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 void v4l2_async_nf_call_destroy(struct v4l2_async_notifier *n,
56 struct v4l2_async_subdev *asd)
58 if (!n->ops || !n->ops->destroy)
64 static bool match_i2c(struct v4l2_async_notifier *notifier,
65 struct v4l2_subdev *sd, struct v4l2_async_subdev *asd)
67 #if IS_ENABLED(CONFIG_I2C)
68 struct i2c_client *client = i2c_verify_client(sd->dev);
71 asd->match.i2c.adapter_id == client->adapter->nr &&
72 asd->match.i2c.address == client->addr;
79 match_fwnode_one(struct v4l2_async_notifier *notifier,
80 struct v4l2_subdev *sd, struct fwnode_handle *sd_fwnode,
81 struct v4l2_async_subdev *asd)
83 struct fwnode_handle *other_fwnode;
84 struct fwnode_handle *dev_fwnode;
85 bool asd_fwnode_is_ep;
90 * Both the subdev and the async subdev can provide either an endpoint
91 * fwnode or a device fwnode. Start with the simple case of direct
94 if (sd_fwnode == asd->match.fwnode)
98 * Otherwise, check if the sd fwnode and the asd fwnode refer to an
99 * endpoint or a device. If they're of the same type, there's no match.
100 * Technically speaking this checks if the nodes refer to a connected
101 * endpoint, which is the simplest check that works for both OF and
102 * ACPI. This won't make a difference, as drivers should not try to
103 * match unconnected endpoints.
105 sd_fwnode_is_ep = fwnode_graph_is_endpoint(sd_fwnode);
106 asd_fwnode_is_ep = fwnode_graph_is_endpoint(asd->match.fwnode);
108 if (sd_fwnode_is_ep == asd_fwnode_is_ep)
112 * The sd and asd fwnodes are of different types. Get the device fwnode
113 * parent of the endpoint fwnode, and compare it with the other fwnode.
115 if (sd_fwnode_is_ep) {
116 dev_fwnode = fwnode_graph_get_port_parent(sd_fwnode);
117 other_fwnode = asd->match.fwnode;
119 dev_fwnode = fwnode_graph_get_port_parent(asd->match.fwnode);
120 other_fwnode = sd_fwnode;
123 fwnode_handle_put(dev_fwnode);
125 if (dev_fwnode != other_fwnode)
129 * We have a heterogeneous match. Retrieve the struct device of the side
130 * that matched on a device fwnode to print its driver name.
133 dev = notifier->v4l2_dev ? notifier->v4l2_dev->dev
138 if (dev && dev->driver) {
140 dev_warn(dev, "Driver %s uses device fwnode, incorrect match may occur\n",
142 dev_notice(dev, "Consider updating driver %s to match on endpoints\n",
149 static bool match_fwnode(struct v4l2_async_notifier *notifier,
150 struct v4l2_subdev *sd, struct v4l2_async_subdev *asd)
152 if (match_fwnode_one(notifier, sd, sd->fwnode, asd))
155 /* Also check the secondary fwnode. */
156 if (IS_ERR_OR_NULL(sd->fwnode->secondary))
159 return match_fwnode_one(notifier, sd, sd->fwnode->secondary, asd);
162 static LIST_HEAD(subdev_list);
163 static LIST_HEAD(notifier_list);
164 static DEFINE_MUTEX(list_lock);
166 static struct v4l2_async_subdev *
167 v4l2_async_find_match(struct v4l2_async_notifier *notifier,
168 struct v4l2_subdev *sd)
170 bool (*match)(struct v4l2_async_notifier *notifier,
171 struct v4l2_subdev *sd, struct v4l2_async_subdev *asd);
172 struct v4l2_async_subdev *asd;
174 list_for_each_entry(asd, ¬ifier->waiting, list) {
175 /* bus_type has been verified valid before */
176 switch (asd->match_type) {
177 case V4L2_ASYNC_MATCH_I2C:
180 case V4L2_ASYNC_MATCH_FWNODE:
181 match = match_fwnode;
184 /* Cannot happen, unless someone breaks us */
189 /* match cannot be NULL here */
190 if (match(notifier, sd, asd))
197 /* Compare two async sub-device descriptors for equivalence */
198 static bool asd_equal(struct v4l2_async_subdev *asd_x,
