linux/drivers/macintosh/therm_adt746x.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Device driver for the i2c thermostat found on the iBook G4, Albook G4
   4 *
   5 * Copyright (C) 2003, 2004 Colin Leroy, Rasmus Rohde, Benjamin Herrenschmidt
   6 *
   7 * Documentation from 115254175ADT7467_pra.pdf and 3686221171167ADT7460_b.pdf
   8 * https://www.onsemi.com/PowerSolutions/product.do?id=ADT7467
   9 * https://www.onsemi.com/PowerSolutions/product.do?id=ADT7460
  10 *
  11 */
  12
  13#include <linux/types.h>
  14#include <linux/module.h>
  15#include <linux/errno.h>
  16#include <linux/kernel.h>
  17#include <linux/delay.h>
  18#include <linux/sched.h>
  19#include <linux/i2c.h>
  20#include <linux/slab.h>
  21#include <linux/init.h>
  22#include <linux/spinlock.h>
  23#include <linux/wait.h>
  24#include <linux/suspend.h>
  25#include <linux/kthread.h>
  26#include <linux/moduleparam.h>
  27#include <linux/freezer.h>
  28#include <linux/of_platform.h>
  29
  30#include <asm/prom.h>
  31#include <asm/machdep.h>
  32#include <asm/io.h>
  33#include <asm/sections.h>
  34
  35#undef DEBUG
  36
  37#define CONFIG_REG   0x40
  38#define MANUAL_MASK  0xe0
  39#define AUTO_MASK    0x20
  40#define INVERT_MASK  0x10
  41
  42static u8 TEMP_REG[3]    = {0x26, 0x25, 0x27}; /* local, sensor1, sensor2 */
  43static u8 LIMIT_REG[3]   = {0x6b, 0x6a, 0x6c}; /* local, sensor1, sensor2 */
  44static u8 MANUAL_MODE[2] = {0x5c, 0x5d};       
  45static u8 REM_CONTROL[2] = {0x00, 0x40};
  46static u8 FAN_SPEED[2]   = {0x28, 0x2a};
  47static u8 FAN_SPD_SET[2] = {0x30, 0x31};
  48
  49static u8 default_limits_local[3] = {70, 50, 70};    /* local, sensor1, sensor2 */
  50static u8 default_limits_chip[3] = {80, 65, 80};    /* local, sensor1, sensor2 */
  51static const char *sensor_location[3] = { "?", "?", "?" };
  52
  53static int limit_adjust;
  54static int fan_speed = -1;
  55static bool verbose;
  56
  57MODULE_AUTHOR("Colin Leroy <colin@colino.net>");
  58MODULE_DESCRIPTION("Driver for ADT746x thermostat in iBook G4 and "
  59                   "Powerbook G4 Alu");
  60MODULE_LICENSE("GPL");
  61
  62module_param(limit_adjust, int, 0644);
  63MODULE_PARM_DESC(limit_adjust,"Adjust maximum temperatures (50 sensor1, 70 sensor2) "
  64                 "by N degrees.");
  65
  66module_param(fan_speed, int, 0644);
  67MODULE_PARM_DESC(fan_speed,"Specify starting fan speed (0-255) "
  68                 "(default 64)");
  69
  70module_param(verbose, bool, 0);
  71MODULE_PARM_DESC(verbose,"Verbose log operations "
  72                 "(default 0)");
  73
  74struct thermostat {
  75        struct i2c_client       *clt;
  76        u8                      temps[3];
  77        u8                      cached_temp[3];
  78        u8                      initial_limits[3];
  79        u8                      limits[3];
  80        int                     last_speed[2];
  81        int                     last_var[2];
  82        int                     pwm_inv[2];
  83        struct task_struct      *thread;
  84        struct platform_device  *pdev;
  85        enum {
  86                ADT7460,
  87                ADT7467
  88        }                       type;
  89};
  90
  91static void write_both_fan_speed(struct thermostat *th, int speed);
  92static void write_fan_speed(struct thermostat *th, int speed, int fan);
  93
  94static int
  95write_reg(struct thermostat* th, int reg, u8 data)
  96{
  97        u8 tmp[2];
  98        int rc;
  99        
 100        tmp[0] = reg;
 101        tmp[1] = data;
 102        rc = i2c_master_send(th->clt, (const char *)tmp, 2);
 103        if (rc < 0)
 104                return rc;
 105        if (rc != 2)
 106                return -ENODEV;
 107        return 0;
 108}
 109
 110static int
 111read_reg(struct thermostat* th, int reg)
 112{
 113        u8 reg_addr, data;
 114        int rc;
 115
 116        reg_addr = (u8)reg;
 117        rc = i2c_master_send(th->clt, &reg_addr, 1);
 118        if (rc < 0)
 119                return rc;
 120        if (rc != 1)
 121                return -ENODEV;
 122        rc = i2c_master_recv(th->clt, (char *)&data, 1);
 123        if (rc < 0)
