drivers/w1/w1.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
   4  */
   5
   6 #include <linux/delay.h>
   7 #include <linux/kernel.h>
   8 #include <linux/module.h>
   9 #include <linux/moduleparam.h>
  10 #include <linux/list.h>
  11 #include <linux/interrupt.h>
  12 #include <linux/spinlock.h>
  13 #include <linux/timer.h>
  14 #include <linux/device.h>
  15 #include <linux/slab.h>
  16 #include <linux/sched.h>
  17 #include <linux/kthread.h>
  18 #include <linux/freezer.h>
  19 #include <linux/hwmon.h>
  20 #include <linux/of.h>
  21
  22 #include <linux/atomic.h>
  23
  24 #include "w1_internal.h"
  25 #include "w1_netlink.h"
  26
  27 #define W1_FAMILY_DEFAULT       0
  28 #define W1_FAMILY_DS28E04       0x1C /* for crc quirk */
  29
  30
  31 static int w1_timeout = 10;
  32 module_param_named(timeout, w1_timeout, int, 0);
  33 MODULE_PARM_DESC(timeout, "time in seconds between automatic slave searches");
  34
  35 static int w1_timeout_us = 0;
  36 module_param_named(timeout_us, w1_timeout_us, int, 0);
  37 MODULE_PARM_DESC(timeout_us,
  38                  "time in microseconds between automatic slave searches");
  39
  40 /* A search stops when w1_max_slave_count devices have been found in that
  41  * search.  The next search will start over and detect the same set of devices
  42  * on a static 1-wire bus.  Memory is not allocated based on this number, just
  43  * on the number of devices known to the kernel.  Having a high number does not
  44  * consume additional resources.  As a special case, if there is only one
  45  * device on the network and w1_max_slave_count is set to 1, the device id can
  46  * be read directly skipping the normal slower search process.
  47  */
  48 int w1_max_slave_count = 64;
  49 module_param_named(max_slave_count, w1_max_slave_count, int, 0);
  50 MODULE_PARM_DESC(max_slave_count,
  51         "maximum number of slaves detected in a search");
  52
  53 int w1_max_slave_ttl = 10;
  54 module_param_named(slave_ttl, w1_max_slave_ttl, int, 0);
  55 MODULE_PARM_DESC(slave_ttl,
  56         "Number of searches not seeing a slave before it will be removed");
  57
  58 DEFINE_MUTEX(w1_mlock);
  59 LIST_HEAD(w1_masters);
  60
  61 static int w1_master_match(struct device *dev, struct device_driver *drv)
  62 {
  63         return 1;
  64 }
  65
  66 static int w1_master_probe(struct device *dev)
  67 {
  68         return -ENODEV;
  69 }
  70
  71 static void w1_master_release(struct device *dev)
  72 {
  73         struct w1_master *md = dev_to_w1_master(dev);
  74
  75         dev_dbg(dev, "%s: Releasing %s.\n", __func__, md->name);
  76         memset(md, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master));
  77         kfree(md);
  78 }
  79
  80 static void w1_slave_release(struct device *dev)
  81 {
  82         struct w1_slave *sl = dev_to_w1_slave(dev);
  83
  84         dev_dbg(dev, "%s: Releasing %s [%p]\n", __func__, sl->name, sl);
  85
  86         w1_family_put(sl->family);
  87         sl->master->slave_count--;
  88 }
  89
  90 static ssize_t name_show(struct device *dev, struct device_attribute *attr, char *buf)
  91 {
  92         struct w1_slave *sl = dev_to_w1_slave(dev);
  93
  94         return sprintf(buf, "%s\n", sl->name);
  95 }
  96 static DEVICE_ATTR_RO(name);
  97
  98 static ssize_t id_show(struct device *dev,
  99         struct device_attribute *attr, char *buf)
 100 {
 101         struct w1_slave *sl = dev_to_w1_slave(dev);
 102         ssize_t count = sizeof(sl->reg_num);
 103
 104         memcpy(buf, (u8 *)&sl->reg_num, count);
 105         return count;
 106 }
 107 static DEVICE_ATTR_RO(id);
 108
 109 static struct attribute *w1_slave_attrs[] = {
 110         &dev_attr_name.attr,
 111         &dev_attr_id.attr,
 112         NULL,
 113 };
 114 ATTRIBUTE_GROUPS(w1_slave);
 115
 116 /* Default family */
 117
 118 static ssize_t rw_write(struct file *filp, struct kobject *kobj,
 119                         struct bin_attribute *bin_attr, char *buf, loff_t off,
 120                         size_t count)
 121 {
 122         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 123
 124         mutex_lock(&sl->master->mutex);
 125         if (w1_reset_select_slave(sl)) {
 126                 count = 0;
 127                 goto out_up;
 128         }
 129
 130         w1_write_block(sl->master, buf, count);
 131
 132 out_up:
 133         mutex_unlock(&sl->master->mutex);
 134         return count;
 135 }
 136
 137 static ssize_t rw_read(struct file *filp, struct kobject *kobj,
 138                        struct bin_attribute *bin_attr, char *buf, loff_t off,
 139                        size_t count)
 140 {
 141         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 142
 143         mutex_lock(&sl->master->mutex);
 144         w1_read_block(sl->master, buf, count);
 145         mutex_unlock(&sl->master->mutex);
 146         return count;
 147 }
 148
 149 static BIN_ATTR_RW(rw, PAGE_SIZE);
 150
 151 static struct bin_attribute *w1_slave_bin_attrs[] = {
 152         &bin_attr_rw,
 153         NULL,
 154 };
 155
 156 static const struct attribute_group w1_slave_default_group = {
 157         .bin_attrs = w1_slave_bin_attrs,
 158 };
 159
 160 static const struct attribute_group *w1_slave_default_groups[] = {
 161         &w1_slave_default_group,
 162         NULL,
 163 };
 164
 165 static const struct w1_family_ops w1_default_fops = {
