24a192e3b8b40695bcc957e796408873a76ecfe9
[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 bus_type w1_bus_type = {
103         .name = "w1",
104         .match = w1_master_match,
105 };
106
107 struct device_driver w1_driver = {
108         .name = "w1_driver",
109         .bus = &w1_bus_type,
110         .probe = w1_master_probe,
111         .remove = w1_master_remove,
112 };
113
114 struct device w1_device = {
115         .parent = NULL,
116         .bus = &w1_bus_type,
117         .bus_id = "w1 bus master",
118         .driver = &w1_driver,
119         .release = &w1_master_release
120 };
121
122 static struct device_attribute w1_slave_attribute = {
123         .attr = {
124                         .name = "name",
125                         .mode = S_IRUGO,
126                         .owner = THIS_MODULE
127         },
128         .show = &w1_default_read_name,
129 };
130
131 static struct device_attribute w1_slave_attribute_val = {
132         .attr = {
133                         .name = "value",
134                         .mode = S_IRUGO,
135                         .owner = THIS_MODULE
136         },
137         .show = &w1_default_read_name,
138 };
139
140 static ssize_t w1_master_attribute_show_name(struct device *dev, struct device_attribute *attr, char *buf)
141 {
142         struct w1_master *md = container_of (dev, struct w1_master, dev);
143         ssize_t count;
144         
145         if (down_interruptible (&md->mutex))
146                 return -EBUSY;
147
148         count = sprintf(buf, "%s\n", md->name);
149         
150         up(&md->mutex);
151
152         return count;
153 }
154
155 static ssize_t w1_master_attribute_show_pointer(struct device *dev, struct device_attribute *attr, char *buf)
156 {
157         struct w1_master *md = container_of(dev, struct w1_master, dev);
158         ssize_t count;
159         
160         if (down_interruptible(&md->mutex))
161                 return -EBUSY;
162
163         count = sprintf(buf, "0x%p\n", md->bus_master);
164         
165         up(&md->mutex);
166         return count;
167 }
168
169 static ssize_t w1_master_attribute_show_timeout(struct device *dev, struct device_attribute *attr, char *buf)
170 {
171         ssize_t count;
172         count = sprintf(buf, "%d\n", w1_timeout);
173         return count;
174 }
175
176 static ssize_t w1_master_attribute_show_max_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
177 {
178         struct w1_master *md = container_of(dev, struct w1_master, dev);
179         ssize_t count;
180         
181         if (down_interruptible(&md->mutex))
182                 return -EBUSY;
183
184         count = sprintf(buf, "%d\n", md->max_slave_count);
185         
186         up(&md->mutex);
187         return count;
188 }
189
190 static ssize_t w1_master_attribute_show_attempts(struct device *dev, struct device_attribute *attr, char *buf)
191 {
192         struct w1_master *md = container_of(dev, struct w1_master, dev);
193         ssize_t count;
194         
195         if (down_interruptible(&md->mutex))
196                 return -EBUSY;
197
198         count = sprintf(buf, "%lu\n", md->attempts);
199         
200         up(&md->mutex);
201         return count;
202 }
203
204 static ssize_t w1_master_attribute_show_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
205 {
206         struct w1_master *md = container_of(dev, struct w1_master, dev);
207         ssize_t count;
208         
209         if (down_interruptible(&md->mutex))
210                 return -EBUSY;
211
212         count = sprintf(buf, "%d\n", md->slave_count);
213         
214         up(&md->mutex);
215         return count;
216 }
217
218 static ssize_t w1_master_attribute_show_slaves(struct device *dev, struct device_attribute *attr, char *buf)
219
220 {
221         struct w1_master *md = container_of(dev, struct w1_master, dev);
222         int c = PAGE_SIZE;
223
224         if (down_interruptible(&md->mutex))
225                 return -EBUSY;
226
227         if (md->slave_count == 0)
228                 c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n");
229         else {
