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/types.h>
  28 #include <linux/slab.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 = ent->revision;
 113         u_ent.flags = ent->flags;
 114         u_ent.group_id = ent->group_id;
 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 *ent_link;
 155                 struct media_link_desc __user *ulink = links->links;
 156
 157                 list_for_each_entry(ent_link, &entity->links, list) {
 158                         struct media_link_desc link;
 159
 160                         /* Ignore backlinks. */
 161                         if (ent_link->source->entity != entity)
 162                                 continue;
 163                         memset(&link, 0, sizeof(link));
 164                         media_device_kpad_to_upad(ent_link->source,
 165                                                   &link.source);
 166                         media_device_kpad_to_upad(ent_link->sink,
 167                                                   &link.sink);
 168                         link.flags = ent_link->flags;
 169                         if (copy_to_user(ulink, &link, sizeof(*ulink)))
 170                                 return -EFAULT;
 171                         ulink++;
 172                 }
 173         }
 174
 175         return 0;
 176 }
 177
 178 static long media_device_enum_links(struct media_device *mdev,
 179                                     struct media_links_enum __user *ulinks)
 180 {
 181         struct media_links_enum links;
 182         int rval;
 183
 184         if (copy_from_user(&links, ulinks, sizeof(links)))
 185                 return -EFAULT;
 186
 187         rval = __media_device_enum_links(mdev, &links);
 188         if (rval < 0)
 189                 return rval;
 190
 191         if (copy_to_user(ulinks, &links, sizeof(*ulinks)))
 192                 return -EFAULT;
 193
 194         return 0;
 195 }
 196
 197 static long media_device_setup_link(struct media_device *mdev,
 198                                     struct media_link_desc __user *_ulink)
 199 {
 200         struct media_link *link = NULL;
 201         struct media_link_desc ulink;
 202         struct media_entity *source;
 203         struct media_entity *sink;
 204         int ret;
 205
 206         if (copy_from_user(&ulink, _ulink, sizeof(ulink)))
 207                 return -EFAULT;
 208
 209         /* Find the source and sink entities and link.
 210          */
 211         source = find_entity(mdev, ulink.source.entity);
 212         sink = find_entity(mdev, ulink.sink.entity);
 213
 214         if (source == NULL || sink == NULL)
 215                 return -EINVAL;
 216
 217         if (ulink.source.index >= source->num_pads ||
 218             ulink.sink.index >= sink->num_pads)
 219                 return -EINVAL;
 220
 221         link = media_entity_find_link(&source->pads[ulink.source.index],
 222                                       &sink->pads[ulink.sink.index]);
 223         if (link == NULL)
 224                 return -EINVAL;
 225
 226         /* Setup the link on both entities. */
 227         ret = __media_entity_setup_link(link, ulink.flags);
 228
 229         if (copy_to_user(_ulink, &ulink, sizeof(ulink)))
 230                 return -EFAULT;
 231
 232         return ret;
 233 }
 234
 235 static long __media_device_get_topology(struct media_device *mdev,
 236                                       struct media_v2_topology *topo)
 237 {
 238         struct media_entity *entity;
 239         struct media_interface *intf;
 240         struct media_pad *pad;
 241         struct media_link *link;
 242         struct media_v2_entity uentity;
 243         struct media_v2_interface uintf;
 244         struct media_v2_pad upad;
 245         struct media_v2_link ulink;
 246         int ret = 0, i;
 247
 248         topo->topology_version = mdev->topology_version;
 249
 250         /* Get entities and number of entities */
 251         i = 0;
 252         media_device_for_each_entity(entity, mdev) {
 253                 i++;
 254
 255                 if (ret || !topo->entities)
