178afa1fd56c0ad899ec4a255cdf01fe2db2f114
[sfrench/cifs-2.6.git] / 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
7  * http://www.analog.com/UploadedFiles/Data_Sheets/115254175ADT7467_pra.pdf
8  * http://www.analog.com/UploadedFiles/Data_Sheets/3686221171167ADT7460_b.pdf
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/smp_lock.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
29 #include <asm/prom.h>
30 #include <asm/machdep.h>
31 #include <asm/io.h>
32 #include <asm/system.h>
33 #include <asm/sections.h>
34 #include <asm/of_platform.h>
35
36 #undef DEBUG
37
38 #define CONFIG_REG   0x40
39 #define MANUAL_MASK  0xe0
40 #define AUTO_MASK    0x20
41
42 static u8 TEMP_REG[3]    = {0x26, 0x25, 0x27}; /* local, sensor1, sensor2 */
43 static u8 LIMIT_REG[3]   = {0x6b, 0x6a, 0x6c}; /* local, sensor1, sensor2 */
44 static u8 MANUAL_MODE[2] = {0x5c, 0x5d};       
45 static u8 REM_CONTROL[2] = {0x00, 0x40};
46 static u8 FAN_SPEED[2]   = {0x28, 0x2a};
47 static u8 FAN_SPD_SET[2] = {0x30, 0x31};
48
49 static u8 default_limits_local[3] = {70, 50, 70};    /* local, sensor1, sensor2 */
50 static u8 default_limits_chip[3] = {80, 65, 80};    /* local, sensor1, sensor2 */
51 static const char *sensor_location[3];
52
53 static int limit_adjust;
54 static int fan_speed = -1;
55 static int verbose;
56
57 MODULE_AUTHOR("Colin Leroy <colin@colino.net>");
58 MODULE_DESCRIPTION("Driver for ADT746x thermostat in iBook G4 and "
59                    "Powerbook G4 Alu");
60 MODULE_LICENSE("GPL");
61
62 module_param(limit_adjust, int, 0644);
63 MODULE_PARM_DESC(limit_adjust,"Adjust maximum temperatures (50 sensor1, 70 sensor2) "
64                  "by N degrees.");
65
66 module_param(fan_speed, int, 0644);
67 MODULE_PARM_DESC(fan_speed,"Specify starting fan speed (0-255) "
68                  "(default 64)");
69
70 module_param(verbose, bool, 0);
71 MODULE_PARM_DESC(verbose,"Verbose log operations "
72                  "(default 0)");
73
74 struct 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 };
83
84 static enum {ADT7460, ADT7467} therm_type;
85 static int therm_bus, therm_address;
86 static struct of_device * of_dev;
87 static struct thermostat* thermostat;
88 static struct task_struct *thread_therm = NULL;
89
90 static int attach_one_thermostat(struct i2c_adapter *adapter, int addr,
91                                  int busno);
92
93 static void write_both_fan_speed(struct thermostat *th, int speed);
94 static void write_fan_speed(struct thermostat *th, int speed, int fan);
95
96 static int
97 write_reg(struct thermostat* th, int reg, u8 data)
98 {
99         u8 tmp[2];
100         int rc;
101         
102         tmp[0] = reg;
103         tmp[1] = data;
104         rc = i2c_master_send(&th->clt, (const char *)tmp, 2);
105         if (rc < 0)
106                 return rc;
107         if (rc != 2)
108                 return -ENODEV;
109         return 0;
110 }
111
112 static int
113 read_reg(struct thermostat* th, int reg)
114 {
115         u8 reg_addr, data;
116         int rc;
117
118         reg_addr = (u8)reg;
119         rc = i2c_master_send(&th->clt, &reg_addr, 1);
120         if (rc < 0)
121                 return rc;
122         if (rc != 1)
123                 return -ENODEV;
124         rc = i2c_master_recv(&th->clt, (char *)&data, 1);
125         if (rc < 0)
126                 return rc;
127         return data;
128 }
129
130 static int
131 attach_thermostat(struct i2c_adapter *adapter)
132 {
133         unsigned long bus_no;
134
135         if (strncmp(adapter->name, "uni-n", 5))
136                 return -ENODEV;
137         bus_no = simple_strtoul(adapter->name + 6, NULL, 10);
138         if (bus_no != therm_bus)
139                 return -ENODEV;
140         return attach_one_thermostat(adapter, therm_address, bus_no);
141 }
142
143 static int
144 detach_thermostat(struct i2c_adapter *adapter)
145 {
