drivers/media/media-device.c

   1 /*
   2  * Media device
   3  *
   4  * Copyright (C) 2010 Nokia Corporation
   5  *
   6  * Contacts: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
   7  *           Sakari Ailus <sakari.ailus@iki.fi>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  21  */
  22
  23 #include <linux/compat.h>
  24 #include <linux/export.h>
  25 #include <linux/ioctl.h>
  26 #include <linux/media.h>
  27 #include <linux/slab.h>
  28 #include <linux/types.h>
  29
  30 #include <media/media-device.h>
  31 #include <media/media-devnode.h>
  32 #include <media/media-entity.h>
  33
  34 #ifdef CONFIG_MEDIA_CONTROLLER
  35
  36 /* -----------------------------------------------------------------------------
  37  * Userspace API
  38  */
  39
  40 static int media_device_open(struct file *filp)
  41 {
  42         return 0;
  43 }
  44
  45 static int media_device_close(struct file *filp)
  46 {
  47         return 0;
  48 }
  49
  50 static int media_device_get_info(struct media_device *dev,
  51                                  struct media_device_info __user *__info)
  52 {
  53         struct media_device_info info;
  54
  55         memset(&info, 0, sizeof(info));
  56
  57         strlcpy(info.driver, dev->dev->driver->name, sizeof(info.driver));
  58         strlcpy(info.model, dev->model, sizeof(info.model));
  59         strlcpy(info.serial, dev->serial, sizeof(info.serial));
  60         strlcpy(info.bus_info, dev->bus_info, sizeof(info.bus_info));
  61
  62         info.media_version = MEDIA_API_VERSION;
  63         info.hw_revision = dev->hw_revision;
  64         info.driver_version = dev->driver_version;
  65
  66         if (copy_to_user(__info, &info, sizeof(*__info)))
  67                 return -EFAULT;
  68         return 0;
  69 }
  70
  71 static struct media_entity *find_entity(struct media_device *mdev, u32 id)
  72 {
  73         struct media_entity *entity;
  74         int next = id & MEDIA_ENT_ID_FLAG_NEXT;
  75
  76         id &= ~MEDIA_ENT_ID_FLAG_NEXT;
  77
  78         spin_lock(&mdev->lock);
  79
  80         media_device_for_each_entity(entity, mdev) {
  81                 if (((media_entity_id(entity) == id) && !next) ||
  82                     ((media_entity_id(entity) > id) && next)) {
  83                         spin_unlock(&mdev->lock);
  84                         return entity;
  85                 }
  86         }
  87
  88         spin_unlock(&mdev->lock);
  89
  90         return NULL;
  91 }
  92
  93 static long media_device_enum_entities(struct media_device *mdev,
  94                                        struct media_entity_desc __user *uent)
  95 {
  96         struct media_entity *ent;
  97         struct media_entity_desc u_ent;
  98
  99         memset(&u_ent, 0, sizeof(u_ent));
 100         if (copy_from_user(&u_ent.id, &uent->id, sizeof(u_ent.id)))
 101                 return -EFAULT;
 102
 103         ent = find_entity(mdev, u_ent.id);
 104
 105         if (ent == NULL)
 106                 return -EINVAL;
 107
 108         u_ent.id = media_entity_id(ent);
 109         if (ent->name)
 110                 strlcpy(u_ent.name, ent->name, sizeof(u_ent.name));
 111         u_ent.type = ent->function;
 112         u_ent.revision = 0;             /* Unused */
 113         u_ent.flags = ent->flags;
 114         u_ent.group_id = 0;             /* Unused */
 115         u_ent.pads = ent->num_pads;
 116         u_ent.links = ent->num_links - ent->num_backlinks;
 117         memcpy(&u_ent.raw, &ent->info, sizeof(ent->info));
 118         if (copy_to_user(uent, &u_ent, sizeof(u_ent)))
 119                 return -EFAULT;
 120         return 0;
 121 }
 122
 123 static void media_device_kpad_to_upad(const struct media_pad *kpad,
 124                                       struct media_pad_desc *upad)
 125 {
 126         upad->entity = media_entity_id(kpad->entity);
 127         upad->index = kpad->index;
 128         upad->flags = kpad->flags;
 129 }
 130
 131 static long __media_device_enum_links(struct media_device *mdev,
