e592ca2edd494bf14fb39778e62f2abdbf3cf6e2
[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 = dev_to_w1_master(dev);
80         complete(&md->dev_released);
81 }
82
83 static void w1_slave_release(struct device *dev)
84 {
85         struct w1_slave *sl = dev_to_w1_slave(dev);
86         complete(&sl->dev_released);
87 }
88
89 static ssize_t w1_slave_read_name(struct device *dev, struct device_attribute *attr, char *buf)
90 {
91       struct w1_slave *sl = dev_to_w1_slave(dev);
92
93       return sprintf(buf, "%s\n", sl->name);
94 }
95
96 static ssize_t w1_slave_read_id(struct kobject *kobj, char *buf, loff_t off, size_t count)
97 {
98       struct w1_slave *sl = kobj_to_w1_slave(kobj);
99
100       atomic_inc(&sl->refcnt);
101       if (off > 8) {
102               count = 0;
103         } else {
104                 if (off + count > 8)
105                         count = 8 - off;
106
107                 memcpy(buf, (u8 *)&sl->reg_num, count);
108         }
109         atomic_dec(&sl->refcnt);
110
111         return count;
112   }
113
114 static struct device_attribute w1_slave_attr_name =
115         __ATTR(name, S_IRUGO, w1_slave_read_name, NULL);
116
117 static struct bin_attribute w1_slave_attr_bin_id = {
118       .attr = {
119               .name = "id",
120               .mode = S_IRUGO,
121               .owner = THIS_MODULE,
122       },
123       .size = 8,
124       .read = w1_slave_read_id,
125 };
126
127 /* Default family */
128 static struct w1_family w1_default_family;
129
130 static int w1_hotplug(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size);
131
132 static struct bus_type w1_bus_type = {
133         .name = "w1",
134         .match = w1_master_match,
135         .hotplug = w1_hotplug,
136 };
137
138 struct device_driver w1_master_driver = {
139         .name = "w1_master_driver",
140         .bus = &w1_bus_type,
141         .probe = w1_master_probe,
142         .remove = w1_master_remove,
143 };
144
145 struct device w1_master_device = {
146         .parent = NULL,
147         .bus = &w1_bus_type,
148         .bus_id = "w1 bus master",
149         .driver = &w1_master_driver,
150         .release = &w1_master_release
151 };
152
153 struct device_driver w1_slave_driver = {
154         .name = "w1_slave_driver",
155         .bus = &w1_bus_type,
156 };
157
158 struct device w1_slave_device = {
159         .parent = NULL,
160         .bus = &w1_bus_type,
161         .bus_id = "w1 bus slave",
162         .driver = &w1_slave_driver,
163 };
164
165 static ssize_t w1_master_attribute_show_name(struct device *dev, struct device_attribute *attr, char *buf)
166 {
167         struct w1_master *md = dev_to_w1_master(dev);
168         ssize_t count;
169
170         if (down_interruptible (&md->mutex))
171                 return -EBUSY;
172
173         count = sprintf(buf, "%s\n", md->name);
174
175         up(&md->mutex);
176
177         return count;
178 }
179
180 static ssize_t w1_master_attribute_store_search(struct device * dev,
181                                                 struct device_attribute *attr,
182                                                 const char * buf, size_t count)
183 {
184         struct w1_master *md = dev_to_w1_master(dev);
185
186         if (down_interruptible (&md->mutex))
187                 return -EBUSY;
188
189         md->search_count = simple_strtol(buf, NULL, 0);
190
191         up(&md->mutex);
192
193         return count;
194 }
195
196 static ssize_t w1_master_attribute_show_search(struct device *dev,
197                                                struct device_attribute *attr,
198                                                char *buf)
199 {
200         struct w1_master *md = dev_to_w1_master(dev);
201         ssize_t count;
202
203         if (down_interruptible (&md->mutex))
204                 return -EBUSY;
205
206         count = sprintf(buf, "%d\n", md->search_count);
207
208         up(&md->mutex);
209
210         return count;
