drivers/w1/w1.c

   1 /*
   2  *      w1.c
   3  *
   4  * Copyright (c) 2004 Evgeniy Polyakov <johnpol@2ka.mipt.ru>
   5  *
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  20  */
  21
  22 #include <linux/delay.h>
  23 #include <linux/kernel.h>
  24 #include <linux/module.h>
  25 #include <linux/moduleparam.h>
  26 #include <linux/list.h>
  27 #include <linux/interrupt.h>
  28 #include <linux/spinlock.h>
  29 #include <linux/timer.h>
  30 #include <linux/device.h>
  31 #include <linux/slab.h>
  32 #include <linux/sched.h>
  33
  34 #include <asm/atomic.h>
  35
  36 #include "w1.h"
  37 #include "w1_io.h"
  38 #include "w1_log.h"
  39 #include "w1_int.h"
  40 #include "w1_family.h"
  41 #include "w1_netlink.h"
  42
  43 MODULE_LICENSE("GPL");
  44 MODULE_AUTHOR("Evgeniy Polyakov <johnpol@2ka.mipt.ru>");
  45 MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol.");
  46
  47 static int w1_timeout = 10;
  48 int w1_max_slave_count = 10;
  49 int w1_max_slave_ttl = 10;
  50
  51 module_param_named(timeout, w1_timeout, int, 0);
  52 module_param_named(max_slave_count, w1_max_slave_count, int, 0);
  53 module_param_named(slave_ttl, w1_max_slave_ttl, int, 0);
  54
  55 DEFINE_SPINLOCK(w1_mlock);
  56 LIST_HEAD(w1_masters);
  57
  58 static pid_t control_thread;
  59 static int control_needs_exit;
  60 static DECLARE_COMPLETION(w1_control_complete);
  61
  62 static int w1_master_match(struct device *dev, struct device_driver *drv)
  63 {
  64         return 1;
  65 }
  66
  67 static int w1_master_probe(struct device *dev)
  68 {
  69         return -ENODEV;
  70 }
  71
  72 static int w1_master_remove(struct device *dev)
  73 {
  74         return 0;
  75 }
  76
  77 static void w1_master_release(struct device *dev)
  78 {
  79         struct w1_master *md = dev_to_w1_master(dev);
  80         complete(&md->dev_released);
  81 }
  82
  83 static void w1_slave_release(struct device *dev)
  84 {
  85         struct w1_slave *sl = dev_to_w1_slave(dev);
  86         complete(&sl->dev_released);
  87 }
  88
  89 static ssize_t w1_slave_read_name(struct device *dev, struct device_attribute *attr, char *buf)
  90 {
  91       struct w1_slave *sl = dev_to_w1_slave(dev);
  92
  93       return sprintf(buf, "%s\n", sl->name);
  94 }
  95
  96 static ssize_t w1_slave_read_id(struct kobject *kobj, char *buf, loff_t off, size_t count)
  97 {
  98       struct w1_slave *sl = kobj_to_w1_slave(kobj);
  99
 100       atomic_inc(&sl->refcnt);
 101       if (off > 8) {
 102               count = 0;
 103         } else {
 104                 if (off + count > 8)
 105                         count = 8 - off;
 106
 107                 memcpy(buf, (u8 *)&sl->reg_num, count);
 108         }
 109         atomic_dec(&sl->refcnt);
 110
 111         return count;
 112   }
 113
 114 static struct device_attribute w1_slave_attr_name =
 115         __ATTR(name, S_IRUGO, w1_slave_read_name, NULL);
 116
 117 static struct bin_attribute w1_slave_attr_bin_id = {
 118       .attr = {
 119               .name = "id",
 120               .mode = S_IRUGO,
 121               .owner = THIS_MODULE,
 122       },
 123       .size = 8,
 124       .read = w1_slave_read_id,
 125 };
 126
 127 /* Default family */
 128 static struct w1_family w1_default_family;
 129
 130 static int w1_hotplug(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size);
 131
 132 static struct bus_type w1_bus_type = {
 133         .name = "w1",
 134         .match = w1_master_match,
 135         .hotplug = w1_hotplug,
 136 };
 137
 138 struct device_driver w1_master_driver = {
 139         .name = "w1_master_driver",
 140         .bus = &w1_bus_type,
 141         .probe = w1_master_probe,
