xref: /openbmc/linux/drivers/w1/slaves/w1_therm.c (revision ca481398)
1 /*
2  *	w1_therm.c
3  *
4  * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
5  *
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the therms 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.
11  *
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.
16  *
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
20  */
21 
22 #include <asm/types.h>
23 
24 #include <linux/kernel.h>
25 #include <linux/module.h>
26 #include <linux/moduleparam.h>
27 #include <linux/sched.h>
28 #include <linux/device.h>
29 #include <linux/types.h>
30 #include <linux/slab.h>
31 #include <linux/delay.h>
32 #include <linux/hwmon.h>
33 
34 #include <linux/w1.h>
35 
36 #define W1_THERM_DS18S20	0x10
37 #define W1_THERM_DS1822		0x22
38 #define W1_THERM_DS18B20	0x28
39 #define W1_THERM_DS1825		0x3B
40 #define W1_THERM_DS28EA00	0x42
41 
42 /* Allow the strong pullup to be disabled, but default to enabled.
43  * If it was disabled a parasite powered device might not get the require
44  * current to do a temperature conversion.  If it is enabled parasite powered
45  * devices have a better chance of getting the current required.
46  * In case the parasite power-detection is not working (seems to be the case
47  * for some DS18S20) the strong pullup can also be forced, regardless of the
48  * power state of the devices.
49  *
50  * Summary of options:
51  * - strong_pullup = 0	Disable strong pullup completely
52  * - strong_pullup = 1	Enable automatic strong pullup detection
53  * - strong_pullup = 2	Force strong pullup
54  */
55 static int w1_strong_pullup = 1;
56 module_param_named(strong_pullup, w1_strong_pullup, int, 0);
57 
58 struct w1_therm_family_data {
59 	uint8_t rom[9];
60 	atomic_t refcnt;
61 };
62 
63 struct therm_info {
64 	u8 rom[9];
65 	u8 crc;
66 	u8 verdict;
67 };
68 
69 /* return the address of the refcnt in the family data */
70 #define THERM_REFCNT(family_data) \
71 	(&((struct w1_therm_family_data *)family_data)->refcnt)
72 
73 static int w1_therm_add_slave(struct w1_slave *sl)
74 {
75 	sl->family_data = kzalloc(sizeof(struct w1_therm_family_data),
76 		GFP_KERNEL);
77 	if (!sl->family_data)
78 		return -ENOMEM;
79 	atomic_set(THERM_REFCNT(sl->family_data), 1);
80 	return 0;
81 }
82 
83 static void w1_therm_remove_slave(struct w1_slave *sl)
84 {
85 	int refcnt = atomic_sub_return(1, THERM_REFCNT(sl->family_data));
86 
87 	while (refcnt) {
88 		msleep(1000);
89 		refcnt = atomic_read(THERM_REFCNT(sl->family_data));
90 	}
91 	kfree(sl->family_data);
92 	sl->family_data = NULL;
93 }
94 
95 static ssize_t w1_slave_show(struct device *device,
96 	struct device_attribute *attr, char *buf);
97 
98 static ssize_t w1_slave_store(struct device *device,
99 	struct device_attribute *attr, const char *buf, size_t size);
100 
101 static ssize_t w1_seq_show(struct device *device,
102 	struct device_attribute *attr, char *buf);
103 
104 static DEVICE_ATTR_RW(w1_slave);
105 static DEVICE_ATTR_RO(w1_seq);
106 
107 static struct attribute *w1_therm_attrs[] = {
108 	&dev_attr_w1_slave.attr,
109 	NULL,
110 };
111 
112 static struct attribute *w1_ds28ea00_attrs[] = {
113 	&dev_attr_w1_slave.attr,
114 	&dev_attr_w1_seq.attr,
115 	NULL,
116 };
117 
118 ATTRIBUTE_GROUPS(w1_therm);
119 ATTRIBUTE_GROUPS(w1_ds28ea00);
120 
121 #if IS_REACHABLE(CONFIG_HWMON)
