linux/drivers/media/v4l2-core/v4l2-async.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * V4L2 asynchronous subdevice registration API
   4 *
   5 * Copyright (C) 2012-2013, Guennadi Liakhovetski <g.liakhovetski@gmx.de>
   6 */
   7
   8#include <linux/debugfs.h>
   9#include <linux/device.h>
  10#include <linux/err.h>
  11#include <linux/i2c.h>
  12#include <linux/list.h>
  13#include <linux/mm.h>
  14#include <linux/module.h>
  15#include <linux/mutex.h>
  16#include <linux/of.h>
  17#include <linux/platform_device.h>
  18#include <linux/seq_file.h>
  19#include <linux/slab.h>
  20#include <linux/types.h>
  21
  22#include <media/v4l2-async.h>
  23#include <media/v4l2-device.h>
  24#include <media/v4l2-fwnode.h>
  25#include <media/v4l2-subdev.h>
  26
  27static int v4l2_async_notifier_call_bound(struct v4l2_async_notifier *n,
  28                                          struct v4l2_subdev *subdev,
  29                                          struct v4l2_async_subdev *asd)
  30{
  31        if (!n->ops || !n->ops->bound)
  32                return 0;
  33
  34        return n->ops->bound(n, subdev, asd);
  35}
  36
  37static void v4l2_async_notifier_call_unbind(struct v4l2_async_notifier *n,
  38                                            struct v4l2_subdev *subdev,
  39                                            struct v4l2_async_subdev *asd)
  40{
  41        if (!n->ops || !n->ops->unbind)
  42                return;
  43
  44        n->ops->unbind(n, subdev, asd);
  45}
  46
  47static int v4l2_async_notifier_call_complete(struct v4l2_async_notifier *n)
  48{
  49        if (!n->ops || !n->ops->complete)
  50                return 0;
  51
  52        return n->ops->complete(n);
  53}
  54
  55static bool match_i2c(struct v4l2_async_notifier *notifier,
  56                      struct v4l2_subdev *sd, struct v4l2_async_subdev *asd)
  57{
  58#if IS_ENABLED(CONFIG_I2C)
  59        struct i2c_client *client = i2c_verify_client(sd->dev);
  60
  61        return client &&
  62                asd->match.i2c.adapter_id == client->adapter->nr &&
  63                asd->match.i2c.address == client->addr;
  64#else
  65        return false;
  66#endif
  67}
  68
  69static bool match_fwnode(struct v4l2_async_notifier *notifier,
  70                         struct v4l2_subdev *sd, struct v4l2_async_subdev *asd)
  71{
  72        struct fwnode_handle *other_fwnode;
  73        struct fwnode_handle *dev_fwnode;
  74        bool asd_fwnode_is_ep;
  75        bool sd_fwnode_is_ep;
  76        struct device *dev;
  77
  78        /*
  79         * Both the subdev and the async subdev can provide either an endpoint
  80         * fwnode or a device fwnode. Start with the simple case of direct
  81         * fwnode matching.
  82         */
  83        if (sd->fwnode == asd->match.fwnode)
  84                return true;
  85
  86        /*
  87         * Check the same situation for any possible secondary assigned to the
  88         * subdev's fwnode
  89         */
  90        if (!IS_ERR_OR_NULL(sd->fwnode->secondary) &&
  91            sd->fwnode->secondary == asd->match.fwnode)
  92                return true;
  93
  94        /*
  95         * Otherwise, check if the sd fwnode and the asd fwnode refer to an
  96         * endpoint or a device. If they're of the same type, there's no match.
  97         * Technically speaking this checks if the nodes refer to a connected
  98         * endpoint, which is the simplest check that works for both OF and
  99         * ACPI. This won't make a difference, as drivers should not try to
 100         * match unconnected endpoints.