 142         .remove = w1_master_remove,
 143 };
 144
 145 struct device w1_master_device = {
 146         .parent = NULL,
 147         .bus = &w1_bus_type,
 148         .bus_id = "w1 bus master",
 149         .driver = &w1_master_driver,
 150         .release = &w1_master_release
 151 };
 152
 153 struct device_driver w1_slave_driver = {
 154         .name = "w1_slave_driver",
 155         .bus = &w1_bus_type,
 156 };
 157
 158 struct device w1_slave_device = {
 159         .parent = NULL,
 160         .bus = &w1_bus_type,
 161         .bus_id = "w1 bus slave",
 162         .driver = &w1_slave_driver,
 163 };
 164
 165 static ssize_t w1_master_attribute_show_name(struct device *dev, struct device_attribute *attr, char *buf)
 166 {
 167         struct w1_master *md = dev_to_w1_master(dev);
 168         ssize_t count;
 169
 170         if (down_interruptible (&md->mutex))
 171                 return -EBUSY;
 172
 173         count = sprintf(buf, "%s\n", md->name);
 174
 175         up(&md->mutex);
 176
 177         return count;
 178 }
 179
 180 static ssize_t w1_master_attribute_store_search(struct device * dev,
 181                                                 struct device_attribute *attr,
 182                                                 const char * buf, size_t count)
 183 {
 184         struct w1_master *md = dev_to_w1_master(dev);
 185
 186         if (down_interruptible (&md->mutex))
 187                 return -EBUSY;
 188
 189         md->search_count = simple_strtol(buf, NULL, 0);
 190
 191         up(&md->mutex);
 192
 193         return count;
 194 }
 195
 196 static ssize_t w1_master_attribute_show_search(struct device *dev,
 197                                                struct device_attribute *attr,
 198                                                char *buf)
 199 {
 200         struct w1_master *md = dev_to_w1_master(dev);
 201         ssize_t count;
 202
 203         if (down_interruptible (&md->mutex))
 204                 return -EBUSY;
 205
 206         count = sprintf(buf, "%d\n", md->search_count);
 207
 208         up(&md->mutex);
 209
 210         return count;
 211 }
 212
 213 static ssize_t w1_master_attribute_show_pointer(struct device *dev, struct device_attribute *attr, char *buf)
 214 {
 215         struct w1_master *md = dev_to_w1_master(dev);
 216         ssize_t count;
 217
 218         if (down_interruptible(&md->mutex))
 219                 return -EBUSY;
 220
 221         count = sprintf(buf, "0x%p\n", md->bus_master);
 222
 223         up(&md->mutex);
 224         return count;
 225 }
 226
 227 static ssize_t w1_master_attribute_show_timeout(struct device *dev, struct device_attribute *attr, char *buf)
 228 {
 229         ssize_t count;
 230         count = sprintf(buf, "%d\n", w1_timeout);
 231         return count;
 232 }
 233
 234 static ssize_t w1_master_attribute_show_max_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
 235 {
 236         struct w1_master *md = dev_to_w1_master(dev);
 237         ssize_t count;
 238
 239         if (down_interruptible(&md->mutex))
 240                 return -EBUSY;
 241
 242         count = sprintf(buf, "%d\n", md->max_slave_count);
 243
 244         up(&md->mutex);
 245         return count;
 246 }
 247
 248 static ssize_t w1_master_attribute_show_attempts(struct device *dev, struct device_attribute *attr, char *buf)
 249 {
 250         struct w1_master *md = dev_to_w1_master(dev);
 251         ssize_t count;
 252
 253         if (down_interruptible(&md->mutex))
 254                 return -EBUSY;
 255
 256         count = sprintf(buf, "%lu\n", md->attempts);
 257
 258         up(&md->mutex);
 259         return count;
 260 }
 261