211 }
212
213 static ssize_t w1_master_attribute_show_pointer(struct device *dev, struct device_attribute *attr, char *buf)
214 {
215         struct w1_master *md = dev_to_w1_master(dev);
216         ssize_t count;
217
218         if (down_interruptible(&md->mutex))
219                 return -EBUSY;
220
221         count = sprintf(buf, "0x%p\n", md->bus_master);
222
223         up(&md->mutex);
224         return count;
225 }
226
227 static ssize_t w1_master_attribute_show_timeout(struct device *dev, struct device_attribute *attr, char *buf)
228 {
229         ssize_t count;
230         count = sprintf(buf, "%d\n", w1_timeout);
231         return count;
232 }
233
234 static ssize_t w1_master_attribute_show_max_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
235 {
236         struct w1_master *md = dev_to_w1_master(dev);
237         ssize_t count;
238
239         if (down_interruptible(&md->mutex))
240                 return -EBUSY;
241
242         count = sprintf(buf, "%d\n", md->max_slave_count);
243
244         up(&md->mutex);
245         return count;
246 }
247
248 static ssize_t w1_master_attribute_show_attempts(struct device *dev, struct device_attribute *attr, char *buf)
249 {
250         struct w1_master *md = dev_to_w1_master(dev);
251         ssize_t count;
252
253         if (down_interruptible(&md->mutex))
254                 return -EBUSY;
255
256         count = sprintf(buf, "%lu\n", md->attempts);
257
258         up(&md->mutex);
259         return count;
260 }
261
262 static ssize_t w1_master_attribute_show_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
263 {
264         struct w1_master *md = dev_to_w1_master(dev);
265         ssize_t count;
266
267         if (down_interruptible(&md->mutex))
268                 return -EBUSY;
269
270         count = sprintf(buf, "%d\n", md->slave_count);
271
272         up(&md->mutex);
273         return count;
274 }
275
276 static ssize_t w1_master_attribute_show_slaves(struct device *dev, struct device_attribute *attr, char *buf)
277 {
278         struct w1_master *md = dev_to_w1_master(dev);
279         int c = PAGE_SIZE;
280
281         if (down_interruptible(&md->mutex))
282                 return -EBUSY;
283
284         if (md->slave_count == 0)
285                 c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n");
286         else {
287                 struct list_head *ent, *n;
288                 struct w1_slave *sl;
289
290                 list_for_each_safe(ent, n, &md->slist) {
291                         sl = list_entry(ent, struct w1_slave, w1_slave_entry);
292
293                         c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", sl->name);
294                 }
295         }
296
297         up(&md->mutex);
298
299         return PAGE_SIZE - c;
300 }
301
302 #define W1_MASTER_ATTR_RO(_name, _mode)                         \
303         struct device_attribute w1_master_attribute_##_name =   \
304                 __ATTR(w1_master_##_name, _mode,                \
305                        w1_master_attribute_show_##_name, NULL)
306
307 #define W1_MASTER_ATTR_RW(_name, _mode)                         \
308         struct device_attribute w1_master_attribute_##_name =   \
309                 __ATTR(w1_master_##_name, _mode,                \
310                        w1_master_attribute_show_##_name,        \
311                        w1_master_attribute_store_##_name)
312
313 static W1_MASTER_ATTR_RO(name, S_IRUGO);
314 static W1_MASTER_ATTR_RO(slaves, S_IRUGO);
315 static W1_MASTER_ATTR_RO(slave_count, S_IRUGO);
316 static W1_MASTER_ATTR_RO(max_slave_count, S_IRUGO);
317 static W1_MASTER_ATTR_RO(attempts, S_IRUGO);
318 static W1_MASTER_ATTR_RO(timeout, S_IRUGO);
319 static W1_MASTER_ATTR_RO(pointer, S_IRUGO);
320 static W1_MASTER_ATTR_RW(search, S_IRUGO | S_IWUGO);
321
322 static struct attribute *w1_master_default_attrs[] = {
323         &w1_master_attribute_name.attr,
324         &w1_master_attribute_slaves.attr,
