powercap_sys.c 19 KB
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690
/*
 * Power capping class
 * Copyright (c) 2013, Intel Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc.
 *
 */

#include <linux/module.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/powercap.h>

#define to_powercap_zone(n) container_of(n, struct powercap_zone, dev)
#define to_powercap_control_type(n) \
			container_of(n, struct powercap_control_type, dev)

/* Power zone show function */
#define define_power_zone_show(_attr)		\
static ssize_t _attr##_show(struct device *dev, \
					struct device_attribute *dev_attr,\
					char *buf) \
{ \
	u64 value; \
	ssize_t len = -EINVAL; \
	struct powercap_zone *power_zone = to_powercap_zone(dev); \
	\
	if (power_zone->ops->get_##_attr) { \
		if (!power_zone->ops->get_##_attr(power_zone, &value)) \
			len = sprintf(buf, "%lld\n", value); \
	} \
	\
	return len; \
}

/* The only meaningful input is 0 (reset), others are silently ignored */
#define define_power_zone_store(_attr)		\
static ssize_t _attr##_store(struct device *dev,\
				struct device_attribute *dev_attr, \
				const char *buf, size_t count) \
{ \
	int err; \
	struct powercap_zone *power_zone = to_powercap_zone(dev); \
	u64 value; \
	\
	err = kstrtoull(buf, 10, &value); \
	if (err) \
		return -EINVAL; \
	if (value) \
		return count; \
	if (power_zone->ops->reset_##_attr) { \
		if (!power_zone->ops->reset_##_attr(power_zone)) \
			return count; \
	} \
	\
	return -EINVAL; \
}

/* Power zone constraint show function */
#define define_power_zone_constraint_show(_attr) \
static ssize_t show_constraint_##_attr(struct device *dev, \
				struct device_attribute *dev_attr,\
				char *buf) \
{ \
	u64 value; \
	ssize_t len = -ENODATA; \
	struct powercap_zone *power_zone = to_powercap_zone(dev); \
	int id; \
	struct powercap_zone_constraint *pconst;\
	\
	if (!sscanf(dev_attr->attr.name, "constraint_%d_", &id)) \
		return -EINVAL; \
	if (id >= power_zone->const_id_cnt)	\
		return -EINVAL; \
	pconst = &power_zone->constraints[id]; \
	if (pconst && pconst->ops && pconst->ops->get_##_attr) { \
		if (!pconst->ops->get_##_attr(power_zone, id, &value)) \
			len = sprintf(buf, "%lld\n", value); \
	} \
	\
	return len; \
}

/* Power zone constraint store function */
#define define_power_zone_constraint_store(_attr) \
static ssize_t store_constraint_##_attr(struct device *dev,\
				struct device_attribute *dev_attr, \
				const char *buf, size_t count) \
{ \
	int err; \
	u64 value; \
	struct powercap_zone *power_zone = to_powercap_zone(dev); \
	int id; \
	struct powercap_zone_constraint *pconst;\
	\
	if (!sscanf(dev_attr->attr.name, "constraint_%d_", &id)) \
		return -EINVAL; \
	if (id >= power_zone->const_id_cnt)	\
		return -EINVAL; \
	pconst = &power_zone->constraints[id]; \
	err = kstrtoull(buf, 10, &value); \
	if (err) \
		return -EINVAL; \
	if (pconst && pconst->ops && pconst->ops->set_##_attr) { \
		if (!pconst->ops->set_##_attr(power_zone, id, value)) \
			return count; \
	} \
	\
	return -ENODATA; \
}

/* Power zone information callbacks */
define_power_zone_show(power_uw);
define_power_zone_show(max_power_range_uw);
define_power_zone_show(energy_uj);
define_power_zone_store(energy_uj);
define_power_zone_show(max_energy_range_uj);

/* Power zone attributes */
static DEVICE_ATTR_RO(max_power_range_uw);
static DEVICE_ATTR_RO(power_uw);
static DEVICE_ATTR_RO(max_energy_range_uj);
static DEVICE_ATTR_RW(energy_uj);

/* Power zone constraint attributes callbacks */
define_power_zone_constraint_show(power_limit_uw);
define_power_zone_constraint_store(power_limit_uw);
define_power_zone_constraint_show(time_window_us);
define_power_zone_constraint_store(time_window_us);
define_power_zone_constraint_show(max_power_uw);
define_power_zone_constraint_show(min_power_uw);
define_power_zone_constraint_show(max_time_window_us);
define_power_zone_constraint_show(min_time_window_us);