 124                return rc;
 125        return data;
 126}
 127
 128static int read_fan_speed(struct thermostat *th, u8 addr)
 129{
 130        u8 tmp[2];
 131        u16 res;
 132        
 133        /* should start with low byte */
 134        tmp[1] = read_reg(th, addr);
 135        tmp[0] = read_reg(th, addr + 1);
 136        
 137        res = tmp[1] + (tmp[0] << 8);
 138        /* "a value of 0xffff means that the fan has stopped" */
 139        return (res == 0xffff ? 0 : (90000*60)/res);
 140}
 141
 142static void write_both_fan_speed(struct thermostat *th, int speed)
 143{
 144        write_fan_speed(th, speed, 0);
 145        if (th->type == ADT7460)
 146                write_fan_speed(th, speed, 1);
 147}
 148
 149static void write_fan_speed(struct thermostat *th, int speed, int fan)
 150{
 151        u8 manual;
 152        
 153        if (speed > 0xff) 
 154                speed = 0xff;
 155        else if (speed < -1) 
 156                speed = 0;
 157        
 158        if (th->type == ADT7467 && fan == 1)
 159                return;
 160        
 161        if (th->last_speed[fan] != speed) {
 162                if (verbose) {
 163                        if (speed == -1)
 164                                printk(KERN_DEBUG "adt746x: Setting speed to automatic "
 165                                        "for %s fan.\n", sensor_location[fan+1]);
 166                        else
 167                                printk(KERN_DEBUG "adt746x: Setting speed to %d "
 168                                        "for %s fan.\n", speed, sensor_location[fan+1]);
 169                }
 170        } else
 171                return;
 172        
 173        if (speed >= 0) {
 174                manual = read_reg(th, MANUAL_MODE[fan]);
 175                manual &= ~INVERT_MASK;
 176                write_reg(th, MANUAL_MODE[fan],
 177                        manual | MANUAL_MASK | th->pwm_inv[fan]);
 178                write_reg(th, FAN_SPD_SET[fan], speed);
 179        } else {
 180                /* back to automatic */
 181                if(th->type == ADT7460) {
 182                        manual = read_reg(th,
 183                                MANUAL_MODE[fan]) & (~MANUAL_MASK);
 184                        manual &= ~INVERT_MASK;
 185                        manual |= th->pwm_inv[fan];
 186                        write_reg(th,
 187                                MANUAL_MODE[fan], manual|REM_CONTROL[fan]);
 188                } else {
 189                        manual = read_reg(th, MANUAL_MODE[fan]);
 190                        manual &= ~INVERT_MASK;
 191                        manual |= th->pwm_inv[fan];
 192                        write_reg(th, MANUAL_MODE[fan], manual&(~AUTO_MASK));
 193                }
 194        }
 195        
 196        th->last_speed[fan] = speed;                    
 197}
 198
 199static void read_sensors(struct thermostat *th)
 200{
 201        int i = 0;
 202
 203        for (i = 0; i < 3; i++)
 204                th->temps[i]  = read_reg(th, TEMP_REG[i]);
 205}
 206
 207#ifdef DEBUG
 208static void display_stats(struct thermostat *th)
 209{
 210        if (th->temps[0] != th->cached_temp[0]
 211        ||  th->temps[1] != th->cached_temp[1]
 212        ||  th->temps[2] != th->cached_temp[2]) {
 213                printk(KERN_INFO "adt746x: Temperature infos:"
 214                                 " thermostats: %d,%d,%d;"
 215                                 " limits: %d,%d,%d;"
 216                                 " fan speed: %d RPM\n",
 217                                 th->temps[0], th->temps[1], th->temps[2],
 218                                 th->limits[0],  th->limits[1],  th->limits[2],
 219                                 read_fan_speed(th, FAN_SPEED[0]));
 220        }
 221        th->cached_temp[0] = th->temps[0];
 222        th->cached_temp[1] = th->temps[1];
 223        th->cached_temp[2] = th->temps[2];
 224}
 225#endif
 226
 227static void update_fans_speed (struct thermostat *th)
 228{
 229        int lastvar = 0; /* last variation, for iBook */
 230        int i = 0;
 231
 232        /* we don't care about local sensor, so we start at sensor 1 */
