proc_fops = &acpi_thermal_cooling_fops;
		entry->data = acpi_driver_data(device);
		entry->owner = THIS_MODULE;
	}

	/* 'polling_frequency' [R/W] */
	entry = create_proc_entry(ACPI_THERMAL_FILE_POLLING_FREQ,
				  S_IFREG | S_IRUGO | S_IWUSR,
				  acpi_device_dir(device));
	if (!entry)
		ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
				  "Unable to create '%s' fs entry\n",
				  ACPI_THERMAL_FILE_POLLING_FREQ));
	else {
		entry->proc_fops = &acpi_thermal_polling_fops;
		entry->data = acpi_driver_data(device);
		entry->owner = THIS_MODULE;
	}

	return_VALUE(0);
}

static int acpi_thermal_remove_fs(struct acpi_device *device)
{
	ACPI_FUNCTION_TRACE("acpi_thermal_remove_fs");

	if (acpi_device_dir(device)) {
		remove_proc_entry(ACPI_THERMAL_FILE_POLLING_FREQ,
				  acpi_device_dir(device));
		remove_proc_entry(ACPI_THERMAL_FILE_COOLING_MODE,
				  acpi_device_dir(device));
		remove_proc_entry(ACPI_THERMAL_FILE_TRIP_POINTS,
				  acpi_device_dir(device));
		remove_proc_entry(ACPI_THERMAL_FILE_TEMPERATURE,
				  acpi_device_dir(device));
		remove_proc_entry(ACPI_THERMAL_FILE_STATE,
				  acpi_device_dir(device));
		remove_proc_entry(acpi_device_bid(device), acpi_thermal_dir);
		acpi_device_dir(device) = NULL;
	}

	return_VALUE(0);
}

/* --------------------------------------------------------------------------
                                 Driver Interface
   -------------------------------------------------------------------------- */

static void acpi_thermal_notify(acpi_handle handle, u32 event, void *data)
{
	struct acpi_thermal *tz = (struct acpi_thermal *)data;
	struct acpi_device *device = NULL;

	ACPI_FUNCTION_TRACE("acpi_thermal_notify");

	if (!tz)
		return_VOID;

	if (acpi_bus_get_device(tz->handle, &device))
		return_VOID;

	switch (event) {
	case ACPI_THERMAL_NOTIFY_TEMPERATURE:
		acpi_thermal_check(tz);
		break;
	case ACPI_THERMAL_NOTIFY_THRESHOLDS:
		acpi_thermal_get_trip_points(tz);
		acpi_thermal_check(tz);
		acpi_bus_generate_event(device, event, 0);
		break;
	case ACPI_THERMAL_NOTIFY_DEVICES:
		if (tz->flags.devices)
			acpi_thermal_get_devices(tz);
		acpi_bus_generate_event(device, event, 0);
		break;
	default:
		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
				  "Unsupported event [0x%x]\n", event));
		break;
	}

	return_VOID;
}

static int acpi_thermal_get_info(struct acpi_thermal *tz)
{
	int result = 0;

	ACPI_FUNCTION_TRACE("acpi_thermal_get_info");

	if (!tz)
		return_VALUE(-EINVAL);

	/* Get temperature [_TMP] (required) */
	result = acpi_thermal_get_temperature(tz);
	if (result)
		return_VALUE(result);

	/* Get trip points [_CRT, _PSV, etc.] (required) */
	result = acpi_thermal_get_trip_points(tz);
	if (result)
		return_VALUE(result);

	/* Set the cooling mode [_SCP] to active cooling (default) */
	result = acpi_thermal_set_cooling_mode(tz, ACPI_THERMAL_MODE_ACTIVE);
	if (!result)
		tz->flags.cooling_mode = 1;
	else {
		/* Oh,we have not _SCP method.
		   Generally show cooling_mode by _ACx, _PSV,spec 12.2 */
		tz->flags.cooling_mode = 0;
		if (tz->trips.active[0].flags.valid
		    && tz->trips.passive.flags.valid) {
			if (tz->trips.passive.temperature >
			    tz->trips.active[0].temperature)
				tz->cooling_mode = ACPI_THERMAL_MODE_ACTIVE;
			else
				tz->cooling_mode = ACPI_THERMAL_MODE_PASSIVE;
		} else if (!tz->trips.active[0].flags.valid
			   && tz->trips.passive.flags.valid) {
			tz->cooling_mode = ACPI_THERMAL_MODE_PASSIVE;
		} else if (tz->trips.active[0].flags.valid
			   && !tz->trips.passive.flags.valid) {
			tz->cooling_mode = ACPI_THERMAL_MODE_ACTIVE;
		} else {
			/* _ACx and _PSV are optional, but _CRT is required */
			tz->cooling_mode = ACPI_THERMAL_MODE_CRITICAL;
		}
	}