146         struct thermostat* th;
147         int i;
148         
149         if (thermostat == NULL)
150                 return 0;
151
152         th = thermostat;
153
154         if (thread_therm != NULL) {
155                 kthread_stop(thread_therm);
156         }
157
158         printk(KERN_INFO "adt746x: Putting max temperatures back from "
159                          "%d, %d, %d to %d, %d, %d\n",
160                 th->limits[0], th->limits[1], th->limits[2],
161                 th->initial_limits[0], th->initial_limits[1],
162                 th->initial_limits[2]);
163
164         for (i = 0; i < 3; i++)
165                 write_reg(th, LIMIT_REG[i], th->initial_limits[i]);
166
167         write_both_fan_speed(th, -1);
168
169         i2c_detach_client(&th->clt);
170
171         thermostat = NULL;
172
173         kfree(th);
174
175         return 0;
176 }
177
178 static struct i2c_driver thermostat_driver = {  
179         .driver = {
180                 .name   = "therm_adt746x",
181         },
182         .attach_adapter = attach_thermostat,
183         .detach_adapter = detach_thermostat,
184 };
185
186 static int read_fan_speed(struct thermostat *th, u8 addr)
187 {
188         u8 tmp[2];
189         u16 res;
190         
191         /* should start with low byte */
192         tmp[1] = read_reg(th, addr);
193         tmp[0] = read_reg(th, addr + 1);
194         
195         res = tmp[1] + (tmp[0] << 8);
196         /* "a value of 0xffff means that the fan has stopped" */
197         return (res == 0xffff ? 0 : (90000*60)/res);
198 }
199
200 static void write_both_fan_speed(struct thermostat *th, int speed)
201 {
202         write_fan_speed(th, speed, 0);
203         if (therm_type == ADT7460)
204                 write_fan_speed(th, speed, 1);
205 }
206
207 static void write_fan_speed(struct thermostat *th, int speed, int fan)
208 {
209         u8 manual;
210         
211         if (speed > 0xff) 
212                 speed = 0xff;
213         else if (speed < -1) 
214                 speed = 0;
215         
216         if (therm_type == ADT7467 && fan == 1)
217                 return;
218         
219         if (th->last_speed[fan] != speed) {
220                 if (verbose) {
221                         if (speed == -1)
222                                 printk(KERN_DEBUG "adt746x: Setting speed to automatic "
223                                         "for %s fan.\n", sensor_location[fan+1]);
224                         else
225                                 printk(KERN_DEBUG "adt746x: Setting speed to %d "
226                                         "for %s fan.\n", speed, sensor_location[fan+1]);
227                 }
228         } else
229                 return;
230         
231         if (speed >= 0) {
232                 manual = read_reg(th, MANUAL_MODE[fan]);
233                 write_reg(th, MANUAL_MODE[fan], manual|MANUAL_MASK);
234                 write_reg(th, FAN_SPD_SET[fan], speed);
235         } else {
236                 /* back to automatic */
237                 if(therm_type == ADT7460) {
238                         manual = read_reg(th,
239                                 MANUAL_MODE[fan]) & (~MANUAL_MASK);
240
241                         write_reg(th,
242                                 MANUAL_MODE[fan], manual|REM_CONTROL[fan]);
243                 } else {
244                         manual = read_reg(th, MANUAL_MODE[fan]);
245                         write_reg(th, MANUAL_MODE[fan], manual&(~AUTO_MASK));
246                 }
247         }
248         
249         th->last_speed[fan] = speed;                    
250 }
251
252 static void read_sensors(struct thermostat *th)
253 {
254         int i = 0;
255
256         for (i = 0; i < 3; i++)
257                 th->temps[i]  = read_reg(th, TEMP_REG[i]);
258 }
259
260 #ifdef DEBUG
261 static void display_stats(struct thermostat *th)