 262 static ssize_t w1_master_attribute_show_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
 263 {
 264         struct w1_master *md = dev_to_w1_master(dev);
 265         ssize_t count;
 266
 267         if (down_interruptible(&md->mutex))
 268                 return -EBUSY;
 269
 270         count = sprintf(buf, "%d\n", md->slave_count);
 271
 272         up(&md->mutex);
 273         return count;
 274 }
 275
 276 static ssize_t w1_master_attribute_show_slaves(struct device *dev, struct device_attribute *attr, char *buf)
 277 {
 278         struct w1_master *md = dev_to_w1_master(dev);
 279         int c = PAGE_SIZE;
 280
 281         if (down_interruptible(&md->mutex))
 282                 return -EBUSY;
 283
 284         if (md->slave_count == 0)
 285                 c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n");
 286         else {
 287                 struct list_head *ent, *n;
 288                 struct w1_slave *sl;
 289
 290                 list_for_each_safe(ent, n, &md->slist) {
 291                         sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 292
 293                         c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", sl->name);
 294                 }
 295         }
 296
 297         up(&md->mutex);
 298
 299         return PAGE_SIZE - c;
 300 }
 301
 302 #define W1_MASTER_ATTR_RO(_name, _mode)                         \
 303         struct device_attribute w1_master_attribute_##_name =   \
 304                 __ATTR(w1_master_##_name, _mode,                \
 305                        w1_master_attribute_show_##_name, NULL)
 306
 307 #define W1_MASTER_ATTR_RW(_name, _mode)                         \
 308         struct device_attribute w1_master_attribute_##_name =   \
 309                 __ATTR(w1_master_##_name, _mode,                \
 310                        w1_master_attribute_show_##_name,        \
 311                        w1_master_attribute_store_##_name)
 312
 313 static W1_MASTER_ATTR_RO(name, S_IRUGO);
 314 static W1_MASTER_ATTR_RO(slaves, S_IRUGO);
 315 static W1_MASTER_ATTR_RO(slave_count, S_IRUGO);
 316 static W1_MASTER_ATTR_RO(max_slave_count, S_IRUGO);
 317 static W1_MASTER_ATTR_RO(attempts, S_IRUGO);
 318 static W1_MASTER_ATTR_RO(timeout, S_IRUGO);
 319 static W1_MASTER_ATTR_RO(pointer, S_IRUGO);
 320 static W1_MASTER_ATTR_RW(search, S_IRUGO | S_IWUGO);
 321
 322 static struct attribute *w1_master_default_attrs[] = {
 323         &w1_master_attribute_name.attr,
 324         &w1_master_attribute_slaves.attr,
 325         &w1_master_attribute_slave_count.attr,
 326         &w1_master_attribute_max_slave_count.attr,
 327         &w1_master_attribute_attempts.attr,
 328         &w1_master_attribute_timeout.attr,
 329         &w1_master_attribute_pointer.attr,
 330         &w1_master_attribute_search.attr,
 331         NULL
 332 };
 333
 334 static struct attribute_group w1_master_defattr_group = {
 335         .attrs = w1_master_default_attrs,
 336 };
 337
 338 int w1_create_master_attributes(struct w1_master *master)
 339 {
 340         return sysfs_create_group(&master->dev.kobj, &w1_master_defattr_group);
 341 }
 342
 343 void w1_destroy_master_attributes(struct w1_master *master)
 344 {
 345         sysfs_remove_group(&master->dev.kobj, &w1_master_defattr_group);
 346 }
 347
 348 #ifdef CONFIG_HOTPLUG
 349 static int w1_hotplug(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size)
 350 {
 351         struct w1_master *md = NULL;
 352         struct w1_slave *sl = NULL;
 353         char *event_owner, *name;
 354         int err, cur_index=0, cur_len=0;
 355
 356         if (dev->driver == &w1_master_driver) {
 357                 md = container_of(dev, struct w1_master, dev);
