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_show_pointer(struct device *dev, struct device_attribute *attr, char *buf)
 152 {
 153         struct w1_master *md = container_of(dev, struct w1_master, dev);
 154         ssize_t count;
 155
 156         if (down_interruptible(&md->mutex))
 157                 return -EBUSY;
 158
 159         count = sprintf(buf, "0x%p\n", md->bus_master);
 160
 161         up(&md->mutex);
 162         return count;
 163 }
 164
 165 static ssize_t w1_master_attribute_show_timeout(struct device *dev, struct device_attribute *attr, char *buf)
 166 {
 167         ssize_t count;
 168         count = sprintf(buf, "%d\n", w1_timeout);
 169         return count;
 170 }
 171
 172 static ssize_t w1_master_attribute_show_max_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
 173 {
 174         struct w1_master *md = container_of(dev, struct w1_master, dev);
 175         ssize_t count;
 176
 177         if (down_interruptible(&md->mutex))
 178                 return -EBUSY;
 179
 180         count = sprintf(buf, "%d\n", md->max_slave_count);
 181
 182         up(&md->mutex);
 183         return count;
 184 }
 185
 186 static ssize_t w1_master_attribute_show_attempts(struct device *dev, struct device_attribute *attr, char *buf)
 187 {
 188         struct w1_master *md = container_of(dev, struct w1_master, dev);
 189         ssize_t count;
 190
 191         if (down_interruptible(&md->mutex))
 192                 return -EBUSY;
 193
 194         count = sprintf(buf, "%lu\n", md->attempts);
 195
 196         up(&md->mutex);
 197         return count;
 198 }
 199
 200 static ssize_t w1_master_attribute_show_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
 201 {
 202         struct w1_master *md = container_of(dev, struct w1_master, dev);
 203         ssize_t count;
 204
 205         if (down_interruptible(&md->mutex))
 206                 return -EBUSY;
 207
 208         count = sprintf(buf, "%d\n", md->slave_count);
 209
 210         up(&md->mutex);
 211         return count;
 212 }
 213
 214 static ssize_t w1_master_attribute_show_slaves(struct device *dev, struct device_attribute *attr, char *buf)
 215
 216 {
 217         struct w1_master *md = container_of(dev, struct w1_master, dev);
 218         int c = PAGE_SIZE;
 219
 220         if (down_interruptible(&md->mutex))
 221                 return -EBUSY;
 222
 223         if (md->slave_count == 0)
 224                 c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n");
 225         else {
 226                 struct list_head *ent, *n;
 227                 struct w1_slave *sl;
 228
 229                 list_for_each_safe(ent, n, &md->slist) {
 230                         sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 231
 232                         c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", sl->name);
 233                 }
 234         }
 235
 236         up(&md->mutex);
 237
 238         return PAGE_SIZE - c;
 239 }
 240
 241 #define W1_MASTER_ATTR_RO(_name, _mode)                         \
 242         struct device_attribute w1_master_attribute_##_name =   \
 243                 __ATTR(w1_master_##_name, _mode,                \
 244                        w1_master_attribute_show_##_name, NULL)
 245
 246 static W1_MASTER_ATTR_RO(name, S_IRUGO);
 247 static W1_MASTER_ATTR_RO(slaves, S_IRUGO);
 248 static W1_MASTER_ATTR_RO(slave_count, S_IRUGO);
 249 static W1_MASTER_ATTR_RO(max_slave_count, S_IRUGO);
 250 static W1_MASTER_ATTR_RO(attempts, S_IRUGO);
 251 static W1_MASTER_ATTR_RO(timeout, S_IRUGO);
 252 static W1_MASTER_ATTR_RO(pointer, S_IRUGO);
 253
 254 static struct attribute *w1_master_default_attrs[] = {
 255         &w1_master_attribute_name.attr,
 256         &w1_master_attribute_slaves.attr,
 257         &w1_master_attribute_slave_count.attr,
 258         &w1_master_attribute_max_slave_count.attr,
 259         &w1_master_attribute_attempts.attr,
 260         &w1_master_attribute_timeout.attr,
 261         &w1_master_attribute_pointer.attr,
 262         NULL
 263 };
 264
 265 static struct attribute_group w1_master_defattr_group = {
 266         .attrs = w1_master_default_attrs,
 267 };
 268
 269 int w1_create_master_attributes(struct w1_master *master)