325         &w1_master_attribute_slave_count.attr,
326         &w1_master_attribute_max_slave_count.attr,
327         &w1_master_attribute_attempts.attr,
328         &w1_master_attribute_timeout.attr,
329         &w1_master_attribute_pointer.attr,
330         &w1_master_attribute_search.attr,
331         NULL
332 };
333
334 static struct attribute_group w1_master_defattr_group = {
335         .attrs = w1_master_default_attrs,
336 };
337
338 int w1_create_master_attributes(struct w1_master *master)
339 {
340         return sysfs_create_group(&master->dev.kobj, &w1_master_defattr_group);
341 }
342
343 void w1_destroy_master_attributes(struct w1_master *master)
344 {
345         sysfs_remove_group(&master->dev.kobj, &w1_master_defattr_group);
346 }
347
348 #ifdef CONFIG_HOTPLUG
349 static int w1_hotplug(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size)
350 {
351         struct w1_master *md = NULL;
352         struct w1_slave *sl = NULL;
353         char *event_owner, *name;
354         int err, cur_index=0, cur_len=0;
355
356         if (dev->driver == &w1_master_driver) {
357                 md = container_of(dev, struct w1_master, dev);
358                 event_owner = "master";
359                 name = md->name;
360         } else if (dev->driver == &w1_slave_driver) {
361                 sl = container_of(dev, struct w1_slave, dev);
362                 event_owner = "slave";
363                 name = sl->name;
364         } else {
365                 dev_dbg(dev, "Unknown hotplug event.\n");
366                 return -EINVAL;
367         }
368
369         dev_dbg(dev, "Hotplug event for %s %s, bus_id=%s.\n", event_owner, name, dev->bus_id);
370
371         if (dev->driver != &w1_slave_driver || !sl)
372                 return 0;
373
374         err = add_hotplug_env_var(envp, num_envp, &cur_index, buffer, buffer_size, &cur_len, "W1_FID=%02X", sl->reg_num.family);
375         if (err)
376                 return err;
377
378         err = add_hotplug_env_var(envp, num_envp, &cur_index, buffer, buffer_size, &cur_len, "W1_SLAVE_ID=%024LX", (u64)sl->reg_num.id);
379         if (err)
380                 return err;
381
382         return 0;
383 };
384 #else
385 static int w1_hotplug(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size)
386 {
387         return 0;
388 }
389 #endif
390
391 static int __w1_attach_slave_device(struct w1_slave *sl)
392 {
393         int err;
394
395         sl->dev.parent = &sl->master->dev;
396         sl->dev.driver = &w1_slave_driver;
397         sl->dev.bus = &w1_bus_type;
398         sl->dev.release = &w1_slave_release;
399
400         snprintf(&sl->dev.bus_id[0], sizeof(sl->dev.bus_id),
401                  "%02x-%012llx",
402                  (unsigned int) sl->reg_num.family,
403                  (unsigned long long) sl->reg_num.id);
404         snprintf(&sl->name[0], sizeof(sl->name),
405                  "%02x-%012llx",
406                  (unsigned int) sl->reg_num.family,
407                  (unsigned long long) sl->reg_num.id);
408
409         dev_dbg(&sl->dev, "%s: registering %s.\n", __func__,
410                 &sl->dev.bus_id[0]);
411
412         err = device_register(&sl->dev);
413         if (err < 0) {
414                 dev_err(&sl->dev,
415                         "Device registration [%s] failed. err=%d\n",
416                         sl->dev.bus_id, err);
417                 return err;
418         }
419
420         /* Create "name" entry */
421         err = device_create_file(&sl->dev, &w1_slave_attr_name);
422         if (err < 0) {
423                 dev_err(&sl->dev,
424                         "sysfs file creation for [%s] failed. err=%d\n",
425                         sl->dev.bus_id, err);
426                 goto out_unreg;
427         }
428
429         /* Create "id" entry */
430         err = sysfs_create_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
431         if (err < 0) {
432                 dev_err(&sl->dev,