 358                 event_owner = "master";
 359                 name = md->name;
 360         } else if (dev->driver == &w1_slave_driver) {
 361                 sl = container_of(dev, struct w1_slave, dev);
 362                 event_owner = "slave";
 363                 name = sl->name;
 364         } else {
 365                 dev_dbg(dev, "Unknown hotplug event.\n");
 366                 return -EINVAL;
 367         }
 368
 369         dev_dbg(dev, "Hotplug event for %s %s, bus_id=%s.\n", event_owner, name, dev->bus_id);
 370
 371         if (dev->driver != &w1_slave_driver || !sl)
 372                 return 0;
 373
 374         err = add_hotplug_env_var(envp, num_envp, &cur_index, buffer, buffer_size, &cur_len, "W1_FID=%02X", sl->reg_num.family);
 375         if (err)
 376                 return err;
 377
 378         err = add_hotplug_env_var(envp, num_envp, &cur_index, buffer, buffer_size, &cur_len, "W1_SLAVE_ID=%024LX", (u64)sl->reg_num.id);
 379         if (err)
 380                 return err;
 381
 382         return 0;
 383 };
 384 #else
 385 static int w1_hotplug(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size)
 386 {
 387         return 0;
 388 }
 389 #endif
 390
 391 static int __w1_attach_slave_device(struct w1_slave *sl)
 392 {
 393         int err;
 394
 395         sl->dev.parent = &sl->master->dev;
 396         sl->dev.driver = &w1_slave_driver;
 397         sl->dev.bus = &w1_bus_type;
 398         sl->dev.release = &w1_slave_release;
 399
 400         snprintf(&sl->dev.bus_id[0], sizeof(sl->dev.bus_id),
 401                  "%02x-%012llx",
 402                  (unsigned int) sl->reg_num.family,
 403                  (unsigned long long) sl->reg_num.id);
 404         snprintf(&sl->name[0], sizeof(sl->name),
 405                  "%02x-%012llx",
 406                  (unsigned int) sl->reg_num.family,
 407                  (unsigned long long) sl->reg_num.id);
 408
 409         dev_dbg(&sl->dev, "%s: registering %s.\n", __func__,
 410                 &sl->dev.bus_id[0]);
 411
 412         err = device_register(&sl->dev);
 413         if (err < 0) {
 414                 dev_err(&sl->dev,
 415                         "Device registration [%s] failed. err=%d\n",
 416                         sl->dev.bus_id, err);
 417                 return err;
 418         }
 419
 420         /* Create "name" entry */
 421         err = device_create_file(&sl->dev, &w1_slave_attr_name);
 422         if (err < 0) {
 423                 dev_err(&sl->dev,
 424                         "sysfs file creation for [%s] failed. err=%d\n",
 425                         sl->dev.bus_id, err);
 426                 goto out_unreg;
 427         }
 428
 429         /* Create "id" entry */
 430         err = sysfs_create_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
 431         if (err < 0) {
 432                 dev_err(&sl->dev,
 433                         "sysfs file creation for [%s] failed. err=%d\n",
 434                         sl->dev.bus_id, err);
 435                 goto out_rem1;
 436         }
 437
 438         /* if the family driver needs to initialize something... */
 439         if (sl->family->fops && sl->family->fops->add_slave &&
 440             ((err = sl->family->fops->add_slave(sl)) < 0)) {
 441                 dev_err(&sl->dev,
 442                         "sysfs file creation for [%s] failed. err=%d\n",
 443                         sl->dev.bus_id, err);
 444                 goto out_rem2;
 445         }
 446
 447         list_add_tail(&sl->w1_slave_entry, &sl->master->slist);
 448
 449         return 0;
 450
 451 out_rem2:
 452         sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
