linux/drivers/powercap/powercap_sys.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Power capping class
   4 * Copyright (c) 2013, Intel Corporation.
   5 */
   6
   7#include <linux/module.h>
   8#include <linux/device.h>
   9#include <linux/err.h>
  10#include <linux/slab.h>
  11#include <linux/powercap.h>
  12
  13#define to_powercap_zone(n) container_of(n, struct powercap_zone, dev)
  14#define to_powercap_control_type(n) \
  15                        container_of(n, struct powercap_control_type, dev)
  16
  17/* Power zone show function */
  18#define define_power_zone_show(_attr)           \
  19static ssize_t _attr##_show(struct device *dev, \
  20                                        struct device_attribute *dev_attr,\
  21                                        char *buf) \
  22{ \
  23        u64 value; \
  24        ssize_t len = -EINVAL; \
  25        struct powercap_zone *power_zone = to_powercap_zone(dev); \
  26        \
  27        if (power_zone->ops->get_##_attr) { \
  28                if (!power_zone->ops->get_##_attr(power_zone, &value)) \
  29                        len = sprintf(buf, "%lld\n", value); \
  30        } \
  31        \
  32        return len; \
  33}
  34
  35/* The only meaningful input is 0 (reset), others are silently ignored */
  36#define define_power_zone_store(_attr)          \
  37static ssize_t _attr##_store(struct device *dev,\
  38                                struct device_attribute *dev_attr, \
  39                                const char *buf, size_t count) \
  40{ \
  41        int err; \
  42        struct powercap_zone *power_zone = to_powercap_zone(dev); \
  43        u64 value; \
  44        \
  45        err = kstrtoull(buf, 10, &value); \
  46        if (err) \
  47                return -EINVAL; \
  48        if (value) \
  49                return count; \
  50        if (power_zone->ops->reset_##_attr) { \
  51                if (!power_zone->ops->reset_##_attr(power_zone)) \
  52                        return count; \
  53        } \
  54        \
  55        return -EINVAL; \
  56}
  57
  58/* Power zone constraint show function */
  59#define define_power_zone_constraint_show(_attr) \
  60static ssize_t show_constraint_##_attr(struct device *dev, \
  61                                struct device_attribute *dev_attr,\
  62                                char *buf) \
  63{ \
  64        u64 value; \
  65        ssize_t len = -ENODATA; \
  66        struct powercap_zone *power_zone = to_powercap_zone(dev); \
  67        int id; \
  68        struct powercap_zone_constraint *pconst;\
  69        \
  70        if (!sscanf(dev_attr->attr.name, "constraint_%d_", &id)) \
  71                return -EINVAL; \
  72        if (id >= power_zone->const_id_cnt)     \
  73                return -EINVAL; \
  74        pconst = &power_zone->constraints[id]; \
  75        if (pconst && pconst->ops && pconst->ops->get_##_attr) { \
  76                if (!pconst->ops->get_##_attr(power_zone, id, &value)) \
  77                        len = sprintf(buf, "%lld\n", value); \
  78        } \
  79        \
  80        return len; \
  81}
  82
  83/* Power zone constraint store function */
  84#define define_power_zone_constraint_store(_attr) \
  85static ssize_t store_constraint_##_attr(struct device *dev,\
  86                                struct device_attribute *dev_attr, \
  87                                const char *buf, size_t count) \
  88{ \
  89        int err; \
  90        u64 value; \
  91        struct powercap_zone *power_zone = to_powercap_zone(dev); \
  92        int id; \
  93        struct powercap_zone_constraint *pconst;\
  94        \
  95        if (!sscanf(dev_attr->attr.name, "constraint_%d_", &id)) \
  96                return -EINVAL; \
  97        if (id >= power_zone->const_id_cnt)     \
  98                return -EINVAL; \
  99        pconst = &power_zone->constraints[id]; \
 100        err = kstrtoull(buf, 10, &value); \
 101        if (err) \
 102                return -EINVAL; \
 103        if (pconst && pconst->ops && pconst->ops->set_##_attr) { \
 104                if (!pconst->ops->set_##_attr(power_zone, id, value)) \
 105                        return count; \
 106        } \
 107        \
 108        return -ENODATA; \
 109}
 110
 111/* Power zone information callbacks */
 112define_power_zone_show(power_uw);
 113define_power_zone_show(max_power_range_uw);
 114define_power_zone_show(energy_uj);
 115define_power_zone_store(energy_uj);
 116define_power_zone_show(max_energy_range_uj);
 117
 118/* Power zone attributes */
 119static DEVICE_ATTR_RO(max_power_range_uw);
 120static DEVICE_ATTR_RO(power_uw);
 121static DEVICE_ATTR_RO(max_energy_range_uj);
 122static DEVICE_ATTR_RW(energy_uj);