433                         "sysfs file creation for [%s] failed. err=%d\n",
434                         sl->dev.bus_id, err);
435                 goto out_rem1;
436         }
437
438         /* if the family driver needs to initialize something... */
439         if (sl->family->fops && sl->family->fops->add_slave &&
440             ((err = sl->family->fops->add_slave(sl)) < 0)) {
441                 dev_err(&sl->dev,
442                         "sysfs file creation for [%s] failed. err=%d\n",
443                         sl->dev.bus_id, err);
444                 goto out_rem2;
445         }
446
447         list_add_tail(&sl->w1_slave_entry, &sl->master->slist);
448
449         return 0;
450
451 out_rem2:
452         sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
453 out_rem1:
454         device_remove_file(&sl->dev, &w1_slave_attr_name);
455 out_unreg:
456         device_unregister(&sl->dev);
457         return err;
458 }
459
460 static int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
461 {
462         struct w1_slave *sl;
463         struct w1_family *f;
464         int err;
465         struct w1_netlink_msg msg;
466
467         sl = kmalloc(sizeof(struct w1_slave), GFP_KERNEL);
468         if (!sl) {
469                 dev_err(&dev->dev,
470                          "%s: failed to allocate new slave device.\n",
471                          __func__);
472                 return -ENOMEM;
473         }
474
475         memset(sl, 0, sizeof(*sl));
476
477         sl->owner = THIS_MODULE;
478         sl->master = dev;
479         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
480
481         memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));
482         atomic_set(&sl->refcnt, 0);
483         init_completion(&sl->dev_released);
484
485         spin_lock(&w1_flock);
486         f = w1_family_registered(rn->family);
487         if (!f) {
488                 f= &w1_default_family;
489                 dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n",
490                           rn->family, rn->family,
491                           (unsigned long long)rn->id, rn->crc);
492         }
493         __w1_family_get(f);
494         spin_unlock(&w1_flock);
495
496         sl->family = f;
497
498
499         err = __w1_attach_slave_device(sl);
500         if (err < 0) {
501                 dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__,
502                          sl->name);
503                 w1_family_put(sl->family);
504                 kfree(sl);
505                 return err;
506         }
507
508         sl->ttl = dev->slave_ttl;
509         dev->slave_count++;
510
511         memcpy(&msg.id.id, rn, sizeof(msg.id.id));
512         msg.type = W1_SLAVE_ADD;
513         w1_netlink_send(dev, &msg);
514
515         return 0;
516 }
517
518 static void w1_slave_detach(struct w1_slave *sl)
519 {
520         struct w1_netlink_msg msg;
521
522         dev_info(&sl->dev, "%s: detaching %s.\n", __func__, sl->name);
523
524         while (atomic_read(&sl->refcnt)) {
525                 printk(KERN_INFO "Waiting for %s to become free: refcnt=%d.\n",
526                                 sl->name, atomic_read(&sl->refcnt));
527
528                 if (msleep_interruptible(1000))
529                         flush_signals(current);
530         }
531
532         if (sl->family->fops && sl->family->fops->remove_slave)
533                 sl->family->fops->remove_slave(sl);
534
535         sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
536         device_remove_file(&sl->dev, &w1_slave_attr_name);
537         device_unregister(&sl->dev);
538         w1_family_put(sl->family);
539
540         sl->master->slave_count--;
541
542         memcpy(&msg.id.id, &sl->reg_num, sizeof(msg.id.id));
543         msg.type = W1_SLAVE_REMOVE;
544         w1_netlink_send(sl->master, &msg);
545 }
546
547 static struct w1_master *w1_search_master(unsigned long data)
548 {
549         struct w1_master *dev;