 453 out_rem1:
 454         device_remove_file(&sl->dev, &w1_slave_attr_name);
 455 out_unreg:
 456         device_unregister(&sl->dev);
 457         return err;
 458 }
 459
 460 static int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
 461 {
 462         struct w1_slave *sl;
 463         struct w1_family *f;
 464         int err;
 465         struct w1_netlink_msg msg;
 466
 467         sl = kmalloc(sizeof(struct w1_slave), GFP_KERNEL);
 468         if (!sl) {
 469                 dev_err(&dev->dev,
 470                          "%s: failed to allocate new slave device.\n",
 471                          __func__);
 472                 return -ENOMEM;
 473         }
 474
 475         memset(sl, 0, sizeof(*sl));
 476
 477         sl->owner = THIS_MODULE;
 478         sl->master = dev;
 479         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 480
 481         memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));
 482         atomic_set(&sl->refcnt, 0);
 483         init_completion(&sl->dev_released);
 484
 485         spin_lock(&w1_flock);
 486         f = w1_family_registered(rn->family);
 487         if (!f) {
 488                 f= &w1_default_family;
 489                 dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n",
 490                           rn->family, rn->family,
 491                           (unsigned long long)rn->id, rn->crc);
 492         }
 493         __w1_family_get(f);
 494         spin_unlock(&w1_flock);
 495
 496         sl->family = f;
 497
 498
 499         err = __w1_attach_slave_device(sl);
 500         if (err < 0) {
 501                 dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__,
 502                          sl->name);
 503                 w1_family_put(sl->family);
 504                 kfree(sl);
 505                 return err;
 506         }
 507
 508         sl->ttl = dev->slave_ttl;
 509         dev->slave_count++;
 510
 511         memcpy(&msg.id.id, rn, sizeof(msg.id.id));
 512         msg.type = W1_SLAVE_ADD;
 513         w1_netlink_send(dev, &msg);
 514
 515         return 0;
 516 }
 517
 518 static void w1_slave_detach(struct w1_slave *sl)
 519 {
 520         struct w1_netlink_msg msg;
 521
 522         dev_info(&sl->dev, "%s: detaching %s.\n", __func__, sl->name);
 523
 524         while (atomic_read(&sl->refcnt)) {
 525                 printk(KERN_INFO "Waiting for %s to become free: refcnt=%d.\n",
 526                                 sl->name, atomic_read(&sl->refcnt));
 527
 528                 if (msleep_interruptible(1000))
 529                         flush_signals(current);
 530         }
 531
 532         if (sl->family->fops && sl->family->fops->remove_slave)
 533                 sl->family->fops->remove_slave(sl);
 534
 535         sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_attr_bin_id);
 536         device_remove_file(&sl->dev, &w1_slave_attr_name);
 537         device_unregister(&sl->dev);
 538         w1_family_put(sl->family);
 539
 540         sl->master->slave_count--;
 541
 542         memcpy(&msg.id.id, &sl->reg_num, sizeof(msg.id.id));
 543         msg.type = W1_SLAVE_REMOVE;
 544         w1_netlink_send(sl->master, &msg);
 545 }
 546
 547 static struct w1_master *w1_search_master(unsigned long data)
 548 {
 549         struct w1_master *dev;
 550         int found = 0;
 551
 552         spin_lock_bh(&w1_mlock);
 553         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 554                 if (dev->bus_master->data == data) {
 555                         found = 1;
 556                         atomic_inc(&dev->refcnt);
 557                         break;
 558                 }
 559         }
