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_nf_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_nf_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_nf_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_nf_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_nf_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_nf_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_nf_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_nf_can_complete(notifier))
272 return v4l2_async_nf_call_complete(notifier);
276 v4l2_async_nf_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_nf_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_nf_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_nf_try_all_subdevs(subdev_notifier);
352 /* Test all async sub-devices in a notifier for a match. */
354 v4l2_async_nf_try_all_subdevs(struct v4l2_async_notifier *notifier)
356 struct v4l2_device *v4l2_dev =
357 v4l2_async_nf_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_nf_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_nf_unbind_all_subdevs(subdev_notifier);
412 v4l2_async_nf_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_nf_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_nf_has_async_subdev(struct v4l2_async_notifier *notifier,
451 struct v4l2_async_subdev *asd, int this_index)
453 struct v4l2_async_subdev *asd_y;
456 lockdep_assert_held(&list_lock);
458 /* Check that an asd is not being added more than once. */
459 list_for_each_entry(asd_y, ¬ifier->asd_list, asd_list) {
460 if (this_index >= 0 && j++ >= this_index)
462 if (asd_equal(asd, asd_y))
466 /* Check that an asd does not exist in other notifiers. */
467 list_for_each_entry(notifier, ¬ifier_list, list)
468 if (__v4l2_async_nf_has_async_subdev(notifier, asd))
474 static int v4l2_async_nf_asd_valid(struct v4l2_async_notifier *notifier,
475 struct v4l2_async_subdev *asd,
479 notifier->v4l2_dev ? notifier->v4l2_dev->dev : NULL;
484 switch (asd->match_type) {
485 case V4L2_ASYNC_MATCH_I2C:
486 case V4L2_ASYNC_MATCH_FWNODE:
487 if (v4l2_async_nf_has_async_subdev(notifier, asd, this_index)) {
488 dev_dbg(dev, "subdev descriptor already listed in this or other notifiers\n");
493 dev_err(dev, "Invalid match type %u on %p\n",
494 asd->match_type, asd);
501 void v4l2_async_nf_init(struct v4l2_async_notifier *notifier)
503 INIT_LIST_HEAD(¬ifier->asd_list);
505 EXPORT_SYMBOL(v4l2_async_nf_init);
507 static int __v4l2_async_nf_register(struct v4l2_async_notifier *notifier)
509 struct v4l2_async_subdev *asd;
512 INIT_LIST_HEAD(¬ifier->waiting);
513 INIT_LIST_HEAD(¬ifier->done);
515 mutex_lock(&list_lock);
517 list_for_each_entry(asd, ¬ifier->asd_list, asd_list) {
518 ret = v4l2_async_nf_asd_valid(notifier, asd, i++);
522 list_add_tail(&asd->list, ¬ifier->waiting);
525 ret = v4l2_async_nf_try_all_subdevs(notifier);
529 ret = v4l2_async_nf_try_complete(notifier);
533 /* Keep also completed notifiers on the list */
534 list_add(¬ifier->list, ¬ifier_list);
536 mutex_unlock(&list_lock);
542 * On failure, unbind all sub-devices registered through this notifier.