 166         .groups         = w1_slave_default_groups,
 167 };
 168
 169 static struct w1_family w1_default_family = {
 170         .fops = &w1_default_fops,
 171 };
 172
 173 static int w1_uevent(struct device *dev, struct kobj_uevent_env *env);
 174
 175 static struct bus_type w1_bus_type = {
 176         .name = "w1",
 177         .match = w1_master_match,
 178         .uevent = w1_uevent,
 179 };
 180
 181 struct device_driver w1_master_driver = {
 182         .name = "w1_master_driver",
 183         .bus = &w1_bus_type,
 184         .probe = w1_master_probe,
 185 };
 186
 187 struct device w1_master_device = {
 188         .parent = NULL,
 189         .bus = &w1_bus_type,
 190         .init_name = "w1 bus master",
 191         .driver = &w1_master_driver,
 192         .release = &w1_master_release
 193 };
 194
 195 static struct device_driver w1_slave_driver = {
 196         .name = "w1_slave_driver",
 197         .bus = &w1_bus_type,
 198 };
 199
 200 #if 0
 201 struct device w1_slave_device = {
 202         .parent = NULL,
 203         .bus = &w1_bus_type,
 204         .init_name = "w1 bus slave",
 205         .driver = &w1_slave_driver,
 206         .release = &w1_slave_release
 207 };
 208 #endif  /*  0  */
 209
 210 static ssize_t w1_master_attribute_show_name(struct device *dev, struct device_attribute *attr, char *buf)
 211 {
 212         struct w1_master *md = dev_to_w1_master(dev);
 213         ssize_t count;
 214
 215         mutex_lock(&md->mutex);
 216         count = sprintf(buf, "%s\n", md->name);
 217         mutex_unlock(&md->mutex);
 218
 219         return count;
 220 }
 221
 222 static ssize_t w1_master_attribute_store_search(struct device * dev,
 223                                                 struct device_attribute *attr,
 224                                                 const char * buf, size_t count)
 225 {
 226         long tmp;
 227         struct w1_master *md = dev_to_w1_master(dev);
 228         int ret;
 229
 230         ret = kstrtol(buf, 0, &tmp);
 231         if (ret)
 232                 return ret;
 233
 234         mutex_lock(&md->mutex);
 235         md->search_count = tmp;
 236         mutex_unlock(&md->mutex);
 237         /* Only wake if it is going to be searching. */
 238         if (tmp)
 239                 wake_up_process(md->thread);
 240
 241         return count;
 242 }
 243
 244 static ssize_t w1_master_attribute_show_search(struct device *dev,
 245                                                struct device_attribute *attr,
 246                                                char *buf)
 247 {
 248         struct w1_master *md = dev_to_w1_master(dev);
 249         ssize_t count;
 250
 251         mutex_lock(&md->mutex);
 252         count = sprintf(buf, "%d\n", md->search_count);
 253         mutex_unlock(&md->mutex);
 254
 255         return count;
 256 }
 257
 258 static ssize_t w1_master_attribute_store_pullup(struct device *dev,
 259                                                 struct device_attribute *attr,
 260                                                 const char *buf, size_t count)
 261 {
 262         long tmp;
 263         struct w1_master *md = dev_to_w1_master(dev);
 264         int ret;
 265
 266         ret = kstrtol(buf, 0, &tmp);
 267         if (ret)
 268                 return ret;
 269
 270         mutex_lock(&md->mutex);
 271         md->enable_pullup = tmp;
 272         mutex_unlock(&md->mutex);
 273
 274         return count;
 275 }
 276
 277 static ssize_t w1_master_attribute_show_pullup(struct device *dev,
 278                                                struct device_attribute *attr,
 279                                                char *buf)
 280 {
 281         struct w1_master *md = dev_to_w1_master(dev);
 282         ssize_t count;
 283
 284         mutex_lock(&md->mutex);
 285         count = sprintf(buf, "%d\n", md->enable_pullup);
 286         mutex_unlock(&md->mutex);
 287
 288         return count;
 289 }
 290
 291 static ssize_t w1_master_attribute_show_pointer(struct device *dev, struct device_attribute *attr, char *buf)
 292 {
 293         struct w1_master *md = dev_to_w1_master(dev);
 294         ssize_t count;
 295
 296         mutex_lock(&md->mutex);
 297         count = sprintf(buf, "0x%p\n", md->bus_master);
 298         mutex_unlock(&md->mutex);
 299         return count;
 300 }
 301
 302 static ssize_t w1_master_attribute_show_timeout(struct device *dev, struct device_attribute *attr, char *buf)
 303 {
 304         ssize_t count;
 305         count = sprintf(buf, "%d\n", w1_timeout);
 306         return count;
 307 }
 308
 309 static ssize_t w1_master_attribute_show_timeout_us(struct device *dev,
 310         struct device_attribute *attr, char *buf)
 311 {
 312         ssize_t count;
 313         count = sprintf(buf, "%d\n", w1_timeout_us);
 314         return count;
 315 }
 316
 317 static ssize_t w1_master_attribute_store_max_slave_count(struct device *dev,
 318         struct device_attribute *attr, const char *buf, size_t count)
 319 {
 320         int tmp;
 321         struct w1_master *md = dev_to_w1_master(dev);
 322
 323         if (kstrtoint(buf, 0, &tmp) || tmp < 1)
 324                 return -EINVAL;
 325
 326         mutex_lock(&md->mutex);
 327         md->max_slave_count = tmp;
 328         /* allow each time the max_slave_count is updated */
