[PATCH] w1: cleanups.
[linux-2.6.git] / drivers / w1 / w1.c
1 /*
2  *      w1.c
3  *
4  * Copyright (c) 2004 Evgeniy Polyakov <johnpol@2ka.mipt.ru>
5  *
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License as published by
9  * the Free Software Foundation; either version 2 of the License, or
10  * (at your option) any later version.
11  *
12  * This program is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15  * GNU General Public License for more details.
16  *
17  * You should have received a copy of the GNU General Public License
18  * along with this program; if not, write to the Free Software
19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20  */
21
22 #include <linux/delay.h>
23 #include <linux/kernel.h>
24 #include <linux/module.h>
25 #include <linux/moduleparam.h>
26 #include <linux/list.h>
27 #include <linux/interrupt.h>
28 #include <linux/spinlock.h>
29 #include <linux/timer.h>
30 #include <linux/device.h>
31 #include <linux/slab.h>
32 #include <linux/sched.h>
33
34 #include <asm/atomic.h>
35
36 #include "w1.h"
37 #include "w1_io.h"
38 #include "w1_log.h"
39 #include "w1_int.h"
40 #include "w1_family.h"
41 #include "w1_netlink.h"
42
43 MODULE_LICENSE("GPL");
44 MODULE_AUTHOR("Evgeniy Polyakov <johnpol@2ka.mipt.ru>");
45 MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol.");
46
47 static int w1_timeout = 10;
48 int w1_max_slave_count = 10;
49 int w1_max_slave_ttl = 10;
50
51 module_param_named(timeout, w1_timeout, int, 0);
52 module_param_named(max_slave_count, w1_max_slave_count, int, 0);
53 module_param_named(slave_ttl, w1_max_slave_ttl, int, 0);
54
55 DEFINE_SPINLOCK(w1_mlock);
56 LIST_HEAD(w1_masters);
57
58 static pid_t control_thread;
59 static int control_needs_exit;
60 static DECLARE_COMPLETION(w1_control_complete);
61
62 static int w1_master_match(struct device *dev, struct device_driver *drv)
63 {
64         return 1;
65 }
66
67 static int w1_master_probe(struct device *dev)
68 {
69         return -ENODEV;
70 }
71
72 static int w1_master_remove(struct device *dev)
73 {
74         return 0;
75 }
76
77 static void w1_master_release(struct device *dev)
78 {
79         struct w1_master *md = container_of(dev, struct w1_master, dev);
80
81         complete(&md->dev_released);
82 }
83
84 static void w1_slave_release(struct device *dev)
85 {
86         struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
87
88         complete(&sl->dev_released);
89 }
90
91 static ssize_t w1_default_read_name(struct device *dev, struct device_attribute *attr, char *buf)
92 {
93         return sprintf(buf, "No family registered.\n");
94 }
95
96 static ssize_t w1_default_read_bin(struct kobject *kobj, char *buf, loff_t off,
97                      size_t count)
98 {
99         return sprintf(buf, "No family registered.\n");
100 }
101
102 static struct device_attribute w1_slave_attribute =
103         __ATTR(name, S_IRUGO, w1_default_read_name, NULL);
104
105 static struct device_attribute w1_slave_attribute_val =
106         __ATTR(value, S_IRUGO, w1_default_read_name, NULL);
107
108 static struct bin_attribute w1_slave_bin_attribute = {
109         .attr = {
110                 .name = "w1_slave",
111                 .mode = S_IRUGO,
112                 .owner = THIS_MODULE,
113         },
114         .size = W1_SLAVE_DATA_SIZE,
115         .read = &w1_default_read_bin,
116 };
117
118
119 static struct bus_type w1_bus_type = {
120         .name = "w1",
121         .match = w1_master_match,
122 };
123
124 struct device_driver w1_driver = {
125         .name = "w1_driver",
126         .bus = &w1_bus_type,
127         .probe = w1_master_probe,
128         .remove = w1_master_remove,
129 };
130
131 struct device w1_device = {
132         .parent = NULL,
133         .bus = &w1_bus_type,
134         .bus_id = "w1 bus master",
135         .driver = &w1_driver,
136         .release = &w1_master_release
137 };
138
139 static ssize_t w1_master_attribute_show_name(struct device *dev, struct device_attribute *attr, char *buf)
140 {
141         struct w1_master *md = container_of (dev, struct w1_master, dev);
142         ssize_t count;
143
144         if (down_interruptible (&md->mutex))
145                 return -EBUSY;