122 static int w1_read_temp(struct device *dev, u32 attr, int channel,
123 			long *val);
124 
125 static umode_t w1_is_visible(const void *_data, enum hwmon_sensor_types type,
126 			     u32 attr, int channel)
127 {
128 	return attr == hwmon_temp_input ? 0444 : 0;
129 }
130 
131 static int w1_read(struct device *dev, enum hwmon_sensor_types type,
132 		   u32 attr, int channel, long *val)
133 {
134 	switch (type) {
135 	case hwmon_temp:
136 		return w1_read_temp(dev, attr, channel, val);
137 	default:
138 		return -EOPNOTSUPP;
139 	}
140 }
141 
142 static const u32 w1_temp_config[] = {
143 	HWMON_T_INPUT,
144 	0
145 };
146 
147 static const struct hwmon_channel_info w1_temp = {
148 	.type = hwmon_temp,
149 	.config = w1_temp_config,
150 };
151 
152 static const struct hwmon_channel_info *w1_info[] = {
153 	&w1_temp,
154 	NULL
155 };
156 
157 static const struct hwmon_ops w1_hwmon_ops = {
158 	.is_visible = w1_is_visible,
159 	.read = w1_read,
160 };
161 
162 static const struct hwmon_chip_info w1_chip_info = {
163 	.ops = &w1_hwmon_ops,
164 	.info = w1_info,
165 };
166 #define W1_CHIPINFO	(&w1_chip_info)
167 #else
168 #define W1_CHIPINFO	NULL
169 #endif
170 
171 static struct w1_family_ops w1_therm_fops = {
172 	.add_slave	= w1_therm_add_slave,
173 	.remove_slave	= w1_therm_remove_slave,
174 	.groups		= w1_therm_groups,
175 	.chip_info	= W1_CHIPINFO,
176 };
177 
178 static struct w1_family_ops w1_ds28ea00_fops = {
179 	.add_slave	= w1_therm_add_slave,
180 	.remove_slave	= w1_therm_remove_slave,
181 	.groups		= w1_ds28ea00_groups,
182 	.chip_info	= W1_CHIPINFO,
183 };
184 
185 static struct w1_family w1_therm_family_DS18S20 = {
186 	.fid = W1_THERM_DS18S20,
187 	.fops = &w1_therm_fops,
188 };
189 
190 static struct w1_family w1_therm_family_DS18B20 = {
191 	.fid = W1_THERM_DS18B20,
192 	.fops = &w1_therm_fops,
193 };
194 
195 static struct w1_family w1_therm_family_DS1822 = {
196 	.fid = W1_THERM_DS1822,
197 	.fops = &w1_therm_fops,
198 };
199 
200 static struct w1_family w1_therm_family_DS28EA00 = {
201 	.fid = W1_THERM_DS28EA00,
202 	.fops = &w1_ds28ea00_fops,
203 };
204 
205 static struct w1_family w1_therm_family_DS1825 = {
206 	.fid = W1_THERM_DS1825,
207 	.fops = &w1_therm_fops,
208 };
209 
210 struct w1_therm_family_converter {
211 	u8			broken;
212 	u16			reserved;
213 	struct w1_family	*f;
214 	int			(*convert)(u8 rom[9]);
215 	int			(*precision)(struct device *device, int val);
216 	int			(*eeprom)(struct device *device);
217 };
218 
219 /* write configuration to eeprom */
220 static inline int w1_therm_eeprom(struct device *device);
221 
222 /* Set precision for conversion */
223 static inline int w1_DS18B20_precision(struct device *device, int val);
224 static inline int w1_DS18S20_precision(struct device *device, int val);
225 
226 /* The return value is millidegrees Centigrade. */
227 static inline int w1_DS18B20_convert_temp(u8 rom[9]);
228 static inline int w1_DS18S20_convert_temp(u8 rom[9]);
229 
230 static struct w1_therm_family_converter w1_therm_families[] = {
231 	{
232 		.f		= &w1_therm_family_DS18S20,
233 		.convert	= w1_DS18S20_convert_temp,
234 		.precision	= w1_DS18S20_precision,
235 		.eeprom		= w1_therm_eeprom
236 	},
237 	{
238 		.f		= &w1_therm_family_DS1822,
239 		.convert	= w1_DS18B20_convert_temp,
240 		.precision	= w1_DS18S20_precision,
241 		.eeprom		= w1_therm_eeprom
242 	},
243 	{
244 		.f		= &w1_therm_family_DS18B20,