 560         spin_unlock_bh(&w1_mlock);
 561
 562         return (found)?dev:NULL;
 563 }
 564
 565 void w1_reconnect_slaves(struct w1_family *f)
 566 {
 567         struct w1_master *dev;
 568
 569         spin_lock_bh(&w1_mlock);
 570         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 571                 dev_info(&dev->dev, "Reconnecting slaves in %s into new family %02x.\n",
 572                                 dev->name, f->fid);
 573                 set_bit(W1_MASTER_NEED_RECONNECT, &dev->flags);
 574         }
 575         spin_unlock_bh(&w1_mlock);
 576 }
 577
 578 static void w1_slave_found(unsigned long data, u64 rn)
 579 {
 580         int slave_count;
 581         struct w1_slave *sl;
 582         struct list_head *ent;
 583         struct w1_reg_num *tmp;
 584         int family_found = 0;
 585         struct w1_master *dev;
 586         u64 rn_le = cpu_to_le64(rn);
 587
 588         dev = w1_search_master(data);
 589         if (!dev) {
 590                 printk(KERN_ERR "Failed to find w1 master device for data %08lx, it is impossible.\n",
 591                                 data);
 592                 return;
 593         }
 594
 595         tmp = (struct w1_reg_num *) &rn;
 596
 597         slave_count = 0;
 598         list_for_each(ent, &dev->slist) {
 599
 600                 sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 601
 602                 if (sl->reg_num.family == tmp->family &&
 603                     sl->reg_num.id == tmp->id &&
 604                     sl->reg_num.crc == tmp->crc) {
 605                         set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 606                         break;
 607                 } else if (sl->reg_num.family == tmp->family) {
 608                         family_found = 1;
 609                         break;
 610                 }
 611
 612                 slave_count++;
 613         }
 614
 615         if (slave_count == dev->slave_count &&
 616                 rn && ((rn >> 56) & 0xff) == w1_calc_crc8((u8 *)&rn_le, 7)) {
 617                 w1_attach_slave_device(dev, tmp);
 618         }
 619
 620         atomic_dec(&dev->refcnt);
 621 }
 622
 623 /**
 624  * Performs a ROM Search & registers any devices found.
 625  * The 1-wire search is a simple binary tree search.
 626  * For each bit of the address, we read two bits and write one bit.
 627  * The bit written will put to sleep all devies that don't match that bit.
 628  * When the two reads differ, the direction choice is obvious.
 629  * When both bits are 0, we must choose a path to take.
 630  * When we can scan all 64 bits without having to choose a path, we are done.
 631  *
 632  * See "Application note 187 1-wire search algorithm" at www.maxim-ic.com
 633  *
 634  * @dev        The master device to search
 635  * @cb         Function to call when a device is found
 636  */
 637 void w1_search(struct w1_master *dev, w1_slave_found_callback cb)
 638 {
 639         u64 last_rn, rn, tmp64;
 640         int i, slave_count = 0;
 641         int last_zero, last_device;
 642         int search_bit, desc_bit;
 643         u8  triplet_ret = 0;
 644
 645         search_bit = 0;
 646         rn = last_rn = 0;
 647         last_device = 0;
 648         last_zero = -1;
 649
 650         desc_bit = 64;
 651
 652         while ( !last_device && (slave_count++ < dev->max_slave_count) ) {
 653                 last_rn = rn;
 654                 rn = 0;
 655
 656                 /*
 657                  * Reset bus and all 1-wire device state machines
 658                  * so they can respond to our requests.
 659                  *
 660                  * Return 0 - device(s) present, 1 - no devices present.
