1 /*
2 V4L2 device support.
3
4 Copyright (C) 2008 Hans Verkuil <hverkuil@xs4all.nl>
5
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or
9 (at your option) any later version.
10
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, write to the Free Software
18 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19 */
20
21 #include <linux/types.h>
22 #include <linux/ioctl.h>
23 #include <linux/module.h>
24 #include <linux/i2c.h>
25 #include <linux/slab.h>
26 #if defined(CONFIG_SPI)
27 #include <linux/spi/spi.h>
28 #endif
29 #include <linux/videodev2.h>
30 #include <media/v4l2-device.h>
31 #include <media/v4l2-ctrls.h>
32
v4l2_device_register(struct device * dev,struct v4l2_device * v4l2_dev)33 int v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev)
34 {
35 if (v4l2_dev == NULL)
36 return -EINVAL;
37
38 INIT_LIST_HEAD(&v4l2_dev->subdevs);
39 spin_lock_init(&v4l2_dev->lock);
40 v4l2_prio_init(&v4l2_dev->prio);
41 kref_init(&v4l2_dev->ref);
42 get_device(dev);
43 v4l2_dev->dev = dev;
44 if (dev == NULL) {
45 /* If dev == NULL, then name must be filled in by the caller */
46 if (WARN_ON(!v4l2_dev->name[0]))
47 return -EINVAL;
48 return 0;
49 }
50
51 /* Set name to driver name + device name if it is empty. */
52 if (!v4l2_dev->name[0])
53 snprintf(v4l2_dev->name, sizeof(v4l2_dev->name), "%s %s",
54 dev->driver->name, dev_name(dev));
55 if (!dev_get_drvdata(dev))
56 dev_set_drvdata(dev, v4l2_dev);
57 return 0;
58 }
59 EXPORT_SYMBOL_GPL(v4l2_device_register);
60
v4l2_device_release(struct kref * ref)61 static void v4l2_device_release(struct kref *ref)
62 {
63 struct v4l2_device *v4l2_dev =
64 container_of(ref, struct v4l2_device, ref);
65
66 if (v4l2_dev->release)
67 v4l2_dev->release(v4l2_dev);
68 }
69
v4l2_device_put(struct v4l2_device * v4l2_dev)70 int v4l2_device_put(struct v4l2_device *v4l2_dev)
71 {
72 return kref_put(&v4l2_dev->ref, v4l2_device_release);
73 }
74 EXPORT_SYMBOL_GPL(v4l2_device_put);
75
v4l2_device_set_name(struct v4l2_device * v4l2_dev,const char * basename,atomic_t * instance)76 int v4l2_device_set_name(struct v4l2_device *v4l2_dev, const char *basename,
77 atomic_t *instance)
78 {
79 int num = atomic_inc_return(instance) - 1;
80 int len = strlen(basename);
81
82 if (basename[len - 1] >= '0' && basename[len - 1] <= '9')
83 snprintf(v4l2_dev->name, sizeof(v4l2_dev->name),
84 "%s-%d", basename, num);
85 else
86 snprintf(v4l2_dev->name, sizeof(v4l2_dev->name),
87 "%s%d", basename, num);
88 return num;
89 }
90 EXPORT_SYMBOL_GPL(v4l2_device_set_name);
91
v4l2_device_disconnect(struct v4l2_device * v4l2_dev)92 void v4l2_device_disconnect(struct v4l2_device *v4l2_dev)
93 {
94 if (v4l2_dev->dev == NULL)
95 return;
96
97 if (dev_get_drvdata(v4l2_dev->dev) == v4l2_dev)
98 dev_set_drvdata(v4l2_dev->dev, NULL);
99 put_device(v4l2_dev->dev);
100 v4l2_dev->dev = NULL;
101 }
102 EXPORT_SYMBOL_GPL(v4l2_device_disconnect);
103
v4l2_device_unregister(struct v4l2_device * v4l2_dev)104 void v4l2_device_unregister(struct v4l2_device *v4l2_dev)
105 {
106 struct v4l2_subdev *sd, *next;
107
108 /* Just return if v4l2_dev is NULL or if it was already
109 * unregistered before. */
110 if (v4l2_dev == NULL || !v4l2_dev->name[0])
111 return;
112 v4l2_device_disconnect(v4l2_dev);
113
114 /* Unregister subdevs */
115 list_for_each_entry_safe(sd, next, &v4l2_dev->subdevs, list) {
116 v4l2_device_unregister_subdev(sd);
117 #if IS_ENABLED(CONFIG_I2C)
118 if (sd->flags & V4L2_SUBDEV_FL_IS_I2C) {
119 struct i2c_client *client = v4l2_get_subdevdata(sd);
120
121 /*
122 * We need to unregister the i2c client
123 * explicitly. We cannot rely on
124 * i2c_del_adapter to always unregister
125 * clients for us, since if the i2c bus is a
126 * platform bus, then it is never deleted.