 233        for (i = 1; i < 3; i++) {
 234                bool started = false;
 235                int fan_number = (th->type == ADT7460 && i == 2);
 236                int var = th->temps[i] - th->limits[i];
 237
 238                if (var > -1) {
 239                        int step = (255 - fan_speed) / 7;
 240                        int new_speed = 0;
 241
 242                        /* hysteresis : change fan speed only if variation is
 243                         * more than two degrees */
 244                        if (abs(var - th->last_var[fan_number]) < 2)
 245                                continue;
 246
 247                        started = true;
 248                        new_speed = fan_speed + ((var-1)*step);
 249
 250                        if (new_speed < fan_speed)
 251                                new_speed = fan_speed;
 252                        if (new_speed > 255)
 253                                new_speed = 255;
 254
 255                        if (verbose)
 256                                printk(KERN_DEBUG "adt746x: Setting fans speed to %d "
 257                                                 "(limit exceeded by %d on %s)\n",
 258                                                new_speed, var,
 259                                                sensor_location[fan_number+1]);
 260                        write_both_fan_speed(th, new_speed);
 261                        th->last_var[fan_number] = var;
 262                } else if (var < -2) {
 263                        /* don't stop fan if sensor2 is cold and sensor1 is not
 264                         * so cold (lastvar >= -1) */
 265                        if (i == 2 && lastvar < -1) {
 266                                if (th->last_speed[fan_number] != 0)
 267                                        if (verbose)
 268                                                printk(KERN_DEBUG "adt746x: Stopping "
 269                                                        "fans.\n");
 270                                write_both_fan_speed(th, 0);
 271                        }
 272                }
 273
 274                lastvar = var;
 275
 276                if (started)
 277                        return; /* we don't want to re-stop the fan
 278                                * if sensor1 is heating and sensor2 is not */
 279        }
 280}
 281
 282static int monitor_task(void *arg)
 283{
 284        struct thermostat* th = arg;
 285
 286        set_freezable();
 287        while(!kthread_should_stop()) {
 288                try_to_freeze();
 289                msleep_interruptible(2000);
 290
 291#ifndef DEBUG
 292                if (fan_speed != -1)
 293                        read_sensors(th);
 294#else
 295                read_sensors(th);
 296#endif          
 297
 298                if (fan_speed != -1)
 299                        update_fans_speed(th);
 300
 301#ifdef DEBUG
 302                display_stats(th);
 303#endif
 304
 305        }
 306
 307        return 0;
 308}
 309
 310static void set_limit(struct thermostat *th, int i)
 311{
 312        /* Set sensor1 limit higher to avoid powerdowns */
 313        th->limits[i] = default_limits_chip[i] + limit_adjust;
 314        write_reg(th, LIMIT_REG[i], th->limits[i]);
 315                
 316        /* set our limits to normal */
 317        th->limits[i] = default_limits_local[i] + limit_adjust;
 318}
 319
 320#define BUILD_SHOW_FUNC_INT(name, data)                         \
 321static ssize_t show_##name(struct device *dev, struct device_attribute *attr, char *buf)        \
 322{                                                               \
 323        struct thermostat *th = dev_get_drvdata(dev);           \
 324        return sprintf(buf, "%d\n", data);                      \
 325}
 326
 327#define BUILD_SHOW_FUNC_INT_LITE(name, data)                            \
 328static ssize_t show_##name(struct device *dev, struct device_attribute *attr, char *buf)        \
 329{                                                               \
 330        return sprintf(buf, "%d\n", data);                      \
 331}
 332
 333#define BUILD_SHOW_FUNC_STR(name, data)                         \
