1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 V4L2 device support.
4
5 Copyright (C) 2008 Hans Verkuil <hverkuil@xs4all.nl>
6
7 */
8
9 #include <linux/types.h>
10 #include <linux/ioctl.h>
11 #include <linux/module.h>
12 #include <linux/slab.h>
13 #include <linux/videodev2.h>
14 #include <media/v4l2-device.h>
15 #include <media/v4l2-ctrls.h>
16
v4l2_device_register(struct device * dev,struct v4l2_device * v4l2_dev)17 int v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev)
18 {
19 if (v4l2_dev == NULL)
20 return -EINVAL;
21
22 INIT_LIST_HEAD(&v4l2_dev->subdevs);
23 spin_lock_init(&v4l2_dev->lock);
24 v4l2_prio_init(&v4l2_dev->prio);
25 kref_init(&v4l2_dev->ref);
26 get_device(dev);
27 v4l2_dev->dev = dev;
28 if (dev == NULL) {
29 /* If dev == NULL, then name must be filled in by the caller */
30 if (WARN_ON(!v4l2_dev->name[0]))
31 return -EINVAL;
32 return 0;
33 }
34
35 /* Set name to driver name + device name if it is empty. */
36 if (!v4l2_dev->name[0])
37 snprintf(v4l2_dev->name, sizeof(v4l2_dev->name), "%s %s",
38 dev->driver->name, dev_name(dev));
39 if (!dev_get_drvdata(dev))
40 dev_set_drvdata(dev, v4l2_dev);
41 return 0;
42 }
43 EXPORT_SYMBOL_GPL(v4l2_device_register);
44
v4l2_device_release(struct kref * ref)45 static void v4l2_device_release(struct kref *ref)
46 {
47 struct v4l2_device *v4l2_dev =
48 container_of(ref, struct v4l2_device, ref);
49
50 if (v4l2_dev->release)
51 v4l2_dev->release(v4l2_dev);
52 }
53
v4l2_device_put(struct v4l2_device * v4l2_dev)54 int v4l2_device_put(struct v4l2_device *v4l2_dev)
55 {
56 return kref_put(&v4l2_dev->ref, v4l2_device_release);
57 }
58 EXPORT_SYMBOL_GPL(v4l2_device_put);
59
v4l2_device_set_name(struct v4l2_device * v4l2_dev,const char * basename,atomic_t * instance)60 int v4l2_device_set_name(struct v4l2_device *v4l2_dev, const char *basename,
61 atomic_t *instance)
62 {
63 int num = atomic_inc_return(instance) - 1;
64 int len = strlen(basename);
65
66 if (basename[len - 1] >= '0' && basename[len - 1] <= '9')
67 snprintf(v4l2_dev->name, sizeof(v4l2_dev->name),
68 "%s-%d", basename, num);
69 else
70 snprintf(v4l2_dev->name, sizeof(v4l2_dev->name),
71 "%s%d", basename, num);
72 return num;
73 }
74 EXPORT_SYMBOL_GPL(v4l2_device_set_name);
75
v4l2_device_disconnect(struct v4l2_device * v4l2_dev)76 void v4l2_device_disconnect(struct v4l2_device *v4l2_dev)
77 {
78 if (v4l2_dev->dev == NULL)
79 return;
80
81 if (dev_get_drvdata(v4l2_dev->dev) == v4l2_dev)
82 dev_set_drvdata(v4l2_dev->dev, NULL);
83 put_device(v4l2_dev->dev);
84 v4l2_dev->dev = NULL;
85 }
86 EXPORT_SYMBOL_GPL(v4l2_device_disconnect);
87
v4l2_device_unregister(struct v4l2_device * v4l2_dev)88 void v4l2_device_unregister(struct v4l2_device *v4l2_dev)
89 {
90 struct v4l2_subdev *sd, *next;
91
92 /* Just return if v4l2_dev is NULL or if it was already
93 * unregistered before. */
94 if (v4l2_dev == NULL || !v4l2_dev->name[0])
95 return;
96 v4l2_device_disconnect(v4l2_dev);
97
98 /* Unregister subdevs */
99 list_for_each_entry_safe(sd, next, &v4l2_dev->subdevs, list) {
100 v4l2_device_unregister_subdev(sd);
101 if (sd->flags & V4L2_SUBDEV_FL_IS_I2C)