 123
 124/* Power zone constraint attributes callbacks */
 125define_power_zone_constraint_show(power_limit_uw);
 126define_power_zone_constraint_store(power_limit_uw);
 127define_power_zone_constraint_show(time_window_us);
 128define_power_zone_constraint_store(time_window_us);
 129define_power_zone_constraint_show(max_power_uw);
 130define_power_zone_constraint_show(min_power_uw);
 131define_power_zone_constraint_show(max_time_window_us);
 132define_power_zone_constraint_show(min_time_window_us);
 133
 134/* For one time seeding of constraint device attributes */
 135struct powercap_constraint_attr {
 136        struct device_attribute power_limit_attr;
 137        struct device_attribute time_window_attr;
 138        struct device_attribute max_power_attr;
 139        struct device_attribute min_power_attr;
 140        struct device_attribute max_time_window_attr;
 141        struct device_attribute min_time_window_attr;
 142        struct device_attribute name_attr;
 143};
 144
 145static struct powercap_constraint_attr
 146                                constraint_attrs[MAX_CONSTRAINTS_PER_ZONE];
 147
 148/* A list of powercap control_types */
 149static LIST_HEAD(powercap_cntrl_list);
 150/* Mutex to protect list of powercap control_types */
 151static DEFINE_MUTEX(powercap_cntrl_list_lock);
 152
 153#define POWERCAP_CONSTRAINT_NAME_LEN    30 /* Some limit to avoid overflow */
 154static ssize_t show_constraint_name(struct device *dev,
 155                                struct device_attribute *dev_attr,
 156                                char *buf)
 157{
 158        const char *name;
 159        struct powercap_zone *power_zone = to_powercap_zone(dev);
 160        int id;
 161        ssize_t len = -ENODATA;
 162        struct powercap_zone_constraint *pconst;
 163
 164        if (!sscanf(dev_attr->attr.name, "constraint_%d_", &id))
 165                return -EINVAL;
 166        if (id >= power_zone->const_id_cnt)
 167                return -EINVAL;
 168        pconst = &power_zone->constraints[id];
 169
 170        if (pconst && pconst->ops && pconst->ops->get_name) {
 171                name = pconst->ops->get_name(power_zone, id);
 172                if (name) {
 173                        snprintf(buf, POWERCAP_CONSTRAINT_NAME_LEN,
 174                                                                "%s\n", name);
 175                        buf[POWERCAP_CONSTRAINT_NAME_LEN] = '\0';
 176                        len = strlen(buf);
 177                }
 178        }
 179
 180        return len;
 181}
 182
 183static int create_constraint_attribute(int id, const char *name,
 184                                int mode,
 185                                struct device_attribute *dev_attr,
 186                                ssize_t (*show)(struct device *,
 187                                        struct device_attribute *, char *),
 188                                ssize_t (*store)(struct device *,
 189                                        struct device_attribute *,
 190                                const char *, size_t)
 191                                )
 192{
 193
 194        dev_attr->attr.name = kasprintf(GFP_KERNEL, "constraint_%d_%s",
 195                                                                id, name);
 196        if (!dev_attr->attr.name)
 197                return -ENOMEM;
 198        dev_attr->attr.mode = mode;
 199        dev_attr->show = show;
 200        dev_attr->store = store;
 201
 202        return 0;
 203}
 204
 205static void free_constraint_attributes(void)
 206{
 207        int i;
 208
 209        for (i = 0; i < MAX_CONSTRAINTS_PER_ZONE; ++i) {
 210                kfree(constraint_attrs[i].power_limit_attr.attr.name);
 211                kfree(constraint_attrs[i].time_window_attr.attr.name);
 212                kfree(constraint_attrs[i].name_attr.attr.name);
 213                kfree(constraint_attrs[i].max_power_attr.attr.name);
 214                kfree(constraint_attrs[i].min_power_attr.attr.name);
 215                kfree(constraint_attrs[i].max_time_window_attr.attr.name);
 216                kfree(constraint_attrs[i].min_time_window_attr.attr.name);
 217        }
 218}
 219
 220static int seed_constraint_attributes(void)
 221{
 222        int i;
 223        int ret;
 224
 225        for (i = 0; i < MAX_CONSTRAINTS_PER_ZONE; ++i) {
 226                ret = create_constraint_attribute(i, "power_limit_uw",
 227                                        S_IWUSR | S_IRUGO,
 228                                        &constraint_attrs[i].power_limit_attr,
 229                                        show_constraint_power_limit_uw,
 230                                        store_constraint_power_limit_uw);