 661                  */
 662                 if (w1_reset_bus(dev)) {
 663                         dev_dbg(&dev->dev, "No devices present on the wire.\n");
 664                         break;
 665                 }
 666
 667                 /* Start the search */
 668                 w1_write_8(dev, W1_SEARCH);
 669                 for (i = 0; i < 64; ++i) {
 670                         /* Determine the direction/search bit */
 671                         if (i == desc_bit)
 672                                 search_bit = 1;   /* took the 0 path last time, so take the 1 path */
 673                         else if (i > desc_bit)
 674                                 search_bit = 0;   /* take the 0 path on the next branch */
 675                         else
 676                                 search_bit = ((last_rn >> i) & 0x1);
 677
 678                         /** Read two bits and write one bit */
 679                         triplet_ret = w1_triplet(dev, search_bit);
 680
 681                         /* quit if no device responded */
 682                         if ( (triplet_ret & 0x03) == 0x03 )
 683                                 break;
 684
 685                         /* If both directions were valid, and we took the 0 path... */
 686                         if (triplet_ret == 0)
 687                                 last_zero = i;
 688
 689                         /* extract the direction taken & update the device number */
 690                         tmp64 = (triplet_ret >> 2);
 691                         rn |= (tmp64 << i);
 692                 }
 693
 694                 if ( (triplet_ret & 0x03) != 0x03 ) {
 695                         if ( (desc_bit == last_zero) || (last_zero < 0))
 696                                 last_device = 1;
 697                         desc_bit = last_zero;
 698                         cb(dev->bus_master->data, rn);
 699                 }
 700         }
 701 }
 702
 703 static int w1_control(void *data)
 704 {
 705         struct w1_slave *sl, *sln;
 706         struct w1_master *dev, *n;
 707         int err, have_to_wait = 0;
 708
 709         daemonize("w1_control");
 710         allow_signal(SIGTERM);
 711
 712         while (!control_needs_exit || have_to_wait) {
 713                 have_to_wait = 0;
 714
 715                 try_to_freeze();
 716                 msleep_interruptible(w1_timeout * 1000);
 717
 718                 if (signal_pending(current))
 719                         flush_signals(current);
 720
 721                 list_for_each_entry_safe(dev, n, &w1_masters, w1_master_entry) {
 722                         if (!control_needs_exit && !dev->flags)
 723                                 continue;
 724                         /*
 725                          * Little race: we can create thread but not set the flag.
 726                          * Get a chance for external process to set flag up.
 727                          */
 728                         if (!dev->initialized) {
 729                                 have_to_wait = 1;
 730                                 continue;
 731                         }
 732
 733                         if (control_needs_exit) {
 734                                 set_bit(W1_MASTER_NEED_EXIT, &dev->flags);
 735
 736                                 err = kill_proc(dev->kpid, SIGTERM, 1);
 737                                 if (err)
 738                                         dev_err(&dev->dev,
 739                                                  "Failed to send signal to w1 kernel thread %d.\n",
 740                                                  dev->kpid);
 741                         }
 742
 743                         if (test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
 744                                 wait_for_completion(&dev->dev_exited);
 745                                 spin_lock_bh(&w1_mlock);
 746                                 list_del(&dev->w1_master_entry);
 747                                 spin_unlock_bh(&w1_mlock);
 748
 749                                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 750                                         list_del(&sl->w1_slave_entry);
 751
 752                                         w1_slave_detach(sl);
 753                                         kfree(sl);
 754                                 }
 755                                 w1_destroy_master_attributes(dev);
 756                                 atomic_dec(&dev->refcnt);
 757                                 continue;
 758                         }
 759
 760                         if (test_bit(W1_MASTER_NEED_RECONNECT, &dev->flags)) {
 761                                 dev_info(&dev->dev, "Reconnecting slaves in device %s.\n", dev->name);
 762                                 down(&dev->mutex);
 763                                 list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
 764                                         if (sl->family->fid == W1_FAMILY_DEFAULT) {
 765                                                 struct w1_reg_num rn;