146
147         count = sprintf(buf, "%s\n", md->name);
148
149         up(&md->mutex);
150
151         return count;
152 }
153
154 static ssize_t w1_master_attribute_show_pointer(struct device *dev, struct device_attribute *attr, char *buf)
155 {
156         struct w1_master *md = container_of(dev, struct w1_master, dev);
157         ssize_t count;
158
159         if (down_interruptible(&md->mutex))
160                 return -EBUSY;
161
162         count = sprintf(buf, "0x%p\n", md->bus_master);
163
164         up(&md->mutex);
165         return count;
166 }
167
168 static ssize_t w1_master_attribute_show_timeout(struct device *dev, struct device_attribute *attr, char *buf)
169 {
170         ssize_t count;
171         count = sprintf(buf, "%d\n", w1_timeout);
172         return count;
173 }
174
175 static ssize_t w1_master_attribute_show_max_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
176 {
177         struct w1_master *md = container_of(dev, struct w1_master, dev);
178         ssize_t count;
179
180         if (down_interruptible(&md->mutex))
181                 return -EBUSY;
182
183         count = sprintf(buf, "%d\n", md->max_slave_count);
184
185         up(&md->mutex);
186         return count;
187 }
188
189 static ssize_t w1_master_attribute_show_attempts(struct device *dev, struct device_attribute *attr, char *buf)
190 {
191         struct w1_master *md = container_of(dev, struct w1_master, dev);
192         ssize_t count;
193
194         if (down_interruptible(&md->mutex))
195                 return -EBUSY;
196
197         count = sprintf(buf, "%lu\n", md->attempts);
198
199         up(&md->mutex);
200         return count;
201 }
202
203 static ssize_t w1_master_attribute_show_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
204 {
205         struct w1_master *md = container_of(dev, struct w1_master, dev);
206         ssize_t count;
207
208         if (down_interruptible(&md->mutex))
209                 return -EBUSY;
210
211         count = sprintf(buf, "%d\n", md->slave_count);
212
213         up(&md->mutex);
214         return count;
215 }
216
217 static ssize_t w1_master_attribute_show_slaves(struct device *dev, struct device_attribute *attr, char *buf)
218
219 {
220         struct w1_master *md = container_of(dev, struct w1_master, dev);
221         int c = PAGE_SIZE;
222
223         if (down_interruptible(&md->mutex))
224                 return -EBUSY;
225
226         if (md->slave_count == 0)
227                 c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n");
228         else {
229                 struct list_head *ent, *n;
230                 struct w1_slave *sl;
231
232                 list_for_each_safe(ent, n, &md->slist) {
233                         sl = list_entry(ent, struct w1_slave, w1_slave_entry);
234
235                         c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", sl->name);
236                 }
237         }
238
239         up(&md->mutex);
240
241         return PAGE_SIZE - c;
242 }
243
244 #define W1_MASTER_ATTR_RO(_name, _mode)                         \
245         struct device_attribute w1_master_attribute_##_name =   \
246                 __ATTR(w1_master_##_name, _mode,                \
247                        w1_master_attribute_show_##_name, NULL)
248
249 static W1_MASTER_ATTR_RO(name, S_IRUGO);
250 static W1_MASTER_ATTR_RO(slaves, S_IRUGO);
251 static W1_MASTER_ATTR_RO(slave_count, S_IRUGO);
252 static W1_MASTER_ATTR_RO(max_slave_count, S_IRUGO);
253 static W1_MASTER_ATTR_RO(attempts, S_IRUGO);
254 static W1_MASTER_ATTR_RO(timeout, S_IRUGO);
255 static W1_MASTER_ATTR_RO(pointer, S_IRUGO);
256
257 static struct attribute *w1_master_default_attrs[] = {
258         &w1_master_attribute_name.attr,
259         &w1_master_attribute_slaves.attr,
260         &w1_master_attribute_slave_count.attr,
261         &w1_master_attribute_max_slave_count.attr,
262         &w1_master_attribute_attempts.attr,
263         &w1_master_attribute_timeout.attr,
264         &w1_master_attribute_pointer.attr,
265         NULL
266 };
267
268 static struct attribute_group w1_master_defattr_group = {
269         .attrs = w1_master_default_attrs,
270 };
271