102 v4l2_i2c_subdev_unregister(sd);
103 else if (sd->flags & V4L2_SUBDEV_FL_IS_SPI)
104 v4l2_spi_subdev_unregister(sd);
105 }
106 /* Mark as unregistered, thus preventing duplicate unregistrations */
107 v4l2_dev->name[0] = '\0';
108 }
109 EXPORT_SYMBOL_GPL(v4l2_device_unregister);
110
__v4l2_device_register_subdev(struct v4l2_device * v4l2_dev,struct v4l2_subdev * sd,struct module * module)111 int __v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
112 struct v4l2_subdev *sd, struct module *module)
113 {
114 int err;
115
116 /* Check for valid input */
117 if (!v4l2_dev || !sd || sd->v4l2_dev || !sd->name[0])
118 return -EINVAL;
119
120 /*
121 * The reason to acquire the module here is to avoid unloading
122 * a module of sub-device which is registered to a media
123 * device. To make it possible to unload modules for media
124 * devices that also register sub-devices, do not
125 * try_module_get() such sub-device owners.
126 */
127 sd->owner_v4l2_dev = v4l2_dev->dev && v4l2_dev->dev->driver &&
128 module == v4l2_dev->dev->driver->owner;
129
130 if (!sd->owner_v4l2_dev && !try_module_get(module))
131 return -ENODEV;
132
133 sd->v4l2_dev = v4l2_dev;
134 /* This just returns 0 if either of the two args is NULL */
135 err = v4l2_ctrl_add_handler(v4l2_dev->ctrl_handler, sd->ctrl_handler,
136 NULL, true);
137 if (err)
138 goto error_module;
139
140 #if defined(CONFIG_MEDIA_CONTROLLER)
141 /* Register the entity. */
142 if (v4l2_dev->mdev) {
143 err = media_device_register_entity(v4l2_dev->mdev, &sd->entity);
144 if (err < 0)
145 goto error_module;
146 }
147 #endif
148
149 if (sd->internal_ops && sd->internal_ops->registered) {
150 err = sd->internal_ops->registered(sd);
151 if (err)
152 goto error_unregister;
153 }
154
155 sd->owner = module;
156
157 spin_lock(&v4l2_dev->lock);
158 list_add_tail(&sd->list, &v4l2_dev->subdevs);
159 spin_unlock(&v4l2_dev->lock);
160
161 return 0;
162
163 error_unregister:
164 #if defined(CONFIG_MEDIA_CONTROLLER)
165 media_device_unregister_entity(&sd->entity);
166 #endif
167 error_module:
168 if (!sd->owner_v4l2_dev)
169 module_put(sd->owner);
170 sd->v4l2_dev = NULL;
171 return err;
172 }
173 EXPORT_SYMBOL_GPL(__v4l2_device_register_subdev);
174
v4l2_subdev_release(struct v4l2_subdev * sd)175 static void v4l2_subdev_release(struct v4l2_subdev *sd)
176 {
177 struct module *owner = !sd->owner_v4l2_dev ? sd->owner : NULL;
178
179 if (sd->internal_ops && sd->internal_ops->release)
180 sd->internal_ops->release(sd);
181 sd->devnode = NULL;
182 module_put(owner);
183 }
184
v4l2_device_release_subdev_node(struct video_device * vdev)185 static void v4l2_device_release_subdev_node(struct video_device *vdev)
186 {
187 v4l2_subdev_release(video_get_drvdata(vdev));
188 kfree(vdev);
189 }
190
__v4l2_device_register_subdev_nodes(struct v4l2_device * v4l2_dev,bool read_only)191 int __v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev,
192 bool read_only)
193 {
194 struct video_device *vdev;
195 struct v4l2_subdev *sd;
196 int err;
197
198 /* Register a device node for every subdev marked with the
199 * V4L2_SUBDEV_FL_HAS_DEVNODE flag.
