Merge with master.kernel.org:/pub/scm/linux/kernel/git/torvalds/linux-2.6.git
[linux-2.6] / 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 /* stuff for the default family */
63 static ssize_t w1_famdefault_read_name(struct device *dev, struct device_attribute *attr, char *buf)
64 {
65         struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
66         return(sprintf(buf, "%s\n", sl->name));
67 }
68 static struct w1_family_ops w1_default_fops = {
69         .rname = &w1_famdefault_read_name,
70 };
71 static struct w1_family w1_default_family = {
72         .fops = &w1_default_fops,
73 };
74
75 static int w1_master_match(struct device *dev, struct device_driver *drv)
76 {
77         return 1;
78 }
79
80 static int w1_master_probe(struct device *dev)
81 {
82         return -ENODEV;
83 }
84
85 static int w1_master_remove(struct device *dev)
86 {
87         return 0;
88 }
89
90 static void w1_master_release(struct device *dev)
91 {
92         struct w1_master *md = container_of(dev, struct w1_master, dev);
93
94         complete(&md->dev_released);
95 }
96
97 static void w1_slave_release(struct device *dev)
98 {
99         struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
100
101         complete(&sl->dev_released);
102 }
103
104 static ssize_t w1_default_read_name(struct device *dev, struct device_attribute *attr, char *buf)
105 {
106         return sprintf(buf, "No family registered.\n");
107 }
108
109 static ssize_t w1_default_read_bin(struct kobject *kobj, char *buf, loff_t off,
110                      size_t count)
111 {
112         return sprintf(buf, "No family registered.\n");
113 }
114
115 static struct device_attribute w1_slave_attribute =
116         __ATTR(name, S_IRUGO, w1_default_read_name, NULL);
117
118 static struct bin_attribute w1_slave_bin_attribute = {
119         .attr = {
120                 .name = "w1_slave",
121                 .mode = S_IRUGO,
122                 .owner = THIS_MODULE,
123         },
124         .size = W1_SLAVE_DATA_SIZE,
125         .read = &w1_default_read_bin,
126 };
127
128
129 static struct bus_type w1_bus_type = {
130         .name = "w1",
131         .match = w1_master_match,
132 };
133
134 struct device_driver w1_driver = {
135         .name = "w1_driver",
136         .bus = &w1_bus_type,
137         .probe = w1_master_probe,
138         .remove = w1_master_remove,
139 };
140
141 struct device w1_device = {
142         .parent = NULL,
143         .bus = &w1_bus_type,
144         .bus_id = "w1 bus master",
145         .driver = &w1_driver,
146         .release = &w1_master_release
147 };
148
149 static ssize_t w1_master_attribute_show_name(struct device *dev, struct device_attribute *attr, char *buf)
150 {
151         struct w1_master *md = container_of(dev, struct w1_master, dev);
152         ssize_t count;
153
154         if (down_interruptible (&md->mutex))
155                 return -EBUSY;
156
157         count = sprintf(buf, "%s\n", md->name);
158
159         up(&md->mutex);
160
161         return count;
162 }
163
164 static ssize_t w1_master_attribute_store_search(struct device * dev,
165                                                 struct device_attribute *attr,
166                                                 const char * buf, size_t count)
167 {
168         struct w1_master *md = container_of(dev, struct w1_master, dev);
169
170         if (down_interruptible (&md->mutex))
171                 return -EBUSY;
172
173         md->search_count = simple_strtol(buf, NULL, 0);
174
175         up(&md->mutex);
176
177         return count;
178 }
179
180 static ssize_t w1_master_attribute_show_search(struct device *dev,
181                                                struct device_attribute *attr,
182                                                char *buf)
183 {
184         struct w1_master *md = container_of(dev, struct w1_master, dev);
185         ssize_t count;
186
187         if (down_interruptible (&md->mutex))
188                 return -EBUSY;
189
190         count = sprintf(buf, "%d\n", md->search_count);
191
192         up(&md->mutex);
193
194         return count;
195 }
196
197 static ssize_t w1_master_attribute_show_pointer(struct device *dev, struct device_attribute *attr, char *buf)
198 {
199         struct w1_master *md = container_of(dev, struct w1_master, dev);