/* For one time seeding of constraint device attributes */
struct powercap_constraint_attr {
	struct device_attribute power_limit_attr;
	struct device_attribute time_window_attr;
	struct device_attribute max_power_attr;
	struct device_attribute min_power_attr;
	struct device_attribute max_time_window_attr;
	struct device_attribute min_time_window_attr;
	struct device_attribute name_attr;
};

static struct powercap_constraint_attr
				constraint_attrs[MAX_CONSTRAINTS_PER_ZONE];

/* A list of powercap control_types */
static LIST_HEAD(powercap_cntrl_list);
/* Mutex to protect list of powercap control_types */
static DEFINE_MUTEX(powercap_cntrl_list_lock);

#define POWERCAP_CONSTRAINT_NAME_LEN	30 /* Some limit to avoid overflow */
static ssize_t show_constraint_name(struct device *dev,
				struct device_attribute *dev_attr,
				char *buf)
{
	const char *name;
	struct powercap_zone *power_zone = to_powercap_zone(dev);
	int id;
	ssize_t len = -ENODATA;
	struct powercap_zone_constraint *pconst;

	if (!sscanf(dev_attr->attr.name, "constraint_%d_", &id))
		return -EINVAL;
	if (id >= power_zone->const_id_cnt)
		return -EINVAL;
	pconst = &power_zone->constraints[id];

	if (pconst && pconst->ops && pconst->ops->get_name) {
		name = pconst->ops->get_name(power_zone, id);
		if (name) {
			snprintf(buf, POWERCAP_CONSTRAINT_NAME_LEN,
								"%s\n", name);
			buf[POWERCAP_CONSTRAINT_NAME_LEN] = '\0';
			len = strlen(buf);
		}
	}

	return len;
}

static int create_constraint_attribute(int id, const char *name,
				int mode,
				struct device_attribute *dev_attr,
				ssize_t (*show)(struct device *,
					struct device_attribute *, char *),
				ssize_t (*store)(struct device *,
					struct device_attribute *,
				const char *, size_t)
				)
{

	dev_attr->attr.name = kasprintf(GFP_KERNEL, "constraint_%d_%s",
								id, name);
	if (!dev_attr->attr.name)
		return -ENOMEM;
	dev_attr->attr.mode = mode;
	dev_attr->show = show;
	dev_attr->store = store;

	return 0;
}

static void free_constraint_attributes(void)
{
	int i;

	for (i = 0; i < MAX_CONSTRAINTS_PER_ZONE; ++i) {
		kfree(constraint_attrs[i].power_limit_attr.attr.name);
		kfree(constraint_attrs[i].time_window_attr.attr.name);
		kfree(constraint_attrs[i].name_attr.attr.name);
		kfree(constraint_attrs[i].max_power_attr.attr.name);
		kfree(constraint_attrs[i].min_power_attr.attr.name);
		kfree(constraint_attrs[i].max_time_window_attr.attr.name);
		kfree(constraint_attrs[i].min_time_window_attr.attr.name);
	}
}

static int seed_constraint_attributes(void)
{
	int i;
	int ret;

	for (i = 0; i < MAX_CONSTRAINTS_PER_ZONE; ++i) {
		ret = create_constraint_attribute(i, "power_limit_uw",
					S_IWUSR | S_IRUGO,
					&constraint_attrs[i].power_limit_attr,
					show_constraint_power_limit_uw,
					store_constraint_power_limit_uw);
		if (ret)
			goto err_alloc;
		ret = create_constraint_attribute(i, "time_window_us",
					S_IWUSR | S_IRUGO,
					&constraint_attrs[i].time_window_attr,
					show_constraint_time_window_us,
					store_constraint_time_window_us);
		if (ret)
			goto err_alloc;
		ret = create_constraint_attribute(i, "name", S_IRUGO,
				&constraint_attrs[i].name_attr,
				show_constraint_name,
				NULL);
		if (ret)
			goto err_alloc;
		ret = create_constraint_attribute(i, "max_power_uw", S_IRUGO,
				&constraint_attrs[i].max_power_attr,
				show_constraint_max_power_uw,
				NULL);
		if (ret)
			goto err_alloc;
		ret = create_constraint_attribute(i, "min_power_uw", S_IRUGO,
				&constraint_attrs[i].min_power_attr,
				show_constraint_min_power_uw,
				NULL);
		if (ret)
			goto err_alloc;
		ret = create_constraint_attribute(i, "max_time_window_us",
				S_IRUGO,
				&constraint_attrs[i].max_time_window_attr,
				show_constraint_max_time_window_us,
				NULL);
		if (ret)
			goto err_alloc;
		ret = create_constraint_attribute(i, "min_time_window_us",
				S_IRUGO,
				&constraint_attrs[i].min_time_window_attr,
				show_constraint_min_time_window_us,
				NULL);
		if (ret)
			goto err_alloc;

