1 // SPDX-License-Identifier: GPL-2.0-only
3 * V4L2 asynchronous subdevice registration API
5 * Copyright (C) 2012-2013, Guennadi Liakhovetski <g.liakhovetski@gmx.de>
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>
14 #include <linux/module.h>
15 #include <linux/mutex.h>
17 #include <linux/platform_device.h>
18 #include <linux/seq_file.h>
19 #include <linux/slab.h>
20 #include <linux/types.h>
22 #include <media/v4l2-async.h>
23 #include <media/v4l2-device.h>
24 #include <media/v4l2-fwnode.h>
25 #include <media/v4l2-subdev.h>
27 static int v4l2_async_notifier_call_bound(struct v4l2_async_notifier *n,
28 struct v4l2_subdev *subdev,
29 struct v4l2_async_subdev *asd)
31 if (!n->ops || !n->ops->bound)
34 return n->ops->bound(n, subdev, asd);
37 static void v4l2_async_notifier_call_unbind(struct v4l2_async_notifier *n,
38 struct v4l2_subdev *subdev,
39 struct v4l2_async_subdev *asd)
41 if (!n->ops || !n->ops->unbind)
44 n->ops->unbind(n, subdev, asd);
47 static int v4l2_async_notifier_call_complete(struct v4l2_async_notifier *n)
49 if (!n->ops || !n->ops->complete)
52 return n->ops->complete(n);
55 static bool match_i2c(struct v4l2_async_notifier *notifier,
56 struct v4l2_subdev *sd, struct v4l2_async_subdev *asd)
58 #if IS_ENABLED(CONFIG_I2C)
59 struct i2c_client *client = i2c_verify_client(sd->dev);
62 asd->match.i2c.adapter_id == client->adapter->nr &&
63 asd->match.i2c.address == client->addr;
69 static bool match_fwnode(struct v4l2_async_notifier *notifier,
70 struct v4l2_subdev *sd, struct v4l2_async_subdev *asd)
72 struct fwnode_handle *other_fwnode;
73 struct fwnode_handle *dev_fwnode;
74 bool asd_fwnode_is_ep;
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
83 if (sd->fwnode == asd->match.fwnode)
87 * Check the same situation for any possible secondary assigned to the
90 if (!IS_ERR_OR_NULL(sd->fwnode->secondary) &&
91 sd->fwnode->secondary == asd->match.fwnode)
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.
102 sd_fwnode_is_ep = fwnode_graph_is_endpoint(sd->fwnode);
103 asd_fwnode_is_ep = fwnode_graph_is_endpoint(asd->match.fwnode);
105 if (sd_fwnode_is_ep == asd_fwnode_is_ep)
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.
112 if (sd_fwnode_is_ep) {
113 dev_fwnode = fwnode_graph_get_port_parent(sd->fwnode);
114 other_fwnode = asd->match.fwnode;
116 dev_fwnode = fwnode_graph_get_port_parent(asd->match.fwnode);
117 other_fwnode = sd->fwnode;
120 fwnode_handle_put(dev_fwnode);
122 if (dev_fwnode != other_fwnode)
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.