 329         clear_bit(W1_WARN_MAX_COUNT, &md->flags);
 330         mutex_unlock(&md->mutex);
 331
 332         return count;
 333 }
 334
 335 static ssize_t w1_master_attribute_show_max_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
 336 {
 337         struct w1_master *md = dev_to_w1_master(dev);
 338         ssize_t count;
 339
 340         mutex_lock(&md->mutex);
 341         count = sprintf(buf, "%d\n", md->max_slave_count);
 342         mutex_unlock(&md->mutex);
 343         return count;
 344 }
 345
 346 static ssize_t w1_master_attribute_show_attempts(struct device *dev, struct device_attribute *attr, char *buf)
 347 {
 348         struct w1_master *md = dev_to_w1_master(dev);
 349         ssize_t count;
 350
 351         mutex_lock(&md->mutex);
 352         count = sprintf(buf, "%lu\n", md->attempts);
 353         mutex_unlock(&md->mutex);
 354         return count;
 355 }
 356
 357 static ssize_t w1_master_attribute_show_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
 358 {
 359         struct w1_master *md = dev_to_w1_master(dev);
 360         ssize_t count;
 361
 362         mutex_lock(&md->mutex);
 363         count = sprintf(buf, "%d\n", md->slave_count);
 364         mutex_unlock(&md->mutex);
 365         return count;
 366 }
 367
 368 static ssize_t w1_master_attribute_show_slaves(struct device *dev,
 369         struct device_attribute *attr, char *buf)
 370 {
 371         struct w1_master *md = dev_to_w1_master(dev);
 372         int c = PAGE_SIZE;
 373         struct list_head *ent, *n;
 374         struct w1_slave *sl = NULL;
 375
 376         mutex_lock(&md->list_mutex);
 377
 378         list_for_each_safe(ent, n, &md->slist) {
 379                 sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 380
 381                 c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", sl->name);
 382         }
 383         if (!sl)
 384                 c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n");
 385
 386         mutex_unlock(&md->list_mutex);
 387
 388         return PAGE_SIZE - c;
 389 }
 390
 391 static ssize_t w1_master_attribute_show_add(struct device *dev,
 392         struct device_attribute *attr, char *buf)
 393 {
 394         int c = PAGE_SIZE;
 395         c -= snprintf(buf+PAGE_SIZE - c, c,
 396                 "write device id xx-xxxxxxxxxxxx to add slave\n");
 397         return PAGE_SIZE - c;
 398 }
 399
 400 static int w1_atoreg_num(struct device *dev, const char *buf, size_t count,
 401         struct w1_reg_num *rn)
 402 {
 403         unsigned int family;
 404         unsigned long long id;
 405         int i;
 406         u64 rn64_le;
 407
 408         /* The CRC value isn't read from the user because the sysfs directory
 409          * doesn't include it and most messages from the bus search don't
 410          * print it either.  It would be unreasonable for the user to then
 411          * provide it.
 412          */
 413         const char *error_msg = "bad slave string format, expecting "
 414                 "ff-dddddddddddd\n";
 415
 416         if (buf[2] != '-') {
 417                 dev_err(dev, "%s", error_msg);
 418                 return -EINVAL;
 419         }
 420         i = sscanf(buf, "%02x-%012llx", &family, &id);
 421         if (i != 2) {
 422                 dev_err(dev, "%s", error_msg);
 423                 return -EINVAL;
 424         }
 425         rn->family = family;
 426         rn->id = id;
 427
 428         rn64_le = cpu_to_le64(*(u64 *)rn);
 429         rn->crc = w1_calc_crc8((u8 *)&rn64_le, 7);
 430
 431 #if 0
 432         dev_info(dev, "With CRC device is %02x.%012llx.%02x.\n",
 433                   rn->family, (unsigned long long)rn->id, rn->crc);
 434 #endif
 435
 436         return 0;
 437 }
 438
 439 /* Searches the slaves in the w1_master and returns a pointer or NULL.
 440  * Note: must not hold list_mutex
 441  */
 442 struct w1_slave *w1_slave_search_device(struct w1_master *dev,
 443         struct w1_reg_num *rn)
 444 {
 445         struct w1_slave *sl;
 446         mutex_lock(&dev->list_mutex);
 447         list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
 448                 if (sl->reg_num.family == rn->family &&
 449                                 sl->reg_num.id == rn->id &&
 450                                 sl->reg_num.crc == rn->crc) {
 451                         mutex_unlock(&dev->list_mutex);
 452                         return sl;
 453                 }
 454         }
 455         mutex_unlock(&dev->list_mutex);
 456         return NULL;
 457 }
 458
 459 static ssize_t w1_master_attribute_store_add(struct device *dev,
 460                                                 struct device_attribute *attr,
 461                                                 const char *buf, size_t count)
 462 {
 463         struct w1_master *md = dev_to_w1_master(dev);
 464         struct w1_reg_num rn;
 465         struct w1_slave *sl;
 466         ssize_t result = count;
 467
 468         if (w1_atoreg_num(dev, buf, count, &rn))
 469                 return -EINVAL;
 470
 471         mutex_lock(&md->mutex);
 472         sl = w1_slave_search_device(md, &rn);
 473         /* It would be nice to do a targeted search one the one-wire bus
 474          * for the new device to see if it is out there or not.  But the
 475          * current search doesn't support that.