230                 struct list_head *ent, *n;
231                 struct w1_slave *sl;
232
233                 list_for_each_safe(ent, n, &md->slist) {
234                         sl = list_entry(ent, struct w1_slave, w1_slave_entry);
235
236                         c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", sl->name);
237                 }
238         }
239
240         up(&md->mutex);
241
242         return PAGE_SIZE - c;
243 }
244
245 static struct device_attribute w1_master_attribute_slaves = {
246         .attr = {
247                         .name = "w1_master_slaves",
248                         .mode = S_IRUGO,
249                         .owner = THIS_MODULE,
250         },
251         .show = &w1_master_attribute_show_slaves,
252 };
253 static struct device_attribute w1_master_attribute_slave_count = {
254         .attr = {
255                         .name = "w1_master_slave_count",
256                         .mode = S_IRUGO,
257                         .owner = THIS_MODULE
258         },
259         .show = &w1_master_attribute_show_slave_count,
260 };
261 static struct device_attribute w1_master_attribute_attempts = {
262         .attr = {
263                         .name = "w1_master_attempts",
264                         .mode = S_IRUGO,
265                         .owner = THIS_MODULE
266         },
267         .show = &w1_master_attribute_show_attempts,
268 };
269 static struct device_attribute w1_master_attribute_max_slave_count = {
270         .attr = {
271                         .name = "w1_master_max_slave_count",
272                         .mode = S_IRUGO,
273                         .owner = THIS_MODULE
274         },
275         .show = &w1_master_attribute_show_max_slave_count,
276 };
277 static struct device_attribute w1_master_attribute_timeout = {
278         .attr = {
279                         .name = "w1_master_timeout",
280                         .mode = S_IRUGO,
281                         .owner = THIS_MODULE
282         },
283         .show = &w1_master_attribute_show_timeout,
284 };
285 static struct device_attribute w1_master_attribute_pointer = {
286         .attr = {
287                         .name = "w1_master_pointer",
288                         .mode = S_IRUGO,
289                         .owner = THIS_MODULE
290         },
291         .show = &w1_master_attribute_show_pointer,
292 };
293 static struct device_attribute w1_master_attribute_name = {
294         .attr = {
295                         .name = "w1_master_name",
296                         .mode = S_IRUGO,
297                         .owner = THIS_MODULE
298         },
299         .show = &w1_master_attribute_show_name,
300 };
301
302 static struct bin_attribute w1_slave_bin_attribute = {
303         .attr = {
304                         .name = "w1_slave",
305                         .mode = S_IRUGO,
306                         .owner = THIS_MODULE,
307         },
308         .size = W1_SLAVE_DATA_SIZE,
309         .read = &w1_default_read_bin,
310 };
311
312 static int __w1_attach_slave_device(struct w1_slave *sl)
313 {
314         int err;
315
316         sl->dev.parent = &sl->master->dev;
317         sl->dev.driver = sl->master->driver;
318         sl->dev.bus = &w1_bus_type;
319         sl->dev.release = &w1_slave_release;
320
321         snprintf(&sl->dev.bus_id[0], sizeof(sl->dev.bus_id),
322                   "%02x-%012llx",
323                   (unsigned int) sl->reg_num.family,
324                   (unsigned long long) sl->reg_num.id);
325         snprintf (&sl->name[0], sizeof(sl->name),
326                   "%02x-%012llx",
327                   (unsigned int) sl->reg_num.family,
328                   (unsigned long long) sl->reg_num.id);
329
330         dev_dbg(&sl->dev, "%s: registering %s.\n", __func__,
331                 &sl->dev.bus_id[0]);
332
333         err = device_register(&sl->dev);
334         if (err < 0) {
335                 dev_err(&sl->dev,
336                          "Device registration [%s] failed. err=%d\n",
337                          sl->dev.bus_id, err);
338                 return err;
339         }
340
341         memcpy(&sl->attr_bin, &w1_slave_bin_attribute, sizeof(sl->attr_bin));
