1 /*
2  * A hwmon driver for ACPI 4.0 power meters
3  * Copyright (C) 2009 IBM
4  *
5  * Author: Darrick J. Wong <djwong@us.ibm.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 <acpi/acpi_drivers.h>
33 #include <acpi/acpi_bus.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 		BUG();
384 		val = "";
385 	}
386 
387 	return sprintf(buf, "%s\n", val);
388 }
389 
390 static ssize_t show_val(struct device *dev,
391 			struct device_attribute *devattr,
392 			char *buf)
393 {
394 	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
395 	struct acpi_device *acpi_dev = to_acpi_device(dev);
396 	struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
397 	u64 val = 0;
398 
399 	switch (attr->index) {
400 	case 0:
401 		val = resource->caps.min_avg_interval;
402 		break;
403 	case 1:
404 		val = resource->caps.max_avg_interval;
405 		break;
406 	case 2:
407 		val = resource->caps.min_cap * 1000;
408 		break;
409 	case 3:
410 		val = resource->caps.max_cap * 1000;
411 		break;
412 	case 4:
413 		if (resource->caps.hysteresis == UNKNOWN_HYSTERESIS)
414 			return sprintf(buf, "unknown\n");
415 
416 		val = resource->caps.hysteresis * 1000;
417 		break;
418 	case 5:
419 		if (resource->caps.flags & POWER_METER_IS_BATTERY)
420 			val = 1;
421 		else
422 			val = 0;
423 		break;
424 	case 6:
425 		if (resource->power > resource->cap)
426 			val = 1;
427 		else
428 			val = 0;
429 		break;
430 	case 7:
431 	case 8:
432 		if (resource->trip[attr->index - 7] < 0)
433 			return sprintf(buf, "unknown\n");
434 
435 		val = resource->trip[attr->index - 7] * 1000;
436 		break;
437 	default:
438 		BUG();
439 	}
440 
441 	return sprintf(buf, "%llu\n", val);
442 }
443 
444 static ssize_t show_accuracy(struct device *dev,
445 			     struct device_attribute *devattr,
446 			     char *buf)
447 {
448 	struct acpi_device *acpi_dev = to_acpi_device(dev);
449 	struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
450 	unsigned int acc = resource->caps.accuracy;
451 
452 	return sprintf(buf, "%u.%u%%\n", acc / 1000, acc % 1000);
453 }
454 
455 static ssize_t show_name(struct device *dev,
456 			 struct device_attribute *devattr,
457 			 char *buf)
458 {
459 	return sprintf(buf, "%s\n", ACPI_POWER_METER_NAME);
460 }
461 
462 #define RO_SENSOR_TEMPLATE(_label, _show, _index)	\
463 	{						\
464 		.label = _label,			\
465 		.show  = _show,				\
466 		.index = _index,			\
467 	}
468 
469 #define RW_SENSOR_TEMPLATE(_label, _show, _set, _index)	\
470 	{						\
471 		.label = _label,			\
472 		.show  = _show,				\
473 		.set   = _set,				\
474 		.index = _index,			\
475 	}
476 
477 /* Sensor descriptions.  If you add a sensor, update NUM_SENSORS above! */
478 static struct sensor_template meter_attrs[] = {
479 	RO_SENSOR_TEMPLATE(POWER_AVERAGE_NAME, show_power, 0),
480 	RO_SENSOR_TEMPLATE("power1_accuracy", show_accuracy, 0),
481 	RO_SENSOR_TEMPLATE("power1_average_interval_min", show_val, 0),
482 	RO_SENSOR_TEMPLATE("power1_average_interval_max", show_val, 1),
483 	RO_SENSOR_TEMPLATE("power1_is_battery", show_val, 5),
484 	RW_SENSOR_TEMPLATE(POWER_AVG_INTERVAL_NAME, show_avg_interval,
485 		set_avg_interval, 0),
486 	{},
487 };
488 
489 static struct sensor_template misc_cap_attrs[] = {
490 	RO_SENSOR_TEMPLATE("power1_cap_min", show_val, 2),
491 	RO_SENSOR_TEMPLATE("power1_cap_max", show_val, 3),
492 	RO_SENSOR_TEMPLATE("power1_cap_hyst", show_val, 4),
493 	RO_SENSOR_TEMPLATE(POWER_ALARM_NAME, show_val, 6),
