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 <asm/atomic.h>
  23
  24 #include <linux/delay.h>
  25 #include <linux/kernel.h>
  26 #include <linux/module.h>
  27 #include <linux/moduleparam.h>
  28 #include <linux/list.h>
  29 #include <linux/interrupt.h>
  30 #include <linux/spinlock.h>
  31 #include <linux/timer.h>
  32 #include <linux/device.h>
  33 #include <linux/slab.h>
  34 #include <linux/sched.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 static DECLARE_WAIT_QUEUE_HEAD(w1_control_wait);
  62
  63 static int w1_master_match(struct device *dev, struct device_driver *drv)
  64 {
  65         return 1;
  66 }
  67
  68 static int w1_master_probe(struct device *dev)
  69 {
  70         return -ENODEV;
  71 }
  72
  73 static int w1_master_remove(struct device *dev)
  74 {
  75         return 0;
  76 }
  77
  78 static void w1_master_release(struct device *dev)
  79 {
  80         struct w1_master *md = container_of(dev, struct w1_master, dev);
  81
  82         complete(&md->dev_released);
  83 }
  84
  85 static void w1_slave_release(struct device *dev)
  86 {
  87         struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
  88
  89         complete(&sl->dev_released);
  90 }
  91
  92 static ssize_t w1_default_read_name(struct device *dev, char *buf)
  93 {
  94         return sprintf(buf, "No family registered.\n");
  95 }
  96
  97 static ssize_t w1_default_read_bin(struct kobject *kobj, char *buf, loff_t off,
  98                      size_t count)
  99 {
 100         return sprintf(buf, "No family registered.\n");
 101 }
 102
 103 struct bus_type w1_bus_type = {
 104         .name = "w1",
 105         .match = w1_master_match,
 106 };
 107
 108 struct device_driver w1_driver = {
 109         .name = "w1_driver",
 110         .bus = &w1_bus_type,
 111         .probe = w1_master_probe,
 112         .remove = w1_master_remove,
 113 };
 114
 115 struct device w1_device = {
 116         .parent = NULL,
 117         .bus = &w1_bus_type,
 118         .bus_id = "w1 bus master",
 119         .driver = &w1_driver,
 120         .release = &w1_master_release
 121 };
 122
 123 static struct device_attribute w1_slave_attribute = {
 124         .attr = {
 125                         .name = "name",
 126                         .mode = S_IRUGO,
 127                         .owner = THIS_MODULE
 128         },
 129         .show = &w1_default_read_name,
 130 };
 131
 132 static struct device_attribute w1_slave_attribute_val = {
 133         .attr = {
 134                         .name = "value",
 135                         .mode = S_IRUGO,
 136                         .owner = THIS_MODULE
 137         },
 138         .show = &w1_default_read_name,
 139 };
 140
 141 ssize_t w1_master_attribute_show_name(struct device *dev, char *buf)
 142 {
 143         struct w1_master *md = container_of (dev, struct w1_master, dev);
 144         ssize_t count;
 145
 146         if (down_interruptible (&md->mutex))
 147                 return -EBUSY;
 148
 149         count = sprintf(buf, "%s\n", md->name);
 150
 151         up(&md->mutex);
 152
 153         return count;
 154 }
 155
 156 ssize_t w1_master_attribute_show_pointer(struct device *dev, char *buf)
 157 {
 158         struct w1_master *md = container_of(dev, struct w1_master, dev);
 159         ssize_t count;
 160
 161         if (down_interruptible(&md->mutex))
 162                 return -EBUSY;
 163
 164         count = sprintf(buf, "0x%p\n", md->bus_master);
 165
 166         up(&md->mutex);
 167         return count;
 168 }
 169
 170 ssize_t w1_master_attribute_show_timeout(struct device *dev, char *buf)
 171 {
 172         ssize_t count;
 173         count = sprintf(buf, "%d\n", w1_timeout);
 174         return count;
 175 }
 176
 177 ssize_t w1_master_attribute_show_max_slave_count(struct device *dev, char *buf)
 178 {