 132                                       struct media_links_enum *links)
 133 {
 134         struct media_entity *entity;
 135
 136         entity = find_entity(mdev, links->entity);
 137         if (entity == NULL)
 138                 return -EINVAL;
 139
 140         if (links->pads) {
 141                 unsigned int p;
 142
 143                 for (p = 0; p < entity->num_pads; p++) {
 144                         struct media_pad_desc pad;
 145
 146                         memset(&pad, 0, sizeof(pad));
 147                         media_device_kpad_to_upad(&entity->pads[p], &pad);
 148                         if (copy_to_user(&links->pads[p], &pad, sizeof(pad)))
 149                                 return -EFAULT;
 150                 }
 151         }
 152
 153         if (links->links) {
 154                 struct media_link *link;
 155                 struct media_link_desc __user *ulink_desc = links->links;
 156
 157                 list_for_each_entry(link, &entity->links, list) {
 158                         struct media_link_desc klink_desc;
 159
 160                         /* Ignore backlinks. */
 161                         if (link->source->entity != entity)
 162                                 continue;
 163                         memset(&klink_desc, 0, sizeof(klink_desc));
 164                         media_device_kpad_to_upad(link->source,
 165                                                   &klink_desc.source);
 166                         media_device_kpad_to_upad(link->sink,
 167                                                   &klink_desc.sink);
 168                         klink_desc.flags = link->flags;
 169                         if (copy_to_user(ulink_desc, &klink_desc,
 170                                          sizeof(*ulink_desc)))
 171                                 return -EFAULT;
 172                         ulink_desc++;
 173                 }
 174         }
 175
 176         return 0;
 177 }
 178
 179 static long media_device_enum_links(struct media_device *mdev,
 180                                     struct media_links_enum __user *ulinks)
 181 {
 182         struct media_links_enum links;
 183         int rval;
 184
 185         if (copy_from_user(&links, ulinks, sizeof(links)))
 186                 return -EFAULT;
 187
 188         rval = __media_device_enum_links(mdev, &links);
 189         if (rval < 0)
 190                 return rval;
 191
 192         if (copy_to_user(ulinks, &links, sizeof(*ulinks)))
 193                 return -EFAULT;
 194
 195         return 0;
 196 }
 197
 198 static long media_device_setup_link(struct media_device *mdev,
 199                                     struct media_link_desc __user *_ulink)
 200 {
 201         struct media_link *link = NULL;
 202         struct media_link_desc ulink;
 203         struct media_entity *source;
 204         struct media_entity *sink;
 205         int ret;
 206
 207         if (copy_from_user(&ulink, _ulink, sizeof(ulink)))
 208                 return -EFAULT;
 209
 210         /* Find the source and sink entities and link.
 211          */
 212         source = find_entity(mdev, ulink.source.entity);
 213         sink = find_entity(mdev, ulink.sink.entity);
 214
 215         if (source == NULL || sink == NULL)
 216                 return -EINVAL;
 217
 218         if (ulink.source.index >= source->num_pads ||
 219             ulink.sink.index >= sink->num_pads)
 220                 return -EINVAL;
 221
 222         link = media_entity_find_link(&source->pads[ulink.source.index],
 223                                       &sink->pads[ulink.sink.index]);
 224         if (link == NULL)
 225                 return -EINVAL;
 226
 227         /* Setup the link on both entities. */
 228         ret = __media_entity_setup_link(link, ulink.flags);
 229
 230         if (copy_to_user(_ulink, &ulink, sizeof(ulink)))
 231                 return -EFAULT;
 232
 233         return ret;
 234 }
 235
 236 static long __media_device_get_topology(struct media_device *mdev,
 237                                       struct media_v2_topology *topo)
