usb: xhci-plat: properly handle probe deferral for devm_clk_get()
[linux/fpc-iii.git] / drivers / w1 / w1.c
blob89a78475173810944411f1a61fa8236d56cb75e1
1 /*
2 * w1.c
4 * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
22 #include <linux/delay.h>
23 #include <linux/kernel.h>
24 #include <linux/module.h>
25 #include <linux/moduleparam.h>
26 #include <linux/list.h>
27 #include <linux/interrupt.h>
28 #include <linux/spinlock.h>
29 #include <linux/timer.h>
30 #include <linux/device.h>
31 #include <linux/slab.h>
32 #include <linux/sched.h>
33 #include <linux/kthread.h>
34 #include <linux/freezer.h>
36 #include <linux/atomic.h>
38 #include "w1.h"
39 #include "w1_log.h"
40 #include "w1_int.h"
41 #include "w1_family.h"
42 #include "w1_netlink.h"
44 MODULE_LICENSE("GPL");
45 MODULE_AUTHOR("Evgeniy Polyakov <zbr@ioremap.net>");
46 MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol.");
48 static int w1_timeout = 10;
49 static int w1_timeout_us = 0;
50 int w1_max_slave_count = 64;
51 int w1_max_slave_ttl = 10;
53 module_param_named(timeout, w1_timeout, int, 0);
54 MODULE_PARM_DESC(timeout, "time in seconds between automatic slave searches");
55 module_param_named(timeout_us, w1_timeout_us, int, 0);
56 MODULE_PARM_DESC(timeout, "time in microseconds between automatic slave"
57 " searches");
58 /* A search stops when w1_max_slave_count devices have been found in that
59 * search. The next search will start over and detect the same set of devices
60 * on a static 1-wire bus. Memory is not allocated based on this number, just
61 * on the number of devices known to the kernel. Having a high number does not
62 * consume additional resources. As a special case, if there is only one
63 * device on the network and w1_max_slave_count is set to 1, the device id can
64 * be read directly skipping the normal slower search process.
66 module_param_named(max_slave_count, w1_max_slave_count, int, 0);
67 MODULE_PARM_DESC(max_slave_count,
68 "maximum number of slaves detected in a search");
69 module_param_named(slave_ttl, w1_max_slave_ttl, int, 0);
70 MODULE_PARM_DESC(slave_ttl,
71 "Number of searches not seeing a slave before it will be removed");
73 DEFINE_MUTEX(w1_mlock);
74 LIST_HEAD(w1_masters);
76 static int w1_master_match(struct device *dev, struct device_driver *drv)
78 return 1;
81 static int w1_master_probe(struct device *dev)
83 return -ENODEV;
86 static void w1_master_release(struct device *dev)
88 struct w1_master *md = dev_to_w1_master(dev);
90 dev_dbg(dev, "%s: Releasing %s.\n", __func__, md->name);
91 memset(md, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master));
92 kfree(md);
95 static void w1_slave_release(struct device *dev)
97 struct w1_slave *sl = dev_to_w1_slave(dev);
99 dev_dbg(dev, "%s: Releasing %s [%p]\n", __func__, sl->name, sl);
101 w1_family_put(sl->family);
102 sl->master->slave_count--;
105 static ssize_t name_show(struct device *dev, struct device_attribute *attr, char *buf)
107 struct w1_slave *sl = dev_to_w1_slave(dev);
109 return sprintf(buf, "%s\n", sl->name);
111 static DEVICE_ATTR_RO(name);
113 static ssize_t id_show(struct device *dev,
114 struct device_attribute *attr, char *buf)
116 struct w1_slave *sl = dev_to_w1_slave(dev);
117 ssize_t count = sizeof(sl->reg_num);
119 memcpy(buf, (u8 *)&sl->reg_num, count);
120 return count;
122 static DEVICE_ATTR_RO(id);
124 static struct attribute *w1_slave_attrs[] = {
125 &dev_attr_name.attr,
126 &dev_attr_id.attr,
127 NULL,
129 ATTRIBUTE_GROUPS(w1_slave);
131 /* Default family */
133 static ssize_t rw_write(struct file *filp, struct kobject *kobj,
134 struct bin_attribute *bin_attr, char *buf, loff_t off,
135 size_t count)
137 struct w1_slave *sl = kobj_to_w1_slave(kobj);
139 mutex_lock(&sl->master->mutex);
140 if (w1_reset_select_slave(sl)) {
141 count = 0;
142 goto out_up;
145 w1_write_block(sl->master, buf, count);
147 out_up:
148 mutex_unlock(&sl->master->mutex);
149 return count;
152 static ssize_t rw_read(struct file *filp, struct kobject *kobj,
153 struct bin_attribute *bin_attr, char *buf, loff_t off,
154 size_t count)
156 struct w1_slave *sl = kobj_to_w1_slave(kobj);
158 mutex_lock(&sl->master->mutex);