 256                         continue;
 257
 258                 if (i > topo->num_entities) {
 259                         ret = -ENOSPC;
 260                         continue;
 261                 }
 262
 263                 /* Copy fields to userspace struct if not error */
 264                 memset(&uentity, 0, sizeof(uentity));
 265                 uentity.id = entity->graph_obj.id;
 266                 strncpy(uentity.name, entity->name,
 267                         sizeof(uentity.name));
 268
 269                 if (copy_to_user(&topo->entities[i - 1], &uentity, sizeof(uentity)))
 270                         ret = -EFAULT;
 271         }
 272         topo->num_entities = i;
 273
 274         /* Get interfaces and number of interfaces */
 275         i = 0;
 276         media_device_for_each_intf(intf, mdev) {
 277                 i++;
 278
 279                 if (ret || !topo->interfaces)
 280                         continue;
 281
 282                 if (i > topo->num_interfaces) {
 283                         ret = -ENOSPC;
 284                         continue;
 285                 }
 286
 287                 memset(&uintf, 0, sizeof(uintf));
 288
 289                 /* Copy intf fields to userspace struct */
 290                 uintf.id = intf->graph_obj.id;
 291                 uintf.intf_type = intf->type;
 292                 uintf.flags = intf->flags;
 293
 294                 if (media_type(&intf->graph_obj) == MEDIA_GRAPH_INTF_DEVNODE) {
 295                         struct media_intf_devnode *devnode;
 296
 297                         devnode = intf_to_devnode(intf);
 298
 299                         uintf.devnode.major = devnode->major;
 300                         uintf.devnode.minor = devnode->minor;
 301                 }
 302
 303                 if (copy_to_user(&topo->interfaces[i - 1], &uintf, sizeof(uintf)))
 304                         ret = -EFAULT;
 305         }
 306         topo->num_interfaces = i;
 307
 308         /* Get pads and number of pads */
 309         i = 0;
 310         media_device_for_each_pad(pad, mdev) {
 311                 i++;
 312
 313                 if (ret || !topo->pads)
 314                         continue;
 315
 316                 if (i > topo->num_pads) {
 317                         ret = -ENOSPC;
 318                         continue;
 319                 }
 320
 321                 memset(&upad, 0, sizeof(upad));
 322
 323                 /* Copy pad fields to userspace struct */
 324                 upad.id = pad->graph_obj.id;
 325                 upad.entity_id = pad->entity->graph_obj.id;
 326                 upad.flags = pad->flags;
 327
 328                 if (copy_to_user(&topo->pads[i - 1], &upad, sizeof(upad)))
 329                         ret = -EFAULT;
 330         }
 331         topo->num_pads = i;
 332
 333         /* Get links and number of links */
 334         i = 0;
 335         media_device_for_each_link(link, mdev) {
 336                 if (link->is_backlink)
 337                         continue;
 338
 339                 i++;
 340
 341                 if (ret || !topo->links)
 342                         continue;
 343
 344                 if (i > topo->num_links) {
 345                         ret = -ENOSPC;
 346                         continue;
 347                 }
 348
 349                 memset(&ulink, 0, sizeof(ulink));
 350
 351                 /* Copy link fields to userspace struct */
 352                 ulink.id = link->graph_obj.id;
 353                 ulink.source_id = link->gobj0->id;
 354                 ulink.sink_id = link->gobj1->id;
 355                 ulink.flags = link->flags;
 356
 357                 if (media_type(link->gobj0) != MEDIA_GRAPH_PAD)
 358                         ulink.flags |= MEDIA_LNK_FL_INTERFACE_LINK;
 359
 360                 if (copy_to_user(&topo->links[i - 1], &ulink, sizeof(ulink)))
 361                         ret = -EFAULT;
 362         }
 363         topo->num_links = i;
 364
 365         return ret;
 366 }
 367
 368 static long media_device_get_topology(struct media_device *mdev,
 369                                       struct media_v2_topology __user *utopo)