 179         struct w1_master *md = container_of(dev, struct w1_master, dev);
 180         ssize_t count;
 181
 182         if (down_interruptible(&md->mutex))
 183                 return -EBUSY;
 184
 185         count = sprintf(buf, "%d\n", md->max_slave_count);
 186
 187         up(&md->mutex);
 188         return count;
 189 }
 190
 191 ssize_t w1_master_attribute_show_attempts(struct device *dev, char *buf)
 192 {
 193         struct w1_master *md = container_of(dev, struct w1_master, dev);
 194         ssize_t count;
 195
 196         if (down_interruptible(&md->mutex))
 197                 return -EBUSY;
 198
 199         count = sprintf(buf, "%lu\n", md->attempts);
 200
 201         up(&md->mutex);
 202         return count;
 203 }
 204
 205 ssize_t w1_master_attribute_show_slave_count(struct device *dev, 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->slave_count);
 214
 215         up(&md->mutex);
 216         return count;
 217 }
 218
 219 ssize_t w1_master_attribute_show_slaves(struct device *dev, char *buf)
 220
 221 {
 222         struct w1_master *md = container_of(dev, struct w1_master, dev);
 223         int c = PAGE_SIZE;
 224
 225         if (down_interruptible(&md->mutex))
 226                 return -EBUSY;
 227
 228         if (md->slave_count == 0)
 229                 c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n");
 230         else {
 231                 struct list_head *ent, *n;
 232                 struct w1_slave *sl;
 233
 234                 list_for_each_safe(ent, n, &md->slist) {
 235                         sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 236
 237                         c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", sl->name);
 238                 }
 239         }
 240
 241         up(&md->mutex);
 242
 243         return PAGE_SIZE - c;
 244 }
 245
 246 static struct device_attribute w1_master_attribute_slaves = {
 247         .attr = {
 248                         .name = "w1_master_slaves",
 249                         .mode = S_IRUGO,
 250                         .owner = THIS_MODULE,
 251         },
 252         .show = &w1_master_attribute_show_slaves,
 253 };
 254 static struct device_attribute w1_master_attribute_slave_count = {
 255         .attr = {
 256                         .name = "w1_master_slave_count",
 257                         .mode = S_IRUGO,
 258                         .owner = THIS_MODULE
 259         },
 260         .show = &w1_master_attribute_show_slave_count,
 261 };
 262 static struct device_attribute w1_master_attribute_attempts = {
 263         .attr = {
 264                         .name = "w1_master_attempts",
 265                         .mode = S_IRUGO,
 266                         .owner = THIS_MODULE
 267         },
 268         .show = &w1_master_attribute_show_attempts,
 269 };
 270 static struct device_attribute w1_master_attribute_max_slave_count = {
 271         .attr = {
 272                         .name = "w1_master_max_slave_count",
 273                         .mode = S_IRUGO,
 274                         .owner = THIS_MODULE
 275         },
 276         .show = &w1_master_attribute_show_max_slave_count,
 277 };
 278 static struct device_attribute w1_master_attribute_timeout = {
 279         .attr = {
 280                         .name = "w1_master_timeout",
 281                         .mode = S_IRUGO,
 282                         .owner = THIS_MODULE
 283         },
 284         .show = &w1_master_attribute_show_timeout,
 285 };
 286 static struct device_attribute w1_master_attribute_pointer = {
 287         .attr = {
 288                         .name = "w1_master_pointer",
 289                         .mode = S_IRUGO,
 290                         .owner = THIS_MODULE
 291         },
 292         .show = &w1_master_attribute_show_pointer,
 293 };
 294 static struct device_attribute w1_master_attribute_name = {