342         memcpy(&sl->attr_name, &w1_slave_attribute, sizeof(sl->attr_name));
343         memcpy(&sl->attr_val, &w1_slave_attribute_val, sizeof(sl->attr_val));
344         
345         sl->attr_bin.read = sl->family->fops->rbin;
346         sl->attr_name.show = sl->family->fops->rname;
347         sl->attr_val.show = sl->family->fops->rval;
348         sl->attr_val.attr.name = sl->family->fops->rvalname;
349
350         err = device_create_file(&sl->dev, &sl->attr_name);
351         if (err < 0) {
352                 dev_err(&sl->dev,
353                          "sysfs file creation for [%s] failed. err=%d\n",
354                          sl->dev.bus_id, err);
355                 device_unregister(&sl->dev);
356                 return err;
357         }
358
359         err = device_create_file(&sl->dev, &sl->attr_val);
360         if (err < 0) {
361                 dev_err(&sl->dev,
362                          "sysfs file creation for [%s] failed. err=%d\n",
363                          sl->dev.bus_id, err);
364                 device_remove_file(&sl->dev, &sl->attr_name);
365                 device_unregister(&sl->dev);
366                 return err;
367         }
368
369         err = sysfs_create_bin_file(&sl->dev.kobj, &sl->attr_bin);
370         if (err < 0) {
371                 dev_err(&sl->dev,
372                          "sysfs file creation for [%s] failed. err=%d\n",
373                          sl->dev.bus_id, err);
374                 device_remove_file(&sl->dev, &sl->attr_name);
375                 device_remove_file(&sl->dev, &sl->attr_val);
376                 device_unregister(&sl->dev);
377                 return err;
378         }
379
380         list_add_tail(&sl->w1_slave_entry, &sl->master->slist);
381
382         return 0;
383 }
384
385 static int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
386 {
387         struct w1_slave *sl;
388         struct w1_family *f;
389         int err;
390         struct w1_netlink_msg msg;
391
392         sl = kmalloc(sizeof(struct w1_slave), GFP_KERNEL);
393         if (!sl) {
394                 dev_err(&dev->dev,
395                          "%s: failed to allocate new slave device.\n",
396                          __func__);
397                 return -ENOMEM;
398         }
399
400         memset(sl, 0, sizeof(*sl));
401
402         sl->owner = THIS_MODULE;
403         sl->master = dev;
404         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
405
406         memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));
407         atomic_set(&sl->refcnt, 0);
408         init_completion(&sl->dev_released);
409
410         spin_lock(&w1_flock);
411         f = w1_family_registered(rn->family);
412         if (!f) {
413                 spin_unlock(&w1_flock);
414                 dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n",
415                           rn->family, rn->family,
416                           (unsigned long long)rn->id, rn->crc);
417                 kfree(sl);
418                 return -ENODEV;
419         }
420         __w1_family_get(f);
421         spin_unlock(&w1_flock);
422
423         sl->family = f;
424
425
426         err = __w1_attach_slave_device(sl);
427         if (err < 0) {
428                 dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__,
429                          sl->name);
430                 w1_family_put(sl->family);
431                 kfree(sl);
432                 return err;
433         }
434
435         sl->ttl = dev->slave_ttl;
436         dev->slave_count++;
437
438         memcpy(&msg.id.id, rn, sizeof(msg.id.id));
439         msg.type = W1_SLAVE_ADD;
440         w1_netlink_send(dev, &msg);
441
442         return 0;
443 }
444
445 static void w1_slave_detach(struct w1_slave *sl)
446 {
447         struct w1_netlink_msg msg;
448         
449         dev_info(&sl->dev, "%s: detaching %s.\n", __func__, sl->name);
450
451         while (atomic_read(&sl->refcnt)) {
452                 printk(KERN_INFO "Waiting for %s to become free: refcnt=%d.\n",
453                                 sl->name, atomic_read(&sl->refcnt));
