1 /*
2  * A hwmon driver for ACPI 4.0 power meters
3  * Copyright (C) 2009 IBM
4  *
5  * Author: Darrick J. Wong <darrick.wong@oracle.com>
6  *
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.
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 <linux/module.h>
23 #include <linux/hwmon.h>
24 #include <linux/hwmon-sysfs.h>
25 #include <linux/jiffies.h>
26 #include <linux/mutex.h>
27 #include <linux/dmi.h>
28 #include <linux/slab.h>
29 #include <linux/kdev_t.h>
30 #include <linux/sched.h>
31 #include <linux/time.h>
32 #include <linux/err.h>
33 #include <linux/acpi.h>
34 
35 #define ACPI_POWER_METER_NAME		"power_meter"
36 ACPI_MODULE_NAME(ACPI_POWER_METER_NAME);
37 #define ACPI_POWER_METER_DEVICE_NAME	"Power Meter"
38 #define ACPI_POWER_METER_CLASS		"pwr_meter_resource"
39 
40 #define NUM_SENSORS			17
41 
42 #define POWER_METER_CAN_MEASURE	(1 << 0)
43 #define POWER_METER_CAN_TRIP	(1 << 1)
44 #define POWER_METER_CAN_CAP	(1 << 2)
45 #define POWER_METER_CAN_NOTIFY	(1 << 3)
46 #define POWER_METER_IS_BATTERY	(1 << 8)
47 #define UNKNOWN_HYSTERESIS	0xFFFFFFFF
48 
49 #define METER_NOTIFY_CONFIG	0x80
50 #define METER_NOTIFY_TRIP	0x81
51 #define METER_NOTIFY_CAP	0x82
52 #define METER_NOTIFY_CAPPING	0x83
53 #define METER_NOTIFY_INTERVAL	0x84
54 
55 #define POWER_AVERAGE_NAME	"power1_average"
56 #define POWER_CAP_NAME		"power1_cap"
57 #define POWER_AVG_INTERVAL_NAME	"power1_average_interval"
58 #define POWER_ALARM_NAME	"power1_alarm"
59 
60 static int cap_in_hardware;
61 static bool force_cap_on;
62 
63 static int can_cap_in_hardware(void)
64 {
65 	return force_cap_on || cap_in_hardware;
66 }
67 
68 static const struct acpi_device_id power_meter_ids[] = {
69 	{"ACPI000D", 0},
70 	{"", 0},
71 };
72 MODULE_DEVICE_TABLE(acpi, power_meter_ids);
73 
74 struct acpi_power_meter_capabilities {
75 	u64		flags;
76 	u64		units;
77 	u64		type;
78 	u64		accuracy;
79 	u64		sampling_time;
80 	u64		min_avg_interval;
81 	u64		max_avg_interval;
82 	u64		hysteresis;
83 	u64		configurable_cap;
84 	u64		min_cap;
85 	u64		max_cap;
86 };
87 
88 struct acpi_power_meter_resource {
89 	struct acpi_device	*acpi_dev;
90 	acpi_bus_id		name;
91 	struct mutex		lock;
92 	struct device		*hwmon_dev;
93 	struct acpi_power_meter_capabilities	caps;
94 	acpi_string		model_number;
95 	acpi_string		serial_number;
96 	acpi_string		oem_info;
97 	u64		power;
98 	u64		cap;
99 	u64		avg_interval;
100 	int			sensors_valid;
101 	unsigned long		sensors_last_updated;
102 	struct sensor_device_attribute	sensors[NUM_SENSORS];
103 	int			num_sensors;
104 	s64			trip[2];
105 	int			num_domain_devices;
106 	struct acpi_device	**domain_devices;
107 	struct kobject		*holders_dir;
108 };
109 
110 struct sensor_template {
111 	char *label;
112 	ssize_t (*show)(struct device *dev,
113 			struct device_attribute *devattr,
114 			char *buf);
115 	ssize_t (*set)(struct device *dev,
116 		       struct device_attribute *devattr,
117 		       const char *buf, size_t count);
118 	int index;
119 };
120 
121 /* Averaging interval */
122 static int update_avg_interval(struct acpi_power_meter_resource *resource)
123 {
124 	unsigned long long data;
125 	acpi_status status;
126 
127 	status = acpi_evaluate_integer(resource->acpi_dev->handle, "_GAI",
128 				       NULL, &data);
129 	if (ACPI_FAILURE(status)) {
130 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _GAI"));
131 		return -ENODEV;
132 	}
133 
134 	resource->avg_interval = data;
135 	return 0;
136 }