245 		.convert	= w1_DS18B20_convert_temp,
246 		.precision	= w1_DS18B20_precision,
247 		.eeprom		= w1_therm_eeprom
248 	},
249 	{
250 		.f		= &w1_therm_family_DS28EA00,
251 		.convert	= w1_DS18B20_convert_temp,
252 		.precision	= w1_DS18S20_precision,
253 		.eeprom		= w1_therm_eeprom
254 	},
255 	{
256 		.f		= &w1_therm_family_DS1825,
257 		.convert	= w1_DS18B20_convert_temp,
258 		.precision	= w1_DS18S20_precision,
259 		.eeprom		= w1_therm_eeprom
260 	}
261 };
262 
263 static inline int w1_therm_eeprom(struct device *device)
264 {
265 	struct w1_slave *sl = dev_to_w1_slave(device);
266 	struct w1_master *dev = sl->master;
267 	u8 rom[9], external_power;
268 	int ret, max_trying = 10;
269 	u8 *family_data = sl->family_data;
270 
271 	ret = mutex_lock_interruptible(&dev->bus_mutex);
272 	if (ret != 0)
273 		goto post_unlock;
274 
275 	if (!sl->family_data) {
276 		ret = -ENODEV;
277 		goto pre_unlock;
278 	}
279 
280 	/* prevent the slave from going away in sleep */
281 	atomic_inc(THERM_REFCNT(family_data));
282 	memset(rom, 0, sizeof(rom));
283 
284 	while (max_trying--) {
285 		if (!w1_reset_select_slave(sl)) {
286 			unsigned int tm = 10;
287 			unsigned long sleep_rem;
288 
289 			/* check if in parasite mode */
290 			w1_write_8(dev, W1_READ_PSUPPLY);
291 			external_power = w1_read_8(dev);
292 
293 			if (w1_reset_select_slave(sl))
294 				continue;
295 
296 			/* 10ms strong pullup/delay after the copy command */
297 			if (w1_strong_pullup == 2 ||
298 			    (!external_power && w1_strong_pullup))
299 				w1_next_pullup(dev, tm);
300 
301 			w1_write_8(dev, W1_COPY_SCRATCHPAD);
302 
303 			if (external_power) {
304 				mutex_unlock(&dev->bus_mutex);
305 
306 				sleep_rem = msleep_interruptible(tm);
307 				if (sleep_rem != 0) {
308 					ret = -EINTR;
309 					goto post_unlock;
310 				}
311 
312 				ret = mutex_lock_interruptible(&dev->bus_mutex);
313 				if (ret != 0)
314 					goto post_unlock;
315 			} else if (!w1_strong_pullup) {
316 				sleep_rem = msleep_interruptible(tm);
317 				if (sleep_rem != 0) {
318 					ret = -EINTR;
319 					goto pre_unlock;
320 				}
321 			}
322 
323 			break;
324 		}
325 	}
326 
327 pre_unlock:
328 	mutex_unlock(&dev->bus_mutex);
329 
330 post_unlock:
331 	atomic_dec(THERM_REFCNT(family_data));
332 	return ret;
333 }
334 
335 /* DS18S20 does not feature configuration register */
336 static inline int w1_DS18S20_precision(struct device *device, int val)
337 {
338 	return 0;
339 }
340 
341 static inline int w1_DS18B20_precision(struct device *device, int val)
342 {
343 	struct w1_slave *sl = dev_to_w1_slave(device);
344 	struct w1_master *dev = sl->master;
345 	u8 rom[9], crc;
346 	int ret, max_trying = 10;
347 	u8 *family_data = sl->family_data;
348 	uint8_t precision_bits;
349 	uint8_t mask = 0x60;
350 
351 	if (val > 12 || val < 9) {
352 		pr_warn("Unsupported precision\n");
353 		return -1;
354 	}
355 
356 	ret = mutex_lock_interruptible(&dev->bus_mutex);
357 	if (ret != 0)
358 		goto post_unlock;
359 
360 	if (!sl->family_data) {
361 		ret = -ENODEV;
362 		goto pre_unlock;
363 	}
364 
365 	/* prevent the slave from going away in sleep */
366 	atomic_inc(THERM_REFCNT(family_data));
367 	memset(rom, 0, sizeof(rom));
368 
369 	/* translate precision to bitmask (see datasheet page 9) */
370 	switch (val) {
371 	case 9:
372 		precision_bits = 0x00;
373 		break;
374 	case 10:
