drivers/w1/w1.c

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