 231                if (ret)
 232                        goto err_alloc;
 233                ret = create_constraint_attribute(i, "time_window_us",
 234                                        S_IWUSR | S_IRUGO,
 235                                        &constraint_attrs[i].time_window_attr,
 236                                        show_constraint_time_window_us,
 237                                        store_constraint_time_window_us);
 238                if (ret)
 239                        goto err_alloc;
 240                ret = create_constraint_attribute(i, "name", S_IRUGO,
 241                                &constraint_attrs[i].name_attr,
 242                                show_constraint_name,
 243                                NULL);
 244                if (ret)
 245                        goto err_alloc;
 246                ret = create_constraint_attribute(i, "max_power_uw", S_IRUGO,
 247                                &constraint_attrs[i].max_power_attr,
 248                                show_constraint_max_power_uw,
 249                                NULL);
 250                if (ret)
 251                        goto err_alloc;
 252                ret = create_constraint_attribute(i, "min_power_uw", S_IRUGO,
 253                                &constraint_attrs[i].min_power_attr,
 254                                show_constraint_min_power_uw,
 255                                NULL);
 256                if (ret)
 257                        goto err_alloc;
 258                ret = create_constraint_attribute(i, "max_time_window_us",
 259                                S_IRUGO,
 260                                &constraint_attrs[i].max_time_window_attr,
 261                                show_constraint_max_time_window_us,
 262                                NULL);
 263                if (ret)
 264                        goto err_alloc;
 265                ret = create_constraint_attribute(i, "min_time_window_us",
 266                                S_IRUGO,
 267                                &constraint_attrs[i].min_time_window_attr,
 268                                show_constraint_min_time_window_us,
 269                                NULL);
 270                if (ret)
 271                        goto err_alloc;
 272
 273        }
 274
 275        return 0;
 276
 277err_alloc:
 278        free_constraint_attributes();
 279
 280        return ret;
 281}
 282
 283static int create_constraints(struct powercap_zone *power_zone,
 284                        int nr_constraints,
 285                        const struct powercap_zone_constraint_ops *const_ops)
 286{
 287        int i;
 288        int ret = 0;
 289        int count;
 290        struct powercap_zone_constraint *pconst;
 291
 292        if (!power_zone || !const_ops || !const_ops->get_power_limit_uw ||
 293                                        !const_ops->set_power_limit_uw ||
 294                                        !const_ops->get_time_window_us ||
 295                                        !const_ops->set_time_window_us)
 296                return -EINVAL;
 297
 298        count = power_zone->zone_attr_count;
 299        for (i = 0; i < nr_constraints; ++i) {
 300                pconst = &power_zone->constraints[i];
 301                pconst->ops = const_ops;
 302                pconst->id = power_zone->const_id_cnt;
 303                power_zone->const_id_cnt++;
 304                power_zone->zone_dev_attrs[count++] =
 305                                &constraint_attrs[i].power_limit_attr.attr;
 306                power_zone->zone_dev_attrs[count++] =
 307                                &constraint_attrs[i].time_window_attr.attr;
 308                if (pconst->ops->get_name)
 309                        power_zone->zone_dev_attrs[count++] =
 310                                &constraint_attrs[i].name_attr.attr;
 311                if (pconst->ops->get_max_power_uw)
 312                        power_zone->zone_dev_attrs[count++] =
 313                                &constraint_attrs[i].max_power_attr.attr;
 314                if (pconst->ops->get_min_power_uw)
 315                        power_zone->zone_dev_attrs[count++] =
 316                                &constraint_attrs[i].min_power_attr.attr;
 317                if (pconst->ops->get_max_time_window_us)
 318                        power_zone->zone_dev_attrs[count++] =
 319                                &constraint_attrs[i].max_time_window_attr.attr;
 320                if (pconst->ops->get_min_time_window_us)
 321                        power_zone->zone_dev_attrs[count++] =
 322                                &constraint_attrs[i].min_time_window_attr.attr;
 323        }