 295         .attr = {
 296                         .name = "w1_master_name",
 297                         .mode = S_IRUGO,
 298                         .owner = THIS_MODULE
 299         },
 300         .show = &w1_master_attribute_show_name,
 301 };
 302
 303 static struct bin_attribute w1_slave_bin_attribute = {
 304         .attr = {
 305                         .name = "w1_slave",
 306                         .mode = S_IRUGO,
 307                         .owner = THIS_MODULE,
 308         },
 309         .size = W1_SLAVE_DATA_SIZE,
 310         .read = &w1_default_read_bin,
 311 };
 312
 313 static int __w1_attach_slave_device(struct w1_slave *sl)
 314 {
 315         int err;
 316
 317         sl->dev.parent = &sl->master->dev;
 318         sl->dev.driver = sl->master->driver;
 319         sl->dev.bus = &w1_bus_type;
 320         sl->dev.release = &w1_slave_release;
 321
 322         snprintf(&sl->dev.bus_id[0], sizeof(sl->dev.bus_id),
 323                   "%02x-%012llx",
 324                   (unsigned int) sl->reg_num.family,
 325                   (unsigned long long) sl->reg_num.id);
 326         snprintf (&sl->name[0], sizeof(sl->name),
 327                   "%02x-%012llx",
 328                   (unsigned int) sl->reg_num.family,
 329                   (unsigned long long) sl->reg_num.id);
 330
 331         dev_dbg(&sl->dev, "%s: registering %s.\n", __func__,
 332                 &sl->dev.bus_id[0]);
 333
 334         err = device_register(&sl->dev);
 335         if (err < 0) {
 336                 dev_err(&sl->dev,
 337                          "Device registration [%s] failed. err=%d\n",
 338                          sl->dev.bus_id, err);
 339                 return err;
 340         }
 341
 342         memcpy(&sl->attr_bin, &w1_slave_bin_attribute, sizeof(sl->attr_bin));
 343         memcpy(&sl->attr_name, &w1_slave_attribute, sizeof(sl->attr_name));
 344         memcpy(&sl->attr_val, &w1_slave_attribute_val, sizeof(sl->attr_val));
 345
 346         sl->attr_bin.read = sl->family->fops->rbin;
 347         sl->attr_name.show = sl->family->fops->rname;
 348         sl->attr_val.show = sl->family->fops->rval;
 349         sl->attr_val.attr.name = sl->family->fops->rvalname;
 350
 351         err = device_create_file(&sl->dev, &sl->attr_name);
 352         if (err < 0) {
 353                 dev_err(&sl->dev,
 354                          "sysfs file creation for [%s] failed. err=%d\n",
 355                          sl->dev.bus_id, err);
 356                 device_unregister(&sl->dev);
 357                 return err;
 358         }
 359
 360         err = device_create_file(&sl->dev, &sl->attr_val);
 361         if (err < 0) {
 362                 dev_err(&sl->dev,
 363                          "sysfs file creation for [%s] failed. err=%d\n",
 364                          sl->dev.bus_id, err);
 365                 device_remove_file(&sl->dev, &sl->attr_name);
 366                 device_unregister(&sl->dev);
 367                 return err;
 368         }
 369
 370         err = sysfs_create_bin_file(&sl->dev.kobj, &sl->attr_bin);
 371         if (err < 0) {
 372                 dev_err(&sl->dev,
 373                          "sysfs file creation for [%s] failed. err=%d\n",
 374                          sl->dev.bus_id, err);
 375                 device_remove_file(&sl->dev, &sl->attr_name);
 376                 device_remove_file(&sl->dev, &sl->attr_val);
 377                 device_unregister(&sl->dev);
 378                 return err;
 379         }
 380
 381         list_add_tail(&sl->w1_slave_entry, &sl->master->slist);
 382
 383         return 0;
 384 }
 385
 386 static int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
 387 {
 388         struct w1_slave *sl;
 389         struct w1_family *f;
 390         int err;
 391         struct w1_netlink_msg msg;
 392
 393         sl = kmalloc(sizeof(struct w1_slave), GFP_KERNEL);