159 w1_read_block(sl->master, buf, count);
160 mutex_unlock(&sl->master->mutex);
161 return count;
164 static BIN_ATTR_RW(rw, PAGE_SIZE);
166 static struct bin_attribute *w1_slave_bin_attrs[] = {
167 &bin_attr_rw,
168 NULL,
171 static const struct attribute_group w1_slave_default_group = {
172 .bin_attrs = w1_slave_bin_attrs,
175 static const struct attribute_group *w1_slave_default_groups[] = {
176 &w1_slave_default_group,
177 NULL,
180 static struct w1_family_ops w1_default_fops = {
181 .groups = w1_slave_default_groups,
184 static struct w1_family w1_default_family = {
185 .fops = &w1_default_fops,
188 static int w1_uevent(struct device *dev, struct kobj_uevent_env *env);
190 static struct bus_type w1_bus_type = {
191 .name = "w1",
192 .match = w1_master_match,
193 .uevent = w1_uevent,
196 struct device_driver w1_master_driver = {
197 .name = "w1_master_driver",
198 .bus = &w1_bus_type,
199 .probe = w1_master_probe,
202 struct device w1_master_device = {
203 .parent = NULL,
204 .bus = &w1_bus_type,
205 .init_name = "w1 bus master",
206 .driver = &w1_master_driver,
207 .release = &w1_master_release
210 static struct device_driver w1_slave_driver = {
211 .name = "w1_slave_driver",
212 .bus = &w1_bus_type,
215 #if 0
216 struct device w1_slave_device = {
217 .parent = NULL,
218 .bus = &w1_bus_type,
219 .init_name = "w1 bus slave",
220 .driver = &w1_slave_driver,
221 .release = &w1_slave_release
223 #endif /* 0 */
225 static ssize_t w1_master_attribute_show_name(struct device *dev, struct device_attribute *attr, char *buf)
227 struct w1_master *md = dev_to_w1_master(dev);
228 ssize_t count;
230 mutex_lock(&md->mutex);
231 count = sprintf(buf, "%s\n", md->name);
232 mutex_unlock(&md->mutex);
234 return count;
237 static ssize_t w1_master_attribute_store_search(struct device * dev,
238 struct device_attribute *attr,
239 const char * buf, size_t count)
241 long tmp;
242 struct w1_master *md = dev_to_w1_master(dev);
243 int ret;
245 ret = kstrtol(buf, 0, &tmp);
246 if (ret)
247 return ret;
249 mutex_lock(&md->mutex);
250 md->search_count = tmp;
251 mutex_unlock(&md->mutex);
252 /* Only wake if it is going to be searching. */
253 if (tmp)
254 wake_up_process(md->thread);
256 return count;
259 static ssize_t w1_master_attribute_show_search(struct device *dev,
260 struct device_attribute *attr,
261 char *buf)
263 struct w1_master *md = dev_to_w1_master(dev);
264 ssize_t count;
266 mutex_lock(&md->mutex);
267 count = sprintf(buf, "%d\n", md->search_count);
268 mutex_unlock(&md->mutex);
270 return count;
273 static ssize_t w1_master_attribute_store_pullup(struct device *dev,
274 struct device_attribute *attr,
275 const char *buf, size_t count)
277 long tmp;
278 struct w1_master *md = dev_to_w1_master(dev);
279 int ret;
281 ret = kstrtol(buf, 0, &tmp);
282 if (ret)
283 return ret;
285 mutex_lock(&md->mutex);
286 md->enable_pullup = tmp;
287 mutex_unlock(&md->mutex);
289 return count;
292 static ssize_t w1_master_attribute_show_pullup(struct device *dev,
293 struct device_attribute *attr,
294 char *buf)
296 struct w1_master *md = dev_to_w1_master(dev);
297 ssize_t count;
299 mutex_lock(&md->mutex);
300 count = sprintf(buf, "%d\n", md->enable_pullup);
301 mutex_unlock(&md->mutex);
303 return count;
306 static ssize_t w1_master_attribute_show_pointer(struct device *dev, struct device_attribute *attr, char *buf)
308 struct w1_master *md = dev_to_w1_master(dev);
309 ssize_t count;
311 mutex_lock(&md->mutex);
312 count = sprintf(buf, "0x%p\n", md->bus_master);
313 mutex_unlock(&md->mutex);
314 return count;
317 static ssize_t w1_master_attribute_show_timeout(struct device *dev, struct device_attribute *attr, char *buf)
319 ssize_t count;
320 count = sprintf(buf, "%d\n", w1_timeout);
321 return count;
324 static ssize_t w1_master_attribute_show_timeout_us(struct device *dev,
325 struct device_attribute *attr, char *buf)
327 ssize_t count;
328 count = sprintf(buf, "%d\n", w1_timeout_us);
329 return count;
332 static ssize_t w1_master_attribute_store_max_slave_count(struct device *dev,
333 struct device_attribute *attr, const char *buf, size_t count)
335 int tmp;
336 struct w1_master *md = dev_to_w1_master(dev);