130 dev = notifier->v4l2_dev ? notifier->v4l2_dev->dev
135 if (dev && dev->driver) {
137 dev_warn(dev, "Driver %s uses device fwnode, incorrect match may occur\n",
139 dev_notice(dev, "Consider updating driver %s to match on endpoints\n",
146 static LIST_HEAD(subdev_list);
147 static LIST_HEAD(notifier_list);
148 static DEFINE_MUTEX(list_lock);
150 static struct v4l2_async_subdev *
151 v4l2_async_find_match(struct v4l2_async_notifier *notifier,
152 struct v4l2_subdev *sd)
154 bool (*match)(struct v4l2_async_notifier *notifier,
155 struct v4l2_subdev *sd, struct v4l2_async_subdev *asd);
156 struct v4l2_async_subdev *asd;
158 list_for_each_entry(asd, ¬ifier->waiting, list) {
159 /* bus_type has been verified valid before */
160 switch (asd->match_type) {
161 case V4L2_ASYNC_MATCH_I2C:
164 case V4L2_ASYNC_MATCH_FWNODE:
165 match = match_fwnode;
168 /* Cannot happen, unless someone breaks us */
173 /* match cannot be NULL here */
174 if (match(notifier, sd, asd))
181 /* Compare two async sub-device descriptors for equivalence */
182 static bool asd_equal(struct v4l2_async_subdev *asd_x,
183 struct v4l2_async_subdev *asd_y)
185 if (asd_x->match_type != asd_y->match_type)
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;
203 /* Find the sub-device notifier registered by a sub-device driver. */
204 static struct v4l2_async_notifier *
205 v4l2_async_find_subdev_notifier(struct v4l2_subdev *sd)
207 struct v4l2_async_notifier *n;
209 list_for_each_entry(n, ¬ifier_list, list)
216 /* Get v4l2_device related to the notifier if one can be found. */
217 static struct v4l2_device *
218 v4l2_async_notifier_find_v4l2_dev(struct v4l2_async_notifier *notifier)
220 while (notifier->parent)
221 notifier = notifier->parent;
223 return notifier->v4l2_dev;
227 * Return true if all child sub-device notifiers are complete, false otherwise.
230 v4l2_async_notifier_can_complete(struct v4l2_async_notifier *notifier)
232 struct v4l2_subdev *sd;
234 if (!list_empty(¬ifier->waiting))
237 list_for_each_entry(sd, ¬ifier->done, async_list) {
238 struct v4l2_async_notifier *subdev_notifier =
239 v4l2_async_find_subdev_notifier(sd);
241 if (subdev_notifier &&
242 !v4l2_async_notifier_can_complete(subdev_notifier))
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.
254 v4l2_async_notifier_try_complete(struct v4l2_async_notifier *notifier)
256 /* Quick check whether there are still more sub-devices here. */
257 if (!list_empty(¬ifier->waiting))
260 /* Check the entire notifier tree; find the root notifier first. */
261 while (notifier->parent)
262 notifier = notifier->parent;
264 /* This is root if it has v4l2_dev. */
265 if (!notifier->v4l2_dev)
268 /* Is everything ready? */
269 if (!v4l2_async_notifier_can_complete(notifier))
272 return v4l2_async_notifier_call_complete(notifier);
276 v4l2_async_notifier_try_all_subdevs(struct v4l2_async_notifier *notifier);
278 static int v4l2_async_create_ancillary_links(struct v4l2_async_notifier *n,
279 struct v4l2_subdev *sd)
281 struct media_link *link = NULL;
283 #if IS_ENABLED(CONFIG_MEDIA_CONTROLLER)
285 if (sd->entity.function != MEDIA_ENT_F_LENS &&
286 sd->entity.function != MEDIA_ENT_F_FLASH)
289 link = media_create_ancillary_link(&n->sd->entity, &sd->entity);
293 return IS_ERR(link) ? PTR_ERR(link) : 0;
296 static int v4l2_async_match_notify(struct v4l2_async_notifier *notifier,
297 struct v4l2_device *v4l2_dev,
298 struct v4l2_subdev *sd,
299 struct v4l2_async_subdev *asd)
301 struct v4l2_async_notifier *subdev_notifier;
304 ret = v4l2_device_register_subdev(v4l2_dev, sd);
308 ret = v4l2_async_notifier_call_bound(notifier, sd, asd);
310 v4l2_device_unregister_subdev(sd);
315 * Depending of the function of the entities involved, we may want to
316 * create links between them (for example between a sensor and its lens
317 * or between a sensor's source pad and the connected device's sink
320 ret = v4l2_async_create_ancillary_links(notifier, sd);
322 v4l2_async_notifier_call_unbind(notifier, sd, asd);
323 v4l2_device_unregister_subdev(sd);
327 /* Remove from the waiting list */
328 list_del(&asd->list);
330 sd->notifier = notifier;
332 /* Move from the global subdevice list to notifier's done */
333 list_move(&sd->async_list, ¬ifier->done);
336 * See if the sub-device has a notifier. If not, return here.