 476          */
 477         if (sl) {
 478                 dev_info(dev, "Device %s already exists\n", sl->name);
 479                 result = -EINVAL;
 480         } else {
 481                 w1_attach_slave_device(md, &rn);
 482         }
 483         mutex_unlock(&md->mutex);
 484
 485         return result;
 486 }
 487
 488 static ssize_t w1_master_attribute_show_remove(struct device *dev,
 489         struct device_attribute *attr, char *buf)
 490 {
 491         int c = PAGE_SIZE;
 492         c -= snprintf(buf+PAGE_SIZE - c, c,
 493                 "write device id xx-xxxxxxxxxxxx to remove slave\n");
 494         return PAGE_SIZE - c;
 495 }
 496
 497 static ssize_t w1_master_attribute_store_remove(struct device *dev,
 498                                                 struct device_attribute *attr,
 499                                                 const char *buf, size_t count)
 500 {
 501         struct w1_master *md = dev_to_w1_master(dev);
 502         struct w1_reg_num rn;
 503         struct w1_slave *sl;
 504         ssize_t result = count;
 505
 506         if (w1_atoreg_num(dev, buf, count, &rn))
 507                 return -EINVAL;
 508
 509         mutex_lock(&md->mutex);
 510         sl = w1_slave_search_device(md, &rn);
 511         if (sl) {
 512                 result = w1_slave_detach(sl);
 513                 /* refcnt 0 means it was detached in the call */
 514                 if (result == 0)
 515                         result = count;
 516         } else {
 517                 dev_info(dev, "Device %02x-%012llx doesn't exists\n", rn.family,
 518                         (unsigned long long)rn.id);
 519                 result = -EINVAL;
 520         }
 521         mutex_unlock(&md->mutex);
 522
 523         return result;
 524 }
 525
 526 #define W1_MASTER_ATTR_RO(_name, _mode)                         \
 527         struct device_attribute w1_master_attribute_##_name =   \
 528                 __ATTR(w1_master_##_name, _mode,                \
 529                        w1_master_attribute_show_##_name, NULL)
 530
 531 #define W1_MASTER_ATTR_RW(_name, _mode)                         \
 532         struct device_attribute w1_master_attribute_##_name =   \
 533                 __ATTR(w1_master_##_name, _mode,                \
 534                        w1_master_attribute_show_##_name,        \
 535                        w1_master_attribute_store_##_name)
 536
 537 static W1_MASTER_ATTR_RO(name, S_IRUGO);
 538 static W1_MASTER_ATTR_RO(slaves, S_IRUGO);
 539 static W1_MASTER_ATTR_RO(slave_count, S_IRUGO);
 540 static W1_MASTER_ATTR_RW(max_slave_count, S_IRUGO | S_IWUSR | S_IWGRP);
 541 static W1_MASTER_ATTR_RO(attempts, S_IRUGO);
 542 static W1_MASTER_ATTR_RO(timeout, S_IRUGO);
 543 static W1_MASTER_ATTR_RO(timeout_us, S_IRUGO);
 544 static W1_MASTER_ATTR_RO(pointer, S_IRUGO);
 545 static W1_MASTER_ATTR_RW(search, S_IRUGO | S_IWUSR | S_IWGRP);
 546 static W1_MASTER_ATTR_RW(pullup, S_IRUGO | S_IWUSR | S_IWGRP);
 547 static W1_MASTER_ATTR_RW(add, S_IRUGO | S_IWUSR | S_IWGRP);
 548 static W1_MASTER_ATTR_RW(remove, S_IRUGO | S_IWUSR | S_IWGRP);
 549
 550 static struct attribute *w1_master_default_attrs[] = {
 551         &w1_master_attribute_name.attr,
 552         &w1_master_attribute_slaves.attr,
 553         &w1_master_attribute_slave_count.attr,
 554         &w1_master_attribute_max_slave_count.attr,
 555         &w1_master_attribute_attempts.attr,
 556         &w1_master_attribute_timeout.attr,
 557         &w1_master_attribute_timeout_us.attr,
 558         &w1_master_attribute_pointer.attr,
 559         &w1_master_attribute_search.attr,
 560         &w1_master_attribute_pullup.attr,
 561         &w1_master_attribute_add.attr,
 562         &w1_master_attribute_remove.attr,
 563         NULL
 564 };
 565
 566 static const struct attribute_group w1_master_defattr_group = {
 567         .attrs = w1_master_default_attrs,
 568 };
 569
 570 int w1_create_master_attributes(struct w1_master *master)
 571 {
 572         return sysfs_create_group(&master->dev.kobj, &w1_master_defattr_group);
 573 }
 574
 575 void w1_destroy_master_attributes(struct w1_master *master)
 576 {
 577         sysfs_remove_group(&master->dev.kobj, &w1_master_defattr_group);
 578 }
 579
 580 static int w1_uevent(struct device *dev, struct kobj_uevent_env *env)
 581 {
 582         struct w1_master *md = NULL;
 583         struct w1_slave *sl = NULL;
 584         char *event_owner, *name;
 585         int err = 0;
 586
 587         if (dev->driver == &w1_master_driver) {
 588                 md = container_of(dev, struct w1_master, dev);
 589                 event_owner = "master";
 590                 name = md->name;
 591         } else if (dev->driver == &w1_slave_driver) {
 592                 sl = container_of(dev, struct w1_slave, dev);
 593                 event_owner = "slave";
 594                 name = sl->name;
 595         } else {
 596                 dev_dbg(dev, "Unknown event.\n");
 597                 return -EINVAL;
 598         }
 599
 600         dev_dbg(dev, "Hotplug event for %s %s, bus_id=%s.\n",
 601                         event_owner, name, dev_name(dev));
 602
 603         if (dev->driver != &w1_slave_driver || !sl)
 604                 goto end;
 605
 606         err = add_uevent_var(env, "W1_FID=%02X", sl->reg_num.family);
 607         if (err)
 608                 goto end;
 609
 610         err = add_uevent_var(env, "W1_SLAVE_ID=%024LX",
 611                              (unsigned long long)sl->reg_num.id);
 612 end:
 613         return err;
 614 }
 615
 616 static int w1_family_notify(unsigned long action, struct w1_slave *sl)
 617 {
 618         const struct w1_family_ops *fops;
 619         int err;
 620
 621         fops = sl->family->fops;
 622
 623         if (!fops)
 624                 return 0;
 625
 626         switch (action) {
 627         case BUS_NOTIFY_ADD_DEVICE:
 628                 /* if the family driver needs to initialize something... */
 629                 if (fops->add_slave) {
 630                         err = fops->add_slave(sl);
 631                         if (err < 0) {
 632                                 dev_err(&sl->dev,
 633                                         "add_slave() call failed. err=%d\n",
 634                                         err);
 635                                 return err;
 636                         }
 637                 }
 638                 if (fops->groups) {
 639                         err = sysfs_create_groups(&sl->dev.kobj, fops->groups);
 640                         if (err) {
 641                                 dev_err(&sl->dev,
