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@infradead.org> (version 2)
14  *
15  * Fixes:	20000516  Claudio Matsuoka <claudio@conectiva.com>
16  *		- Added procfs support
17  */
18 
19 #include <linux/module.h>
20 #include <linux/types.h>
21 #include <linux/kernel.h>
22 #include <linux/mm.h>
23 #include <linux/string.h>
24 #include <linux/errno.h>
25 #include <linux/init.h>
26 #include <linux/kmod.h>
27 #include <linux/slab.h>
28 #include <asm/uaccess.h>
29 
30 #include <media/v4l2-common.h>
31 #include <media/v4l2-device.h>
32 #include <media/v4l2-ioctl.h>
33 
34 #define VIDEO_NUM_DEVICES	256
35 #define VIDEO_NAME              "video4linux"
36 
37 /*
38  *	sysfs stuff
39  */
40 
41 static ssize_t index_show(struct device *cd,
42 			  struct device_attribute *attr, char *buf)
43 {
44 	struct video_device *vdev = to_video_device(cd);
45 
46 	return sprintf(buf, "%i\n", vdev->index);
47 }
48 static DEVICE_ATTR_RO(index);
49 
50 static ssize_t dev_debug_show(struct device *cd,
51 			  struct device_attribute *attr, char *buf)
52 {
53 	struct video_device *vdev = to_video_device(cd);
54 
55 	return sprintf(buf, "%i\n", vdev->dev_debug);
56 }
57 
58 static ssize_t dev_debug_store(struct device *cd, struct device_attribute *attr,
59 			  const char *buf, size_t len)
60 {
61 	struct video_device *vdev = to_video_device(cd);
62 	int res = 0;
63 	u16 value;
64 
65 	res = kstrtou16(buf, 0, &value);
66 	if (res)
67 		return res;
68 
69 	vdev->dev_debug = value;
70 	return len;
71 }
72 static DEVICE_ATTR_RW(dev_debug);
73 
74 static ssize_t name_show(struct device *cd,
75 			 struct device_attribute *attr, char *buf)
76 {
77 	struct video_device *vdev = to_video_device(cd);
78 
79 	return sprintf(buf, "%.*s\n", (int)sizeof(vdev->name), vdev->name);
80 }
81 static DEVICE_ATTR_RO(name);
82 
83 static struct attribute *video_device_attrs[] = {
84 	&dev_attr_name.attr,
85 	&dev_attr_dev_debug.attr,
86 	&dev_attr_index.attr,
87 	NULL,
88 };
89 ATTRIBUTE_GROUPS(video_device);
90 
91 /*
92  *	Active devices
93  */
94 static struct video_device *video_device[VIDEO_NUM_DEVICES];
95 static DEFINE_MUTEX(videodev_lock);
96 static DECLARE_BITMAP(devnode_nums[VFL_TYPE_MAX], VIDEO_NUM_DEVICES);
97 
98 /* Device node utility functions */
99 
100 /* Note: these utility functions all assume that vfl_type is in the range
101    [0, VFL_TYPE_MAX-1]. */
102 
103 #ifdef CONFIG_VIDEO_FIXED_MINOR_RANGES
104 /* Return the bitmap corresponding to vfl_type. */
105 static inline unsigned long *devnode_bits(int vfl_type)
106 {
107 	/* Any types not assigned to fixed minor ranges must be mapped to
108 	   one single bitmap for the purposes of finding a free node number
109 	   since all those unassigned types use the same minor range. */
110 	int idx = (vfl_type > VFL_TYPE_RADIO) ? VFL_TYPE_MAX - 1 : vfl_type;
111 
112 	return devnode_nums[idx];
113 }
114 #else
115 /* Return the bitmap corresponding to vfl_type. */
116 static inline unsigned long *devnode_bits(int vfl_type)
117 {
118 	return devnode_nums[vfl_type];
119 }
120 #endif
121 
122 /* Mark device node number vdev->num as used */
123 static inline void devnode_set(struct video_device *vdev)
124 {
125 	set_bit(vdev->num, devnode_bits(vdev->vfl_type));
126 }
127 
128 /* Mark device node number vdev->num as unused */
129 static inline void devnode_clear(struct video_device *vdev)
130 {
131 	clear_bit(vdev->num, devnode_bits(vdev->vfl_type));
132 }
133 
134 /* Try to find a free device node number in the range [from, to> */
135 static inline int devnode_find(struct video_device *vdev, int from, int to)
136 {
137 	return find_next_zero_bit(devnode_bits(vdev->vfl_type), to, from);
138 }
139 
140 struct video_device *video_device_alloc(void)
141 {
142 	return kzalloc(sizeof(struct video_device), GFP_KERNEL);
143 }
144 EXPORT_SYMBOL(video_device_alloc);
145 
146 void video_device_release(struct video_device *vdev)
147 {
148 	kfree(vdev);
149 }
150 EXPORT_SYMBOL(video_device_release);
151 
152 void video_device_release_empty(struct video_device *vdev)
153 {
154 	/* Do nothing */
155 	/* Only valid when the video_device struct is a static. */
156 }
157 EXPORT_SYMBOL(video_device_release_empty);
158 
159 static inline void video_get(struct video_device *vdev)
160 {
161 	get_device(&vdev->dev);
162 }
163 
164 static inline void video_put(struct video_device *vdev)
165 {
166 	put_device(&vdev->dev);
167 }
168 
169 /* Called when the last user of the video device exits. */
170 static void v4l2_device_release(struct device *cd)
171 {
172 	struct video_device *vdev = to_video_device(cd);
173 	struct v4l2_device *v4l2_dev = vdev->v4l2_dev;
174 
175 	mutex_lock(&videodev_lock);
176 	if (WARN_ON(video_device[vdev->minor] != vdev)) {
177 		/* should not happen */
178 		mutex_unlock(&videodev_lock);
179 		return;
180 	}
181 
182 	/* Free up this device for reuse */
183 	video_device[vdev->minor] = NULL;
184 
185 	/* Delete the cdev on this minor as well */
186 	cdev_del(vdev->cdev);
187 	/* Just in case some driver tries to access this from
188 	   the release() callback. */
189 	vdev->cdev = NULL;
190 
191 	/* Mark device node number as free */
192 	devnode_clear(vdev);
193 
194 	mutex_unlock(&videodev_lock);
195 
196 #if defined(CONFIG_MEDIA_CONTROLLER)
197 	if (v4l2_dev->mdev) {
198 		/* Remove interfaces and interface links */
199 		media_devnode_remove(vdev->intf_devnode);
200 		if (vdev->entity.function != MEDIA_ENT_F_UNKNOWN)
201 			media_device_unregister_entity(&vdev->entity);
202 	}
203 #endif
204 
205 	/* Do not call v4l2_device_put if there is no release callback set.