 101         */
 102        sd_fwnode_is_ep = fwnode_graph_is_endpoint(sd->fwnode);
 103        asd_fwnode_is_ep = fwnode_graph_is_endpoint(asd->match.fwnode);
 104
 105        if (sd_fwnode_is_ep == asd_fwnode_is_ep)
 106                return false;
 107
 108        /*
 109         * The sd and asd fwnodes are of different types. Get the device fwnode
 110         * parent of the endpoint fwnode, and compare it with the other fwnode.
 111         */
 112        if (sd_fwnode_is_ep) {
 113                dev_fwnode = fwnode_graph_get_port_parent(sd->fwnode);
 114                other_fwnode = asd->match.fwnode;
 115        } else {
 116                dev_fwnode = fwnode_graph_get_port_parent(asd->match.fwnode);
 117                other_fwnode = sd->fwnode;
 118        }
 119
 120        fwnode_handle_put(dev_fwnode);
 121
 122        if (dev_fwnode != other_fwnode)
 123                return false;
 124
 125        /*
 126         * We have a heterogeneous match. Retrieve the struct device of the side
 127         * that matched on a device fwnode to print its driver name.
 128         */
 129        if (sd_fwnode_is_ep)
 130                dev = notifier->v4l2_dev ? notifier->v4l2_dev->dev
 131                    : notifier->sd->dev;
 132        else
 133                dev = sd->dev;
 134
 135        if (dev && dev->driver) {
 136                if (sd_fwnode_is_ep)
 137                        dev_warn(dev, "Driver %s uses device fwnode, incorrect match may occur\n",
 138                                 dev->driver->name);
 139                dev_notice(dev, "Consider updating driver %s to match on endpoints\n",
 140                           dev->driver->name);
 141        }
 142
 143        return true;
 144}
 145
 146static LIST_HEAD(subdev_list);
 147static LIST_HEAD(notifier_list);
 148static DEFINE_MUTEX(list_lock);
 149
 150static struct v4l2_async_subdev *
 151v4l2_async_find_match(struct v4l2_async_notifier *notifier,
 152                      struct v4l2_subdev *sd)
 153{
 154        bool (*match)(struct v4l2_async_notifier *notifier,
 155                      struct v4l2_subdev *sd, struct v4l2_async_subdev *asd);
 156        struct v4l2_async_subdev *asd;
 157
 158        list_for_each_entry(asd, &notifier->waiting, list) {
 159                /* bus_type has been verified valid before */
 160                switch (asd->match_type) {
 161                case V4L2_ASYNC_MATCH_I2C:
 162                        match = match_i2c;
 163                        break;
 164                case V4L2_ASYNC_MATCH_FWNODE:
 165                        match = match_fwnode;
 166                        break;
 167                default:
 168                        /* Cannot happen, unless someone breaks us */
 169                        WARN_ON(true);
 170                        return NULL;
 171                }
 172
 173                /* match cannot be NULL here */
 174                if (match(notifier, sd, asd))
 175                        return asd;
 176        }
 177
 178        return NULL;
 179}
 180
 181/* Compare two async sub-device descriptors for equivalence */
 182static bool asd_equal(struct v4l2_async_subdev *asd_x,
 183                      struct v4l2_async_subdev *asd_y)
 184{
 185        if (asd_x->match_type != asd_y->match_type)
 186                return false;
 187
 188        switch (asd_x->match_type) {
 189        case V4L2_ASYNC_MATCH_I2C:
 190                return asd_x->match.i2c.adapter_id ==
 191                        asd_y->match.i2c.adapter_id &&
 192                        asd_x->match.i2c.address ==
 193                        asd_y->match.i2c.address;
 194        case V4L2_ASYNC_MATCH_FWNODE:
 195                return asd_x->match.fwnode == asd_y->match.fwnode;
 196        default:
 197                break;
 198        }
 199
 200        return false;
 201}
 202
 203/* Find the sub-device notifier registered by a sub-device driver. */
 204static struct v4l2_async_notifier *
 205v4l2_async_find_subdev_notifier(struct v4l2_subdev *sd)
 206{
 207        struct v4l2_async_notifier *n;
 208
 209        list_for_each_entry(n, &notifier_list, list)
 210                if (n->sd == sd)
 211                        return n;
 212
 213        return NULL;
 214}
 215
 216/* Get v4l2_device related to the notifier if one can be found. */
 217static struct v4l2_device *
 218v4l2_async_notifier_find_v4l2_dev(struct v4l2_async_notifier *notifier)
 219{
 220        while (notifier->parent)
 221                notifier = notifier->parent;
 222
 223        return notifier->v4l2_dev;
 224}
 225
 226/*
 227 * Return true if all child sub-device notifiers are complete, false otherwise.