262 {
263         if (th->temps[0] != th->cached_temp[0]
264         ||  th->temps[1] != th->cached_temp[1]
265         ||  th->temps[2] != th->cached_temp[2]) {
266                 printk(KERN_INFO "adt746x: Temperature infos:"
267                                  " thermostats: %d,%d,%d;"
268                                  " limits: %d,%d,%d;"
269                                  " fan speed: %d RPM\n",
270                                  th->temps[0], th->temps[1], th->temps[2],
271                                  th->limits[0],  th->limits[1],  th->limits[2],
272                                  read_fan_speed(th, FAN_SPEED[0]));
273         }
274         th->cached_temp[0] = th->temps[0];
275         th->cached_temp[1] = th->temps[1];
276         th->cached_temp[2] = th->temps[2];
277 }
278 #endif
279
280 static void update_fans_speed (struct thermostat *th)
281 {
282         int lastvar = 0; /* last variation, for iBook */
283         int i = 0;
284
285         /* we don't care about local sensor, so we start at sensor 1 */
286         for (i = 1; i < 3; i++) {
287                 int started = 0;
288                 int fan_number = (therm_type == ADT7460 && i == 2);
289                 int var = th->temps[i] - th->limits[i];
290
291                 if (var > -1) {
292                         int step = (255 - fan_speed) / 7;
293                         int new_speed = 0;
294
295                         /* hysteresis : change fan speed only if variation is
296                          * more than two degrees */
297                         if (abs(var - th->last_var[fan_number]) < 2)
298                                 continue;
299
300                         started = 1;
301                         new_speed = fan_speed + ((var-1)*step);
302
303                         if (new_speed < fan_speed)
304                                 new_speed = fan_speed;
305                         if (new_speed > 255)
306                                 new_speed = 255;
307
308                         if (verbose)
309                                 printk(KERN_DEBUG "adt746x: Setting fans speed to %d "
310                                                  "(limit exceeded by %d on %s) \n",
311                                                 new_speed, var,
312                                                 sensor_location[fan_number+1]);
313                         write_both_fan_speed(th, new_speed);
314                         th->last_var[fan_number] = var;
315                 } else if (var < -2) {
316                         /* don't stop fan if sensor2 is cold and sensor1 is not
317                          * so cold (lastvar >= -1) */
318                         if (i == 2 && lastvar < -1) {
319                                 if (th->last_speed[fan_number] != 0)
320                                         if (verbose)
321                                                 printk(KERN_DEBUG "adt746x: Stopping "
322                                                         "fans.\n");
323                                 write_both_fan_speed(th, 0);
324                         }
325                 }
326
327                 lastvar = var;
328
329                 if (started)
330                         return; /* we don't want to re-stop the fan
331                                 * if sensor1 is heating and sensor2 is not */
332         }
333 }
334
335 static int monitor_task(void *arg)
336 {
337         struct thermostat* th = arg;
338
339         while(!kthread_should_stop()) {
340                 try_to_freeze();
341                 msleep_interruptible(2000);
342
343 #ifndef DEBUG
344                 if (fan_speed != -1)
345                         read_sensors(th);
346 #else
347                 read_sensors(th);
348 #endif          
349
350                 if (fan_speed != -1)
351                         update_fans_speed(th);