494 	{},
495 };
496 
497 static struct sensor_template ro_cap_attrs[] = {
498 	RO_SENSOR_TEMPLATE(POWER_CAP_NAME, show_cap, 0),
499 	{},
500 };
501 
502 static struct sensor_template rw_cap_attrs[] = {
503 	RW_SENSOR_TEMPLATE(POWER_CAP_NAME, show_cap, set_cap, 0),
504 	{},
505 };
506 
507 static struct sensor_template trip_attrs[] = {
508 	RW_SENSOR_TEMPLATE("power1_average_min", show_val, set_trip, 7),
509 	RW_SENSOR_TEMPLATE("power1_average_max", show_val, set_trip, 8),
510 	{},
511 };
512 
513 static struct sensor_template misc_attrs[] = {
514 	RO_SENSOR_TEMPLATE("name", show_name, 0),
515 	RO_SENSOR_TEMPLATE("power1_model_number", show_str, 0),
516 	RO_SENSOR_TEMPLATE("power1_oem_info", show_str, 2),
517 	RO_SENSOR_TEMPLATE("power1_serial_number", show_str, 1),
518 	{},
519 };
520 
521 #undef RO_SENSOR_TEMPLATE
522 #undef RW_SENSOR_TEMPLATE
523 
524 /* Read power domain data */
525 static void remove_domain_devices(struct acpi_power_meter_resource *resource)
526 {
527 	int i;
528 
529 	if (!resource->num_domain_devices)
530 		return;
531 
532 	for (i = 0; i < resource->num_domain_devices; i++) {
533 		struct acpi_device *obj = resource->domain_devices[i];
534 		if (!obj)
535 			continue;
536 
537 		sysfs_remove_link(resource->holders_dir,
538 				  kobject_name(&obj->dev.kobj));
539 		put_device(&obj->dev);
540 	}
541 
542 	kfree(resource->domain_devices);
543 	kobject_put(resource->holders_dir);
544 	resource->num_domain_devices = 0;
545 }
546 
547 static int read_domain_devices(struct acpi_power_meter_resource *resource)
548 {
549 	int res = 0;
550 	int i;
551 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
552 	union acpi_object *pss;
553 	acpi_status status;
554 
555 	status = acpi_evaluate_object(resource->acpi_dev->handle, "_PMD", NULL,
556 				      &buffer);
557 	if (ACPI_FAILURE(status)) {
558 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PMD"));
559 		return -ENODEV;
560 	}
561 
562 	pss = buffer.pointer;
563 	if (!pss ||
564 	    pss->type != ACPI_TYPE_PACKAGE) {
565 		dev_err(&resource->acpi_dev->dev, ACPI_POWER_METER_NAME
566 			"Invalid _PMD data\n");
567 		res = -EFAULT;
568 		goto end;
569 	}
570 
571 	if (!pss->package.count)
572 		goto end;
573 
574 	resource->domain_devices = kzalloc(sizeof(struct acpi_device *) *
575 					   pss->package.count, GFP_KERNEL);
576 	if (!resource->domain_devices) {
577 		res = -ENOMEM;
578 		goto end;
579 	}
580 
581 	resource->holders_dir = kobject_create_and_add("measures",
582 					&resource->acpi_dev->dev.kobj);
583 	if (!resource->holders_dir) {
584 		res = -ENOMEM;
585 		goto exit_free;
586 	}
587 
588 	resource->num_domain_devices = pss->package.count;
589 
590 	for (i = 0; i < pss->package.count; i++) {
591 		struct acpi_device *obj;
592 		union acpi_object *element = &(pss->package.elements[i]);
593 
594 		/* Refuse non-references */
595 		if (element->type != ACPI_TYPE_LOCAL_REFERENCE)
596 			continue;
597 
598 		/* Create a symlink to domain objects */
599 		resource->domain_devices[i] = NULL;
600 		status = acpi_bus_get_device(element->reference.handle,
601 					     &resource->domain_devices[i]);
602 		if (ACPI_FAILURE(status))
603 			continue;
604 
605 		obj = resource->domain_devices[i];
606 		get_device(&obj->dev);
607 
608 		res = sysfs_create_link(resource->holders_dir, &obj->dev.kobj,
609 				      kobject_name(&obj->dev.kobj));
610 		if (res) {