 228 */
 229static bool
 230v4l2_async_notifier_can_complete(struct v4l2_async_notifier *notifier)
 231{
 232        struct v4l2_subdev *sd;
 233
 234        if (!list_empty(&notifier->waiting))
 235                return false;
 236
 237        list_for_each_entry(sd, &notifier->done, async_list) {
 238                struct v4l2_async_notifier *subdev_notifier =
 239                        v4l2_async_find_subdev_notifier(sd);
 240
 241                if (subdev_notifier &&
 242                    !v4l2_async_notifier_can_complete(subdev_notifier))
 243                        return false;
 244        }
 245
 246        return true;
 247}
 248
 249/*
 250 * Complete the master notifier if possible. This is done when all async
 251 * sub-devices have been bound; v4l2_device is also available then.
 252 */
 253static int
 254v4l2_async_notifier_try_complete(struct v4l2_async_notifier *notifier)
 255{
 256        /* Quick check whether there are still more sub-devices here. */
 257        if (!list_empty(&notifier->waiting))
 258                return 0;
 259
 260        /* Check the entire notifier tree; find the root notifier first. */
 261        while (notifier->parent)
 262                notifier = notifier->parent;
 263
 264        /* This is root if it has v4l2_dev. */
 265        if (!notifier->v4l2_dev)
 266                return 0;
 267
 268        /* Is everything ready? */
 269        if (!v4l2_async_notifier_can_complete(notifier))
 270                return 0;
 271
 272        return v4l2_async_notifier_call_complete(notifier);
 273}
 274
 275static int
 276v4l2_async_notifier_try_all_subdevs(struct v4l2_async_notifier *notifier);
 277
 278static int v4l2_async_match_notify(struct v4l2_async_notifier *notifier,
 279                                   struct v4l2_device *v4l2_dev,
 280                                   struct v4l2_subdev *sd,
 281                                   struct v4l2_async_subdev *asd)
 282{
 283        struct v4l2_async_notifier *subdev_notifier;
 284        int ret;
 285
 286        ret = v4l2_device_register_subdev(v4l2_dev, sd);
 287        if (ret < 0)
 288                return ret;
 289
 290        ret = v4l2_async_notifier_call_bound(notifier, sd, asd);
 291        if (ret < 0) {
 292                v4l2_device_unregister_subdev(sd);
 293                return ret;
 294        }
 295
 296        /* Remove from the waiting list */
 297        list_del(&asd->list);
 298        sd->asd = asd;
 299        sd->notifier = notifier;
 300
 301        /* Move from the global subdevice list to notifier's done */
 302        list_move(&sd->async_list, &notifier->done);
 303
 304        /*
 305         * See if the sub-device has a notifier. If not, return here.
 306         */
 307        subdev_notifier = v4l2_async_find_subdev_notifier(sd);
 308        if (!subdev_notifier || subdev_notifier->parent)
 309                return 0;
 310
 311        /*
 312         * Proceed with checking for the sub-device notifier's async
 313         * sub-devices, and return the result. The error will be handled by the
 314         * caller.