 324        power_zone->zone_attr_count = count;
 325
 326        return ret;
 327}
 328
 329static bool control_type_valid(void *control_type)
 330{
 331        struct powercap_control_type *pos = NULL;
 332        bool found = false;
 333
 334        mutex_lock(&powercap_cntrl_list_lock);
 335
 336        list_for_each_entry(pos, &powercap_cntrl_list, node) {
 337                if (pos == control_type) {
 338                        found = true;
 339                        break;
 340                }
 341        }
 342        mutex_unlock(&powercap_cntrl_list_lock);
 343
 344        return found;
 345}
 346
 347static ssize_t name_show(struct device *dev,
 348                                struct device_attribute *attr,
 349                                char *buf)
 350{
 351        struct powercap_zone *power_zone = to_powercap_zone(dev);
 352
 353        return sprintf(buf, "%s\n", power_zone->name);
 354}
 355
 356static DEVICE_ATTR_RO(name);
 357
 358/* Create zone and attributes in sysfs */
 359static void create_power_zone_common_attributes(
 360                                        struct powercap_zone *power_zone)
 361{
 362        int count = 0;
 363
 364        power_zone->zone_dev_attrs[count++] = &dev_attr_name.attr;
 365        if (power_zone->ops->get_max_energy_range_uj)
 366                power_zone->zone_dev_attrs[count++] =
 367                                        &dev_attr_max_energy_range_uj.attr;
 368        if (power_zone->ops->get_energy_uj) {
 369                if (power_zone->ops->reset_energy_uj)
 370                        dev_attr_energy_uj.attr.mode = S_IWUSR | S_IRUGO;
 371                else
 372                        dev_attr_energy_uj.attr.mode = S_IRUGO;
 373                power_zone->zone_dev_attrs[count++] =
 374                                        &dev_attr_energy_uj.attr;
 375        }
 376        if (power_zone->ops->get_power_uw)
 377                power_zone->zone_dev_attrs[count++] =
 378                                        &dev_attr_power_uw.attr;
 379        if (power_zone->ops->get_max_power_range_uw)
 380                power_zone->zone_dev_attrs[count++] =
 381                                        &dev_attr_max_power_range_uw.attr;
 382        power_zone->zone_dev_attrs[count] = NULL;
 383        power_zone->zone_attr_count = count;
 384}
 385
 386static void powercap_release(struct device *dev)
 387{
 388        bool allocated;
 389
 390        if (dev->parent) {
 391                struct powercap_zone *power_zone = to_powercap_zone(dev);
 392
 393                /* Store flag as the release() may free memory */
 394                allocated = power_zone->allocated;
 395                /* Remove id from parent idr struct */
 396                idr_remove(power_zone->parent_idr, power_zone->id);
 397                /* Destroy idrs allocated for this zone */
 398                idr_destroy(&power_zone->idr);
 399                kfree(power_zone->name);
 400                kfree(power_zone->zone_dev_attrs);
 401                kfree(power_zone->constraints);
 402                if (power_zone->ops->release)
 403                        power_zone->ops->release(power_zone);
 404                if (allocated)
 405                        kfree(power_zone);
 406        } else {
 407                struct powercap_control_type *control_type =
 408                                                to_powercap_control_type(dev);
 409
 410                /* Store flag as the release() may free memory */
 411                allocated = control_type->allocated;
 412                idr_destroy(&control_type->idr);
 413                mutex_destroy(&control_type->lock);
 414                if (control_type->ops && control_type->ops->release)
 415                        control_type->ops->release(control_type);
 416                if (allocated)
 417                        kfree(control_type);
 418        }
 419}
 420
 421static ssize_t enabled_show(struct device *dev,
 422                                struct device_attribute *attr,
 423                                char *buf)
 424{
 425        bool mode = true;
 426
 427        /* Default is enabled */
 428        if (dev->parent) {
 429                struct powercap_zone *power_zone = to_powercap_zone(dev);
 430                if (power_zone->ops->get_enable)
 431                        if (power_zone->ops->get_enable(power_zone, &mode))
 432                                mode = false;
 433        } else {
 434                struct powercap_control_type *control_type =
 435                                                to_powercap_control_type(dev);
 436                if (control_type->ops && control_type->ops->get_enable)