137 
138 static ssize_t show_avg_interval(struct device *dev,
139 				 struct device_attribute *devattr,
140 				 char *buf)
141 {
142 	struct acpi_device *acpi_dev = to_acpi_device(dev);
143 	struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
144 
145 	mutex_lock(&resource->lock);
146 	update_avg_interval(resource);
147 	mutex_unlock(&resource->lock);
148 
149 	return sprintf(buf, "%llu\n", resource->avg_interval);
150 }
151 
152 static ssize_t set_avg_interval(struct device *dev,
153 				struct device_attribute *devattr,
154 				const char *buf, size_t count)
155 {
156 	struct acpi_device *acpi_dev = to_acpi_device(dev);
157 	struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
158 	union acpi_object arg0 = { ACPI_TYPE_INTEGER };
159 	struct acpi_object_list args = { 1, &arg0 };
160 	int res;
161 	unsigned long temp;
162 	unsigned long long data;
163 	acpi_status status;
164 
165 	res = kstrtoul(buf, 10, &temp);
166 	if (res)
167 		return res;
168 
169 	if (temp > resource->caps.max_avg_interval ||
170 	    temp < resource->caps.min_avg_interval)
171 		return -EINVAL;
172 	arg0.integer.value = temp;
173 
174 	mutex_lock(&resource->lock);
175 	status = acpi_evaluate_integer(resource->acpi_dev->handle, "_PAI",
176 				       &args, &data);
177 	if (!ACPI_FAILURE(status))
178 		resource->avg_interval = temp;
179 	mutex_unlock(&resource->lock);
180 
181 	if (ACPI_FAILURE(status)) {
182 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PAI"));
183 		return -EINVAL;
184 	}
185 
186 	/* _PAI returns 0 on success, nonzero otherwise */
187 	if (data)
188 		return -EINVAL;
189 
190 	return count;
191 }
192 
193 /* Cap functions */
194 static int update_cap(struct acpi_power_meter_resource *resource)
195 {
196 	unsigned long long data;
197 	acpi_status status;
198 
199 	status = acpi_evaluate_integer(resource->acpi_dev->handle, "_GHL",
200 				       NULL, &data);
201 	if (ACPI_FAILURE(status)) {
202 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _GHL"));
203 		return -ENODEV;
204 	}
205 
206 	resource->cap = data;
207 	return 0;
208 }
209 
210 static ssize_t show_cap(struct device *dev,
211 			struct device_attribute *devattr,
212 			char *buf)
213 {
214 	struct acpi_device *acpi_dev = to_acpi_device(dev);
215 	struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
216 
217 	mutex_lock(&resource->lock);
218 	update_cap(resource);
219 	mutex_unlock(&resource->lock);
220 
221 	return sprintf(buf, "%llu\n", resource->cap * 1000);
222 }
223 
224 static ssize_t set_cap(struct device *dev, struct device_attribute *devattr,
225 		       const char *buf, size_t count)
226 {
227 	struct acpi_device *acpi_dev = to_acpi_device(dev);
228 	struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
229 	union acpi_object arg0 = { ACPI_TYPE_INTEGER };
230 	struct acpi_object_list args = { 1, &arg0 };
231 	int res;
232 	unsigned long temp;
233 	unsigned long long data;
234 	acpi_status status;
235 
236 	res = kstrtoul(buf, 10, &temp);
237 	if (res)
238 		return res;
239 
240 	temp = DIV_ROUND_CLOSEST(temp, 1000);
241 	if (temp > resource->caps.max_cap || temp < resource->caps.min_cap)
242 		return -EINVAL;
243 	arg0.integer.value = temp;
244 
245 	mutex_lock(&resource->lock);
246 	status = acpi_evaluate_integer(resource->acpi_dev->handle, "_SHL",
247 				       &args, &data);
248 	if (!ACPI_FAILURE(status))
249 		resource->cap = temp;
250 	mutex_unlock(&resource->lock);
251 