 315         */
 316        subdev_notifier->parent = notifier;
 317
 318        return v4l2_async_notifier_try_all_subdevs(subdev_notifier);
 319}
 320
 321/* Test all async sub-devices in a notifier for a match. */
 322static int
 323v4l2_async_notifier_try_all_subdevs(struct v4l2_async_notifier *notifier)
 324{
 325        struct v4l2_device *v4l2_dev =
 326                v4l2_async_notifier_find_v4l2_dev(notifier);
 327        struct v4l2_subdev *sd;
 328
 329        if (!v4l2_dev)
 330                return 0;
 331
 332again:
 333        list_for_each_entry(sd, &subdev_list, async_list) {
 334                struct v4l2_async_subdev *asd;
 335                int ret;
 336
 337                asd = v4l2_async_find_match(notifier, sd);
 338                if (!asd)
 339                        continue;
 340
 341                ret = v4l2_async_match_notify(notifier, v4l2_dev, sd, asd);
 342                if (ret < 0)
 343                        return ret;
 344
 345                /*
 346                 * v4l2_async_match_notify() may lead to registering a
 347                 * new notifier and thus changing the async subdevs
 348                 * list. In order to proceed safely from here, restart
 349                 * parsing the list from the beginning.
 350                 */
 351                goto again;
 352        }
 353
 354        return 0;
 355}
 356
 357static void v4l2_async_cleanup(struct v4l2_subdev *sd)
 358{
 359        v4l2_device_unregister_subdev(sd);
 360        /*
 361         * Subdevice driver will reprobe and put the subdev back
 362         * onto the list
 363         */
 364        list_del_init(&sd->async_list);
 365        sd->asd = NULL;
 366}
 367
 368/* Unbind all sub-devices in the notifier tree. */
 369static void
 370v4l2_async_notifier_unbind_all_subdevs(struct v4l2_async_notifier *notifier)
 371{
 372        struct v4l2_subdev *sd, *tmp;
 373
 374        list_for_each_entry_safe(sd, tmp, &notifier->done, async_list) {
 375                struct v4l2_async_notifier *subdev_notifier =
 376                        v4l2_async_find_subdev_notifier(sd);
 377
 378                if (subdev_notifier)
 379                        v4l2_async_notifier_unbind_all_subdevs(subdev_notifier);
 380
 381                v4l2_async_notifier_call_unbind(notifier, sd, sd->asd);
 382                v4l2_async_cleanup(sd);
 383
 384                list_move(&sd->async_list, &subdev_list);
 385        }
 386
 387        notifier->parent = NULL;
 388}
 389
 390/* See if an async sub-device can be found in a notifier's lists. */
 391static bool
 392__v4l2_async_notifier_has_async_subdev(struct v4l2_async_notifier *notifier,
 393                                       struct v4l2_async_subdev *asd)
 394{
 395        struct v4l2_async_subdev *asd_y;
 396        struct v4l2_subdev *sd;
 397
 398        list_for_each_entry(asd_y, &notifier->waiting, list)
 399                if (asd_equal(asd, asd_y))
 400                        return true;
 401
 402        list_for_each_entry(sd, &notifier->done, async_list) {
 403                if (WARN_ON(!sd->asd))
 404                        continue;
 405
 406                if (asd_equal(asd, sd->asd))
 407                        return true;
 408        }
 409
 410        return false;
 411}
 412
 413/*
 414 * Find out whether an async sub-device was set up already or
 415 * whether it exists in a given notifier before @this_index.
 416 * If @this_index < 0, search the notifier's entire @asd_list.
