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