drivers/macintosh/therm_adt746x.c

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