 642                                         "sysfs group creation failed. err=%d\n",
 643                                         err);
 644                                 return err;
 645                         }
 646                 }
 647                 if (IS_REACHABLE(CONFIG_HWMON) && fops->chip_info) {
 648                         struct device *hwmon
 649                                 = hwmon_device_register_with_info(&sl->dev,
 650                                                 "w1_slave_temp", sl,
 651                                                 fops->chip_info,
 652                                                 NULL);
 653                         if (IS_ERR(hwmon)) {
 654                                 dev_warn(&sl->dev,
 655                                          "could not create hwmon device\n");
 656                         } else {
 657                                 sl->hwmon = hwmon;
 658                         }
 659                 }
 660                 break;
 661         case BUS_NOTIFY_DEL_DEVICE:
 662                 if (IS_REACHABLE(CONFIG_HWMON) && fops->chip_info &&
 663                             sl->hwmon)
 664                         hwmon_device_unregister(sl->hwmon);
 665                 if (fops->remove_slave)
 666                         sl->family->fops->remove_slave(sl);
 667                 if (fops->groups)
 668                         sysfs_remove_groups(&sl->dev.kobj, fops->groups);
 669                 break;
 670         }
 671         return 0;
 672 }
 673
 674 static int __w1_attach_slave_device(struct w1_slave *sl)
 675 {
 676         int err;
 677
 678         sl->dev.parent = &sl->master->dev;
 679         sl->dev.driver = &w1_slave_driver;
 680         sl->dev.bus = &w1_bus_type;
 681         sl->dev.release = &w1_slave_release;
 682         sl->dev.groups = w1_slave_groups;
 683         sl->dev.of_node = of_find_matching_node(sl->master->dev.of_node,
 684                                                 sl->family->of_match_table);
 685
 686         dev_set_name(&sl->dev, "%02x-%012llx",
 687                  (unsigned int) sl->reg_num.family,
 688                  (unsigned long long) sl->reg_num.id);
 689         snprintf(&sl->name[0], sizeof(sl->name),
 690                  "%02x-%012llx",
 691                  (unsigned int) sl->reg_num.family,
 692                  (unsigned long long) sl->reg_num.id);
 693
 694         dev_dbg(&sl->dev, "%s: registering %s as %p.\n", __func__,
 695                 dev_name(&sl->dev), sl);
 696
 697         /* suppress for w1_family_notify before sending KOBJ_ADD */
 698         dev_set_uevent_suppress(&sl->dev, true);
 699
 700         err = device_register(&sl->dev);
 701         if (err < 0) {
 702                 dev_err(&sl->dev,
 703                         "Device registration [%s] failed. err=%d\n",
 704                         dev_name(&sl->dev), err);
 705                 put_device(&sl->dev);
 706                 return err;
 707         }
 708         w1_family_notify(BUS_NOTIFY_ADD_DEVICE, sl);
 709
 710         dev_set_uevent_suppress(&sl->dev, false);
 711         kobject_uevent(&sl->dev.kobj, KOBJ_ADD);
 712
 713         mutex_lock(&sl->master->list_mutex);
 714         list_add_tail(&sl->w1_slave_entry, &sl->master->slist);
 715         mutex_unlock(&sl->master->list_mutex);
 716
 717         return 0;
 718 }
 719
 720 int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
 721 {
 722         struct w1_slave *sl;
 723         struct w1_family *f;
 724         int err;
 725         struct w1_netlink_msg msg;
 726
 727         sl = kzalloc(sizeof(struct w1_slave), GFP_KERNEL);
 728         if (!sl) {
 729                 dev_err(&dev->dev,
 730                          "%s: failed to allocate new slave device.\n",
 731                          __func__);
 732                 return -ENOMEM;
 733         }
 734
 735
 736         sl->owner = THIS_MODULE;
 737         sl->master = dev;
 738         set_bit(W1_SLAVE_ACTIVE, &sl->flags);
 739
 740         memset(&msg, 0, sizeof(msg));
 741         memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));
 742         atomic_set(&sl->refcnt, 1);
 743         atomic_inc(&sl->master->refcnt);
 744         dev->slave_count++;
 745         dev_info(&dev->dev, "Attaching one wire slave %02x.%012llx crc %02x\n",
 746                   rn->family, (unsigned long long)rn->id, rn->crc);
 747
 748         /* slave modules need to be loaded in a context with unlocked mutex */
 749         mutex_unlock(&dev->mutex);
 750         request_module("w1-family-0x%02X", rn->family);
 751         mutex_lock(&dev->mutex);
 752
 753         spin_lock(&w1_flock);
 754         f = w1_family_registered(rn->family);
 755         if (!f) {
 756                 f= &w1_default_family;
 757                 dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n",
 758                           rn->family, rn->family,
 759                           (unsigned long long)rn->id, rn->crc);
 760         }
 761         __w1_family_get(f);
 762         spin_unlock(&w1_flock);
 763
 764         sl->family = f;
 765
 766         err = __w1_attach_slave_device(sl);
 767         if (err < 0) {
 768                 dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__,
 769                          sl->name);
 770                 dev->slave_count--;
 771                 w1_family_put(sl->family);
 772                 atomic_dec(&sl->master->refcnt);
 773                 kfree(sl);
 774                 return err;
 775         }
 776
 777         sl->ttl = dev->slave_ttl;
 778
 779         memcpy(msg.id.id, rn, sizeof(msg.id));
 780         msg.type = W1_SLAVE_ADD;
 781         w1_netlink_send(dev, &msg);
 782
 783         return 0;
 784 }
 785
 786 int w1_unref_slave(struct w1_slave *sl)
 787 {
 788         struct w1_master *dev = sl->master;
 789         int refcnt;
 790         mutex_lock(&dev->list_mutex);
 791         refcnt = atomic_sub_return(1, &sl->refcnt);
 792         if (refcnt == 0) {
 793                 struct w1_netlink_msg msg;
 794
 795                 dev_dbg(&sl->dev, "%s: detaching %s [%p].\n", __func__,
 796                         sl->name, sl);
 797
 798                 list_del(&sl->w1_slave_entry);
 799
 800                 memset(&msg, 0, sizeof(msg));
 801                 memcpy(msg.id.id, &sl->reg_num, sizeof(msg.id));
 802                 msg.type = W1_SLAVE_REMOVE;
 803                 w1_netlink_send(sl->master, &msg);
 804
 805                 w1_family_notify(BUS_NOTIFY_DEL_DEVICE, sl);
 806                 device_unregister(&sl->dev);