 370 {
 371         struct media_v2_topology ktopo;
 372         int ret;
 373
 374         ret = copy_from_user(&ktopo, utopo, sizeof(ktopo));
 375
 376         if (ret < 0)
 377                 return ret;
 378
 379         ret = __media_device_get_topology(mdev, &ktopo);
 380         if (ret < 0)
 381                 return ret;
 382
 383         ret = copy_to_user(utopo, &ktopo, sizeof(*utopo));
 384
 385         return ret;
 386 }
 387
 388 static long media_device_ioctl(struct file *filp, unsigned int cmd,
 389                                unsigned long arg)
 390 {
 391         struct media_devnode *devnode = media_devnode_data(filp);
 392         struct media_device *dev = to_media_device(devnode);
 393         long ret;
 394
 395         switch (cmd) {
 396         case MEDIA_IOC_DEVICE_INFO:
 397                 ret = media_device_get_info(dev,
 398                                 (struct media_device_info __user *)arg);
 399                 break;
 400
 401         case MEDIA_IOC_ENUM_ENTITIES:
 402                 ret = media_device_enum_entities(dev,
 403                                 (struct media_entity_desc __user *)arg);
 404                 break;
 405
 406         case MEDIA_IOC_ENUM_LINKS:
 407                 mutex_lock(&dev->graph_mutex);
 408                 ret = media_device_enum_links(dev,
 409                                 (struct media_links_enum __user *)arg);
 410                 mutex_unlock(&dev->graph_mutex);
 411                 break;
 412
 413         case MEDIA_IOC_SETUP_LINK:
 414                 mutex_lock(&dev->graph_mutex);
 415                 ret = media_device_setup_link(dev,
 416                                 (struct media_link_desc __user *)arg);
 417                 mutex_unlock(&dev->graph_mutex);
 418                 break;
 419
 420         case MEDIA_IOC_G_TOPOLOGY:
 421                 mutex_lock(&dev->graph_mutex);
 422                 ret = media_device_get_topology(dev,
 423                                 (struct media_v2_topology __user *)arg);
 424                 mutex_unlock(&dev->graph_mutex);
 425                 break;
 426
 427         default:
 428                 ret = -ENOIOCTLCMD;
 429         }
 430
 431         return ret;
 432 }
 433
 434 #ifdef CONFIG_COMPAT
 435
 436 struct media_links_enum32 {
 437         __u32 entity;
 438         compat_uptr_t pads; /* struct media_pad_desc * */
 439         compat_uptr_t links; /* struct media_link_desc * */
 440         __u32 reserved[4];
 441 };
 442
 443 static long media_device_enum_links32(struct media_device *mdev,
 444                                       struct media_links_enum32 __user *ulinks)
 445 {
 446         struct media_links_enum links;
 447         compat_uptr_t pads_ptr, links_ptr;
 448
 449         memset(&links, 0, sizeof(links));
 450
 451         if (get_user(links.entity, &ulinks->entity)
 452             || get_user(pads_ptr, &ulinks->pads)
 453             || get_user(links_ptr, &ulinks->links))
 454                 return -EFAULT;
 455
 456         links.pads = compat_ptr(pads_ptr);
 457         links.links = compat_ptr(links_ptr);
 458
 459         return __media_device_enum_links(mdev, &links);
 460 }
 461
 462 #define MEDIA_IOC_ENUM_LINKS32          _IOWR('|', 0x02, struct media_links_enum32)
 463
 464 static long media_device_compat_ioctl(struct file *filp, unsigned int cmd,
 465                                       unsigned long arg)
 466 {
 467         struct media_devnode *devnode = media_devnode_data(filp);
 468         struct media_device *dev = to_media_device(devnode);
 469         long ret;
 470
 471         switch (cmd) {
 472         case MEDIA_IOC_DEVICE_INFO:
 473         case MEDIA_IOC_ENUM_ENTITIES:
 474         case MEDIA_IOC_SETUP_LINK:
 475         case MEDIA_IOC_G_TOPOLOGY:
 476                 return media_device_ioctl(filp, cmd, arg);
 477
 478         case MEDIA_IOC_ENUM_LINKS32:
 479                 mutex_lock(&dev->graph_mutex);
 480                 ret = media_device_enum_links32(dev,
 481                                 (struct media_links_enum32 __user *)arg);
 482                 mutex_unlock(&dev->graph_mutex);