 417 */
 418static bool
 419v4l2_async_notifier_has_async_subdev(struct v4l2_async_notifier *notifier,
 420                                     struct v4l2_async_subdev *asd,
 421                                     int this_index)
 422{
 423        struct v4l2_async_subdev *asd_y;
 424        int j = 0;
 425
 426        lockdep_assert_held(&list_lock);
 427
 428        /* Check that an asd is not being added more than once. */
 429        list_for_each_entry(asd_y, &notifier->asd_list, asd_list) {
 430                if (this_index >= 0 && j++ >= this_index)
 431                        break;
 432                if (asd_equal(asd, asd_y))
 433                        return true;
 434        }
 435
 436        /* Check that an asd does not exist in other notifiers. */
 437        list_for_each_entry(notifier, &notifier_list, list)
 438                if (__v4l2_async_notifier_has_async_subdev(notifier, asd))
 439                        return true;
 440
 441        return false;
 442}
 443
 444static int v4l2_async_notifier_asd_valid(struct v4l2_async_notifier *notifier,
 445                                         struct v4l2_async_subdev *asd,
 446                                         int this_index)
 447{
 448        struct device *dev =
 449                notifier->v4l2_dev ? notifier->v4l2_dev->dev : NULL;
 450
 451        if (!asd)
 452                return -EINVAL;
 453
 454        switch (asd->match_type) {
 455        case V4L2_ASYNC_MATCH_I2C:
 456        case V4L2_ASYNC_MATCH_FWNODE:
 457                if (v4l2_async_notifier_has_async_subdev(notifier, asd,
 458                                                         this_index)) {
 459                        dev_dbg(dev, "subdev descriptor already listed in this or other notifiers\n");
 460                        return -EEXIST;
 461                }
 462                break;
 463        default:
 464                dev_err(dev, "Invalid match type %u on %p\n",
 465                        asd->match_type, asd);
 466                return -EINVAL;
 467        }
 468
 469        return 0;
 470}
 471
 472void v4l2_async_notifier_init(struct v4l2_async_notifier *notifier)
 473{
 474        INIT_LIST_HEAD(&notifier->asd_list);
 475}
 476EXPORT_SYMBOL(v4l2_async_notifier_init);
 477
 478static int __v4l2_async_notifier_register(struct v4l2_async_notifier *notifier)
 479{
 480        struct v4l2_async_subdev *asd;
 481        int ret, i = 0;
 482
 483        INIT_LIST_HEAD(&notifier->waiting);
 484        INIT_LIST_HEAD(&notifier->done);
 485
 486        mutex_lock(&list_lock);
 487
 488        list_for_each_entry(asd, &notifier->asd_list, asd_list) {
 489                ret = v4l2_async_notifier_asd_valid(notifier, asd, i++);
 490                if (ret)
 491                        goto err_unlock;
 492
 493                list_add_tail(&asd->list, &notifier->waiting);
 494        }
 495
 496        ret = v4l2_async_notifier_try_all_subdevs(notifier);
 497        if (ret < 0)
 498                goto err_unbind;
 499
 500        ret = v4l2_async_notifier_try_complete(notifier);
 501        if (ret < 0)
 502                goto err_unbind;
 503
 504        /* Keep also completed notifiers on the list */
 505        list_add(&notifier->list, &notifier_list);
 506
 507        mutex_unlock(&list_lock);
 508
 509        return 0;
 510
 511err_unbind:
 512        /*
 513         * On failure, unbind all sub-devices registered through this notifier.