 807                 #ifdef DEBUG
 808                 memset(sl, 0, sizeof(*sl));
 809                 #endif
 810                 kfree(sl);
 811         }
 812         atomic_dec(&dev->refcnt);
 813         mutex_unlock(&dev->list_mutex);
 814         return refcnt;
 815 }
 816
 817 int w1_slave_detach(struct w1_slave *sl)
 818 {
 819         /* Only detach a slave once as it decreases the refcnt each time. */
 820         int destroy_now;
 821         mutex_lock(&sl->master->list_mutex);
 822         destroy_now = !test_bit(W1_SLAVE_DETACH, &sl->flags);
 823         set_bit(W1_SLAVE_DETACH, &sl->flags);
 824         mutex_unlock(&sl->master->list_mutex);
 825
 826         if (destroy_now)
 827                 destroy_now = !w1_unref_slave(sl);
 828         return destroy_now ? 0 : -EBUSY;
 829 }
 830
 831 struct w1_master *w1_search_master_id(u32 id)
 832 {
 833         struct w1_master *dev;
 834         int found = 0;
 835
 836         mutex_lock(&w1_mlock);
 837         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 838                 if (dev->id == id) {
 839                         found = 1;
 840                         atomic_inc(&dev->refcnt);
 841                         break;
 842                 }
 843         }
 844         mutex_unlock(&w1_mlock);
 845
 846         return (found)?dev:NULL;
 847 }
 848
 849 struct w1_slave *w1_search_slave(struct w1_reg_num *id)
 850 {
 851         struct w1_master *dev;
 852         struct w1_slave *sl = NULL;
 853         int found = 0;
 854
 855         mutex_lock(&w1_mlock);
 856         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 857                 mutex_lock(&dev->list_mutex);
 858                 list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
 859                         if (sl->reg_num.family == id->family &&
 860                                         sl->reg_num.id == id->id &&
 861                                         sl->reg_num.crc == id->crc) {
 862                                 found = 1;
 863                                 atomic_inc(&dev->refcnt);
 864                                 atomic_inc(&sl->refcnt);
 865                                 break;
 866                         }
 867                 }
 868                 mutex_unlock(&dev->list_mutex);
 869
 870                 if (found)
 871                         break;
 872         }
 873         mutex_unlock(&w1_mlock);
 874
 875         return (found)?sl:NULL;
 876 }
 877
 878 void w1_reconnect_slaves(struct w1_family *f, int attach)
 879 {
 880         struct w1_slave *sl, *sln;
 881         struct w1_master *dev;
 882
 883         mutex_lock(&w1_mlock);
 884         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 885                 dev_dbg(&dev->dev, "Reconnecting slaves in device %s "
 886                         "for family %02x.\n", dev->name, f->fid);
 887                 mutex_lock(&dev->mutex);
 888                 mutex_lock(&dev->list_mutex);
 889                 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 890                         /* If it is a new family, slaves with the default
 891                          * family driver and are that family will be
 892                          * connected.  If the family is going away, devices
 893                          * matching that family are reconneced.
 894                          */
 895                         if ((attach && sl->family->fid == W1_FAMILY_DEFAULT
 896                                 && sl->reg_num.family == f->fid) ||
 897                                 (!attach && sl->family->fid == f->fid)) {
 898                                 struct w1_reg_num rn;
 899
 900                                 mutex_unlock(&dev->list_mutex);
 901                                 memcpy(&rn, &sl->reg_num, sizeof(rn));
 902                                 /* If it was already in use let the automatic
 903                                  * scan pick it up again later.
 904                                  */
 905                                 if (!w1_slave_detach(sl))
 906                                         w1_attach_slave_device(dev, &rn);
 907                                 mutex_lock(&dev->list_mutex);
 908                         }
 909                 }
 910                 dev_dbg(&dev->dev, "Reconnecting slaves in device %s "
 911                         "has been finished.\n", dev->name);
 912                 mutex_unlock(&dev->list_mutex);
 913                 mutex_unlock(&dev->mutex);
 914         }
 915         mutex_unlock(&w1_mlock);
 916 }
 917
 918 static int w1_addr_crc_is_valid(struct w1_master *dev, u64 rn)
 919 {
 920         u64 rn_le = cpu_to_le64(rn);
 921         struct w1_reg_num *tmp = (struct w1_reg_num *)&rn;
 922         u8 crc;
 923
 924         crc = w1_calc_crc8((u8 *)&rn_le, 7);
 925
 926         /* quirk:
 927          *   DS28E04 (1w eeprom) has strapping pins to change
 928          *   address, but will not update the crc. So normal rules
 929          *   for consistent w1 addresses are violated. We test
 930          *   with the 7 LSBs of the address forced high.
 931          *
 932          *   (char*)&rn_le = { family, addr_lsb, ..., addr_msb, crc }.
 933          */
 934         if (crc != tmp->crc && tmp->family == W1_FAMILY_DS28E04) {
 935                 u64 corr_le = rn_le;
 936
 937                 ((u8 *)&corr_le)[1] |= 0x7f;
 938                 crc = w1_calc_crc8((u8 *)&corr_le, 7);
 939
 940                 dev_info(&dev->dev, "DS28E04 crc workaround on %02x.%012llx.%02x\n",
 941                         tmp->family, (unsigned long long)tmp->id, tmp->crc);
 942         }
 943
 944         if (crc != tmp->crc) {
 945                 dev_dbg(&dev->dev, "w1 addr crc mismatch: %02x.%012llx.%02x != 0x%02x.\n",
 946                         tmp->family, (unsigned long long)tmp->id, tmp->crc, crc);
 947                 return 0;
 948         }
 949         return 1;
 950 }
 951
 952 void w1_slave_found(struct w1_master *dev, u64 rn)
 953 {
 954         struct w1_slave *sl;
 955         struct w1_reg_num *tmp;
 956
 957         atomic_inc(&dev->refcnt);
 958
 959         tmp = (struct w1_reg_num *) &rn;
 960
 961         sl = w1_slave_search_device(dev, tmp);
 962         if (sl) {
 963                 set_bit(W1_SLAVE_ACTIVE, &sl->flags);
 964         } else {
 965                 if (rn && w1_addr_crc_is_valid(dev, rn))
 966                         w1_attach_slave_device(dev, tmp);
 967         }
 968
 969         atomic_dec(&dev->refcnt);
 970 }
 971
 972 /**
 973  * w1_search() - Performs a ROM Search & registers any devices found.