352
353 #ifdef DEBUG
354                 display_stats(th);
355 #endif
356
357         }
358
359         return 0;
360 }
361
362 static void set_limit(struct thermostat *th, int i)
363 {
364                 /* Set sensor1 limit higher to avoid powerdowns */
365                 th->limits[i] = default_limits_chip[i] + limit_adjust;
366                 write_reg(th, LIMIT_REG[i], th->limits[i]);
367                 
368                 /* set our limits to normal */
369                 th->limits[i] = default_limits_local[i] + limit_adjust;
370 }
371
372 static int attach_one_thermostat(struct i2c_adapter *adapter, int addr,
373                                  int busno)
374 {
375         struct thermostat* th;
376         int rc;
377         int i;
378
379         if (thermostat)
380                 return 0;
381
382         th = (struct thermostat *)
383                 kmalloc(sizeof(struct thermostat), GFP_KERNEL);
384
385         if (!th)
386                 return -ENOMEM;
387
388         memset(th, 0, sizeof(*th));
389         th->clt.addr = addr;
390         th->clt.adapter = adapter;
391         th->clt.driver = &thermostat_driver;
392         strcpy(th->clt.name, "thermostat");
393
394         rc = read_reg(th, 0);
395         if (rc < 0) {
396                 printk(KERN_ERR "adt746x: Thermostat failed to read config "
397                                 "from bus %d !\n",
398                                 busno);
399                 kfree(th);
400                 return -ENODEV;
401         }
402
403         /* force manual control to start the fan quieter */
404         if (fan_speed == -1)
405                 fan_speed = 64;
406         
407         if(therm_type == ADT7460) {
408                 printk(KERN_INFO "adt746x: ADT7460 initializing\n");
409                 /* The 7460 needs to be started explicitly */
410                 write_reg(th, CONFIG_REG, 1);
411         } else
412                 printk(KERN_INFO "adt746x: ADT7467 initializing\n");
413
414         for (i = 0; i < 3; i++) {
415                 th->initial_limits[i] = read_reg(th, LIMIT_REG[i]);
416                 set_limit(th, i);
417         }
418
419         printk(KERN_INFO "adt746x: Lowering max temperatures from %d, %d, %d"
420                          " to %d, %d, %d\n",
421                          th->initial_limits[0], th->initial_limits[1],
422                          th->initial_limits[2], th->limits[0], th->limits[1],
423                          th->limits[2]);
424
425         thermostat = th;
426
427         if (i2c_attach_client(&th->clt)) {
428                 printk(KERN_INFO "adt746x: Thermostat failed to attach "
429                                  "client !\n");
430                 thermostat = NULL;
431                 kfree(th);
432                 return -ENODEV;
433         }
434
435         /* be sure to really write fan speed the first time */
436         th->last_speed[0] = -2;
437         th->last_speed[1] = -2;
438         th->last_var[0] = -80;
439         th->last_var[1] = -80;
440
441         if (fan_speed != -1) {
442                 /* manual mode, stop fans */
443                 write_both_fan_speed(th, 0);
444         } else {
445                 /* automatic mode */
446                 write_both_fan_speed(th, -1);
447         }
448         
449         thread_therm = kthread_run(monitor_task, th, "kfand");
450
451         if (thread_therm == ERR_PTR(-ENOMEM)) {
452                 printk(KERN_INFO "adt746x: Kthread creation failed\n");
453                 thread_therm = NULL;
454                 return -ENOMEM;
455         }
456
457         return 0;
458 }
459
460 /* 
461  * Now, unfortunately, sysfs doesn't give us a nice void * we could
462  * pass around to the attribute functions, so we don't really have
463  * choice but implement a bunch of them...
464  *
465  * FIXME, it does now...
