xref: /openbmc/linux/drivers/hwmon/hwmon.c (revision 9b26947ce5b6a6d5f260d9564195e8971cc9713d) 
1 /*
2  * hwmon.c - part of lm_sensors, Linux kernel modules for hardware monitoring
3  *
4  * This file defines the sysfs class "hwmon", for use by sensors drivers.
5  *
6  * Copyright (C) 2005 Mark M. Hoffman <mhoffman@lightlink.com>
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License as published by
10  * the Free Software Foundation; version 2 of the License.
11  */
12 
13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
14 
15 #include <linux/bitops.h>
16 #include <linux/device.h>
17 #include <linux/err.h>
18 #include <linux/gfp.h>
19 #include <linux/hwmon.h>
20 #include <linux/idr.h>
21 #include <linux/module.h>
22 #include <linux/pci.h>
23 #include <linux/slab.h>
24 #include <linux/string.h>
25 #include <linux/thermal.h>
26 
27 #define HWMON_ID_PREFIX "hwmon"
28 #define HWMON_ID_FORMAT HWMON_ID_PREFIX "%d"
29 
30 struct hwmon_device {
31 	const char *name;
32 	struct device dev;
33 	const struct hwmon_chip_info *chip;
34 
35 	struct attribute_group group;
36 	const struct attribute_group **groups;
37 };
38 
39 #define to_hwmon_device(d) container_of(d, struct hwmon_device, dev)
40 
41 struct hwmon_device_attribute {
42 	struct device_attribute dev_attr;
43 	const struct hwmon_ops *ops;
44 	enum hwmon_sensor_types type;
45 	u32 attr;
46 	int index;
47 };
48 
49 #define to_hwmon_attr(d) \
50 	container_of(d, struct hwmon_device_attribute, dev_attr)
51 
52 /*
53  * Thermal zone information
54  * In addition to the reference to the hwmon device,
55  * also provides the sensor index.
56  */
57 struct hwmon_thermal_data {
58 	struct hwmon_device *hwdev;	/* Reference to hwmon device */
59 	int index;			/* sensor index */
60 };
61 
62 static ssize_t
63 show_name(struct device *dev, struct device_attribute *attr, char *buf)
64 {
65 	return sprintf(buf, "%s\n", to_hwmon_device(dev)->name);
66 }
67 static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
68 
69 static struct attribute *hwmon_dev_attrs[] = {
70 	&dev_attr_name.attr,
71 	NULL
72 };
73 
74 static umode_t hwmon_dev_name_is_visible(struct kobject *kobj,
75 					 struct attribute *attr, int n)
76 {
77 	struct device *dev = container_of(kobj, struct device, kobj);
78 
79 	if (to_hwmon_device(dev)->name == NULL)
80 		return 0;
81 
82 	return attr->mode;
83 }
84 
85 static struct attribute_group hwmon_dev_attr_group = {
86 	.attrs		= hwmon_dev_attrs,
87 	.is_visible	= hwmon_dev_name_is_visible,
88 };
89 
90 static const struct attribute_group *hwmon_dev_attr_groups[] = {
91 	&hwmon_dev_attr_group,
92 	NULL
93 };
94 
95 static void hwmon_dev_release(struct device *dev)
96 {
97 	kfree(to_hwmon_device(dev));
98 }
99 
100 static struct class hwmon_class = {
101 	.name = "hwmon",
102 	.owner = THIS_MODULE,
103 	.dev_groups = hwmon_dev_attr_groups,
104 	.dev_release = hwmon_dev_release,
105 };
106 
107 static DEFINE_IDA(hwmon_ida);
108 
109 /* Thermal zone handling */
110 
111 #if IS_REACHABLE(CONFIG_THERMAL) && defined(CONFIG_THERMAL_OF)