338 if (kstrtoint(buf, 0, &tmp) == -EINVAL || tmp < 1)
339 return -EINVAL;
341 mutex_lock(&md->mutex);
342 md->max_slave_count = tmp;
343 /* allow each time the max_slave_count is updated */
344 clear_bit(W1_WARN_MAX_COUNT, &md->flags);
345 mutex_unlock(&md->mutex);
347 return count;
350 static ssize_t w1_master_attribute_show_max_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
352 struct w1_master *md = dev_to_w1_master(dev);
353 ssize_t count;
355 mutex_lock(&md->mutex);
356 count = sprintf(buf, "%d\n", md->max_slave_count);
357 mutex_unlock(&md->mutex);
358 return count;
361 static ssize_t w1_master_attribute_show_attempts(struct device *dev, struct device_attribute *attr, char *buf)
363 struct w1_master *md = dev_to_w1_master(dev);
364 ssize_t count;
366 mutex_lock(&md->mutex);
367 count = sprintf(buf, "%lu\n", md->attempts);
368 mutex_unlock(&md->mutex);
369 return count;
372 static ssize_t w1_master_attribute_show_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
374 struct w1_master *md = dev_to_w1_master(dev);
375 ssize_t count;
377 mutex_lock(&md->mutex);
378 count = sprintf(buf, "%d\n", md->slave_count);
379 mutex_unlock(&md->mutex);
380 return count;
383 static ssize_t w1_master_attribute_show_slaves(struct device *dev,
384 struct device_attribute *attr, char *buf)
386 struct w1_master *md = dev_to_w1_master(dev);
387 int c = PAGE_SIZE;
388 struct list_head *ent, *n;
389 struct w1_slave *sl = NULL;
391 mutex_lock(&md->list_mutex);
393 list_for_each_safe(ent, n, &md->slist) {
394 sl = list_entry(ent, struct w1_slave, w1_slave_entry);
396 c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", sl->name);
398 if (!sl)
399 c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n");
401 mutex_unlock(&md->list_mutex);
403 return PAGE_SIZE - c;
406 static ssize_t w1_master_attribute_show_add(struct device *dev,
407 struct device_attribute *attr, char *buf)
409 int c = PAGE_SIZE;
410 c -= snprintf(buf+PAGE_SIZE - c, c,
411 "write device id xx-xxxxxxxxxxxx to add slave\n");
412 return PAGE_SIZE - c;
415 static int w1_atoreg_num(struct device *dev, const char *buf, size_t count,
416 struct w1_reg_num *rn)
418 unsigned int family;
419 unsigned long long id;
420 int i;
421 u64 rn64_le;
423 /* The CRC value isn't read from the user because the sysfs directory
424 * doesn't include it and most messages from the bus search don't
425 * print it either. It would be unreasonable for the user to then
426 * provide it.
428 const char *error_msg = "bad slave string format, expecting "
429 "ff-dddddddddddd\n";
431 if (buf[2] != '-') {
432 dev_err(dev, "%s", error_msg);
433 return -EINVAL;
435 i = sscanf(buf, "%02x-%012llx", &family, &id);
436 if (i != 2) {
437 dev_err(dev, "%s", error_msg);
438 return -EINVAL;
440 rn->family = family;
441 rn->id = id;
443 rn64_le = cpu_to_le64(*(u64 *)rn);
444 rn->crc = w1_calc_crc8((u8 *)&rn64_le, 7);
446 #if 0
447 dev_info(dev, "With CRC device is %02x.%012llx.%02x.\n",
448 rn->family, (unsigned long long)rn->id, rn->crc);
449 #endif
451 return 0;
454 /* Searches the slaves in the w1_master and returns a pointer or NULL.
455 * Note: must not hold list_mutex
457 struct w1_slave *w1_slave_search_device(struct w1_master *dev,
458 struct w1_reg_num *rn)
460 struct w1_slave *sl;
461 mutex_lock(&dev->list_mutex);
462 list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
463 if (sl->reg_num.family == rn->family &&
464 sl->reg_num.id == rn->id &&
465 sl->reg_num.crc == rn->crc) {
466 mutex_unlock(&dev->list_mutex);
467 return sl;
470 mutex_unlock(&dev->list_mutex);
471 return NULL;
474 static ssize_t w1_master_attribute_store_add(struct device *dev,
475 struct device_attribute *attr,
476 const char *buf, size_t count)
478 struct w1_master *md = dev_to_w1_master(dev);
479 struct w1_reg_num rn;
480 struct w1_slave *sl;
481 ssize_t result = count;
483 if (w1_atoreg_num(dev, buf, count, &rn))
484 return -EINVAL;
486 mutex_lock(&md->mutex);
487 sl = w1_slave_search_device(md, &rn);
488 /* It would be nice to do a targeted search one the one-wire bus
489 * for the new device to see if it is out there or not. But the
490 * current search doesn't support that.