 238 {
 239         struct media_entity *entity;
 240         struct media_interface *intf;
 241         struct media_pad *pad;
 242         struct media_link *link;
 243         struct media_v2_entity kentity, *uentity;
 244         struct media_v2_interface kintf, *uintf;
 245         struct media_v2_pad kpad, *upad;
 246         struct media_v2_link klink, *ulink;
 247         unsigned int i;
 248         int ret = 0;
 249
 250         topo->topology_version = mdev->topology_version;
 251
 252         /* Get entities and number of entities */
 253         i = 0;
 254         uentity = media_get_uptr(topo->ptr_entities);
 255         media_device_for_each_entity(entity, mdev) {
 256                 i++;
 257                 if (ret || !uentity)
 258                         continue;
 259
 260                 if (i > topo->num_entities) {
 261                         ret = -ENOSPC;
 262                         continue;
 263                 }
 264
 265                 /* Copy fields to userspace struct if not error */
 266                 memset(&kentity, 0, sizeof(kentity));
 267                 kentity.id = entity->graph_obj.id;
 268                 kentity.function = entity->function;
 269                 strncpy(kentity.name, entity->name,
 270                         sizeof(kentity.name));
 271
 272                 if (copy_to_user(uentity, &kentity, sizeof(kentity)))
 273                         ret = -EFAULT;
 274                 uentity++;
 275         }
 276         topo->num_entities = i;
 277
 278         /* Get interfaces and number of interfaces */
 279         i = 0;
 280         uintf = media_get_uptr(topo->ptr_interfaces);
 281         media_device_for_each_intf(intf, mdev) {
 282                 i++;
 283                 if (ret || !uintf)
 284                         continue;
 285
 286                 if (i > topo->num_interfaces) {
 287                         ret = -ENOSPC;
 288                         continue;
 289                 }
 290
 291                 memset(&kintf, 0, sizeof(kintf));
 292
 293                 /* Copy intf fields to userspace struct */
 294                 kintf.id = intf->graph_obj.id;
 295                 kintf.intf_type = intf->type;
 296                 kintf.flags = intf->flags;
 297
 298                 if (media_type(&intf->graph_obj) == MEDIA_GRAPH_INTF_DEVNODE) {
 299                         struct media_intf_devnode *devnode;
 300
 301                         devnode = intf_to_devnode(intf);
 302
 303                         kintf.devnode.major = devnode->major;
 304                         kintf.devnode.minor = devnode->minor;
 305                 }
 306
 307                 if (copy_to_user(uintf, &kintf, sizeof(kintf)))
 308                         ret = -EFAULT;
 309                 uintf++;
 310         }
 311         topo->num_interfaces = i;
 312
 313         /* Get pads and number of pads */
 314         i = 0;
 315         upad = media_get_uptr(topo->ptr_pads);
 316         media_device_for_each_pad(pad, mdev) {
 317                 i++;
 318                 if (ret || !upad)
 319                         continue;
 320
 321                 if (i > topo->num_pads) {
 322                         ret = -ENOSPC;
 323                         continue;
 324                 }
 325
 326                 memset(&kpad, 0, sizeof(kpad));
 327
 328                 /* Copy pad fields to userspace struct */
 329                 kpad.id = pad->graph_obj.id;
 330                 kpad.entity_id = pad->entity->graph_obj.id;
 331                 kpad.flags = pad->flags;
 332
 333                 if (copy_to_user(upad, &kpad, sizeof(kpad)))
 334                         ret = -EFAULT;
 335                 upad++;
 336         }
 337         topo->num_pads = i;
 338
 339         /* Get links and number of links */
 340         i = 0;
 341         ulink = media_get_uptr(topo->ptr_links);
 342         media_device_for_each_link(link, mdev) {
 343                 if (link->is_backlink)
 344                         continue;
 345
 346                 i++;