112 static int hwmon_thermal_get_temp(void *data, int *temp)
113 {
114 	struct hwmon_thermal_data *tdata = data;
115 	struct hwmon_device *hwdev = tdata->hwdev;
116 	int ret;
117 	long t;
118 
119 	ret = hwdev->chip->ops->read(&hwdev->dev, hwmon_temp, hwmon_temp_input,
120 				     tdata->index, &t);
121 	if (ret < 0)
122 		return ret;
123 
124 	*temp = t;
125 
126 	return 0;
127 }
128 
129 static struct thermal_zone_of_device_ops hwmon_thermal_ops = {
130 	.get_temp = hwmon_thermal_get_temp,
131 };
132 
133 static int hwmon_thermal_add_sensor(struct device *dev,
134 				    struct hwmon_device *hwdev, int index)
135 {
136 	struct hwmon_thermal_data *tdata;
137 
138 	tdata = devm_kzalloc(dev, sizeof(*tdata), GFP_KERNEL);
139 	if (!tdata)
140 		return -ENOMEM;
141 
142 	tdata->hwdev = hwdev;
143 	tdata->index = index;
144 
145 	devm_thermal_zone_of_sensor_register(&hwdev->dev, index, tdata,
146 					     &hwmon_thermal_ops);
147 
148 	return 0;
149 }
150 #else
151 static int hwmon_thermal_add_sensor(struct device *dev,
152 				    struct hwmon_device *hwdev, int index)
153 {
154 	return 0;
155 }
156 #endif /* IS_REACHABLE(CONFIG_THERMAL) && defined(CONFIG_THERMAL_OF) */
157 
158 /* sysfs attribute management */
159 
160 static ssize_t hwmon_attr_show(struct device *dev,
161 			       struct device_attribute *devattr, char *buf)
162 {
163 	struct hwmon_device_attribute *hattr = to_hwmon_attr(devattr);
164 	long val;
165 	int ret;
166 
167 	ret = hattr->ops->read(dev, hattr->type, hattr->attr, hattr->index,
168 			       &val);
169 	if (ret < 0)
170 		return ret;
171 
172 	return sprintf(buf, "%ld\n", val);
173 }
174 
175 static ssize_t hwmon_attr_store(struct device *dev,
176 				struct device_attribute *devattr,
177 				const char *buf, size_t count)
178 {
179 	struct hwmon_device_attribute *hattr = to_hwmon_attr(devattr);
180 	long val;
181 	int ret;
182 
183 	ret = kstrtol(buf, 10, &val);
184 	if (ret < 0)
185 		return ret;
186 
187 	ret = hattr->ops->write(dev, hattr->type, hattr->attr, hattr->index,
188 				val);
189 	if (ret < 0)
190 		return ret;
191 
192 	return count;
193 }
194 
195 static int hwmon_attr_base(enum hwmon_sensor_types type)
196 {
197 	if (type == hwmon_in)
198 		return 0;
199 	return 1;
200 }
201 
202 static struct attribute *hwmon_genattr(struct device *dev,
203 				       const void *drvdata,
204 				       enum hwmon_sensor_types type,
205 				       u32 attr,
206 				       int index,
207 				       const char *template,
208 				       const struct hwmon_ops *ops)
209 {
210 	struct hwmon_device_attribute *hattr;
211 	struct device_attribute *dattr;
212 	struct attribute *a;
213 	umode_t mode;
214 	char *name;
215 
216 	/* The attribute is invisible if there is no template string */
217 	if (!template)
218 		return ERR_PTR(-ENOENT);
219 
220 	mode = ops->is_visible(drvdata, type, attr, index);
221 	if (!mode)
222 		return ERR_PTR(-ENOENT);
223 
224 	if ((mode & S_IRUGO) && !ops->read)
225 		return ERR_PTR(-EINVAL);
226 	if ((mode & S_IWUGO) && !ops->write)
227 		return ERR_PTR(-EINVAL);
228 
229 	if (type == hwmon_chip) {