127 *
128 * Device tree or ACPI based devices must not
129 * be unregistered as they have not been
130 * registered by us, and would not be
131 * re-created by just probing the V4L2 driver.
132 */
133 if (client &&
134 !client->dev.of_node && !client->dev.fwnode)
135 i2c_unregister_device(client);
136 continue;
137 }
138 #endif
139 #if defined(CONFIG_SPI)
140 if (sd->flags & V4L2_SUBDEV_FL_IS_SPI) {
141 struct spi_device *spi = v4l2_get_subdevdata(sd);
142
143 if (spi && !spi->dev.of_node && !spi->dev.fwnode)
144 spi_unregister_device(spi);
145 continue;
146 }
147 #endif
148 }
149 /* Mark as unregistered, thus preventing duplicate unregistrations */
150 v4l2_dev->name[0] = '\0';
151 }
152 EXPORT_SYMBOL_GPL(v4l2_device_unregister);
153
v4l2_device_register_subdev(struct v4l2_device * v4l2_dev,struct v4l2_subdev * sd)154 int v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
155 struct v4l2_subdev *sd)
156 {
157 #if defined(CONFIG_MEDIA_CONTROLLER)
158 struct media_entity *entity = &sd->entity;
159 #endif
160 int err;
161
162 /* Check for valid input */
163 if (!v4l2_dev || !sd || sd->v4l2_dev || !sd->name[0])
164 return -EINVAL;
165
166 /*
167 * The reason to acquire the module here is to avoid unloading
168 * a module of sub-device which is registered to a media
169 * device. To make it possible to unload modules for media
170 * devices that also register sub-devices, do not
171 * try_module_get() such sub-device owners.
172 */
173 sd->owner_v4l2_dev = v4l2_dev->dev && v4l2_dev->dev->driver &&
174 sd->owner == v4l2_dev->dev->driver->owner;
175
176 if (!sd->owner_v4l2_dev && !try_module_get(sd->owner))
177 return -ENODEV;
178
179 sd->v4l2_dev = v4l2_dev;
180 /* This just returns 0 if either of the two args is NULL */
181 err = v4l2_ctrl_add_handler(v4l2_dev->ctrl_handler, sd->ctrl_handler, NULL);
182 if (err)
183 goto error_module;
184
185 #if defined(CONFIG_MEDIA_CONTROLLER)
186 /* Register the entity. */
187 if (v4l2_dev->mdev) {
188 err = media_device_register_entity(v4l2_dev->mdev, entity);
189 if (err < 0)
190 goto error_module;
191 }
192 #endif
193
194 if (sd->internal_ops && sd->internal_ops->registered) {
195 err = sd->internal_ops->registered(sd);
196 if (err)
197 goto error_unregister;
198 }
199
200 spin_lock(&v4l2_dev->lock);
201 list_add_tail(&sd->list, &v4l2_dev->subdevs);
202 spin_unlock(&v4l2_dev->lock);
203
204 return 0;
205
206 error_unregister:
207 #if defined(CONFIG_MEDIA_CONTROLLER)
208 media_device_unregister_entity(entity);
209 #endif
210 error_module:
211 if (!sd->owner_v4l2_dev)
212 module_put(sd->owner);
213 sd->v4l2_dev = NULL;
214 return err;
215 }
216 EXPORT_SYMBOL_GPL(v4l2_device_register_subdev);
217
v4l2_device_release_subdev_node(struct video_device * vdev)218 static void v4l2_device_release_subdev_node(struct video_device *vdev)
219 {
220 struct v4l2_subdev *sd = video_get_drvdata(vdev);
221 sd->devnode = NULL;
222 kfree(vdev);
223 }
224
v4l2_device_register_subdev_nodes(struct v4l2_device * v4l2_dev)225 int v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev)
226 {
227 struct video_device *vdev;
228 struct v4l2_subdev *sd;
229 int err;
230
231 /* Register a device node for every subdev marked with the
232 * V4L2_SUBDEV_FL_HAS_DEVNODE flag.
