2 * V4L2 asynchronous subdevice registration API
4 * Copyright (C) 2012-2013, Guennadi Liakhovetski <g.liakhovetski@gmx.de>
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
11 #include <linux/device.h>
12 #include <linux/err.h>
13 #include <linux/i2c.h>
14 #include <linux/list.h>
15 #include <linux/module.h>
16 #include <linux/mutex.h>
17 #include <linux/platform_device.h>
18 #include <linux/slab.h>
19 #include <linux/types.h>
21 #include <media/v4l2-async.h>
22 #include <media/v4l2-device.h>
23 #include <media/v4l2-subdev.h>
25 static bool match_i2c(struct device *dev, struct v4l2_async_subdev *asd)
27 #if IS_ENABLED(CONFIG_I2C)
28 struct i2c_client *client = i2c_verify_client(dev);
30 asd->match.i2c.adapter_id == client->adapter->nr &&
31 asd->match.i2c.address == client->addr;
37 static bool match_devname(struct device *dev, struct v4l2_async_subdev *asd)
39 return !strcmp(asd->match.device_name.name, dev_name(dev));
42 static bool match_of(struct device *dev, struct v4l2_async_subdev *asd)
44 return dev->of_node == asd->match.of.node;
47 static LIST_HEAD(subdev_list);
48 static LIST_HEAD(notifier_list);
49 static DEFINE_MUTEX(list_lock);
51 static struct v4l2_async_subdev *v4l2_async_belongs(struct v4l2_async_notifier *notifier,
52 struct v4l2_subdev *sd)
54 struct v4l2_async_subdev *asd;
55 bool (*match)(struct device *, struct v4l2_async_subdev *);
57 list_for_each_entry(asd, ¬ifier->waiting, list) {
58 /* bus_type has been verified valid before */
59 switch (asd->match_type) {
60 case V4L2_ASYNC_MATCH_CUSTOM:
61 match = asd->match.custom.match;
66 case V4L2_ASYNC_MATCH_DEVNAME:
67 match = match_devname;
69 case V4L2_ASYNC_MATCH_I2C:
72 case V4L2_ASYNC_MATCH_OF:
76 /* Cannot happen, unless someone breaks us */
81 /* match cannot be NULL here */
82 if (match(sd->dev, asd))
89 static int v4l2_async_test_notify(struct v4l2_async_notifier *notifier,
90 struct v4l2_subdev *sd,
91 struct v4l2_async_subdev *asd)
95 /* Remove from the waiting list */
98 sd->notifier = notifier;
100 if (notifier->bound) {
101 ret = notifier->bound(notifier, sd, asd);
105 /* Move from the global subdevice list to notifier's done */
106 list_move(&sd->async_list, ¬ifier->done);
108 ret = v4l2_device_register_subdev(notifier->v4l2_dev, sd);
110 if (notifier->unbind)
111 notifier->unbind(notifier, sd, asd);
115 if (list_empty(¬ifier->waiting) && notifier->complete)
116 return notifier->complete(notifier);
121 static void v4l2_async_cleanup(struct v4l2_subdev *sd)
123 v4l2_device_unregister_subdev(sd);
124 /* Subdevice driver will reprobe and put the subdev back onto the list */
125 list_del_init(&sd->async_list);
130 int v4l2_async_notifier_register(struct v4l2_device *v4l2_dev,
131 struct v4l2_async_notifier *notifier)
133 struct v4l2_subdev *sd, *tmp;
134 struct v4l2_async_subdev *asd;
137 if (!notifier->num_subdevs || notifier->num_subdevs > V4L2_MAX_SUBDEVS)
140 notifier->v4l2_dev = v4l2_dev;
141 INIT_LIST_HEAD(¬ifier->waiting);
142 INIT_LIST_HEAD(¬ifier->done);
144 for (i = 0; i < notifier->num_subdevs; i++) {
145 asd = notifier->subdevs[i];
147 switch (asd->match_type) {