492 if (sl) {
493 dev_info(dev, "Device %s already exists\n", sl->name);
494 result = -EINVAL;
495 } else {
496 w1_attach_slave_device(md, &rn);
498 mutex_unlock(&md->mutex);
500 return result;
503 static ssize_t w1_master_attribute_show_remove(struct device *dev,
504 struct device_attribute *attr, char *buf)
506 int c = PAGE_SIZE;
507 c -= snprintf(buf+PAGE_SIZE - c, c,
508 "write device id xx-xxxxxxxxxxxx to remove slave\n");
509 return PAGE_SIZE - c;
512 static ssize_t w1_master_attribute_store_remove(struct device *dev,
513 struct device_attribute *attr,
514 const char *buf, size_t count)
516 struct w1_master *md = dev_to_w1_master(dev);
517 struct w1_reg_num rn;
518 struct w1_slave *sl;
519 ssize_t result = count;
521 if (w1_atoreg_num(dev, buf, count, &rn))
522 return -EINVAL;
524 mutex_lock(&md->mutex);
525 sl = w1_slave_search_device(md, &rn);
526 if (sl) {
527 result = w1_slave_detach(sl);
528 /* refcnt 0 means it was detached in the call */
529 if (result == 0)
530 result = count;
531 } else {
532 dev_info(dev, "Device %02x-%012llx doesn't exists\n", rn.family,
533 (unsigned long long)rn.id);
534 result = -EINVAL;
536 mutex_unlock(&md->mutex);
538 return result;
541 #define W1_MASTER_ATTR_RO(_name, _mode) \
542 struct device_attribute w1_master_attribute_##_name = \
543 __ATTR(w1_master_##_name, _mode, \
544 w1_master_attribute_show_##_name, NULL)
546 #define W1_MASTER_ATTR_RW(_name, _mode) \
547 struct device_attribute w1_master_attribute_##_name = \
548 __ATTR(w1_master_##_name, _mode, \
549 w1_master_attribute_show_##_name, \
550 w1_master_attribute_store_##_name)
552 static W1_MASTER_ATTR_RO(name, S_IRUGO);
553 static W1_MASTER_ATTR_RO(slaves, S_IRUGO);
554 static W1_MASTER_ATTR_RO(slave_count, S_IRUGO);
555 static W1_MASTER_ATTR_RW(max_slave_count, S_IRUGO | S_IWUSR | S_IWGRP);
556 static W1_MASTER_ATTR_RO(attempts, S_IRUGO);
557 static W1_MASTER_ATTR_RO(timeout, S_IRUGO);
558 static W1_MASTER_ATTR_RO(timeout_us, S_IRUGO);
559 static W1_MASTER_ATTR_RO(pointer, S_IRUGO);
560 static W1_MASTER_ATTR_RW(search, S_IRUGO | S_IWUSR | S_IWGRP);
561 static W1_MASTER_ATTR_RW(pullup, S_IRUGO | S_IWUSR | S_IWGRP);
562 static W1_MASTER_ATTR_RW(add, S_IRUGO | S_IWUSR | S_IWGRP);
563 static W1_MASTER_ATTR_RW(remove, S_IRUGO | S_IWUSR | S_IWGRP);
565 static struct attribute *w1_master_default_attrs[] = {
566 &w1_master_attribute_name.attr,
567 &w1_master_attribute_slaves.attr,
568 &w1_master_attribute_slave_count.attr,
569 &w1_master_attribute_max_slave_count.attr,
570 &w1_master_attribute_attempts.attr,
571 &w1_master_attribute_timeout.attr,
572 &w1_master_attribute_timeout_us.attr,
573 &w1_master_attribute_pointer.attr,
574 &w1_master_attribute_search.attr,
575 &w1_master_attribute_pullup.attr,
576 &w1_master_attribute_add.attr,
577 &w1_master_attribute_remove.attr,
578 NULL
581 static struct attribute_group w1_master_defattr_group = {
582 .attrs = w1_master_default_attrs,
585 int w1_create_master_attributes(struct w1_master *master)
587 return sysfs_create_group(&master->dev.kobj, &w1_master_defattr_group);
590 void w1_destroy_master_attributes(struct w1_master *master)
592 sysfs_remove_group(&master->dev.kobj, &w1_master_defattr_group);
595 static int w1_uevent(struct device *dev, struct kobj_uevent_env *env)
597 struct w1_master *md = NULL;
598 struct w1_slave *sl = NULL;
599 char *event_owner, *name;
600 int err = 0;
602 if (dev->driver == &w1_master_driver) {
603 md = container_of(dev, struct w1_master, dev);
604 event_owner = "master";
605 name = md->name;
606 } else if (dev->driver == &w1_slave_driver) {
607 sl = container_of(dev, struct w1_slave, dev);
608 event_owner = "slave";
609 name = sl->name;
610 } else {
611 dev_dbg(dev, "Unknown event.\n");
612 return -EINVAL;