200         ssize_t count;
201
202         if (down_interruptible(&md->mutex))
203                 return -EBUSY;
204
205         count = sprintf(buf, "0x%p\n", md->bus_master);
206
207         up(&md->mutex);
208         return count;
209 }
210
211 static ssize_t w1_master_attribute_show_timeout(struct device *dev, struct device_attribute *attr, char *buf)
212 {
213         ssize_t count;
214         count = sprintf(buf, "%d\n", w1_timeout);
215         return count;
216 }
217
218 static ssize_t w1_master_attribute_show_max_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
219 {
220         struct w1_master *md = container_of(dev, struct w1_master, dev);
221         ssize_t count;
222
223         if (down_interruptible(&md->mutex))
224                 return -EBUSY;
225
226         count = sprintf(buf, "%d\n", md->max_slave_count);
227
228         up(&md->mutex);
229         return count;
230 }
231
232 static ssize_t w1_master_attribute_show_attempts(struct device *dev, struct device_attribute *attr, char *buf)
233 {
234         struct w1_master *md = container_of(dev, struct w1_master, dev);
235         ssize_t count;
236
237         if (down_interruptible(&md->mutex))
238                 return -EBUSY;
239
240         count = sprintf(buf, "%lu\n", md->attempts);
241
242         up(&md->mutex);
243         return count;
244 }
245
246 static ssize_t w1_master_attribute_show_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
247 {
248         struct w1_master *md = container_of(dev, struct w1_master, dev);
249         ssize_t count;
250
251         if (down_interruptible(&md->mutex))
252                 return -EBUSY;
253
254         count = sprintf(buf, "%d\n", md->slave_count);
255
256         up(&md->mutex);
257         return count;
258 }
259
260 static ssize_t w1_master_attribute_show_slaves(struct device *dev, struct device_attribute *attr, char *buf)
261 {
262         struct w1_master *md = container_of(dev, struct w1_master, dev);
263         int c = PAGE_SIZE;
264
265         if (down_interruptible(&md->mutex))
266                 return -EBUSY;
267
268         if (md->slave_count == 0)
269                 c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n");
270         else {
271                 struct list_head *ent, *n;
272                 struct w1_slave *sl;
273
274                 list_for_each_safe(ent, n, &md->slist) {
275                         sl = list_entry(ent, struct w1_slave, w1_slave_entry);
276
277                         c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", sl->name);
278                 }
279         }
280
281         up(&md->mutex);
282
283         return PAGE_SIZE - c;
284 }
285
286 #define W1_MASTER_ATTR_RO(_name, _mode)                         \
287         struct device_attribute w1_master_attribute_##_name =   \
288                 __ATTR(w1_master_##_name, _mode,                \
289                        w1_master_attribute_show_##_name, NULL)
290
291 #define W1_MASTER_ATTR_RW(_name, _mode)                         \
292         struct device_attribute w1_master_attribute_##_name =   \
293                 __ATTR(w1_master_##_name, _mode,                \
294                        w1_master_attribute_show_##_name,        \
295                        w1_master_attribute_store_##_name)
296
297 static W1_MASTER_ATTR_RO(name, S_IRUGO);
298 static W1_MASTER_ATTR_RO(slaves, S_IRUGO);
299 static W1_MASTER_ATTR_RO(slave_count, S_IRUGO);
300 static W1_MASTER_ATTR_RO(max_slave_count, S_IRUGO);
301 static W1_MASTER_ATTR_RO(attempts, S_IRUGO);
302 static W1_MASTER_ATTR_RO(timeout, S_IRUGO);
303 static W1_MASTER_ATTR_RO(pointer, S_IRUGO);
304 static W1_MASTER_ATTR_RW(search, S_IRUGO | S_IWUGO);
305
306 static struct attribute *w1_master_default_attrs[] = {
307         &w1_master_attribute_name.attr,
308         &w1_master_attribute_slaves.attr,
309         &w1_master_attribute_slave_count.attr,
310         &w1_master_attribute_max_slave_count.attr,
311         &w1_master_attribute_attempts.attr,
312         &w1_master_attribute_timeout.attr,
313         &w1_master_attribute_pointer.attr,
314         &w1_master_attribute_search.attr,
315         NULL
316 };
317
318 static struct attribute_group w1_master_defattr_group = {
319         .attrs = w1_master_default_attrs,
320 };
321