	}

	return 0;

err_alloc:
	free_constraint_attributes();

	return ret;
}

static int create_constraints(struct powercap_zone *power_zone,
				int nr_constraints,
				struct powercap_zone_constraint_ops *const_ops)
{
	int i;
	int ret = 0;
	int count;
	struct powercap_zone_constraint *pconst;

	if (!power_zone || !const_ops || !const_ops->get_power_limit_uw ||
					!const_ops->set_power_limit_uw ||
					!const_ops->get_time_window_us ||
					!const_ops->set_time_window_us)
		return -EINVAL;

	count = power_zone->zone_attr_count;
	for (i = 0; i < nr_constraints; ++i) {
		pconst = &power_zone->constraints[i];
		pconst->ops = const_ops;
		pconst->id = power_zone->const_id_cnt;
		power_zone->const_id_cnt++;
		power_zone->zone_dev_attrs[count++] =
				&constraint_attrs[i].power_limit_attr.attr;
		power_zone->zone_dev_attrs[count++] =
				&constraint_attrs[i].time_window_attr.attr;
		if (pconst->ops->get_name)
			power_zone->zone_dev_attrs[count++] =
				&constraint_attrs[i].name_attr.attr;
		if (pconst->ops->get_max_power_uw)
			power_zone->zone_dev_attrs[count++] =
				&constraint_attrs[i].max_power_attr.attr;
		if (pconst->ops->get_min_power_uw)
			power_zone->zone_dev_attrs[count++] =
				&constraint_attrs[i].min_power_attr.attr;
		if (pconst->ops->get_max_time_window_us)
			power_zone->zone_dev_attrs[count++] =
				&constraint_attrs[i].max_time_window_attr.attr;
		if (pconst->ops->get_min_time_window_us)
			power_zone->zone_dev_attrs[count++] =
				&constraint_attrs[i].min_time_window_attr.attr;
	}
	power_zone->zone_attr_count = count;

	return ret;
}

static bool control_type_valid(void *control_type)
{
	struct powercap_control_type *pos = NULL;
	bool found = false;

	mutex_lock(&powercap_cntrl_list_lock);

	list_for_each_entry(pos, &powercap_cntrl_list, node) {
		if (pos == control_type) {
			found = true;
			break;
		}
	}
	mutex_unlock(&powercap_cntrl_list_lock);

	return found;
}

static ssize_t name_show(struct device *dev,
				struct device_attribute *attr,
				char *buf)
{
	struct powercap_zone *power_zone = to_powercap_zone(dev);

	return sprintf(buf, "%s\n", power_zone->name);
}

static DEVICE_ATTR_RO(name);

/* Create zone and attributes in sysfs */
static void create_power_zone_common_attributes(
					struct powercap_zone *power_zone)
{
	int count = 0;

	power_zone->zone_dev_attrs[count++] = &dev_attr_name.attr;
	if (power_zone->ops->get_max_energy_range_uj)
		power_zone->zone_dev_attrs[count++] =
					&dev_attr_max_energy_range_uj.attr;
	if (power_zone->ops->get_energy_uj) {
		if (power_zone->ops->reset_energy_uj)
			dev_attr_energy_uj.attr.mode = S_IWUSR | S_IRUGO;
		else
			dev_attr_energy_uj.attr.mode = S_IRUGO;
		power_zone->zone_dev_attrs[count++] =
					&dev_attr_energy_uj.attr;
	}
	if (power_zone->ops->get_power_uw)
		power_zone->zone_dev_attrs[count++] =
					&dev_attr_power_uw.attr;
	if (power_zone->ops->get_max_power_range_uw)
		power_zone->zone_dev_attrs[count++] =
					&dev_attr_max_power_range_uw.attr;
	power_zone->zone_dev_attrs[count] = NULL;
	power_zone->zone_attr_count = count;
}

static void powercap_release(struct device *dev)
{
	bool allocated;

	if (dev->parent) {
		struct powercap_zone *power_zone = to_powercap_zone(dev);