230 		name = (char *)template;
231 	} else {
232 		name = devm_kzalloc(dev, strlen(template) + 16, GFP_KERNEL);
233 		if (!name)
234 			return ERR_PTR(-ENOMEM);
235 		scnprintf(name, strlen(template) + 16, template,
236 			  index + hwmon_attr_base(type));
237 	}
238 
239 	hattr = devm_kzalloc(dev, sizeof(*hattr), GFP_KERNEL);
240 	if (!hattr)
241 		return ERR_PTR(-ENOMEM);
242 
243 	hattr->type = type;
244 	hattr->attr = attr;
245 	hattr->index = index;
246 	hattr->ops = ops;
247 
248 	dattr = &hattr->dev_attr;
249 	dattr->show = hwmon_attr_show;
250 	dattr->store = hwmon_attr_store;
251 
252 	a = &dattr->attr;
253 	sysfs_attr_init(a);
254 	a->name = name;
255 	a->mode = mode;
256 
257 	return a;
258 }
259 
260 static const char * const hwmon_chip_attr_templates[] = {
261 	[hwmon_chip_temp_reset_history] = "temp_reset_history",
262 	[hwmon_chip_in_reset_history] = "in_reset_history",
263 	[hwmon_chip_curr_reset_history] = "curr_reset_history",
264 	[hwmon_chip_update_interval] = "update_interval",
265 	[hwmon_chip_alarms] = "alarms",
266 };
267 
268 static const char * const hwmon_temp_attr_templates[] = {
269 	[hwmon_temp_input] = "temp%d_input",
270 	[hwmon_temp_type] = "temp%d_type",
271 	[hwmon_temp_lcrit] = "temp%d_lcrit",
272 	[hwmon_temp_lcrit_hyst] = "temp%d_lcrit_hyst",
273 	[hwmon_temp_min] = "temp%d_min",
274 	[hwmon_temp_min_hyst] = "temp%d_min_hyst",
275 	[hwmon_temp_max] = "temp%d_max",
276 	[hwmon_temp_max_hyst] = "temp%d_max_hyst",
277 	[hwmon_temp_crit] = "temp%d_crit",
278 	[hwmon_temp_crit_hyst] = "temp%d_crit_hyst",
279 	[hwmon_temp_emergency] = "temp%d_emergency",
280 	[hwmon_temp_emergency_hyst] = "temp%d_emergency_hyst",
281 	[hwmon_temp_alarm] = "temp%d_alarm",
282 	[hwmon_temp_lcrit_alarm] = "temp%d_lcrit_alarm",
283 	[hwmon_temp_min_alarm] = "temp%d_min_alarm",
284 	[hwmon_temp_max_alarm] = "temp%d_max_alarm",
285 	[hwmon_temp_crit_alarm] = "temp%d_crit_alarm",
286 	[hwmon_temp_emergency_alarm] = "temp%d_emergency_alarm",
287 	[hwmon_temp_fault] = "temp%d_fault",
288 	[hwmon_temp_offset] = "temp%d_offset",
289 	[hwmon_temp_label] = "temp%d_label",
290 	[hwmon_temp_lowest] = "temp%d_lowest",
291 	[hwmon_temp_highest] = "temp%d_highest",
292 	[hwmon_temp_reset_history] = "temp%d_reset_history",
293 };
294 
295 static const char * const hwmon_in_attr_templates[] = {
296 	[hwmon_in_input] = "in%d_input",
297 	[hwmon_in_min] = "in%d_min",
298 	[hwmon_in_max] = "in%d_max",
299 	[hwmon_in_lcrit] = "in%d_lcrit",
300 	[hwmon_in_crit] = "in%d_crit",
301 	[hwmon_in_average] = "in%d_average",
302 	[hwmon_in_lowest] = "in%d_lowest",
303 	[hwmon_in_highest] = "in%d_highest",
304 	[hwmon_in_reset_history] = "in%d_reset_history",
305 	[hwmon_in_label] = "in%d_label",
306 	[hwmon_in_alarm] = "in%d_alarm",
307 	[hwmon_in_min_alarm] = "in%d_min_alarm",
308 	[hwmon_in_max_alarm] = "in%d_max_alarm",
309 	[hwmon_in_lcrit_alarm] = "in%d_lcrit_alarm",
310 	[hwmon_in_crit_alarm] = "in%d_crit_alarm",
311 };
312 
313 static const char * const hwmon_curr_attr_templates[] = {
314 	[hwmon_curr_input] = "curr%d_input",
