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);