454
455                 if (msleep_interruptible(1000))
456                         flush_signals(current);
457         }
458
459         sysfs_remove_bin_file (&sl->dev.kobj, &sl->attr_bin);
460         device_remove_file(&sl->dev, &sl->attr_name);
461         device_remove_file(&sl->dev, &sl->attr_val);
462         device_unregister(&sl->dev);
463         w1_family_put(sl->family);
464
465         memcpy(&msg.id.id, &sl->reg_num, sizeof(msg.id.id));
466         msg.type = W1_SLAVE_REMOVE;
467         w1_netlink_send(sl->master, &msg);
468 }
469
470 static struct w1_master *w1_search_master(unsigned long data)
471 {
472         struct w1_master *dev;
473         int found = 0;
474         
475         spin_lock_irq(&w1_mlock);
476         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
477                 if (dev->bus_master->data == data) {
478                         found = 1;
479                         atomic_inc(&dev->refcnt);
480                         break;
481                 }
482         }
483         spin_unlock_irq(&w1_mlock);
484
485         return (found)?dev:NULL;
486 }
487
488 void w1_slave_found(unsigned long data, u64 rn)
489 {
490         int slave_count;
491         struct w1_slave *sl;
492         struct list_head *ent;
493         struct w1_reg_num *tmp;
494         int family_found = 0;
495         struct w1_master *dev;
496
497         dev = w1_search_master(data);
498         if (!dev) {
499                 printk(KERN_ERR "Failed to find w1 master device for data %08lx, it is impossible.\n",
500                                 data);
501                 return;
502         }
503         
504         tmp = (struct w1_reg_num *) &rn;
505
506         slave_count = 0;
507         list_for_each(ent, &dev->slist) {
508
509                 sl = list_entry(ent, struct w1_slave, w1_slave_entry);
510
511                 if (sl->reg_num.family == tmp->family &&
512                     sl->reg_num.id == tmp->id &&
513                     sl->reg_num.crc == tmp->crc) {
514                         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
515                         break;
516                 }
517                 else if (sl->reg_num.family == tmp->family) {
518                         family_found = 1;
519                         break;
520                 }
521
522                 slave_count++;
523         }
524
525         rn = cpu_to_le64(rn);
526
527         if (slave_count == dev->slave_count &&
528                 rn && ((le64_to_cpu(rn) >> 56) & 0xff) == w1_calc_crc8((u8 *)&rn, 7)) {
529                 w1_attach_slave_device(dev, tmp);
530         }
531                         
532         atomic_dec(&dev->refcnt);
533 }
534
535 void w1_search(struct w1_master *dev)
536 {
537         u64 last, rn, tmp;
538         int i, count = 0;
539         int last_family_desc, last_zero, last_device;
540         int search_bit, id_bit, comp_bit, desc_bit;
541
542         search_bit = id_bit = comp_bit = 0;
543         rn = tmp = last = 0;
544         last_device = last_zero = last_family_desc = 0;
545
546         desc_bit = 64;
547
548         while (!(id_bit && comp_bit) && !last_device
549                 && count++ < dev->max_slave_count) {
550                 last = rn;
551                 rn = 0;
552
553                 last_family_desc = 0;
554
555                 /*
556                  * Reset bus and all 1-wire device state machines
557                  * so they can respond to our requests.
558                  *
559                  * Return 0 - device(s) present, 1 - no devices present.
560                  */
561                 if (w1_reset_bus(dev)) {
562                         dev_info(&dev->dev, "No devices present on the wire.\n");
563                         break;
564                 }
565
566 #if 1
567                 w1_write_8(dev, W1_SEARCH);
568                 for (i = 0; i < 64; ++i) {
569                         /*
570                          * Read 2 bits from bus.
571                          * All who don't sleep must send ID bit and COMPLEMENT ID bit.
572                          * They actually are ANDed between all senders.