252 	if (ACPI_FAILURE(status)) {
253 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _SHL"));
254 		return -EINVAL;
255 	}
256 
257 	/* _SHL returns 0 on success, nonzero otherwise */
258 	if (data)
259 		return -EINVAL;
260 
261 	return count;
262 }
263 
264 /* Power meter trip points */
265 static int set_acpi_trip(struct acpi_power_meter_resource *resource)
266 {
267 	union acpi_object arg_objs[] = {
268 		{ACPI_TYPE_INTEGER},
269 		{ACPI_TYPE_INTEGER}
270 	};
271 	struct acpi_object_list args = { 2, arg_objs };
272 	unsigned long long data;
273 	acpi_status status;
274 
275 	/* Both trip levels must be set */
276 	if (resource->trip[0] < 0 || resource->trip[1] < 0)
277 		return 0;
278 
279 	/* This driver stores min, max; ACPI wants max, min. */
280 	arg_objs[0].integer.value = resource->trip[1];
281 	arg_objs[1].integer.value = resource->trip[0];
282 
283 	status = acpi_evaluate_integer(resource->acpi_dev->handle, "_PTP",
284 				       &args, &data);
285 	if (ACPI_FAILURE(status)) {
286 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PTP"));
287 		return -EINVAL;
288 	}
289 
290 	/* _PTP returns 0 on success, nonzero otherwise */
291 	if (data)
292 		return -EINVAL;
293 
294 	return 0;
295 }
296 
297 static ssize_t set_trip(struct device *dev, struct device_attribute *devattr,
298 			const char *buf, size_t count)
299 {
300 	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
301 	struct acpi_device *acpi_dev = to_acpi_device(dev);
302 	struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
303 	int res;
304 	unsigned long temp;
305 
306 	res = kstrtoul(buf, 10, &temp);
307 	if (res)
308 		return res;
309 
310 	temp = DIV_ROUND_CLOSEST(temp, 1000);
311 
312 	mutex_lock(&resource->lock);
313 	resource->trip[attr->index - 7] = temp;
314 	res = set_acpi_trip(resource);
315 	mutex_unlock(&resource->lock);
316 
317 	if (res)
318 		return res;
319 
320 	return count;
321 }
322 
323 /* Power meter */
324 static int update_meter(struct acpi_power_meter_resource *resource)
325 {
326 	unsigned long long data;
327 	acpi_status status;
328 	unsigned long local_jiffies = jiffies;
329 
330 	if (time_before(local_jiffies, resource->sensors_last_updated +
331 			msecs_to_jiffies(resource->caps.sampling_time)) &&
332 			resource->sensors_valid)
333 		return 0;
334 
335 	status = acpi_evaluate_integer(resource->acpi_dev->handle, "_PMM",
336 				       NULL, &data);
337 	if (ACPI_FAILURE(status)) {
338 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PMM"));
339 		return -ENODEV;
340 	}
341 
342 	resource->power = data;
343 	resource->sensors_valid = 1;
344 	resource->sensors_last_updated = jiffies;
345 	return 0;
346 }
347 
348 static ssize_t show_power(struct device *dev,
349 			  struct device_attribute *devattr,
350 			  char *buf)
351 {
352 	struct acpi_device *acpi_dev = to_acpi_device(dev);
353 	struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
354 
355 	mutex_lock(&resource->lock);
356 	update_meter(resource);
357 	mutex_unlock(&resource->lock);
358 
359 	return sprintf(buf, "%llu\n", resource->power * 1000);
360 }
361 
362 /* Miscellaneous */
363 static ssize_t show_str(struct device *dev,
364 			struct device_attribute *devattr,
365 			char *buf)
366 {
367 	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
368 	struct acpi_device *acpi_dev = to_acpi_device(dev);
369 	struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
370 	acpi_string val;
371 
372 	switch (attr->index) {
