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 	/*
448 	 * We need to serialize the release() with queueing new requests.
449 	 * The release() may trigger the cancellation of a streaming
450 	 * operation, and that should not be mixed with queueing a new
451 	 * request at the same time.
452 	 */
453 	if (vdev->fops->release) {
454 		if (v4l2_device_supports_requests(vdev->v4l2_dev)) {
455 			mutex_lock(&vdev->v4l2_dev->mdev->req_queue_mutex);
456 			ret = vdev->fops->release(filp);
457 			mutex_unlock(&vdev->v4l2_dev->mdev->req_queue_mutex);
458 		} else {
459 			ret = vdev->fops->release(filp);
460 		}
461 	}
462 
463 	if (vdev->dev_debug & V4L2_DEV_DEBUG_FOP)
464 		dprintk("%s: release\n",
465 			video_device_node_name(vdev));
466 
467 	/* decrease the refcount unconditionally since the release()
468 	   return value is ignored. */
469 	video_put(vdev);
470 	return ret;
471 }
472 
473 static const struct file_operations v4l2_fops = {
474 	.owner = THIS_MODULE,
475 	.read = v4l2_read,
476 	.write = v4l2_write,
477 	.open = v4l2_open,
478 	.get_unmapped_area = v4l2_get_unmapped_area,
479 	.mmap = v4l2_mmap,
480 	.unlocked_ioctl = v4l2_ioctl,
481 #ifdef CONFIG_COMPAT
482 	.compat_ioctl = v4l2_compat_ioctl32,
483 #endif
484 	.release = v4l2_release,
485 	.poll = v4l2_poll,
486 	.llseek = no_llseek,
487 };
488 
489 /**
490  * get_index - assign stream index number based on v4l2_dev
491  * @vdev: video_device to assign index number to, vdev->v4l2_dev should be assigned
492  *
493  * Note that when this is called the new device has not yet been registered
494  * in the video_device array, but it was able to obtain a minor number.
495  *
496  * This means that we can always obtain a free stream index number since
497  * the worst case scenario is that there are VIDEO_NUM_DEVICES - 1 slots in
498  * use of the video_device array.
499  *
500  * Returns a free index number.
501  */
502 static int get_index(struct video_device *vdev)
503 {
504 	/* This can be static since this function is called with the global
505 	   videodev_lock held. */
506 	static DECLARE_BITMAP(used, VIDEO_NUM_DEVICES);
507 	int i;
508 
509 	bitmap_zero(used, VIDEO_NUM_DEVICES);
510 
511 	for (i = 0; i < VIDEO_NUM_DEVICES; i++) {
512 		if (video_devices[i] != NULL &&
513 		    video_devices[i]->v4l2_dev == vdev->v4l2_dev) {
514 			set_bit(video_devices[i]->index, used);
515 		}
516 	}
517 
518 	return find_first_zero_bit(used, VIDEO_NUM_DEVICES);
519 }
520 
521 #define SET_VALID_IOCTL(ops, cmd, op)			\
522 	if (ops->op)					\
523 		set_bit(_IOC_NR(cmd), valid_ioctls)
524 
525 /* This determines which ioctls are actually implemented in the driver.
526    It's a one-time thing which simplifies video_ioctl2 as it can just do
527    a bit test.
528 
529    Note that drivers can override this by setting bits to 1 in
530    vdev->valid_ioctls. If an ioctl is marked as 1 when this function is
531    called, then that ioctl will actually be marked as unimplemented.