 766                                                 list_del(&sl->w1_slave_entry);
 767                                                 w1_slave_detach(sl);
 768
 769                                                 memcpy(&rn, &sl->reg_num, sizeof(rn));
 770
 771                                                 kfree(sl);
 772
 773                                                 w1_attach_slave_device(dev, &rn);
 774                                         }
 775                                 }
 776                                 clear_bit(W1_MASTER_NEED_RECONNECT, &dev->flags);
 777                                 up(&dev->mutex);
 778                         }
 779                 }
 780         }
 781
 782         complete_and_exit(&w1_control_complete, 0);
 783 }
 784
 785 int w1_process(void *data)
 786 {
 787         struct w1_master *dev = (struct w1_master *) data;
 788         struct w1_slave *sl, *sln;
 789
 790         daemonize("%s", dev->name);
 791         allow_signal(SIGTERM);
 792
 793         while (!test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
 794                 try_to_freeze();
 795                 msleep_interruptible(w1_timeout * 1000);
 796
 797                 if (signal_pending(current))
 798                         flush_signals(current);
 799
 800                 if (test_bit(W1_MASTER_NEED_EXIT, &dev->flags))
 801                         break;
 802
 803                 if (!dev->initialized)
 804                         continue;
 805
 806                 if (dev->search_count == 0)
 807                         continue;
 808
 809                 if (down_interruptible(&dev->mutex))
 810                         continue;
 811
 812                 list_for_each_entry(sl, &dev->slist, w1_slave_entry)
 813                         clear_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 814
 815                 w1_search_devices(dev, w1_slave_found);
 816
 817                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 818                         if (!test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags) && !--sl->ttl) {
 819                                 list_del (&sl->w1_slave_entry);
 820
 821                                 w1_slave_detach(sl);
 822                                 kfree(sl);
 823
 824                                 dev->slave_count--;
 825                         } else if (test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags))
 826                                 sl->ttl = dev->slave_ttl;
 827                 }
 828
 829                 if (dev->search_count > 0)
 830                         dev->search_count--;
 831
 832                 up(&dev->mutex);
 833         }
 834
 835         atomic_dec(&dev->refcnt);
 836         complete_and_exit(&dev->dev_exited, 0);
 837
 838         return 0;
 839 }
 840
 841 static int w1_init(void)
 842 {
 843         int retval;
 844
 845         printk(KERN_INFO "Driver for 1-wire Dallas network protocol.\n");
 846
 847         retval = bus_register(&w1_bus_type);
 848         if (retval) {
 849                 printk(KERN_ERR "Failed to register bus. err=%d.\n", retval);
 850                 goto err_out_exit_init;
 851         }
 852
 853         retval = driver_register(&w1_master_driver);
 854         if (retval) {
 855                 printk(KERN_ERR
 856                         "Failed to register master driver. err=%d.\n",
 857                         retval);
 858                 goto err_out_bus_unregister;
 859         }
 860
 861         retval = driver_register(&w1_slave_driver);
 862         if (retval) {
 863                 printk(KERN_ERR
 864                         "Failed to register master driver. err=%d.\n",
 865                         retval);
 866                 goto err_out_master_unregister;
 867         }
 868
 869         control_thread = kernel_thread(&w1_control, NULL, 0);
 870         if (control_thread < 0) {
 871                 printk(KERN_ERR "Failed to create control thread. err=%d\n",
 872                         control_thread);
 873                 retval = control_thread;
 874                 goto err_out_slave_unregister;
 875         }
 876
 877         return 0;
 878
 879 err_out_slave_unregister:
 880         driver_unregister(&w1_slave_driver);
 881
 882 err_out_master_unregister:
 883         driver_unregister(&w1_master_driver);
 884
 885 err_out_bus_unregister:
 886         bus_unregister(&w1_bus_type);
 887
 888 err_out_exit_init:
 889         return retval;
 890 }
 891
 892 static void w1_fini(void)
 893 {
 894         struct w1_master *dev;
 895
 896         list_for_each_entry(dev, &w1_masters, w1_master_entry)
 897                 __w1_remove_master_device(dev);
 898
 899         control_needs_exit = 1;
 900         wait_for_completion(&w1_control_complete);
 901
 902         driver_unregister(&w1_slave_driver);
 903         driver_unregister(&w1_master_driver);
 904         bus_unregister(&w1_bus_type);
 905 }
 906
 907 module_init(w1_init);
 908 module_exit(w1_fini);