199 struct v4l2_async_subdev *asd_y)
201 if (asd_x->match_type != asd_y->match_type)
204 switch (asd_x->match_type) {
205 case V4L2_ASYNC_MATCH_I2C:
206 return asd_x->match.i2c.adapter_id ==
207 asd_y->match.i2c.adapter_id &&
208 asd_x->match.i2c.address ==
209 asd_y->match.i2c.address;
210 case V4L2_ASYNC_MATCH_FWNODE:
211 return asd_x->match.fwnode == asd_y->match.fwnode;
219 /* Find the sub-device notifier registered by a sub-device driver. */
220 static struct v4l2_async_notifier *
221 v4l2_async_find_subdev_notifier(struct v4l2_subdev *sd)
223 struct v4l2_async_notifier *n;
225 list_for_each_entry(n, ¬ifier_list, list)
232 /* Get v4l2_device related to the notifier if one can be found. */
233 static struct v4l2_device *
234 v4l2_async_nf_find_v4l2_dev(struct v4l2_async_notifier *notifier)
236 while (notifier->parent)
237 notifier = notifier->parent;
239 return notifier->v4l2_dev;
243 * Return true if all child sub-device notifiers are complete, false otherwise.
246 v4l2_async_nf_can_complete(struct v4l2_async_notifier *notifier)
248 struct v4l2_subdev *sd;
250 if (!list_empty(¬ifier->waiting))
253 list_for_each_entry(sd, ¬ifier->done, async_list) {
254 struct v4l2_async_notifier *subdev_notifier =
255 v4l2_async_find_subdev_notifier(sd);
257 if (subdev_notifier &&
258 !v4l2_async_nf_can_complete(subdev_notifier))
266 * Complete the master notifier if possible. This is done when all async
267 * sub-devices have been bound; v4l2_device is also available then.
270 v4l2_async_nf_try_complete(struct v4l2_async_notifier *notifier)
272 /* Quick check whether there are still more sub-devices here. */
273 if (!list_empty(¬ifier->waiting))
276 /* Check the entire notifier tree; find the root notifier first. */
277 while (notifier->parent)
278 notifier = notifier->parent;
280 /* This is root if it has v4l2_dev. */
281 if (!notifier->v4l2_dev)
284 /* Is everything ready? */
285 if (!v4l2_async_nf_can_complete(notifier))
288 return v4l2_async_nf_call_complete(notifier);
292 v4l2_async_nf_try_all_subdevs(struct v4l2_async_notifier *notifier);
294 static int v4l2_async_create_ancillary_links(struct v4l2_async_notifier *n,
295 struct v4l2_subdev *sd)
297 struct media_link *link = NULL;
299 #if IS_ENABLED(CONFIG_MEDIA_CONTROLLER)
301 if (sd->entity.function != MEDIA_ENT_F_LENS &&
302 sd->entity.function != MEDIA_ENT_F_FLASH)
305 link = media_create_ancillary_link(&n->sd->entity, &sd->entity);
309 return IS_ERR(link) ? PTR_ERR(link) : 0;
312 static int v4l2_async_match_notify(struct v4l2_async_notifier *notifier,
313 struct v4l2_device *v4l2_dev,
314 struct v4l2_subdev *sd,
315 struct v4l2_async_subdev *asd)
317 struct v4l2_async_notifier *subdev_notifier;
320 ret = v4l2_device_register_subdev(v4l2_dev, sd);
324 ret = v4l2_async_nf_call_bound(notifier, sd, asd);
326 v4l2_device_unregister_subdev(sd);
331 * Depending of the function of the entities involved, we may want to
332 * create links between them (for example between a sensor and its lens
333 * or between a sensor's source pad and the connected device's sink
336 ret = v4l2_async_create_ancillary_links(notifier, sd);
338 v4l2_async_nf_call_unbind(notifier, sd, asd);
339 v4l2_device_unregister_subdev(sd);
343 /* Remove from the waiting list */
344 list_del(&asd->list);
346 sd->notifier = notifier;
348 /* Move from the global subdevice list to notifier's done */
349 list_move(&sd->async_list, ¬ifier->done);
352 * See if the sub-device has a notifier. If not, return here.