206 	 * Drivers that have no v4l2_device release callback might free the
207 	 * v4l2_dev instance in the video_device release callback below, so we
208 	 * must perform this check here.
209 	 *
210 	 * TODO: In the long run all drivers that use v4l2_device should use the
211 	 * v4l2_device release callback. This check will then be unnecessary.
212 	 */
213 	if (v4l2_dev->release == NULL)
214 		v4l2_dev = NULL;
215 
216 	/* Release video_device and perform other
217 	   cleanups as needed. */
218 	vdev->release(vdev);
219 
220 	/* Decrease v4l2_device refcount */
221 	if (v4l2_dev)
222 		v4l2_device_put(v4l2_dev);
223 }
224 
225 static struct class video_class = {
226 	.name = VIDEO_NAME,
227 	.dev_groups = video_device_groups,
228 };
229 
230 struct video_device *video_devdata(struct file *file)
231 {
232 	return video_device[iminor(file_inode(file))];
233 }
234 EXPORT_SYMBOL(video_devdata);
235 
236 
237 /* Priority handling */
238 
239 static inline bool prio_is_valid(enum v4l2_priority prio)
240 {
241 	return prio == V4L2_PRIORITY_BACKGROUND ||
242 	       prio == V4L2_PRIORITY_INTERACTIVE ||
243 	       prio == V4L2_PRIORITY_RECORD;
244 }
245 
246 void v4l2_prio_init(struct v4l2_prio_state *global)
247 {
248 	memset(global, 0, sizeof(*global));
249 }
250 EXPORT_SYMBOL(v4l2_prio_init);
251 
252 int v4l2_prio_change(struct v4l2_prio_state *global, enum v4l2_priority *local,
253 		     enum v4l2_priority new)
254 {
255 	if (!prio_is_valid(new))
256 		return -EINVAL;
257 	if (*local == new)
258 		return 0;
259 
260 	atomic_inc(&global->prios[new]);
261 	if (prio_is_valid(*local))
262 		atomic_dec(&global->prios[*local]);
263 	*local = new;
264 	return 0;
265 }
266 EXPORT_SYMBOL(v4l2_prio_change);
267 
268 void v4l2_prio_open(struct v4l2_prio_state *global, enum v4l2_priority *local)
269 {
270 	v4l2_prio_change(global, local, V4L2_PRIORITY_DEFAULT);
271 }
272 EXPORT_SYMBOL(v4l2_prio_open);
273 
274 void v4l2_prio_close(struct v4l2_prio_state *global, enum v4l2_priority local)
275 {
276 	if (prio_is_valid(local))
277 		atomic_dec(&global->prios[local]);
278 }
279 EXPORT_SYMBOL(v4l2_prio_close);
280 
281 enum v4l2_priority v4l2_prio_max(struct v4l2_prio_state *global)
282 {
283 	if (atomic_read(&global->prios[V4L2_PRIORITY_RECORD]) > 0)
284 		return V4L2_PRIORITY_RECORD;
285 	if (atomic_read(&global->prios[V4L2_PRIORITY_INTERACTIVE]) > 0)
286 		return V4L2_PRIORITY_INTERACTIVE;
287 	if (atomic_read(&global->prios[V4L2_PRIORITY_BACKGROUND]) > 0)
288 		return V4L2_PRIORITY_BACKGROUND;
289 	return V4L2_PRIORITY_UNSET;
290 }
291 EXPORT_SYMBOL(v4l2_prio_max);
292 
293 int v4l2_prio_check(struct v4l2_prio_state *global, enum v4l2_priority local)
294 {
295 	return (local < v4l2_prio_max(global)) ? -EBUSY : 0;
296 }
297 EXPORT_SYMBOL(v4l2_prio_check);
298 
299 
300 static ssize_t v4l2_read(struct file *filp, char __user *buf,
301 		size_t sz, loff_t *off)
302 {
303 	struct video_device *vdev = video_devdata(filp);
304 	int ret = -ENODEV;
305 
306 	if (!vdev->fops->read)
307 		return -EINVAL;
308 	if (video_is_registered(vdev))
309 		ret = vdev->fops->read(filp, buf, sz, off);
310 	if ((vdev->dev_debug & V4L2_DEV_DEBUG_FOP) &&
311 	    (vdev->dev_debug & V4L2_DEV_DEBUG_STREAMING))
312 		printk(KERN_DEBUG "%s: read: %zd (%d)\n",
313 			video_device_node_name(vdev), sz, ret);
314 	return ret;
315 }
316 
317 static ssize_t v4l2_write(struct file *filp, const char __user *buf,
318 		size_t sz, loff_t *off)
319 {
320 	struct video_device *vdev = video_devdata(filp);
321 	int ret = -ENODEV;
322 
323 	if (!vdev->fops->write)
324 		return -EINVAL;
325 	if (video_is_registered(vdev))
326 		ret = vdev->fops->write(filp, buf, sz, off);
327 	if ((vdev->dev_debug & V4L2_DEV_DEBUG_FOP) &&
328 	    (vdev->dev_debug & V4L2_DEV_DEBUG_STREAMING))
329 		printk(KERN_DEBUG "%s: write: %zd (%d)\n",
330 			video_device_node_name(vdev), sz, ret);
331 	return ret;
332 }
333 
334 static unsigned int v4l2_poll(struct file *filp, struct poll_table_struct *poll)
335 {
336 	struct video_device *vdev = video_devdata(filp);
337 	unsigned int res = POLLERR | POLLHUP;
338 
339 	if (!vdev->fops->poll)
340 		return DEFAULT_POLLMASK;
341 	if (video_is_registered(vdev))
342 		res = vdev->fops->poll(filp, poll);
343 	if (vdev->dev_debug & V4L2_DEV_DEBUG_POLL)
344 		printk(KERN_DEBUG "%s: poll: %08x\n",
345 			video_device_node_name(vdev), res);
346 	return res;
347 }
348 
349 static long v4l2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
350 {
351 	struct video_device *vdev = video_devdata(filp);
352 	int ret = -ENODEV;
353 
354 	if (vdev->fops->unlocked_ioctl) {
355 		struct mutex *lock = v4l2_ioctl_get_lock(vdev, cmd);
356 
357 		if (lock && mutex_lock_interruptible(lock))
358 			return -ERESTARTSYS;
359 		if (video_is_registered(vdev))
360 			ret = vdev->fops->unlocked_ioctl(filp, cmd, arg);
