xref: /linux/include/media/v4l2-device.h (revision 26fbb4c8c7c3ee9a4c3b4de555a8587b5a19154e) 
1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /*
3     V4L2 device support header.
4 
5     Copyright (C) 2008  Hans Verkuil <hverkuil@xs4all.nl>
6 
7  */
8 
9 #ifndef _V4L2_DEVICE_H
10 #define _V4L2_DEVICE_H
11 
12 #include <media/media-device.h>
13 #include <media/v4l2-subdev.h>
14 #include <media/v4l2-dev.h>
15 
16 #define V4L2_DEVICE_NAME_SIZE (20 + 16)
17 
18 struct v4l2_ctrl_handler;
19 
20 /**
21  * struct v4l2_device - main struct to for V4L2 device drivers
22  *
23  * @dev: pointer to struct device.
24  * @mdev: pointer to struct media_device, may be NULL.
25  * @subdevs: used to keep track of the registered subdevs
26  * @lock: lock this struct; can be used by the driver as well
27  *	if this struct is embedded into a larger struct.
28  * @name: unique device name, by default the driver name + bus ID
29  * @notify: notify operation called by some sub-devices.
30  * @ctrl_handler: The control handler. May be %NULL.
31  * @prio: Device's priority state
32  * @ref: Keep track of the references to this struct.
33  * @release: Release function that is called when the ref count
34  *	goes to 0.
35  *
36  * Each instance of a V4L2 device should create the v4l2_device struct,
37  * either stand-alone or embedded in a larger struct.
38  *
39  * It allows easy access to sub-devices (see v4l2-subdev.h) and provides
40  * basic V4L2 device-level support.
41  *
42  * .. note::
43  *
44  *    #) @dev->driver_data points to this struct.
45  *    #) @dev might be %NULL if there is no parent device
46  */
47 struct v4l2_device {
48 	struct device *dev;
49 	struct media_device *mdev;
50 	struct list_head subdevs;
51 	spinlock_t lock;
52 	char name[V4L2_DEVICE_NAME_SIZE];
53 	void (*notify)(struct v4l2_subdev *sd,
54 			unsigned int notification, void *arg);
55 	struct v4l2_ctrl_handler *ctrl_handler;
56 	struct v4l2_prio_state prio;
57 	struct kref ref;
58 	void (*release)(struct v4l2_device *v4l2_dev);
59 };
60 
61 /**
62  * v4l2_device_get - gets a V4L2 device reference
63  *
64  * @v4l2_dev: pointer to struct &v4l2_device
65  *
66  * This is an ancillary routine meant to increment the usage for the
67  * struct &v4l2_device pointed by @v4l2_dev.
68  */
69 static inline void v4l2_device_get(struct v4l2_device *v4l2_dev)
70 {
71 	kref_get(&v4l2_dev->ref);
72 }
73 
74 /**
75  * v4l2_device_put - puts a V4L2 device reference
76  *
77  * @v4l2_dev: pointer to struct &v4l2_device
78  *
79  * This is an ancillary routine meant to decrement the usage for the
80  * struct &v4l2_device pointed by @v4l2_dev.
81  */
82 int v4l2_device_put(struct v4l2_device *v4l2_dev);
83 
84 /**
85  * v4l2_device_register - Initialize v4l2_dev and make @dev->driver_data
86  *	point to @v4l2_dev.
87  *
88  * @dev: pointer to struct &device
89  * @v4l2_dev: pointer to struct &v4l2_device
90  *
91  * .. note::
92  *	@dev may be %NULL in rare cases (ISA devices).
93  *	In such case the caller must fill in the @v4l2_dev->name field
94  *	before calling this function.
95  */
96 int __must_check v4l2_device_register(struct device *dev,
97 				      struct v4l2_device *v4l2_dev);
98 
99 /**
100  * v4l2_device_set_name - Optional function to initialize the
101  *	name field of struct &v4l2_device
102  *
103  * @v4l2_dev: pointer to struct &v4l2_device
104  * @basename: base name for the device name
105  * @instance: pointer to a static atomic_t var with the instance usage for
106  *	the device driver.
107  *
108  * v4l2_device_set_name() initializes the name field of struct &v4l2_device
109  * using the driver name and a driver-global atomic_t instance.
110  *
111  * This function will increment the instance counter and returns the
112  * instance value used in the name.
113  *
114  * Example:
115  *
116  *   static atomic_t drv_instance = ATOMIC_INIT(0);
117  *
118  *   ...