 483                 break;
 484
 485         default:
 486                 ret = -ENOIOCTLCMD;
 487         }
 488
 489         return ret;
 490 }
 491 #endif /* CONFIG_COMPAT */
 492
 493 static const struct media_file_operations media_device_fops = {
 494         .owner = THIS_MODULE,
 495         .open = media_device_open,
 496         .ioctl = media_device_ioctl,
 497 #ifdef CONFIG_COMPAT
 498         .compat_ioctl = media_device_compat_ioctl,
 499 #endif /* CONFIG_COMPAT */
 500         .release = media_device_close,
 501 };
 502
 503 /* -----------------------------------------------------------------------------
 504  * sysfs
 505  */
 506
 507 static ssize_t show_model(struct device *cd,
 508                           struct device_attribute *attr, char *buf)
 509 {
 510         struct media_device *mdev = to_media_device(to_media_devnode(cd));
 511
 512         return sprintf(buf, "%.*s\n", (int)sizeof(mdev->model), mdev->model);
 513 }
 514
 515 static DEVICE_ATTR(model, S_IRUGO, show_model, NULL);
 516
 517 /* -----------------------------------------------------------------------------
 518  * Registration/unregistration
 519  */
 520
 521 static void media_device_release(struct media_devnode *mdev)
 522 {
 523         dev_dbg(mdev->parent, "Media device released\n");
 524 }
 525
 526 /**
 527  * media_device_register - register a media device
 528  * @mdev:       The media device
 529  *
 530  * The caller is responsible for initializing the media device before
 531  * registration. The following fields must be set:
 532  *
 533  * - dev must point to the parent device
 534  * - model must be filled with the device model name
 535  */
 536 int __must_check __media_device_register(struct media_device *mdev,
 537                                          struct module *owner)
 538 {
 539         int ret;
 540
 541         if (WARN_ON(mdev->dev == NULL || mdev->model[0] == 0))
 542                 return -EINVAL;
 543
 544         INIT_LIST_HEAD(&mdev->entities);
 545         INIT_LIST_HEAD(&mdev->interfaces);
 546         INIT_LIST_HEAD(&mdev->pads);
 547         INIT_LIST_HEAD(&mdev->links);
 548         spin_lock_init(&mdev->lock);
 549         mutex_init(&mdev->graph_mutex);
 550
 551         /* Register the device node. */
 552         mdev->devnode.fops = &media_device_fops;
 553         mdev->devnode.parent = mdev->dev;
 554         mdev->devnode.release = media_device_release;
 555         ret = media_devnode_register(&mdev->devnode, owner);
 556         if (ret < 0)
 557                 return ret;
 558
 559         ret = device_create_file(&mdev->devnode.dev, &dev_attr_model);
 560         if (ret < 0) {
 561                 media_devnode_unregister(&mdev->devnode);
 562                 return ret;
 563         }
 564
 565         dev_dbg(mdev->dev, "Media device registered\n");
 566
 567         return 0;
 568 }
 569 EXPORT_SYMBOL_GPL(__media_device_register);
 570
 571 /**
 572  * media_device_unregister - unregister a media device
 573  * @mdev:       The media device
 574  *
 575  */
 576 void media_device_unregister(struct media_device *mdev)
 577 {
 578         struct media_entity *entity;
 579         struct media_entity *next;
 580         struct media_interface *intf, *tmp_intf;
 581
 582         /* Remove all entities from the media device */
 583         list_for_each_entry_safe(entity, next, &mdev->entities, graph_obj.list)
 584                 media_device_unregister_entity(entity);
 585
 586         /* Remove all interfaces from the media device */
 587         spin_lock(&mdev->lock);
 588         list_for_each_entry_safe(intf, tmp_intf, &mdev->interfaces,
 589                                  graph_obj.list) {
 590                 __media_remove_intf_links(intf);
 591                 media_gobj_remove(&intf->graph_obj);
 592                 kfree(intf);
 593         }
 594         spin_unlock(&mdev->lock);
 595
 596         device_remove_file(&mdev->devnode.dev, &dev_attr_model);
 597         media_devnode_unregister(&mdev->devnode);
 598
 599         dev_dbg(mdev->dev, "Media device unregistered\n");
 600 }
