w1.c

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