 974  * @dev: The master device to search
 975  * @search_type: W1_SEARCH to search all devices, or W1_ALARM_SEARCH
 976  * to return only devices in the alarmed state
 977  * @cb: Function to call when a device is found
 978  *
 979  * The 1-wire search is a simple binary tree search.
 980  * For each bit of the address, we read two bits and write one bit.
 981  * The bit written will put to sleep all devies that don't match that bit.
 982  * When the two reads differ, the direction choice is obvious.
 983  * When both bits are 0, we must choose a path to take.
 984  * When we can scan all 64 bits without having to choose a path, we are done.
 985  *
 986  * See "Application note 187 1-wire search algorithm" at www.maxim-ic.com
 987  *
 988  */
 989 void w1_search(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb)
 990 {
 991         u64 last_rn, rn, tmp64;
 992         int i, slave_count = 0;
 993         int last_zero, last_device;
 994         int search_bit, desc_bit;
 995         u8  triplet_ret = 0;
 996
 997         search_bit = 0;
 998         rn = dev->search_id;
 999         last_rn = 0;
1000         last_device = 0;
1001         last_zero = -1;
1002
1003         desc_bit = 64;
1004
1005         while ( !last_device && (slave_count++ < dev->max_slave_count) ) {
1006                 last_rn = rn;
1007                 rn = 0;
1008
1009                 /*
1010                  * Reset bus and all 1-wire device state machines
1011                  * so they can respond to our requests.
1012                  *
1013                  * Return 0 - device(s) present, 1 - no devices present.
1014                  */
1015                 mutex_lock(&dev->bus_mutex);
1016                 if (w1_reset_bus(dev)) {
1017                         mutex_unlock(&dev->bus_mutex);
1018                         dev_dbg(&dev->dev, "No devices present on the wire.\n");
1019                         break;
1020                 }
1021
1022                 /* Do fast search on single slave bus */
1023                 if (dev->max_slave_count == 1) {
1024                         int rv;
1025                         w1_write_8(dev, W1_READ_ROM);
1026                         rv = w1_read_block(dev, (u8 *)&rn, 8);
1027                         mutex_unlock(&dev->bus_mutex);
1028
1029                         if (rv == 8 && rn)
1030                                 cb(dev, rn);
1031
1032                         break;
1033                 }
1034
1035                 /* Start the search */
1036                 w1_write_8(dev, search_type);
1037                 for (i = 0; i < 64; ++i) {
1038                         /* Determine the direction/search bit */
1039                         if (i == desc_bit)
1040                                 search_bit = 1;   /* took the 0 path last time, so take the 1 path */
1041                         else if (i > desc_bit)
1042                                 search_bit = 0;   /* take the 0 path on the next branch */
1043                         else
1044                                 search_bit = ((last_rn >> i) & 0x1);
1045
1046                         /* Read two bits and write one bit */
1047                         triplet_ret = w1_triplet(dev, search_bit);
1048
1049                         /* quit if no device responded */
1050                         if ( (triplet_ret & 0x03) == 0x03 )
1051                                 break;
1052
1053                         /* If both directions were valid, and we took the 0 path... */
1054                         if (triplet_ret == 0)
1055                                 last_zero = i;
1056
1057                         /* extract the direction taken & update the device number */
1058                         tmp64 = (triplet_ret >> 2);
1059                         rn |= (tmp64 << i);
1060
1061                         if (test_bit(W1_ABORT_SEARCH, &dev->flags)) {
1062                                 mutex_unlock(&dev->bus_mutex);
1063                                 dev_dbg(&dev->dev, "Abort w1_search\n");
1064                                 return;
1065                         }
1066                 }
1067                 mutex_unlock(&dev->bus_mutex);
1068
1069                 if ( (triplet_ret & 0x03) != 0x03 ) {
1070                         if ((desc_bit == last_zero) || (last_zero < 0)) {
1071                                 last_device = 1;
1072                                 dev->search_id = 0;
1073                         } else {
1074                                 dev->search_id = rn;
1075                         }
1076                         desc_bit = last_zero;
1077                         cb(dev, rn);
1078                 }
1079
1080                 if (!last_device && slave_count == dev->max_slave_count &&
1081                         !test_bit(W1_WARN_MAX_COUNT, &dev->flags)) {
1082                         /* Only max_slave_count will be scanned in a search,
1083                          * but it will start where it left off next search
1084                          * until all ids are identified and then it will start
1085                          * over.  A continued search will report the previous
1086                          * last id as the first id (provided it is still on the
1087                          * bus).