 601 EXPORT_SYMBOL_GPL(media_device_unregister);
 602
 603 /**
 604  * media_device_register_entity - Register an entity with a media device
 605  * @mdev:       The media device
 606  * @entity:     The entity
 607  */
 608 int __must_check media_device_register_entity(struct media_device *mdev,
 609                                               struct media_entity *entity)
 610 {
 611         int i;
 612
 613         if (entity->function == MEDIA_ENT_T_V4L2_SUBDEV_UNKNOWN ||
 614             entity->function == MEDIA_ENT_T_UNKNOWN)
 615                 dev_warn(mdev->dev,
 616                          "Entity type for entity %s was not initialized!\n",
 617                          entity->name);
 618
 619         /* Warn if we apparently re-register an entity */
 620         WARN_ON(entity->graph_obj.mdev != NULL);
 621         entity->graph_obj.mdev = mdev;
 622         INIT_LIST_HEAD(&entity->links);
 623
 624         spin_lock(&mdev->lock);
 625         /* Initialize media_gobj embedded at the entity */
 626         media_gobj_init(mdev, MEDIA_GRAPH_ENTITY, &entity->graph_obj);
 627
 628         /* Initialize objects at the pads */
 629         for (i = 0; i < entity->num_pads; i++)
 630                 media_gobj_init(mdev, MEDIA_GRAPH_PAD,
 631                                &entity->pads[i].graph_obj);
 632
 633         spin_unlock(&mdev->lock);
 634
 635         return 0;
 636 }
 637 EXPORT_SYMBOL_GPL(media_device_register_entity);
 638
 639 /**
 640  * media_device_unregister_entity - Unregister an entity
 641  * @entity:     The entity
 642  *
 643  * If the entity has never been registered this function will return
 644  * immediately.
 645  */
 646 void media_device_unregister_entity(struct media_entity *entity)
 647 {
 648         int i;
 649         struct media_device *mdev = entity->graph_obj.mdev;
 650         struct media_link *link, *tmp;
 651         struct media_interface *intf;
 652
 653         if (mdev == NULL)
 654                 return;
 655
 656         spin_lock(&mdev->lock);
 657
 658         /* Remove all interface links pointing to this entity */
 659         list_for_each_entry(intf, &mdev->interfaces, graph_obj.list) {
 660                 list_for_each_entry_safe(link, tmp, &intf->links, list) {
 661                         if (link->entity == entity)
 662                                 __media_remove_intf_link(link);
 663                 }
 664         }
 665
 666         /* Remove all data links that belong to this entity */
 667         __media_entity_remove_links(entity);
 668
 669         /* Remove all pads that belong to this entity */
 670         for (i = 0; i < entity->num_pads; i++)
 671                 media_gobj_remove(&entity->pads[i].graph_obj);
 672
 673         /* Remove the entity */
 674         media_gobj_remove(&entity->graph_obj);
 675
 676         spin_unlock(&mdev->lock);
 677         entity->graph_obj.mdev = NULL;
 678 }
 679 EXPORT_SYMBOL_GPL(media_device_unregister_entity);
 680
 681 static void media_device_release_devres(struct device *dev, void *res)
 682 {
 683 }
 684
 685 /*
 686  * media_device_get_devres() -  get media device as device resource
 687  *                              creates if one doesn't exist
 688 */
 689 struct media_device *media_device_get_devres(struct device *dev)
 690 {
 691         struct media_device *mdev;
 692
 693         mdev = devres_find(dev, media_device_release_devres, NULL, NULL);
 694         if (mdev)
 695                 return mdev;
 696
 697         mdev = devres_alloc(media_device_release_devres,
 698                                 sizeof(struct media_device), GFP_KERNEL);
 699         if (!mdev)
 700                 return NULL;
 701         return devres_get(dev, mdev, NULL, NULL);
 702 }
 703 EXPORT_SYMBOL_GPL(media_device_get_devres);
 704
 705 /*
 706  * media_device_find_devres() - find media device as device resource
 707 */
 708 struct media_device *media_device_find_devres(struct device *dev)
 709 {
 710         return devres_find(dev, media_device_release_devres, NULL, NULL);
 711 }
 712 EXPORT_SYMBOL_GPL(media_device_find_devres);
 713
 714 #endif /* CONFIG_MEDIA_CONTROLLER */