 514         */
 515        v4l2_async_notifier_unbind_all_subdevs(notifier);
 516
 517err_unlock:
 518        mutex_unlock(&list_lock);
 519
 520        return ret;
 521}
 522
 523int v4l2_async_notifier_register(struct v4l2_device *v4l2_dev,
 524                                 struct v4l2_async_notifier *notifier)
 525{
 526        int ret;
 527
 528        if (WARN_ON(!v4l2_dev || notifier->sd))
 529                return -EINVAL;
 530
 531        notifier->v4l2_dev = v4l2_dev;
 532
 533        ret = __v4l2_async_notifier_register(notifier);
 534        if (ret)
 535                notifier->v4l2_dev = NULL;
 536
 537        return ret;
 538}
 539EXPORT_SYMBOL(v4l2_async_notifier_register);
 540
 541int v4l2_async_subdev_notifier_register(struct v4l2_subdev *sd,
 542                                        struct v4l2_async_notifier *notifier)
 543{
 544        int ret;
 545
 546        if (WARN_ON(!sd || notifier->v4l2_dev))
 547                return -EINVAL;
 548
 549        notifier->sd = sd;
 550
 551        ret = __v4l2_async_notifier_register(notifier);
 552        if (ret)
 553                notifier->sd = NULL;
 554
 555        return ret;
 556}
 557EXPORT_SYMBOL(v4l2_async_subdev_notifier_register);
 558
 559static void
 560__v4l2_async_notifier_unregister(struct v4l2_async_notifier *notifier)
 561{
 562        if (!notifier || (!notifier->v4l2_dev && !notifier->sd))
 563                return;
 564
 565        v4l2_async_notifier_unbind_all_subdevs(notifier);
 566
 567        notifier->sd = NULL;
 568        notifier->v4l2_dev = NULL;
 569
 570        list_del(&notifier->list);
 571}
 572
 573void v4l2_async_notifier_unregister(struct v4l2_async_notifier *notifier)
 574{
 575        mutex_lock(&list_lock);
 576
 577        __v4l2_async_notifier_unregister(notifier);
 578
 579        mutex_unlock(&list_lock);
 580}
 581EXPORT_SYMBOL(v4l2_async_notifier_unregister);
 582
 583static void __v4l2_async_notifier_cleanup(struct v4l2_async_notifier *notifier)
 584{
 585        struct v4l2_async_subdev *asd, *tmp;
 586
 587        if (!notifier || !notifier->asd_list.next)
 588                return;
 589
 590        list_for_each_entry_safe(asd, tmp, &notifier->asd_list, asd_list) {
 591                switch (asd->match_type) {
 592                case V4L2_ASYNC_MATCH_FWNODE:
 593                        fwnode_handle_put(asd->match.fwnode);
 594                        break;
 595                default:
 596                        break;
 597                }
 598
 599                list_del(&asd->asd_list);
 600                kfree(asd);
 601        }
 602}
 603
 604void v4l2_async_notifier_cleanup(struct v4l2_async_notifier *notifier)
 605{
 606        mutex_lock(&list_lock);
 607
 608        __v4l2_async_notifier_cleanup(notifier);
 609
 610        mutex_unlock(&list_lock);
 611}
 612EXPORT_SYMBOL_GPL(v4l2_async_notifier_cleanup);
 613
 614int __v4l2_async_notifier_add_subdev(struct v4l2_async_notifier *notifier,
 615                                   struct v4l2_async_subdev *asd)
 616{
 617        int ret;
 618
 619        mutex_lock(&list_lock);
 620
 621        ret = v4l2_async_notifier_asd_valid(notifier, asd, -1);
 622        if (ret)
 623                goto unlock;
 624
 625        list_add_tail(&asd->asd_list, &notifier->asd_list);
 626
 627unlock:
 628        mutex_unlock(&list_lock);
 629        return ret;
 630}
 631EXPORT_SYMBOL_GPL(__v4l2_async_notifier_add_subdev);
 632
 633struct v4l2_async_subdev *
 634__v4l2_async_notifier_add_fwnode_subdev(struct v4l2_async_notifier *notifier,
 635                                        struct fwnode_handle *fwnode,
 636                                        unsigned int asd_struct_size)
 637{
 638        struct v4l2_async_subdev *asd;
 639        int ret;
 640
 641        asd = kzalloc(asd_struct_size, GFP_KERNEL);
 642        if (!asd)
 643                return ERR_PTR(-ENOMEM);
 644
 645        asd->match_type = V4L2_ASYNC_MATCH_FWNODE;
 646        asd->match.fwnode = fwnode_handle_get(fwnode);
 647
 648        ret = __v4l2_async_notifier_add_subdev(notifier, asd);
 649        if (ret) {
 650                fwnode_handle_put(fwnode);
 651                kfree(asd);
 652                return ERR_PTR(ret);
 653        }
 654
 655        return asd;
 656}
 657EXPORT_SYMBOL_GPL(__v4l2_async_notifier_add_fwnode_subdev);
 658
 659struct v4l2_async_subdev *
 660__v4l2_async_notifier_add_fwnode_remote_subdev(struct v4l2_async_notifier *notif,
 661                                               struct fwnode_handle *endpoint,
 662                                               unsigned int asd_struct_size)
 663{
 664        struct v4l2_async_subdev *asd;
 665        struct fwnode_handle *remote;
 666
 667        remote = fwnode_graph_get_remote_port_parent(endpoint);
 668        if (!remote)
 669                return ERR_PTR(-ENOTCONN);
 670
 671        asd = __v4l2_async_notifier_add_fwnode_subdev(notif, remote,
 672                                                      asd_struct_size);
 673        /*
 674         * Calling __v4l2_async_notifier_add_fwnode_subdev grabs a refcount,
 675         * so drop the one we got in fwnode_graph_get_remote_port_parent.