		/* Store flag as the release() may free memory */
		allocated = power_zone->allocated;
		/* Remove id from parent idr struct */
		idr_remove(power_zone->parent_idr, power_zone->id);
		/* Destroy idrs allocated for this zone */
		idr_destroy(&power_zone->idr);
		kfree(power_zone->name);
		kfree(power_zone->zone_dev_attrs);
		kfree(power_zone->constraints);
		if (power_zone->ops->release)
			power_zone->ops->release(power_zone);
		if (allocated)
			kfree(power_zone);
	} else {
		struct powercap_control_type *control_type =
						to_powercap_control_type(dev);

		/* Store flag as the release() may free memory */
		allocated = control_type->allocated;
		idr_destroy(&control_type->idr);
		mutex_destroy(&control_type->lock);
		if (control_type->ops && control_type->ops->release)
			control_type->ops->release(control_type);
		if (allocated)
			kfree(control_type);
	}
}

static ssize_t enabled_show(struct device *dev,
				struct device_attribute *attr,
				char *buf)
{
	bool mode = true;

	/* Default is enabled */
	if (dev->parent) {
		struct powercap_zone *power_zone = to_powercap_zone(dev);
		if (power_zone->ops->get_enable)
			if (power_zone->ops->get_enable(power_zone, &mode))
				mode = false;
	} else {
		struct powercap_control_type *control_type =
						to_powercap_control_type(dev);
		if (control_type->ops && control_type->ops->get_enable)
			if (control_type->ops->get_enable(control_type, &mode))
				mode = false;
	}

	return sprintf(buf, "%d\n", mode);
}

static ssize_t enabled_store(struct device *dev,
				struct device_attribute *attr,
				const char *buf,  size_t len)
{
	bool mode;

	if (strtobool(buf, &mode))
		return -EINVAL;
	if (dev->parent) {
		struct powercap_zone *power_zone = to_powercap_zone(dev);
		if (power_zone->ops->set_enable)
			if (!power_zone->ops->set_enable(power_zone, mode))
				return len;
	} else {
		struct powercap_control_type *control_type =
						to_powercap_control_type(dev);
		if (control_type->ops && control_type->ops->set_enable)
			if (!control_type->ops->set_enable(control_type, mode))
				return len;
	}

	return -ENOSYS;
}

static DEVICE_ATTR_RW(enabled);

static struct attribute *powercap_attrs[] = {
	&dev_attr_enabled.attr,
	NULL,
};
ATTRIBUTE_GROUPS(powercap);

static struct class powercap_class = {
	.name = "powercap",
	.dev_release = powercap_release,
	.dev_groups = powercap_groups,
};

struct powercap_zone *powercap_register_zone(
				struct powercap_zone *power_zone,
				struct powercap_control_type *control_type,
				const char *name,
				struct powercap_zone *parent,
				const struct powercap_zone_ops *ops,
				int nr_constraints,
				struct powercap_zone_constraint_ops *const_ops)
{
	int result;
	int nr_attrs;

	if (!name || !control_type || !ops ||
			nr_constraints > MAX_CONSTRAINTS_PER_ZONE ||
			(!ops->get_energy_uj && !ops->get_power_uw) ||
			!control_type_valid(control_type))
		return ERR_PTR(-EINVAL);

	if (power_zone) {
		if (!ops->release)
			return ERR_PTR(-EINVAL);
		memset(power_zone, 0, sizeof(*power_zone));
	} else {
		power_zone = kzalloc(sizeof(*power_zone), GFP_KERNEL);
		if (!power_zone)
			return ERR_PTR(-ENOMEM);
		power_zone->allocated = true;
	}
	power_zone->ops = ops;
	power_zone->control_type_inst = control_type;
	if (!parent) {
		power_zone->dev.parent = &control_type->dev;
		power_zone->parent_idr = &control_type->idr;
	} else {
		power_zone->dev.parent = &parent->dev;
		power_zone->parent_idr = &parent->idr;
	}
	power_zone->dev.class = &powercap_class;

	mutex_lock(&control_type->lock);
	/* Using idr to get the unique id */
	result = idr_alloc(power_zone->parent_idr, NULL, 0, 0, GFP_KERNEL);
	if (result < 0)
		goto err_idr_alloc;

	power_zone->id = result;
	idr_init(&power_zone->idr);
	power_zone->name = kstrdup(name, GFP_KERNEL);
	if (!power_zone->name)
		goto err_name_alloc;
	dev_set_name(&power_zone->dev, "%s:%x",
					dev_name(power_zone->dev.parent),
					power_zone->id);
	power_zone->constraints = kzalloc(sizeof(*power_zone->constraints) *
					 nr_constraints, GFP_KERNEL);
	if (!power_zone->constraints)
		goto err_const_alloc;

