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
17int 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}
43EXPORT_SYMBOL_GPL(v4l2_device_register);
44
45static 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
54int v4l2_device_put(struct v4l2_device *v4l2_dev)
55{
56	return kref_put(&v4l2_dev->ref, v4l2_device_release);
57}
58EXPORT_SYMBOL_GPL(v4l2_device_put);
59
60int 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}
74EXPORT_SYMBOL_GPL(v4l2_device_set_name);
75
76void 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}
86EXPORT_SYMBOL_GPL(v4l2_device_disconnect);
87
88void 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}
109EXPORT_SYMBOL_GPL(v4l2_device_unregister);
110
111int v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
112				struct v4l2_subdev *sd)
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		sd->owner == v4l2_dev->dev->driver->owner;
129
130	if (!sd->owner_v4l2_dev && !try_module_get(sd->owner))
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	spin_lock(&v4l2_dev->lock);
156	list_add_tail(&sd->list, &v4l2_dev->subdevs);
157	spin_unlock(&v4l2_dev->lock);
158
159	return 0;
160
161error_unregister:
162#if defined(CONFIG_MEDIA_CONTROLLER)
163	media_device_unregister_entity(&sd->entity);
164#endif
165error_module:
166	if (!sd->owner_v4l2_dev)
167		module_put(sd->owner);
168	sd->v4l2_dev = NULL;
169	return err;
170}
171EXPORT_SYMBOL_GPL(v4l2_device_register_subdev);
172
173static void v4l2_subdev_release(struct v4l2_subdev *sd)
174{
175	struct module *owner = !sd->owner_v4l2_dev ? sd->owner : NULL;
176
177	if (sd->internal_ops && sd->internal_ops->release)
178		sd->internal_ops->release(sd);
179	sd->devnode = NULL;
180	module_put(owner);
181}
182
183static void v4l2_device_release_subdev_node(struct video_device *vdev)
184{
185	v4l2_subdev_release(video_get_drvdata(vdev));
186	kfree(vdev);
187}
188
189int __v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev,
190					bool read_only)
191{
192	struct video_device *vdev;
193	struct v4l2_subdev *sd;
194	int err;
195
196	/* Register a device node for every subdev marked with the
197	 * V4L2_SUBDEV_FL_HAS_DEVNODE flag.
198	 */
199	list_for_each_entry(sd, &v4l2_dev->subdevs, list) {
200		if (!(sd->flags & V4L2_SUBDEV_FL_HAS_DEVNODE))
201			continue;
202
203		if (sd->devnode)
204			continue;
205
206		vdev = kzalloc(sizeof(*vdev), GFP_KERNEL);
207		if (!vdev) {
208			err = -ENOMEM;
209			goto clean_up;
210		}
211
212		video_set_drvdata(vdev, sd);
213		strscpy(vdev->name, sd->name, sizeof(vdev->name));
214		vdev->dev_parent = sd->dev;
215		vdev->v4l2_dev = v4l2_dev;
216		vdev->fops = &v4l2_subdev_fops;
217		vdev->release = v4l2_device_release_subdev_node;
218		vdev->ctrl_handler = sd->ctrl_handler;
219		if (read_only)
220			set_bit(V4L2_FL_SUBDEV_RO_DEVNODE, &vdev->flags);
221		sd->devnode = vdev;
222		err = __video_register_device(vdev, VFL_TYPE_SUBDEV, -1, 1,
223					      sd->owner);
224		if (err < 0) {
225			sd->devnode = NULL;
226			kfree(vdev);
227			goto clean_up;
228		}
229#if defined(CONFIG_MEDIA_CONTROLLER)
230		sd->entity.info.dev.major = VIDEO_MAJOR;
231		sd->entity.info.dev.minor = vdev->minor;
232
233		/* Interface is created by __video_register_device() */
234		if (vdev->v4l2_dev->mdev) {
235			struct media_link *link;
236
237			link = media_create_intf_link(&sd->entity,
238						      &vdev->intf_devnode->intf,
239						      MEDIA_LNK_FL_ENABLED |
240						      MEDIA_LNK_FL_IMMUTABLE);
241			if (!link) {
242				err = -ENOMEM;
243				goto clean_up;
244			}
245		}
246#endif
247	}
248	return 0;
249
250clean_up:
251	list_for_each_entry(sd, &v4l2_dev->subdevs, list) {
252		if (!sd->devnode)
253			break;
254		video_unregister_device(sd->devnode);
255	}
256
257	return err;
258}
259EXPORT_SYMBOL_GPL(__v4l2_device_register_subdev_nodes);
260
261void v4l2_device_unregister_subdev(struct v4l2_subdev *sd)
262{
263	struct v4l2_device *v4l2_dev;
264
265	/* return if it isn't registered */
266	if (sd == NULL || sd->v4l2_dev == NULL)
267		return;
268
269	v4l2_dev = sd->v4l2_dev;
270
271	spin_lock(&v4l2_dev->lock);
272	list_del(&sd->list);
273	spin_unlock(&v4l2_dev->lock);
274
275	if (sd->internal_ops && sd->internal_ops->unregistered)
276		sd->internal_ops->unregistered(sd);
277	sd->v4l2_dev = NULL;
278
279#if defined(CONFIG_MEDIA_CONTROLLER)
280	if (v4l2_dev->mdev) {
281		/*
282		 * No need to explicitly remove links, as both pads and
283		 * links are removed by the function below, in the right order
284		 */
285		media_device_unregister_entity(&sd->entity);
286	}
287#endif
288	if (sd->devnode)
289		video_unregister_device(sd->devnode);
290	else
291		v4l2_subdev_release(sd);
292}
293EXPORT_SYMBOL_GPL(v4l2_device_unregister_subdev);
294