1088                          */
1089                         dev_info(&dev->dev, "%s: max_slave_count %d reached, "
1090                                 "will continue next search.\n", __func__,
1091                                 dev->max_slave_count);
1092                         set_bit(W1_WARN_MAX_COUNT, &dev->flags);
1093                 }
1094         }
1095 }
1096
1097 void w1_search_process_cb(struct w1_master *dev, u8 search_type,
1098         w1_slave_found_callback cb)
1099 {
1100         struct w1_slave *sl, *sln;
1101
1102         mutex_lock(&dev->list_mutex);
1103         list_for_each_entry(sl, &dev->slist, w1_slave_entry)
1104                 clear_bit(W1_SLAVE_ACTIVE, &sl->flags);
1105         mutex_unlock(&dev->list_mutex);
1106
1107         w1_search_devices(dev, search_type, cb);
1108
1109         mutex_lock(&dev->list_mutex);
1110         list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
1111                 if (!test_bit(W1_SLAVE_ACTIVE, &sl->flags) && !--sl->ttl) {
1112                         mutex_unlock(&dev->list_mutex);
1113                         w1_slave_detach(sl);
1114                         mutex_lock(&dev->list_mutex);
1115                 }
1116                 else if (test_bit(W1_SLAVE_ACTIVE, &sl->flags))
1117                         sl->ttl = dev->slave_ttl;
1118         }
1119         mutex_unlock(&dev->list_mutex);
1120
1121         if (dev->search_count > 0)
1122                 dev->search_count--;
1123 }
1124
1125 static void w1_search_process(struct w1_master *dev, u8 search_type)
1126 {
1127         w1_search_process_cb(dev, search_type, w1_slave_found);
1128 }
1129
1130 /**
1131  * w1_process_callbacks() - execute each dev->async_list callback entry
1132  * @dev: w1_master device
1133  *
1134  * The w1 master list_mutex must be held.
1135  *
1136  * Return: 1 if there were commands to executed 0 otherwise
1137  */
1138 int w1_process_callbacks(struct w1_master *dev)
1139 {
1140         int ret = 0;
1141         struct w1_async_cmd *async_cmd, *async_n;
1142
1143         /* The list can be added to in another thread, loop until it is empty */
1144         while (!list_empty(&dev->async_list)) {
1145                 list_for_each_entry_safe(async_cmd, async_n, &dev->async_list,
1146                         async_entry) {
1147                         /* drop the lock, if it is a search it can take a long
1148                          * time */
1149                         mutex_unlock(&dev->list_mutex);
1150                         async_cmd->cb(dev, async_cmd);
1151                         ret = 1;
1152                         mutex_lock(&dev->list_mutex);
1153                 }
1154         }
1155         return ret;
1156 }
1157
1158 int w1_process(void *data)
1159 {
1160         struct w1_master *dev = (struct w1_master *) data;
1161         /* As long as w1_timeout is only set by a module parameter the sleep
1162          * time can be calculated in jiffies once.
1163          */
1164         const unsigned long jtime =
1165           usecs_to_jiffies(w1_timeout * 1000000 + w1_timeout_us);
1166         /* remainder if it woke up early */
1167         unsigned long jremain = 0;
1168
1169         for (;;) {
1170
1171                 if (!jremain && dev->search_count) {
1172                         mutex_lock(&dev->mutex);
1173                         w1_search_process(dev, W1_SEARCH);
1174                         mutex_unlock(&dev->mutex);
1175                 }
1176
1177                 mutex_lock(&dev->list_mutex);
1178                 /* Note, w1_process_callback drops the lock while processing,
1179                  * but locks it again before returning.
1180                  */
1181                 if (!w1_process_callbacks(dev) && jremain) {
1182                         /* a wake up is either to stop the thread, process
1183                          * callbacks, or search, it isn't process callbacks, so
1184                          * schedule a search.
1185                          */
1186                         jremain = 1;
1187                 }
1188
1189                 __set_current_state(TASK_INTERRUPTIBLE);
1190
1191                 /* hold list_mutex until after interruptible to prevent loosing
1192                  * the wakeup signal when async_cmd is added.
1193                  */
1194                 mutex_unlock(&dev->list_mutex);
1195
1196                 if (kthread_should_stop())
1197                         break;
1198
1199                 /* Only sleep when the search is active. */
1200                 if (dev->search_count) {
1201                         if (!jremain)
1202                                 jremain = jtime;
1203                         jremain = schedule_timeout(jremain);
1204                 }
1205                 else
1206                         schedule();
1207         }
1208
1209         atomic_dec(&dev->refcnt);
1210
1211         return 0;
1212 }
1213
1214 static int __init w1_init(void)
1215 {
1216         int retval;
1217
1218         pr_info("Driver for 1-wire Dallas network protocol.\n");
1219
1220         w1_init_netlink();
1221
1222         retval = bus_register(&w1_bus_type);
1223         if (retval) {
1224                 pr_err("Failed to register bus. err=%d.\n", retval);
1225                 goto err_out_exit_init;
1226         }
1227
1228         retval = driver_register(&w1_master_driver);
1229         if (retval) {
1230                 pr_err("Failed to register master driver. err=%d.\n",
1231                         retval);
1232                 goto err_out_bus_unregister;
1233         }
1234
1235         retval = driver_register(&w1_slave_driver);
1236         if (retval) {
1237                 pr_err("Failed to register slave driver. err=%d.\n",
1238                         retval);
1239                 goto err_out_master_unregister;
1240         }
1241
1242         return 0;
1243
1244 #if 0
1245 /* For undoing the slave register if there was a step after it. */
1246 err_out_slave_unregister:
1247         driver_unregister(&w1_slave_driver);
1248 #endif
1249
1250 err_out_master_unregister:
1251         driver_unregister(&w1_master_driver);
1252
1253 err_out_bus_unregister:
1254         bus_unregister(&w1_bus_type);
1255
1256 err_out_exit_init:
1257         return retval;
1258 }
1259
1260 static void __exit w1_fini(void)
1261 {
1262         struct w1_master *dev;
1263
1264         /* Set netlink removal messages and some cleanup */
1265         list_for_each_entry(dev, &w1_masters, w1_master_entry)
1266                 __w1_remove_master_device(dev);
1267
1268         w1_fini_netlink();
1269
1270         driver_unregister(&w1_slave_driver);
1271         driver_unregister(&w1_master_driver);
1272         bus_unregister(&w1_bus_type);
1273 }
1274
1275 module_init(w1_init);
1276 module_exit(w1_fini);
1277
1278 MODULE_AUTHOR("Evgeniy Polyakov <zbr@ioremap.net>");
1279 MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol.");
1280 MODULE_LICENSE("GPL");