 676         */
 677        fwnode_handle_put(remote);
 678        return asd;
 679}
 680EXPORT_SYMBOL_GPL(__v4l2_async_notifier_add_fwnode_remote_subdev);
 681
 682struct v4l2_async_subdev *
 683__v4l2_async_notifier_add_i2c_subdev(struct v4l2_async_notifier *notifier,
 684                                     int adapter_id, unsigned short address,
 685                                     unsigned int asd_struct_size)
 686{
 687        struct v4l2_async_subdev *asd;
 688        int ret;
 689
 690        asd = kzalloc(asd_struct_size, GFP_KERNEL);
 691        if (!asd)
 692                return ERR_PTR(-ENOMEM);
 693
 694        asd->match_type = V4L2_ASYNC_MATCH_I2C;
 695        asd->match.i2c.adapter_id = adapter_id;
 696        asd->match.i2c.address = address;
 697
 698        ret = __v4l2_async_notifier_add_subdev(notifier, asd);
 699        if (ret) {
 700                kfree(asd);
 701                return ERR_PTR(ret);
 702        }
 703
 704        return asd;
 705}
 706EXPORT_SYMBOL_GPL(__v4l2_async_notifier_add_i2c_subdev);
 707
 708int v4l2_async_register_subdev(struct v4l2_subdev *sd)
 709{
 710        struct v4l2_async_notifier *subdev_notifier;
 711        struct v4l2_async_notifier *notifier;
 712        int ret;
 713
 714        /*
 715         * No reference taken. The reference is held by the device
 716         * (struct v4l2_subdev.dev), and async sub-device does not
 717         * exist independently of the device at any point of time.
 718         */
 719        if (!sd->fwnode && sd->dev)
 720                sd->fwnode = dev_fwnode(sd->dev);
 721
 722        mutex_lock(&list_lock);
 723
 724        INIT_LIST_HEAD(&sd->async_list);
 725
 726        list_for_each_entry(notifier, &notifier_list, list) {
 727                struct v4l2_device *v4l2_dev =
 728                        v4l2_async_notifier_find_v4l2_dev(notifier);
 729                struct v4l2_async_subdev *asd;
 730
 731                if (!v4l2_dev)
 732                        continue;
 733
 734                asd = v4l2_async_find_match(notifier, sd);
 735                if (!asd)
 736                        continue;
 737
 738                ret = v4l2_async_match_notify(notifier, v4l2_dev, sd, asd);
 739                if (ret)
 740                        goto err_unbind;
 741
 742                ret = v4l2_async_notifier_try_complete(notifier);
 743                if (ret)
 744                        goto err_unbind;
 745
 746                goto out_unlock;
 747        }
 748
 749        /* None matched, wait for hot-plugging */
 750        list_add(&sd->async_list, &subdev_list);
 751
 752out_unlock:
 753        mutex_unlock(&list_lock);
 754
 755        return 0;
 756
 757err_unbind:
 758        /*
 759         * Complete failed. Unbind the sub-devices bound through registering
 760         * this async sub-device.