466  */
467 #define BUILD_SHOW_FUNC_INT(name, data)                         \
468 static ssize_t show_##name(struct device *dev, struct device_attribute *attr, char *buf)        \
469 {                                                               \
470         return sprintf(buf, "%d\n", data);                      \
471 }
472
473 #define BUILD_SHOW_FUNC_STR(name, data)                         \
474 static ssize_t show_##name(struct device *dev, struct device_attribute *attr, char *buf)       \
475 {                                                               \
476         return sprintf(buf, "%s\n", data);                      \
477 }
478
479 #define BUILD_SHOW_FUNC_FAN(name, data)                         \
480 static ssize_t show_##name(struct device *dev, struct device_attribute *attr, char *buf)       \
481 {                                                               \
482         return sprintf(buf, "%d (%d rpm)\n",                    \
483                 thermostat->last_speed[data],                   \
484                 read_fan_speed(thermostat, FAN_SPEED[data])     \
485                 );                                              \
486 }
487
488 #define BUILD_STORE_FUNC_DEG(name, data)                        \
489 static ssize_t store_##name(struct device *dev, struct device_attribute *attr, const char *buf, size_t n) \
490 {                                                               \
491         int val;                                                \
492         int i;                                                  \
493         val = simple_strtol(buf, NULL, 10);                     \
494         printk(KERN_INFO "Adjusting limits by %d degrees\n", val);      \
495         limit_adjust = val;                                     \
496         for (i=0; i < 3; i++)                                   \
497                 set_limit(thermostat, i);                       \
498         return n;                                               \
499 }
500
501 #define BUILD_STORE_FUNC_INT(name, data)                        \
502 static ssize_t store_##name(struct device *dev, struct device_attribute *attr, const char *buf, size_t n) \
503 {                                                               \
504         u32 val;                                                \
505         val = simple_strtoul(buf, NULL, 10);                    \
506         if (val < 0 || val > 255)                               \
507                 return -EINVAL;                                 \
508         printk(KERN_INFO "Setting specified fan speed to %d\n", val);   \
509         data = val;                                             \
510         return n;                                               \
511 }
512
513 BUILD_SHOW_FUNC_INT(sensor1_temperature,         (read_reg(thermostat, TEMP_REG[1])))
514 BUILD_SHOW_FUNC_INT(sensor2_temperature,         (read_reg(thermostat, TEMP_REG[2])))
515 BUILD_SHOW_FUNC_INT(sensor1_limit,               thermostat->limits[1])
516 BUILD_SHOW_FUNC_INT(sensor2_limit,               thermostat->limits[2])
517 BUILD_SHOW_FUNC_STR(sensor1_location,            sensor_location[1])
518 BUILD_SHOW_FUNC_STR(sensor2_location,            sensor_location[2])
519
520 BUILD_SHOW_FUNC_INT(specified_fan_speed, fan_speed)
521 BUILD_SHOW_FUNC_FAN(sensor1_fan_speed,   0)
522 BUILD_SHOW_FUNC_FAN(sensor2_fan_speed,   1)
523
524 BUILD_STORE_FUNC_INT(specified_fan_speed,fan_speed)
525 BUILD_SHOW_FUNC_INT(limit_adjust,        limit_adjust)
526 BUILD_STORE_FUNC_DEG(limit_adjust,       thermostat)
527                 
528 static DEVICE_ATTR(sensor1_temperature, S_IRUGO,
529                    show_sensor1_temperature,NULL);
530 static DEVICE_ATTR(sensor2_temperature, S_IRUGO,
531                    show_sensor2_temperature,NULL);
532 static DEVICE_ATTR(sensor1_limit, S_IRUGO,
533                    show_sensor1_limit,  NULL);
534 static DEVICE_ATTR(sensor2_limit, S_IRUGO,
535                    show_sensor2_limit,  NULL);
536 static DEVICE_ATTR(sensor1_location, S_IRUGO,
537                    show_sensor1_location, NULL);
538 static DEVICE_ATTR(sensor2_location, S_IRUGO,
539                    show_sensor2_location, NULL);
540
541 static DEVICE_ATTR(specified_fan_speed, S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH,
542                    show_specified_fan_speed,store_specified_fan_speed);
543
544 static DEVICE_ATTR(sensor1_fan_speed,   S_IRUGO,
545                    show_sensor1_fan_speed,      NULL);
546 static DEVICE_ATTR(sensor2_fan_speed,   S_IRUGO,
547                    show_sensor2_fan_speed,      NULL);
548
549 static DEVICE_ATTR(limit_adjust,        S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH,