 347
 348                 if (ret || !ulink)
 349                         continue;
 350
 351                 if (i > topo->num_links) {
 352                         ret = -ENOSPC;
 353                         continue;
 354                 }
 355
 356                 memset(&klink, 0, sizeof(klink));
 357
 358                 /* Copy link fields to userspace struct */
 359                 klink.id = link->graph_obj.id;
 360                 klink.source_id = link->gobj0->id;
 361                 klink.sink_id = link->gobj1->id;
 362                 klink.flags = link->flags;
 363
 364                 if (copy_to_user(ulink, &klink, sizeof(klink)))
 365                         ret = -EFAULT;
 366                 ulink++;
 367         }
 368         topo->num_links = i;
 369
 370         return ret;
 371 }
 372
 373 static long media_device_get_topology(struct media_device *mdev,
 374                                       struct media_v2_topology __user *utopo)
 375 {
 376         struct media_v2_topology ktopo;
 377         int ret;
 378
 379         ret = copy_from_user(&ktopo, utopo, sizeof(ktopo));
 380
 381         if (ret < 0)
 382                 return ret;
 383
 384         ret = __media_device_get_topology(mdev, &ktopo);
 385         if (ret < 0)
 386                 return ret;
 387
 388         ret = copy_to_user(utopo, &ktopo, sizeof(*utopo));
 389
 390         return ret;
 391 }
 392
 393 static long media_device_ioctl(struct file *filp, unsigned int cmd,
 394                                unsigned long arg)
 395 {
 396         struct media_devnode *devnode = media_devnode_data(filp);
 397         struct media_device *dev = to_media_device(devnode);
 398         long ret;
 399
 400         switch (cmd) {
 401         case MEDIA_IOC_DEVICE_INFO:
 402                 ret = media_device_get_info(dev,
 403                                 (struct media_device_info __user *)arg);
 404                 break;
 405
 406         case MEDIA_IOC_ENUM_ENTITIES:
 407                 ret = media_device_enum_entities(dev,
 408                                 (struct media_entity_desc __user *)arg);
 409                 break;
 410
 411         case MEDIA_IOC_ENUM_LINKS:
 412                 mutex_lock(&dev->graph_mutex);
 413                 ret = media_device_enum_links(dev,
 414                                 (struct media_links_enum __user *)arg);
 415                 mutex_unlock(&dev->graph_mutex);
 416                 break;
 417
 418         case MEDIA_IOC_SETUP_LINK:
 419                 mutex_lock(&dev->graph_mutex);
 420                 ret = media_device_setup_link(dev,
 421                                 (struct media_link_desc __user *)arg);
 422                 mutex_unlock(&dev->graph_mutex);
 423                 break;
 424
 425         case MEDIA_IOC_G_TOPOLOGY:
 426                 mutex_lock(&dev->graph_mutex);
 427                 ret = media_device_get_topology(dev,
 428                                 (struct media_v2_topology __user *)arg);
 429                 mutex_unlock(&dev->graph_mutex);
 430                 break;
 431
 432         default:
 433                 ret = -ENOIOCTLCMD;
 434         }
 435
 436         return ret;
 437 }
 438
 439 #ifdef CONFIG_COMPAT
 440
 441 struct media_links_enum32 {
 442         __u32 entity;
 443         compat_uptr_t pads; /* struct media_pad_desc * */
 444         compat_uptr_t links; /* struct media_link_desc * */
 445         __u32 reserved[4];
 446 };
 447
 448 static long media_device_enum_links32(struct media_device *mdev,
 449                                       struct media_links_enum32 __user *ulinks)
 450 {
 451         struct media_links_enum links;
 452         compat_uptr_t pads_ptr, links_ptr;
 453
 454         memset(&links, 0, sizeof(links));
 455
 456         if (get_user(links.entity, &ulinks->entity)
 457             || get_user(pads_ptr, &ulinks->pads)
 458             || get_user(links_ptr, &ulinks->links))
 459                 return -EFAULT;
 460
 461         links.pads = compat_ptr(pads_ptr);