615 dev_dbg(dev, "Hotplug event for %s %s, bus_id=%s.\n",
616 event_owner, name, dev_name(dev));
618 if (dev->driver != &w1_slave_driver || !sl)
619 goto end;
621 err = add_uevent_var(env, "W1_FID=%02X", sl->reg_num.family);
622 if (err)
623 goto end;
625 err = add_uevent_var(env, "W1_SLAVE_ID=%024LX",
626 (unsigned long long)sl->reg_num.id);
627 end:
628 return err;
631 static int w1_family_notify(unsigned long action, struct w1_slave *sl)
633 struct w1_family_ops *fops;
634 int err;
636 fops = sl->family->fops;
638 if (!fops)
639 return 0;
641 switch (action) {
642 case BUS_NOTIFY_ADD_DEVICE:
643 /* if the family driver needs to initialize something... */
644 if (fops->add_slave) {
645 err = fops->add_slave(sl);
646 if (err < 0) {
647 dev_err(&sl->dev,
648 "add_slave() call failed. err=%d\n",
649 err);
650 return err;
653 if (fops->groups) {
654 err = sysfs_create_groups(&sl->dev.kobj, fops->groups);
655 if (err) {
656 dev_err(&sl->dev,
657 "sysfs group creation failed. err=%d\n",
658 err);
659 return err;
663 break;
664 case BUS_NOTIFY_DEL_DEVICE:
665 if (fops->remove_slave)
666 sl->family->fops->remove_slave(sl);
667 if (fops->groups)
668 sysfs_remove_groups(&sl->dev.kobj, fops->groups);
669 break;
671 return 0;
674 static int __w1_attach_slave_device(struct w1_slave *sl)
676 int err;
678 sl->dev.parent = &sl->master->dev;
679 sl->dev.driver = &w1_slave_driver;
680 sl->dev.bus = &w1_bus_type;
681 sl->dev.release = &w1_slave_release;
682 sl->dev.groups = w1_slave_groups;
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);
692 dev_dbg(&sl->dev, "%s: registering %s as %p.\n", __func__,
693 dev_name(&sl->dev), sl);
695 /* suppress for w1_family_notify before sending KOBJ_ADD */
696 dev_set_uevent_suppress(&sl->dev, true);
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 return err;
705 w1_family_notify(BUS_NOTIFY_ADD_DEVICE, sl);
707 dev_set_uevent_suppress(&sl->dev, false);
708 kobject_uevent(&sl->dev.kobj, KOBJ_ADD);
710 mutex_lock(&sl->master->list_mutex);
711 list_add_tail(&sl->w1_slave_entry, &sl->master->slist);
712 mutex_unlock(&sl->master->list_mutex);
714 return 0;
717 int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
719 struct w1_slave *sl;
720 struct w1_family *f;
721 int err;
722 struct w1_netlink_msg msg;
724 sl = kzalloc(sizeof(struct w1_slave), GFP_KERNEL);
725 if (!sl) {
726 dev_err(&dev->dev,
727 "%s: failed to allocate new slave device.\n",
728 __func__);
729 return -ENOMEM;
733 sl->owner = THIS_MODULE;
734 sl->master = dev;
735 set_bit(W1_SLAVE_ACTIVE, &sl->flags);
737 memset(&msg, 0, sizeof(msg));
738 memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));
739 atomic_set(&sl->refcnt, 1);
740 atomic_inc(&sl->master->refcnt);
742 /* slave modules need to be loaded in a context with unlocked mutex */
743 mutex_unlock(&dev->mutex);
744 request_module("w1-family-0x%02x", rn->family);
745 mutex_lock(&dev->mutex);
747 spin_lock(&w1_flock);
748 f = w1_family_registered(rn->family);
749 if (!f) {
750 f= &w1_default_family;
751 dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n",
752 rn->family, rn->family,
753 (unsigned long long)rn->id, rn->crc);
755 __w1_family_get(f);
756 spin_unlock(&w1_flock);
758 sl->family = f;
761 err = __w1_attach_slave_device(sl);
762 if (err < 0) {
763 dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__,
764 sl->name);
765 w1_family_put(sl->family);
766 kfree(sl);
767 return err;
770 sl->ttl = dev->slave_ttl;
771 dev->slave_count++;
773 memcpy(msg.id.id, rn, sizeof(msg.id));
774 msg.type = W1_SLAVE_ADD;
775 w1_netlink_send(dev, &msg);
777 return 0;
780 int w1_unref_slave(struct w1_slave *sl)
782 struct w1_master *dev = sl->master;
783 int refcnt;
784 mutex_lock(&dev->list_mutex);
785 refcnt = atomic_sub_return(1, &sl->refcnt);