354 subdev_notifier = v4l2_async_find_subdev_notifier(sd);
355 if (!subdev_notifier || subdev_notifier->parent)
359 * Proceed with checking for the sub-device notifier's async
360 * sub-devices, and return the result. The error will be handled by the
363 subdev_notifier->parent = notifier;
365 return v4l2_async_nf_try_all_subdevs(subdev_notifier);
368 /* Test all async sub-devices in a notifier for a match. */
370 v4l2_async_nf_try_all_subdevs(struct v4l2_async_notifier *notifier)
372 struct v4l2_device *v4l2_dev =
373 v4l2_async_nf_find_v4l2_dev(notifier);
374 struct v4l2_subdev *sd;
380 list_for_each_entry(sd, &subdev_list, async_list) {
381 struct v4l2_async_subdev *asd;
384 asd = v4l2_async_find_match(notifier, sd);
388 ret = v4l2_async_match_notify(notifier, v4l2_dev, sd, asd);
393 * v4l2_async_match_notify() may lead to registering a
394 * new notifier and thus changing the async subdevs
395 * list. In order to proceed safely from here, restart
396 * parsing the list from the beginning.
404 static void v4l2_async_cleanup(struct v4l2_subdev *sd)
406 v4l2_device_unregister_subdev(sd);
408 * Subdevice driver will reprobe and put the subdev back
411 list_del_init(&sd->async_list);
415 /* Unbind all sub-devices in the notifier tree. */
417 v4l2_async_nf_unbind_all_subdevs(struct v4l2_async_notifier *notifier)
419 struct v4l2_subdev *sd, *tmp;
421 list_for_each_entry_safe(sd, tmp, ¬ifier->done, async_list) {
422 struct v4l2_async_notifier *subdev_notifier =
423 v4l2_async_find_subdev_notifier(sd);
426 v4l2_async_nf_unbind_all_subdevs(subdev_notifier);
428 v4l2_async_nf_call_unbind(notifier, sd, sd->asd);
429 v4l2_async_cleanup(sd);
431 list_move(&sd->async_list, &subdev_list);
434 notifier->parent = NULL;
437 /* See if an async sub-device can be found in a notifier's lists. */
439 __v4l2_async_nf_has_async_subdev(struct v4l2_async_notifier *notifier,
440 struct v4l2_async_subdev *asd)
442 struct v4l2_async_subdev *asd_y;
443 struct v4l2_subdev *sd;
445 list_for_each_entry(asd_y, ¬ifier->waiting, list)
446 if (asd_equal(asd, asd_y))
449 list_for_each_entry(sd, ¬ifier->done, async_list) {
450 if (WARN_ON(!sd->asd))
453 if (asd_equal(asd, sd->asd))
461 * Find out whether an async sub-device was set up already or
462 * whether it exists in a given notifier before @this_index.
463 * If @this_index < 0, search the notifier's entire @asd_list.