544 v4l2_async_nf_unbind_all_subdevs(notifier);
547 mutex_unlock(&list_lock);
552 int v4l2_async_nf_register(struct v4l2_device *v4l2_dev,
553 struct v4l2_async_notifier *notifier)
557 if (WARN_ON(!v4l2_dev || notifier->sd))
560 notifier->v4l2_dev = v4l2_dev;
562 ret = __v4l2_async_nf_register(notifier);
564 notifier->v4l2_dev = NULL;
568 EXPORT_SYMBOL(v4l2_async_nf_register);
570 int v4l2_async_subdev_nf_register(struct v4l2_subdev *sd,
571 struct v4l2_async_notifier *notifier)
575 if (WARN_ON(!sd || notifier->v4l2_dev))
580 ret = __v4l2_async_nf_register(notifier);
586 EXPORT_SYMBOL(v4l2_async_subdev_nf_register);
589 __v4l2_async_nf_unregister(struct v4l2_async_notifier *notifier)
591 if (!notifier || (!notifier->v4l2_dev && !notifier->sd))
594 v4l2_async_nf_unbind_all_subdevs(notifier);
597 notifier->v4l2_dev = NULL;
599 list_del(¬ifier->list);
602 void v4l2_async_nf_unregister(struct v4l2_async_notifier *notifier)
604 mutex_lock(&list_lock);
606 __v4l2_async_nf_unregister(notifier);
608 mutex_unlock(&list_lock);
610 EXPORT_SYMBOL(v4l2_async_nf_unregister);
612 static void __v4l2_async_nf_cleanup(struct v4l2_async_notifier *notifier)
614 struct v4l2_async_subdev *asd, *tmp;
616 if (!notifier || !notifier->asd_list.next)
619 list_for_each_entry_safe(asd, tmp, ¬ifier->asd_list, asd_list) {
620 switch (asd->match_type) {
621 case V4L2_ASYNC_MATCH_FWNODE:
622 fwnode_handle_put(asd->match.fwnode);
628 list_del(&asd->asd_list);
633 void v4l2_async_nf_cleanup(struct v4l2_async_notifier *notifier)
635 mutex_lock(&list_lock);
637 __v4l2_async_nf_cleanup(notifier);
639 mutex_unlock(&list_lock);
641 EXPORT_SYMBOL_GPL(v4l2_async_nf_cleanup);
643 int __v4l2_async_nf_add_subdev(struct v4l2_async_notifier *notifier,
644 struct v4l2_async_subdev *asd)
648 mutex_lock(&list_lock);
650 ret = v4l2_async_nf_asd_valid(notifier, asd, -1);
654 list_add_tail(&asd->asd_list, ¬ifier->asd_list);
657 mutex_unlock(&list_lock);
660 EXPORT_SYMBOL_GPL(__v4l2_async_nf_add_subdev);
662 struct v4l2_async_subdev *
663 __v4l2_async_nf_add_fwnode(struct v4l2_async_notifier *notifier,
664 struct fwnode_handle *fwnode,
665 unsigned int asd_struct_size)
667 struct v4l2_async_subdev *asd;
670 asd = kzalloc(asd_struct_size, GFP_KERNEL);
672 return ERR_PTR(-ENOMEM);
674 asd->match_type = V4L2_ASYNC_MATCH_FWNODE;
675 asd->match.fwnode = fwnode_handle_get(fwnode);
677 ret = __v4l2_async_nf_add_subdev(notifier, asd);
679 fwnode_handle_put(fwnode);
686 EXPORT_SYMBOL_GPL(__v4l2_async_nf_add_fwnode);
688 struct v4l2_async_subdev *
689 __v4l2_async_nf_add_fwnode_remote(struct v4l2_async_notifier *notif,
690 struct fwnode_handle *endpoint,
691 unsigned int asd_struct_size)
693 struct v4l2_async_subdev *asd;
694 struct fwnode_handle *remote;
696 remote = fwnode_graph_get_remote_endpoint(endpoint);
698 return ERR_PTR(-ENOTCONN);
700 asd = __v4l2_async_nf_add_fwnode(notif, remote, asd_struct_size);
702 * Calling __v4l2_async_nf_add_fwnode grabs a refcount,
703 * so drop the one we got in fwnode_graph_get_remote_port_parent.
705 fwnode_handle_put(remote);
708 EXPORT_SYMBOL_GPL(__v4l2_async_nf_add_fwnode_remote);
710 struct v4l2_async_subdev *
711 __v4l2_async_nf_add_i2c(struct v4l2_async_notifier *notifier, int adapter_id,
712 unsigned short address, unsigned int asd_struct_size)
714 struct v4l2_async_subdev *asd;
717 asd = kzalloc(asd_struct_size, GFP_KERNEL);
719 return ERR_PTR(-ENOMEM);
721 asd->match_type = V4L2_ASYNC_MATCH_I2C;
722 asd->match.i2c.adapter_id = adapter_id;
723 asd->match.i2c.address = address;
725 ret = __v4l2_async_nf_add_subdev(notifier, asd);
733 EXPORT_SYMBOL_GPL(__v4l2_async_nf_add_i2c);
735 int v4l2_async_register_subdev(struct v4l2_subdev *sd)
737 struct v4l2_async_notifier *subdev_notifier;
738 struct v4l2_async_notifier *notifier;
742 * No reference taken. The reference is held by the device
743 * (struct v4l2_subdev.dev), and async sub-device does not
744 * exist independently of the device at any point of time.