315 	[hwmon_curr_min] = "curr%d_min",
316 	[hwmon_curr_max] = "curr%d_max",
317 	[hwmon_curr_lcrit] = "curr%d_lcrit",
318 	[hwmon_curr_crit] = "curr%d_crit",
319 	[hwmon_curr_average] = "curr%d_average",
320 	[hwmon_curr_lowest] = "curr%d_lowest",
321 	[hwmon_curr_highest] = "curr%d_highest",
322 	[hwmon_curr_reset_history] = "curr%d_reset_history",
323 	[hwmon_curr_label] = "curr%d_label",
324 	[hwmon_curr_alarm] = "curr%d_alarm",
325 	[hwmon_curr_min_alarm] = "curr%d_min_alarm",
326 	[hwmon_curr_max_alarm] = "curr%d_max_alarm",
327 	[hwmon_curr_lcrit_alarm] = "curr%d_lcrit_alarm",
328 	[hwmon_curr_crit_alarm] = "curr%d_crit_alarm",
329 };
330 
331 static const char * const *__templates[] = {
332 	[hwmon_chip] = hwmon_chip_attr_templates,
333 	[hwmon_temp] = hwmon_temp_attr_templates,
334 	[hwmon_in] = hwmon_in_attr_templates,
335 	[hwmon_curr] = hwmon_curr_attr_templates,
336 };
337 
338 static const int __templates_size[] = {
339 	[hwmon_chip] = ARRAY_SIZE(hwmon_chip_attr_templates),
340 	[hwmon_temp] = ARRAY_SIZE(hwmon_temp_attr_templates),
341 	[hwmon_in] = ARRAY_SIZE(hwmon_in_attr_templates),
342 	[hwmon_curr] = ARRAY_SIZE(hwmon_curr_attr_templates),
343 };
344 
345 static int hwmon_num_channel_attrs(const struct hwmon_channel_info *info)
346 {
347 	int i, n;
348 
349 	for (i = n = 0; info->config[i]; i++)
350 		n += hweight32(info->config[i]);
351 
352 	return n;
353 }
354 
355 static int hwmon_genattrs(struct device *dev,
356 			  const void *drvdata,
357 			  struct attribute **attrs,
358 			  const struct hwmon_ops *ops,
359 			  const struct hwmon_channel_info *info)
360 {
361 	const char * const *templates;
362 	int template_size;
363 	int i, aindex = 0;
364 
365 	if (info->type >= ARRAY_SIZE(__templates))
366 		return -EINVAL;
367 
368 	templates = __templates[info->type];
369 	template_size = __templates_size[info->type];
370 
371 	for (i = 0; info->config[i]; i++) {
372 		u32 attr_mask = info->config[i];
373 		u32 attr;
374 
375 		while (attr_mask) {
376 			struct attribute *a;
377 
378 			attr = __ffs(attr_mask);
379 			attr_mask &= ~BIT(attr);
380 			if (attr >= template_size)
381 				return -EINVAL;
382 			a = hwmon_genattr(dev, drvdata, info->type, attr, i,
383 					  templates[attr], ops);
384 			if (IS_ERR(a)) {
385 				if (PTR_ERR(a) != -ENOENT)
386 					return PTR_ERR(a);
387 				continue;
388 			}
389 			attrs[aindex++] = a;
390 		}
391 	}
392 	return aindex;
393 }
394 
395 static struct attribute **
396 __hwmon_create_attrs(struct device *dev, const void *drvdata,
397 		     const struct hwmon_chip_info *chip)
398 {
399 	int ret, i, aindex = 0, nattrs = 0;
400 	struct attribute **attrs;
401 
402 	for (i = 0; chip->info[i]; i++)
403 		nattrs += hwmon_num_channel_attrs(chip->info[i]);
404 
405 	if (nattrs == 0)
406 		return ERR_PTR(-EINVAL);
407 
408 	attrs = devm_kcalloc(dev, nattrs + 1, sizeof(*attrs), GFP_KERNEL);
409 	if (!attrs)
410 		return ERR_PTR(-ENOMEM);
411 
412 	for (i = 0; chip->info[i]; i++) {
413 		ret = hwmon_genattrs(dev, drvdata, &attrs[aindex], chip->ops,