532 
533    It does that by first setting up the local valid_ioctls bitmap, and
534    at the end do a:
535 
536    vdev->valid_ioctls = valid_ioctls & ~(vdev->valid_ioctls)
537  */
538 static void determine_valid_ioctls(struct video_device *vdev)
539 {
540 	DECLARE_BITMAP(valid_ioctls, BASE_VIDIOC_PRIVATE);
541 	const struct v4l2_ioctl_ops *ops = vdev->ioctl_ops;
542 	bool is_vid = vdev->vfl_type == VFL_TYPE_GRABBER;
543 	bool is_vbi = vdev->vfl_type == VFL_TYPE_VBI;
544 	bool is_radio = vdev->vfl_type == VFL_TYPE_RADIO;
545 	bool is_sdr = vdev->vfl_type == VFL_TYPE_SDR;
546 	bool is_tch = vdev->vfl_type == VFL_TYPE_TOUCH;
547 	bool is_rx = vdev->vfl_dir != VFL_DIR_TX;
548 	bool is_tx = vdev->vfl_dir != VFL_DIR_RX;
549 
550 	bitmap_zero(valid_ioctls, BASE_VIDIOC_PRIVATE);
551 
552 	/* vfl_type and vfl_dir independent ioctls */
553 
554 	SET_VALID_IOCTL(ops, VIDIOC_QUERYCAP, vidioc_querycap);
555 	set_bit(_IOC_NR(VIDIOC_G_PRIORITY), valid_ioctls);
556 	set_bit(_IOC_NR(VIDIOC_S_PRIORITY), valid_ioctls);
557 
558 	/* Note: the control handler can also be passed through the filehandle,
559 	   and that can't be tested here. If the bit for these control ioctls
560 	   is set, then the ioctl is valid. But if it is 0, then it can still
561 	   be valid if the filehandle passed the control handler. */
562 	if (vdev->ctrl_handler || ops->vidioc_queryctrl)
563 		set_bit(_IOC_NR(VIDIOC_QUERYCTRL), valid_ioctls);
564 	if (vdev->ctrl_handler || ops->vidioc_query_ext_ctrl)
565 		set_bit(_IOC_NR(VIDIOC_QUERY_EXT_CTRL), valid_ioctls);
566 	if (vdev->ctrl_handler || ops->vidioc_g_ctrl || ops->vidioc_g_ext_ctrls)
567 		set_bit(_IOC_NR(VIDIOC_G_CTRL), valid_ioctls);
568 	if (vdev->ctrl_handler || ops->vidioc_s_ctrl || ops->vidioc_s_ext_ctrls)
569 		set_bit(_IOC_NR(VIDIOC_S_CTRL), valid_ioctls);
570 	if (vdev->ctrl_handler || ops->vidioc_g_ext_ctrls)
571 		set_bit(_IOC_NR(VIDIOC_G_EXT_CTRLS), valid_ioctls);
572 	if (vdev->ctrl_handler || ops->vidioc_s_ext_ctrls)
573 		set_bit(_IOC_NR(VIDIOC_S_EXT_CTRLS), valid_ioctls);
574 	if (vdev->ctrl_handler || ops->vidioc_try_ext_ctrls)
575 		set_bit(_IOC_NR(VIDIOC_TRY_EXT_CTRLS), valid_ioctls);
576 	if (vdev->ctrl_handler || ops->vidioc_querymenu)
577 		set_bit(_IOC_NR(VIDIOC_QUERYMENU), valid_ioctls);
578 	SET_VALID_IOCTL(ops, VIDIOC_G_FREQUENCY, vidioc_g_frequency);
579 	SET_VALID_IOCTL(ops, VIDIOC_S_FREQUENCY, vidioc_s_frequency);
580 	SET_VALID_IOCTL(ops, VIDIOC_LOG_STATUS, vidioc_log_status);
581 #ifdef CONFIG_VIDEO_ADV_DEBUG
582 	set_bit(_IOC_NR(VIDIOC_DBG_G_CHIP_INFO), valid_ioctls);
583 	set_bit(_IOC_NR(VIDIOC_DBG_G_REGISTER), valid_ioctls);
584 	set_bit(_IOC_NR(VIDIOC_DBG_S_REGISTER), valid_ioctls);
585 #endif
586 	/* yes, really vidioc_subscribe_event */
587 	SET_VALID_IOCTL(ops, VIDIOC_DQEVENT, vidioc_subscribe_event);
588 	SET_VALID_IOCTL(ops, VIDIOC_SUBSCRIBE_EVENT, vidioc_subscribe_event);