148 case V4L2_ASYNC_MATCH_CUSTOM:
149 case V4L2_ASYNC_MATCH_DEVNAME:
150 case V4L2_ASYNC_MATCH_I2C:
151 case V4L2_ASYNC_MATCH_OF:
154 dev_err(notifier->v4l2_dev ? notifier->v4l2_dev->dev : NULL,
155 "Invalid match type %u on %p\n",
156 asd->match_type, asd);
159 list_add_tail(&asd->list, ¬ifier->waiting);
162 mutex_lock(&list_lock);
164 /* Keep also completed notifiers on the list */
165 list_add(¬ifier->list, ¬ifier_list);
167 list_for_each_entry_safe(sd, tmp, &subdev_list, async_list) {
170 asd = v4l2_async_belongs(notifier, sd);
174 ret = v4l2_async_test_notify(notifier, sd, asd);
176 mutex_unlock(&list_lock);
181 mutex_unlock(&list_lock);
185 EXPORT_SYMBOL(v4l2_async_notifier_register);
187 void v4l2_async_notifier_unregister(struct v4l2_async_notifier *notifier)
189 struct v4l2_subdev *sd, *tmp;
190 unsigned int notif_n_subdev = notifier->num_subdevs;
191 unsigned int n_subdev = min(notif_n_subdev, V4L2_MAX_SUBDEVS);
195 if (!notifier->v4l2_dev)
198 dev = kmalloc(n_subdev * sizeof(*dev), GFP_KERNEL);
200 dev_err(notifier->v4l2_dev->dev,
201 "Failed to allocate device cache!\n");
204 mutex_lock(&list_lock);
206 list_del(¬ifier->list);
208 list_for_each_entry_safe(sd, tmp, ¬ifier->done, async_list) {
211 d = get_device(sd->dev);
213 v4l2_async_cleanup(sd);
215 /* If we handled USB devices, we'd have to lock the parent too */
216 device_release_driver(d);
218 if (notifier->unbind)
219 notifier->unbind(notifier, sd, sd->asd);
222 * Store device at the device cache, in order to call
223 * put_device() on the final step
231 mutex_unlock(&list_lock);
234 * Call device_attach() to reprobe devices
236 * NOTE: If dev allocation fails, i is 0, and the whole loop won't be
240 struct device *d = dev[i];
242 if (d && device_attach(d) < 0) {
243 const char *name = "(none)";
244 int lock = device_trylock(d);
246 if (lock && d->driver)
247 name = d->driver->name;
248 dev_err(d, "Failed to re-probe to %s\n", name);
256 notifier->v4l2_dev = NULL;
259 * Don't care about the waiting list, it is initialised and populated
260 * upon notifier registration.
263 EXPORT_SYMBOL(v4l2_async_notifier_unregister);
265 int v4l2_async_register_subdev(struct v4l2_subdev *sd)
267 struct v4l2_async_notifier *notifier;
269 mutex_lock(&list_lock);
271 INIT_LIST_HEAD(&sd->async_list);
273 list_for_each_entry(notifier, ¬ifier_list, list) {
274 struct v4l2_async_subdev *asd = v4l2_async_belongs(notifier, sd);
276 int ret = v4l2_async_test_notify(notifier, sd, asd);
277 mutex_unlock(&list_lock);
282 /* None matched, wait for hot-plugging */
283 list_add(&sd->async_list, &subdev_list);
285 mutex_unlock(&list_lock);
289 EXPORT_SYMBOL(v4l2_async_register_subdev);
291 void v4l2_async_unregister_subdev(struct v4l2_subdev *sd)
293 struct v4l2_async_notifier *notifier = sd->notifier;
296 if (!list_empty(&sd->async_list))
297 v4l2_async_cleanup(sd);
301 mutex_lock(&list_lock);
303 list_add(&sd->asd->list, ¬ifier->waiting);
305 v4l2_async_cleanup(sd);
307 if (notifier->unbind)
308 notifier->unbind(notifier, sd, sd->asd);
310 mutex_unlock(&list_lock);
312 EXPORT_SYMBOL(v4l2_async_unregister_subdev);