361 		if (lock)
362 			mutex_unlock(lock);
363 	} else
364 		ret = -ENOTTY;
365 
366 	return ret;
367 }
368 
369 #ifdef CONFIG_MMU
370 #define v4l2_get_unmapped_area NULL
371 #else
372 static unsigned long v4l2_get_unmapped_area(struct file *filp,
373 		unsigned long addr, unsigned long len, unsigned long pgoff,
374 		unsigned long flags)
375 {
376 	struct video_device *vdev = video_devdata(filp);
377 	int ret;
378 
379 	if (!vdev->fops->get_unmapped_area)
380 		return -ENOSYS;
381 	if (!video_is_registered(vdev))
382 		return -ENODEV;
383 	ret = vdev->fops->get_unmapped_area(filp, addr, len, pgoff, flags);
384 	if (vdev->dev_debug & V4L2_DEV_DEBUG_FOP)
385 		printk(KERN_DEBUG "%s: get_unmapped_area (%d)\n",
386 			video_device_node_name(vdev), ret);
387 	return ret;
388 }
389 #endif
390 
391 static int v4l2_mmap(struct file *filp, struct vm_area_struct *vm)
392 {
393 	struct video_device *vdev = video_devdata(filp);
394 	int ret = -ENODEV;
395 
396 	if (!vdev->fops->mmap)
397 		return -ENODEV;
398 	if (video_is_registered(vdev))
399 		ret = vdev->fops->mmap(filp, vm);
400 	if (vdev->dev_debug & V4L2_DEV_DEBUG_FOP)
401 		printk(KERN_DEBUG "%s: mmap (%d)\n",
402 			video_device_node_name(vdev), ret);
403 	return ret;
404 }
405 
406 /* Override for the open function */
407 static int v4l2_open(struct inode *inode, struct file *filp)
408 {
409 	struct video_device *vdev;
410 	int ret = 0;
411 
412 	/* Check if the video device is available */
413 	mutex_lock(&videodev_lock);
414 	vdev = video_devdata(filp);
415 	/* return ENODEV if the video device has already been removed. */
416 	if (vdev == NULL || !video_is_registered(vdev)) {
417 		mutex_unlock(&videodev_lock);
418 		return -ENODEV;
419 	}
420 	/* and increase the device refcount */
421 	video_get(vdev);
422 	mutex_unlock(&videodev_lock);
423 	if (vdev->fops->open) {
424 		if (video_is_registered(vdev))
425 			ret = vdev->fops->open(filp);
426 		else
427 			ret = -ENODEV;
428 	}
429 
430 	if (vdev->dev_debug & V4L2_DEV_DEBUG_FOP)
431 		printk(KERN_DEBUG "%s: open (%d)\n",
432 			video_device_node_name(vdev), ret);
433 	/* decrease the refcount in case of an error */
434 	if (ret)
435 		video_put(vdev);
436 	return ret;
437 }
438 
439 /* Override for the release function */
440 static int v4l2_release(struct inode *inode, struct file *filp)
441 {
442 	struct video_device *vdev = video_devdata(filp);
443 	int ret = 0;
444 
445 	if (vdev->fops->release)
446 		ret = vdev->fops->release(filp);
447 	if (vdev->dev_debug & V4L2_DEV_DEBUG_FOP)
448 		printk(KERN_DEBUG "%s: release\n",
449 			video_device_node_name(vdev));
450 
451 	/* decrease the refcount unconditionally since the release()
452 	   return value is ignored. */
453 	video_put(vdev);
454 	return ret;
455 }
456 
457 static const struct file_operations v4l2_fops = {
458 	.owner = THIS_MODULE,
459 	.read = v4l2_read,
460 	.write = v4l2_write,
461 	.open = v4l2_open,
462 	.get_unmapped_area = v4l2_get_unmapped_area,
463 	.mmap = v4l2_mmap,
464 	.unlocked_ioctl = v4l2_ioctl,
465 #ifdef CONFIG_COMPAT
466 	.compat_ioctl = v4l2_compat_ioctl32,
467 #endif
468 	.release = v4l2_release,
469 	.poll = v4l2_poll,
470 	.llseek = no_llseek,
471 };
472 
473 /**
474  * get_index - assign stream index number based on v4l2_dev
475  * @vdev: video_device to assign index number to, vdev->v4l2_dev should be assigned
476  *
477  * Note that when this is called the new device has not yet been registered
478  * in the video_device array, but it was able to obtain a minor number.
479  *
480  * This means that we can always obtain a free stream index number since
481  * the worst case scenario is that there are VIDEO_NUM_DEVICES - 1 slots in
482  * use of the video_device array.
483  *
484  * Returns a free index number.
485  */
486 static int get_index(struct video_device *vdev)
487 {
488 	/* This can be static since this function is called with the global
489 	   videodev_lock held. */
490 	static DECLARE_BITMAP(used, VIDEO_NUM_DEVICES);
491 	int i;
492 
493 	bitmap_zero(used, VIDEO_NUM_DEVICES);
494 
495 	for (i = 0; i < VIDEO_NUM_DEVICES; i++) {
496 		if (video_device[i] != NULL &&
497 		    video_device[i]->v4l2_dev == vdev->v4l2_dev) {
498 			set_bit(video_device[i]->index, used);
499 		}
500 	}
501 
502 	return find_first_zero_bit(used, VIDEO_NUM_DEVICES);
503 }
504 
505 #define SET_VALID_IOCTL(ops, cmd, op)			\
506 	if (ops->op)					\
507 		set_bit(_IOC_NR(cmd), valid_ioctls)
508 
509 /* This determines which ioctls are actually implemented in the driver.
510    It's a one-time thing which simplifies video_ioctl2 as it can just do
511    a bit test.
512 
513    Note that drivers can override this by setting bits to 1 in
514    vdev->valid_ioctls. If an ioctl is marked as 1 when this function is
515    called, then that ioctl will actually be marked as unimplemented.
