1 /*
2  * Video capture interface for Linux version 2
3  *
4  *	A generic video device interface for the LINUX operating system
5  *	using a set of device structures/vectors for low level operations.
6  *
7  *	This program is free software; you can redistribute it and/or
8  *	modify it under the terms of the GNU General Public License
9  *	as published by the Free Software Foundation; either version
10  *	2 of the License, or (at your option) any later version.
11  *
12  * Authors:	Alan Cox, <alan@lxorguk.ukuu.org.uk> (version 1)
13  *              Mauro Carvalho Chehab <mchehab@kernel.org> (version 2)
14  *
15  * Fixes:	20000516  Claudio Matsuoka <claudio@conectiva.com>
16  *		- Added procfs support
17  */
18 
19 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
20 
21 #include <linux/module.h>
22 #include <linux/types.h>
23 #include <linux/kernel.h>
24 #include <linux/mm.h>
25 #include <linux/string.h>
26 #include <linux/errno.h>
27 #include <linux/init.h>
28 #include <linux/kmod.h>
29 #include <linux/slab.h>
30 #include <linux/uaccess.h>
31 
32 #include <media/v4l2-common.h>
33 #include <media/v4l2-device.h>
34 #include <media/v4l2-ioctl.h>
35 
36 #define VIDEO_NUM_DEVICES	256
37 #define VIDEO_NAME              "video4linux"
38 
39 #define dprintk(fmt, arg...) do {					\
40 		printk(KERN_DEBUG pr_fmt("%s: " fmt),			\
41 		       __func__, ##arg);				\
42 } while (0)
43 
44 
45 /*
46  *	sysfs stuff
47  */
48 
49 static ssize_t index_show(struct device *cd,
50 			  struct device_attribute *attr, char *buf)
51 {
52 	struct video_device *vdev = to_video_device(cd);
53 
54 	return sprintf(buf, "%i\n", vdev->index);
55 }
56 static DEVICE_ATTR_RO(index);
57 
58 static ssize_t dev_debug_show(struct device *cd,
59 			  struct device_attribute *attr, char *buf)
60 {
61 	struct video_device *vdev = to_video_device(cd);
62 
63 	return sprintf(buf, "%i\n", vdev->dev_debug);
64 }
65 
66 static ssize_t dev_debug_store(struct device *cd, struct device_attribute *attr,
67 			  const char *buf, size_t len)
68 {
69 	struct video_device *vdev = to_video_device(cd);
70 	int res = 0;
71 	u16 value;
72 
73 	res = kstrtou16(buf, 0, &value);
74 	if (res)
75 		return res;
76 
77 	vdev->dev_debug = value;
78 	return len;
79 }
80 static DEVICE_ATTR_RW(dev_debug);
81 
82 static ssize_t name_show(struct device *cd,
83 			 struct device_attribute *attr, char *buf)
84 {
85 	struct video_device *vdev = to_video_device(cd);
86 
87 	return sprintf(buf, "%.*s\n", (int)sizeof(vdev->name), vdev->name);
88 }
89 static DEVICE_ATTR_RO(name);
90 
91 static struct attribute *video_device_attrs[] = {
92 	&dev_attr_name.attr,
93 	&dev_attr_dev_debug.attr,
94 	&dev_attr_index.attr,
95 	NULL,
96 };
97 ATTRIBUTE_GROUPS(video_device);
98 
99 /*
100  *	Active devices
101  */
102 static struct video_device *video_devices[VIDEO_NUM_DEVICES];
103 static DEFINE_MUTEX(videodev_lock);
104 static DECLARE_BITMAP(devnode_nums[VFL_TYPE_MAX], VIDEO_NUM_DEVICES);
105 
106 /* Device node utility functions */
107 
108 /* Note: these utility functions all assume that vfl_type is in the range
109    [0, VFL_TYPE_MAX-1]. */
110 
111 #ifdef CONFIG_VIDEO_FIXED_MINOR_RANGES
112 /* Return the bitmap corresponding to vfl_type. */
113 static inline unsigned long *devnode_bits(enum vfl_devnode_type vfl_type)
114 {
115 	/* Any types not assigned to fixed minor ranges must be mapped to
116 	   one single bitmap for the purposes of finding a free node number
117 	   since all those unassigned types use the same minor range. */
118 	int idx = (vfl_type > VFL_TYPE_RADIO) ? VFL_TYPE_MAX - 1 : vfl_type;
119 
120 	return devnode_nums[idx];
121 }
122 #else
123 /* Return the bitmap corresponding to vfl_type. */
124 static inline unsigned long *devnode_bits(enum vfl_devnode_type vfl_type)
125 {
126 	return devnode_nums[vfl_type];
127 }
128 #endif
129 
130 /* Mark device node number vdev->num as used */
131 static inline void devnode_set(struct video_device *vdev)
132 {
133 	set_bit(vdev->num, devnode_bits(vdev->vfl_type));
134 }
135 
136 /* Mark device node number vdev->num as unused */
137 static inline void devnode_clear(struct video_device *vdev)
138 {
139 	clear_bit(vdev->num, devnode_bits(vdev->vfl_type));
140 }
141 
142 /* Try to find a free device node number in the range [from, to> */
143 static inline int devnode_find(struct video_device *vdev, int from, int to)
144 {
145 	return find_next_zero_bit(devnode_bits(vdev->vfl_type), to, from);
146 }
147 
148 struct video_device *video_device_alloc(void)
149 {
150 	return kzalloc(sizeof(struct video_device), GFP_KERNEL);
151 }
152 EXPORT_SYMBOL(video_device_alloc);
153 
154 void video_device_release(struct video_device *vdev)
155 {
156 	kfree(vdev);
157 }
158 EXPORT_SYMBOL(video_device_release);
159 
160 void video_device_release_empty(struct video_device *vdev)
161 {
162 	/* Do nothing */
163 	/* Only valid when the video_device struct is a static. */
164 }
165 EXPORT_SYMBOL(video_device_release_empty);
166 
167 static inline void video_get(struct video_device *vdev)
168 {
169 	get_device(&vdev->dev);
170 }
171 
172 static inline void video_put(struct video_device *vdev)
173 {
174 	put_device(&vdev->dev);
175 }
176 
177 /* Called when the last user of the video device exits. */
178 static void v4l2_device_release(struct device *cd)
179 {
180 	struct video_device *vdev = to_video_device(cd);
181 	struct v4l2_device *v4l2_dev = vdev->v4l2_dev;
182 
183 	mutex_lock(&videodev_lock);
184 	if (WARN_ON(video_devices[vdev->minor] != vdev)) {
185 		/* should not happen */
186 		mutex_unlock(&videodev_lock);
187 		return;
188 	}
189 
190 	/* Free up this device for reuse */
191 	video_devices[vdev->minor] = NULL;
192 
193 	/* Delete the cdev on this minor as well */
194 	cdev_del(vdev->cdev);
195 	/* Just in case some driver tries to access this from
196 	   the release() callback. */
197 	vdev->cdev = NULL;
198 
199 	/* Mark device node number as free */
200 	devnode_clear(vdev);
201 
202 	mutex_unlock(&videodev_lock);
203 
204 #if defined(CONFIG_MEDIA_CONTROLLER)
205 	if (v4l2_dev->mdev && vdev->vfl_dir != VFL_DIR_M2M) {
206 		/* Remove interfaces and interface links */
207 		media_devnode_remove(vdev->intf_devnode);
208 		if (vdev->entity.function != MEDIA_ENT_F_UNKNOWN)
209 			media_device_unregister_entity(&vdev->entity);
210 	}
211 #endif
212 
213 	/* Do not call v4l2_device_put if there is no release callback set.