375 		precision_bits = 0x20;
376 		break;
377 	case 11:
378 		precision_bits = 0x40;
379 		break;
380 	case 12:
381 	default:
382 		precision_bits = 0x60;
383 		break;
384 	}
385 
386 	while (max_trying--) {
387 		crc = 0;
388 
389 		if (!w1_reset_select_slave(sl)) {
390 			int count = 0;
391 
392 			/* read values to only alter precision bits */
393 			w1_write_8(dev, W1_READ_SCRATCHPAD);
394 			count = w1_read_block(dev, rom, 9);
395 			if (count != 9)
396 				dev_warn(device, "w1_read_block() returned %u instead of 9.\n",	count);
397 
398 			crc = w1_calc_crc8(rom, 8);
399 			if (rom[8] == crc) {
400 				rom[4] = (rom[4] & ~mask) | (precision_bits & mask);
401 
402 				if (!w1_reset_select_slave(sl)) {
403 					w1_write_8(dev, W1_WRITE_SCRATCHPAD);
404 					w1_write_8(dev, rom[2]);
405 					w1_write_8(dev, rom[3]);
406 					w1_write_8(dev, rom[4]);
407 
408 					break;
409 				}
410 			}
411 		}
412 	}
413 
414 pre_unlock:
415 	mutex_unlock(&dev->bus_mutex);
416 
417 post_unlock:
418 	atomic_dec(THERM_REFCNT(family_data));
419 	return ret;
420 }
421 
422 static inline int w1_DS18B20_convert_temp(u8 rom[9])
423 {
424 	s16 t = le16_to_cpup((__le16 *)rom);
425 
426 	return t*1000/16;
427 }
428 
429 static inline int w1_DS18S20_convert_temp(u8 rom[9])
430 {
431 	int t, h;
432 
433 	if (!rom[7])
434 		return 0;
435 
436 	if (rom[1] == 0)
437 		t = ((s32)rom[0] >> 1)*1000;
438 	else
439 		t = 1000*(-1*(s32)(0x100-rom[0]) >> 1);
440 
441 	t -= 250;
442 	h = 1000*((s32)rom[7] - (s32)rom[6]);
443 	h /= (s32)rom[7];
444 	t += h;
445 
446 	return t;
447 }
448 
449 static inline int w1_convert_temp(u8 rom[9], u8 fid)
450 {
451 	int i;
452 
453 	for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i)
454 		if (w1_therm_families[i].f->fid == fid)
455 			return w1_therm_families[i].convert(rom);
456 
457 	return 0;
458 }
459 
460 static ssize_t w1_slave_store(struct device *device,
461 			      struct device_attribute *attr, const char *buf,
462 			      size_t size)
463 {
464 	int val, ret;
465 	struct w1_slave *sl = dev_to_w1_slave(device);
466 	int i;
467 
468 	ret = kstrtoint(buf, 0, &val);
469 	if (ret)
470 		return ret;
471 
472 	for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i) {
473 		if (w1_therm_families[i].f->fid == sl->family->fid) {
474 			/* zero value indicates to write current configuration to eeprom */
475 			if (val == 0)
476 				ret = w1_therm_families[i].eeprom(device);
477 			else
478 				ret = w1_therm_families[i].precision(device, val);
479 			break;
480 		}
481 	}
482 	return ret ? : size;
483 }
484 
485 static ssize_t read_therm(struct device *device,
486 			  struct w1_slave *sl, struct therm_info *info)
487 {
488 	struct w1_master *dev = sl->master;
489 	u8 external_power;
490 	int ret, max_trying = 10;
491 	u8 *family_data = sl->family_data;
492 
493 	ret = mutex_lock_interruptible(&dev->bus_mutex);
494 	if (ret != 0)
495 		goto error;
496 
497 	if (!family_data) {
498 		ret = -ENODEV;
499 		goto mt_unlock;
500 	}
501 
502 	/* prevent the slave from going away in sleep */
503 	atomic_inc(THERM_REFCNT(family_data));
504 	memset(info->rom, 0, sizeof(info->rom));
505 
506 	while (max_trying--) {
507 
508 		info->verdict = 0;
509 		info->crc = 0;
510 
511 		if (!w1_reset_select_slave(sl)) {
512 			int count = 0;
513 			unsigned int tm = 750;
514 			unsigned long sleep_rem;
515 