516 
517    It does that by first setting up the local valid_ioctls bitmap, and
518    at the end do a:
519 
520    vdev->valid_ioctls = valid_ioctls & ~(vdev->valid_ioctls)
521  */
522 static void determine_valid_ioctls(struct video_device *vdev)
523 {
524 	DECLARE_BITMAP(valid_ioctls, BASE_VIDIOC_PRIVATE);
525 	const struct v4l2_ioctl_ops *ops = vdev->ioctl_ops;
526 	bool is_vid = vdev->vfl_type == VFL_TYPE_GRABBER;
527 	bool is_vbi = vdev->vfl_type == VFL_TYPE_VBI;
528 	bool is_radio = vdev->vfl_type == VFL_TYPE_RADIO;
529 	bool is_sdr = vdev->vfl_type == VFL_TYPE_SDR;
530 	bool is_rx = vdev->vfl_dir != VFL_DIR_TX;
531 	bool is_tx = vdev->vfl_dir != VFL_DIR_RX;
532 
533 	bitmap_zero(valid_ioctls, BASE_VIDIOC_PRIVATE);
534 
535 	/* vfl_type and vfl_dir independent ioctls */
536 
537 	SET_VALID_IOCTL(ops, VIDIOC_QUERYCAP, vidioc_querycap);
538 	set_bit(_IOC_NR(VIDIOC_G_PRIORITY), valid_ioctls);
539 	set_bit(_IOC_NR(VIDIOC_S_PRIORITY), valid_ioctls);
540 
541 	/* Note: the control handler can also be passed through the filehandle,
542 	   and that can't be tested here. If the bit for these control ioctls
543 	   is set, then the ioctl is valid. But if it is 0, then it can still
544 	   be valid if the filehandle passed the control handler. */
545 	if (vdev->ctrl_handler || ops->vidioc_queryctrl)
546 		set_bit(_IOC_NR(VIDIOC_QUERYCTRL), valid_ioctls);
547 	if (vdev->ctrl_handler || ops->vidioc_query_ext_ctrl)
548 		set_bit(_IOC_NR(VIDIOC_QUERY_EXT_CTRL), valid_ioctls);
549 	if (vdev->ctrl_handler || ops->vidioc_g_ctrl || ops->vidioc_g_ext_ctrls)
550 		set_bit(_IOC_NR(VIDIOC_G_CTRL), valid_ioctls);
551 	if (vdev->ctrl_handler || ops->vidioc_s_ctrl || ops->vidioc_s_ext_ctrls)
552 		set_bit(_IOC_NR(VIDIOC_S_CTRL), valid_ioctls);
553 	if (vdev->ctrl_handler || ops->vidioc_g_ext_ctrls)
554 		set_bit(_IOC_NR(VIDIOC_G_EXT_CTRLS), valid_ioctls);
555 	if (vdev->ctrl_handler || ops->vidioc_s_ext_ctrls)
556 		set_bit(_IOC_NR(VIDIOC_S_EXT_CTRLS), valid_ioctls);
557 	if (vdev->ctrl_handler || ops->vidioc_try_ext_ctrls)
558 		set_bit(_IOC_NR(VIDIOC_TRY_EXT_CTRLS), valid_ioctls);
559 	if (vdev->ctrl_handler || ops->vidioc_querymenu)
560 		set_bit(_IOC_NR(VIDIOC_QUERYMENU), valid_ioctls);
561 	SET_VALID_IOCTL(ops, VIDIOC_G_FREQUENCY, vidioc_g_frequency);
562 	SET_VALID_IOCTL(ops, VIDIOC_S_FREQUENCY, vidioc_s_frequency);
563 	SET_VALID_IOCTL(ops, VIDIOC_LOG_STATUS, vidioc_log_status);
564 #ifdef CONFIG_VIDEO_ADV_DEBUG
565 	set_bit(_IOC_NR(VIDIOC_DBG_G_CHIP_INFO), valid_ioctls);
566 	set_bit(_IOC_NR(VIDIOC_DBG_G_REGISTER), valid_ioctls);
567 	set_bit(_IOC_NR(VIDIOC_DBG_S_REGISTER), valid_ioctls);
568 #endif
569 	/* yes, really vidioc_subscribe_event */
570 	SET_VALID_IOCTL(ops, VIDIOC_DQEVENT, vidioc_subscribe_event);
571 	SET_VALID_IOCTL(ops, VIDIOC_SUBSCRIBE_EVENT, vidioc_subscribe_event);
572 	SET_VALID_IOCTL(ops, VIDIOC_UNSUBSCRIBE_EVENT, vidioc_unsubscribe_event);
573 	if (ops->vidioc_enum_freq_bands || ops->vidioc_g_tuner || ops->vidioc_g_modulator)
574 		set_bit(_IOC_NR(VIDIOC_ENUM_FREQ_BANDS), valid_ioctls);
575 
576 	if (is_vid) {
577 		/* video specific ioctls */
578 		if ((is_rx && (ops->vidioc_enum_fmt_vid_cap ||
579 			       ops->vidioc_enum_fmt_vid_cap_mplane ||
580 			       ops->vidioc_enum_fmt_vid_overlay)) ||
581 		    (is_tx && (ops->vidioc_enum_fmt_vid_out ||
582 			       ops->vidioc_enum_fmt_vid_out_mplane)))
583 			set_bit(_IOC_NR(VIDIOC_ENUM_FMT), valid_ioctls);
584 		if ((is_rx && (ops->vidioc_g_fmt_vid_cap ||
585 			       ops->vidioc_g_fmt_vid_cap_mplane ||
586 			       ops->vidioc_g_fmt_vid_overlay)) ||
587 		    (is_tx && (ops->vidioc_g_fmt_vid_out ||
588 			       ops->vidioc_g_fmt_vid_out_mplane ||
589 			       ops->vidioc_g_fmt_vid_out_overlay)))
590 			 set_bit(_IOC_NR(VIDIOC_G_FMT), valid_ioctls);
591 		if ((is_rx && (ops->vidioc_s_fmt_vid_cap ||
592 			       ops->vidioc_s_fmt_vid_cap_mplane ||