 462         links.links = compat_ptr(links_ptr);
 463
 464         return __media_device_enum_links(mdev, &links);
 465 }
 466
 467 #define MEDIA_IOC_ENUM_LINKS32          _IOWR('|', 0x02, struct media_links_enum32)
 468
 469 static long media_device_compat_ioctl(struct file *filp, unsigned int cmd,
 470                                       unsigned long arg)
 471 {
 472         struct media_devnode *devnode = media_devnode_data(filp);
 473         struct media_device *dev = to_media_device(devnode);
 474         long ret;
 475
 476         switch (cmd) {
 477         case MEDIA_IOC_DEVICE_INFO:
 478         case MEDIA_IOC_ENUM_ENTITIES:
 479         case MEDIA_IOC_SETUP_LINK:
 480         case MEDIA_IOC_G_TOPOLOGY:
 481                 return media_device_ioctl(filp, cmd, arg);
 482
 483         case MEDIA_IOC_ENUM_LINKS32:
 484                 mutex_lock(&dev->graph_mutex);
 485                 ret = media_device_enum_links32(dev,
 486                                 (struct media_links_enum32 __user *)arg);
 487                 mutex_unlock(&dev->graph_mutex);
 488                 break;
 489
 490         default:
 491                 ret = -ENOIOCTLCMD;
 492         }
 493
 494         return ret;
 495 }
 496 #endif /* CONFIG_COMPAT */
 497
 498 static const struct media_file_operations media_device_fops = {
 499         .owner = THIS_MODULE,
 500         .open = media_device_open,
 501         .ioctl = media_device_ioctl,
 502 #ifdef CONFIG_COMPAT
 503         .compat_ioctl = media_device_compat_ioctl,
 504 #endif /* CONFIG_COMPAT */
 505         .release = media_device_close,
 506 };
 507
 508 /* -----------------------------------------------------------------------------
 509  * sysfs
 510  */
 511
 512 static ssize_t show_model(struct device *cd,
 513                           struct device_attribute *attr, char *buf)
 514 {
 515         struct media_device *mdev = to_media_device(to_media_devnode(cd));
 516
 517         return sprintf(buf, "%.*s\n", (int)sizeof(mdev->model), mdev->model);
 518 }
 519
 520 static DEVICE_ATTR(model, S_IRUGO, show_model, NULL);
 521
 522 /* -----------------------------------------------------------------------------
 523  * Registration/unregistration
 524  */
 525
 526 static void media_device_release(struct media_devnode *mdev)
 527 {
 528         dev_dbg(mdev->parent, "Media device released\n");
 529 }
 530
 531 /**
 532  * media_device_register_entity - Register an entity with a media device
 533  * @mdev:       The media device
 534  * @entity:     The entity
 535  */
 536 int __must_check media_device_register_entity(struct media_device *mdev,
 537                                               struct media_entity *entity)
 538 {
 539         unsigned int i;
 540
 541         if (entity->function == MEDIA_ENT_F_V4L2_SUBDEV_UNKNOWN ||
 542             entity->function == MEDIA_ENT_F_UNKNOWN)
 543                 dev_warn(mdev->dev,
 544                          "Entity type for entity %s was not initialized!\n",
 545                          entity->name);
 546
 547         /* Warn if we apparently re-register an entity */
 548         WARN_ON(entity->graph_obj.mdev != NULL);
 549         entity->graph_obj.mdev = mdev;
 550         INIT_LIST_HEAD(&entity->links);
 551         entity->num_links = 0;
 552         entity->num_backlinks = 0;
 553
 554         spin_lock(&mdev->lock);
 555         /* Initialize media_gobj embedded at the entity */
 556         media_gobj_create(mdev, MEDIA_GRAPH_ENTITY, &entity->graph_obj);
 557
 558         /* Initialize objects at the pads */
 559         for (i = 0; i < entity->num_pads; i++)
 560                 media_gobj_create(mdev, MEDIA_GRAPH_PAD,
 561                                &entity->pads[i].graph_obj);
 562
 563         spin_unlock(&mdev->lock);
 564
 565         return 0;
 566 }
 567 EXPORT_SYMBOL_GPL(media_device_register_entity);
 568
 569 /**
 570  * media_device_unregister_entity - Unregister an entity
 571  * @entity:     The entity
 572  *
 573  * If the entity has never been registered this function will return
 574  * immediately.