272 int w1_create_master_attributes(struct w1_master *master)
273 {
274         return sysfs_create_group(&master->dev.kobj, &w1_master_defattr_group);
275 }
276
277 void w1_destroy_master_attributes(struct w1_master *master)
278 {
279         sysfs_remove_group(&master->dev.kobj, &w1_master_defattr_group);
280 }
281
282 static int __w1_attach_slave_device(struct w1_slave *sl)
283 {
284         int err;
285
286         sl->dev.parent = &sl->master->dev;
287         sl->dev.driver = sl->master->driver;
288         sl->dev.bus = &w1_bus_type;
289         sl->dev.release = &w1_slave_release;
290
291         snprintf(&sl->dev.bus_id[0], sizeof(sl->dev.bus_id),
292                   "%02x-%012llx",
293                   (unsigned int) sl->reg_num.family,
294                   (unsigned long long) sl->reg_num.id);
295         snprintf (&sl->name[0], sizeof(sl->name),
296                   "%02x-%012llx",
297                   (unsigned int) sl->reg_num.family,
298                   (unsigned long long) sl->reg_num.id);
299
300         dev_dbg(&sl->dev, "%s: registering %s.\n", __func__,
301                 &sl->dev.bus_id[0]);
302
303         err = device_register(&sl->dev);
304         if (err < 0) {
305                 dev_err(&sl->dev,
306                          "Device registration [%s] failed. err=%d\n",
307                          sl->dev.bus_id, err);
308                 return err;
309         }
310
311         memcpy(&sl->attr_bin, &w1_slave_bin_attribute, sizeof(sl->attr_bin));
312         memcpy(&sl->attr_name, &w1_slave_attribute, sizeof(sl->attr_name));
313         memcpy(&sl->attr_val, &w1_slave_attribute_val, sizeof(sl->attr_val));
314
315         sl->attr_bin.read = sl->family->fops->rbin;
316         sl->attr_name.show = sl->family->fops->rname;
317         sl->attr_val.show = sl->family->fops->rval;
318         sl->attr_val.attr.name = sl->family->fops->rvalname;
319
320         err = device_create_file(&sl->dev, &sl->attr_name);
321         if (err < 0) {
322                 dev_err(&sl->dev,
323                          "sysfs file creation for [%s] failed. err=%d\n",
324                          sl->dev.bus_id, err);
325                 device_unregister(&sl->dev);
326                 return err;
327         }
328
329         err = device_create_file(&sl->dev, &sl->attr_val);
330         if (err < 0) {
331                 dev_err(&sl->dev,
332                          "sysfs file creation for [%s] failed. err=%d\n",
333                          sl->dev.bus_id, err);
334                 device_remove_file(&sl->dev, &sl->attr_name);
335                 device_unregister(&sl->dev);
336                 return err;
337         }
338
339         err = sysfs_create_bin_file(&sl->dev.kobj, &sl->attr_bin);
340         if (err < 0) {
341                 dev_err(&sl->dev,
342                          "sysfs file creation for [%s] failed. err=%d\n",
343                          sl->dev.bus_id, err);
344                 device_remove_file(&sl->dev, &sl->attr_name);
345                 device_remove_file(&sl->dev, &sl->attr_val);
346                 device_unregister(&sl->dev);
347                 return err;
348         }
349
350         list_add_tail(&sl->w1_slave_entry, &sl->master->slist);
351
352         return 0;
353 }
354
355 static int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
356 {
357         struct w1_slave *sl;
358         struct w1_family *f;
359         int err;
360         struct w1_netlink_msg msg;
361
362         sl = kmalloc(sizeof(struct w1_slave), GFP_KERNEL);
363         if (!sl) {
364                 dev_err(&dev->dev,
365                          "%s: failed to allocate new slave device.\n",
366                          __func__);
367                 return -ENOMEM;
368         }
369
370         memset(sl, 0, sizeof(*sl));
371
372         sl->owner = THIS_MODULE;
373         sl->master = dev;
374         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
375
376         memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));
377         atomic_set(&sl->refcnt, 0);
378         init_completion(&sl->dev_released);
379
380         spin_lock(&w1_flock);
381         f = w1_family_registered(rn->family);