338 subdev_notifier = v4l2_async_find_subdev_notifier(sd);
339 if (!subdev_notifier || subdev_notifier->parent)
343 * Proceed with checking for the sub-device notifier's async
344 * sub-devices, and return the result. The error will be handled by the
347 subdev_notifier->parent = notifier;
349 return v4l2_async_notifier_try_all_subdevs(subdev_notifier);
352 /* Test all async sub-devices in a notifier for a match. */
354 v4l2_async_notifier_try_all_subdevs(struct v4l2_async_notifier *notifier)
356 struct v4l2_device *v4l2_dev =
357 v4l2_async_notifier_find_v4l2_dev(notifier);
358 struct v4l2_subdev *sd;
364 list_for_each_entry(sd, &subdev_list, async_list) {
365 struct v4l2_async_subdev *asd;
368 asd = v4l2_async_find_match(notifier, sd);
372 ret = v4l2_async_match_notify(notifier, v4l2_dev, sd, asd);
377 * v4l2_async_match_notify() may lead to registering a
378 * new notifier and thus changing the async subdevs
379 * list. In order to proceed safely from here, restart
380 * parsing the list from the beginning.
388 static void v4l2_async_cleanup(struct v4l2_subdev *sd)
390 v4l2_device_unregister_subdev(sd);
392 * Subdevice driver will reprobe and put the subdev back
395 list_del_init(&sd->async_list);
399 /* Unbind all sub-devices in the notifier tree. */
401 v4l2_async_notifier_unbind_all_subdevs(struct v4l2_async_notifier *notifier)
403 struct v4l2_subdev *sd, *tmp;
405 list_for_each_entry_safe(sd, tmp, ¬ifier->done, async_list) {
406 struct v4l2_async_notifier *subdev_notifier =
407 v4l2_async_find_subdev_notifier(sd);
410 v4l2_async_notifier_unbind_all_subdevs(subdev_notifier);
412 v4l2_async_notifier_call_unbind(notifier, sd, sd->asd);
413 v4l2_async_cleanup(sd);
415 list_move(&sd->async_list, &subdev_list);
418 notifier->parent = NULL;
421 /* See if an async sub-device can be found in a notifier's lists. */
423 __v4l2_async_notifier_has_async_subdev(struct v4l2_async_notifier *notifier,
424 struct v4l2_async_subdev *asd)
426 struct v4l2_async_subdev *asd_y;
427 struct v4l2_subdev *sd;
429 list_for_each_entry(asd_y, ¬ifier->waiting, list)
430 if (asd_equal(asd, asd_y))
433 list_for_each_entry(sd, ¬ifier->done, async_list) {
434 if (WARN_ON(!sd->asd))
437 if (asd_equal(asd, sd->asd))
445 * Find out whether an async sub-device was set up already or
446 * whether it exists in a given notifier before @this_index.
447 * If @this_index < 0, search the notifier's entire @asd_list.