 575  */
 576 void media_device_unregister_entity(struct media_entity *entity)
 577 {
 578         struct media_device *mdev = entity->graph_obj.mdev;
 579         struct media_link *link, *tmp;
 580         struct media_interface *intf;
 581         unsigned int i;
 582
 583         if (mdev == NULL)
 584                 return;
 585
 586         spin_lock(&mdev->lock);
 587
 588         /* Remove all interface links pointing to this entity */
 589         list_for_each_entry(intf, &mdev->interfaces, graph_obj.list) {
 590                 list_for_each_entry_safe(link, tmp, &intf->links, list) {
 591                         if (link->entity == entity)
 592                                 __media_remove_intf_link(link);
 593                 }
 594         }
 595
 596         /* Remove all data links that belong to this entity */
 597         __media_entity_remove_links(entity);
 598
 599         /* Remove all pads that belong to this entity */
 600         for (i = 0; i < entity->num_pads; i++)
 601                 media_gobj_destroy(&entity->pads[i].graph_obj);
 602
 603         /* Remove the entity */
 604         media_gobj_destroy(&entity->graph_obj);
 605
 606         spin_unlock(&mdev->lock);
 607         entity->graph_obj.mdev = NULL;
 608 }
 609 EXPORT_SYMBOL_GPL(media_device_unregister_entity);
 610
 611 /**
 612  * media_device_register - register a media device
 613  * @mdev:       The media device
 614  *
 615  * The caller is responsible for initializing the media device before
 616  * registration. The following fields must be set:
 617  *
 618  * - dev must point to the parent device
 619  * - model must be filled with the device model name
 620  */
 621 int __must_check __media_device_register(struct media_device *mdev,
 622                                          struct module *owner)
 623 {
 624         int ret;
 625
 626         if (WARN_ON(mdev->dev == NULL || mdev->model[0] == 0))
 627                 return -EINVAL;
 628
 629         INIT_LIST_HEAD(&mdev->entities);
 630         INIT_LIST_HEAD(&mdev->interfaces);
 631         INIT_LIST_HEAD(&mdev->pads);
 632         INIT_LIST_HEAD(&mdev->links);
 633         spin_lock_init(&mdev->lock);
 634         mutex_init(&mdev->graph_mutex);
 635
 636         /* Register the device node. */
 637         mdev->devnode.fops = &media_device_fops;
 638         mdev->devnode.parent = mdev->dev;
 639         mdev->devnode.release = media_device_release;
 640         ret = media_devnode_register(&mdev->devnode, owner);
 641         if (ret < 0)
 642                 return ret;
 643
 644         ret = device_create_file(&mdev->devnode.dev, &dev_attr_model);
 645         if (ret < 0) {
 646                 media_devnode_unregister(&mdev->devnode);
 647                 return ret;
 648         }
 649
 650         dev_dbg(mdev->dev, "Media device registered\n");
 651
 652         return 0;
 653 }
 654 EXPORT_SYMBOL_GPL(__media_device_register);
 655
 656 /**
 657  * media_device_unregister - unregister a media device
 658  * @mdev:       The media device
 659  *
 660  * It is safe to call this function on an unregistered
 661  * (but initialised) media device.
 662  */
 663 void media_device_unregister(struct media_device *mdev)
 664 {
 665         struct media_entity *entity;
 666         struct media_entity *next;
 667         struct media_interface *intf, *tmp_intf;
 668
 669         /* Check if mdev was ever registered at all */
 670         if (!media_devnode_is_registered(&mdev->devnode))
 671                 return;
 672
 673         /* Remove all entities from the media device */
 674         list_for_each_entry_safe(entity, next, &mdev->entities, graph_obj.list)
 675                 media_device_unregister_entity(entity);
 676
 677         /* Remove all interfaces from the media device */
 678         spin_lock(&mdev->lock);
 679         list_for_each_entry_safe(intf, tmp_intf, &mdev->interfaces,
 680                                  graph_obj.list) {
 681                 __media_remove_intf_links(intf);
 682                 media_gobj_destroy(&intf->graph_obj);
 683                 kfree(intf);
 684         }
 685         spin_unlock(&mdev->lock);
 686
 687         device_remove_file(&mdev->devnode.dev, &dev_attr_model);
 688         media_devnode_unregister(&mdev->devnode);
 689
 690         dev_dbg(mdev->dev, "Media device unregistered\n");
 691 }
 692 EXPORT_SYMBOL_GPL(media_device_unregister);
 693
 694 static void media_device_release_devres(struct device *dev, void *res)
 695 {
 696 }
 697
 698 struct media_device *media_device_get_devres(struct device *dev)
 699 {
 700         struct media_device *mdev;
 701
 702         mdev = devres_find(dev, media_device_release_devres, NULL, NULL);
 703         if (mdev)
 704                 return mdev;
 705
 706         mdev = devres_alloc(media_device_release_devres,
 707                                 sizeof(struct media_device), GFP_KERNEL);
 708         if (!mdev)
 709                 return NULL;
 710         return devres_get(dev, mdev, NULL, NULL);
 711 }
 712 EXPORT_SYMBOL_GPL(media_device_get_devres);
 713
 714 struct media_device *media_device_find_devres(struct device *dev)
 715 {
 716         return devres_find(dev, media_device_release_devres, NULL, NULL);
 717 }
 718 EXPORT_SYMBOL_GPL(media_device_find_devres);
 719
 720 #endif /* CONFIG_MEDIA_CONTROLLER */