593 			       ops->vidioc_s_fmt_vid_overlay)) ||
594 		    (is_tx && (ops->vidioc_s_fmt_vid_out ||
595 			       ops->vidioc_s_fmt_vid_out_mplane ||
596 			       ops->vidioc_s_fmt_vid_out_overlay)))
597 			 set_bit(_IOC_NR(VIDIOC_S_FMT), valid_ioctls);
598 		if ((is_rx && (ops->vidioc_try_fmt_vid_cap ||
599 			       ops->vidioc_try_fmt_vid_cap_mplane ||
600 			       ops->vidioc_try_fmt_vid_overlay)) ||
601 		    (is_tx && (ops->vidioc_try_fmt_vid_out ||
602 			       ops->vidioc_try_fmt_vid_out_mplane ||
603 			       ops->vidioc_try_fmt_vid_out_overlay)))
604 			 set_bit(_IOC_NR(VIDIOC_TRY_FMT), valid_ioctls);
605 		SET_VALID_IOCTL(ops, VIDIOC_OVERLAY, vidioc_overlay);
606 		SET_VALID_IOCTL(ops, VIDIOC_G_FBUF, vidioc_g_fbuf);
607 		SET_VALID_IOCTL(ops, VIDIOC_S_FBUF, vidioc_s_fbuf);
608 		SET_VALID_IOCTL(ops, VIDIOC_G_JPEGCOMP, vidioc_g_jpegcomp);
609 		SET_VALID_IOCTL(ops, VIDIOC_S_JPEGCOMP, vidioc_s_jpegcomp);
610 		SET_VALID_IOCTL(ops, VIDIOC_G_ENC_INDEX, vidioc_g_enc_index);
611 		SET_VALID_IOCTL(ops, VIDIOC_ENCODER_CMD, vidioc_encoder_cmd);
612 		SET_VALID_IOCTL(ops, VIDIOC_TRY_ENCODER_CMD, vidioc_try_encoder_cmd);
613 		SET_VALID_IOCTL(ops, VIDIOC_DECODER_CMD, vidioc_decoder_cmd);
614 		SET_VALID_IOCTL(ops, VIDIOC_TRY_DECODER_CMD, vidioc_try_decoder_cmd);
615 		SET_VALID_IOCTL(ops, VIDIOC_ENUM_FRAMESIZES, vidioc_enum_framesizes);
616 		SET_VALID_IOCTL(ops, VIDIOC_ENUM_FRAMEINTERVALS, vidioc_enum_frameintervals);
617 		if (ops->vidioc_g_crop || ops->vidioc_g_selection)
618 			set_bit(_IOC_NR(VIDIOC_G_CROP), valid_ioctls);
619 		if (ops->vidioc_s_crop || ops->vidioc_s_selection)
620 			set_bit(_IOC_NR(VIDIOC_S_CROP), valid_ioctls);
621 		SET_VALID_IOCTL(ops, VIDIOC_G_SELECTION, vidioc_g_selection);
622 		SET_VALID_IOCTL(ops, VIDIOC_S_SELECTION, vidioc_s_selection);
623 		if (ops->vidioc_cropcap || ops->vidioc_g_selection)
624 			set_bit(_IOC_NR(VIDIOC_CROPCAP), valid_ioctls);
625 	} else if (is_vbi) {
626 		/* vbi specific ioctls */
627 		if ((is_rx && (ops->vidioc_g_fmt_vbi_cap ||
628 			       ops->vidioc_g_fmt_sliced_vbi_cap)) ||
629 		    (is_tx && (ops->vidioc_g_fmt_vbi_out ||
630 			       ops->vidioc_g_fmt_sliced_vbi_out)))
631 			set_bit(_IOC_NR(VIDIOC_G_FMT), valid_ioctls);
632 		if ((is_rx && (ops->vidioc_s_fmt_vbi_cap ||
633 			       ops->vidioc_s_fmt_sliced_vbi_cap)) ||
634 		    (is_tx && (ops->vidioc_s_fmt_vbi_out ||
635 			       ops->vidioc_s_fmt_sliced_vbi_out)))
636 			set_bit(_IOC_NR(VIDIOC_S_FMT), valid_ioctls);
637 		if ((is_rx && (ops->vidioc_try_fmt_vbi_cap ||
638 			       ops->vidioc_try_fmt_sliced_vbi_cap)) ||
639 		    (is_tx && (ops->vidioc_try_fmt_vbi_out ||
640 			       ops->vidioc_try_fmt_sliced_vbi_out)))
641 			set_bit(_IOC_NR(VIDIOC_TRY_FMT), valid_ioctls);
642 		SET_VALID_IOCTL(ops, VIDIOC_G_SLICED_VBI_CAP, vidioc_g_sliced_vbi_cap);
643 	} else if (is_sdr && is_rx) {
644 		/* SDR receiver specific ioctls */
645 		if (ops->vidioc_enum_fmt_sdr_cap)
646 			set_bit(_IOC_NR(VIDIOC_ENUM_FMT), valid_ioctls);
647 		if (ops->vidioc_g_fmt_sdr_cap)
648 			set_bit(_IOC_NR(VIDIOC_G_FMT), valid_ioctls);
649 		if (ops->vidioc_s_fmt_sdr_cap)
650 			set_bit(_IOC_NR(VIDIOC_S_FMT), valid_ioctls);
651 		if (ops->vidioc_try_fmt_sdr_cap)
652 			set_bit(_IOC_NR(VIDIOC_TRY_FMT), valid_ioctls);
653 	} else if (is_sdr && is_tx) {
654 		/* SDR transmitter specific ioctls */
655 		if (ops->vidioc_enum_fmt_sdr_out)
656 			set_bit(_IOC_NR(VIDIOC_ENUM_FMT), valid_ioctls);
657 		if (ops->vidioc_g_fmt_sdr_out)
658 			set_bit(_IOC_NR(VIDIOC_G_FMT), valid_ioctls);
659 		if (ops->vidioc_s_fmt_sdr_out)
660 			set_bit(_IOC_NR(VIDIOC_S_FMT), valid_ioctls);
661 		if (ops->vidioc_try_fmt_sdr_out)
662 			set_bit(_IOC_NR(VIDIOC_TRY_FMT), valid_ioctls);
663 	}
664 
665 	if (is_vid || is_vbi || is_sdr) {
666 		/* ioctls valid for video, vbi or sdr */
667 		SET_VALID_IOCTL(ops, VIDIOC_REQBUFS, vidioc_reqbufs);