	nr_attrs = nr_constraints * POWERCAP_CONSTRAINTS_ATTRS +
						POWERCAP_ZONE_MAX_ATTRS + 1;
	power_zone->zone_dev_attrs = kzalloc(sizeof(void *) *
						nr_attrs, GFP_KERNEL);
	if (!power_zone->zone_dev_attrs)
		goto err_attr_alloc;
	create_power_zone_common_attributes(power_zone);
	result = create_constraints(power_zone, nr_constraints, const_ops);
	if (result)
		goto err_dev_ret;

	power_zone->zone_dev_attrs[power_zone->zone_attr_count] = NULL;
	power_zone->dev_zone_attr_group.attrs = power_zone->zone_dev_attrs;
	power_zone->dev_attr_groups[0] = &power_zone->dev_zone_attr_group;
	power_zone->dev_attr_groups[1] = NULL;
	power_zone->dev.groups = power_zone->dev_attr_groups;
	result = device_register(&power_zone->dev);
	if (result)
		goto err_dev_ret;

	control_type->nr_zones++;
	mutex_unlock(&control_type->lock);

	return power_zone;

err_dev_ret:
	kfree(power_zone->zone_dev_attrs);
err_attr_alloc:
	kfree(power_zone->constraints);
err_const_alloc:
	kfree(power_zone->name);
err_name_alloc:
	idr_remove(power_zone->parent_idr, power_zone->id);
err_idr_alloc:
	if (power_zone->allocated)
		kfree(power_zone);
	mutex_unlock(&control_type->lock);

	return ERR_PTR(result);
}
EXPORT_SYMBOL_GPL(powercap_register_zone);

int powercap_unregister_zone(struct powercap_control_type *control_type,
				struct powercap_zone *power_zone)
{
	if (!power_zone || !control_type)
		return -EINVAL;

	mutex_lock(&control_type->lock);
	control_type->nr_zones--;
	mutex_unlock(&control_type->lock);

	device_unregister(&power_zone->dev);

	return 0;
}
EXPORT_SYMBOL_GPL(powercap_unregister_zone);

struct powercap_control_type *powercap_register_control_type(
				struct powercap_control_type *control_type,
				const char *name,
				const struct powercap_control_type_ops *ops)
{
	int result;

	if (!name)
		return ERR_PTR(-EINVAL);
	if (control_type) {
		if (!ops || !ops->release)
			return ERR_PTR(-EINVAL);
		memset(control_type, 0, sizeof(*control_type));
	} else {
		control_type = kzalloc(sizeof(*control_type), GFP_KERNEL);
		if (!control_type)
			return ERR_PTR(-ENOMEM);
		control_type->allocated = true;
	}
	mutex_init(&control_type->lock);
	control_type->ops = ops;
	INIT_LIST_HEAD(&control_type->node);
	control_type->dev.class = &powercap_class;
	dev_set_name(&control_type->dev, "%s", name);
	result = device_register(&control_type->dev);
	if (result) {
		if (control_type->allocated)
			kfree(control_type);
		return ERR_PTR(result);
	}
	idr_init(&control_type->idr);

	mutex_lock(&powercap_cntrl_list_lock);
	list_add_tail(&control_type->node, &powercap_cntrl_list);
	mutex_unlock(&powercap_cntrl_list_lock);

	return control_type;
}
EXPORT_SYMBOL_GPL(powercap_register_control_type);

int powercap_unregister_control_type(struct powercap_control_type *control_type)
{
	struct powercap_control_type *pos = NULL;

	if (control_type->nr_zones) {
		dev_err(&control_type->dev, "Zones of this type still not freed\n");
		return -EINVAL;
	}
	mutex_lock(&powercap_cntrl_list_lock);
	list_for_each_entry(pos, &powercap_cntrl_list, node) {
		if (pos == control_type) {
			list_del(&control_type->node);
			mutex_unlock(&powercap_cntrl_list_lock);
			device_unregister(&control_type->dev);
			return 0;
		}
	}
	mutex_unlock(&powercap_cntrl_list_lock);

	return -ENODEV;
}
EXPORT_SYMBOL_GPL(powercap_unregister_control_type);

static int __init powercap_init(void)
{
	int result = 0;

	result = seed_constraint_attributes();
	if (result)
		return result;

	result = class_register(&powercap_class);

	return result;
}

device_initcall(powercap_init);

MODULE_DESCRIPTION("PowerCap sysfs Driver");
MODULE_AUTHOR("Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>");
MODULE_LICENSE("GPL v2");