 334static ssize_t show_##name(struct device *dev, struct device_attribute *attr, char *buf)       \
 335{                                                               \
 336        return sprintf(buf, "%s\n", data);                      \
 337}
 338
 339#define BUILD_SHOW_FUNC_FAN(name, data)                         \
 340static ssize_t show_##name(struct device *dev, struct device_attribute *attr, char *buf)       \
 341{                                                               \
 342        struct thermostat *th = dev_get_drvdata(dev);           \
 343        return sprintf(buf, "%d (%d rpm)\n",                    \
 344                th->last_speed[data],                           \
 345                read_fan_speed(th, FAN_SPEED[data])             \
 346                );                                              \
 347}
 348
 349#define BUILD_STORE_FUNC_DEG(name, data)                        \
 350static ssize_t store_##name(struct device *dev, struct device_attribute *attr, const char *buf, size_t n) \
 351{                                                               \
 352        struct thermostat *th = dev_get_drvdata(dev);           \
 353        int val;                                                \
 354        int i;                                                  \
 355        val = simple_strtol(buf, NULL, 10);                     \
 356        printk(KERN_INFO "Adjusting limits by %d degrees\n", val);      \
 357        limit_adjust = val;                                     \
 358        for (i=0; i < 3; i++)                                   \
 359                set_limit(th, i);                               \
 360        return n;                                               \
 361}
 362
 363#define BUILD_STORE_FUNC_INT(name, data)                        \
 364static ssize_t store_##name(struct device *dev, struct device_attribute *attr, const char *buf, size_t n) \
 365{                                                               \
 366        int val;                                                \
 367        val = simple_strtol(buf, NULL, 10);                     \
 368        if (val < 0 || val > 255)                               \
 369                return -EINVAL;                                 \
 370        printk(KERN_INFO "Setting specified fan speed to %d\n", val);   \
 371        data = val;                                             \
 372        return n;                                               \
 373}
 374
 375BUILD_SHOW_FUNC_INT(sensor1_temperature,         (read_reg(th, TEMP_REG[1])))
 376BUILD_SHOW_FUNC_INT(sensor2_temperature,         (read_reg(th, TEMP_REG[2])))
 377BUILD_SHOW_FUNC_INT(sensor1_limit,               th->limits[1])
 378BUILD_SHOW_FUNC_INT(sensor2_limit,               th->limits[2])
 379BUILD_SHOW_FUNC_STR(sensor1_location,            sensor_location[1])
 380BUILD_SHOW_FUNC_STR(sensor2_location,            sensor_location[2])
 381
 382BUILD_SHOW_FUNC_INT_LITE(specified_fan_speed, fan_speed)
 383BUILD_STORE_FUNC_INT(specified_fan_speed,fan_speed)
 384
 385BUILD_SHOW_FUNC_FAN(sensor1_fan_speed,   0)
 386BUILD_SHOW_FUNC_FAN(sensor2_fan_speed,   1)
 387
 388BUILD_SHOW_FUNC_INT_LITE(limit_adjust,   limit_adjust)
 389BUILD_STORE_FUNC_DEG(limit_adjust,       th)
 390                
 391static DEVICE_ATTR(sensor1_temperature, S_IRUGO,
 392                   show_sensor1_temperature,NULL);
 393static DEVICE_ATTR(sensor2_temperature, S_IRUGO,
 394                   show_sensor2_temperature,NULL);
 395static DEVICE_ATTR(sensor1_limit, S_IRUGO,
 396                   show_sensor1_limit,  NULL);
 397static DEVICE_ATTR(sensor2_limit, S_IRUGO,
 398                   show_sensor2_limit,  NULL);
 399static DEVICE_ATTR(sensor1_location, S_IRUGO,
 400                   show_sensor1_location, NULL);
 401static DEVICE_ATTR(sensor2_location, S_IRUGO,
 402                   show_sensor2_location, NULL);
 403
 404static DEVICE_ATTR(specified_fan_speed, S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH,
 405                   show_specified_fan_speed,store_specified_fan_speed);
 406
 407static DEVICE_ATTR(sensor1_fan_speed,   S_IRUGO,