214 	 * Drivers that have no v4l2_device release callback might free the
215 	 * v4l2_dev instance in the video_device release callback below, so we
216 	 * must perform this check here.
217 	 *
218 	 * TODO: In the long run all drivers that use v4l2_device should use the
219 	 * v4l2_device release callback. This check will then be unnecessary.
220 	 */
221 	if (v4l2_dev->release == NULL)
222 		v4l2_dev = NULL;
223 
224 	/* Release video_device and perform other
225 	   cleanups as needed. */
226 	vdev->release(vdev);
227 
228 	/* Decrease v4l2_device refcount */
229 	if (v4l2_dev)
230 		v4l2_device_put(v4l2_dev);
231 }
232 
233 static struct class video_class = {
234 	.name = VIDEO_NAME,
235 	.dev_groups = video_device_groups,
236 };
237 
238 struct video_device *video_devdata(struct file *file)
239 {
240 	return video_devices[iminor(file_inode(file))];
241 }
242 EXPORT_SYMBOL(video_devdata);
243 
244 
245 /* Priority handling */
246 
247 static inline bool prio_is_valid(enum v4l2_priority prio)
248 {
249 	return prio == V4L2_PRIORITY_BACKGROUND ||
250 	       prio == V4L2_PRIORITY_INTERACTIVE ||
251 	       prio == V4L2_PRIORITY_RECORD;
252 }
253 
254 void v4l2_prio_init(struct v4l2_prio_state *global)
255 {
256 	memset(global, 0, sizeof(*global));
257 }
258 EXPORT_SYMBOL(v4l2_prio_init);
259 
260 int v4l2_prio_change(struct v4l2_prio_state *global, enum v4l2_priority *local,
261 		     enum v4l2_priority new)
262 {
263 	if (!prio_is_valid(new))
264 		return -EINVAL;
265 	if (*local == new)
266 		return 0;
267 
268 	atomic_inc(&global->prios[new]);
269 	if (prio_is_valid(*local))
270 		atomic_dec(&global->prios[*local]);
271 	*local = new;
272 	return 0;
273 }
274 EXPORT_SYMBOL(v4l2_prio_change);
275 
276 void v4l2_prio_open(struct v4l2_prio_state *global, enum v4l2_priority *local)
277 {
278 	v4l2_prio_change(global, local, V4L2_PRIORITY_DEFAULT);
279 }
280 EXPORT_SYMBOL(v4l2_prio_open);
281 
282 void v4l2_prio_close(struct v4l2_prio_state *global, enum v4l2_priority local)
283 {
284 	if (prio_is_valid(local))
285 		atomic_dec(&global->prios[local]);
286 }
287 EXPORT_SYMBOL(v4l2_prio_close);
288 
289 enum v4l2_priority v4l2_prio_max(struct v4l2_prio_state *global)
290 {
291 	if (atomic_read(&global->prios[V4L2_PRIORITY_RECORD]) > 0)
292 		return V4L2_PRIORITY_RECORD;
293 	if (atomic_read(&global->prios[V4L2_PRIORITY_INTERACTIVE]) > 0)
294 		return V4L2_PRIORITY_INTERACTIVE;
295 	if (atomic_read(&global->prios[V4L2_PRIORITY_BACKGROUND]) > 0)
296 		return V4L2_PRIORITY_BACKGROUND;
297 	return V4L2_PRIORITY_UNSET;
298 }
299 EXPORT_SYMBOL(v4l2_prio_max);
300 
301 int v4l2_prio_check(struct v4l2_prio_state *global, enum v4l2_priority local)
302 {
303 	return (local < v4l2_prio_max(global)) ? -EBUSY : 0;
304 }
305 EXPORT_SYMBOL(v4l2_prio_check);
306 
307 
308 static ssize_t v4l2_read(struct file *filp, char __user *buf,
309 		size_t sz, loff_t *off)
310 {
311 	struct video_device *vdev = video_devdata(filp);
312 	int ret = -ENODEV;
313 
314 	if (!vdev->fops->read)
315 		return -EINVAL;
316 	if (video_is_registered(vdev))
317 		ret = vdev->fops->read(filp, buf, sz, off);
318 	if ((vdev->dev_debug & V4L2_DEV_DEBUG_FOP) &&
319 	    (vdev->dev_debug & V4L2_DEV_DEBUG_STREAMING))
320 		dprintk("%s: read: %zd (%d)\n",
321 			video_device_node_name(vdev), sz, ret);
322 	return ret;
323 }
324 
325 static ssize_t v4l2_write(struct file *filp, const char __user *buf,
326 		size_t sz, loff_t *off)
327 {
328 	struct video_device *vdev = video_devdata(filp);
329 	int ret = -ENODEV;
330 
331 	if (!vdev->fops->write)
332 		return -EINVAL;
333 	if (video_is_registered(vdev))
334 		ret = vdev->fops->write(filp, buf, sz, off);
335 	if ((vdev->dev_debug & V4L2_DEV_DEBUG_FOP) &&
336 	    (vdev->dev_debug & V4L2_DEV_DEBUG_STREAMING))
337 		dprintk("%s: write: %zd (%d)\n",
338 			video_device_node_name(vdev), sz, ret);
339 	return ret;
340 }
341 
342 static __poll_t v4l2_poll(struct file *filp, struct poll_table_struct *poll)
343 {
344 	struct video_device *vdev = video_devdata(filp);
345 	__poll_t res = EPOLLERR | EPOLLHUP;
346 
347 	if (!vdev->fops->poll)
348 		return DEFAULT_POLLMASK;
349 	if (video_is_registered(vdev))
350 		res = vdev->fops->poll(filp, poll);
351 	if (vdev->dev_debug & V4L2_DEV_DEBUG_POLL)
352 		dprintk("%s: poll: %08x\n",
353 			video_device_node_name(vdev), res);
354 	return res;
355 }
356 
357 static long v4l2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
358 {
359 	struct video_device *vdev = video_devdata(filp);
360 	int ret = -ENODEV;
361 
362 	if (vdev->fops->unlocked_ioctl) {
363 		if (video_is_registered(vdev))