589 	SET_VALID_IOCTL(ops, VIDIOC_UNSUBSCRIBE_EVENT, vidioc_unsubscribe_event);
590 	if (ops->vidioc_enum_freq_bands || ops->vidioc_g_tuner || ops->vidioc_g_modulator)
591 		set_bit(_IOC_NR(VIDIOC_ENUM_FREQ_BANDS), valid_ioctls);
592 
593 	if (is_vid || is_tch) {
594 		/* video and metadata specific ioctls */
595 		if ((is_rx && (ops->vidioc_enum_fmt_vid_cap ||
596 			       ops->vidioc_enum_fmt_vid_cap_mplane ||
597 			       ops->vidioc_enum_fmt_vid_overlay ||
598 			       ops->vidioc_enum_fmt_meta_cap)) ||
599 		    (is_tx && (ops->vidioc_enum_fmt_vid_out ||
600 			       ops->vidioc_enum_fmt_vid_out_mplane ||
601 			       ops->vidioc_enum_fmt_meta_out)))
602 			set_bit(_IOC_NR(VIDIOC_ENUM_FMT), valid_ioctls);
603 		if ((is_rx && (ops->vidioc_g_fmt_vid_cap ||
604 			       ops->vidioc_g_fmt_vid_cap_mplane ||
605 			       ops->vidioc_g_fmt_vid_overlay ||
606 			       ops->vidioc_g_fmt_meta_cap)) ||
607 		    (is_tx && (ops->vidioc_g_fmt_vid_out ||
608 			       ops->vidioc_g_fmt_vid_out_mplane ||
609 			       ops->vidioc_g_fmt_vid_out_overlay ||
610 			       ops->vidioc_g_fmt_meta_out)))
611 			 set_bit(_IOC_NR(VIDIOC_G_FMT), valid_ioctls);
612 		if ((is_rx && (ops->vidioc_s_fmt_vid_cap ||
613 			       ops->vidioc_s_fmt_vid_cap_mplane ||
614 			       ops->vidioc_s_fmt_vid_overlay ||
615 			       ops->vidioc_s_fmt_meta_cap)) ||
616 		    (is_tx && (ops->vidioc_s_fmt_vid_out ||
617 			       ops->vidioc_s_fmt_vid_out_mplane ||
618 			       ops->vidioc_s_fmt_vid_out_overlay ||
619 			       ops->vidioc_s_fmt_meta_out)))
620 			 set_bit(_IOC_NR(VIDIOC_S_FMT), valid_ioctls);
621 		if ((is_rx && (ops->vidioc_try_fmt_vid_cap ||
622 			       ops->vidioc_try_fmt_vid_cap_mplane ||
623 			       ops->vidioc_try_fmt_vid_overlay ||
624 			       ops->vidioc_try_fmt_meta_cap)) ||
625 		    (is_tx && (ops->vidioc_try_fmt_vid_out ||
626 			       ops->vidioc_try_fmt_vid_out_mplane ||
627 			       ops->vidioc_try_fmt_vid_out_overlay ||
628 			       ops->vidioc_try_fmt_meta_out)))
629 			 set_bit(_IOC_NR(VIDIOC_TRY_FMT), valid_ioctls);
630 		SET_VALID_IOCTL(ops, VIDIOC_OVERLAY, vidioc_overlay);
631 		SET_VALID_IOCTL(ops, VIDIOC_G_FBUF, vidioc_g_fbuf);
632 		SET_VALID_IOCTL(ops, VIDIOC_S_FBUF, vidioc_s_fbuf);
633 		SET_VALID_IOCTL(ops, VIDIOC_G_JPEGCOMP, vidioc_g_jpegcomp);
634 		SET_VALID_IOCTL(ops, VIDIOC_S_JPEGCOMP, vidioc_s_jpegcomp);
635 		SET_VALID_IOCTL(ops, VIDIOC_G_ENC_INDEX, vidioc_g_enc_index);
636 		SET_VALID_IOCTL(ops, VIDIOC_ENCODER_CMD, vidioc_encoder_cmd);
637 		SET_VALID_IOCTL(ops, VIDIOC_TRY_ENCODER_CMD, vidioc_try_encoder_cmd);
638 		SET_VALID_IOCTL(ops, VIDIOC_DECODER_CMD, vidioc_decoder_cmd);
639 		SET_VALID_IOCTL(ops, VIDIOC_TRY_DECODER_CMD, vidioc_try_decoder_cmd);
640 		SET_VALID_IOCTL(ops, VIDIOC_ENUM_FRAMESIZES, vidioc_enum_framesizes);