200 */
201 list_for_each_entry(sd, &v4l2_dev->subdevs, list) {
202 if (!(sd->flags & V4L2_SUBDEV_FL_HAS_DEVNODE))
203 continue;
204
205 if (sd->devnode)
206 continue;
207
208 vdev = kzalloc(sizeof(*vdev), GFP_KERNEL);
209 if (!vdev) {
210 err = -ENOMEM;
211 goto clean_up;
212 }
213
214 video_set_drvdata(vdev, sd);
215 strscpy(vdev->name, sd->name, sizeof(vdev->name));
216 vdev->dev_parent = sd->dev;
217 vdev->v4l2_dev = v4l2_dev;
218 vdev->fops = &v4l2_subdev_fops;
219 vdev->release = v4l2_device_release_subdev_node;
220 vdev->ctrl_handler = sd->ctrl_handler;
221 if (read_only)
222 set_bit(V4L2_FL_SUBDEV_RO_DEVNODE, &vdev->flags);
223 sd->devnode = vdev;
224 err = __video_register_device(vdev, VFL_TYPE_SUBDEV, -1, 1,
225 sd->owner);
226 if (err < 0) {
227 sd->devnode = NULL;
228 kfree(vdev);
229 goto clean_up;
230 }
231 #if defined(CONFIG_MEDIA_CONTROLLER)
232 sd->entity.info.dev.major = VIDEO_MAJOR;
233 sd->entity.info.dev.minor = vdev->minor;
234
235 /* Interface is created by __video_register_device() */
236 if (vdev->v4l2_dev->mdev) {
237 struct media_link *link;
238
239 link = media_create_intf_link(&sd->entity,
240 &vdev->intf_devnode->intf,
241 MEDIA_LNK_FL_ENABLED |
242 MEDIA_LNK_FL_IMMUTABLE);
243 if (!link) {
244 err = -ENOMEM;
245 goto clean_up;
246 }
247 }
248 #endif
249 }
250 return 0;
251
252 clean_up:
253 list_for_each_entry(sd, &v4l2_dev->subdevs, list) {
254 if (!sd->devnode)
255 break;
256 video_unregister_device(sd->devnode);
257 }
258
259 return err;
260 }
261 EXPORT_SYMBOL_GPL(__v4l2_device_register_subdev_nodes);
262
v4l2_device_unregister_subdev(struct v4l2_subdev * sd)263 void v4l2_device_unregister_subdev(struct v4l2_subdev *sd)
264 {
265 struct v4l2_device *v4l2_dev;
266
267 /* return if it isn't registered */
268 if (sd == NULL || sd->v4l2_dev == NULL)
269 return;
270
271 v4l2_dev = sd->v4l2_dev;
272
273 spin_lock(&v4l2_dev->lock);
274 list_del(&sd->list);
275 spin_unlock(&v4l2_dev->lock);
276
277 if (sd->internal_ops && sd->internal_ops->unregistered)
278 sd->internal_ops->unregistered(sd);
279 sd->v4l2_dev = NULL;
280
281 #if defined(CONFIG_MEDIA_CONTROLLER)
282 if (v4l2_dev->mdev) {
283 /*
284 * No need to explicitly remove links, as both pads and
285 * links are removed by the function below, in the right order
286 */
287 media_device_unregister_entity(&sd->entity);
288 }
289 #endif
290 if (sd->devnode)
291 video_unregister_device(sd->devnode);
292 else
293 v4l2_subdev_release(sd);
294 }
295 EXPORT_SYMBOL_GPL(v4l2_device_unregister_subdev);
296