550                    show_limit_adjust,   store_limit_adjust);
551
552
553 static int __init
554 thermostat_init(void)
555 {
556         struct device_node* np;
557         const u32 *prop;
558         int i = 0, offset = 0;
559         
560         np = of_find_node_by_name(NULL, "fan");
561         if (!np)
562                 return -ENODEV;
563         if (of_device_is_compatible(np, "adt7460"))
564                 therm_type = ADT7460;
565         else if (of_device_is_compatible(np, "adt7467"))
566                 therm_type = ADT7467;
567         else
568                 return -ENODEV;
569
570         prop = of_get_property(np, "hwsensor-params-version", NULL);
571         printk(KERN_INFO "adt746x: version %d (%ssupported)\n", *prop,
572                          (*prop == 1)?"":"un");
573         if (*prop != 1)
574                 return -ENODEV;
575
576         prop = of_get_property(np, "reg", NULL);
577         if (!prop)
578                 return -ENODEV;
579
580         /* look for bus either by path or using "reg" */
581         if (strstr(np->full_name, "/i2c-bus@") != NULL) {
582                 const char *tmp_bus = (strstr(np->full_name, "/i2c-bus@") + 9);
583                 therm_bus = tmp_bus[0]-'0';
584         } else {
585                 therm_bus = ((*prop) >> 8) & 0x0f;
586         }
587
588         therm_address = ((*prop) & 0xff) >> 1;
589
590         printk(KERN_INFO "adt746x: Thermostat bus: %d, address: 0x%02x, "
591                          "limit_adjust: %d, fan_speed: %d\n",
592                          therm_bus, therm_address, limit_adjust, fan_speed);
593
594         if (of_get_property(np, "hwsensor-location", NULL)) {
595                 for (i = 0; i < 3; i++) {
596                         sensor_location[i] = of_get_property(np,
597                                         "hwsensor-location", NULL) + offset;
598
599                         if (sensor_location[i] == NULL)
600                                 sensor_location[i] = "";
601
602                         printk(KERN_INFO "sensor %d: %s\n", i, sensor_location[i]);
603                         offset += strlen(sensor_location[i]) + 1;
604                 }
605         } else {
606                 sensor_location[0] = "?";
607                 sensor_location[1] = "?";
608                 sensor_location[2] = "?";
609         }
610
611         of_dev = of_platform_device_create(np, "temperatures", NULL);
612         
613         if (of_dev == NULL) {
614                 printk(KERN_ERR "Can't register temperatures device !\n");
615                 return -ENODEV;
616         }
617         
618         device_create_file(&of_dev->dev, &dev_attr_sensor1_temperature);
619         device_create_file(&of_dev->dev, &dev_attr_sensor2_temperature);
620         device_create_file(&of_dev->dev, &dev_attr_sensor1_limit);
621         device_create_file(&of_dev->dev, &dev_attr_sensor2_limit);
622         device_create_file(&of_dev->dev, &dev_attr_sensor1_location);
623         device_create_file(&of_dev->dev, &dev_attr_sensor2_location);
624         device_create_file(&of_dev->dev, &dev_attr_limit_adjust);
625         device_create_file(&of_dev->dev, &dev_attr_specified_fan_speed);
626         device_create_file(&of_dev->dev, &dev_attr_sensor1_fan_speed);
627         if(therm_type == ADT7460)
628                 device_create_file(&of_dev->dev, &dev_attr_sensor2_fan_speed);
629
630 #ifndef CONFIG_I2C_POWERMAC
631         request_module("i2c-powermac");
632 #endif
633
634         return i2c_add_driver(&thermostat_driver);
635 }
636
637 static void __exit
638 thermostat_exit(void)
639 {
640         if (of_dev) {
641                 device_remove_file(&of_dev->dev, &dev_attr_sensor1_temperature);
642                 device_remove_file(&of_dev->dev, &dev_attr_sensor2_temperature);
643                 device_remove_file(&of_dev->dev, &dev_attr_sensor1_limit);
644                 device_remove_file(&of_dev->dev, &dev_attr_sensor2_limit);
645                 device_remove_file(&of_dev->dev, &dev_attr_sensor1_location);
646                 device_remove_file(&of_dev->dev, &dev_attr_sensor2_location);
647                 device_remove_file(&of_dev->dev, &dev_attr_limit_adjust);
648                 device_remove_file(&of_dev->dev, &dev_attr_specified_fan_speed);
649                 device_remove_file(&of_dev->dev, &dev_attr_sensor1_fan_speed);
650
651                 if(therm_type == ADT7460)
652                         device_remove_file(&of_dev->dev,
653                                            &dev_attr_sensor2_fan_speed);
654
655                 of_device_unregister(of_dev);
656         }
657         i2c_del_driver(&thermostat_driver);
658 }
659
660 module_init(thermostat_init);
661 module_exit(thermostat_exit);