641 		SET_VALID_IOCTL(ops, VIDIOC_ENUM_FRAMEINTERVALS, vidioc_enum_frameintervals);
642 		if (ops->vidioc_g_selection) {
643 			set_bit(_IOC_NR(VIDIOC_G_CROP), valid_ioctls);
644 			set_bit(_IOC_NR(VIDIOC_CROPCAP), valid_ioctls);
645 		}
646 		if (ops->vidioc_s_selection)
647 			set_bit(_IOC_NR(VIDIOC_S_CROP), valid_ioctls);
648 		SET_VALID_IOCTL(ops, VIDIOC_G_SELECTION, vidioc_g_selection);
649 		SET_VALID_IOCTL(ops, VIDIOC_S_SELECTION, vidioc_s_selection);
650 	} else if (is_vbi) {
651 		/* vbi specific ioctls */
652 		if ((is_rx && (ops->vidioc_g_fmt_vbi_cap ||
653 			       ops->vidioc_g_fmt_sliced_vbi_cap)) ||
654 		    (is_tx && (ops->vidioc_g_fmt_vbi_out ||
655 			       ops->vidioc_g_fmt_sliced_vbi_out)))
656 			set_bit(_IOC_NR(VIDIOC_G_FMT), valid_ioctls);
657 		if ((is_rx && (ops->vidioc_s_fmt_vbi_cap ||
658 			       ops->vidioc_s_fmt_sliced_vbi_cap)) ||
659 		    (is_tx && (ops->vidioc_s_fmt_vbi_out ||
660 			       ops->vidioc_s_fmt_sliced_vbi_out)))
661 			set_bit(_IOC_NR(VIDIOC_S_FMT), valid_ioctls);
662 		if ((is_rx && (ops->vidioc_try_fmt_vbi_cap ||
663 			       ops->vidioc_try_fmt_sliced_vbi_cap)) ||
664 		    (is_tx && (ops->vidioc_try_fmt_vbi_out ||
665 			       ops->vidioc_try_fmt_sliced_vbi_out)))
666 			set_bit(_IOC_NR(VIDIOC_TRY_FMT), valid_ioctls);
667 		SET_VALID_IOCTL(ops, VIDIOC_G_SLICED_VBI_CAP, vidioc_g_sliced_vbi_cap);
668 	} else if (is_sdr && is_rx) {
669 		/* SDR receiver specific ioctls */
670 		if (ops->vidioc_enum_fmt_sdr_cap)
671 			set_bit(_IOC_NR(VIDIOC_ENUM_FMT), valid_ioctls);
672 		if (ops->vidioc_g_fmt_sdr_cap)
673 			set_bit(_IOC_NR(VIDIOC_G_FMT), valid_ioctls);
674 		if (ops->vidioc_s_fmt_sdr_cap)
675 			set_bit(_IOC_NR(VIDIOC_S_FMT), valid_ioctls);
676 		if (ops->vidioc_try_fmt_sdr_cap)
677 			set_bit(_IOC_NR(VIDIOC_TRY_FMT), valid_ioctls);
678 	} else if (is_sdr && is_tx) {
679 		/* SDR transmitter specific ioctls */
680 		if (ops->vidioc_enum_fmt_sdr_out)
681 			set_bit(_IOC_NR(VIDIOC_ENUM_FMT), valid_ioctls);
682 		if (ops->vidioc_g_fmt_sdr_out)
683 			set_bit(_IOC_NR(VIDIOC_G_FMT), valid_ioctls);
684 		if (ops->vidioc_s_fmt_sdr_out)
685 			set_bit(_IOC_NR(VIDIOC_S_FMT), valid_ioctls);
686 		if (ops->vidioc_try_fmt_sdr_out)
687 			set_bit(_IOC_NR(VIDIOC_TRY_FMT), valid_ioctls);
688 	}
689 
690 	if (is_vid || is_vbi || is_sdr || is_tch) {
691 		/* ioctls valid for video, metadata, vbi or sdr */
692 		SET_VALID_IOCTL(ops, VIDIOC_REQBUFS, vidioc_reqbufs);
693 		SET_VALID_IOCTL(ops, VIDIOC_QUERYBUF, vidioc_querybuf);
694 		SET_VALID_IOCTL(ops, VIDIOC_QBUF, vidioc_qbuf);
695 		SET_VALID_IOCTL(ops, VIDIOC_EXPBUF, vidioc_expbuf);
696 		SET_VALID_IOCTL(ops, VIDIOC_DQBUF, vidioc_dqbuf);
697 		SET_VALID_IOCTL(ops, VIDIOC_CREATE_BUFS, vidioc_create_bufs);
698 		SET_VALID_IOCTL(ops, VIDIOC_PREPARE_BUF, vidioc_prepare_buf);