466 v4l2_async_nf_has_async_subdev(struct v4l2_async_notifier *notifier,
467 struct v4l2_async_subdev *asd, int this_index)
469 struct v4l2_async_subdev *asd_y;
472 lockdep_assert_held(&list_lock);
474 /* Check that an asd is not being added more than once. */
475 list_for_each_entry(asd_y, ¬ifier->asd_list, asd_list) {
476 if (this_index >= 0 && j++ >= this_index)
478 if (asd_equal(asd, asd_y))
482 /* Check that an asd does not exist in other notifiers. */
483 list_for_each_entry(notifier, ¬ifier_list, list)
484 if (__v4l2_async_nf_has_async_subdev(notifier, asd))
490 static int v4l2_async_nf_asd_valid(struct v4l2_async_notifier *notifier,
491 struct v4l2_async_subdev *asd,
495 notifier->v4l2_dev ? notifier->v4l2_dev->dev : NULL;
500 switch (asd->match_type) {
501 case V4L2_ASYNC_MATCH_I2C:
502 case V4L2_ASYNC_MATCH_FWNODE:
503 if (v4l2_async_nf_has_async_subdev(notifier, asd, this_index)) {
504 dev_dbg(dev, "subdev descriptor already listed in this or other notifiers\n");
509 dev_err(dev, "Invalid match type %u on %p\n",
510 asd->match_type, asd);
517 void v4l2_async_nf_init(struct v4l2_async_notifier *notifier)
519 INIT_LIST_HEAD(¬ifier->asd_list);
521 EXPORT_SYMBOL(v4l2_async_nf_init);
523 static int __v4l2_async_nf_register(struct v4l2_async_notifier *notifier)
525 struct v4l2_async_subdev *asd;
528 INIT_LIST_HEAD(¬ifier->waiting);
529 INIT_LIST_HEAD(¬ifier->done);
531 mutex_lock(&list_lock);
533 list_for_each_entry(asd, ¬ifier->asd_list, asd_list) {
534 ret = v4l2_async_nf_asd_valid(notifier, asd, i++);
538 list_add_tail(&asd->list, ¬ifier->waiting);
541 ret = v4l2_async_nf_try_all_subdevs(notifier);
545 ret = v4l2_async_nf_try_complete(notifier);
549 /* Keep also completed notifiers on the list */
550 list_add(¬ifier->list, ¬ifier_list);
552 mutex_unlock(&list_lock);
558 * On failure, unbind all sub-devices registered through this notifier.
560 v4l2_async_nf_unbind_all_subdevs(notifier);
563 mutex_unlock(&list_lock);
568 int v4l2_async_nf_register(struct v4l2_device *v4l2_dev,
569 struct v4l2_async_notifier *notifier)
573 if (WARN_ON(!v4l2_dev || notifier->sd))
576 notifier->v4l2_dev = v4l2_dev;
578 ret = __v4l2_async_nf_register(notifier);
580 notifier->v4l2_dev = NULL;
584 EXPORT_SYMBOL(v4l2_async_nf_register);
586 int v4l2_async_subdev_nf_register(struct v4l2_subdev *sd,
587 struct v4l2_async_notifier *notifier)
591 if (WARN_ON(!sd || notifier->v4l2_dev))
596 ret = __v4l2_async_nf_register(notifier);
602 EXPORT_SYMBOL(v4l2_async_subdev_nf_register);
605 __v4l2_async_nf_unregister(struct v4l2_async_notifier *notifier)
607 if (!notifier || (!notifier->v4l2_dev && !notifier->sd))
610 v4l2_async_nf_unbind_all_subdevs(notifier);
613 notifier->v4l2_dev = NULL;
615 list_del(¬ifier->list);
618 void v4l2_async_nf_unregister(struct v4l2_async_notifier *notifier)
620 mutex_lock(&list_lock);
622 __v4l2_async_nf_unregister(notifier);
624 mutex_unlock(&list_lock);
626 EXPORT_SYMBOL(v4l2_async_nf_unregister);
628 static void __v4l2_async_nf_cleanup(struct v4l2_async_notifier *notifier)
630 struct v4l2_async_subdev *asd, *tmp;
632 if (!notifier || !notifier->asd_list.next)
635 list_for_each_entry_safe(asd, tmp, ¬ifier->asd_list, asd_list) {
636 switch (asd->match_type) {
637 case V4L2_ASYNC_MATCH_FWNODE:
638 fwnode_handle_put(asd->match.fwnode);