550         int found = 0;
551
552         spin_lock_bh(&w1_mlock);
553         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
554                 if (dev->bus_master->data == data) {
555                         found = 1;
556                         atomic_inc(&dev->refcnt);
557                         break;
558                 }
559         }
560         spin_unlock_bh(&w1_mlock);
561
562         return (found)?dev:NULL;
563 }
564
565 void w1_reconnect_slaves(struct w1_family *f)
566 {
567         struct w1_master *dev;
568
569         spin_lock_bh(&w1_mlock);
570         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
571                 dev_info(&dev->dev, "Reconnecting slaves in %s into new family %02x.\n",
572                                 dev->name, f->fid);
573                 set_bit(W1_MASTER_NEED_RECONNECT, &dev->flags);
574         }
575         spin_unlock_bh(&w1_mlock);
576 }
577
578 static void w1_slave_found(unsigned long data, u64 rn)
579 {
580         int slave_count;
581         struct w1_slave *sl;
582         struct list_head *ent;
583         struct w1_reg_num *tmp;
584         int family_found = 0;
585         struct w1_master *dev;
586         u64 rn_le = cpu_to_le64(rn);
587
588         dev = w1_search_master(data);
589         if (!dev) {
590                 printk(KERN_ERR "Failed to find w1 master device for data %08lx, it is impossible.\n",
591                                 data);
592                 return;
593         }
594
595         tmp = (struct w1_reg_num *) &rn;
596
597         slave_count = 0;
598         list_for_each(ent, &dev->slist) {
599
600                 sl = list_entry(ent, struct w1_slave, w1_slave_entry);
601
602                 if (sl->reg_num.family == tmp->family &&
603                     sl->reg_num.id == tmp->id &&
604                     sl->reg_num.crc == tmp->crc) {
605                         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
606                         break;
607                 } else if (sl->reg_num.family == tmp->family) {
608                         family_found = 1;
609                         break;
610                 }
611
612                 slave_count++;
613         }
614
615         if (slave_count == dev->slave_count &&
616                 rn && ((rn >> 56) & 0xff) == w1_calc_crc8((u8 *)&rn_le, 7)) {
617                 w1_attach_slave_device(dev, tmp);
618         }
619
620         atomic_dec(&dev->refcnt);
621 }
622
623 /**
624  * Performs a ROM Search & registers any devices found.
625  * The 1-wire search is a simple binary tree search.
626  * For each bit of the address, we read two bits and write one bit.
627  * The bit written will put to sleep all devies that don't match that bit.
628  * When the two reads differ, the direction choice is obvious.
629  * When both bits are 0, we must choose a path to take.
630  * When we can scan all 64 bits without having to choose a path, we are done.
631  *
632  * See "Application note 187 1-wire search algorithm" at www.maxim-ic.com
633  *
634  * @dev        The master device to search
635  * @cb         Function to call when a device is found
636  */
637 void w1_search(struct w1_master *dev, w1_slave_found_callback cb)
638 {
639         u64 last_rn, rn, tmp64;
640         int i, slave_count = 0;
641         int last_zero, last_device;
642         int search_bit, desc_bit;
643         u8  triplet_ret = 0;
644
645         search_bit = 0;
646         rn = last_rn = 0;
647         last_device = 0;
648         last_zero = -1;
649
650         desc_bit = 64;
651
652         while ( !last_device && (slave_count++ < dev->max_slave_count) ) {
653                 last_rn = rn;
654                 rn = 0;
655
656                 /*
657                  * Reset bus and all 1-wire device state machines
658                  * so they can respond to our requests.
659                  *
660                  * Return 0 - device(s) present, 1 - no devices present.