364 			ret = vdev->fops->unlocked_ioctl(filp, cmd, arg);
365 	} else
366 		ret = -ENOTTY;
367 
368 	return ret;
369 }
370 
371 #ifdef CONFIG_MMU
372 #define v4l2_get_unmapped_area NULL
373 #else
374 static unsigned long v4l2_get_unmapped_area(struct file *filp,
375 		unsigned long addr, unsigned long len, unsigned long pgoff,
376 		unsigned long flags)
377 {
378 	struct video_device *vdev = video_devdata(filp);
379 	int ret;
380 
381 	if (!vdev->fops->get_unmapped_area)
382 		return -ENOSYS;
383 	if (!video_is_registered(vdev))
384 		return -ENODEV;
385 	ret = vdev->fops->get_unmapped_area(filp, addr, len, pgoff, flags);
386 	if (vdev->dev_debug & V4L2_DEV_DEBUG_FOP)
387 		dprintk("%s: get_unmapped_area (%d)\n",
388 			video_device_node_name(vdev), ret);
389 	return ret;
390 }
391 #endif
392 
393 static int v4l2_mmap(struct file *filp, struct vm_area_struct *vm)
394 {
395 	struct video_device *vdev = video_devdata(filp);
396 	int ret = -ENODEV;
397 
398 	if (!vdev->fops->mmap)
399 		return -ENODEV;
400 	if (video_is_registered(vdev))
401 		ret = vdev->fops->mmap(filp, vm);
402 	if (vdev->dev_debug & V4L2_DEV_DEBUG_FOP)
403 		dprintk("%s: mmap (%d)\n",
404 			video_device_node_name(vdev), ret);
405 	return ret;
406 }
407 
408 /* Override for the open function */
409 static int v4l2_open(struct inode *inode, struct file *filp)
410 {
411 	struct video_device *vdev;
412 	int ret = 0;
413 
414 	/* Check if the video device is available */
415 	mutex_lock(&videodev_lock);
416 	vdev = video_devdata(filp);
417 	/* return ENODEV if the video device has already been removed. */
418 	if (vdev == NULL || !video_is_registered(vdev)) {
419 		mutex_unlock(&videodev_lock);
420 		return -ENODEV;
421 	}
422 	/* and increase the device refcount */
423 	video_get(vdev);
424 	mutex_unlock(&videodev_lock);
425 	if (vdev->fops->open) {
426 		if (video_is_registered(vdev))
427 			ret = vdev->fops->open(filp);
428 		else
429 			ret = -ENODEV;
430 	}
431 
432 	if (vdev->dev_debug & V4L2_DEV_DEBUG_FOP)
433 		dprintk("%s: open (%d)\n",
434 			video_device_node_name(vdev), ret);
435 	/* decrease the refcount in case of an error */
436 	if (ret)
437 		video_put(vdev);
438 	return ret;
439 }
440 
441 /* Override for the release function */
442 static int v4l2_release(struct inode *inode, struct file *filp)
443 {
444 	struct video_device *vdev = video_devdata(filp);
445 	int ret = 0;
446 
447 	if (vdev->fops->release)
448 		ret = vdev->fops->release(filp);
449 	if (vdev->dev_debug & V4L2_DEV_DEBUG_FOP)
450 		dprintk("%s: release\n",
451 			video_device_node_name(vdev));
452 
453 	/* decrease the refcount unconditionally since the release()
454 	   return value is ignored. */
455 	video_put(vdev);
456 	return ret;
457 }
458 
459 static const struct file_operations v4l2_fops = {
460 	.owner = THIS_MODULE,
461 	.read = v4l2_read,
462 	.write = v4l2_write,
463 	.open = v4l2_open,
464 	.get_unmapped_area = v4l2_get_unmapped_area,
465 	.mmap = v4l2_mmap,
466 	.unlocked_ioctl = v4l2_ioctl,
467 #ifdef CONFIG_COMPAT
468 	.compat_ioctl = v4l2_compat_ioctl32,
469 #endif
470 	.release = v4l2_release,
471 	.poll = v4l2_poll,
472 	.llseek = no_llseek,
473 };
474 
475 /**
476  * get_index - assign stream index number based on v4l2_dev
477  * @vdev: video_device to assign index number to, vdev->v4l2_dev should be assigned
478  *
479  * Note that when this is called the new device has not yet been registered
480  * in the video_device array, but it was able to obtain a minor number.
481  *
482  * This means that we can always obtain a free stream index number since
483  * the worst case scenario is that there are VIDEO_NUM_DEVICES - 1 slots in
484  * use of the video_device array.
485  *
486  * Returns a free index number.
487  */
488 static int get_index(struct video_device *vdev)
489 {
490 	/* This can be static since this function is called with the global
491 	   videodev_lock held. */
492 	static DECLARE_BITMAP(used, VIDEO_NUM_DEVICES);
493 	int i;
494 
495 	bitmap_zero(used, VIDEO_NUM_DEVICES);
496 
497 	for (i = 0; i < VIDEO_NUM_DEVICES; i++) {
498 		if (video_devices[i] != NULL &&
499 		    video_devices[i]->v4l2_dev == vdev->v4l2_dev) {
500 			set_bit(video_devices[i]->index, used);
501 		}
502 	}
503 
504 	return find_first_zero_bit(used, VIDEO_NUM_DEVICES);
505 }
506 
507 #define SET_VALID_IOCTL(ops, cmd, op)			\
508 	if (ops->op)					\
509 		set_bit(_IOC_NR(cmd), valid_ioctls)
510 
511 /* This determines which ioctls are actually implemented in the driver.
512    It's a one-time thing which simplifies video_ioctl2 as it can just do
513    a bit test.