373 	case 0:
374 		val = resource->model_number;
375 		break;
376 	case 1:
377 		val = resource->serial_number;
378 		break;
379 	case 2:
380 		val = resource->oem_info;
381 		break;
382 	default:
383 		WARN(1, "Implementation error: unexpected attribute index %d\n",
384 		     attr->index);
385 		val = "";
386 		break;
387 	}
388 
389 	return sprintf(buf, "%s\n", val);
390 }
391 
392 static ssize_t show_val(struct device *dev,
393 			struct device_attribute *devattr,
394 			char *buf)
395 {
396 	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
397 	struct acpi_device *acpi_dev = to_acpi_device(dev);
398 	struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
399 	u64 val = 0;
400 
401 	switch (attr->index) {
402 	case 0:
403 		val = resource->caps.min_avg_interval;
404 		break;
405 	case 1:
406 		val = resource->caps.max_avg_interval;
407 		break;
408 	case 2:
409 		val = resource->caps.min_cap * 1000;
410 		break;
411 	case 3:
412 		val = resource->caps.max_cap * 1000;
413 		break;
414 	case 4:
415 		if (resource->caps.hysteresis == UNKNOWN_HYSTERESIS)
416 			return sprintf(buf, "unknown\n");
417 
418 		val = resource->caps.hysteresis * 1000;
419 		break;
420 	case 5:
421 		if (resource->caps.flags & POWER_METER_IS_BATTERY)
422 			val = 1;
423 		else
424 			val = 0;
425 		break;
426 	case 6:
427 		if (resource->power > resource->cap)
428 			val = 1;
429 		else
430 			val = 0;
431 		break;
432 	case 7:
433 	case 8:
434 		if (resource->trip[attr->index - 7] < 0)
435 			return sprintf(buf, "unknown\n");
436 
437 		val = resource->trip[attr->index - 7] * 1000;
438 		break;
439 	default:
440 		WARN(1, "Implementation error: unexpected attribute index %d\n",
441 		     attr->index);
442 		break;
443 	}
444 
445 	return sprintf(buf, "%llu\n", val);
446 }
447 
448 static ssize_t show_accuracy(struct device *dev,
449 			     struct device_attribute *devattr,
450 			     char *buf)
451 {
452 	struct acpi_device *acpi_dev = to_acpi_device(dev);
453 	struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
454 	unsigned int acc = resource->caps.accuracy;
455 
456 	return sprintf(buf, "%u.%u%%\n", acc / 1000, acc % 1000);
457 }
458 
459 static ssize_t show_name(struct device *dev,
460 			 struct device_attribute *devattr,
461 			 char *buf)
462 {
463 	return sprintf(buf, "%s\n", ACPI_POWER_METER_NAME);
464 }
465 
466 #define RO_SENSOR_TEMPLATE(_label, _show, _index)	\
467 	{						\
468 		.label = _label,			\
469 		.show  = _show,				\
470 		.index = _index,			\
471 	}
472 
473 #define RW_SENSOR_TEMPLATE(_label, _show, _set, _index)	\
474 	{						\
475 		.label = _label,			\
476 		.show  = _show,				\
477 		.set   = _set,				\
478 		.index = _index,			\
479 	}
480 
481 /* Sensor descriptions.  If you add a sensor, update NUM_SENSORS above! */
482 static struct sensor_template meter_attrs[] = {
483 	RO_SENSOR_TEMPLATE(POWER_AVERAGE_NAME, show_power, 0),
484 	RO_SENSOR_TEMPLATE("power1_accuracy", show_accuracy, 0),
485 	RO_SENSOR_TEMPLATE("power1_average_interval_min", show_val, 0),
486 	RO_SENSOR_TEMPLATE("power1_average_interval_max", show_val, 1),
487 	RO_SENSOR_TEMPLATE("power1_is_battery", show_val, 5),
488 	RW_SENSOR_TEMPLATE(POWER_AVG_INTERVAL_NAME, show_avg_interval,
489 		set_avg_interval, 0),
490 	{},
491 };
492 
493 static struct sensor_template misc_cap_attrs[] = {
494 	RO_SENSOR_TEMPLATE("power1_cap_min", show_val, 2),
495 	RO_SENSOR_TEMPLATE("power1_cap_max", show_val, 3),
