drivers/powercap/powercap_sys.c

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