drivers/w1/w1.c

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