322 int w1_create_master_attributes(struct w1_master *master)
323 {
324         return sysfs_create_group(&master->dev.kobj, &w1_master_defattr_group);
325 }
326
327 void w1_destroy_master_attributes(struct w1_master *master)
328 {
329         sysfs_remove_group(&master->dev.kobj, &w1_master_defattr_group);
330 }
331
332 static int __w1_attach_slave_device(struct w1_slave *sl)
333 {
334         int err;
335
336         sl->dev.parent = &sl->master->dev;
337         sl->dev.driver = sl->master->driver;
338         sl->dev.bus = &w1_bus_type;
339         sl->dev.release = &w1_slave_release;
340
341         snprintf(&sl->dev.bus_id[0], sizeof(sl->dev.bus_id),
342                  "%02x-%012llx",
343                  (unsigned int) sl->reg_num.family,
344                  (unsigned long long) sl->reg_num.id);
345         snprintf(&sl->name[0], sizeof(sl->name),
346                  "%02x-%012llx",
347                  (unsigned int) sl->reg_num.family,
348                  (unsigned long long) sl->reg_num.id);
349
350         dev_dbg(&sl->dev, "%s: registering %s.\n", __func__,
351                 &sl->dev.bus_id[0]);
352
353         err = device_register(&sl->dev);
354         if (err < 0) {
355                 dev_err(&sl->dev,
356                         "Device registration [%s] failed. err=%d\n",
357                         sl->dev.bus_id, err);
358                 return err;
359         }
360
361         memcpy(&sl->attr_bin, &w1_slave_bin_attribute, sizeof(sl->attr_bin));
362         memcpy(&sl->attr_name, &w1_slave_attribute, sizeof(sl->attr_name));
363
364         sl->attr_bin.read = sl->family->fops->rbin;
365         sl->attr_name.show = sl->family->fops->rname;
366
367         err = device_create_file(&sl->dev, &sl->attr_name);
368         if (err < 0) {
369                 dev_err(&sl->dev,
370                         "sysfs file creation for [%s] failed. err=%d\n",
371                         sl->dev.bus_id, err);
372                 device_unregister(&sl->dev);
373                 return err;
374         }
375
376         if ( sl->attr_bin.read ) {
377                 err = sysfs_create_bin_file(&sl->dev.kobj, &sl->attr_bin);
378                 if (err < 0) {
379                         dev_err(&sl->dev,
380                                 "sysfs file creation for [%s] failed. err=%d\n",
381                                 sl->dev.bus_id, err);
382                         device_remove_file(&sl->dev, &sl->attr_name);
383                         device_unregister(&sl->dev);
384                         return err;
385                 }
386         }
387
388         list_add_tail(&sl->w1_slave_entry, &sl->master->slist);
389
390         return 0;
391 }
392
393 static int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
394 {
395         struct w1_slave *sl;
396         struct w1_family *f;
397         int err;
398         struct w1_netlink_msg msg;
399
400         sl = kmalloc(sizeof(struct w1_slave), GFP_KERNEL);
401         if (!sl) {
402                 dev_err(&dev->dev,
403                          "%s: failed to allocate new slave device.\n",
404                          __func__);
405                 return -ENOMEM;
406         }
407
408         memset(sl, 0, sizeof(*sl));
409
410         sl->owner = THIS_MODULE;
411         sl->master = dev;
412         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
413
414         memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));
415         atomic_set(&sl->refcnt, 0);
416         init_completion(&sl->dev_released);
417
418         spin_lock(&w1_flock);
419         f = w1_family_registered(rn->family);
420         if (!f) {
421                 f= &w1_default_family;
422                 dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n",
423                           rn->family, rn->family,
424                           (unsigned long long)rn->id, rn->crc);
425         }
426         __w1_family_get(f);
427         spin_unlock(&w1_flock);
428
429         sl->family = f;
430
431
432         err = __w1_attach_slave_device(sl);
433         if (err < 0) {
434                 dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__,
435                          sl->name);
436                 w1_family_put(sl->family);
437                 kfree(sl);
438                 return err;