786 if (refcnt == 0) {
787 struct w1_netlink_msg msg;
789 dev_dbg(&sl->dev, "%s: detaching %s [%p].\n", __func__,
790 sl->name, sl);
792 list_del(&sl->w1_slave_entry);
794 memset(&msg, 0, sizeof(msg));
795 memcpy(msg.id.id, &sl->reg_num, sizeof(msg.id));
796 msg.type = W1_SLAVE_REMOVE;
797 w1_netlink_send(sl->master, &msg);
799 w1_family_notify(BUS_NOTIFY_DEL_DEVICE, sl);
800 device_unregister(&sl->dev);
801 #ifdef DEBUG
802 memset(sl, 0, sizeof(*sl));
803 #endif
804 kfree(sl);
806 atomic_dec(&dev->refcnt);
807 mutex_unlock(&dev->list_mutex);
808 return refcnt;
811 int w1_slave_detach(struct w1_slave *sl)
813 /* Only detach a slave once as it decreases the refcnt each time. */
814 int destroy_now;
815 mutex_lock(&sl->master->list_mutex);
816 destroy_now = !test_bit(W1_SLAVE_DETACH, &sl->flags);
817 set_bit(W1_SLAVE_DETACH, &sl->flags);
818 mutex_unlock(&sl->master->list_mutex);
820 if (destroy_now)
821 destroy_now = !w1_unref_slave(sl);
822 return destroy_now ? 0 : -EBUSY;
825 struct w1_master *w1_search_master_id(u32 id)
827 struct w1_master *dev;
828 int found = 0;
830 mutex_lock(&w1_mlock);
831 list_for_each_entry(dev, &w1_masters, w1_master_entry) {
832 if (dev->id == id) {
833 found = 1;
834 atomic_inc(&dev->refcnt);
835 break;
838 mutex_unlock(&w1_mlock);
840 return (found)?dev:NULL;
843 struct w1_slave *w1_search_slave(struct w1_reg_num *id)
845 struct w1_master *dev;
846 struct w1_slave *sl = NULL;
847 int found = 0;
849 mutex_lock(&w1_mlock);
850 list_for_each_entry(dev, &w1_masters, w1_master_entry) {
851 mutex_lock(&dev->list_mutex);
852 list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
853 if (sl->reg_num.family == id->family &&
854 sl->reg_num.id == id->id &&
855 sl->reg_num.crc == id->crc) {
856 found = 1;
857 atomic_inc(&dev->refcnt);
858 atomic_inc(&sl->refcnt);
859 break;
862 mutex_unlock(&dev->list_mutex);
864 if (found)
865 break;
867 mutex_unlock(&w1_mlock);
869 return (found)?sl:NULL;
872 void w1_reconnect_slaves(struct w1_family *f, int attach)
874 struct w1_slave *sl, *sln;
875 struct w1_master *dev;
877 mutex_lock(&w1_mlock);
878 list_for_each_entry(dev, &w1_masters, w1_master_entry) {
879 dev_dbg(&dev->dev, "Reconnecting slaves in device %s "
880 "for family %02x.\n", dev->name, f->fid);
881 mutex_lock(&dev->mutex);
882 mutex_lock(&dev->list_mutex);
883 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
884 /* If it is a new family, slaves with the default
885 * family driver and are that family will be
886 * connected. If the family is going away, devices
887 * matching that family are reconneced.
889 if ((attach && sl->family->fid == W1_FAMILY_DEFAULT
890 && sl->reg_num.family == f->fid) ||
891 (!attach && sl->family->fid == f->fid)) {
892 struct w1_reg_num rn;
894 mutex_unlock(&dev->list_mutex);
895 memcpy(&rn, &sl->reg_num, sizeof(rn));
896 /* If it was already in use let the automatic
897 * scan pick it up again later.
899 if (!w1_slave_detach(sl))
900 w1_attach_slave_device(dev, &rn);
901 mutex_lock(&dev->list_mutex);
904 dev_dbg(&dev->dev, "Reconnecting slaves in device %s "
905 "has been finished.\n", dev->name);
906 mutex_unlock(&dev->list_mutex);
907 mutex_unlock(&dev->mutex);
909 mutex_unlock(&w1_mlock);
912 void w1_slave_found(struct w1_master *dev, u64 rn)
914 struct w1_slave *sl;
915 struct w1_reg_num *tmp;
916 u64 rn_le = cpu_to_le64(rn);
918 atomic_inc(&dev->refcnt);
920 tmp = (struct w1_reg_num *) &rn;
922 sl = w1_slave_search_device(dev, tmp);
923 if (sl) {
924 set_bit(W1_SLAVE_ACTIVE, &sl->flags);
925 } else {
926 if (rn && tmp->crc == w1_calc_crc8((u8 *)&rn_le, 7))
927 w1_attach_slave_device(dev, tmp);
930 atomic_dec(&dev->refcnt);
934 * w1_search() - Performs a ROM Search & registers any devices found.