496 	RO_SENSOR_TEMPLATE("power1_cap_hyst", show_val, 4),
497 	RO_SENSOR_TEMPLATE(POWER_ALARM_NAME, show_val, 6),
498 	{},
499 };
500 
501 static struct sensor_template ro_cap_attrs[] = {
502 	RO_SENSOR_TEMPLATE(POWER_CAP_NAME, show_cap, 0),
503 	{},
504 };
505 
506 static struct sensor_template rw_cap_attrs[] = {
507 	RW_SENSOR_TEMPLATE(POWER_CAP_NAME, show_cap, set_cap, 0),
508 	{},
509 };
510 
511 static struct sensor_template trip_attrs[] = {
512 	RW_SENSOR_TEMPLATE("power1_average_min", show_val, set_trip, 7),
513 	RW_SENSOR_TEMPLATE("power1_average_max", show_val, set_trip, 8),
514 	{},
515 };
516 
517 static struct sensor_template misc_attrs[] = {
518 	RO_SENSOR_TEMPLATE("name", show_name, 0),
519 	RO_SENSOR_TEMPLATE("power1_model_number", show_str, 0),
520 	RO_SENSOR_TEMPLATE("power1_oem_info", show_str, 2),
521 	RO_SENSOR_TEMPLATE("power1_serial_number", show_str, 1),
522 	{},
523 };
524 
525 #undef RO_SENSOR_TEMPLATE
526 #undef RW_SENSOR_TEMPLATE
527 
528 /* Read power domain data */
529 static void remove_domain_devices(struct acpi_power_meter_resource *resource)
530 {
531 	int i;
532 
533 	if (!resource->num_domain_devices)
534 		return;
535 
536 	for (i = 0; i < resource->num_domain_devices; i++) {
537 		struct acpi_device *obj = resource->domain_devices[i];
538 		if (!obj)
539 			continue;
540 
541 		sysfs_remove_link(resource->holders_dir,
542 				  kobject_name(&obj->dev.kobj));
543 		put_device(&obj->dev);
544 	}
545 
546 	kfree(resource->domain_devices);
547 	kobject_put(resource->holders_dir);
548 	resource->num_domain_devices = 0;
549 }
550 
551 static int read_domain_devices(struct acpi_power_meter_resource *resource)
552 {
553 	int res = 0;
554 	int i;
555 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
556 	union acpi_object *pss;
557 	acpi_status status;
558 
559 	status = acpi_evaluate_object(resource->acpi_dev->handle, "_PMD", NULL,
560 				      &buffer);
561 	if (ACPI_FAILURE(status)) {
562 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PMD"));
563 		return -ENODEV;
564 	}
565 
566 	pss = buffer.pointer;
567 	if (!pss ||
568 	    pss->type != ACPI_TYPE_PACKAGE) {
569 		dev_err(&resource->acpi_dev->dev, ACPI_POWER_METER_NAME
570 			"Invalid _PMD data\n");
571 		res = -EFAULT;
572 		goto end;
573 	}
574 
575 	if (!pss->package.count)
576 		goto end;
577 
578 	resource->domain_devices = kzalloc(sizeof(struct acpi_device *) *
579 					   pss->package.count, GFP_KERNEL);
580 	if (!resource->domain_devices) {
581 		res = -ENOMEM;
582 		goto end;
583 	}
584 
585 	resource->holders_dir = kobject_create_and_add("measures",
586 					&resource->acpi_dev->dev.kobj);
587 	if (!resource->holders_dir) {
588 		res = -ENOMEM;
589 		goto exit_free;
590 	}
591 
592 	resource->num_domain_devices = pss->package.count;
593 
594 	for (i = 0; i < pss->package.count; i++) {
595 		struct acpi_device *obj;
596 		union acpi_object *element = &(pss->package.elements[i]);
597 
598 		/* Refuse non-references */
599 		if (element->type != ACPI_TYPE_LOCAL_REFERENCE)
600 			continue;
601 
602 		/* Create a symlink to domain objects */
603 		resource->domain_devices[i] = NULL;
604 		if (acpi_bus_get_device(element->reference.handle,
605 					&resource->domain_devices[i]))
606 			continue;
607 
608 		obj = resource->domain_devices[i];
609 		get_device(&obj->dev);
610 
611 		res = sysfs_create_link(resource->holders_dir, &obj->dev.kobj,
612 				      kobject_name(&obj->dev.kobj));