 270 {
 271         return sysfs_create_group(&master->dev.kobj, &w1_master_defattr_group);
 272 }
 273
 274 void w1_destroy_master_attributes(struct w1_master *master)
 275 {
 276         sysfs_remove_group(&master->dev.kobj, &w1_master_defattr_group);
 277 }
 278
 279 static int __w1_attach_slave_device(struct w1_slave *sl)
 280 {
 281         int err;
 282
 283         sl->dev.parent = &sl->master->dev;
 284         sl->dev.driver = sl->master->driver;
 285         sl->dev.bus = &w1_bus_type;
 286         sl->dev.release = &w1_slave_release;
 287
 288         snprintf(&sl->dev.bus_id[0], sizeof(sl->dev.bus_id),
 289                   "%02x-%012llx",
 290                   (unsigned int) sl->reg_num.family,
 291                   (unsigned long long) sl->reg_num.id);
 292         snprintf (&sl->name[0], sizeof(sl->name),
 293                   "%02x-%012llx",
 294                   (unsigned int) sl->reg_num.family,
 295                   (unsigned long long) sl->reg_num.id);
 296
 297         dev_dbg(&sl->dev, "%s: registering %s.\n", __func__,
 298                 &sl->dev.bus_id[0]);
 299
 300         err = device_register(&sl->dev);
 301         if (err < 0) {
 302                 dev_err(&sl->dev,
 303                          "Device registration [%s] failed. err=%d\n",
 304                          sl->dev.bus_id, err);
 305                 return err;
 306         }
 307
 308         memcpy(&sl->attr_bin, &w1_slave_bin_attribute, sizeof(sl->attr_bin));
 309         memcpy(&sl->attr_name, &w1_slave_attribute, sizeof(sl->attr_name));
 310
 311         sl->attr_bin.read = sl->family->fops->rbin;
 312         sl->attr_name.show = sl->family->fops->rname;
 313
 314         err = device_create_file(&sl->dev, &sl->attr_name);
 315         if (err < 0) {
 316                 dev_err(&sl->dev,
 317                          "sysfs file creation for [%s] failed. err=%d\n",
 318                          sl->dev.bus_id, err);
 319                 device_unregister(&sl->dev);
 320                 return err;
 321         }
 322
 323         err = sysfs_create_bin_file(&sl->dev.kobj, &sl->attr_bin);
 324         if (err < 0) {
 325                 dev_err(&sl->dev,
 326                          "sysfs file creation for [%s] failed. err=%d\n",
 327                          sl->dev.bus_id, err);
 328                 device_remove_file(&sl->dev, &sl->attr_name);
 329                 device_unregister(&sl->dev);
 330                 return err;
 331         }
 332
 333         list_add_tail(&sl->w1_slave_entry, &sl->master->slist);
 334
 335         return 0;
 336 }
 337
 338 static int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
 339 {
 340         struct w1_slave *sl;
 341         struct w1_family *f;
 342         int err;
 343         struct w1_netlink_msg msg;
 344
 345         sl = kmalloc(sizeof(struct w1_slave), GFP_KERNEL);
 346         if (!sl) {
 347                 dev_err(&dev->dev,
 348                          "%s: failed to allocate new slave device.\n",
 349                          __func__);
 350                 return -ENOMEM;
 351         }
 352
 353         memset(sl, 0, sizeof(*sl));
 354
 355         sl->owner = THIS_MODULE;
 356         sl->master = dev;
 357         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 358
 359         memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));
 360         atomic_set(&sl->refcnt, 0);
 361         init_completion(&sl->dev_released);
 362
 363         spin_lock(&w1_flock);
 364         f = w1_family_registered(rn->family);
 365         if (!f) {
 366                 spin_unlock(&w1_flock);
 367                 dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n",
 368                           rn->family, rn->family,
 369                           (unsigned long long)rn->id, rn->crc);
 370                 kfree(sl);
 371                 return -ENODEV;
 372         }
 373         __w1_family_get(f);
 374         spin_unlock(&w1_flock);
 375
 376         sl->family = f;
 377
 378
 379         err = __w1_attach_slave_device(sl);
 380         if (err < 0) {
 381                 dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__,
 382                          sl->name);