 394         if (!sl) {
 395                 dev_err(&dev->dev,
 396                          "%s: failed to allocate new slave device.\n",
 397                          __func__);
 398                 return -ENOMEM;
 399         }
 400
 401         memset(sl, 0, sizeof(*sl));
 402
 403         sl->owner = THIS_MODULE;
 404         sl->master = dev;
 405         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 406
 407         memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));
 408         atomic_set(&sl->refcnt, 0);
 409         init_completion(&sl->dev_released);
 410
 411         spin_lock(&w1_flock);
 412         f = w1_family_registered(rn->family);
 413         if (!f) {
 414                 spin_unlock(&w1_flock);
 415                 dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n",
 416                           rn->family, rn->family, rn->id, rn->crc);
 417                 kfree(sl);
 418                 return -ENODEV;
 419         }
 420         __w1_family_get(f);
 421         spin_unlock(&w1_flock);
 422
 423         sl->family = f;
 424
 425
 426         err = __w1_attach_slave_device(sl);
 427         if (err < 0) {
 428                 dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__,
 429                          sl->name);
 430                 w1_family_put(sl->family);
 431                 kfree(sl);
 432                 return err;
 433         }
 434
 435         sl->ttl = dev->slave_ttl;
 436         dev->slave_count++;
 437
 438         memcpy(&msg.id.id, rn, sizeof(msg.id.id));
 439         msg.type = W1_SLAVE_ADD;
 440         w1_netlink_send(dev, &msg);
 441
 442         return 0;
 443 }
 444
 445 static void w1_slave_detach(struct w1_slave *sl)
 446 {
 447         struct w1_netlink_msg msg;
 448
 449         dev_info(&sl->dev, "%s: detaching %s.\n", __func__, sl->name);
 450
 451         while (atomic_read(&sl->refcnt)) {
 452                 printk(KERN_INFO "Waiting for %s to become free: refcnt=%d.\n",
 453                                 sl->name, atomic_read(&sl->refcnt));
 454
 455                 if (msleep_interruptible(1000))
 456                         flush_signals(current);
 457         }
 458
 459         sysfs_remove_bin_file (&sl->dev.kobj, &sl->attr_bin);
 460         device_remove_file(&sl->dev, &sl->attr_name);
 461         device_remove_file(&sl->dev, &sl->attr_val);
 462         device_unregister(&sl->dev);
 463         w1_family_put(sl->family);
 464
 465         memcpy(&msg.id.id, &sl->reg_num, sizeof(msg.id.id));
 466         msg.type = W1_SLAVE_REMOVE;
 467         w1_netlink_send(sl->master, &msg);
 468 }
 469
 470 static struct w1_master *w1_search_master(unsigned long data)
 471 {
 472         struct w1_master *dev;
 473         int found = 0;
 474
 475         spin_lock_irq(&w1_mlock);
 476         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 477                 if (dev->bus_master->data == data) {
 478                         found = 1;
 479                         atomic_inc(&dev->refcnt);
 480                         break;
 481                 }
 482         }
 483         spin_unlock_irq(&w1_mlock);
 484
 485         return (found)?dev:NULL;
 486 }
 487
 488 void w1_slave_found(unsigned long data, u64 rn)
 489 {
 490         int slave_count;
 491         struct w1_slave *sl;
 492         struct list_head *ent;
 493         struct w1_reg_num *tmp;
 494         int family_found = 0;
 495         struct w1_master *dev;
 496
 497         dev = w1_search_master(data);
 498         if (!dev) {
 499                 printk(KERN_ERR "Failed to find w1 master device for data %08lx, it is impossible.\n",
 500                                 data);
 501                 return;
 502         }
 503
 504         tmp = (struct w1_reg_num *) &rn;
 505
 506         slave_count = 0;
 507         list_for_each(ent, &dev->slist) {