 437                        if (control_type->ops->get_enable(control_type, &mode))
 438                                mode = false;
 439        }
 440
 441        return sprintf(buf, "%d\n", mode);
 442}
 443
 444static ssize_t enabled_store(struct device *dev,
 445                                struct device_attribute *attr,
 446                                const char *buf,  size_t len)
 447{
 448        bool mode;
 449
 450        if (strtobool(buf, &mode))
 451                return -EINVAL;
 452        if (dev->parent) {
 453                struct powercap_zone *power_zone = to_powercap_zone(dev);
 454                if (power_zone->ops->set_enable)
 455                        if (!power_zone->ops->set_enable(power_zone, mode))
 456                                return len;
 457        } else {
 458                struct powercap_control_type *control_type =
 459                                                to_powercap_control_type(dev);
 460                if (control_type->ops && control_type->ops->set_enable)
 461                        if (!control_type->ops->set_enable(control_type, mode))
 462                                return len;
 463        }
 464
 465        return -ENOSYS;
 466}
 467
 468static DEVICE_ATTR_RW(enabled);
 469
 470static struct attribute *powercap_attrs[] = {
 471        &dev_attr_enabled.attr,
 472        NULL,
 473};
 474ATTRIBUTE_GROUPS(powercap);
 475
 476static struct class powercap_class = {
 477        .name = "powercap",
 478        .dev_release = powercap_release,
 479        .dev_groups = powercap_groups,
 480};
 481
 482struct powercap_zone *powercap_register_zone(
 483                        struct powercap_zone *power_zone,
 484                        struct powercap_control_type *control_type,
 485                        const char *name,
 486                        struct powercap_zone *parent,
 487                        const struct powercap_zone_ops *ops,
 488                        int nr_constraints,
 489                        const struct powercap_zone_constraint_ops *const_ops)
 490{
 491        int result;
 492        int nr_attrs;
 493
 494        if (!name || !control_type || !ops ||
 495                        nr_constraints > MAX_CONSTRAINTS_PER_ZONE ||
 496                        (!ops->get_energy_uj && !ops->get_power_uw) ||
 497                        !control_type_valid(control_type))
 498                return ERR_PTR(-EINVAL);
 499
 500        if (power_zone) {
 501                if (!ops->release)
 502                        return ERR_PTR(-EINVAL);
 503                memset(power_zone, 0, sizeof(*power_zone));
 504        } else {
 505                power_zone = kzalloc(sizeof(*power_zone), GFP_KERNEL);
 506                if (!power_zone)
 507                        return ERR_PTR(-ENOMEM);
 508                power_zone->allocated = true;
 509        }
 510        power_zone->ops = ops;
 511        power_zone->control_type_inst = control_type;
 512        if (!parent) {
 513                power_zone->dev.parent = &control_type->dev;
 514                power_zone->parent_idr = &control_type->idr;
 515        } else {
 516                power_zone->dev.parent = &parent->dev;
 517                power_zone->parent_idr = &parent->idr;
 518        }
 519        power_zone->dev.class = &powercap_class;
 520
 521        mutex_lock(&control_type->lock);
 522        /* Using idr to get the unique id */
 523        result = idr_alloc(power_zone->parent_idr, NULL, 0, 0, GFP_KERNEL);
 524        if (result < 0)
 525                goto err_idr_alloc;
 526
 527        power_zone->id = result;
 528        idr_init(&power_zone->idr);
 529        result = -ENOMEM;
 530        power_zone->name = kstrdup(name, GFP_KERNEL);
 531        if (!power_zone->name)
 532                goto err_name_alloc;
 533        dev_set_name(&power_zone->dev, "%s:%x",
 534                                        dev_name(power_zone->dev.parent),
 535                                        power_zone->id);
 536        power_zone->constraints = kcalloc(nr_constraints,
 537                                          sizeof(*power_zone->constraints),
 538                                          GFP_KERNEL);
 539        if (!power_zone->constraints)
 540                goto err_const_alloc;
 541
 542        nr_attrs = nr_constraints * POWERCAP_CONSTRAINTS_ATTRS +
 543                                                POWERCAP_ZONE_MAX_ATTRS + 1;
 544        power_zone->zone_dev_attrs = kcalloc(nr_attrs, sizeof(void *),
 545                                             GFP_KERNEL);
 546        if (!power_zone->zone_dev_attrs)
 547                goto err_attr_alloc;
 548        create_power_zone_common_attributes(power_zone);
 549        result = create_constraints(power_zone, nr_constraints, const_ops);