 383                 w1_family_put(sl->family);
 384                 kfree(sl);
 385                 return err;
 386         }
 387
 388         sl->ttl = dev->slave_ttl;
 389         dev->slave_count++;
 390
 391         memcpy(&msg.id.id, rn, sizeof(msg.id.id));
 392         msg.type = W1_SLAVE_ADD;
 393         w1_netlink_send(dev, &msg);
 394
 395         return 0;
 396 }
 397
 398 static void w1_slave_detach(struct w1_slave *sl)
 399 {
 400         struct w1_netlink_msg msg;
 401
 402         dev_info(&sl->dev, "%s: detaching %s.\n", __func__, sl->name);
 403
 404         while (atomic_read(&sl->refcnt)) {
 405                 printk(KERN_INFO "Waiting for %s to become free: refcnt=%d.\n",
 406                                 sl->name, atomic_read(&sl->refcnt));
 407
 408                 if (msleep_interruptible(1000))
 409                         flush_signals(current);
 410         }
 411
 412         sysfs_remove_bin_file (&sl->dev.kobj, &sl->attr_bin);
 413         device_remove_file(&sl->dev, &sl->attr_name);
 414         device_unregister(&sl->dev);
 415         w1_family_put(sl->family);
 416
 417         memcpy(&msg.id.id, &sl->reg_num, sizeof(msg.id.id));
 418         msg.type = W1_SLAVE_REMOVE;
 419         w1_netlink_send(sl->master, &msg);
 420 }
 421
 422 static struct w1_master *w1_search_master(unsigned long data)
 423 {
 424         struct w1_master *dev;
 425         int found = 0;
 426
 427         spin_lock_bh(&w1_mlock);
 428         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 429                 if (dev->bus_master->data == data) {
 430                         found = 1;
 431                         atomic_inc(&dev->refcnt);
 432                         break;
 433                 }
 434         }
 435         spin_unlock_bh(&w1_mlock);
 436
 437         return (found)?dev:NULL;
 438 }
 439
 440 static void w1_slave_found(unsigned long data, u64 rn)
 441 {
 442         int slave_count;
 443         struct w1_slave *sl;
 444         struct list_head *ent;
 445         struct w1_reg_num *tmp;
 446         int family_found = 0;
 447         struct w1_master *dev;
 448
 449         dev = w1_search_master(data);
 450         if (!dev) {
 451                 printk(KERN_ERR "Failed to find w1 master device for data %08lx, it is impossible.\n",
 452                                 data);
 453                 return;
 454         }
 455
 456         tmp = (struct w1_reg_num *) &rn;
 457
 458         slave_count = 0;
 459         list_for_each(ent, &dev->slist) {
 460
 461                 sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 462
 463                 if (sl->reg_num.family == tmp->family &&
 464                     sl->reg_num.id == tmp->id &&
 465                     sl->reg_num.crc == tmp->crc) {
 466                         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 467                         break;
 468                 } else if (sl->reg_num.family == tmp->family) {
 469                         family_found = 1;
 470                         break;
 471                 }
 472
 473                 slave_count++;
 474         }
 475
 476         rn = cpu_to_le64(rn);
 477
 478         if (slave_count == dev->slave_count &&
 479                 rn && ((le64_to_cpu(rn) >> 56) & 0xff) == w1_calc_crc8((u8 *)&rn, 7)) {
 480                 w1_attach_slave_device(dev, tmp);
 481         }
 482
 483         atomic_dec(&dev->refcnt);
 484 }
 485
 486 void w1_search(struct w1_master *dev)
 487 {
 488         u64 last, rn, tmp;
 489         int i, count = 0;
 490         int last_family_desc, last_zero, last_device;
 491         int search_bit, id_bit, comp_bit, desc_bit;
 492
 493         search_bit = id_bit = comp_bit = 0;
 494         rn = tmp = last = 0;
 495         last_device = last_zero = last_family_desc = 0;
 496
 497         desc_bit = 64;
 498
 499         while (!(id_bit && comp_bit) && !last_device &&
 500                count++ < dev->max_slave_count) {
 501                 last = rn;
 502                 rn = 0;
 503
 504                 last_family_desc = 0;
 505
 506                 /*
 507                  * Reset bus and all 1-wire device state machines
 508                  * so they can respond to our requests.