514 
515    Note that drivers can override this by setting bits to 1 in
516    vdev->valid_ioctls. If an ioctl is marked as 1 when this function is
517    called, then that ioctl will actually be marked as unimplemented.
518 
519    It does that by first setting up the local valid_ioctls bitmap, and
520    at the end do a:
521 
522    vdev->valid_ioctls = valid_ioctls & ~(vdev->valid_ioctls)
523  */
524 static void determine_valid_ioctls(struct video_device *vdev)
525 {
526 	DECLARE_BITMAP(valid_ioctls, BASE_VIDIOC_PRIVATE);
527 	const struct v4l2_ioctl_ops *ops = vdev->ioctl_ops;
528 	bool is_vid = vdev->vfl_type == VFL_TYPE_GRABBER;
529 	bool is_vbi = vdev->vfl_type == VFL_TYPE_VBI;
530 	bool is_radio = vdev->vfl_type == VFL_TYPE_RADIO;
531 	bool is_sdr = vdev->vfl_type == VFL_TYPE_SDR;
532 	bool is_tch = vdev->vfl_type == VFL_TYPE_TOUCH;
533 	bool is_rx = vdev->vfl_dir != VFL_DIR_TX;
534 	bool is_tx = vdev->vfl_dir != VFL_DIR_RX;
535 
536 	bitmap_zero(valid_ioctls, BASE_VIDIOC_PRIVATE);
537 
538 	/* vfl_type and vfl_dir independent ioctls */
539 
540 	SET_VALID_IOCTL(ops, VIDIOC_QUERYCAP, vidioc_querycap);
541 	set_bit(_IOC_NR(VIDIOC_G_PRIORITY), valid_ioctls);
542 	set_bit(_IOC_NR(VIDIOC_S_PRIORITY), valid_ioctls);
543 
544 	/* Note: the control handler can also be passed through the filehandle,
545 	   and that can't be tested here. If the bit for these control ioctls
546 	   is set, then the ioctl is valid. But if it is 0, then it can still
547 	   be valid if the filehandle passed the control handler. */
548 	if (vdev->ctrl_handler || ops->vidioc_queryctrl)
549 		set_bit(_IOC_NR(VIDIOC_QUERYCTRL), valid_ioctls);
550 	if (vdev->ctrl_handler || ops->vidioc_query_ext_ctrl)
551 		set_bit(_IOC_NR(VIDIOC_QUERY_EXT_CTRL), valid_ioctls);
552 	if (vdev->ctrl_handler || ops->vidioc_g_ctrl || ops->vidioc_g_ext_ctrls)
553 		set_bit(_IOC_NR(VIDIOC_G_CTRL), valid_ioctls);
554 	if (vdev->ctrl_handler || ops->vidioc_s_ctrl || ops->vidioc_s_ext_ctrls)
555 		set_bit(_IOC_NR(VIDIOC_S_CTRL), valid_ioctls);
556 	if (vdev->ctrl_handler || ops->vidioc_g_ext_ctrls)
557 		set_bit(_IOC_NR(VIDIOC_G_EXT_CTRLS), valid_ioctls);
558 	if (vdev->ctrl_handler || ops->vidioc_s_ext_ctrls)
559 		set_bit(_IOC_NR(VIDIOC_S_EXT_CTRLS), valid_ioctls);
560 	if (vdev->ctrl_handler || ops->vidioc_try_ext_ctrls)
561 		set_bit(_IOC_NR(VIDIOC_TRY_EXT_CTRLS), valid_ioctls);
562 	if (vdev->ctrl_handler || ops->vidioc_querymenu)
563 		set_bit(_IOC_NR(VIDIOC_QUERYMENU), valid_ioctls);
564 	SET_VALID_IOCTL(ops, VIDIOC_G_FREQUENCY, vidioc_g_frequency);
565 	SET_VALID_IOCTL(ops, VIDIOC_S_FREQUENCY, vidioc_s_frequency);
566 	SET_VALID_IOCTL(ops, VIDIOC_LOG_STATUS, vidioc_log_status);
567 #ifdef CONFIG_VIDEO_ADV_DEBUG
568 	set_bit(_IOC_NR(VIDIOC_DBG_G_CHIP_INFO), valid_ioctls);
569 	set_bit(_IOC_NR(VIDIOC_DBG_G_REGISTER), valid_ioctls);
570 	set_bit(_IOC_NR(VIDIOC_DBG_S_REGISTER), valid_ioctls);
571 #endif
572 	/* yes, really vidioc_subscribe_event */
573 	SET_VALID_IOCTL(ops, VIDIOC_DQEVENT, vidioc_subscribe_event);
574 	SET_VALID_IOCTL(ops, VIDIOC_SUBSCRIBE_EVENT, vidioc_subscribe_event);
575 	SET_VALID_IOCTL(ops, VIDIOC_UNSUBSCRIBE_EVENT, vidioc_unsubscribe_event);
576 	if (ops->vidioc_enum_freq_bands || ops->vidioc_g_tuner || ops->vidioc_g_modulator)
577 		set_bit(_IOC_NR(VIDIOC_ENUM_FREQ_BANDS), valid_ioctls);
578 
579 	if (is_vid || is_tch) {
580 		/* video and metadata specific ioctls */
581 		if ((is_rx && (ops->vidioc_enum_fmt_vid_cap ||
582 			       ops->vidioc_enum_fmt_vid_cap_mplane ||
583 			       ops->vidioc_enum_fmt_vid_overlay ||
584 			       ops->vidioc_enum_fmt_meta_cap)) ||
585 		    (is_tx && (ops->vidioc_enum_fmt_vid_out ||
586 			       ops->vidioc_enum_fmt_vid_out_mplane)))
587 			set_bit(_IOC_NR(VIDIOC_ENUM_FMT), valid_ioctls);
588 		if ((is_rx && (ops->vidioc_g_fmt_vid_cap ||