644 list_del(&asd->asd_list);
645 v4l2_async_nf_call_destroy(notifier, asd);
650 void v4l2_async_nf_cleanup(struct v4l2_async_notifier *notifier)
652 mutex_lock(&list_lock);
654 __v4l2_async_nf_cleanup(notifier);
656 mutex_unlock(&list_lock);
658 EXPORT_SYMBOL_GPL(v4l2_async_nf_cleanup);
660 int __v4l2_async_nf_add_subdev(struct v4l2_async_notifier *notifier,
661 struct v4l2_async_subdev *asd)
665 mutex_lock(&list_lock);
667 ret = v4l2_async_nf_asd_valid(notifier, asd, -1);
671 list_add_tail(&asd->asd_list, ¬ifier->asd_list);
674 mutex_unlock(&list_lock);
677 EXPORT_SYMBOL_GPL(__v4l2_async_nf_add_subdev);
679 struct v4l2_async_subdev *
680 __v4l2_async_nf_add_fwnode(struct v4l2_async_notifier *notifier,
681 struct fwnode_handle *fwnode,
682 unsigned int asd_struct_size)
684 struct v4l2_async_subdev *asd;
687 asd = kzalloc(asd_struct_size, GFP_KERNEL);
689 return ERR_PTR(-ENOMEM);
691 asd->match_type = V4L2_ASYNC_MATCH_FWNODE;
692 asd->match.fwnode = fwnode_handle_get(fwnode);
694 ret = __v4l2_async_nf_add_subdev(notifier, asd);
696 fwnode_handle_put(fwnode);
703 EXPORT_SYMBOL_GPL(__v4l2_async_nf_add_fwnode);
705 struct v4l2_async_subdev *
706 __v4l2_async_nf_add_fwnode_remote(struct v4l2_async_notifier *notif,
707 struct fwnode_handle *endpoint,
708 unsigned int asd_struct_size)
710 struct v4l2_async_subdev *asd;
711 struct fwnode_handle *remote;
713 remote = fwnode_graph_get_remote_endpoint(endpoint);
715 return ERR_PTR(-ENOTCONN);
717 asd = __v4l2_async_nf_add_fwnode(notif, remote, asd_struct_size);
719 * Calling __v4l2_async_nf_add_fwnode grabs a refcount,
720 * so drop the one we got in fwnode_graph_get_remote_port_parent.
722 fwnode_handle_put(remote);
725 EXPORT_SYMBOL_GPL(__v4l2_async_nf_add_fwnode_remote);
727 struct v4l2_async_subdev *
728 __v4l2_async_nf_add_i2c(struct v4l2_async_notifier *notifier, int adapter_id,
729 unsigned short address, unsigned int asd_struct_size)
731 struct v4l2_async_subdev *asd;
734 asd = kzalloc(asd_struct_size, GFP_KERNEL);
736 return ERR_PTR(-ENOMEM);
738 asd->match_type = V4L2_ASYNC_MATCH_I2C;
739 asd->match.i2c.adapter_id = adapter_id;
740 asd->match.i2c.address = address;
742 ret = __v4l2_async_nf_add_subdev(notifier, asd);
750 EXPORT_SYMBOL_GPL(__v4l2_async_nf_add_i2c);
752 int v4l2_async_register_subdev(struct v4l2_subdev *sd)
754 struct v4l2_async_notifier *subdev_notifier;
755 struct v4l2_async_notifier *notifier;
759 * No reference taken. The reference is held by the device
760 * (struct v4l2_subdev.dev), and async sub-device does not
761 * exist independently of the device at any point of time.
763 if (!sd->fwnode && sd->dev)
764 sd->fwnode = dev_fwnode(sd->dev);
766 mutex_lock(&list_lock);
768 INIT_LIST_HEAD(&sd->async_list);
770 list_for_each_entry(notifier, ¬ifier_list, list) {
771 struct v4l2_device *v4l2_dev =
772 v4l2_async_nf_find_v4l2_dev(notifier);
773 struct v4l2_async_subdev *asd;
778 asd = v4l2_async_find_match(notifier, sd);
782 ret = v4l2_async_match_notify(notifier, v4l2_dev, sd, asd);
786 ret = v4l2_async_nf_try_complete(notifier);
793 /* None matched, wait for hot-plugging */
794 list_add(&sd->async_list, &subdev_list);
797 mutex_unlock(&list_lock);
803 * Complete failed. Unbind the sub-devices bound through registering
804 * this async sub-device.