611 			put_device(&obj->dev);
612 			resource->domain_devices[i] = NULL;
613 		}
614 	}
615 
616 	res = 0;
617 	goto end;
618 
619 exit_free:
620 	kfree(resource->domain_devices);
621 end:
622 	kfree(buffer.pointer);
623 	return res;
624 }
625 
626 /* Registration and deregistration */
627 static int register_attrs(struct acpi_power_meter_resource *resource,
628 			  struct sensor_template *attrs)
629 {
630 	struct device *dev = &resource->acpi_dev->dev;
631 	struct sensor_device_attribute *sensors =
632 		&resource->sensors[resource->num_sensors];
633 	int res = 0;
634 
635 	while (attrs->label) {
636 		sensors->dev_attr.attr.name = attrs->label;
637 		sensors->dev_attr.attr.mode = S_IRUGO;
638 		sensors->dev_attr.show = attrs->show;
639 		sensors->index = attrs->index;
640 
641 		if (attrs->set) {
642 			sensors->dev_attr.attr.mode |= S_IWUSR;
643 			sensors->dev_attr.store = attrs->set;
644 		}
645 
646 		sysfs_attr_init(&sensors->dev_attr.attr);
647 		res = device_create_file(dev, &sensors->dev_attr);
648 		if (res) {
649 			sensors->dev_attr.attr.name = NULL;
650 			goto error;
651 		}
652 		sensors++;
653 		resource->num_sensors++;
654 		attrs++;
655 	}
656 
657 error:
658 	return res;
659 }
660 
661 static void remove_attrs(struct acpi_power_meter_resource *resource)
662 {
663 	int i;
664 
665 	for (i = 0; i < resource->num_sensors; i++) {
666 		if (!resource->sensors[i].dev_attr.attr.name)
667 			continue;
668 		device_remove_file(&resource->acpi_dev->dev,
669 				   &resource->sensors[i].dev_attr);
670 	}
671 
672 	remove_domain_devices(resource);
673 
674 	resource->num_sensors = 0;
675 }
676 
677 static int setup_attrs(struct acpi_power_meter_resource *resource)
678 {
679 	int res = 0;
680 
681 	res = read_domain_devices(resource);
682 	if (res)
683 		return res;
684 
685 	if (resource->caps.flags & POWER_METER_CAN_MEASURE) {
686 		res = register_attrs(resource, meter_attrs);
687 		if (res)
688 			goto error;
689 	}
690 
691 	if (resource->caps.flags & POWER_METER_CAN_CAP) {
692 		if (!can_cap_in_hardware()) {
693 			dev_err(&resource->acpi_dev->dev,
694 				"Ignoring unsafe software power cap!\n");
695 			goto skip_unsafe_cap;
696 		}
697 
698 		if (resource->caps.configurable_cap)
699 			res = register_attrs(resource, rw_cap_attrs);
700 		else
701 			res = register_attrs(resource, ro_cap_attrs);
702 
703 		if (res)
704 			goto error;
705 
706 		res = register_attrs(resource, misc_cap_attrs);
707 		if (res)
708 			goto error;
709 	}
710 
711 skip_unsafe_cap:
712 	if (resource->caps.flags & POWER_METER_CAN_TRIP) {
713 		res = register_attrs(resource, trip_attrs);
714 		if (res)
715 			goto error;
716 	}
717 
718 	res = register_attrs(resource, misc_attrs);
719 	if (res)
720 		goto error;
721 
722 	return res;
723 error:
724 	remove_attrs(resource);
725 	return res;
726 }
727 
728 static void free_capabilities(struct acpi_power_meter_resource *resource)
729 {
730 	acpi_string *str;
731 	int i;
732 
733 	str = &resource->model_number;
734 	for (i = 0; i < 3; i++, str++)
735 		kfree(*str);
736 }
737 
738 static int read_capabilities(struct acpi_power_meter_resource *resource)
739 {
740 	int res = 0;
741 	int i;
742 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
743 	struct acpi_buffer state = { 0, NULL };
744 	struct acpi_buffer format = { sizeof("NNNNNNNNNNN"), "NNNNNNNNNNN" };
745 	union acpi_object *pss;
746 	acpi_string *str;
747 	acpi_status status;