589 			       ops->vidioc_g_fmt_vid_cap_mplane ||
590 			       ops->vidioc_g_fmt_vid_overlay ||
591 			       ops->vidioc_g_fmt_meta_cap)) ||
592 		    (is_tx && (ops->vidioc_g_fmt_vid_out ||
593 			       ops->vidioc_g_fmt_vid_out_mplane ||
594 			       ops->vidioc_g_fmt_vid_out_overlay)))
595 			 set_bit(_IOC_NR(VIDIOC_G_FMT), valid_ioctls);
596 		if ((is_rx && (ops->vidioc_s_fmt_vid_cap ||
597 			       ops->vidioc_s_fmt_vid_cap_mplane ||
598 			       ops->vidioc_s_fmt_vid_overlay ||
599 			       ops->vidioc_s_fmt_meta_cap)) ||
600 		    (is_tx && (ops->vidioc_s_fmt_vid_out ||
601 			       ops->vidioc_s_fmt_vid_out_mplane ||
602 			       ops->vidioc_s_fmt_vid_out_overlay)))
603 			 set_bit(_IOC_NR(VIDIOC_S_FMT), valid_ioctls);
604 		if ((is_rx && (ops->vidioc_try_fmt_vid_cap ||
605 			       ops->vidioc_try_fmt_vid_cap_mplane ||
606 			       ops->vidioc_try_fmt_vid_overlay ||
607 			       ops->vidioc_try_fmt_meta_cap)) ||
608 		    (is_tx && (ops->vidioc_try_fmt_vid_out ||
609 			       ops->vidioc_try_fmt_vid_out_mplane ||
610 			       ops->vidioc_try_fmt_vid_out_overlay)))
611 			 set_bit(_IOC_NR(VIDIOC_TRY_FMT), valid_ioctls);
612 		SET_VALID_IOCTL(ops, VIDIOC_OVERLAY, vidioc_overlay);
613 		SET_VALID_IOCTL(ops, VIDIOC_G_FBUF, vidioc_g_fbuf);
614 		SET_VALID_IOCTL(ops, VIDIOC_S_FBUF, vidioc_s_fbuf);
615 		SET_VALID_IOCTL(ops, VIDIOC_G_JPEGCOMP, vidioc_g_jpegcomp);
616 		SET_VALID_IOCTL(ops, VIDIOC_S_JPEGCOMP, vidioc_s_jpegcomp);
617 		SET_VALID_IOCTL(ops, VIDIOC_G_ENC_INDEX, vidioc_g_enc_index);
618 		SET_VALID_IOCTL(ops, VIDIOC_ENCODER_CMD, vidioc_encoder_cmd);
619 		SET_VALID_IOCTL(ops, VIDIOC_TRY_ENCODER_CMD, vidioc_try_encoder_cmd);
620 		SET_VALID_IOCTL(ops, VIDIOC_DECODER_CMD, vidioc_decoder_cmd);
621 		SET_VALID_IOCTL(ops, VIDIOC_TRY_DECODER_CMD, vidioc_try_decoder_cmd);
622 		SET_VALID_IOCTL(ops, VIDIOC_ENUM_FRAMESIZES, vidioc_enum_framesizes);
623 		SET_VALID_IOCTL(ops, VIDIOC_ENUM_FRAMEINTERVALS, vidioc_enum_frameintervals);
624 		if (ops->vidioc_g_crop || ops->vidioc_g_selection)
625 			set_bit(_IOC_NR(VIDIOC_G_CROP), valid_ioctls);
626 		if (ops->vidioc_s_crop || ops->vidioc_s_selection)
627 			set_bit(_IOC_NR(VIDIOC_S_CROP), valid_ioctls);
628 		SET_VALID_IOCTL(ops, VIDIOC_G_SELECTION, vidioc_g_selection);
629 		SET_VALID_IOCTL(ops, VIDIOC_S_SELECTION, vidioc_s_selection);
630 		if (ops->vidioc_cropcap || ops->vidioc_g_selection)
631 			set_bit(_IOC_NR(VIDIOC_CROPCAP), valid_ioctls);
632 	} else if (is_vbi) {
633 		/* vbi specific ioctls */
634 		if ((is_rx && (ops->vidioc_g_fmt_vbi_cap ||
635 			       ops->vidioc_g_fmt_sliced_vbi_cap)) ||
636 		    (is_tx && (ops->vidioc_g_fmt_vbi_out ||
637 			       ops->vidioc_g_fmt_sliced_vbi_out)))
638 			set_bit(_IOC_NR(VIDIOC_G_FMT), valid_ioctls);
639 		if ((is_rx && (ops->vidioc_s_fmt_vbi_cap ||
640 			       ops->vidioc_s_fmt_sliced_vbi_cap)) ||
641 		    (is_tx && (ops->vidioc_s_fmt_vbi_out ||
642 			       ops->vidioc_s_fmt_sliced_vbi_out)))
643 			set_bit(_IOC_NR(VIDIOC_S_FMT), valid_ioctls);
644 		if ((is_rx && (ops->vidioc_try_fmt_vbi_cap ||
645 			       ops->vidioc_try_fmt_sliced_vbi_cap)) ||
646 		    (is_tx && (ops->vidioc_try_fmt_vbi_out ||
647 			       ops->vidioc_try_fmt_sliced_vbi_out)))
648 			set_bit(_IOC_NR(VIDIOC_TRY_FMT), valid_ioctls);
649 		SET_VALID_IOCTL(ops, VIDIOC_G_SLICED_VBI_CAP, vidioc_g_sliced_vbi_cap);
650 	} else if (is_sdr && is_rx) {
651 		/* SDR receiver specific ioctls */
652 		if (ops->vidioc_enum_fmt_sdr_cap)
653 			set_bit(_IOC_NR(VIDIOC_ENUM_FMT), valid_ioctls);
654 		if (ops->vidioc_g_fmt_sdr_cap)
655 			set_bit(_IOC_NR(VIDIOC_G_FMT), valid_ioctls);
656 		if (ops->vidioc_s_fmt_sdr_cap)
657 			set_bit(_IOC_NR(VIDIOC_S_FMT), valid_ioctls);
658 		if (ops->vidioc_try_fmt_sdr_cap)
659 			set_bit(_IOC_NR(VIDIOC_TRY_FMT), valid_ioctls);
660 	} else if (is_sdr && is_tx) {