613 		if (res) {
614 			put_device(&obj->dev);
615 			resource->domain_devices[i] = NULL;
616 		}
617 	}
618 
619 	res = 0;
620 	goto end;
621 
622 exit_free:
623 	kfree(resource->domain_devices);
624 end:
625 	kfree(buffer.pointer);
626 	return res;
627 }
628 
629 /* Registration and deregistration */
630 static int register_attrs(struct acpi_power_meter_resource *resource,
631 			  struct sensor_template *attrs)
632 {
633 	struct device *dev = &resource->acpi_dev->dev;
634 	struct sensor_device_attribute *sensors =
635 		&resource->sensors[resource->num_sensors];
636 	int res = 0;
637 
638 	while (attrs->label) {
639 		sensors->dev_attr.attr.name = attrs->label;
640 		sensors->dev_attr.attr.mode = S_IRUGO;
641 		sensors->dev_attr.show = attrs->show;
642 		sensors->index = attrs->index;
643 
644 		if (attrs->set) {
645 			sensors->dev_attr.attr.mode |= S_IWUSR;
646 			sensors->dev_attr.store = attrs->set;
647 		}
648 
649 		sysfs_attr_init(&sensors->dev_attr.attr);
650 		res = device_create_file(dev, &sensors->dev_attr);
651 		if (res) {
652 			sensors->dev_attr.attr.name = NULL;
653 			goto error;
654 		}
655 		sensors++;
656 		resource->num_sensors++;
657 		attrs++;
658 	}
659 
660 error:
661 	return res;
662 }
663 
664 static void remove_attrs(struct acpi_power_meter_resource *resource)
665 {
666 	int i;
667 
668 	for (i = 0; i < resource->num_sensors; i++) {
669 		if (!resource->sensors[i].dev_attr.attr.name)
670 			continue;
671 		device_remove_file(&resource->acpi_dev->dev,
672 				   &resource->sensors[i].dev_attr);
673 	}
674 
675 	remove_domain_devices(resource);
676 
677 	resource->num_sensors = 0;
678 }
679 
680 static int setup_attrs(struct acpi_power_meter_resource *resource)
681 {
682 	int res = 0;
683 
684 	res = read_domain_devices(resource);
685 	if (res)
686 		return res;
687 
688 	if (resource->caps.flags & POWER_METER_CAN_MEASURE) {
689 		res = register_attrs(resource, meter_attrs);
690 		if (res)
691 			goto error;
692 	}
693 
694 	if (resource->caps.flags & POWER_METER_CAN_CAP) {
695 		if (!can_cap_in_hardware()) {
696 			dev_err(&resource->acpi_dev->dev,
697 				"Ignoring unsafe software power cap!\n");
698 			goto skip_unsafe_cap;
699 		}
700 
701 		if (resource->caps.configurable_cap)
702 			res = register_attrs(resource, rw_cap_attrs);
703 		else
704 			res = register_attrs(resource, ro_cap_attrs);
705 
706 		if (res)
707 			goto error;
708 
709 		res = register_attrs(resource, misc_cap_attrs);
710 		if (res)
711 			goto error;
712 	}
713 
714 skip_unsafe_cap:
715 	if (resource->caps.flags & POWER_METER_CAN_TRIP) {
716 		res = register_attrs(resource, trip_attrs);
717 		if (res)
718 			goto error;
719 	}
720 
721 	res = register_attrs(resource, misc_attrs);
722 	if (res)
723 		goto error;
724 
725 	return res;
726 error:
727 	remove_attrs(resource);
728 	return res;
729 }
730 
731 static void free_capabilities(struct acpi_power_meter_resource *resource)
732 {
733 	acpi_string *str;
734 	int i;
735 
736 	str = &resource->model_number;
737 	for (i = 0; i < 3; i++, str++)
738 		kfree(*str);
739 }
740 
741 static int read_capabilities(struct acpi_power_meter_resource *resource)
742 {
743 	int res = 0;
744 	int i;
745 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
746 	struct acpi_buffer state = { 0, NULL };
747 	struct acpi_buffer format = { sizeof("NNNNNNNNNNN"), "NNNNNNNNNNN" };
748 	union acpi_object *pss;
749 	acpi_string *str;
750 	acpi_status status;