668 		SET_VALID_IOCTL(ops, VIDIOC_QUERYBUF, vidioc_querybuf);
669 		SET_VALID_IOCTL(ops, VIDIOC_QBUF, vidioc_qbuf);
670 		SET_VALID_IOCTL(ops, VIDIOC_EXPBUF, vidioc_expbuf);
671 		SET_VALID_IOCTL(ops, VIDIOC_DQBUF, vidioc_dqbuf);
672 		SET_VALID_IOCTL(ops, VIDIOC_CREATE_BUFS, vidioc_create_bufs);
673 		SET_VALID_IOCTL(ops, VIDIOC_PREPARE_BUF, vidioc_prepare_buf);
674 		SET_VALID_IOCTL(ops, VIDIOC_STREAMON, vidioc_streamon);
675 		SET_VALID_IOCTL(ops, VIDIOC_STREAMOFF, vidioc_streamoff);
676 	}
677 
678 	if (is_vid || is_vbi) {
679 		/* ioctls valid for video or vbi */
680 		if (ops->vidioc_s_std)
681 			set_bit(_IOC_NR(VIDIOC_ENUMSTD), valid_ioctls);
682 		SET_VALID_IOCTL(ops, VIDIOC_S_STD, vidioc_s_std);
683 		SET_VALID_IOCTL(ops, VIDIOC_G_STD, vidioc_g_std);
684 		if (is_rx) {
685 			SET_VALID_IOCTL(ops, VIDIOC_QUERYSTD, vidioc_querystd);
686 			SET_VALID_IOCTL(ops, VIDIOC_ENUMINPUT, vidioc_enum_input);
687 			SET_VALID_IOCTL(ops, VIDIOC_G_INPUT, vidioc_g_input);
688 			SET_VALID_IOCTL(ops, VIDIOC_S_INPUT, vidioc_s_input);
689 			SET_VALID_IOCTL(ops, VIDIOC_ENUMAUDIO, vidioc_enumaudio);
690 			SET_VALID_IOCTL(ops, VIDIOC_G_AUDIO, vidioc_g_audio);
691 			SET_VALID_IOCTL(ops, VIDIOC_S_AUDIO, vidioc_s_audio);
692 			SET_VALID_IOCTL(ops, VIDIOC_QUERY_DV_TIMINGS, vidioc_query_dv_timings);
693 			SET_VALID_IOCTL(ops, VIDIOC_S_EDID, vidioc_s_edid);
694 		}
695 		if (is_tx) {
696 			SET_VALID_IOCTL(ops, VIDIOC_ENUMOUTPUT, vidioc_enum_output);
697 			SET_VALID_IOCTL(ops, VIDIOC_G_OUTPUT, vidioc_g_output);
698 			SET_VALID_IOCTL(ops, VIDIOC_S_OUTPUT, vidioc_s_output);
699 			SET_VALID_IOCTL(ops, VIDIOC_ENUMAUDOUT, vidioc_enumaudout);
700 			SET_VALID_IOCTL(ops, VIDIOC_G_AUDOUT, vidioc_g_audout);
701 			SET_VALID_IOCTL(ops, VIDIOC_S_AUDOUT, vidioc_s_audout);
702 		}
703 		if (ops->vidioc_g_parm || (vdev->vfl_type == VFL_TYPE_GRABBER &&
704 					ops->vidioc_g_std))
705 			set_bit(_IOC_NR(VIDIOC_G_PARM), valid_ioctls);
706 		SET_VALID_IOCTL(ops, VIDIOC_S_PARM, vidioc_s_parm);
707 		SET_VALID_IOCTL(ops, VIDIOC_S_DV_TIMINGS, vidioc_s_dv_timings);
708 		SET_VALID_IOCTL(ops, VIDIOC_G_DV_TIMINGS, vidioc_g_dv_timings);
709 		SET_VALID_IOCTL(ops, VIDIOC_ENUM_DV_TIMINGS, vidioc_enum_dv_timings);
710 		SET_VALID_IOCTL(ops, VIDIOC_DV_TIMINGS_CAP, vidioc_dv_timings_cap);
711 		SET_VALID_IOCTL(ops, VIDIOC_G_EDID, vidioc_g_edid);
712 	}
713 	if (is_tx && (is_radio || is_sdr)) {
714 		/* radio transmitter only ioctls */
715 		SET_VALID_IOCTL(ops, VIDIOC_G_MODULATOR, vidioc_g_modulator);
716 		SET_VALID_IOCTL(ops, VIDIOC_S_MODULATOR, vidioc_s_modulator);
717 	}
718 	if (is_rx) {
719 		/* receiver only ioctls */
720 		SET_VALID_IOCTL(ops, VIDIOC_G_TUNER, vidioc_g_tuner);
721 		SET_VALID_IOCTL(ops, VIDIOC_S_TUNER, vidioc_s_tuner);
722 		SET_VALID_IOCTL(ops, VIDIOC_S_HW_FREQ_SEEK, vidioc_s_hw_freq_seek);
723 	}
724 
725 	bitmap_andnot(vdev->valid_ioctls, valid_ioctls, vdev->valid_ioctls,
726 			BASE_VIDIOC_PRIVATE);
727 }
728 
729 static int video_register_media_controller(struct video_device *vdev, int type)
730 {
731 #if defined(CONFIG_MEDIA_CONTROLLER)
732 	u32 intf_type;
733 	int ret;
734 
735 	if (!vdev->v4l2_dev->mdev)
736 		return 0;
737 
738 	vdev->entity.function = MEDIA_ENT_F_UNKNOWN;
739 
740 	switch (type) {
741 	case VFL_TYPE_GRABBER:
742 		intf_type = MEDIA_INTF_T_V4L_VIDEO;
743 		vdev->entity.function = MEDIA_ENT_F_IO_V4L;
744 		break;
745 	case VFL_TYPE_VBI:
746 		intf_type = MEDIA_INTF_T_V4L_VBI;
747 		vdev->entity.function = MEDIA_ENT_F_IO_VBI;
748 		break;
749 	case VFL_TYPE_SDR:
750 		intf_type = MEDIA_INTF_T_V4L_SWRADIO;
751 		vdev->entity.function = MEDIA_ENT_F_IO_SWRADIO;
752 		break;
753 	case VFL_TYPE_RADIO:
754 		intf_type = MEDIA_INTF_T_V4L_RADIO;
755 		/*
756 		 * Radio doesn't have an entity at the V4L2 side to represent
757 		 * radio input or output. Instead, the audio input/output goes
758 		 * via either physical wires or ALSA.