382         if (!f) {
383                 spin_unlock(&w1_flock);
384                 dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n",
385                           rn->family, rn->family,
386                           (unsigned long long)rn->id, rn->crc);
387                 kfree(sl);
388                 return -ENODEV;
389         }
390         __w1_family_get(f);
391         spin_unlock(&w1_flock);
392
393         sl->family = f;
394
395
396         err = __w1_attach_slave_device(sl);
397         if (err < 0) {
398                 dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__,
399                          sl->name);
400                 w1_family_put(sl->family);
401                 kfree(sl);
402                 return err;
403         }
404
405         sl->ttl = dev->slave_ttl;
406         dev->slave_count++;
407
408         memcpy(&msg.id.id, rn, sizeof(msg.id.id));
409         msg.type = W1_SLAVE_ADD;
410         w1_netlink_send(dev, &msg);
411
412         return 0;
413 }
414
415 static void w1_slave_detach(struct w1_slave *sl)
416 {
417         struct w1_netlink_msg msg;
418
419         dev_info(&sl->dev, "%s: detaching %s.\n", __func__, sl->name);
420
421         while (atomic_read(&sl->refcnt)) {
422                 printk(KERN_INFO "Waiting for %s to become free: refcnt=%d.\n",
423                                 sl->name, atomic_read(&sl->refcnt));
424
425                 if (msleep_interruptible(1000))
426                         flush_signals(current);
427         }
428
429         sysfs_remove_bin_file (&sl->dev.kobj, &sl->attr_bin);
430         device_remove_file(&sl->dev, &sl->attr_name);
431         device_remove_file(&sl->dev, &sl->attr_val);
432         device_unregister(&sl->dev);
433         w1_family_put(sl->family);
434
435         memcpy(&msg.id.id, &sl->reg_num, sizeof(msg.id.id));
436         msg.type = W1_SLAVE_REMOVE;
437         w1_netlink_send(sl->master, &msg);
438 }
439
440 static struct w1_master *w1_search_master(unsigned long data)
441 {
442         struct w1_master *dev;
443         int found = 0;
444
445         spin_lock_bh(&w1_mlock);
446         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
447                 if (dev->bus_master->data == data) {
448                         found = 1;
449                         atomic_inc(&dev->refcnt);
450                         break;
451                 }
452         }
453         spin_unlock_bh(&w1_mlock);
454
455         return (found)?dev:NULL;
456 }
457
458 static void w1_slave_found(unsigned long data, u64 rn)
459 {
460         int slave_count;
461         struct w1_slave *sl;
462         struct list_head *ent;
463         struct w1_reg_num *tmp;
464         int family_found = 0;
465         struct w1_master *dev;
466
467         dev = w1_search_master(data);
468         if (!dev) {
469                 printk(KERN_ERR "Failed to find w1 master device for data %08lx, it is impossible.\n",
470                                 data);
471                 return;
472         }
473
474         tmp = (struct w1_reg_num *) &rn;
475
476         slave_count = 0;
477         list_for_each(ent, &dev->slist) {
478
479                 sl = list_entry(ent, struct w1_slave, w1_slave_entry);
480
481                 if (sl->reg_num.family == tmp->family &&
482                     sl->reg_num.id == tmp->id &&
483                     sl->reg_num.crc == tmp->crc) {
484                         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
485                         break;
486                 } else if (sl->reg_num.family == tmp->family) {
487                         family_found = 1;
488                         break;
489                 }
490
491                 slave_count++;
492         }
493
494         rn = cpu_to_le64(rn);
495
496         if (slave_count == dev->slave_count &&
497                 rn && ((le64_to_cpu(rn) >> 56) & 0xff) == w1_calc_crc8((u8 *)&rn, 7)) {
498                 w1_attach_slave_device(dev, tmp);
499         }
500
501         atomic_dec(&dev->refcnt);
502 }
503
504 void w1_search(struct w1_master *dev)
505 {
506         u64 last, rn, tmp;
507         int i, count = 0;
508         int last_family_desc, last_zero, last_device;