661                  */
662                 if (w1_reset_bus(dev)) {
663                         dev_dbg(&dev->dev, "No devices present on the wire.\n");
664                         break;
665                 }
666
667                 /* Start the search */
668                 w1_write_8(dev, W1_SEARCH);
669                 for (i = 0; i < 64; ++i) {
670                         /* Determine the direction/search bit */
671                         if (i == desc_bit)
672                                 search_bit = 1;   /* took the 0 path last time, so take the 1 path */
673                         else if (i > desc_bit)
674                                 search_bit = 0;   /* take the 0 path on the next branch */
675                         else
676                                 search_bit = ((last_rn >> i) & 0x1);
677
678                         /** Read two bits and write one bit */
679                         triplet_ret = w1_triplet(dev, search_bit);
680
681                         /* quit if no device responded */
682                         if ( (triplet_ret & 0x03) == 0x03 )
683                                 break;
684
685                         /* If both directions were valid, and we took the 0 path... */
686                         if (triplet_ret == 0)
687                                 last_zero = i;
688
689                         /* extract the direction taken & update the device number */
690                         tmp64 = (triplet_ret >> 2);
691                         rn |= (tmp64 << i);
692                 }
693
694                 if ( (triplet_ret & 0x03) != 0x03 ) {
695                         if ( (desc_bit == last_zero) || (last_zero < 0))
696                                 last_device = 1;
697                         desc_bit = last_zero;
698                         cb(dev->bus_master->data, rn);
699                 }
700         }
701 }
702
703 static int w1_control(void *data)
704 {
705         struct w1_slave *sl, *sln;
706         struct w1_master *dev, *n;
707         int err, have_to_wait = 0;
708
709         daemonize("w1_control");
710         allow_signal(SIGTERM);
711
712         while (!control_needs_exit || have_to_wait) {
713                 have_to_wait = 0;
714
715                 try_to_freeze();
716                 msleep_interruptible(w1_timeout * 1000);
717
718                 if (signal_pending(current))
719                         flush_signals(current);
720
721                 list_for_each_entry_safe(dev, n, &w1_masters, w1_master_entry) {
722                         if (!control_needs_exit && !dev->flags)
723                                 continue;
724                         /*
725                          * Little race: we can create thread but not set the flag.
726                          * Get a chance for external process to set flag up.
727                          */
728                         if (!dev->initialized) {
729                                 have_to_wait = 1;
730                                 continue;
731                         }
732
733                         if (control_needs_exit) {
734                                 set_bit(W1_MASTER_NEED_EXIT, &dev->flags);
735
736                                 err = kill_proc(dev->kpid, SIGTERM, 1);
737                                 if (err)
738                                         dev_err(&dev->dev,
739                                                  "Failed to send signal to w1 kernel thread %d.\n",
740                                                  dev->kpid);
741                         }
742
743                         if (test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
744                                 wait_for_completion(&dev->dev_exited);
745                                 spin_lock_bh(&w1_mlock);
746                                 list_del(&dev->w1_master_entry);
747                                 spin_unlock_bh(&w1_mlock);
748
749                                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
750                                         list_del(&sl->w1_slave_entry);
751
752                                         w1_slave_detach(sl);
753                                         kfree(sl);
754                                 }
755                                 w1_destroy_master_attributes(dev);
756                                 atomic_dec(&dev->refcnt);
757                                 continue;
758                         }
759
760                         if (test_bit(W1_MASTER_NEED_RECONNECT, &dev->flags)) {
761                                 dev_info(&dev->dev, "Reconnecting slaves in device %s.\n", dev->name);
762                                 down(&dev->mutex);
763                                 list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
764                                         if (sl->family->fid == W1_FAMILY_DEFAULT) {