935 * @dev: The master device to search
936 * @search_type: W1_SEARCH to search all devices, or W1_ALARM_SEARCH
937 * to return only devices in the alarmed state
938 * @cb: Function to call when a device is found
940 * The 1-wire search is a simple binary tree search.
941 * For each bit of the address, we read two bits and write one bit.
942 * The bit written will put to sleep all devies that don't match that bit.
943 * When the two reads differ, the direction choice is obvious.
944 * When both bits are 0, we must choose a path to take.
945 * When we can scan all 64 bits without having to choose a path, we are done.
947 * See "Application note 187 1-wire search algorithm" at www.maxim-ic.com
950 void w1_search(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb)
952 u64 last_rn, rn, tmp64;
953 int i, slave_count = 0;
954 int last_zero, last_device;
955 int search_bit, desc_bit;
956 u8 triplet_ret = 0;
958 search_bit = 0;
959 rn = dev->search_id;
960 last_rn = 0;
961 last_device = 0;
962 last_zero = -1;
964 desc_bit = 64;
966 while ( !last_device && (slave_count++ < dev->max_slave_count) ) {
967 last_rn = rn;
968 rn = 0;
971 * Reset bus and all 1-wire device state machines
972 * so they can respond to our requests.
974 * Return 0 - device(s) present, 1 - no devices present.
976 mutex_lock(&dev->bus_mutex);
977 if (w1_reset_bus(dev)) {
978 mutex_unlock(&dev->bus_mutex);
979 dev_dbg(&dev->dev, "No devices present on the wire.\n");
980 break;
983 /* Do fast search on single slave bus */
984 if (dev->max_slave_count == 1) {
985 int rv;
986 w1_write_8(dev, W1_READ_ROM);
987 rv = w1_read_block(dev, (u8 *)&rn, 8);
988 mutex_unlock(&dev->bus_mutex);
990 if (rv == 8 && rn)
991 cb(dev, rn);
993 break;
996 /* Start the search */
997 w1_write_8(dev, search_type);
998 for (i = 0; i < 64; ++i) {
999 /* Determine the direction/search bit */
1000 if (i == desc_bit)
1001 search_bit = 1; /* took the 0 path last time, so take the 1 path */
1002 else if (i > desc_bit)
1003 search_bit = 0; /* take the 0 path on the next branch */
1004 else
1005 search_bit = ((last_rn >> i) & 0x1);
1007 /* Read two bits and write one bit */
1008 triplet_ret = w1_triplet(dev, search_bit);
1010 /* quit if no device responded */
1011 if ( (triplet_ret & 0x03) == 0x03 )
1012 break;
1014 /* If both directions were valid, and we took the 0 path... */
1015 if (triplet_ret == 0)
1016 last_zero = i;
1018 /* extract the direction taken & update the device number */
1019 tmp64 = (triplet_ret >> 2);
1020 rn |= (tmp64 << i);
1022 if (test_bit(W1_ABORT_SEARCH, &dev->flags)) {
1023 mutex_unlock(&dev->bus_mutex);
1024 dev_dbg(&dev->dev, "Abort w1_search\n");
1025 return;
1028 mutex_unlock(&dev->bus_mutex);
1030 if ( (triplet_ret & 0x03) != 0x03 ) {
1031 if ((desc_bit == last_zero) || (last_zero < 0)) {
1032 last_device = 1;
1033 dev->search_id = 0;
1034 } else {
1035 dev->search_id = rn;
1037 desc_bit = last_zero;
1038 cb(dev, rn);
1041 if (!last_device && slave_count == dev->max_slave_count &&
1042 !test_bit(W1_WARN_MAX_COUNT, &dev->flags)) {
1043 /* Only max_slave_count will be scanned in a search,
1044 * but it will start where it left off next search
1045 * until all ids are identified and then it will start
1046 * over. A continued search will report the previous
1047 * last id as the first id (provided it is still on the
1048 * bus).
1050 dev_info(&dev->dev, "%s: max_slave_count %d reached, "
1051 "will continue next search.\n", __func__,
1052 dev->max_slave_count);
1053 set_bit(W1_WARN_MAX_COUNT, &dev->flags);
1058 void w1_search_process_cb(struct w1_master *dev, u8 search_type,
1059 w1_slave_found_callback cb)
1061 struct w1_slave *sl, *sln;
1063 mutex_lock(&dev->list_mutex);
1064 list_for_each_entry(sl, &dev->slist, w1_slave_entry)
1065 clear_bit(W1_SLAVE_ACTIVE, &sl->flags);
1066 mutex_unlock(&dev->list_mutex);
1068 w1_search_devices(dev, search_type, cb);
1070 mutex_lock(&dev->list_mutex);
1071 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
1072 if (!test_bit(W1_SLAVE_ACTIVE, &sl->flags) && !--sl->ttl) {
1073 mutex_unlock(&dev->list_mutex);
1074 w1_slave_detach(sl);
1075 mutex_lock(&dev->list_mutex);
1077 else if (test_bit(W1_SLAVE_ACTIVE, &sl->flags))
1078 sl->ttl = dev->slave_ttl;
1080 mutex_unlock(&dev->list_mutex);
1082 if (dev->search_count > 0)
1083 dev->search_count--;
1086 static void w1_search_process(struct w1_master *dev, u8 search_type)
1088 w1_search_process_cb(dev, search_type, w1_slave_found);
1092 * w1_process_callbacks() - execute each dev->async_list callback entry
1093 * @dev: w1_master device
1095 * The w1 master list_mutex must be held.