748 
749 	status = acpi_evaluate_object(resource->acpi_dev->handle, "_PMC", NULL,
750 				      &buffer);
751 	if (ACPI_FAILURE(status)) {
752 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PMC"));
753 		return -ENODEV;
754 	}
755 
756 	pss = buffer.pointer;
757 	if (!pss ||
758 	    pss->type != ACPI_TYPE_PACKAGE ||
759 	    pss->package.count != 14) {
760 		dev_err(&resource->acpi_dev->dev, ACPI_POWER_METER_NAME
761 			"Invalid _PMC data\n");
762 		res = -EFAULT;
763 		goto end;
764 	}
765 
766 	/* Grab all the integer data at once */
767 	state.length = sizeof(struct acpi_power_meter_capabilities);
768 	state.pointer = &resource->caps;
769 
770 	status = acpi_extract_package(pss, &format, &state);
771 	if (ACPI_FAILURE(status)) {
772 		ACPI_EXCEPTION((AE_INFO, status, "Invalid data"));
773 		res = -EFAULT;
774 		goto end;
775 	}
776 
777 	if (resource->caps.units) {
778 		dev_err(&resource->acpi_dev->dev, ACPI_POWER_METER_NAME
779 			"Unknown units %llu.\n",
780 			resource->caps.units);
781 		res = -EINVAL;
782 		goto end;
783 	}
784 
785 	/* Grab the string data */
786 	str = &resource->model_number;
787 
788 	for (i = 11; i < 14; i++) {
789 		union acpi_object *element = &(pss->package.elements[i]);
790 
791 		if (element->type != ACPI_TYPE_STRING) {
792 			res = -EINVAL;
793 			goto error;
794 		}
795 
796 		*str = kzalloc(sizeof(u8) * (element->string.length + 1),
797 			       GFP_KERNEL);
798 		if (!*str) {
799 			res = -ENOMEM;
800 			goto error;
801 		}
802 
803 		strncpy(*str, element->string.pointer, element->string.length);
804 		str++;
805 	}
806 
807 	dev_info(&resource->acpi_dev->dev, "Found ACPI power meter.\n");
808 	goto end;
809 error:
810 	str = &resource->model_number;
811 	for (i = 0; i < 3; i++, str++)
812 		kfree(*str);
813 end:
814 	kfree(buffer.pointer);
815 	return res;
816 }
817 
818 /* Handle ACPI event notifications */
819 static void acpi_power_meter_notify(struct acpi_device *device, u32 event)
820 {
821 	struct acpi_power_meter_resource *resource;
822 	int res;
823 
824 	if (!device || !acpi_driver_data(device))
825 		return;
826 
827 	resource = acpi_driver_data(device);
828 
829 	mutex_lock(&resource->lock);
830 	switch (event) {
831 	case METER_NOTIFY_CONFIG:
832 		free_capabilities(resource);
833 		res = read_capabilities(resource);
834 		if (res)
835 			break;
836 
837 		remove_attrs(resource);
838 		setup_attrs(resource);
839 		break;
840 	case METER_NOTIFY_TRIP:
841 		sysfs_notify(&device->dev.kobj, NULL, POWER_AVERAGE_NAME);
842 		update_meter(resource);
843 		break;
844 	case METER_NOTIFY_CAP:
845 		sysfs_notify(&device->dev.kobj, NULL, POWER_CAP_NAME);
846 		update_cap(resource);
847 		break;
848 	case METER_NOTIFY_INTERVAL:
849 		sysfs_notify(&device->dev.kobj, NULL, POWER_AVG_INTERVAL_NAME);
850 		update_avg_interval(resource);
851 		break;
852 	case METER_NOTIFY_CAPPING:
853 		sysfs_notify(&device->dev.kobj, NULL, POWER_ALARM_NAME);
854 		dev_info(&device->dev, "Capping in progress.\n");
855 		break;
856 	default:
857 		BUG();
858 	}
859 	mutex_unlock(&resource->lock);
860 
861 	acpi_bus_generate_netlink_event(ACPI_POWER_METER_CLASS,
862 					dev_name(&device->dev), event, 0);
863 }
864 
865 static int acpi_power_meter_add(struct acpi_device *device)
866 {
867 	int res;
868 	struct acpi_power_meter_resource *resource;
869 
870 	if (!device)
871 		return -EINVAL;
872 
873 	resource = kzalloc(sizeof(struct acpi_power_meter_resource),