573                          */
574                         id_bit = w1_touch_bit(dev, 1);
575                         comp_bit = w1_touch_bit(dev, 1);
576
577                         if (id_bit && comp_bit)
578                                 break;
579
580                         if (id_bit == 0 && comp_bit == 0) {
581                                 if (i == desc_bit)
582                                         search_bit = 1;
583                                 else if (i > desc_bit)
584                                         search_bit = 0;
585                                 else
586                                         search_bit = ((last >> i) & 0x1);
587
588                                 if (search_bit == 0) {
589                                         last_zero = i;
590                                         if (last_zero < 9)
591                                                 last_family_desc = last_zero;
592                                 }
593
594                         }
595                         else
596                                 search_bit = id_bit;
597
598                         tmp = search_bit;
599                         rn |= (tmp << i);
600
601                         /*
602                          * Write 1 bit to bus
603                          * and make all who don't have "search_bit" in "i"'th position
604                          * in it's registration number sleep.
605                          */
606                         if (dev->bus_master->touch_bit)
607                                 w1_touch_bit(dev, search_bit);
608                         else
609                                 w1_write_bit(dev, search_bit);
610
611                 }
612 #endif
613
614                 if (desc_bit == last_zero)
615                         last_device = 1;
616
617                 desc_bit = last_zero;
618         
619                 w1_slave_found(dev->bus_master->data, rn);
620         }
621 }
622
623 int w1_create_master_attributes(struct w1_master *dev)
624 {
625         if (    device_create_file(&dev->dev, &w1_master_attribute_slaves) < 0 ||
626                 device_create_file(&dev->dev, &w1_master_attribute_slave_count) < 0 ||
627                 device_create_file(&dev->dev, &w1_master_attribute_attempts) < 0 ||
628                 device_create_file(&dev->dev, &w1_master_attribute_max_slave_count) < 0 ||
629                 device_create_file(&dev->dev, &w1_master_attribute_timeout) < 0||
630                 device_create_file(&dev->dev, &w1_master_attribute_pointer) < 0||
631                 device_create_file(&dev->dev, &w1_master_attribute_name) < 0)
632                 return -EINVAL;
633
634         return 0;
635 }
636
637 void w1_destroy_master_attributes(struct w1_master *dev)
638 {
639         device_remove_file(&dev->dev, &w1_master_attribute_slaves);
640         device_remove_file(&dev->dev, &w1_master_attribute_slave_count);
641         device_remove_file(&dev->dev, &w1_master_attribute_attempts);
642         device_remove_file(&dev->dev, &w1_master_attribute_max_slave_count);
643         device_remove_file(&dev->dev, &w1_master_attribute_timeout);
644         device_remove_file(&dev->dev, &w1_master_attribute_pointer);
645         device_remove_file(&dev->dev, &w1_master_attribute_name);
646 }
647
648
649 int w1_control(void *data)
650 {
651         struct w1_slave *sl;
652         struct w1_master *dev;
653         struct list_head *ent, *ment, *n, *mn;
654         int err, have_to_wait = 0;
655
656         daemonize("w1_control");
657         allow_signal(SIGTERM);
658
659         while (!control_needs_exit || have_to_wait) {
660                 have_to_wait = 0;
661
662                 try_to_freeze(PF_FREEZE);
663                 msleep_interruptible(w1_timeout * 1000);
664
665                 if (signal_pending(current))
666                         flush_signals(current);
667
668                 list_for_each_safe(ment, mn, &w1_masters) {
669                         dev = list_entry(ment, struct w1_master, w1_master_entry);
670
671                         if (!control_needs_exit && !dev->need_exit)
672                                 continue;
673                         /*
674                          * Little race: we can create thread but not set the flag.
675                          * Get a chance for external process to set flag up.