699 		SET_VALID_IOCTL(ops, VIDIOC_STREAMON, vidioc_streamon);
700 		SET_VALID_IOCTL(ops, VIDIOC_STREAMOFF, vidioc_streamoff);
701 	}
702 
703 	if (is_vid || is_vbi || is_tch) {
704 		/* ioctls valid for video or vbi */
705 		if (ops->vidioc_s_std)
706 			set_bit(_IOC_NR(VIDIOC_ENUMSTD), valid_ioctls);
707 		SET_VALID_IOCTL(ops, VIDIOC_S_STD, vidioc_s_std);
708 		SET_VALID_IOCTL(ops, VIDIOC_G_STD, vidioc_g_std);
709 		if (is_rx) {
710 			SET_VALID_IOCTL(ops, VIDIOC_QUERYSTD, vidioc_querystd);
711 			SET_VALID_IOCTL(ops, VIDIOC_ENUMINPUT, vidioc_enum_input);
712 			SET_VALID_IOCTL(ops, VIDIOC_G_INPUT, vidioc_g_input);
713 			SET_VALID_IOCTL(ops, VIDIOC_S_INPUT, vidioc_s_input);
714 			SET_VALID_IOCTL(ops, VIDIOC_ENUMAUDIO, vidioc_enumaudio);
715 			SET_VALID_IOCTL(ops, VIDIOC_G_AUDIO, vidioc_g_audio);
716 			SET_VALID_IOCTL(ops, VIDIOC_S_AUDIO, vidioc_s_audio);
717 			SET_VALID_IOCTL(ops, VIDIOC_QUERY_DV_TIMINGS, vidioc_query_dv_timings);
718 			SET_VALID_IOCTL(ops, VIDIOC_S_EDID, vidioc_s_edid);
719 		}
720 		if (is_tx) {
721 			SET_VALID_IOCTL(ops, VIDIOC_ENUMOUTPUT, vidioc_enum_output);
722 			SET_VALID_IOCTL(ops, VIDIOC_G_OUTPUT, vidioc_g_output);
723 			SET_VALID_IOCTL(ops, VIDIOC_S_OUTPUT, vidioc_s_output);
724 			SET_VALID_IOCTL(ops, VIDIOC_ENUMAUDOUT, vidioc_enumaudout);
725 			SET_VALID_IOCTL(ops, VIDIOC_G_AUDOUT, vidioc_g_audout);
726 			SET_VALID_IOCTL(ops, VIDIOC_S_AUDOUT, vidioc_s_audout);
727 		}
728 		if (ops->vidioc_g_parm || (vdev->vfl_type == VFL_TYPE_GRABBER &&
729 					ops->vidioc_g_std))
730 			set_bit(_IOC_NR(VIDIOC_G_PARM), valid_ioctls);
731 		SET_VALID_IOCTL(ops, VIDIOC_S_PARM, vidioc_s_parm);
732 		SET_VALID_IOCTL(ops, VIDIOC_S_DV_TIMINGS, vidioc_s_dv_timings);
733 		SET_VALID_IOCTL(ops, VIDIOC_G_DV_TIMINGS, vidioc_g_dv_timings);
734 		SET_VALID_IOCTL(ops, VIDIOC_ENUM_DV_TIMINGS, vidioc_enum_dv_timings);
735 		SET_VALID_IOCTL(ops, VIDIOC_DV_TIMINGS_CAP, vidioc_dv_timings_cap);
736 		SET_VALID_IOCTL(ops, VIDIOC_G_EDID, vidioc_g_edid);
737 	}
738 	if (is_tx && (is_radio || is_sdr)) {
739 		/* radio transmitter only ioctls */
740 		SET_VALID_IOCTL(ops, VIDIOC_G_MODULATOR, vidioc_g_modulator);
741 		SET_VALID_IOCTL(ops, VIDIOC_S_MODULATOR, vidioc_s_modulator);
742 	}
743 	if (is_rx) {
744 		/* receiver only ioctls */
745 		SET_VALID_IOCTL(ops, VIDIOC_G_TUNER, vidioc_g_tuner);
746 		SET_VALID_IOCTL(ops, VIDIOC_S_TUNER, vidioc_s_tuner);
747 		SET_VALID_IOCTL(ops, VIDIOC_S_HW_FREQ_SEEK, vidioc_s_hw_freq_seek);
748 	}
749 
750 	bitmap_andnot(vdev->valid_ioctls, valid_ioctls, vdev->valid_ioctls,
751 			BASE_VIDIOC_PRIVATE);
752 }
753 
754 static int video_register_media_controller(struct video_device *vdev)
755 {
756 #if defined(CONFIG_MEDIA_CONTROLLER)
757 	u32 intf_type;
758 	int ret;
759 
760 	/* Memory-to-memory devices are more complex and use
761 	 * their own function to register its mc entities.