439         }
440
441         sl->ttl = dev->slave_ttl;
442         dev->slave_count++;
443
444         memcpy(&msg.id.id, rn, sizeof(msg.id.id));
445         msg.type = W1_SLAVE_ADD;
446         w1_netlink_send(dev, &msg);
447
448         return 0;
449 }
450
451 static void w1_slave_detach(struct w1_slave *sl)
452 {
453         struct w1_netlink_msg msg;
454
455         dev_info(&sl->dev, "%s: detaching %s.\n", __func__, sl->name);
456
457         while (atomic_read(&sl->refcnt)) {
458                 printk(KERN_INFO "Waiting for %s to become free: refcnt=%d.\n",
459                                 sl->name, atomic_read(&sl->refcnt));
460
461                 if (msleep_interruptible(1000))
462                         flush_signals(current);
463         }
464
465         if ( sl->attr_bin.read ) {
466                 sysfs_remove_bin_file (&sl->dev.kobj, &sl->attr_bin);
467         }
468         device_remove_file(&sl->dev, &sl->attr_name);
469         device_unregister(&sl->dev);
470         w1_family_put(sl->family);
471
472         sl->master->slave_count--;
473
474         memcpy(&msg.id.id, &sl->reg_num, sizeof(msg.id.id));
475         msg.type = W1_SLAVE_REMOVE;
476         w1_netlink_send(sl->master, &msg);
477 }
478
479 static struct w1_master *w1_search_master(unsigned long data)
480 {
481         struct w1_master *dev;
482         int found = 0;
483
484         spin_lock_bh(&w1_mlock);
485         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
486                 if (dev->bus_master->data == data) {
487                         found = 1;
488                         atomic_inc(&dev->refcnt);
489                         break;
490                 }
491         }
492         spin_unlock_bh(&w1_mlock);
493
494         return (found)?dev:NULL;
495 }
496
497 void w1_reconnect_slaves(struct w1_family *f)
498 {
499         struct w1_master *dev;
500
501         spin_lock_bh(&w1_mlock);
502         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
503                 dev_info(&dev->dev, "Reconnecting slaves in %s into new family %02x.\n",
504                                 dev->name, f->fid);
505                 set_bit(W1_MASTER_NEED_RECONNECT, &dev->flags);
506         }
507         spin_unlock_bh(&w1_mlock);
508 }
509
510
511 static void w1_slave_found(unsigned long data, u64 rn)
512 {
513         int slave_count;
514         struct w1_slave *sl;
515         struct list_head *ent;
516         struct w1_reg_num *tmp;
517         int family_found = 0;
518         struct w1_master *dev;
519
520         dev = w1_search_master(data);
521         if (!dev) {
522                 printk(KERN_ERR "Failed to find w1 master device for data %08lx, it is impossible.\n",
523                                 data);
524                 return;
525         }
526
527         tmp = (struct w1_reg_num *) &rn;
528
529         slave_count = 0;
530         list_for_each(ent, &dev->slist) {
531
532                 sl = list_entry(ent, struct w1_slave, w1_slave_entry);
533
534                 if (sl->reg_num.family == tmp->family &&
535                     sl->reg_num.id == tmp->id &&
536                     sl->reg_num.crc == tmp->crc) {
537                         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
538                         break;
539                 } else if (sl->reg_num.family == tmp->family) {
540                         family_found = 1;
541                         break;
542                 }
543
544                 slave_count++;
545         }
546
547         rn = cpu_to_le64(rn);
548
549         if (slave_count == dev->slave_count &&
550                 rn && ((le64_to_cpu(rn) >> 56) & 0xff) == w1_calc_crc8((u8 *)&rn, 7)) {
551                 w1_attach_slave_device(dev, tmp);
552         }
553
554         atomic_dec(&dev->refcnt);
555 }
556
557 /**
558  * Performs a ROM Search & registers any devices found.
559  * The 1-wire search is a simple binary tree search.
560  * For each bit of the address, we read two bits and write one bit.
561  * The bit written will put to sleep all devies that don't match that bit.
562  * When the two reads differ, the direction choice is obvious.
563  * When both bits are 0, we must choose a path to take.
564  * When we can scan all 64 bits without having to choose a path, we are done.