414 				     chip->info[i]);
415 		if (ret < 0)
416 			return ERR_PTR(ret);
417 		aindex += ret;
418 	}
419 
420 	return attrs;
421 }
422 
423 static struct device *
424 __hwmon_device_register(struct device *dev, const char *name, void *drvdata,
425 			const struct hwmon_chip_info *chip,
426 			const struct attribute_group **groups)
427 {
428 	struct hwmon_device *hwdev;
429 	struct device *hdev;
430 	int i, j, err, id;
431 
432 	/* Do not accept invalid characters in hwmon name attribute */
433 	if (name && (!strlen(name) || strpbrk(name, "-* \t\n")))
434 		return ERR_PTR(-EINVAL);
435 
436 	id = ida_simple_get(&hwmon_ida, 0, 0, GFP_KERNEL);
437 	if (id < 0)
438 		return ERR_PTR(id);
439 
440 	hwdev = kzalloc(sizeof(*hwdev), GFP_KERNEL);
441 	if (hwdev == NULL) {
442 		err = -ENOMEM;
443 		goto ida_remove;
444 	}
445 
446 	hdev = &hwdev->dev;
447 
448 	if (chip && chip->ops->is_visible) {
449 		struct attribute **attrs;
450 		int ngroups = 2;
451 
452 		if (groups)
453 			for (i = 0; groups[i]; i++)
454 				ngroups++;
455 
456 		hwdev->groups = devm_kcalloc(dev, ngroups, sizeof(*groups),
457 					     GFP_KERNEL);
458 		if (!hwdev->groups)
459 			return ERR_PTR(-ENOMEM);
460 
461 		attrs = __hwmon_create_attrs(dev, drvdata, chip);
462 		if (IS_ERR(attrs)) {
463 			err = PTR_ERR(attrs);
464 			goto free_hwmon;
465 		}
466 
467 		hwdev->group.attrs = attrs;
468 		ngroups = 0;
469 		hwdev->groups[ngroups++] = &hwdev->group;
470 
471 		if (groups) {
472 			for (i = 0; groups[i]; i++)
473 				hwdev->groups[ngroups++] = groups[i];
474 		}
475 
476 		hdev->groups = hwdev->groups;
477 	} else {
478 		hdev->groups = groups;
479 	}
480 
481 	hwdev->name = name;
482 	hdev->class = &hwmon_class;
483 	hdev->parent = dev;
484 	hdev->of_node = dev ? dev->of_node : NULL;
485 	hwdev->chip = chip;
486 	dev_set_drvdata(hdev, drvdata);
487 	dev_set_name(hdev, HWMON_ID_FORMAT, id);
488 	err = device_register(hdev);
489 	if (err)
490 		goto free_hwmon;
491 
492 	if (chip && chip->ops->is_visible && chip->ops->read &&
493 	    chip->info[0]->type == hwmon_chip &&
494 	    (chip->info[0]->config[0] & HWMON_C_REGISTER_TZ)) {
495 		const struct hwmon_channel_info **info = chip->info;
496 
497 		for (i = 1; info[i]; i++) {
498 			if (info[i]->type != hwmon_temp)
499 				continue;
500 
501 			for (j = 0; info[i]->config[j]; j++) {
502 				if (!chip->ops->is_visible(drvdata, hwmon_temp,
503 							   hwmon_temp_input, j))
504 					continue;
505 				if (info[i]->config[j] & HWMON_T_INPUT)
506 					hwmon_thermal_add_sensor(dev, hwdev, j);
507 			}
508 		}
509 	}
510 
511 	return hdev;
512 
513 free_hwmon:
514 	kfree(hwdev);
515 ida_remove:
516 	ida_simple_remove(&hwmon_ida, id);
517 	return ERR_PTR(err);
518 }
519 
520 /**
521  * hwmon_device_register_with_groups - register w/ hwmon
522  * @dev: the parent device
523  * @name: hwmon name attribute
524  * @drvdata: driver data to attach to created device
525  * @groups: List of attribute groups to create
526  *
527  * hwmon_device_unregister() must be called when the device is no
528  * longer needed.