 550        if (result)
 551                goto err_dev_ret;
 552
 553        power_zone->zone_dev_attrs[power_zone->zone_attr_count] = NULL;
 554        power_zone->dev_zone_attr_group.attrs = power_zone->zone_dev_attrs;
 555        power_zone->dev_attr_groups[0] = &power_zone->dev_zone_attr_group;
 556        power_zone->dev_attr_groups[1] = NULL;
 557        power_zone->dev.groups = power_zone->dev_attr_groups;
 558        result = device_register(&power_zone->dev);
 559        if (result)
 560                goto err_dev_ret;
 561
 562        control_type->nr_zones++;
 563        mutex_unlock(&control_type->lock);
 564
 565        return power_zone;
 566
 567err_dev_ret:
 568        kfree(power_zone->zone_dev_attrs);
 569err_attr_alloc:
 570        kfree(power_zone->constraints);
 571err_const_alloc:
 572        kfree(power_zone->name);
 573err_name_alloc:
 574        idr_remove(power_zone->parent_idr, power_zone->id);
 575err_idr_alloc:
 576        if (power_zone->allocated)
 577                kfree(power_zone);
 578        mutex_unlock(&control_type->lock);
 579
 580        return ERR_PTR(result);
 581}
 582EXPORT_SYMBOL_GPL(powercap_register_zone);
 583
 584int powercap_unregister_zone(struct powercap_control_type *control_type,
 585                                struct powercap_zone *power_zone)
 586{
 587        if (!power_zone || !control_type)
 588                return -EINVAL;
 589
 590        mutex_lock(&control_type->lock);
 591        control_type->nr_zones--;
 592        mutex_unlock(&control_type->lock);
 593
 594        device_unregister(&power_zone->dev);
 595
 596        return 0;
 597}
 598EXPORT_SYMBOL_GPL(powercap_unregister_zone);
 599
 600struct powercap_control_type *powercap_register_control_type(
 601                                struct powercap_control_type *control_type,
 602                                const char *name,
 603                                const struct powercap_control_type_ops *ops)
 604{
 605        int result;
 606
 607        if (!name)
 608                return ERR_PTR(-EINVAL);
 609        if (control_type) {
 610                if (!ops || !ops->release)
 611                        return ERR_PTR(-EINVAL);
 612                memset(control_type, 0, sizeof(*control_type));
 613        } else {
 614                control_type = kzalloc(sizeof(*control_type), GFP_KERNEL);
 615                if (!control_type)
 616                        return ERR_PTR(-ENOMEM);
 617                control_type->allocated = true;
 618        }
 619        mutex_init(&control_type->lock);
 620        control_type->ops = ops;
 621        INIT_LIST_HEAD(&control_type->node);
 622        control_type->dev.class = &powercap_class;
 623        dev_set_name(&control_type->dev, "%s", name);
 624        result = device_register(&control_type->dev);
 625        if (result) {
 626                if (control_type->allocated)
 627                        kfree(control_type);
 628                return ERR_PTR(result);
 629        }
 630        idr_init(&control_type->idr);
 631
 632        mutex_lock(&powercap_cntrl_list_lock);
 633        list_add_tail(&control_type->node, &powercap_cntrl_list);
 634        mutex_unlock(&powercap_cntrl_list_lock);
 635
 636        return control_type;
 637}
 638EXPORT_SYMBOL_GPL(powercap_register_control_type);
 639
 640int powercap_unregister_control_type(struct powercap_control_type *control_type)
 641{
 642        struct powercap_control_type *pos = NULL;
 643
 644        if (control_type->nr_zones) {
 645                dev_err(&control_type->dev, "Zones of this type still not freed\n");
 646                return -EINVAL;
 647        }
 648        mutex_lock(&powercap_cntrl_list_lock);
 649        list_for_each_entry(pos, &powercap_cntrl_list, node) {
 650                if (pos == control_type) {
 651                        list_del(&control_type->node);
 652                        mutex_unlock(&powercap_cntrl_list_lock);
 653                        device_unregister(&control_type->dev);
 654                        return 0;
 655                }
 656        }
 657        mutex_unlock(&powercap_cntrl_list_lock);
 658
 659        return -ENODEV;
 660}
 661EXPORT_SYMBOL_GPL(powercap_unregister_control_type);
 662
 663static int __init powercap_init(void)
 664{
 665        int result;
 666
 667        result = seed_constraint_attributes();
 668        if (result)
 669                return result;
 670
 671        return class_register(&powercap_class);
 672}
 673
 674fs_initcall(powercap_init);
 675
 676MODULE_DESCRIPTION("PowerCap sysfs Driver");
 677MODULE_AUTHOR("Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>");
 678MODULE_LICENSE("GPL v2");
 679