565  *
566  * See "Application note 187 1-wire search algorithm" at www.maxim-ic.com
567  *
568  * @dev        The master device to search
569  * @cb         Function to call when a device is found
570  */
571 void w1_search(struct w1_master *dev, w1_slave_found_callback cb)
572 {
573         u64 last_rn, rn, tmp64;
574         int i, slave_count = 0;
575         int last_zero, last_device;
576         int search_bit, desc_bit;
577         u8  triplet_ret = 0;
578
579         search_bit = 0;
580         rn = last_rn = 0;
581         last_device = 0;
582         last_zero = -1;
583
584         desc_bit = 64;
585
586         while ( !last_device && (slave_count++ < dev->max_slave_count) ) {
587                 last_rn = rn;
588                 rn = 0;
589
590                 /*
591                  * Reset bus and all 1-wire device state machines
592                  * so they can respond to our requests.
593                  *
594                  * Return 0 - device(s) present, 1 - no devices present.
595                  */
596                 if (w1_reset_bus(dev)) {
597                         dev_info(&dev->dev, "No devices present on the wire.\n");
598                         break;
599                 }
600
601                 /* Start the search */
602                 w1_write_8(dev, W1_SEARCH);
603                 for (i = 0; i < 64; ++i) {
604                         /* Determine the direction/search bit */
605                         if (i == desc_bit)
606                                 search_bit = 1;   /* took the 0 path last time, so take the 1 path */
607                         else if (i > desc_bit)
608                                 search_bit = 0;   /* take the 0 path on the next branch */
609                         else
610                                 search_bit = ((last_rn >> i) & 0x1);
611
612                         /** Read two bits and write one bit */
613                         triplet_ret = w1_triplet(dev, search_bit);
614
615                         /* quit if no device responded */
616                         if ( (triplet_ret & 0x03) == 0x03 )
617                                 break;
618
619                         /* If both directions were valid, and we took the 0 path... */
620                         if (triplet_ret == 0)
621                                 last_zero = i;
622
623                         /* extract the direction taken & update the device number */
624                         tmp64 = (triplet_ret >> 2);
625                         rn |= (tmp64 << i);
626                 }
627
628                 if ( (triplet_ret & 0x03) != 0x03 ) {
629                         if ( (desc_bit == last_zero) || (last_zero < 0))
630                                 last_device = 1;
631                         desc_bit = last_zero;
632                         cb(dev->bus_master->data, rn);
633                 }
634         }
635 }
636
637 static int w1_control(void *data)
638 {
639         struct w1_slave *sl, *sln;
640         struct w1_master *dev, *n;
641         int err, have_to_wait = 0;
642
643         daemonize("w1_control");
644         allow_signal(SIGTERM);
645
646         while (!control_needs_exit || have_to_wait) {
647                 have_to_wait = 0;
648
649                 try_to_freeze();
650                 msleep_interruptible(w1_timeout * 1000);
651
652                 if (signal_pending(current))
653                         flush_signals(current);
654
655                 list_for_each_entry_safe(dev, n, &w1_masters, w1_master_entry) {
656                         if (!control_needs_exit && !dev->flags)
657                                 continue;
658                         /*
659                          * Little race: we can create thread but not set the flag.
660                          * Get a chance for external process to set flag up.