 408                   show_sensor1_fan_speed,      NULL);
 409static DEVICE_ATTR(sensor2_fan_speed,   S_IRUGO,
 410                   show_sensor2_fan_speed,      NULL);
 411
 412static DEVICE_ATTR(limit_adjust,        S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH,
 413                   show_limit_adjust,   store_limit_adjust);
 414
 415static void thermostat_create_files(struct thermostat *th)
 416{
 417        struct device_node *np = th->clt->dev.of_node;
 418        struct device *dev;
 419        int err;
 420
 421        /* To maintain ABI compatibility with userspace, create
 422         * the old style platform driver and attach the attributes
 423         * to it here
 424         */
 425        th->pdev = of_platform_device_create(np, "temperatures", NULL);
 426        if (!th->pdev)
 427                return;
 428        dev = &th->pdev->dev;
 429        dev_set_drvdata(dev, th);
 430        err = device_create_file(dev, &dev_attr_sensor1_temperature);
 431        err |= device_create_file(dev, &dev_attr_sensor2_temperature);
 432        err |= device_create_file(dev, &dev_attr_sensor1_limit);
 433        err |= device_create_file(dev, &dev_attr_sensor2_limit);
 434        err |= device_create_file(dev, &dev_attr_sensor1_location);
 435        err |= device_create_file(dev, &dev_attr_sensor2_location);
 436        err |= device_create_file(dev, &dev_attr_limit_adjust);
 437        err |= device_create_file(dev, &dev_attr_specified_fan_speed);
 438        err |= device_create_file(dev, &dev_attr_sensor1_fan_speed);
 439        if(th->type == ADT7460)
 440                err |= device_create_file(dev, &dev_attr_sensor2_fan_speed);
 441        if (err)
 442                printk(KERN_WARNING
 443                        "Failed to create temperature attribute file(s).\n");
 444}
 445
 446static void thermostat_remove_files(struct thermostat *th)
 447{
 448        struct device *dev;
 449
 450        if (!th->pdev)
 451                return;
 452        dev = &th->pdev->dev;
 453        device_remove_file(dev, &dev_attr_sensor1_temperature);
 454        device_remove_file(dev, &dev_attr_sensor2_temperature);
 455        device_remove_file(dev, &dev_attr_sensor1_limit);
 456        device_remove_file(dev, &dev_attr_sensor2_limit);
 457        device_remove_file(dev, &dev_attr_sensor1_location);
 458        device_remove_file(dev, &dev_attr_sensor2_location);
 459        device_remove_file(dev, &dev_attr_limit_adjust);
 460        device_remove_file(dev, &dev_attr_specified_fan_speed);
 461        device_remove_file(dev, &dev_attr_sensor1_fan_speed);   
 462        if (th->type == ADT7460)
 463                device_remove_file(dev, &dev_attr_sensor2_fan_speed);
 464        of_device_unregister(th->pdev);
 465
 466}
 467
 468static int probe_thermostat(struct i2c_client *client,
 469                            const struct i2c_device_id *id)
 470{
 471        struct device_node *np = client->dev.of_node;
 472        struct thermostat* th;
 473        const __be32 *prop;
 474        int i, rc, vers, offset = 0;
 475
 476        if (!np)
 477                return -ENXIO;
 478        prop = of_get_property(np, "hwsensor-params-version", NULL);
 479        if (!prop)
 480                return -ENXIO;
 481        vers = be32_to_cpup(prop);
 482        printk(KERN_INFO "adt746x: version %d (%ssupported)\n",
 483               vers, vers == 1 ? "" : "un");
 484        if (vers != 1)
 485                return -ENXIO;
 486
 487        if (of_get_property(np, "hwsensor-location", NULL)) {
 488                for (i = 0; i < 3; i++) {
 489                        sensor_location[i] = of_get_property(np,
 490                                        "hwsensor-location", NULL) + offset;
 491
 492                        if (sensor_location[i] == NULL)
 493                                sensor_location[i] = "";
 494
 495                        printk(KERN_INFO "sensor %d: %s\n", i, sensor_location[i]);
 496                        offset += strlen(sensor_location[i]) + 1;
 497                }
 498        }
 499
 500        th = kzalloc(sizeof(struct thermostat), GFP_KERNEL);