529  *
530  * Returns the pointer to the new device.
531  */
532 struct device *
533 hwmon_device_register_with_groups(struct device *dev, const char *name,
534 				  void *drvdata,
535 				  const struct attribute_group **groups)
536 {
537 	return __hwmon_device_register(dev, name, drvdata, NULL, groups);
538 }
539 EXPORT_SYMBOL_GPL(hwmon_device_register_with_groups);
540 
541 /**
542  * hwmon_device_register_with_info - register w/ hwmon
543  * @dev: the parent device
544  * @name: hwmon name attribute
545  * @drvdata: driver data to attach to created device
546  * @info: Pointer to hwmon chip information
547  * @groups - pointer to list of driver specific attribute groups
548  *
549  * hwmon_device_unregister() must be called when the device is no
550  * longer needed.
551  *
552  * Returns the pointer to the new device.
553  */
554 struct device *
555 hwmon_device_register_with_info(struct device *dev, const char *name,
556 				void *drvdata,
557 				const struct hwmon_chip_info *chip,
558 				const struct attribute_group **groups)
559 {
560 	if (chip && (!chip->ops || !chip->info))
561 		return ERR_PTR(-EINVAL);
562 
563 	return __hwmon_device_register(dev, name, drvdata, chip, groups);
564 }
565 EXPORT_SYMBOL_GPL(hwmon_device_register_with_info);
566 
567 /**
568  * hwmon_device_register - register w/ hwmon
569  * @dev: the device to register
570  *
571  * hwmon_device_unregister() must be called when the device is no
572  * longer needed.
573  *
574  * Returns the pointer to the new device.
575  */
576 struct device *hwmon_device_register(struct device *dev)
577 {
578 	return hwmon_device_register_with_groups(dev, NULL, NULL, NULL);
579 }
580 EXPORT_SYMBOL_GPL(hwmon_device_register);
581 
582 /**
583  * hwmon_device_unregister - removes the previously registered class device
584  *
585  * @dev: the class device to destroy
586  */
587 void hwmon_device_unregister(struct device *dev)
588 {
589 	int id;
590 
591 	if (likely(sscanf(dev_name(dev), HWMON_ID_FORMAT, &id) == 1)) {
592 		device_unregister(dev);
593 		ida_simple_remove(&hwmon_ida, id);
594 	} else
595 		dev_dbg(dev->parent,
596 			"hwmon_device_unregister() failed: bad class ID!\n");
597 }
598 EXPORT_SYMBOL_GPL(hwmon_device_unregister);
599 
600 static void devm_hwmon_release(struct device *dev, void *res)
601 {
602 	struct device *hwdev = *(struct device **)res;
603 
604 	hwmon_device_unregister(hwdev);
605 }
606 
607 /**
608  * devm_hwmon_device_register_with_groups - register w/ hwmon
609  * @dev: the parent device
610  * @name: hwmon name attribute
611  * @drvdata: driver data to attach to created device
612  * @groups: List of attribute groups to create
613  *
614  * Returns the pointer to the new device. The new device is automatically
615  * unregistered with the parent device.
616  */
617 struct device *
618 devm_hwmon_device_register_with_groups(struct device *dev, const char *name,
619 				       void *drvdata,
620 				       const struct attribute_group **groups)
621 {
622 	struct device **ptr, *hwdev;
623 
624 	if (!dev)
625 		return ERR_PTR(-EINVAL);
626 
627 	ptr = devres_alloc(devm_hwmon_release, sizeof(*ptr), GFP_KERNEL);
628 	if (!ptr)
629 		return ERR_PTR(-ENOMEM);
630 
631 	hwdev = hwmon_device_register_with_groups(dev, name, drvdata, groups);
632 	if (IS_ERR(hwdev))
633 		goto error;
634 
635 	*ptr = hwdev;
636 	devres_add(dev, ptr);
637 	return hwdev;
638 
639 error:
640 	devres_free(ptr);
641 	return hwdev;
642 }
643 EXPORT_SYMBOL_GPL(devm_hwmon_device_register_with_groups);
644 
645 /**
646  * devm_hwmon_device_register_with_info - register w/ hwmon
647  * @dev: the parent device
648  * @name: hwmon name attribute
649  * @drvdata: driver data to attach to created device
650  * @info: Pointer to hwmon chip information
651  * @groups - pointer to list of driver specific attribute groups
652  *
653  * Returns the pointer to the new device. The new device is automatically
654  * unregistered with the parent device.