 508
 509                 sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 510
 511                 if (sl->reg_num.family == tmp->family &&
 512                     sl->reg_num.id == tmp->id &&
 513                     sl->reg_num.crc == tmp->crc) {
 514                         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 515                         break;
 516                 }
 517                 else if (sl->reg_num.family == tmp->family) {
 518                         family_found = 1;
 519                         break;
 520                 }
 521
 522                 slave_count++;
 523         }
 524
 525         if (slave_count == dev->slave_count &&
 526                 rn && ((rn >> 56) & 0xff) == w1_calc_crc8((u8 *)&rn, 7)) {
 527                 w1_attach_slave_device(dev, (struct w1_reg_num *) &rn);
 528         }
 529
 530         atomic_dec(&dev->refcnt);
 531 }
 532
 533 void w1_search(struct w1_master *dev)
 534 {
 535         u64 last, rn, tmp;
 536         int i, count = 0;
 537         int last_family_desc, last_zero, last_device;
 538         int search_bit, id_bit, comp_bit, desc_bit;
 539
 540         search_bit = id_bit = comp_bit = 0;
 541         rn = tmp = last = 0;
 542         last_device = last_zero = last_family_desc = 0;
 543
 544         desc_bit = 64;
 545
 546         while (!(id_bit && comp_bit) && !last_device
 547                 && count++ < dev->max_slave_count) {
 548                 last = rn;
 549                 rn = 0;
 550
 551                 last_family_desc = 0;
 552
 553                 /*
 554                  * Reset bus and all 1-wire device state machines
 555                  * so they can respond to our requests.
 556                  *
 557                  * Return 0 - device(s) present, 1 - no devices present.
 558                  */
 559                 if (w1_reset_bus(dev)) {
 560                         dev_info(&dev->dev, "No devices present on the wire.\n");
 561                         break;
 562                 }
 563
 564 #if 1
 565                 w1_write_8(dev, W1_SEARCH);
 566                 for (i = 0; i < 64; ++i) {
 567                         /*
 568                          * Read 2 bits from bus.
 569                          * All who don't sleep must send ID bit and COMPLEMENT ID bit.
 570                          * They actually are ANDed between all senders.
 571                          */
 572                         id_bit = w1_touch_bit(dev, 1);
 573                         comp_bit = w1_touch_bit(dev, 1);
 574
 575                         if (id_bit && comp_bit)
 576                                 break;
 577
 578                         if (id_bit == 0 && comp_bit == 0) {
 579                                 if (i == desc_bit)
 580                                         search_bit = 1;
 581                                 else if (i > desc_bit)
 582                                         search_bit = 0;
 583                                 else
 584                                         search_bit = ((last >> i) & 0x1);
 585
 586                                 if (search_bit == 0) {
 587                                         last_zero = i;
 588                                         if (last_zero < 9)
 589                                                 last_family_desc = last_zero;
 590                                 }
 591
 592                         }
 593                         else
 594                                 search_bit = id_bit;
 595
 596                         tmp = search_bit;
 597                         rn |= (tmp << i);
 598
 599                         /*
 600                          * Write 1 bit to bus
 601                          * and make all who don't have "search_bit" in "i"'th position
 602                          * in it's registration number sleep.