 509                  *
 510                  * Return 0 - device(s) present, 1 - no devices present.
 511                  */
 512                 if (w1_reset_bus(dev)) {
 513                         dev_info(&dev->dev, "No devices present on the wire.\n");
 514                         break;
 515                 }
 516
 517 #if 1
 518                 w1_write_8(dev, W1_SEARCH);
 519                 for (i = 0; i < 64; ++i) {
 520                         /*
 521                          * Read 2 bits from bus.
 522                          * All who don't sleep must send ID bit and COMPLEMENT ID bit.
 523                          * They actually are ANDed between all senders.
 524                          */
 525                         id_bit = w1_touch_bit(dev, 1);
 526                         comp_bit = w1_touch_bit(dev, 1);
 527
 528                         if (id_bit && comp_bit)
 529                                 break;
 530
 531                         if (id_bit == 0 && comp_bit == 0) {
 532                                 if (i == desc_bit)
 533                                         search_bit = 1;
 534                                 else if (i > desc_bit)
 535                                         search_bit = 0;
 536                                 else
 537                                         search_bit = ((last >> i) & 0x1);
 538
 539                                 if (search_bit == 0) {
 540                                         last_zero = i;
 541                                         if (last_zero < 9)
 542                                                 last_family_desc = last_zero;
 543                                 }
 544
 545                         } else
 546                                 search_bit = id_bit;
 547
 548                         tmp = search_bit;
 549                         rn |= (tmp << i);
 550
 551                         /*
 552                          * Write 1 bit to bus
 553                          * and make all who don't have "search_bit" in "i"'th position
 554                          * in it's registration number sleep.
 555                          */
 556                         if (dev->bus_master->touch_bit)
 557                                 w1_touch_bit(dev, search_bit);
 558                         else
 559                                 w1_write_bit(dev, search_bit);
 560
 561                 }
 562 #endif
 563
 564                 if (desc_bit == last_zero)
 565                         last_device = 1;
 566
 567                 desc_bit = last_zero;
 568
 569                 w1_slave_found(dev->bus_master->data, rn);
 570         }
 571 }
 572
 573 static int w1_control(void *data)
 574 {
 575         struct w1_slave *sl, *sln;
 576         struct w1_master *dev, *n;
 577         int err, have_to_wait = 0;
 578
 579         daemonize("w1_control");
 580         allow_signal(SIGTERM);
 581
 582         while (!control_needs_exit || have_to_wait) {
 583                 have_to_wait = 0;
 584
 585                 try_to_freeze(PF_FREEZE);
 586                 msleep_interruptible(w1_timeout * 1000);
 587
 588                 if (signal_pending(current))
 589                         flush_signals(current);
 590
 591                 list_for_each_entry_safe(dev, n, &w1_masters, w1_master_entry) {
 592                         if (!control_needs_exit && !dev->need_exit)
 593                                 continue;
 594                         /*
 595                          * Little race: we can create thread but not set the flag.
 596                          * Get a chance for external process to set flag up.