450 v4l2_async_notifier_has_async_subdev(struct v4l2_async_notifier *notifier,
451 struct v4l2_async_subdev *asd,
454 struct v4l2_async_subdev *asd_y;
457 lockdep_assert_held(&list_lock);
459 /* Check that an asd is not being added more than once. */
460 list_for_each_entry(asd_y, ¬ifier->asd_list, asd_list) {
461 if (this_index >= 0 && j++ >= this_index)
463 if (asd_equal(asd, asd_y))
467 /* Check that an asd does not exist in other notifiers. */
468 list_for_each_entry(notifier, ¬ifier_list, list)
469 if (__v4l2_async_notifier_has_async_subdev(notifier, asd))
475 static int v4l2_async_notifier_asd_valid(struct v4l2_async_notifier *notifier,
476 struct v4l2_async_subdev *asd,
480 notifier->v4l2_dev ? notifier->v4l2_dev->dev : NULL;
485 switch (asd->match_type) {
486 case V4L2_ASYNC_MATCH_I2C:
487 case V4L2_ASYNC_MATCH_FWNODE:
488 if (v4l2_async_notifier_has_async_subdev(notifier, asd,
490 dev_dbg(dev, "subdev descriptor already listed in this or other notifiers\n");
495 dev_err(dev, "Invalid match type %u on %p\n",
496 asd->match_type, asd);
503 void v4l2_async_notifier_init(struct v4l2_async_notifier *notifier)
505 INIT_LIST_HEAD(¬ifier->asd_list);
507 EXPORT_SYMBOL(v4l2_async_notifier_init);
509 static int __v4l2_async_notifier_register(struct v4l2_async_notifier *notifier)
511 struct v4l2_async_subdev *asd;
514 INIT_LIST_HEAD(¬ifier->waiting);
515 INIT_LIST_HEAD(¬ifier->done);
517 mutex_lock(&list_lock);
519 list_for_each_entry(asd, ¬ifier->asd_list, asd_list) {
520 ret = v4l2_async_notifier_asd_valid(notifier, asd, i++);
524 list_add_tail(&asd->list, ¬ifier->waiting);
527 ret = v4l2_async_notifier_try_all_subdevs(notifier);
531 ret = v4l2_async_notifier_try_complete(notifier);
535 /* Keep also completed notifiers on the list */
536 list_add(¬ifier->list, ¬ifier_list);
538 mutex_unlock(&list_lock);
544 * On failure, unbind all sub-devices registered through this notifier.
546 v4l2_async_notifier_unbind_all_subdevs(notifier);
549 mutex_unlock(&list_lock);
554 int v4l2_async_notifier_register(struct v4l2_device *v4l2_dev,
555 struct v4l2_async_notifier *notifier)
559 if (WARN_ON(!v4l2_dev || notifier->sd))
562 notifier->v4l2_dev = v4l2_dev;
564 ret = __v4l2_async_notifier_register(notifier);
566 notifier->v4l2_dev = NULL;
570 EXPORT_SYMBOL(v4l2_async_notifier_register);
572 int v4l2_async_subdev_notifier_register(struct v4l2_subdev *sd,
573 struct v4l2_async_notifier *notifier)
577 if (WARN_ON(!sd || notifier->v4l2_dev))
582 ret = __v4l2_async_notifier_register(notifier);
588 EXPORT_SYMBOL(v4l2_async_subdev_notifier_register);
591 __v4l2_async_notifier_unregister(struct v4l2_async_notifier *notifier)
593 if (!notifier || (!notifier->v4l2_dev && !notifier->sd))
596 v4l2_async_notifier_unbind_all_subdevs(notifier);
599 notifier->v4l2_dev = NULL;
601 list_del(¬ifier->list);
604 void v4l2_async_notifier_unregister(struct v4l2_async_notifier *notifier)
606 mutex_lock(&list_lock);
608 __v4l2_async_notifier_unregister(notifier);
610 mutex_unlock(&list_lock);
612 EXPORT_SYMBOL(v4l2_async_notifier_unregister);
614 static void __v4l2_async_notifier_cleanup(struct v4l2_async_notifier *notifier)
616 struct v4l2_async_subdev *asd, *tmp;
618 if (!notifier || !notifier->asd_list.next)
621 list_for_each_entry_safe(asd, tmp, ¬ifier->asd_list, asd_list) {
622 switch (asd->match_type) {
623 case V4L2_ASYNC_MATCH_FWNODE:
624 fwnode_handle_put(asd->match.fwnode);