759 		 */
760 		break;
761 	case VFL_TYPE_SUBDEV:
762 		intf_type = MEDIA_INTF_T_V4L_SUBDEV;
763 		/* Entity will be created via v4l2_device_register_subdev() */
764 		break;
765 	default:
766 		return 0;
767 	}
768 
769 	if (vdev->entity.function != MEDIA_ENT_F_UNKNOWN) {
770 		vdev->entity.name = vdev->name;
771 
772 		/* Needed just for backward compatibility with legacy MC API */
773 		vdev->entity.info.dev.major = VIDEO_MAJOR;
774 		vdev->entity.info.dev.minor = vdev->minor;
775 
776 		ret = media_device_register_entity(vdev->v4l2_dev->mdev,
777 						   &vdev->entity);
778 		if (ret < 0) {
779 			printk(KERN_WARNING
780 				"%s: media_device_register_entity failed\n",
781 				__func__);
782 			return ret;
783 		}
784 	}
785 
786 	vdev->intf_devnode = media_devnode_create(vdev->v4l2_dev->mdev,
787 						  intf_type,
788 						  0, VIDEO_MAJOR,
789 						  vdev->minor);
790 	if (!vdev->intf_devnode) {
791 		media_device_unregister_entity(&vdev->entity);
792 		return -ENOMEM;
793 	}
794 
795 	if (vdev->entity.function != MEDIA_ENT_F_UNKNOWN) {
796 		struct media_link *link;
797 
798 		link = media_create_intf_link(&vdev->entity,
799 					      &vdev->intf_devnode->intf,
800 					      MEDIA_LNK_FL_ENABLED);
801 		if (!link) {
802 			media_devnode_remove(vdev->intf_devnode);
803 			media_device_unregister_entity(&vdev->entity);
804 			return -ENOMEM;
805 		}
806 	}
807 
808 	/* FIXME: how to create the other interface links? */
809 
810 #endif
811 	return 0;
812 }
813 
814 /**
815  *	__video_register_device - register video4linux devices
816  *	@vdev: video device structure we want to register
817  *	@type: type of device to register
818  *	@nr:   which device node number (0 == /dev/video0, 1 == /dev/video1, ...
819  *             -1 == first free)
820  *	@warn_if_nr_in_use: warn if the desired device node number
821  *	       was already in use and another number was chosen instead.
822  *	@owner: module that owns the video device node
823  *
824  *	The registration code assigns minor numbers and device node numbers
825  *	based on the requested type and registers the new device node with
826  *	the kernel.
827  *
828  *	This function assumes that struct video_device was zeroed when it
829  *	was allocated and does not contain any stale date.
830  *
831  *	An error is returned if no free minor or device node number could be
832  *	found, or if the registration of the device node failed.
833  *
834  *	Zero is returned on success.
835  *
836  *	Valid types are
837  *
838  *	%VFL_TYPE_GRABBER - A frame grabber
839  *
840  *	%VFL_TYPE_VBI - Vertical blank data (undecoded)
841  *
842  *	%VFL_TYPE_RADIO - A radio card
843  *
844  *	%VFL_TYPE_SUBDEV - A subdevice
845  *
846  *	%VFL_TYPE_SDR - Software Defined Radio
847  */
848 int __video_register_device(struct video_device *vdev, int type, int nr,
849 		int warn_if_nr_in_use, struct module *owner)
850 {
851 	int i = 0;
852 	int ret;
853 	int minor_offset = 0;
854 	int minor_cnt = VIDEO_NUM_DEVICES;
855 	const char *name_base;
856 
857 	/* A minor value of -1 marks this video device as never
858 	   having been registered */
859 	vdev->minor = -1;
860 
861 	/* the release callback MUST be present */
862 	if (WARN_ON(!vdev->release))
863 		return -EINVAL;
864 	/* the v4l2_dev pointer MUST be present */
865 	if (WARN_ON(!vdev->v4l2_dev))
866 		return -EINVAL;
867 
868 	/* v4l2_fh support */
869 	spin_lock_init(&vdev->fh_lock);
870 	INIT_LIST_HEAD(&vdev->fh_list);
871 
872 	/* Part 1: check device type */
873 	switch (type) {
874 	case VFL_TYPE_GRABBER:
875 		name_base = "video";
876 		break;
877 	case VFL_TYPE_VBI:
878 		name_base = "vbi";
879 		break;
880 	case VFL_TYPE_RADIO:
881 		name_base = "radio";
882 		break;
883 	case VFL_TYPE_SUBDEV:
884 		name_base = "v4l-subdev";
885 		break;
886 	case VFL_TYPE_SDR:
887 		/* Use device name 'swradio' because 'sdr' was already taken. */
888 		name_base = "swradio";
889 		break;
890 	default:
891 		printk(KERN_ERR "%s called with unknown type: %d\n",
892 		       __func__, type);
893 		return -EINVAL;
894 	}
895 
896 	vdev->vfl_type = type;
897 	vdev->cdev = NULL;
898 	if (vdev->dev_parent == NULL)
899 		vdev->dev_parent = vdev->v4l2_dev->dev;
900 	if (vdev->ctrl_handler == NULL)
901 		vdev->ctrl_handler = vdev->v4l2_dev->ctrl_handler;
902 	/* If the prio state pointer is NULL, then use the v4l2_device
903 	   prio state. */
904 	if (vdev->prio == NULL)
905 		vdev->prio = &vdev->v4l2_dev->prio;
906 
907 	/* Part 2: find a free minor, device node number and device index. */
908 #ifdef CONFIG_VIDEO_FIXED_MINOR_RANGES
909 	/* Keep the ranges for the first four types for historical
910 	 * reasons.