509         int search_bit, id_bit, comp_bit, desc_bit;
510
511         search_bit = id_bit = comp_bit = 0;
512         rn = tmp = last = 0;
513         last_device = last_zero = last_family_desc = 0;
514
515         desc_bit = 64;
516
517         while (!(id_bit && comp_bit) && !last_device &&
518                count++ < dev->max_slave_count) {
519                 last = rn;
520                 rn = 0;
521
522                 last_family_desc = 0;
523
524                 /*
525                  * Reset bus and all 1-wire device state machines
526                  * so they can respond to our requests.
527                  *
528                  * Return 0 - device(s) present, 1 - no devices present.
529                  */
530                 if (w1_reset_bus(dev)) {
531                         dev_info(&dev->dev, "No devices present on the wire.\n");
532                         break;
533                 }
534
535 #if 1
536                 w1_write_8(dev, W1_SEARCH);
537                 for (i = 0; i < 64; ++i) {
538                         /*
539                          * Read 2 bits from bus.
540                          * All who don't sleep must send ID bit and COMPLEMENT ID bit.
541                          * They actually are ANDed between all senders.
542                          */
543                         id_bit = w1_touch_bit(dev, 1);
544                         comp_bit = w1_touch_bit(dev, 1);
545
546                         if (id_bit && comp_bit)
547                                 break;
548
549                         if (id_bit == 0 && comp_bit == 0) {
550                                 if (i == desc_bit)
551                                         search_bit = 1;
552                                 else if (i > desc_bit)
553                                         search_bit = 0;
554                                 else
555                                         search_bit = ((last >> i) & 0x1);
556
557                                 if (search_bit == 0) {
558                                         last_zero = i;
559                                         if (last_zero < 9)
560                                                 last_family_desc = last_zero;
561                                 }
562
563                         } else
564                                 search_bit = id_bit;
565
566                         tmp = search_bit;
567                         rn |= (tmp << i);
568
569                         /*
570                          * Write 1 bit to bus
571                          * and make all who don't have "search_bit" in "i"'th position
572                          * in it's registration number sleep.
573                          */
574                         if (dev->bus_master->touch_bit)
575                                 w1_touch_bit(dev, search_bit);
576                         else
577                                 w1_write_bit(dev, search_bit);
578
579                 }
580 #endif
581
582                 if (desc_bit == last_zero)
583                         last_device = 1;
584
585                 desc_bit = last_zero;
586
587                 w1_slave_found(dev->bus_master->data, rn);
588         }
589 }
590
591 static int w1_control(void *data)
592 {
593         struct w1_slave *sl, *sln;
594         struct w1_master *dev, *n;
595         int err, have_to_wait = 0;
596
597         daemonize("w1_control");
598         allow_signal(SIGTERM);
599
600         while (!control_needs_exit || have_to_wait) {
601                 have_to_wait = 0;
602
603                 try_to_freeze(PF_FREEZE);
604                 msleep_interruptible(w1_timeout * 1000);
605
606                 if (signal_pending(current))
607                         flush_signals(current);
608
609                 list_for_each_entry_safe(dev, n, &w1_masters, w1_master_entry) {
610                         if (!control_needs_exit && !dev->need_exit)
611                                 continue;
612                         /*
613                          * Little race: we can create thread but not set the flag.
614                          * Get a chance for external process to set flag up.