233 */
234 list_for_each_entry(sd, &v4l2_dev->subdevs, list) {
235 if (!(sd->flags & V4L2_SUBDEV_FL_HAS_DEVNODE))
236 continue;
237
238 if (sd->devnode)
239 continue;
240
241 vdev = kzalloc(sizeof(*vdev), GFP_KERNEL);
242 if (!vdev) {
243 err = -ENOMEM;
244 goto clean_up;
245 }
246
247 video_set_drvdata(vdev, sd);
248 strlcpy(vdev->name, sd->name, sizeof(vdev->name));
249 vdev->v4l2_dev = v4l2_dev;
250 vdev->fops = &v4l2_subdev_fops;
251 vdev->release = v4l2_device_release_subdev_node;
252 vdev->ctrl_handler = sd->ctrl_handler;
253 err = __video_register_device(vdev, VFL_TYPE_SUBDEV, -1, 1,
254 sd->owner);
255 if (err < 0) {
256 kfree(vdev);
257 goto clean_up;
258 }
259 sd->devnode = vdev;
260 #if defined(CONFIG_MEDIA_CONTROLLER)
261 sd->entity.info.dev.major = VIDEO_MAJOR;
262 sd->entity.info.dev.minor = vdev->minor;
263
264 /* Interface is created by __video_register_device() */
265 if (vdev->v4l2_dev->mdev) {
266 struct media_link *link;
267
268 link = media_create_intf_link(&sd->entity,
269 &vdev->intf_devnode->intf,
270 MEDIA_LNK_FL_ENABLED |
271 MEDIA_LNK_FL_IMMUTABLE);
272 if (!link) {
273 err = -ENOMEM;
274 goto clean_up;
275 }
276 }
277 #endif
278 }
279 return 0;
280
281 clean_up:
282 list_for_each_entry(sd, &v4l2_dev->subdevs, list) {
283 if (!sd->devnode)
284 break;
285 video_unregister_device(sd->devnode);
286 }
287
288 return err;
289 }
290 EXPORT_SYMBOL_GPL(v4l2_device_register_subdev_nodes);
291
v4l2_device_unregister_subdev(struct v4l2_subdev * sd)292 void v4l2_device_unregister_subdev(struct v4l2_subdev *sd)
293 {
294 struct v4l2_device *v4l2_dev;
295
296 /* return if it isn't registered */
297 if (sd == NULL || sd->v4l2_dev == NULL)
298 return;
299
300 v4l2_dev = sd->v4l2_dev;
301
302 spin_lock(&v4l2_dev->lock);
303 list_del(&sd->list);
304 spin_unlock(&v4l2_dev->lock);
305
306 if (sd->internal_ops && sd->internal_ops->unregistered)
307 sd->internal_ops->unregistered(sd);
308 sd->v4l2_dev = NULL;
309
310 #if defined(CONFIG_MEDIA_CONTROLLER)
311 if (v4l2_dev->mdev) {
312 /*
313 * No need to explicitly remove links, as both pads and
314 * links are removed by the function below, in the right order
315 */
316 media_device_unregister_entity(&sd->entity);
317 }
318 #endif
319 video_unregister_device(sd->devnode);
320 if (!sd->owner_v4l2_dev)
321 module_put(sd->owner);
322 }
323 EXPORT_SYMBOL_GPL(v4l2_device_unregister_subdev);
324