751 
752 	status = acpi_evaluate_object(resource->acpi_dev->handle, "_PMC", NULL,
753 				      &buffer);
754 	if (ACPI_FAILURE(status)) {
755 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PMC"));
756 		return -ENODEV;
757 	}
758 
759 	pss = buffer.pointer;
760 	if (!pss ||
761 	    pss->type != ACPI_TYPE_PACKAGE ||
762 	    pss->package.count != 14) {
763 		dev_err(&resource->acpi_dev->dev, ACPI_POWER_METER_NAME
764 			"Invalid _PMC data\n");
765 		res = -EFAULT;
766 		goto end;
767 	}
768 
769 	/* Grab all the integer data at once */
770 	state.length = sizeof(struct acpi_power_meter_capabilities);
771 	state.pointer = &resource->caps;
772 
773 	status = acpi_extract_package(pss, &format, &state);
774 	if (ACPI_FAILURE(status)) {
775 		ACPI_EXCEPTION((AE_INFO, status, "Invalid data"));
776 		res = -EFAULT;
777 		goto end;
778 	}
779 
780 	if (resource->caps.units) {
781 		dev_err(&resource->acpi_dev->dev, ACPI_POWER_METER_NAME
782 			"Unknown units %llu.\n",
783 			resource->caps.units);
784 		res = -EINVAL;
785 		goto end;
786 	}
787 
788 	/* Grab the string data */
789 	str = &resource->model_number;
790 
791 	for (i = 11; i < 14; i++) {
792 		union acpi_object *element = &(pss->package.elements[i]);
793 
794 		if (element->type != ACPI_TYPE_STRING) {
795 			res = -EINVAL;
796 			goto error;
797 		}
798 
799 		*str = kzalloc(sizeof(u8) * (element->string.length + 1),
800 			       GFP_KERNEL);
801 		if (!*str) {
802 			res = -ENOMEM;
803 			goto error;
804 		}
805 
806 		strncpy(*str, element->string.pointer, element->string.length);
807 		str++;
808 	}
809 
810 	dev_info(&resource->acpi_dev->dev, "Found ACPI power meter.\n");
811 	goto end;
812 error:
813 	str = &resource->model_number;
814 	for (i = 0; i < 3; i++, str++)
815 		kfree(*str);
816 end:
817 	kfree(buffer.pointer);
818 	return res;
819 }
820 
821 /* Handle ACPI event notifications */
822 static void acpi_power_meter_notify(struct acpi_device *device, u32 event)
823 {
824 	struct acpi_power_meter_resource *resource;
825 	int res;
826 
827 	if (!device || !acpi_driver_data(device))
828 		return;
829 
830 	resource = acpi_driver_data(device);
831 
832 	mutex_lock(&resource->lock);
833 	switch (event) {
834 	case METER_NOTIFY_CONFIG:
835 		free_capabilities(resource);
836 		res = read_capabilities(resource);
837 		if (res)
838 			break;
839 
840 		remove_attrs(resource);
841 		setup_attrs(resource);
842 		break;
843 	case METER_NOTIFY_TRIP:
844 		sysfs_notify(&device->dev.kobj, NULL, POWER_AVERAGE_NAME);
845 		update_meter(resource);
846 		break;
847 	case METER_NOTIFY_CAP:
848 		sysfs_notify(&device->dev.kobj, NULL, POWER_CAP_NAME);
849 		update_cap(resource);
850 		break;
851 	case METER_NOTIFY_INTERVAL:
852 		sysfs_notify(&device->dev.kobj, NULL, POWER_AVG_INTERVAL_NAME);
853 		update_avg_interval(resource);
854 		break;
855 	case METER_NOTIFY_CAPPING:
856 		sysfs_notify(&device->dev.kobj, NULL, POWER_ALARM_NAME);
857 		dev_info(&device->dev, "Capping in progress.\n");
858 		break;
859 	default:
860 		WARN(1, "Unexpected event %d\n", event);
861 		break;
862 	}
863 	mutex_unlock(&resource->lock);
864 
865 	acpi_bus_generate_netlink_event(ACPI_POWER_METER_CLASS,
866 					dev_name(&device->dev), event, 0);
867 }
868 
869 static int acpi_power_meter_add(struct acpi_device *device)
870 {
871 	int res;
872 	struct acpi_power_meter_resource *resource;
873 
874 	if (!device)
875 		return -EINVAL;
876 