630 list_del(&asd->asd_list);
635 void v4l2_async_notifier_cleanup(struct v4l2_async_notifier *notifier)
637 mutex_lock(&list_lock);
639 __v4l2_async_notifier_cleanup(notifier);
641 mutex_unlock(&list_lock);
643 EXPORT_SYMBOL_GPL(v4l2_async_notifier_cleanup);
645 int __v4l2_async_notifier_add_subdev(struct v4l2_async_notifier *notifier,
646 struct v4l2_async_subdev *asd)
650 mutex_lock(&list_lock);
652 ret = v4l2_async_notifier_asd_valid(notifier, asd, -1);
656 list_add_tail(&asd->asd_list, ¬ifier->asd_list);
659 mutex_unlock(&list_lock);
662 EXPORT_SYMBOL_GPL(__v4l2_async_notifier_add_subdev);
664 struct v4l2_async_subdev *
665 __v4l2_async_notifier_add_fwnode_subdev(struct v4l2_async_notifier *notifier,
666 struct fwnode_handle *fwnode,
667 unsigned int asd_struct_size)
669 struct v4l2_async_subdev *asd;
672 asd = kzalloc(asd_struct_size, GFP_KERNEL);
674 return ERR_PTR(-ENOMEM);
676 asd->match_type = V4L2_ASYNC_MATCH_FWNODE;
677 asd->match.fwnode = fwnode_handle_get(fwnode);
679 ret = __v4l2_async_notifier_add_subdev(notifier, asd);
681 fwnode_handle_put(fwnode);
688 EXPORT_SYMBOL_GPL(__v4l2_async_notifier_add_fwnode_subdev);
690 struct v4l2_async_subdev *
691 __v4l2_async_notifier_add_fwnode_remote_subdev(struct v4l2_async_notifier *notif,
692 struct fwnode_handle *endpoint,
693 unsigned int asd_struct_size)
695 struct v4l2_async_subdev *asd;
696 struct fwnode_handle *remote;
698 remote = fwnode_graph_get_remote_port_parent(endpoint);
700 return ERR_PTR(-ENOTCONN);
702 asd = __v4l2_async_notifier_add_fwnode_subdev(notif, remote,
705 * Calling __v4l2_async_notifier_add_fwnode_subdev grabs a refcount,
706 * so drop the one we got in fwnode_graph_get_remote_port_parent.
708 fwnode_handle_put(remote);
711 EXPORT_SYMBOL_GPL(__v4l2_async_notifier_add_fwnode_remote_subdev);
713 struct v4l2_async_subdev *
714 __v4l2_async_notifier_add_i2c_subdev(struct v4l2_async_notifier *notifier,
715 int adapter_id, unsigned short address,
716 unsigned int asd_struct_size)
718 struct v4l2_async_subdev *asd;
721 asd = kzalloc(asd_struct_size, GFP_KERNEL);
723 return ERR_PTR(-ENOMEM);
725 asd->match_type = V4L2_ASYNC_MATCH_I2C;
726 asd->match.i2c.adapter_id = adapter_id;
727 asd->match.i2c.address = address;
729 ret = __v4l2_async_notifier_add_subdev(notifier, asd);
737 EXPORT_SYMBOL_GPL(__v4l2_async_notifier_add_i2c_subdev);
739 int v4l2_async_register_subdev(struct v4l2_subdev *sd)
741 struct v4l2_async_notifier *subdev_notifier;
742 struct v4l2_async_notifier *notifier;
746 * No reference taken. The reference is held by the device
747 * (struct v4l2_subdev.dev), and async sub-device does not
748 * exist independently of the device at any point of time.
750 if (!sd->fwnode && sd->dev)
751 sd->fwnode = dev_fwnode(sd->dev);
753 mutex_lock(&list_lock);
755 INIT_LIST_HEAD(&sd->async_list);
757 list_for_each_entry(notifier, ¬ifier_list, list) {
758 struct v4l2_device *v4l2_dev =
759 v4l2_async_notifier_find_v4l2_dev(notifier);
760 struct v4l2_async_subdev *asd;
765 asd = v4l2_async_find_match(notifier, sd);
769 ret = v4l2_async_match_notify(notifier, v4l2_dev, sd, asd);
773 ret = v4l2_async_notifier_try_complete(notifier);
780 /* None matched, wait for hot-plugging */
781 list_add(&sd->async_list, &subdev_list);
784 mutex_unlock(&list_lock);
790 * Complete failed. Unbind the sub-devices bound through registering
791 * this async sub-device.