765                                                 struct w1_reg_num rn;
766                                                 list_del(&sl->w1_slave_entry);
767                                                 w1_slave_detach(sl);
768
769                                                 memcpy(&rn, &sl->reg_num, sizeof(rn));
770
771                                                 kfree(sl);
772
773                                                 w1_attach_slave_device(dev, &rn);
774                                         }
775                                 }
776                                 clear_bit(W1_MASTER_NEED_RECONNECT, &dev->flags);
777                                 up(&dev->mutex);
778                         }
779                 }
780         }
781
782         complete_and_exit(&w1_control_complete, 0);
783 }
784
785 int w1_process(void *data)
786 {
787         struct w1_master *dev = (struct w1_master *) data;
788         struct w1_slave *sl, *sln;
789
790         daemonize("%s", dev->name);
791         allow_signal(SIGTERM);
792
793         while (!test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
794                 try_to_freeze();
795                 msleep_interruptible(w1_timeout * 1000);
796
797                 if (signal_pending(current))
798                         flush_signals(current);
799
800                 if (test_bit(W1_MASTER_NEED_EXIT, &dev->flags))
801                         break;
802
803                 if (!dev->initialized)
804                         continue;
805
806                 if (dev->search_count == 0)
807                         continue;
808
809                 if (down_interruptible(&dev->mutex))
810                         continue;
811
812                 list_for_each_entry(sl, &dev->slist, w1_slave_entry)
813                         clear_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
814
815                 w1_search_devices(dev, w1_slave_found);
816
817                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
818                         if (!test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags) && !--sl->ttl) {
819                                 list_del (&sl->w1_slave_entry);
820
821                                 w1_slave_detach(sl);
822                                 kfree(sl);
823
824                                 dev->slave_count--;
825                         } else if (test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags))
826                                 sl->ttl = dev->slave_ttl;
827                 }
828
829                 if (dev->search_count > 0)
830                         dev->search_count--;
831
832                 up(&dev->mutex);
833         }
834
835         atomic_dec(&dev->refcnt);
836         complete_and_exit(&dev->dev_exited, 0);
837
838         return 0;
839 }
840
841 static int w1_init(void)
842 {
843         int retval;
844
845         printk(KERN_INFO "Driver for 1-wire Dallas network protocol.\n");
846
847         retval = bus_register(&w1_bus_type);
848         if (retval) {
849                 printk(KERN_ERR "Failed to register bus. err=%d.\n", retval);
850                 goto err_out_exit_init;
851         }
852
853         retval = driver_register(&w1_master_driver);
854         if (retval) {
855                 printk(KERN_ERR
856                         "Failed to register master driver. err=%d.\n",
857                         retval);
858                 goto err_out_bus_unregister;
859         }
860
861         retval = driver_register(&w1_slave_driver);
862         if (retval) {
863                 printk(KERN_ERR
864                         "Failed to register master driver. err=%d.\n",
865                         retval);
866                 goto err_out_master_unregister;
867         }
868
869         control_thread = kernel_thread(&w1_control, NULL, 0);
870         if (control_thread < 0) {
871                 printk(KERN_ERR "Failed to create control thread. err=%d\n",
872                         control_thread);
873                 retval = control_thread;
874                 goto err_out_slave_unregister;
875         }
876
877         return 0;
878
879 err_out_slave_unregister:
880         driver_unregister(&w1_slave_driver);
881
882 err_out_master_unregister:
883         driver_unregister(&w1_master_driver);
884
885 err_out_bus_unregister:
886         bus_unregister(&w1_bus_type);
887
888 err_out_exit_init:
889         return retval;
890 }
891
892 static void w1_fini(void)
893 {
894         struct w1_master *dev;
895
896         list_for_each_entry(dev, &w1_masters, w1_master_entry)
897                 __w1_remove_master_device(dev);
898
899         control_needs_exit = 1;
900         wait_for_completion(&w1_control_complete);
901
902         driver_unregister(&w1_slave_driver);
903         driver_unregister(&w1_master_driver);
904         bus_unregister(&w1_bus_type);
905 }
906
907 module_init(w1_init);
908 module_exit(w1_fini);