911 	 * Newer devices (not yet in place) should use the range
912 	 * of 128-191 and just pick the first free minor there
913 	 * (new style). */
914 	switch (type) {
915 	case VFL_TYPE_GRABBER:
916 		minor_offset = 0;
917 		minor_cnt = 64;
918 		break;
919 	case VFL_TYPE_RADIO:
920 		minor_offset = 64;
921 		minor_cnt = 64;
922 		break;
923 	case VFL_TYPE_VBI:
924 		minor_offset = 224;
925 		minor_cnt = 32;
926 		break;
927 	default:
928 		minor_offset = 128;
929 		minor_cnt = 64;
930 		break;
931 	}
932 #endif
933 
934 	/* Pick a device node number */
935 	mutex_lock(&videodev_lock);
936 	nr = devnode_find(vdev, nr == -1 ? 0 : nr, minor_cnt);
937 	if (nr == minor_cnt)
938 		nr = devnode_find(vdev, 0, minor_cnt);
939 	if (nr == minor_cnt) {
940 		printk(KERN_ERR "could not get a free device node number\n");
941 		mutex_unlock(&videodev_lock);
942 		return -ENFILE;
943 	}
944 #ifdef CONFIG_VIDEO_FIXED_MINOR_RANGES
945 	/* 1-on-1 mapping of device node number to minor number */
946 	i = nr;
947 #else
948 	/* The device node number and minor numbers are independent, so
949 	   we just find the first free minor number. */
950 	for (i = 0; i < VIDEO_NUM_DEVICES; i++)
951 		if (video_device[i] == NULL)
952 			break;
953 	if (i == VIDEO_NUM_DEVICES) {
954 		mutex_unlock(&videodev_lock);
955 		printk(KERN_ERR "could not get a free minor\n");
956 		return -ENFILE;
957 	}
958 #endif
959 	vdev->minor = i + minor_offset;
960 	vdev->num = nr;
961 	devnode_set(vdev);
962 
963 	/* Should not happen since we thought this minor was free */
964 	WARN_ON(video_device[vdev->minor] != NULL);
965 	vdev->index = get_index(vdev);
966 	video_device[vdev->minor] = vdev;
967 	mutex_unlock(&videodev_lock);
968 
969 	if (vdev->ioctl_ops)
970 		determine_valid_ioctls(vdev);
971 
972 	/* Part 3: Initialize the character device */
973 	vdev->cdev = cdev_alloc();
974 	if (vdev->cdev == NULL) {
975 		ret = -ENOMEM;
976 		goto cleanup;
977 	}
978 	vdev->cdev->ops = &v4l2_fops;
979 	vdev->cdev->owner = owner;
980 	ret = cdev_add(vdev->cdev, MKDEV(VIDEO_MAJOR, vdev->minor), 1);
981 	if (ret < 0) {
982 		printk(KERN_ERR "%s: cdev_add failed\n", __func__);
983 		kfree(vdev->cdev);
984 		vdev->cdev = NULL;
985 		goto cleanup;
986 	}
987 
988 	/* Part 4: register the device with sysfs */
989 	vdev->dev.class = &video_class;
990 	vdev->dev.devt = MKDEV(VIDEO_MAJOR, vdev->minor);
991 	vdev->dev.parent = vdev->dev_parent;
992 	dev_set_name(&vdev->dev, "%s%d", name_base, vdev->num);
993 	ret = device_register(&vdev->dev);
994 	if (ret < 0) {
995 		printk(KERN_ERR "%s: device_register failed\n", __func__);
996 		goto cleanup;
997 	}
998 	/* Register the release callback that will be called when the last
999 	   reference to the device goes away. */
1000 	vdev->dev.release = v4l2_device_release;
1001 
1002 	if (nr != -1 && nr != vdev->num && warn_if_nr_in_use)
1003 		printk(KERN_WARNING "%s: requested %s%d, got %s\n", __func__,
1004 			name_base, nr, video_device_node_name(vdev));
1005 
1006 	/* Increase v4l2_device refcount */
1007 	v4l2_device_get(vdev->v4l2_dev);
1008 
1009 	/* Part 5: Register the entity. */
1010 	ret = video_register_media_controller(vdev, type);
1011 
1012 	/* Part 6: Activate this minor. The char device can now be used. */
1013 	set_bit(V4L2_FL_REGISTERED, &vdev->flags);
1014 
1015 	return 0;
1016 
1017 cleanup:
1018 	mutex_lock(&videodev_lock);
1019 	if (vdev->cdev)
1020 		cdev_del(vdev->cdev);
1021 	video_device[vdev->minor] = NULL;
1022 	devnode_clear(vdev);
1023 	mutex_unlock(&videodev_lock);
1024 	/* Mark this video device as never having been registered. */
1025 	vdev->minor = -1;
1026 	return ret;
1027 }
1028 EXPORT_SYMBOL(__video_register_device);
1029 
1030 /**
1031  *	video_unregister_device - unregister a video4linux device
1032  *	@vdev: the device to unregister
1033  *
1034  *	This unregisters the passed device. Future open calls will
1035  *	be met with errors.
1036  */
1037 void video_unregister_device(struct video_device *vdev)
1038 {
1039 	/* Check if vdev was ever registered at all */
1040 	if (!vdev || !video_is_registered(vdev))
1041 		return;
1042 
1043 	mutex_lock(&videodev_lock);
1044 	/* This must be in a critical section to prevent a race with v4l2_open.
1045 	 * Once this bit has been cleared video_get may never be called again.
1046 	 */
1047 	clear_bit(V4L2_FL_REGISTERED, &vdev->flags);
1048 	mutex_unlock(&videodev_lock);
1049 	device_unregister(&vdev->dev);
1050 }
1051 EXPORT_SYMBOL(video_unregister_device);
1052 
1053 /*
1054  *	Initialise video for linux
1055  */
1056 static int __init videodev_init(void)
1057 {
1058 	dev_t dev = MKDEV(VIDEO_MAJOR, 0);
1059 	int ret;
1060 
1061 	printk(KERN_INFO "Linux video capture interface: v2.00\n");
1062 	ret = register_chrdev_region(dev, VIDEO_NUM_DEVICES, VIDEO_NAME);
1063 	if (ret < 0) {
1064 		printk(KERN_WARNING "videodev: unable to get major %d\n",
1065 				VIDEO_MAJOR);
1066 		return ret;
1067 	}
1068 
1069 	ret = class_register(&video_class);
1070 	if (ret < 0) {
1071 		unregister_chrdev_region(dev, VIDEO_NUM_DEVICES);
1072 		printk(KERN_WARNING "video_dev: class_register failed\n");
1073 		return -EIO;
1074 	}
1075 
1076 	return 0;
1077 }
1078 
1079 static void __exit videodev_exit(void)
1080 {
1081 	dev_t dev = MKDEV(VIDEO_MAJOR, 0);
1082 
1083 	class_unregister(&video_class);
1084 	unregister_chrdev_region(dev, VIDEO_NUM_DEVICES);
1085 }
1086 
1087 subsys_initcall(videodev_init);
1088 module_exit(videodev_exit)
1089 
1090 MODULE_AUTHOR("Alan Cox, Mauro Carvalho Chehab <mchehab@infradead.org>");
1091 MODULE_DESCRIPTION("Device registrar for Video4Linux drivers v2");
1092 MODULE_LICENSE("GPL");
1093 MODULE_ALIAS_CHARDEV_MAJOR(VIDEO_MAJOR);
1094