762 	 */
763 	if (!vdev->v4l2_dev->mdev || vdev->vfl_dir == VFL_DIR_M2M)
764 		return 0;
765 
766 	vdev->entity.obj_type = MEDIA_ENTITY_TYPE_VIDEO_DEVICE;
767 	vdev->entity.function = MEDIA_ENT_F_UNKNOWN;
768 
769 	switch (vdev->vfl_type) {
770 	case VFL_TYPE_GRABBER:
771 		intf_type = MEDIA_INTF_T_V4L_VIDEO;
772 		vdev->entity.function = MEDIA_ENT_F_IO_V4L;
773 		break;
774 	case VFL_TYPE_VBI:
775 		intf_type = MEDIA_INTF_T_V4L_VBI;
776 		vdev->entity.function = MEDIA_ENT_F_IO_VBI;
777 		break;
778 	case VFL_TYPE_SDR:
779 		intf_type = MEDIA_INTF_T_V4L_SWRADIO;
780 		vdev->entity.function = MEDIA_ENT_F_IO_SWRADIO;
781 		break;
782 	case VFL_TYPE_TOUCH:
783 		intf_type = MEDIA_INTF_T_V4L_TOUCH;
784 		vdev->entity.function = MEDIA_ENT_F_IO_V4L;
785 		break;
786 	case VFL_TYPE_RADIO:
787 		intf_type = MEDIA_INTF_T_V4L_RADIO;
788 		/*
789 		 * Radio doesn't have an entity at the V4L2 side to represent
790 		 * radio input or output. Instead, the audio input/output goes
791 		 * via either physical wires or ALSA.
792 		 */
793 		break;
794 	case VFL_TYPE_SUBDEV:
795 		intf_type = MEDIA_INTF_T_V4L_SUBDEV;
796 		/* Entity will be created via v4l2_device_register_subdev() */
797 		break;
798 	default:
799 		return 0;
800 	}
801 
802 	if (vdev->entity.function != MEDIA_ENT_F_UNKNOWN) {
803 		vdev->entity.name = vdev->name;
804 
805 		/* Needed just for backward compatibility with legacy MC API */
806 		vdev->entity.info.dev.major = VIDEO_MAJOR;
807 		vdev->entity.info.dev.minor = vdev->minor;
808 
809 		ret = media_device_register_entity(vdev->v4l2_dev->mdev,
810 						   &vdev->entity);
811 		if (ret < 0) {
812 			pr_warn("%s: media_device_register_entity failed\n",
813 				__func__);
814 			return ret;
815 		}
816 	}
817 
818 	vdev->intf_devnode = media_devnode_create(vdev->v4l2_dev->mdev,
819 						  intf_type,
820 						  0, VIDEO_MAJOR,
821 						  vdev->minor);
822 	if (!vdev->intf_devnode) {
823 		media_device_unregister_entity(&vdev->entity);
824 		return -ENOMEM;
825 	}
826 
827 	if (vdev->entity.function != MEDIA_ENT_F_UNKNOWN) {
828 		struct media_link *link;
829 
830 		link = media_create_intf_link(&vdev->entity,
831 					      &vdev->intf_devnode->intf,
832 					      MEDIA_LNK_FL_ENABLED |
833 					      MEDIA_LNK_FL_IMMUTABLE);
834 		if (!link) {
835 			media_devnode_remove(vdev->intf_devnode);
836 			media_device_unregister_entity(&vdev->entity);
837 			return -ENOMEM;
838 		}
839 	}
840 
841 	/* FIXME: how to create the other interface links? */
842 
843 #endif
844 	return 0;
845 }
846 
847 int __video_register_device(struct video_device *vdev,
848 			    enum vfl_devnode_type type,
849 			    int nr, int warn_if_nr_in_use,
850 			    struct module *owner)
851 {
852 	int i = 0;
853 	int ret;
854 	int minor_offset = 0;
855 	int minor_cnt = VIDEO_NUM_DEVICES;
856 	const char *name_base;
857 
858 	/* A minor value of -1 marks this video device as never
859 	   having been registered */
860 	vdev->minor = -1;
861 
862 	/* the release callback MUST be present */
863 	if (WARN_ON(!vdev->release))
864 		return -EINVAL;
865 	/* the v4l2_dev pointer MUST be present */
866 	if (WARN_ON(!vdev->v4l2_dev))
867 		return -EINVAL;
868 
869 	/* v4l2_fh support */
870 	spin_lock_init(&vdev->fh_lock);
871 	INIT_LIST_HEAD(&vdev->fh_list);
872 
873 	/* Part 1: check device type */
874 	switch (type) {
875 	case VFL_TYPE_GRABBER:
876 		name_base = "video";
877 		break;