 597                          */
 598                         if (!dev->initialized) {
 599                                 have_to_wait = 1;
 600                                 continue;
 601                         }
 602
 603                         spin_lock_bh(&w1_mlock);
 604                         list_del(&dev->w1_master_entry);
 605                         spin_unlock_bh(&w1_mlock);
 606
 607                         if (control_needs_exit) {
 608                                 dev->need_exit = 1;
 609
 610                                 err = kill_proc(dev->kpid, SIGTERM, 1);
 611                                 if (err)
 612                                         dev_err(&dev->dev,
 613                                                  "Failed to send signal to w1 kernel thread %d.\n",
 614                                                  dev->kpid);
 615                         }
 616
 617                         wait_for_completion(&dev->dev_exited);
 618
 619                         list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 620                                 list_del(&sl->w1_slave_entry);
 621
 622                                 w1_slave_detach(sl);
 623                                 kfree(sl);
 624                         }
 625                         w1_destroy_master_attributes(dev);
 626                         atomic_dec(&dev->refcnt);
 627                 }
 628         }
 629
 630         complete_and_exit(&w1_control_complete, 0);
 631 }
 632
 633 int w1_process(void *data)
 634 {
 635         struct w1_master *dev = (struct w1_master *) data;
 636         struct w1_slave *sl, *sln;
 637
 638         daemonize("%s", dev->name);
 639         allow_signal(SIGTERM);
 640
 641         while (!dev->need_exit) {
 642                 try_to_freeze(PF_FREEZE);
 643                 msleep_interruptible(w1_timeout * 1000);
 644
 645                 if (signal_pending(current))
 646                         flush_signals(current);
 647
 648                 if (dev->need_exit)
 649                         break;
 650
 651                 if (!dev->initialized)
 652                         continue;
 653
 654                 if (down_interruptible(&dev->mutex))
 655                         continue;
 656
 657                 list_for_each_entry(sl, &dev->slist, w1_slave_entry)
 658                                 clear_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 659
 660                 w1_search_devices(dev, w1_slave_found);
 661
 662                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 663                         if (!test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags) && !--sl->ttl) {
 664                                 list_del (&sl->w1_slave_entry);
 665
 666                                 w1_slave_detach (sl);
 667                                 kfree (sl);
 668
 669                                 dev->slave_count--;
 670                         } else if (test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags))
 671                                 sl->ttl = dev->slave_ttl;
 672                 }
 673                 up(&dev->mutex);
 674         }
 675
 676         atomic_dec(&dev->refcnt);
 677         complete_and_exit(&dev->dev_exited, 0);
 678
 679         return 0;
 680 }
 681
 682 static int w1_init(void)
 683 {
 684         int retval;
 685
 686         printk(KERN_INFO "Driver for 1-wire Dallas network protocol.\n");
 687
 688         retval = bus_register(&w1_bus_type);
 689         if (retval) {
 690                 printk(KERN_ERR "Failed to register bus. err=%d.\n", retval);
 691                 goto err_out_exit_init;
 692         }
 693
 694         retval = driver_register(&w1_driver);
 695         if (retval) {
 696                 printk(KERN_ERR
 697                         "Failed to register master driver. err=%d.\n",
 698                         retval);
 699                 goto err_out_bus_unregister;
 700         }
 701
 702         control_thread = kernel_thread(&w1_control, NULL, 0);
 703         if (control_thread < 0) {
 704                 printk(KERN_ERR "Failed to create control thread. err=%d\n",
 705                         control_thread);
 706                 retval = control_thread;
 707                 goto err_out_driver_unregister;
 708         }
 709
 710         return 0;
 711
 712 err_out_driver_unregister:
 713         driver_unregister(&w1_driver);
 714
 715 err_out_bus_unregister:
 716         bus_unregister(&w1_bus_type);
 717
 718 err_out_exit_init:
 719         return retval;
 720 }
 721
 722 static void w1_fini(void)
 723 {
 724         struct w1_master *dev;
 725
 726         list_for_each_entry(dev, &w1_masters, w1_master_entry)
 727                 __w1_remove_master_device(dev);
 728
 729         control_needs_exit = 1;
 730         wait_for_completion(&w1_control_complete);
 731
 732         driver_unregister(&w1_driver);
 733         bus_unregister(&w1_bus_type);
 734 }
 735
 736 module_init(w1_init);
 737 module_exit(w1_fini);