661 		/* SDR transmitter specific ioctls */
662 		if (ops->vidioc_enum_fmt_sdr_out)
663 			set_bit(_IOC_NR(VIDIOC_ENUM_FMT), valid_ioctls);
664 		if (ops->vidioc_g_fmt_sdr_out)
665 			set_bit(_IOC_NR(VIDIOC_G_FMT), valid_ioctls);
666 		if (ops->vidioc_s_fmt_sdr_out)
667 			set_bit(_IOC_NR(VIDIOC_S_FMT), valid_ioctls);
668 		if (ops->vidioc_try_fmt_sdr_out)
669 			set_bit(_IOC_NR(VIDIOC_TRY_FMT), valid_ioctls);
670 	}
671 
672 	if (is_vid || is_vbi || is_sdr || is_tch) {
673 		/* ioctls valid for video, metadata, vbi or sdr */
674 		SET_VALID_IOCTL(ops, VIDIOC_REQBUFS, vidioc_reqbufs);
675 		SET_VALID_IOCTL(ops, VIDIOC_QUERYBUF, vidioc_querybuf);
676 		SET_VALID_IOCTL(ops, VIDIOC_QBUF, vidioc_qbuf);
677 		SET_VALID_IOCTL(ops, VIDIOC_EXPBUF, vidioc_expbuf);
678 		SET_VALID_IOCTL(ops, VIDIOC_DQBUF, vidioc_dqbuf);
679 		SET_VALID_IOCTL(ops, VIDIOC_CREATE_BUFS, vidioc_create_bufs);
680 		SET_VALID_IOCTL(ops, VIDIOC_PREPARE_BUF, vidioc_prepare_buf);
681 		SET_VALID_IOCTL(ops, VIDIOC_STREAMON, vidioc_streamon);
682 		SET_VALID_IOCTL(ops, VIDIOC_STREAMOFF, vidioc_streamoff);
683 	}
684 
685 	if (is_vid || is_vbi || is_tch) {
686 		/* ioctls valid for video or vbi */
687 		if (ops->vidioc_s_std)
688 			set_bit(_IOC_NR(VIDIOC_ENUMSTD), valid_ioctls);
689 		SET_VALID_IOCTL(ops, VIDIOC_S_STD, vidioc_s_std);
690 		SET_VALID_IOCTL(ops, VIDIOC_G_STD, vidioc_g_std);
691 		if (is_rx) {
692 			SET_VALID_IOCTL(ops, VIDIOC_QUERYSTD, vidioc_querystd);
693 			SET_VALID_IOCTL(ops, VIDIOC_ENUMINPUT, vidioc_enum_input);
694 			SET_VALID_IOCTL(ops, VIDIOC_G_INPUT, vidioc_g_input);
695 			SET_VALID_IOCTL(ops, VIDIOC_S_INPUT, vidioc_s_input);
696 			SET_VALID_IOCTL(ops, VIDIOC_ENUMAUDIO, vidioc_enumaudio);
697 			SET_VALID_IOCTL(ops, VIDIOC_G_AUDIO, vidioc_g_audio);
698 			SET_VALID_IOCTL(ops, VIDIOC_S_AUDIO, vidioc_s_audio);
699 			SET_VALID_IOCTL(ops, VIDIOC_QUERY_DV_TIMINGS, vidioc_query_dv_timings);
700 			SET_VALID_IOCTL(ops, VIDIOC_S_EDID, vidioc_s_edid);
701 		}
702 		if (is_tx) {
703 			SET_VALID_IOCTL(ops, VIDIOC_ENUMOUTPUT, vidioc_enum_output);
704 			SET_VALID_IOCTL(ops, VIDIOC_G_OUTPUT, vidioc_g_output);
705 			SET_VALID_IOCTL(ops, VIDIOC_S_OUTPUT, vidioc_s_output);
706 			SET_VALID_IOCTL(ops, VIDIOC_ENUMAUDOUT, vidioc_enumaudout);
707 			SET_VALID_IOCTL(ops, VIDIOC_G_AUDOUT, vidioc_g_audout);
708 			SET_VALID_IOCTL(ops, VIDIOC_S_AUDOUT, vidioc_s_audout);
709 		}
710 		if (ops->vidioc_g_parm || (vdev->vfl_type == VFL_TYPE_GRABBER &&
711 					ops->vidioc_g_std))
712 			set_bit(_IOC_NR(VIDIOC_G_PARM), valid_ioctls);
713 		SET_VALID_IOCTL(ops, VIDIOC_S_PARM, vidioc_s_parm);
714 		SET_VALID_IOCTL(ops, VIDIOC_S_DV_TIMINGS, vidioc_s_dv_timings);
715 		SET_VALID_IOCTL(ops, VIDIOC_G_DV_TIMINGS, vidioc_g_dv_timings);
716 		SET_VALID_IOCTL(ops, VIDIOC_ENUM_DV_TIMINGS, vidioc_enum_dv_timings);
717 		SET_VALID_IOCTL(ops, VIDIOC_DV_TIMINGS_CAP, vidioc_dv_timings_cap);
718 		SET_VALID_IOCTL(ops, VIDIOC_G_EDID, vidioc_g_edid);
719 	}
720 	if (is_tx && (is_radio || is_sdr)) {
721 		/* radio transmitter only ioctls */
722 		SET_VALID_IOCTL(ops, VIDIOC_G_MODULATOR, vidioc_g_modulator);
723 		SET_VALID_IOCTL(ops, VIDIOC_S_MODULATOR, vidioc_s_modulator);
724 	}
725 	if (is_rx) {
726 		/* receiver only ioctls */
727 		SET_VALID_IOCTL(ops, VIDIOC_G_TUNER, vidioc_g_tuner);
728 		SET_VALID_IOCTL(ops, VIDIOC_S_TUNER, vidioc_s_tuner);
729 		SET_VALID_IOCTL(ops, VIDIOC_S_HW_FREQ_SEEK, vidioc_s_hw_freq_seek);
730 	}
731 
732 	bitmap_andnot(vdev->valid_ioctls, valid_ioctls, vdev->valid_ioctls,
733 			BASE_VIDIOC_PRIVATE);
734 }
735 
736 static int video_register_media_controller(struct video_device *vdev)
737 {
738 #if defined(CONFIG_MEDIA_CONTROLLER)
739 	u32 intf_type;
740 	int ret;
741 
742 	/* Memory-to-memory devices are more complex and use
743 	 * their own function to register its mc entities.