 761         */
 762        subdev_notifier = v4l2_async_find_subdev_notifier(sd);
 763        if (subdev_notifier)
 764                v4l2_async_notifier_unbind_all_subdevs(subdev_notifier);
 765
 766        if (sd->asd)
 767                v4l2_async_notifier_call_unbind(notifier, sd, sd->asd);
 768        v4l2_async_cleanup(sd);
 769
 770        mutex_unlock(&list_lock);
 771
 772        return ret;
 773}
 774EXPORT_SYMBOL(v4l2_async_register_subdev);
 775
 776void v4l2_async_unregister_subdev(struct v4l2_subdev *sd)
 777{
 778        if (!sd->async_list.next)
 779                return;
 780
 781        mutex_lock(&list_lock);
 782
 783        __v4l2_async_notifier_unregister(sd->subdev_notifier);
 784        __v4l2_async_notifier_cleanup(sd->subdev_notifier);
 785        kfree(sd->subdev_notifier);
 786        sd->subdev_notifier = NULL;
 787
 788        if (sd->asd) {
 789                struct v4l2_async_notifier *notifier = sd->notifier;
 790
 791                list_add(&sd->asd->list, &notifier->waiting);
 792
 793                v4l2_async_notifier_call_unbind(notifier, sd, sd->asd);
 794        }
 795
 796        v4l2_async_cleanup(sd);
 797
 798        mutex_unlock(&list_lock);
 799}
 800EXPORT_SYMBOL(v4l2_async_unregister_subdev);
 801
 802static void print_waiting_subdev(struct seq_file *s,
 803                                 struct v4l2_async_subdev *asd)
 804{
 805        switch (asd->match_type) {
 806        case V4L2_ASYNC_MATCH_I2C:
 807                seq_printf(s, " [i2c] dev=%d-%04x\n", asd->match.i2c.adapter_id,
 808                           asd->match.i2c.address);
 809                break;
 810        case V4L2_ASYNC_MATCH_FWNODE: {
 811                struct fwnode_handle *devnode, *fwnode = asd->match.fwnode;
 812
 813                devnode = fwnode_graph_is_endpoint(fwnode) ?
 814                          fwnode_graph_get_port_parent(fwnode) :
 815                          fwnode_handle_get(fwnode);
 816
 817                seq_printf(s, " [fwnode] dev=%s, node=%pfw\n",
 818                           devnode->dev ? dev_name(devnode->dev) : "nil",
 819                           fwnode);
 820
 821                fwnode_handle_put(devnode);
 822                break;
 823        }
 824        }
 825}
 826
 827static const char *
 828v4l2_async_notifier_name(struct v4l2_async_notifier *notifier)
 829{
 830        if (notifier->v4l2_dev)
 831                return notifier->v4l2_dev->name;
 832        else if (notifier->sd)
 833                return notifier->sd->name;
 834        else
 835                return "nil";
 836}
 837
 838static int pending_subdevs_show(struct seq_file *s, void *data)
 839{
 840        struct v4l2_async_notifier *notif;
 841        struct v4l2_async_subdev *asd;
 842
 843        mutex_lock(&list_lock);
 844
 845        list_for_each_entry(notif, &notifier_list, list) {
 846                seq_printf(s, "%s:\n", v4l2_async_notifier_name(notif));
 847                list_for_each_entry(asd, &notif->waiting, list)
 848                        print_waiting_subdev(s, asd);
 849        }
 850
 851        mutex_unlock(&list_lock);
 852
 853        return 0;
 854}
 855DEFINE_SHOW_ATTRIBUTE(pending_subdevs);
 856
 857void v4l2_async_debug_init(struct dentry *debugfs_dir)
 858{
 859        debugfs_create_file("pending_async_subdevices", 0444, debugfs_dir, NULL,
 860                            &pending_subdevs_fops);
 861}
 862