1097 * Return: 1 if there were commands to executed 0 otherwise
1099 int w1_process_callbacks(struct w1_master *dev)
1101 int ret = 0;
1102 struct w1_async_cmd *async_cmd, *async_n;
1104 /* The list can be added to in another thread, loop until it is empty */
1105 while (!list_empty(&dev->async_list)) {
1106 list_for_each_entry_safe(async_cmd, async_n, &dev->async_list,
1107 async_entry) {
1108 /* drop the lock, if it is a search it can take a long
1109 * time */
1110 mutex_unlock(&dev->list_mutex);
1111 async_cmd->cb(dev, async_cmd);
1112 ret = 1;
1113 mutex_lock(&dev->list_mutex);
1116 return ret;
1119 int w1_process(void *data)
1121 struct w1_master *dev = (struct w1_master *) data;
1122 /* As long as w1_timeout is only set by a module parameter the sleep
1123 * time can be calculated in jiffies once.
1125 const unsigned long jtime =
1126 usecs_to_jiffies(w1_timeout * 1000000 + w1_timeout_us);
1127 /* remainder if it woke up early */
1128 unsigned long jremain = 0;
1130 for (;;) {
1132 if (!jremain && dev->search_count) {
1133 mutex_lock(&dev->mutex);
1134 w1_search_process(dev, W1_SEARCH);
1135 mutex_unlock(&dev->mutex);
1138 mutex_lock(&dev->list_mutex);
1139 /* Note, w1_process_callback drops the lock while processing,
1140 * but locks it again before returning.
1142 if (!w1_process_callbacks(dev) && jremain) {
1143 /* a wake up is either to stop the thread, process
1144 * callbacks, or search, it isn't process callbacks, so
1145 * schedule a search.
1147 jremain = 1;
1150 __set_current_state(TASK_INTERRUPTIBLE);
1152 /* hold list_mutex until after interruptible to prevent loosing
1153 * the wakeup signal when async_cmd is added.
1155 mutex_unlock(&dev->list_mutex);
1157 if (kthread_should_stop())
1158 break;
1160 /* Only sleep when the search is active. */
1161 if (dev->search_count) {
1162 if (!jremain)
1163 jremain = jtime;
1164 jremain = schedule_timeout(jremain);
1166 else
1167 schedule();
1170 atomic_dec(&dev->refcnt);
1172 return 0;
1175 static int __init w1_init(void)
1177 int retval;
1179 pr_info("Driver for 1-wire Dallas network protocol.\n");
1181 w1_init_netlink();
1183 retval = bus_register(&w1_bus_type);
1184 if (retval) {
1185 pr_err("Failed to register bus. err=%d.\n", retval);
1186 goto err_out_exit_init;
1189 retval = driver_register(&w1_master_driver);
1190 if (retval) {
1191 pr_err("Failed to register master driver. err=%d.\n",
1192 retval);
1193 goto err_out_bus_unregister;
1196 retval = driver_register(&w1_slave_driver);
1197 if (retval) {
1198 pr_err("Failed to register slave driver. err=%d.\n",
1199 retval);
1200 goto err_out_master_unregister;
1203 return 0;
1205 #if 0
1206 /* For undoing the slave register if there was a step after it. */
1207 err_out_slave_unregister:
1208 driver_unregister(&w1_slave_driver);
1209 #endif
1211 err_out_master_unregister:
1212 driver_unregister(&w1_master_driver);
1214 err_out_bus_unregister:
1215 bus_unregister(&w1_bus_type);
1217 err_out_exit_init:
1218 return retval;
1221 static void __exit w1_fini(void)
1223 struct w1_master *dev;
1225 /* Set netlink removal messages and some cleanup */
1226 list_for_each_entry(dev, &w1_masters, w1_master_entry)
1227 __w1_remove_master_device(dev);
1229 w1_fini_netlink();
1231 driver_unregister(&w1_slave_driver);
1232 driver_unregister(&w1_master_driver);
1233 bus_unregister(&w1_bus_type);
1236 module_init(w1_init);
1237 module_exit(w1_fini);