744 	 */
745 	if (!vdev->v4l2_dev->mdev || vdev->vfl_dir == VFL_DIR_M2M)
746 		return 0;
747 
748 	vdev->entity.obj_type = MEDIA_ENTITY_TYPE_VIDEO_DEVICE;
749 	vdev->entity.function = MEDIA_ENT_F_UNKNOWN;
750 
751 	switch (vdev->vfl_type) {
752 	case VFL_TYPE_GRABBER:
753 		intf_type = MEDIA_INTF_T_V4L_VIDEO;
754 		vdev->entity.function = MEDIA_ENT_F_IO_V4L;
755 		break;
756 	case VFL_TYPE_VBI:
757 		intf_type = MEDIA_INTF_T_V4L_VBI;
758 		vdev->entity.function = MEDIA_ENT_F_IO_VBI;
759 		break;
760 	case VFL_TYPE_SDR:
761 		intf_type = MEDIA_INTF_T_V4L_SWRADIO;
762 		vdev->entity.function = MEDIA_ENT_F_IO_SWRADIO;
763 		break;
764 	case VFL_TYPE_TOUCH:
765 		intf_type = MEDIA_INTF_T_V4L_TOUCH;
766 		vdev->entity.function = MEDIA_ENT_F_IO_V4L;
767 		break;
768 	case VFL_TYPE_RADIO:
769 		intf_type = MEDIA_INTF_T_V4L_RADIO;
770 		/*
771 		 * Radio doesn't have an entity at the V4L2 side to represent
772 		 * radio input or output. Instead, the audio input/output goes
773 		 * via either physical wires or ALSA.
774 		 */
775 		break;
776 	case VFL_TYPE_SUBDEV:
777 		intf_type = MEDIA_INTF_T_V4L_SUBDEV;
778 		/* Entity will be created via v4l2_device_register_subdev() */
779 		break;
780 	default:
781 		return 0;
782 	}
783 
784 	if (vdev->entity.function != MEDIA_ENT_F_UNKNOWN) {
785 		vdev->entity.name = vdev->name;
786 
787 		/* Needed just for backward compatibility with legacy MC API */
788 		vdev->entity.info.dev.major = VIDEO_MAJOR;
789 		vdev->entity.info.dev.minor = vdev->minor;
790 
791 		ret = media_device_register_entity(vdev->v4l2_dev->mdev,
792 						   &vdev->entity);
793 		if (ret < 0) {
794 			pr_warn("%s: media_device_register_entity failed\n",
795 				__func__);
796 			return ret;
797 		}
798 	}
799 
800 	vdev->intf_devnode = media_devnode_create(vdev->v4l2_dev->mdev,
801 						  intf_type,
802 						  0, VIDEO_MAJOR,
803 						  vdev->minor);
804 	if (!vdev->intf_devnode) {
805 		media_device_unregister_entity(&vdev->entity);
806 		return -ENOMEM;
807 	}
808 
809 	if (vdev->entity.function != MEDIA_ENT_F_UNKNOWN) {
810 		struct media_link *link;
811 
812 		link = media_create_intf_link(&vdev->entity,
813 					      &vdev->intf_devnode->intf,
814 					      MEDIA_LNK_FL_ENABLED |
815 					      MEDIA_LNK_FL_IMMUTABLE);
816 		if (!link) {
817 			media_devnode_remove(vdev->intf_devnode);
818 			media_device_unregister_entity(&vdev->entity);
819 			return -ENOMEM;
820 		}
821 	}
822 
823 	/* FIXME: how to create the other interface links? */
824 
825 #endif
826 	return 0;
827 }
828 
829 int __video_register_device(struct video_device *vdev,
830 			    enum vfl_devnode_type type,
831 			    int nr, int warn_if_nr_in_use,
832 			    struct module *owner)
833 {
834 	int i = 0;
835 	int ret;
836 	int minor_offset = 0;
837 	int minor_cnt = VIDEO_NUM_DEVICES;
838 	const char *name_base;
839 
840 	/* A minor value of -1 marks this video device as never
841 	   having been registered */
842 	vdev->minor = -1;
843 
844 	/* the release callback MUST be present */
845 	if (WARN_ON(!vdev->release))
846 		return -EINVAL;
847 	/* the v4l2_dev pointer MUST be present */
848 	if (WARN_ON(!vdev->v4l2_dev))
849 		return -EINVAL;
850 
851 	/* v4l2_fh support */
852 	spin_lock_init(&vdev->fh_lock);
853 	INIT_LIST_HEAD(&vdev->fh_list);
854 
855 	/* Part 1: check device type */
856 	switch (type) {
857 	case VFL_TYPE_GRABBER:
858 		name_base = "video";
859 		break;
860 	case VFL_TYPE_VBI:
861 		name_base = "vbi";
862 		break;
863 	case VFL_TYPE_RADIO:
864 		name_base = "radio";
865 		break;
866 	case VFL_TYPE_SUBDEV:
867 		name_base = "v4l-subdev";
868 		break;
869 	case VFL_TYPE_SDR:
870 		/* Use device name 'swradio' because 'sdr' was already taken. */
871 		name_base = "swradio";
872 		break;
873 	case VFL_TYPE_TOUCH:
874 		name_base = "v4l-touch";
875 		break;
876 	default:
877 		pr_err("%s called with unknown type: %d\n",
878 		       __func__, type);
879 		return -EINVAL;
880 	}
881 
882 	vdev->vfl_type = type;
883 	vdev->cdev = NULL;
884 	if (vdev->dev_parent == NULL)
885 		vdev->dev_parent = vdev->v4l2_dev->dev;
886 	if (vdev->ctrl_handler == NULL)
887 		vdev->ctrl_handler = vdev->v4l2_dev->ctrl_handler;
888 	/* If the prio state pointer is NULL, then use the v4l2_device
889 	   prio state. */
890 	if (vdev->prio == NULL)
891 		vdev->prio = &vdev->v4l2_dev->prio;
892 
893 	/* Part 2: find a free minor, device node number and device index. */
894 #ifdef CONFIG_VIDEO_FIXED_MINOR_RANGES
895 	/* Keep the ranges for the first four types for historical
896 	 * reasons.