 501        if (!th)
 502                return -ENOMEM;
 503
 504        i2c_set_clientdata(client, th);
 505        th->clt = client;
 506        th->type = id->driver_data;
 507
 508        rc = read_reg(th, CONFIG_REG);
 509        if (rc < 0) {
 510                dev_err(&client->dev, "Thermostat failed to read config!\n");
 511                kfree(th);
 512                return -ENODEV;
 513        }
 514
 515        /* force manual control to start the fan quieter */
 516        if (fan_speed == -1)
 517                fan_speed = 64;
 518        
 519        if (th->type == ADT7460) {
 520                printk(KERN_INFO "adt746x: ADT7460 initializing\n");
 521                /* The 7460 needs to be started explicitly */
 522                write_reg(th, CONFIG_REG, 1);
 523        } else
 524                printk(KERN_INFO "adt746x: ADT7467 initializing\n");
 525
 526        for (i = 0; i < 3; i++) {
 527                th->initial_limits[i] = read_reg(th, LIMIT_REG[i]);
 528                set_limit(th, i);
 529        }
 530
 531        printk(KERN_INFO "adt746x: Lowering max temperatures from %d, %d, %d"
 532                         " to %d, %d, %d\n",
 533                         th->initial_limits[0], th->initial_limits[1],
 534                         th->initial_limits[2], th->limits[0], th->limits[1],
 535                         th->limits[2]);
 536
 537        /* record invert bit status because fw can corrupt it after suspend */
 538        th->pwm_inv[0] = read_reg(th, MANUAL_MODE[0]) & INVERT_MASK;
 539        th->pwm_inv[1] = read_reg(th, MANUAL_MODE[1]) & INVERT_MASK;
 540
 541        /* be sure to really write fan speed the first time */
 542        th->last_speed[0] = -2;
 543        th->last_speed[1] = -2;
 544        th->last_var[0] = -80;
 545        th->last_var[1] = -80;
 546
 547        if (fan_speed != -1) {
 548                /* manual mode, stop fans */
 549                write_both_fan_speed(th, 0);
 550        } else {
 551                /* automatic mode */
 552                write_both_fan_speed(th, -1);
 553        }
 554        
 555        th->thread = kthread_run(monitor_task, th, "kfand");
 556        if (th->thread == ERR_PTR(-ENOMEM)) {
 557                printk(KERN_INFO "adt746x: Kthread creation failed\n");
 558                th->thread = NULL;
 559                return -ENOMEM;
 560        }
 561
 562        thermostat_create_files(th);
 563
 564        return 0;
 565}
 566
 567static int remove_thermostat(struct i2c_client *client)
 568{
 569        struct thermostat *th = i2c_get_clientdata(client);
 570        int i;
 571        
 572        thermostat_remove_files(th);
 573
 574        if (th->thread != NULL)
 575                kthread_stop(th->thread);
 576
 577        printk(KERN_INFO "adt746x: Putting max temperatures back from "
 578                         "%d, %d, %d to %d, %d, %d\n",
 579                th->limits[0], th->limits[1], th->limits[2],
 580                th->initial_limits[0], th->initial_limits[1],
 581                th->initial_limits[2]);
 582
 583        for (i = 0; i < 3; i++)
 584                write_reg(th, LIMIT_REG[i], th->initial_limits[i]);
 585
 586        write_both_fan_speed(th, -1);
 587
 588        kfree(th);
 589
 590        return 0;
 591}
 592
 593static const struct i2c_device_id therm_adt746x_id[] = {
 594        { "MAC,adt7460", ADT7460 },
 595        { "MAC,adt7467", ADT7467 },
 596        { }
 597};
 598MODULE_DEVICE_TABLE(i2c, therm_adt746x_id);
 599
 600static struct i2c_driver thermostat_driver = {
 601        .driver = {
 602                .name   = "therm_adt746x",
 603        },
 604        .probe = probe_thermostat,
 605        .remove = remove_thermostat,
 606        .id_table = therm_adt746x_id,
 607};
 608
 609static int __init thermostat_init(void)
 610{
 611#ifndef CONFIG_I2C_POWERMAC
 612        request_module("i2c-powermac");
 613#endif
 614
 615        return i2c_add_driver(&thermostat_driver);
 616}
 617
 618static void __exit thermostat_exit(void)
 619{
 620        i2c_del_driver(&thermostat_driver);
 621}
 622
 623module_init(thermostat_init);
 624module_exit(thermostat_exit);
 625