746 if (!sd->fwnode && sd->dev)
747 sd->fwnode = dev_fwnode(sd->dev);
749 mutex_lock(&list_lock);
751 INIT_LIST_HEAD(&sd->async_list);
753 list_for_each_entry(notifier, ¬ifier_list, list) {
754 struct v4l2_device *v4l2_dev =
755 v4l2_async_nf_find_v4l2_dev(notifier);
756 struct v4l2_async_subdev *asd;
761 asd = v4l2_async_find_match(notifier, sd);
765 ret = v4l2_async_match_notify(notifier, v4l2_dev, sd, asd);
769 ret = v4l2_async_nf_try_complete(notifier);
776 /* None matched, wait for hot-plugging */
777 list_add(&sd->async_list, &subdev_list);
780 mutex_unlock(&list_lock);
786 * Complete failed. Unbind the sub-devices bound through registering
787 * this async sub-device.
789 subdev_notifier = v4l2_async_find_subdev_notifier(sd);
791 v4l2_async_nf_unbind_all_subdevs(subdev_notifier);
794 v4l2_async_nf_call_unbind(notifier, sd, sd->asd);
795 v4l2_async_cleanup(sd);
797 mutex_unlock(&list_lock);
801 EXPORT_SYMBOL(v4l2_async_register_subdev);
803 void v4l2_async_unregister_subdev(struct v4l2_subdev *sd)
805 if (!sd->async_list.next)
808 mutex_lock(&list_lock);
810 __v4l2_async_nf_unregister(sd->subdev_notifier);
811 __v4l2_async_nf_cleanup(sd->subdev_notifier);
812 kfree(sd->subdev_notifier);
813 sd->subdev_notifier = NULL;
816 struct v4l2_async_notifier *notifier = sd->notifier;
818 list_add(&sd->asd->list, ¬ifier->waiting);
820 v4l2_async_nf_call_unbind(notifier, sd, sd->asd);
823 v4l2_async_cleanup(sd);
825 mutex_unlock(&list_lock);
827 EXPORT_SYMBOL(v4l2_async_unregister_subdev);
829 static void print_waiting_subdev(struct seq_file *s,
830 struct v4l2_async_subdev *asd)
832 switch (asd->match_type) {
833 case V4L2_ASYNC_MATCH_I2C:
834 seq_printf(s, " [i2c] dev=%d-%04x\n", asd->match.i2c.adapter_id,
835 asd->match.i2c.address);
837 case V4L2_ASYNC_MATCH_FWNODE: {
838 struct fwnode_handle *devnode, *fwnode = asd->match.fwnode;
840 devnode = fwnode_graph_is_endpoint(fwnode) ?
841 fwnode_graph_get_port_parent(fwnode) :
842 fwnode_handle_get(fwnode);
844 seq_printf(s, " [fwnode] dev=%s, node=%pfw\n",
845 devnode->dev ? dev_name(devnode->dev) : "nil",
848 fwnode_handle_put(devnode);
855 v4l2_async_nf_name(struct v4l2_async_notifier *notifier)
857 if (notifier->v4l2_dev)
858 return notifier->v4l2_dev->name;
859 else if (notifier->sd)
860 return notifier->sd->name;
865 static int pending_subdevs_show(struct seq_file *s, void *data)
867 struct v4l2_async_notifier *notif;
868 struct v4l2_async_subdev *asd;
870 mutex_lock(&list_lock);
872 list_for_each_entry(notif, ¬ifier_list, list) {
873 seq_printf(s, "%s:\n", v4l2_async_nf_name(notif));
874 list_for_each_entry(asd, ¬if->waiting, list)
875 print_waiting_subdev(s, asd);
878 mutex_unlock(&list_lock);
882 DEFINE_SHOW_ATTRIBUTE(pending_subdevs);
884 static struct dentry *v4l2_async_debugfs_dir;
886 static int __init v4l2_async_init(void)
888 v4l2_async_debugfs_dir = debugfs_create_dir("v4l2-async", NULL);
889 debugfs_create_file("pending_async_subdevices", 0444,
890 v4l2_async_debugfs_dir, NULL,
891 &pending_subdevs_fops);
896 static void __exit v4l2_async_exit(void)
898 debugfs_remove_recursive(v4l2_async_debugfs_dir);
901 subsys_initcall(v4l2_async_init);
902 module_exit(v4l2_async_exit);
904 MODULE_AUTHOR("Guennadi Liakhovetski <g.liakhovetski@gmx.de>");
905 MODULE_AUTHOR("Sakari Ailus <sakari.ailus@linux.intel.com>");
906 MODULE_AUTHOR("Ezequiel Garcia <ezequiel@collabora.com>");
907 MODULE_LICENSE("GPL");