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"
  36ACPI_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
  60static int cap_in_hardware;
  61static bool force_cap_on;
  62
  63static int can_cap_in_hardware(void)
  64{
  65	return force_cap_on || cap_in_hardware;
  66}
  67
  68static const struct acpi_device_id power_meter_ids[] = {
  69	{"ACPI000D", 0},
  70	{"", 0},
  71};
  72MODULE_DEVICE_TABLE(acpi, power_meter_ids);
  73
  74struct 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
  88struct 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
 110struct 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 */
 122static 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
 138static 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
 152static 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 */
 194static 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
 210static 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
 224static 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 */
 265static 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
 297static 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 */
 324static 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
 348static 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 */
 363static 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
 392static 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
 448static 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
 459static 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! */
 482static 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
 493static 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
 501static struct sensor_template ro_cap_attrs[] = {
 502	RO_SENSOR_TEMPLATE(POWER_CAP_NAME, show_cap, 0),
 503	{},
 504};
 505
 506static struct sensor_template rw_cap_attrs[] = {
 507	RW_SENSOR_TEMPLATE(POWER_CAP_NAME, show_cap, set_cap, 0),
 508	{},
 509};
 510
 511static 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
 517static 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 */
 529static 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
 551static 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
 622exit_free:
 623	kfree(resource->domain_devices);
 624end:
 625	kfree(buffer.pointer);
 626	return res;
 627}
 628
 629/* Registration and deregistration */
 630static 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
 660error:
 661	return res;
 662}
 663
 664static 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
 680static 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
 714skip_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;
 726error:
 727	remove_attrs(resource);
 728	return res;
 729}
 730
 731static 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
 741static 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;
 812error:
 813	str = &resource->model_number;
 814	for (i = 0; i < 3; i++, str++)
 815		kfree(*str);
 816end:
 817	kfree(buffer.pointer);
 818	return res;
 819}
 820
 821/* Handle ACPI event notifications */
 822static 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
 869static 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
 909exit_remove:
 910	remove_attrs(resource);
 911exit_free:
 912	kfree(resource);
 913exit:
 914	return res;
 915}
 916
 917static 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
 936static 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
 955static SIMPLE_DEV_PM_OPS(acpi_power_meter_pm, NULL, acpi_power_meter_resume);
 956
 957static 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 */
 970static int __init enable_cap_knobs(const struct dmi_system_id *d)
 971{
 972	cap_in_hardware = 1;
 973	return 0;
 974}
 975
 976static 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
 986static 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
1002static void __exit acpi_power_meter_exit(void)
1003{
1004	acpi_bus_unregister_driver(&acpi_power_meter_driver);
1005}
1006
1007MODULE_AUTHOR("Darrick J. Wong <darrick.wong@oracle.com>");
1008MODULE_DESCRIPTION("ACPI 4.0 power meter driver");
1009MODULE_LICENSE("GPL");
1010
1011module_param(force_cap_on, bool, 0644);
1012MODULE_PARM_DESC(force_cap_on, "Enable power cap even it is unsafe to do so.");
1013
1014module_init(acpi_power_meter_init);
1015module_exit(acpi_power_meter_exit);