	/* Get default polling frequency [_TZP] (optional) */
	if (tzp)
		tz->polling_frequency = tzp;
	else
		acpi_thermal_get_polling_frequency(tz);

	/* Get devices in this thermal zone [_TZD] (optional) */
	result = acpi_thermal_get_devices(tz);
	if (!result)
		tz->flags.devices = 1;

	return_VALUE(0);
}

static int acpi_thermal_add(struct acpi_device *device)
{
	int result = 0;
	acpi_status status = AE_OK;
	struct acpi_thermal *tz = NULL;

	ACPI_FUNCTION_TRACE("acpi_thermal_add");

	if (!device)
		return_VALUE(-EINVAL);

	tz = kmalloc(sizeof(struct acpi_thermal), GFP_KERNEL);
	if (!tz)
		return_VALUE(-ENOMEM);
	memset(tz, 0, sizeof(struct acpi_thermal));

	tz->handle = device->handle;
	strcpy(tz->name, device->pnp.bus_id);
	strcpy(acpi_device_name(device), ACPI_THERMAL_DEVICE_NAME);
	strcpy(acpi_device_class(device), ACPI_THERMAL_CLASS);
	acpi_driver_data(device) = tz;

	result = acpi_thermal_get_info(tz);
	if (result)
		goto end;

	result = acpi_thermal_add_fs(device);
	if (result)
		return_VALUE(result);

	init_timer(&tz->timer);

	acpi_thermal_check(tz);

	status = acpi_install_notify_handler(tz->handle,
					     ACPI_DEVICE_NOTIFY,
					     acpi_thermal_notify, tz);
	if (ACPI_FAILURE(status)) {
		ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
				  "Error installing notify handler\n"));
		result = -ENODEV;
		goto end;
	}

	printk(KERN_INFO PREFIX "%s [%s] (%ld C)\n",
	       acpi_device_name(device), acpi_device_bid(device),
	       KELVIN_TO_CELSIUS(tz->temperature));

      end:
	if (result) {
		acpi_thermal_remove_fs(device);
		kfree(tz);
	}

	return_VALUE(result);
}

static int acpi_thermal_remove(struct acpi_device *device, int type)
{
	acpi_status status = AE_OK;
	struct acpi_thermal *tz = NULL;

	ACPI_FUNCTION_TRACE("acpi_thermal_remove");

	if (!device || !acpi_driver_data(device))
		return_VALUE(-EINVAL);

	tz = (struct acpi_thermal *)acpi_driver_data(device);

	/* avoid timer adding new defer task */
	tz->zombie = 1;
	/* wait for running timer (on other CPUs) finish */
	del_timer_sync(&(tz->timer));
	/* synchronize deferred task */
	acpi_os_wait_events_complete(NULL);
	/* deferred task may reinsert timer */
	del_timer_sync(&(tz->timer));

	status = acpi_remove_notify_handler(tz->handle,
					    ACPI_DEVICE_NOTIFY,
					    acpi_thermal_notify);
	if (ACPI_FAILURE(status))
		ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
				  "Error removing notify handler\n"));

	/* Terminate policy */
	if (tz->trips.passive.flags.valid && tz->trips.passive.flags.enabled) {
		tz->trips.passive.flags.enabled = 0;
		acpi_thermal_passive(tz);
	}
	if (tz->trips.active[0].flags.valid
	    && tz->trips.active[0].flags.enabled) {
		tz->trips.active[0].flags.enabled = 0;
		acpi_thermal_active(tz);
	}

	acpi_thermal_remove_fs(device);

	kfree(tz);
	return_VALUE(0);
}

static int acpi_thermal_resume(struct acpi_device *device, int state)
{
	struct acpi_thermal *tz = NULL;

	if (!device || !acpi_driver_data(device))
		return_VALUE(-EINVAL);

	tz = (struct acpi_thermal *)acpi_driver_data(device);

	acpi_thermal_check(tz);

	return AE_OK;
}

static int __init acpi_thermal_init(void)
{
	int result = 0;

	ACPI_FUNCTION_TRACE("acpi_thermal_init");

	acpi_thermal_dir = proc_mkdir(ACPI_THERMAL_CLASS, acpi_root_dir);
	if (!acpi_thermal_dir)
		return_VALUE(-ENODEV);
	acpi_thermal_dir->owner = THIS_MODULE;

	result = acpi_bus_register_driver(&acpi_thermal_driver);
	if (result < 0) {
		remove_proc_entry(ACPI_THERMAL_CLASS, acpi_root_dir);
		return_VALUE(-ENODEV);
	}

	return_VALUE(0);
}

static void __exit acpi_thermal_exit(void)
{
	ACPI_FUNCTION_TRACE("acpi_thermal_exit");

	acpi_bus_unregister_driver(&acpi_thermal_driver);

	remove_proc_entry(ACPI_THERMAL_CLASS, acpi_root_dir);

	return_VOID;
}

module_init(acpi_thermal_init);
module_exit(acpi_thermal_exit);