676                          */
677                         if (!dev->initialized) {
678                                 have_to_wait = 1;
679                                 continue;
680                         }
681
682                         spin_lock(&w1_mlock);
683                         list_del(&dev->w1_master_entry);
684                         spin_unlock(&w1_mlock);
685
686                         if (control_needs_exit) {
687                                 dev->need_exit = 1;
688
689                                 err = kill_proc(dev->kpid, SIGTERM, 1);
690                                 if (err)
691                                         dev_err(&dev->dev,
692                                                  "Failed to send signal to w1 kernel thread %d.\n",
693                                                  dev->kpid);
694                         }
695
696                         wait_for_completion(&dev->dev_exited);
697
698                         list_for_each_safe(ent, n, &dev->slist) {
699                                 sl = list_entry(ent, struct w1_slave, w1_slave_entry);
700
701                                 if (!sl)
702                                         dev_warn(&dev->dev,
703                                                   "%s: slave entry is NULL.\n",
704                                                   __func__);
705                                 else {
706                                         list_del(&sl->w1_slave_entry);
707
708                                         w1_slave_detach(sl);
709                                         kfree(sl);
710                                 }
711                         }
712                         w1_destroy_master_attributes(dev);
713                         atomic_dec(&dev->refcnt);
714                 }
715         }
716
717         complete_and_exit(&w1_control_complete, 0);
718 }
719
720 int w1_process(void *data)
721 {
722         struct w1_master *dev = (struct w1_master *) data;
723         struct list_head *ent, *n;
724         struct w1_slave *sl;
725
726         daemonize("%s", dev->name);
727         allow_signal(SIGTERM);
728
729         while (!dev->need_exit) {
730                 try_to_freeze(PF_FREEZE);
731                 msleep_interruptible(w1_timeout * 1000);
732
733                 if (signal_pending(current))
734                         flush_signals(current);
735
736                 if (dev->need_exit)
737                         break;
738
739                 if (!dev->initialized)
740                         continue;
741
742                 if (down_interruptible(&dev->mutex))
743                         continue;
744
745                 list_for_each_safe(ent, n, &dev->slist) {
746                         sl = list_entry(ent, struct w1_slave, w1_slave_entry);
747
748                         if (sl)
749                                 clear_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
750                 }
751                 
752                 w1_search_devices(dev, w1_slave_found);
753
754                 list_for_each_safe(ent, n, &dev->slist) {
755                         sl = list_entry(ent, struct w1_slave, w1_slave_entry);
756
757                         if (sl && !test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags) && !--sl->ttl) {
758                                 list_del (&sl->w1_slave_entry);
759
760                                 w1_slave_detach (sl);
761                                 kfree (sl);
762
763                                 dev->slave_count--;
764                         }
765                         else if (test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags))
766                                 sl->ttl = dev->slave_ttl;
767                 }
768                 up(&dev->mutex);
769         }
770
771         atomic_dec(&dev->refcnt);
772         complete_and_exit(&dev->dev_exited, 0);
773
774         return 0;
775 }
776
777 int w1_init(void)
778 {
779         int retval;
780
781         printk(KERN_INFO "Driver for 1-wire Dallas network protocol.\n");
782
783         retval = bus_register(&w1_bus_type);
784         if (retval) {
785                 printk(KERN_ERR "Failed to register bus. err=%d.\n", retval);
786                 goto err_out_exit_init;
787         }
788
789         retval = driver_register(&w1_driver);
790         if (retval) {
791                 printk(KERN_ERR
792                         "Failed to register master driver. err=%d.\n",
793                         retval);
794                 goto err_out_bus_unregister;
795         }
796
797         control_thread = kernel_thread(&w1_control, NULL, 0);
798         if (control_thread < 0) {
799                 printk(KERN_ERR "Failed to create control thread. err=%d\n",
800                         control_thread);
801                 retval = control_thread;
802                 goto err_out_driver_unregister;
803         }
804
805         return 0;
806
807 err_out_driver_unregister:
808         driver_unregister(&w1_driver);
809
810 err_out_bus_unregister:
811         bus_unregister(&w1_bus_type);
812
813 err_out_exit_init:
814         return retval;
815 }
816
817 void w1_fini(void)
818 {
819         struct w1_master *dev;
820         struct list_head *ent, *n;
821
822         list_for_each_safe(ent, n, &w1_masters) {
823                 dev = list_entry(ent, struct w1_master, w1_master_entry);
824                 __w1_remove_master_device(dev);
825         }
826
827         control_needs_exit = 1;
828
829         wait_for_completion(&w1_control_complete);
830
831         driver_unregister(&w1_driver);
832         bus_unregister(&w1_bus_type);
833 }
834
835 module_init(w1_init);
836 module_exit(w1_fini);