878 	case VFL_TYPE_VBI:
879 		name_base = "vbi";
880 		break;
881 	case VFL_TYPE_RADIO:
882 		name_base = "radio";
883 		break;
884 	case VFL_TYPE_SUBDEV:
885 		name_base = "v4l-subdev";
886 		break;
887 	case VFL_TYPE_SDR:
888 		/* Use device name 'swradio' because 'sdr' was already taken. */
889 		name_base = "swradio";
890 		break;
891 	case VFL_TYPE_TOUCH:
892 		name_base = "v4l-touch";
893 		break;
894 	default:
895 		pr_err("%s called with unknown type: %d\n",
896 		       __func__, type);
897 		return -EINVAL;
898 	}
899 
900 	vdev->vfl_type = type;
901 	vdev->cdev = NULL;
902 	if (vdev->dev_parent == NULL)
903 		vdev->dev_parent = vdev->v4l2_dev->dev;
904 	if (vdev->ctrl_handler == NULL)
905 		vdev->ctrl_handler = vdev->v4l2_dev->ctrl_handler;
906 	/* If the prio state pointer is NULL, then use the v4l2_device
907 	   prio state. */
908 	if (vdev->prio == NULL)
909 		vdev->prio = &vdev->v4l2_dev->prio;
910 
911 	/* Part 2: find a free minor, device node number and device index. */
912 #ifdef CONFIG_VIDEO_FIXED_MINOR_RANGES
913 	/* Keep the ranges for the first four types for historical
914 	 * reasons.
915 	 * Newer devices (not yet in place) should use the range
916 	 * of 128-191 and just pick the first free minor there
917 	 * (new style). */
918 	switch (type) {
919 	case VFL_TYPE_GRABBER:
920 		minor_offset = 0;
921 		minor_cnt = 64;
922 		break;
923 	case VFL_TYPE_RADIO:
924 		minor_offset = 64;
925 		minor_cnt = 64;
926 		break;
927 	case VFL_TYPE_VBI:
928 		minor_offset = 224;
929 		minor_cnt = 32;
930 		break;
931 	default:
932 		minor_offset = 128;
933 		minor_cnt = 64;
934 		break;
935 	}
936 #endif
937 
938 	/* Pick a device node number */
939 	mutex_lock(&videodev_lock);
940 	nr = devnode_find(vdev, nr == -1 ? 0 : nr, minor_cnt);
941 	if (nr == minor_cnt)
942 		nr = devnode_find(vdev, 0, minor_cnt);
943 	if (nr == minor_cnt) {
944 		pr_err("could not get a free device node number\n");
945 		mutex_unlock(&videodev_lock);
946 		return -ENFILE;
947 	}
948 #ifdef CONFIG_VIDEO_FIXED_MINOR_RANGES
949 	/* 1-on-1 mapping of device node number to minor number */
950 	i = nr;
951 #else
952 	/* The device node number and minor numbers are independent, so
953 	   we just find the first free minor number. */
954 	for (i = 0; i < VIDEO_NUM_DEVICES; i++)
955 		if (video_devices[i] == NULL)
956 			break;
957 	if (i == VIDEO_NUM_DEVICES) {
958 		mutex_unlock(&videodev_lock);
959 		pr_err("could not get a free minor\n");
960 		return -ENFILE;
961 	}
962 #endif
963 	vdev->minor = i + minor_offset;
964 	vdev->num = nr;
965 
966 	/* Should not happen since we thought this minor was free */
967 	if (WARN_ON(video_devices[vdev->minor])) {
968 		mutex_unlock(&videodev_lock);
969 		pr_err("video_device not empty!\n");
970 		return -ENFILE;
971 	}
972 	devnode_set(vdev);
973 	vdev->index = get_index(vdev);
974 	video_devices[vdev->minor] = vdev;
975 	mutex_unlock(&videodev_lock);
976 
977 	if (vdev->ioctl_ops)
978 		determine_valid_ioctls(vdev);
979 
980 	/* Part 3: Initialize the character device */
981 	vdev->cdev = cdev_alloc();
982 	if (vdev->cdev == NULL) {
983 		ret = -ENOMEM;
984 		goto cleanup;
985 	}
986 	vdev->cdev->ops = &v4l2_fops;
987 	vdev->cdev->owner = owner;
988 	ret = cdev_add(vdev->cdev, MKDEV(VIDEO_MAJOR, vdev->minor), 1);
989 	if (ret < 0) {
990 		pr_err("%s: cdev_add failed\n", __func__);
991 		kfree(vdev->cdev);
992 		vdev->cdev = NULL;
993 		goto cleanup;