615                          */
616                         if (!dev->initialized) {
617                                 have_to_wait = 1;
618                                 continue;
619                         }
620
621                         spin_lock_bh(&w1_mlock);
622                         list_del(&dev->w1_master_entry);
623                         spin_unlock_bh(&w1_mlock);
624
625                         if (control_needs_exit) {
626                                 dev->need_exit = 1;
627
628                                 err = kill_proc(dev->kpid, SIGTERM, 1);
629                                 if (err)
630                                         dev_err(&dev->dev,
631                                                  "Failed to send signal to w1 kernel thread %d.\n",
632                                                  dev->kpid);
633                         }
634
635                         wait_for_completion(&dev->dev_exited);
636
637                         list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
638                                 list_del(&sl->w1_slave_entry);
639
640                                 w1_slave_detach(sl);
641                                 kfree(sl);
642                         }
643                         w1_destroy_master_attributes(dev);
644                         atomic_dec(&dev->refcnt);
645                 }
646         }
647
648         complete_and_exit(&w1_control_complete, 0);
649 }
650
651 int w1_process(void *data)
652 {
653         struct w1_master *dev = (struct w1_master *) data;
654         struct w1_slave *sl, *sln;
655
656         daemonize("%s", dev->name);
657         allow_signal(SIGTERM);
658
659         while (!dev->need_exit) {
660                 try_to_freeze(PF_FREEZE);
661                 msleep_interruptible(w1_timeout * 1000);
662
663                 if (signal_pending(current))
664                         flush_signals(current);
665
666                 if (dev->need_exit)
667                         break;
668
669                 if (!dev->initialized)
670                         continue;
671
672                 if (down_interruptible(&dev->mutex))
673                         continue;
674
675                 list_for_each_entry(sl, &dev->slist, w1_slave_entry)
676                                 clear_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
677
678                 w1_search_devices(dev, w1_slave_found);
679
680                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
681                         if (!test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags) && !--sl->ttl) {
682                                 list_del (&sl->w1_slave_entry);
683
684                                 w1_slave_detach (sl);
685                                 kfree (sl);
686
687                                 dev->slave_count--;
688                         } else if (test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags))
689                                 sl->ttl = dev->slave_ttl;
690                 }
691                 up(&dev->mutex);
692         }
693
694         atomic_dec(&dev->refcnt);
695         complete_and_exit(&dev->dev_exited, 0);
696
697         return 0;
698 }
699
700 static int w1_init(void)
701 {
702         int retval;
703
704         printk(KERN_INFO "Driver for 1-wire Dallas network protocol.\n");
705
706         retval = bus_register(&w1_bus_type);
707         if (retval) {
708                 printk(KERN_ERR "Failed to register bus. err=%d.\n", retval);
709                 goto err_out_exit_init;
710         }
711
712         retval = driver_register(&w1_driver);
713         if (retval) {
714                 printk(KERN_ERR
715                         "Failed to register master driver. err=%d.\n",
716                         retval);
717                 goto err_out_bus_unregister;
718         }
719
720         control_thread = kernel_thread(&w1_control, NULL, 0);
721         if (control_thread < 0) {
722                 printk(KERN_ERR "Failed to create control thread. err=%d\n",
723                         control_thread);
724                 retval = control_thread;
725                 goto err_out_driver_unregister;
726         }
727
728         return 0;
729
730 err_out_driver_unregister:
731         driver_unregister(&w1_driver);
732
733 err_out_bus_unregister:
734         bus_unregister(&w1_bus_type);
735
736 err_out_exit_init:
737         return retval;
738 }
739
740 static void w1_fini(void)
741 {
742         struct w1_master *dev;
743
744         list_for_each_entry(dev, &w1_masters, w1_master_entry)
745                 __w1_remove_master_device(dev);
746
747         control_needs_exit = 1;
748         wait_for_completion(&w1_control_complete);
749
750         driver_unregister(&w1_driver);
751         bus_unregister(&w1_bus_type);
752 }
753
754 module_init(w1_init);
755 module_exit(w1_fini);