897 	 * Newer devices (not yet in place) should use the range
898 	 * of 128-191 and just pick the first free minor there
899 	 * (new style). */
900 	switch (type) {
901 	case VFL_TYPE_GRABBER:
902 		minor_offset = 0;
903 		minor_cnt = 64;
904 		break;
905 	case VFL_TYPE_RADIO:
906 		minor_offset = 64;
907 		minor_cnt = 64;
908 		break;
909 	case VFL_TYPE_VBI:
910 		minor_offset = 224;
911 		minor_cnt = 32;
912 		break;
913 	default:
914 		minor_offset = 128;
915 		minor_cnt = 64;
916 		break;
917 	}
918 #endif
919 
920 	/* Pick a device node number */
921 	mutex_lock(&videodev_lock);
922 	nr = devnode_find(vdev, nr == -1 ? 0 : nr, minor_cnt);
923 	if (nr == minor_cnt)
924 		nr = devnode_find(vdev, 0, minor_cnt);
925 	if (nr == minor_cnt) {
926 		pr_err("could not get a free device node number\n");
927 		mutex_unlock(&videodev_lock);
928 		return -ENFILE;
929 	}
930 #ifdef CONFIG_VIDEO_FIXED_MINOR_RANGES
931 	/* 1-on-1 mapping of device node number to minor number */
932 	i = nr;
933 #else
934 	/* The device node number and minor numbers are independent, so
935 	   we just find the first free minor number. */
936 	for (i = 0; i < VIDEO_NUM_DEVICES; i++)
937 		if (video_devices[i] == NULL)
938 			break;
939 	if (i == VIDEO_NUM_DEVICES) {
940 		mutex_unlock(&videodev_lock);
941 		pr_err("could not get a free minor\n");
942 		return -ENFILE;
943 	}
944 #endif
945 	vdev->minor = i + minor_offset;
946 	vdev->num = nr;
947 
948 	/* Should not happen since we thought this minor was free */
949 	if (WARN_ON(video_devices[vdev->minor])) {
950 		mutex_unlock(&videodev_lock);
951 		pr_err("video_device not empty!\n");
952 		return -ENFILE;
953 	}
954 	devnode_set(vdev);
955 	vdev->index = get_index(vdev);
956 	video_devices[vdev->minor] = vdev;
957 	mutex_unlock(&videodev_lock);
958 
959 	if (vdev->ioctl_ops)
960 		determine_valid_ioctls(vdev);
961 
962 	/* Part 3: Initialize the character device */
963 	vdev->cdev = cdev_alloc();
964 	if (vdev->cdev == NULL) {
965 		ret = -ENOMEM;
966 		goto cleanup;
967 	}
968 	vdev->cdev->ops = &v4l2_fops;
969 	vdev->cdev->owner = owner;
970 	ret = cdev_add(vdev->cdev, MKDEV(VIDEO_MAJOR, vdev->minor), 1);
971 	if (ret < 0) {
972 		pr_err("%s: cdev_add failed\n", __func__);
973 		kfree(vdev->cdev);
974 		vdev->cdev = NULL;
975 		goto cleanup;
976 	}
977 
978 	/* Part 4: register the device with sysfs */
979 	vdev->dev.class = &video_class;
980 	vdev->dev.devt = MKDEV(VIDEO_MAJOR, vdev->minor);
981 	vdev->dev.parent = vdev->dev_parent;
982 	dev_set_name(&vdev->dev, "%s%d", name_base, vdev->num);
983 	ret = device_register(&vdev->dev);
984 	if (ret < 0) {
985 		pr_err("%s: device_register failed\n", __func__);
986 		goto cleanup;
987 	}
988 	/* Register the release callback that will be called when the last
989 	   reference to the device goes away. */
990 	vdev->dev.release = v4l2_device_release;
991 
992 	if (nr != -1 && nr != vdev->num && warn_if_nr_in_use)
993 		pr_warn("%s: requested %s%d, got %s\n", __func__,
994 			name_base, nr, video_device_node_name(vdev));
995 
996 	/* Increase v4l2_device refcount */
997 	v4l2_device_get(vdev->v4l2_dev);
998 
999 	/* Part 5: Register the entity. */
1000 	ret = video_register_media_controller(vdev);
1001 
1002 	/* Part 6: Activate this minor. The char device can now be used. */
1003 	set_bit(V4L2_FL_REGISTERED, &vdev->flags);
1004 
1005 	return 0;
1006 
1007 cleanup:
1008 	mutex_lock(&videodev_lock);
1009 	if (vdev->cdev)
1010 		cdev_del(vdev->cdev);
1011 	video_devices[vdev->minor] = NULL;
1012 	devnode_clear(vdev);
1013 	mutex_unlock(&videodev_lock);
1014 	/* Mark this video device as never having been registered. */
1015 	vdev->minor = -1;
1016 	return ret;
1017 }
1018 EXPORT_SYMBOL(__video_register_device);
1019 
1020 /**
1021  *	video_unregister_device - unregister a video4linux device
1022  *	@vdev: the device to unregister
1023  *
1024  *	This unregisters the passed device. Future open calls will
1025  *	be met with errors.
1026  */
1027 void video_unregister_device(struct video_device *vdev)
1028 {
1029 	/* Check if vdev was ever registered at all */
1030 	if (!vdev || !video_is_registered(vdev))
1031 		return;
1032 
1033 	mutex_lock(&videodev_lock);
1034 	/* This must be in a critical section to prevent a race with v4l2_open.
1035 	 * Once this bit has been cleared video_get may never be called again.
1036 	 */
1037 	clear_bit(V4L2_FL_REGISTERED, &vdev->flags);
1038 	mutex_unlock(&videodev_lock);
1039 	device_unregister(&vdev->dev);
1040 }
1041 EXPORT_SYMBOL(video_unregister_device);
1042 
1043 /*
1044  *	Initialise video for linux
1045  */
1046 static int __init videodev_init(void)
1047 {
1048 	dev_t dev = MKDEV(VIDEO_MAJOR, 0);
1049 	int ret;
1050 
1051 	pr_info("Linux video capture interface: v2.00\n");
1052 	ret = register_chrdev_region(dev, VIDEO_NUM_DEVICES, VIDEO_NAME);
1053 	if (ret < 0) {
1054 		pr_warn("videodev: unable to get major %d\n",
1055 				VIDEO_MAJOR);
1056 		return ret;
1057 	}
1058 
1059 	ret = class_register(&video_class);
1060 	if (ret < 0) {
1061 		unregister_chrdev_region(dev, VIDEO_NUM_DEVICES);
1062 		pr_warn("video_dev: class_register failed\n");
1063 		return -EIO;
1064 	}
1065 
1066 	return 0;
1067 }
1068 
1069 static void __exit videodev_exit(void)
1070 {
1071 	dev_t dev = MKDEV(VIDEO_MAJOR, 0);
1072 
1073 	class_unregister(&video_class);
1074 	unregister_chrdev_region(dev, VIDEO_NUM_DEVICES);
1075 }
1076 
1077 subsys_initcall(videodev_init);
1078 module_exit(videodev_exit)
1079 
1080 MODULE_AUTHOR("Alan Cox, Mauro Carvalho Chehab <mchehab@kernel.org>");
1081 MODULE_DESCRIPTION("Device registrar for Video4Linux drivers v2");
1082 MODULE_LICENSE("GPL");
1083 MODULE_ALIAS_CHARDEV_MAJOR(VIDEO_MAJOR);
1084