994 	}
995 
996 	/* Part 4: register the device with sysfs */
997 	vdev->dev.class = &video_class;
998 	vdev->dev.devt = MKDEV(VIDEO_MAJOR, vdev->minor);
999 	vdev->dev.parent = vdev->dev_parent;
1000 	dev_set_name(&vdev->dev, "%s%d", name_base, vdev->num);
1001 	ret = device_register(&vdev->dev);
1002 	if (ret < 0) {
1003 		pr_err("%s: device_register failed\n", __func__);
1004 		goto cleanup;
1005 	}
1006 	/* Register the release callback that will be called when the last
1007 	   reference to the device goes away. */
1008 	vdev->dev.release = v4l2_device_release;
1009 
1010 	if (nr != -1 && nr != vdev->num && warn_if_nr_in_use)
1011 		pr_warn("%s: requested %s%d, got %s\n", __func__,
1012 			name_base, nr, video_device_node_name(vdev));
1013 
1014 	/* Increase v4l2_device refcount */
1015 	v4l2_device_get(vdev->v4l2_dev);
1016 
1017 	/* Part 5: Register the entity. */
1018 	ret = video_register_media_controller(vdev);
1019 
1020 	/* Part 6: Activate this minor. The char device can now be used. */
1021 	set_bit(V4L2_FL_REGISTERED, &vdev->flags);
1022 
1023 	return 0;
1024 
1025 cleanup:
1026 	mutex_lock(&videodev_lock);
1027 	if (vdev->cdev)
1028 		cdev_del(vdev->cdev);
1029 	video_devices[vdev->minor] = NULL;
1030 	devnode_clear(vdev);
1031 	mutex_unlock(&videodev_lock);
1032 	/* Mark this video device as never having been registered. */
1033 	vdev->minor = -1;
1034 	return ret;
1035 }
1036 EXPORT_SYMBOL(__video_register_device);
1037 
1038 /**
1039  *	video_unregister_device - unregister a video4linux device
1040  *	@vdev: the device to unregister
1041  *
1042  *	This unregisters the passed device. Future open calls will
1043  *	be met with errors.
1044  */
1045 void video_unregister_device(struct video_device *vdev)
1046 {
1047 	/* Check if vdev was ever registered at all */
1048 	if (!vdev || !video_is_registered(vdev))
1049 		return;
1050 
1051 	mutex_lock(&videodev_lock);
1052 	/* This must be in a critical section to prevent a race with v4l2_open.
1053 	 * Once this bit has been cleared video_get may never be called again.
1054 	 */
1055 	clear_bit(V4L2_FL_REGISTERED, &vdev->flags);
1056 	mutex_unlock(&videodev_lock);
1057 	device_unregister(&vdev->dev);
1058 }
1059 EXPORT_SYMBOL(video_unregister_device);
1060 
1061 /*
1062  *	Initialise video for linux
1063  */
1064 static int __init videodev_init(void)
1065 {
1066 	dev_t dev = MKDEV(VIDEO_MAJOR, 0);
1067 	int ret;
1068 
1069 	pr_info("Linux video capture interface: v2.00\n");
1070 	ret = register_chrdev_region(dev, VIDEO_NUM_DEVICES, VIDEO_NAME);
1071 	if (ret < 0) {
1072 		pr_warn("videodev: unable to get major %d\n",
1073 				VIDEO_MAJOR);
1074 		return ret;
1075 	}
1076 
1077 	ret = class_register(&video_class);
1078 	if (ret < 0) {
1079 		unregister_chrdev_region(dev, VIDEO_NUM_DEVICES);
1080 		pr_warn("video_dev: class_register failed\n");
1081 		return -EIO;
1082 	}
1083 
1084 	return 0;
1085 }
1086 
1087 static void __exit videodev_exit(void)
1088 {
1089 	dev_t dev = MKDEV(VIDEO_MAJOR, 0);
1090 
1091 	class_unregister(&video_class);
1092 	unregister_chrdev_region(dev, VIDEO_NUM_DEVICES);
1093 }
1094 
1095 subsys_initcall(videodev_init);
1096 module_exit(videodev_exit)
1097 
1098 MODULE_AUTHOR("Alan Cox, Mauro Carvalho Chehab <mchehab@kernel.org>");
1099 MODULE_DESCRIPTION("Device registrar for Video4Linux drivers v2");
1100 MODULE_LICENSE("GPL");
1101 MODULE_ALIAS_CHARDEV_MAJOR(VIDEO_MAJOR);
1102