806 subdev_notifier = v4l2_async_find_subdev_notifier(sd);
808 v4l2_async_nf_unbind_all_subdevs(subdev_notifier);
811 v4l2_async_nf_call_unbind(notifier, sd, sd->asd);
812 v4l2_async_cleanup(sd);
814 mutex_unlock(&list_lock);
818 EXPORT_SYMBOL(v4l2_async_register_subdev);
820 void v4l2_async_unregister_subdev(struct v4l2_subdev *sd)
822 if (!sd->async_list.next)
825 mutex_lock(&list_lock);
827 __v4l2_async_nf_unregister(sd->subdev_notifier);
828 __v4l2_async_nf_cleanup(sd->subdev_notifier);
829 kfree(sd->subdev_notifier);
830 sd->subdev_notifier = NULL;
833 struct v4l2_async_notifier *notifier = sd->notifier;
835 list_add(&sd->asd->list, ¬ifier->waiting);
837 v4l2_async_nf_call_unbind(notifier, sd, sd->asd);
840 v4l2_async_cleanup(sd);
842 mutex_unlock(&list_lock);
844 EXPORT_SYMBOL(v4l2_async_unregister_subdev);
846 static void print_waiting_subdev(struct seq_file *s,
847 struct v4l2_async_subdev *asd)
849 switch (asd->match_type) {
850 case V4L2_ASYNC_MATCH_I2C:
851 seq_printf(s, " [i2c] dev=%d-%04x\n", asd->match.i2c.adapter_id,
852 asd->match.i2c.address);
854 case V4L2_ASYNC_MATCH_FWNODE: {
855 struct fwnode_handle *devnode, *fwnode = asd->match.fwnode;
857 devnode = fwnode_graph_is_endpoint(fwnode) ?
858 fwnode_graph_get_port_parent(fwnode) :
859 fwnode_handle_get(fwnode);
861 seq_printf(s, " [fwnode] dev=%s, node=%pfw\n",
862 devnode->dev ? dev_name(devnode->dev) : "nil",
865 fwnode_handle_put(devnode);
872 v4l2_async_nf_name(struct v4l2_async_notifier *notifier)
874 if (notifier->v4l2_dev)
875 return notifier->v4l2_dev->name;
876 else if (notifier->sd)
877 return notifier->sd->name;
882 static int pending_subdevs_show(struct seq_file *s, void *data)
884 struct v4l2_async_notifier *notif;
885 struct v4l2_async_subdev *asd;
887 mutex_lock(&list_lock);
889 list_for_each_entry(notif, ¬ifier_list, list) {
890 seq_printf(s, "%s:\n", v4l2_async_nf_name(notif));
891 list_for_each_entry(asd, ¬if->waiting, list)
892 print_waiting_subdev(s, asd);
895 mutex_unlock(&list_lock);
899 DEFINE_SHOW_ATTRIBUTE(pending_subdevs);
901 static struct dentry *v4l2_async_debugfs_dir;
903 static int __init v4l2_async_init(void)
905 v4l2_async_debugfs_dir = debugfs_create_dir("v4l2-async", NULL);
906 debugfs_create_file("pending_async_subdevices", 0444,
907 v4l2_async_debugfs_dir, NULL,
908 &pending_subdevs_fops);
913 static void __exit v4l2_async_exit(void)
915 debugfs_remove_recursive(v4l2_async_debugfs_dir);
918 subsys_initcall(v4l2_async_init);
919 module_exit(v4l2_async_exit);
921 MODULE_AUTHOR("Guennadi Liakhovetski <g.liakhovetski@gmx.de>");
922 MODULE_AUTHOR("Sakari Ailus <sakari.ailus@linux.intel.com>");
923 MODULE_AUTHOR("Ezequiel Garcia <ezequiel@collabora.com>");
924 MODULE_LICENSE("GPL");