 603                          */
 604                         if (dev->bus_master->touch_bit)
 605                                 w1_touch_bit(dev, search_bit);
 606                         else
 607                                 w1_write_bit(dev, search_bit);
 608
 609                 }
 610 #endif
 611
 612                 if (desc_bit == last_zero)
 613                         last_device = 1;
 614
 615                 desc_bit = last_zero;
 616
 617                 w1_slave_found(dev->bus_master->data, rn);
 618         }
 619 }
 620
 621 int w1_create_master_attributes(struct w1_master *dev)
 622 {
 623         if (    device_create_file(&dev->dev, &w1_master_attribute_slaves) < 0 ||
 624                 device_create_file(&dev->dev, &w1_master_attribute_slave_count) < 0 ||
 625                 device_create_file(&dev->dev, &w1_master_attribute_attempts) < 0 ||
 626                 device_create_file(&dev->dev, &w1_master_attribute_max_slave_count) < 0 ||
 627                 device_create_file(&dev->dev, &w1_master_attribute_timeout) < 0||
 628                 device_create_file(&dev->dev, &w1_master_attribute_pointer) < 0||
 629                 device_create_file(&dev->dev, &w1_master_attribute_name) < 0)
 630                 return -EINVAL;
 631
 632         return 0;
 633 }
 634
 635 void w1_destroy_master_attributes(struct w1_master *dev)
 636 {
 637         device_remove_file(&dev->dev, &w1_master_attribute_slaves);
 638         device_remove_file(&dev->dev, &w1_master_attribute_slave_count);
 639         device_remove_file(&dev->dev, &w1_master_attribute_attempts);
 640         device_remove_file(&dev->dev, &w1_master_attribute_max_slave_count);
 641         device_remove_file(&dev->dev, &w1_master_attribute_timeout);
 642         device_remove_file(&dev->dev, &w1_master_attribute_pointer);
 643         device_remove_file(&dev->dev, &w1_master_attribute_name);
 644 }
 645
 646
 647 int w1_control(void *data)
 648 {
 649         struct w1_slave *sl;
 650         struct w1_master *dev;
 651         struct list_head *ent, *ment, *n, *mn;
 652         int err, have_to_wait = 0, timeout;
 653
 654         daemonize("w1_control");
 655         allow_signal(SIGTERM);
 656
 657         while (!control_needs_exit || have_to_wait) {
 658                 have_to_wait = 0;
 659
 660                 timeout = w1_timeout*HZ;
 661                 do {
 662                         timeout = interruptible_sleep_on_timeout(&w1_control_wait, timeout);
 663                         try_to_freeze(PF_FREEZE);
 664                 } while (!signal_pending(current) && (timeout > 0));
 665
 666                 if (signal_pending(current))
 667                         flush_signals(current);
 668
 669                 list_for_each_safe(ment, mn, &w1_masters) {
 670                         dev = list_entry(ment, struct w1_master, w1_master_entry);
 671
 672                         if (!control_needs_exit && !dev->need_exit)
 673                                 continue;
 674                         /*
 675                          * Little race: we can create thread but not set the flag.
 676                          * Get a chance for external process to set flag up.
 677                          */
 678                         if (!dev->initialized) {
 679                                 have_to_wait = 1;
 680                                 continue;
 681                         }
 682
 683                         spin_lock(&w1_mlock);
 684                         list_del(&dev->w1_master_entry);
 685                         spin_unlock(&w1_mlock);
 686
 687                         if (control_needs_exit) {
 688                                 dev->need_exit = 1;
 689
 690                                 err = kill_proc(dev->kpid, SIGTERM, 1);
 691                                 if (err)
 692                                         dev_err(&dev->dev,
 693                                                  "Failed to send signal to w1 kernel thread %d.\n",
 694                                                  dev->kpid);
 695                         }
 696
 697                         wait_for_completion(&dev->dev_exited);
 698
 699                         list_for_each_safe(ent, n, &dev->slist) {
 700                                 sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 701
 702                                 if (!sl)
 703                                         dev_warn(&dev->dev,
 704                                                   "%s: slave entry is NULL.\n",
 705                                                   __func__);
 706                                 else {
 707                                         list_del(&sl->w1_slave_entry);