516 			w1_write_8(dev, W1_READ_PSUPPLY);
517 			external_power = w1_read_8(dev);
518 
519 			if (w1_reset_select_slave(sl))
520 				continue;
521 
522 			/* 750ms strong pullup (or delay) after the convert */
523 			if (w1_strong_pullup == 2 ||
524 					(!external_power && w1_strong_pullup))
525 				w1_next_pullup(dev, tm);
526 
527 			w1_write_8(dev, W1_CONVERT_TEMP);
528 
529 			if (external_power) {
530 				mutex_unlock(&dev->bus_mutex);
531 
532 				sleep_rem = msleep_interruptible(tm);
533 				if (sleep_rem != 0) {
534 					ret = -EINTR;
535 					goto dec_refcnt;
536 				}
537 
538 				ret = mutex_lock_interruptible(&dev->bus_mutex);
539 				if (ret != 0)
540 					goto dec_refcnt;
541 			} else if (!w1_strong_pullup) {
542 				sleep_rem = msleep_interruptible(tm);
543 				if (sleep_rem != 0) {
544 					ret = -EINTR;
545 					goto dec_refcnt;
546 				}
547 			}
548 
549 			if (!w1_reset_select_slave(sl)) {
550 
551 				w1_write_8(dev, W1_READ_SCRATCHPAD);
552 				count = w1_read_block(dev, info->rom, 9);
553 				if (count != 9) {
554 					dev_warn(device, "w1_read_block() "
555 						"returned %u instead of 9.\n",
556 						count);
557 				}
558 
559 				info->crc = w1_calc_crc8(info->rom, 8);
560 
561 				if (info->rom[8] == info->crc)
562 					info->verdict = 1;
563 			}
564 		}
565 
566 		if (info->verdict)
567 			break;
568 	}
569 
570 dec_refcnt:
571 	atomic_dec(THERM_REFCNT(family_data));
572 mt_unlock:
573 	mutex_unlock(&dev->bus_mutex);
574 error:
575 	return ret;
576 }
577 
578 static ssize_t w1_slave_show(struct device *device,
579 			     struct device_attribute *attr, char *buf)
580 {
581 	struct w1_slave *sl = dev_to_w1_slave(device);
582 	struct therm_info info;
583 	u8 *family_data = sl->family_data;
584 	int ret, i;
585 	ssize_t c = PAGE_SIZE;
586 	u8 fid = sl->family->fid;
587 
588 	ret = read_therm(device, sl, &info);
589 	if (ret)
590 		return ret;
591 
592 	for (i = 0; i < 9; ++i)
593 		c -= snprintf(buf + PAGE_SIZE - c, c, "%02x ", info.rom[i]);
594 	c -= snprintf(buf + PAGE_SIZE - c, c, ": crc=%02x %s\n",
595 		      info.crc, (info.verdict) ? "YES" : "NO");
596 	if (info.verdict)
597 		memcpy(family_data, info.rom, sizeof(info.rom));
598 	else
599 		dev_warn(device, "Read failed CRC check\n");
600 
601 	for (i = 0; i < 9; ++i)
602 		c -= snprintf(buf + PAGE_SIZE - c, c, "%02x ",
603 			      ((u8 *)family_data)[i]);
604 
605 	c -= snprintf(buf + PAGE_SIZE - c, c, "t=%d\n",
606 			w1_convert_temp(info.rom, fid));
607 	ret = PAGE_SIZE - c;
608 	return ret;
609 }
610 
611 #if IS_REACHABLE(CONFIG_HWMON)
612 static int w1_read_temp(struct device *device, u32 attr, int channel,
613 			long *val)
614 {
615 	struct w1_slave *sl = dev_get_drvdata(device);
616 	struct therm_info info;
617 	u8 fid = sl->family->fid;
618 	int ret;
619 
620 	switch (attr) {
621 	case hwmon_temp_input:
622 		ret = read_therm(device, sl, &info);
623 		if (ret)
624 			return ret;
625 
626 		if (!info.verdict) {
627 			ret = -EIO;
628 			return ret;
629 		}
630 
631 		*val = w1_convert_temp(info.rom, fid);
632 		ret = 0;
633 		break;
634 	default:
635 		ret = -EOPNOTSUPP;
636 		break;
637 	}
638 
639 	return ret;
640 }
641 #endif
642 
643 #define W1_42_CHAIN	0x99
644 #define W1_42_CHAIN_OFF	0x3C
645 #define W1_42_CHAIN_OFF_INV	0xC3
646 #define W1_42_CHAIN_ON	0x5A
647 #define W1_42_CHAIN_ON_INV	0xA5
648 #define W1_42_CHAIN_DONE 0x96