877 	resource = kzalloc(sizeof(struct acpi_power_meter_resource),
878 			   GFP_KERNEL);
879 	if (!resource)
880 		return -ENOMEM;
881 
882 	resource->sensors_valid = 0;
883 	resource->acpi_dev = device;
884 	mutex_init(&resource->lock);
885 	strcpy(acpi_device_name(device), ACPI_POWER_METER_DEVICE_NAME);
886 	strcpy(acpi_device_class(device), ACPI_POWER_METER_CLASS);
887 	device->driver_data = resource;
888 
889 	free_capabilities(resource);
890 	res = read_capabilities(resource);
891 	if (res)
892 		goto exit_free;
893 
894 	resource->trip[0] = resource->trip[1] = -1;
895 
896 	res = setup_attrs(resource);
897 	if (res)
898 		goto exit_free;
899 
900 	resource->hwmon_dev = hwmon_device_register(&device->dev);
901 	if (IS_ERR(resource->hwmon_dev)) {
902 		res = PTR_ERR(resource->hwmon_dev);
903 		goto exit_remove;
904 	}
905 
906 	res = 0;
907 	goto exit;
908 
909 exit_remove:
910 	remove_attrs(resource);
911 exit_free:
912 	kfree(resource);
913 exit:
914 	return res;
915 }
916 
917 static int acpi_power_meter_remove(struct acpi_device *device)
918 {
919 	struct acpi_power_meter_resource *resource;
920 
921 	if (!device || !acpi_driver_data(device))
922 		return -EINVAL;
923 
924 	resource = acpi_driver_data(device);
925 	hwmon_device_unregister(resource->hwmon_dev);
926 
927 	free_capabilities(resource);
928 	remove_attrs(resource);
929 
930 	kfree(resource);
931 	return 0;
932 }
933 
934 #ifdef CONFIG_PM_SLEEP
935 
936 static int acpi_power_meter_resume(struct device *dev)
937 {
938 	struct acpi_power_meter_resource *resource;
939 
940 	if (!dev)
941 		return -EINVAL;
942 
943 	resource = acpi_driver_data(to_acpi_device(dev));
944 	if (!resource)
945 		return -EINVAL;
946 
947 	free_capabilities(resource);
948 	read_capabilities(resource);
949 
950 	return 0;
951 }
952 
953 #endif /* CONFIG_PM_SLEEP */
954 
955 static SIMPLE_DEV_PM_OPS(acpi_power_meter_pm, NULL, acpi_power_meter_resume);
956 
957 static struct acpi_driver acpi_power_meter_driver = {
958 	.name = "power_meter",
959 	.class = ACPI_POWER_METER_CLASS,
960 	.ids = power_meter_ids,
961 	.ops = {
962 		.add = acpi_power_meter_add,
963 		.remove = acpi_power_meter_remove,
964 		.notify = acpi_power_meter_notify,
965 		},
966 	.drv.pm = &acpi_power_meter_pm,
967 };
968 
969 /* Module init/exit routines */
970 static int __init enable_cap_knobs(const struct dmi_system_id *d)
971 {
972 	cap_in_hardware = 1;
973 	return 0;
974 }
975 
976 static struct dmi_system_id __initdata pm_dmi_table[] = {
977 	{
978 		enable_cap_knobs, "IBM Active Energy Manager",
979 		{
980 			DMI_MATCH(DMI_SYS_VENDOR, "IBM")
981 		},
982 	},
983 	{}
984 };
985 
986 static int __init acpi_power_meter_init(void)
987 {
988 	int result;
989 
990 	if (acpi_disabled)
991 		return -ENODEV;
992 
993 	dmi_check_system(pm_dmi_table);
994 
995 	result = acpi_bus_register_driver(&acpi_power_meter_driver);
996 	if (result < 0)
997 		return result;
998 
999 	return 0;
1000 }
1001 
1002 static void __exit acpi_power_meter_exit(void)
1003 {
1004 	acpi_bus_unregister_driver(&acpi_power_meter_driver);
1005 }
1006 
1007 MODULE_AUTHOR("Darrick J. Wong <darrick.wong@oracle.com>");
1008 MODULE_DESCRIPTION("ACPI 4.0 power meter driver");
1009 MODULE_LICENSE("GPL");
1010 
1011 module_param(force_cap_on, bool, 0644);
1012 MODULE_PARM_DESC(force_cap_on, "Enable power cap even it is unsafe to do so.");
1013 
1014 module_init(acpi_power_meter_init);
1015 module_exit(acpi_power_meter_exit);
1016