 708
 709                                         w1_slave_detach(sl);
 710                                         kfree(sl);
 711                                 }
 712                         }
 713                         w1_destroy_master_attributes(dev);
 714                         atomic_dec(&dev->refcnt);
 715                 }
 716         }
 717
 718         complete_and_exit(&w1_control_complete, 0);
 719 }
 720
 721 int w1_process(void *data)
 722 {
 723         struct w1_master *dev = (struct w1_master *) data;
 724         unsigned long timeout;
 725         struct list_head *ent, *n;
 726         struct w1_slave *sl;
 727
 728         daemonize("%s", dev->name);
 729         allow_signal(SIGTERM);
 730
 731         while (!dev->need_exit) {
 732                 timeout = w1_timeout*HZ;
 733                 do {
 734                         timeout = interruptible_sleep_on_timeout(&dev->kwait, timeout);
 735                         try_to_freeze(PF_FREEZE);
 736                 } while (!signal_pending(current) && (timeout > 0));
 737
 738                 if (signal_pending(current))
 739                         flush_signals(current);
 740
 741                 if (dev->need_exit)
 742                         break;
 743
 744                 if (!dev->initialized)
 745                         continue;
 746
 747                 if (down_interruptible(&dev->mutex))
 748                         continue;
 749
 750                 list_for_each_safe(ent, n, &dev->slist) {
 751                         sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 752
 753                         if (sl)
 754                                 clear_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 755                 }
 756
 757                 w1_search_devices(dev, w1_slave_found);
 758
 759                 list_for_each_safe(ent, n, &dev->slist) {
 760                         sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 761
 762                         if (sl && !test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags) && !--sl->ttl) {
 763                                 list_del (&sl->w1_slave_entry);
 764
 765                                 w1_slave_detach (sl);
 766                                 kfree (sl);
 767
 768                                 dev->slave_count--;
 769                         }
 770                         else if (test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags))
 771                                 sl->ttl = dev->slave_ttl;
 772                 }
 773                 up(&dev->mutex);
 774         }
 775
 776         atomic_dec(&dev->refcnt);
 777         complete_and_exit(&dev->dev_exited, 0);
 778
 779         return 0;
 780 }
 781
 782 int w1_init(void)
 783 {
 784         int retval;
 785
 786         printk(KERN_INFO "Driver for 1-wire Dallas network protocol.\n");
 787
 788         retval = bus_register(&w1_bus_type);
 789         if (retval) {
 790                 printk(KERN_ERR "Failed to register bus. err=%d.\n", retval);
 791                 goto err_out_exit_init;
 792         }
 793
 794         retval = driver_register(&w1_driver);
 795         if (retval) {
 796                 printk(KERN_ERR
 797                         "Failed to register master driver. err=%d.\n",
 798                         retval);
 799                 goto err_out_bus_unregister;
 800         }
 801
 802         control_thread = kernel_thread(&w1_control, NULL, 0);
 803         if (control_thread < 0) {
 804                 printk(KERN_ERR "Failed to create control thread. err=%d\n",
 805                         control_thread);
 806                 retval = control_thread;
 807                 goto err_out_driver_unregister;
 808         }
 809
 810         return 0;
 811
 812 err_out_driver_unregister:
 813         driver_unregister(&w1_driver);
 814
 815 err_out_bus_unregister:
 816         bus_unregister(&w1_bus_type);
 817
 818 err_out_exit_init:
 819         return retval;
 820 }
 821
 822 void w1_fini(void)
 823 {
 824         struct w1_master *dev;
 825         struct list_head *ent, *n;
 826
 827         list_for_each_safe(ent, n, &w1_masters) {
 828                 dev = list_entry(ent, struct w1_master, w1_master_entry);
 829                 __w1_remove_master_device(dev);
 830         }
 831
 832         control_needs_exit = 1;
 833
 834         wait_for_completion(&w1_control_complete);
 835
 836         driver_unregister(&w1_driver);
 837         bus_unregister(&w1_bus_type);
 838 }
 839
 840 module_init(w1_init);
 841 module_exit(w1_fini);
 842
 843 EXPORT_SYMBOL(w1_create_master_attributes);
 844 EXPORT_SYMBOL(w1_destroy_master_attributes);