649 #define W1_42_CHAIN_DONE_INV 0x69
650 #define W1_42_COND_READ	0x0F
651 #define W1_42_SUCCESS_CONFIRM_BYTE 0xAA
652 #define W1_42_FINISHED_BYTE 0xFF
653 static ssize_t w1_seq_show(struct device *device,
654 	struct device_attribute *attr, char *buf)
655 {
656 	struct w1_slave *sl = dev_to_w1_slave(device);
657 	ssize_t c = PAGE_SIZE;
658 	int rv;
659 	int i;
660 	u8 ack;
661 	u64 rn;
662 	struct w1_reg_num *reg_num;
663 	int seq = 0;
664 
665 	mutex_lock(&sl->master->bus_mutex);
666 	/* Place all devices in CHAIN state */
667 	if (w1_reset_bus(sl->master))
668 		goto error;
669 	w1_write_8(sl->master, W1_SKIP_ROM);
670 	w1_write_8(sl->master, W1_42_CHAIN);
671 	w1_write_8(sl->master, W1_42_CHAIN_ON);
672 	w1_write_8(sl->master, W1_42_CHAIN_ON_INV);
673 	msleep(sl->master->pullup_duration);
674 
675 	/* check for acknowledgment */
676 	ack = w1_read_8(sl->master);
677 	if (ack != W1_42_SUCCESS_CONFIRM_BYTE)
678 		goto error;
679 
680 	/* In case the bus fails to send 0xFF, limit*/
681 	for (i = 0; i <= 64; i++) {
682 		if (w1_reset_bus(sl->master))
683 			goto error;
684 
685 		w1_write_8(sl->master, W1_42_COND_READ);
686 		rv = w1_read_block(sl->master, (u8 *)&rn, 8);
687 		reg_num = (struct w1_reg_num *) &rn;
688 		if (reg_num->family == W1_42_FINISHED_BYTE)
689 			break;
690 		if (sl->reg_num.id == reg_num->id)
691 			seq = i;
692 
693 		w1_write_8(sl->master, W1_42_CHAIN);
694 		w1_write_8(sl->master, W1_42_CHAIN_DONE);
695 		w1_write_8(sl->master, W1_42_CHAIN_DONE_INV);
696 		w1_read_block(sl->master, &ack, sizeof(ack));
697 
698 		/* check for acknowledgment */
699 		ack = w1_read_8(sl->master);
700 		if (ack != W1_42_SUCCESS_CONFIRM_BYTE)
701 			goto error;
702 
703 	}
704 
705 	/* Exit from CHAIN state */
706 	if (w1_reset_bus(sl->master))
707 		goto error;
708 	w1_write_8(sl->master, W1_SKIP_ROM);
709 	w1_write_8(sl->master, W1_42_CHAIN);
710 	w1_write_8(sl->master, W1_42_CHAIN_OFF);
711 	w1_write_8(sl->master, W1_42_CHAIN_OFF_INV);
712 
713 	/* check for acknowledgment */
714 	ack = w1_read_8(sl->master);
715 	if (ack != W1_42_SUCCESS_CONFIRM_BYTE)
716 		goto error;
717 	mutex_unlock(&sl->master->bus_mutex);
718 
719 	c -= snprintf(buf + PAGE_SIZE - c, c, "%d\n", seq);
720 	return PAGE_SIZE - c;
721 error:
722 	mutex_unlock(&sl->master->bus_mutex);
723 	return -EIO;
724 }
725 
726 static int __init w1_therm_init(void)
727 {
728 	int err, i;
729 
730 	for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i) {
731 		err = w1_register_family(w1_therm_families[i].f);
732 		if (err)
733 			w1_therm_families[i].broken = 1;
734 	}
735 
736 	return 0;
737 }
738 
739 static void __exit w1_therm_fini(void)
740 {
741 	int i;
742 
743 	for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i)
744 		if (!w1_therm_families[i].broken)
745 			w1_unregister_family(w1_therm_families[i].f);
746 }
747 
748 module_init(w1_therm_init);
749 module_exit(w1_therm_fini);
750 
751 MODULE_AUTHOR("Evgeniy Polyakov <zbr@ioremap.net>");
752 MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol, temperature family.");
753 MODULE_LICENSE("GPL");
754 MODULE_ALIAS("w1-family-" __stringify(W1_THERM_DS18S20));
755 MODULE_ALIAS("w1-family-" __stringify(W1_THERM_DS1822));
756 MODULE_ALIAS("w1-family-" __stringify(W1_THERM_DS18B20));
757 MODULE_ALIAS("w1-family-" __stringify(W1_THERM_DS1825));
758 MODULE_ALIAS("w1-family-" __stringify(W1_THERM_DS28EA00));
759