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