793 subdev_notifier = v4l2_async_find_subdev_notifier(sd);
795 v4l2_async_notifier_unbind_all_subdevs(subdev_notifier);
798 v4l2_async_notifier_call_unbind(notifier, sd, sd->asd);
799 v4l2_async_cleanup(sd);
801 mutex_unlock(&list_lock);
805 EXPORT_SYMBOL(v4l2_async_register_subdev);
807 void v4l2_async_unregister_subdev(struct v4l2_subdev *sd)
809 if (!sd->async_list.next)
812 mutex_lock(&list_lock);
814 __v4l2_async_notifier_unregister(sd->subdev_notifier);
815 __v4l2_async_notifier_cleanup(sd->subdev_notifier);
816 kfree(sd->subdev_notifier);
817 sd->subdev_notifier = NULL;
820 struct v4l2_async_notifier *notifier = sd->notifier;
822 list_add(&sd->asd->list, ¬ifier->waiting);
824 v4l2_async_notifier_call_unbind(notifier, sd, sd->asd);
827 v4l2_async_cleanup(sd);
829 mutex_unlock(&list_lock);
831 EXPORT_SYMBOL(v4l2_async_unregister_subdev);
833 static void print_waiting_subdev(struct seq_file *s,
834 struct v4l2_async_subdev *asd)
836 switch (asd->match_type) {
837 case V4L2_ASYNC_MATCH_I2C:
838 seq_printf(s, " [i2c] dev=%d-%04x\n", asd->match.i2c.adapter_id,
839 asd->match.i2c.address);
841 case V4L2_ASYNC_MATCH_FWNODE: {
842 struct fwnode_handle *devnode, *fwnode = asd->match.fwnode;
844 devnode = fwnode_graph_is_endpoint(fwnode) ?
845 fwnode_graph_get_port_parent(fwnode) :
846 fwnode_handle_get(fwnode);
848 seq_printf(s, " [fwnode] dev=%s, node=%pfw\n",
849 devnode->dev ? dev_name(devnode->dev) : "nil",
852 fwnode_handle_put(devnode);
859 v4l2_async_notifier_name(struct v4l2_async_notifier *notifier)
861 if (notifier->v4l2_dev)
862 return notifier->v4l2_dev->name;
863 else if (notifier->sd)
864 return notifier->sd->name;
869 static int pending_subdevs_show(struct seq_file *s, void *data)
871 struct v4l2_async_notifier *notif;
872 struct v4l2_async_subdev *asd;
874 mutex_lock(&list_lock);
876 list_for_each_entry(notif, ¬ifier_list, list) {
877 seq_printf(s, "%s:\n", v4l2_async_notifier_name(notif));
878 list_for_each_entry(asd, ¬if->waiting, list)
879 print_waiting_subdev(s, asd);
882 mutex_unlock(&list_lock);
886 DEFINE_SHOW_ATTRIBUTE(pending_subdevs);
888 static struct dentry *v4l2_async_debugfs_dir;
890 static int __init v4l2_async_init(void)
892 v4l2_async_debugfs_dir = debugfs_create_dir("v4l2-async", NULL);
893 debugfs_create_file("pending_async_subdevices", 0444,
894 v4l2_async_debugfs_dir, NULL,
895 &pending_subdevs_fops);
900 static void __exit v4l2_async_exit(void)
902 debugfs_remove_recursive(v4l2_async_debugfs_dir);
905 subsys_initcall(v4l2_async_init);
906 module_exit(v4l2_async_exit);
908 MODULE_AUTHOR("Guennadi Liakhovetski <g.liakhovetski@gmx.de>");
909 MODULE_AUTHOR("Sakari Ailus <sakari.ailus@linux.intel.com>");
910 MODULE_AUTHOR("Ezequiel Garcia <ezequiel@collabora.com>");
911 MODULE_LICENSE("GPL");