655  */
656 struct device *
657 devm_hwmon_device_register_with_info(struct device *dev, const char *name,
658 				     void *drvdata,
659 				     const struct hwmon_chip_info *chip,
660 				     const struct attribute_group **groups)
661 {
662 	struct device **ptr, *hwdev;
663 
664 	if (!dev)
665 		return ERR_PTR(-EINVAL);
666 
667 	ptr = devres_alloc(devm_hwmon_release, sizeof(*ptr), GFP_KERNEL);
668 	if (!ptr)
669 		return ERR_PTR(-ENOMEM);
670 
671 	hwdev = hwmon_device_register_with_info(dev, name, drvdata, chip,
672 						groups);
673 	if (IS_ERR(hwdev))
674 		goto error;
675 
676 	*ptr = hwdev;
677 	devres_add(dev, ptr);
678 
679 	return hwdev;
680 
681 error:
682 	devres_free(ptr);
683 	return hwdev;
684 }
685 EXPORT_SYMBOL_GPL(devm_hwmon_device_register_with_info);
686 
687 static int devm_hwmon_match(struct device *dev, void *res, void *data)
688 {
689 	struct device **hwdev = res;
690 
691 	return *hwdev == data;
692 }
693 
694 /**
695  * devm_hwmon_device_unregister - removes a previously registered hwmon device
696  *
697  * @dev: the parent device of the device to unregister
698  */
699 void devm_hwmon_device_unregister(struct device *dev)
700 {
701 	WARN_ON(devres_release(dev, devm_hwmon_release, devm_hwmon_match, dev));
702 }
703 EXPORT_SYMBOL_GPL(devm_hwmon_device_unregister);
704 
705 static void __init hwmon_pci_quirks(void)
706 {
707 #if defined CONFIG_X86 && defined CONFIG_PCI
708 	struct pci_dev *sb;
709 	u16 base;
710 	u8 enable;
711 
712 	/* Open access to 0x295-0x296 on MSI MS-7031 */
713 	sb = pci_get_device(PCI_VENDOR_ID_ATI, 0x436c, NULL);
714 	if (sb) {
715 		if (sb->subsystem_vendor == 0x1462 &&	/* MSI */
716 		    sb->subsystem_device == 0x0031) {	/* MS-7031 */
717 			pci_read_config_byte(sb, 0x48, &enable);
718 			pci_read_config_word(sb, 0x64, &base);
719 
720 			if (base == 0 && !(enable & BIT(2))) {
721 				dev_info(&sb->dev,
722 					 "Opening wide generic port at 0x295\n");
723 				pci_write_config_word(sb, 0x64, 0x295);
724 				pci_write_config_byte(sb, 0x48,
725 						      enable | BIT(2));
726 			}
727 		}
728 		pci_dev_put(sb);
729 	}
730 #endif
731 }
732 
733 static int __init hwmon_init(void)
734 {
735 	int err;
736 
737 	hwmon_pci_quirks();
738 
739 	err = class_register(&hwmon_class);
740 	if (err) {
741 		pr_err("couldn't register hwmon sysfs class\n");
742 		return err;
743 	}
744 	return 0;
745 }
746 
747 static void __exit hwmon_exit(void)
748 {
749 	class_unregister(&hwmon_class);
750 }
751 
752 subsys_initcall(hwmon_init);
753 module_exit(hwmon_exit);
754 
755 MODULE_AUTHOR("Mark M. Hoffman <mhoffman@lightlink.com>");
756 MODULE_DESCRIPTION("hardware monitoring sysfs/class support");
757 MODULE_LICENSE("GPL");
758 
759