661                          */
662                         if (!dev->initialized) {
663                                 have_to_wait = 1;
664                                 continue;
665                         }
666
667                         if (control_needs_exit) {
668                                 set_bit(W1_MASTER_NEED_EXIT, &dev->flags);
669
670                                 err = kill_proc(dev->kpid, SIGTERM, 1);
671                                 if (err)
672                                         dev_err(&dev->dev,
673                                                  "Failed to send signal to w1 kernel thread %d.\n",
674                                                  dev->kpid);
675                         }
676
677                         if (test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
678                                 wait_for_completion(&dev->dev_exited);
679                                 spin_lock_bh(&w1_mlock);
680                                 list_del(&dev->w1_master_entry);
681                                 spin_unlock_bh(&w1_mlock);
682
683                                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
684                                         list_del(&sl->w1_slave_entry);
685
686                                         w1_slave_detach(sl);
687                                         kfree(sl);
688                                 }
689                                 w1_destroy_master_attributes(dev);
690                                 atomic_dec(&dev->refcnt);
691                                 continue;
692                         }
693
694                         if (test_bit(W1_MASTER_NEED_RECONNECT, &dev->flags)) {
695                                 dev_info(&dev->dev, "Reconnecting slaves in device %s.\n", dev->name);
696                                 down(&dev->mutex);
697                                 list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
698                                         if (sl->family->fid == W1_FAMILY_DEFAULT) {
699                                                 struct w1_reg_num rn;
700                                                 list_del(&sl->w1_slave_entry);
701                                                 w1_slave_detach(sl);
702
703                                                 memcpy(&rn, &sl->reg_num, sizeof(rn));
704
705                                                 kfree(sl);
706
707                                                 w1_attach_slave_device(dev, &rn);
708                                         }
709                                 }
710                                 clear_bit(W1_MASTER_NEED_RECONNECT, &dev->flags);
711                                 up(&dev->mutex);
712                         }
713                 }
714         }
715
716         complete_and_exit(&w1_control_complete, 0);
717 }
718
719 int w1_process(void *data)
720 {
721         struct w1_master *dev = (struct w1_master *) data;
722         struct w1_slave *sl, *sln;
723
724         daemonize("%s", dev->name);
725         allow_signal(SIGTERM);
726
727         while (!test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
728                 try_to_freeze();
729                 msleep_interruptible(w1_timeout * 1000);
730
731                 if (signal_pending(current))
732                         flush_signals(current);
733
734                 if (test_bit(W1_MASTER_NEED_EXIT, &dev->flags))
735                         break;
736
737                 if (!dev->initialized)
738                         continue;
739
740                 if (dev->search_count == 0)
741                         continue;
742
743                 if (down_interruptible(&dev->mutex))
744                         continue;
745
746                 list_for_each_entry(sl, &dev->slist, w1_slave_entry)
747                         clear_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
748
749                 w1_search_devices(dev, w1_slave_found);
750
751                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
752                         if (!test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags) && !--sl->ttl) {
753                                 list_del (&sl->w1_slave_entry);
754
755                                 w1_slave_detach (sl);
756                                 kfree (sl);
757
758                                 dev->slave_count--;
759                         } else if (test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags))
760                                 sl->ttl = dev->slave_ttl;
761                 }
762
763                 if (dev->search_count > 0)
764                         dev->search_count--;
765
766                 up(&dev->mutex);
767         }
768
769         atomic_dec(&dev->refcnt);
770         complete_and_exit(&dev->dev_exited, 0);
771
772         return 0;
773 }
774
775 static int w1_init(void)
776 {
777         int retval;
778
779         printk(KERN_INFO "Driver for 1-wire Dallas network protocol.\n");
780
781         retval = bus_register(&w1_bus_type);
782         if (retval) {
783                 printk(KERN_ERR "Failed to register bus. err=%d.\n", retval);
784                 goto err_out_exit_init;
785         }
786
787         retval = driver_register(&w1_driver);
788         if (retval) {
789                 printk(KERN_ERR
790                         "Failed to register master driver. err=%d.\n",
791                         retval);
792                 goto err_out_bus_unregister;
793         }
794
795         control_thread = kernel_thread(&w1_control, NULL, 0);
796         if (control_thread < 0) {
797                 printk(KERN_ERR "Failed to create control thread. err=%d\n",
798                         control_thread);
799                 retval = control_thread;
800                 goto err_out_driver_unregister;
801         }
802
803         return 0;
804
805 err_out_driver_unregister:
806         driver_unregister(&w1_driver);
807
808 err_out_bus_unregister:
809         bus_unregister(&w1_bus_type);
810
811 err_out_exit_init:
812         return retval;
813 }
814
815 static void w1_fini(void)
816 {
817         struct w1_master *dev;
818
819         list_for_each_entry(dev, &w1_masters, w1_master_entry)
820                 __w1_remove_master_device(dev);
821
822         control_needs_exit = 1;
823         wait_for_completion(&w1_control_complete);
824
825         driver_unregister(&w1_driver);
826         bus_unregister(&w1_bus_type);
827 }
828
829 module_init(w1_init);
830 module_exit(w1_fini);