874 			   GFP_KERNEL);
875 	if (!resource)
876 		return -ENOMEM;
877 
878 	resource->sensors_valid = 0;
879 	resource->acpi_dev = device;
880 	mutex_init(&resource->lock);
881 	strcpy(acpi_device_name(device), ACPI_POWER_METER_DEVICE_NAME);
882 	strcpy(acpi_device_class(device), ACPI_POWER_METER_CLASS);
883 	device->driver_data = resource;
884 
885 	free_capabilities(resource);
886 	res = read_capabilities(resource);
887 	if (res)
888 		goto exit_free;
889 
890 	resource->trip[0] = resource->trip[1] = -1;
891 
892 	res = setup_attrs(resource);
893 	if (res)
894 		goto exit_free;
895 
896 	resource->hwmon_dev = hwmon_device_register(&device->dev);
897 	if (IS_ERR(resource->hwmon_dev)) {
898 		res = PTR_ERR(resource->hwmon_dev);
899 		goto exit_remove;
900 	}
901 
902 	res = 0;
903 	goto exit;
904 
905 exit_remove:
906 	remove_attrs(resource);
907 exit_free:
908 	kfree(resource);
909 exit:
910 	return res;
911 }
912 
913 static int acpi_power_meter_remove(struct acpi_device *device, int type)
914 {
915 	struct acpi_power_meter_resource *resource;
916 
917 	if (!device || !acpi_driver_data(device))
918 		return -EINVAL;
919 
920 	resource = acpi_driver_data(device);
921 	hwmon_device_unregister(resource->hwmon_dev);
922 
923 	free_capabilities(resource);
924 	remove_attrs(resource);
925 
926 	kfree(resource);
927 	return 0;
928 }
929 
930 #ifdef CONFIG_PM_SLEEP
931 
932 static int acpi_power_meter_resume(struct device *dev)
933 {
934 	struct acpi_power_meter_resource *resource;
935 
936 	if (!dev)
937 		return -EINVAL;
938 
939 	resource = acpi_driver_data(to_acpi_device(dev));
940 	if (!resource)
941 		return -EINVAL;
942 
943 	free_capabilities(resource);
944 	read_capabilities(resource);
945 
946 	return 0;
947 }
948 
949 #endif /* CONFIG_PM_SLEEP */
950 
951 static SIMPLE_DEV_PM_OPS(acpi_power_meter_pm, NULL, acpi_power_meter_resume);
952 
953 static struct acpi_driver acpi_power_meter_driver = {
954 	.name = "power_meter",
955 	.class = ACPI_POWER_METER_CLASS,
956 	.ids = power_meter_ids,
957 	.ops = {
958 		.add = acpi_power_meter_add,
959 		.remove = acpi_power_meter_remove,
960 		.notify = acpi_power_meter_notify,
961 		},
962 	.drv.pm = &acpi_power_meter_pm,
963 };
964 
965 /* Module init/exit routines */
966 static int __init enable_cap_knobs(const struct dmi_system_id *d)
967 {
968 	cap_in_hardware = 1;
969 	return 0;
970 }
971 
972 static struct dmi_system_id __initdata pm_dmi_table[] = {
973 	{
974 		enable_cap_knobs, "IBM Active Energy Manager",
975 		{
976 			DMI_MATCH(DMI_SYS_VENDOR, "IBM")
977 		},
978 	},
979 	{}
980 };
981 
982 static int __init acpi_power_meter_init(void)
983 {
984 	int result;
985 
986 	if (acpi_disabled)
987 		return -ENODEV;
988 
989 	dmi_check_system(pm_dmi_table);
990 
991 	result = acpi_bus_register_driver(&acpi_power_meter_driver);
992 	if (result < 0)
993 		return -ENODEV;
994 
995 	return 0;
996 }
997 
998 static void __exit acpi_power_meter_exit(void)
999 {
1000 	acpi_bus_unregister_driver(&acpi_power_meter_driver);
1001 }
1002 
1003 MODULE_AUTHOR("Darrick J. Wong <djwong@us.ibm.com>");
1004 MODULE_DESCRIPTION("ACPI 4.0 power meter driver");
1005 MODULE_LICENSE("GPL");
1006 
1007 module_param(force_cap_on, bool, 0644);
1008 MODULE_PARM_DESC(force_cap_on, "Enable power cap even it is unsafe to do so.");
1009 
1010 module_init(acpi_power_meter_init);
1011 module_exit(acpi_power_meter_exit);
1012