119  *
120  *   instance = v4l2_device_set_name(&\ v4l2_dev, "foo", &\ drv_instance);
121  *
122  * The first time this is called the name field will be set to foo0 and
123  * this function returns 0. If the name ends with a digit (e.g. cx18),
124  * then the name will be set to cx18-0 since cx180 would look really odd.
125  */
126 int v4l2_device_set_name(struct v4l2_device *v4l2_dev, const char *basename,
127 			 atomic_t *instance);
128 
129 /**
130  * v4l2_device_disconnect - Change V4L2 device state to disconnected.
131  *
132  * @v4l2_dev: pointer to struct v4l2_device
133  *
134  * Should be called when the USB parent disconnects.
135  * Since the parent disappears, this ensures that @v4l2_dev doesn't have
136  * an invalid parent pointer.
137  *
138  * .. note:: This function sets @v4l2_dev->dev to NULL.
139  */
140 void v4l2_device_disconnect(struct v4l2_device *v4l2_dev);
141 
142 /**
143  *  v4l2_device_unregister - Unregister all sub-devices and any other
144  *	 resources related to @v4l2_dev.
145  *
146  * @v4l2_dev: pointer to struct v4l2_device
147  */
148 void v4l2_device_unregister(struct v4l2_device *v4l2_dev);
149 
150 /**
151  * v4l2_device_register_subdev - Registers a subdev with a v4l2 device.
152  *
153  * @v4l2_dev: pointer to struct &v4l2_device
154  * @sd: pointer to &struct v4l2_subdev
155  *
156  * While registered, the subdev module is marked as in-use.
157  *
158  * An error is returned if the module is no longer loaded on any attempts
159  * to register it.
160  */
161 int __must_check v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
162 					     struct v4l2_subdev *sd);
163 
164 /**
165  * v4l2_device_unregister_subdev - Unregisters a subdev with a v4l2 device.
166  *
167  * @sd: pointer to &struct v4l2_subdev
168  *
169  * .. note ::
170  *
171  *	Can also be called if the subdev wasn't registered. In such
172  *	case, it will do nothing.
173  */
174 void v4l2_device_unregister_subdev(struct v4l2_subdev *sd);
175 
176 /**
177  * __v4l2_device_register_subdev_nodes - Registers device nodes for
178  *      all subdevs of the v4l2 device that are marked with the
179  *      %V4L2_SUBDEV_FL_HAS_DEVNODE flag.
180  *
181  * @v4l2_dev: pointer to struct v4l2_device
182  * @read_only: subdevices read-only flag. True to register the subdevices
183  *	device nodes in read-only mode, false to allow full access to the
184  *	subdevice userspace API.
185  */
186 int __must_check
187 __v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev,
188 				    bool read_only);
189 
190 /**
191  * v4l2_device_register_subdev_nodes - Registers subdevices device nodes with
192  *	unrestricted access to the subdevice userspace operations
193  *
194  * Internally calls __v4l2_device_register_subdev_nodes(). See its documentation
195  * for more details.
196  *
197  * @v4l2_dev: pointer to struct v4l2_device
198  */
199 static inline int __must_check
200 v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev)
201 {
202 #if defined(CONFIG_VIDEO_V4L2_SUBDEV_API)
203 	return __v4l2_device_register_subdev_nodes(v4l2_dev, false);
204 #else
205 	return 0;
206 #endif
207 }
208 
209 /**
210  * v4l2_device_register_ro_subdev_nodes - Registers subdevices device nodes
211  *	in read-only mode
212  *
213  * Internally calls __v4l2_device_register_subdev_nodes(). See its documentation
214  * for more details.
215  *
216  * @v4l2_dev: pointer to struct v4l2_device
217  */
218 static inline int __must_check
219 v4l2_device_register_ro_subdev_nodes(struct v4l2_device *v4l2_dev)
220 {
221 #if defined(CONFIG_VIDEO_V4L2_SUBDEV_API)
222 	return __v4l2_device_register_subdev_nodes(v4l2_dev, true);
223 #else
224 	return 0;
225 #endif
226 }
227 
228 /**
229  * v4l2_subdev_notify - Sends a notification to v4l2_device.
230  *
231  * @sd: pointer to &struct v4l2_subdev
232  * @notification: type of notification. Please notice that the notification
233  *	type is driver-specific.
234  * @arg: arguments for the notification. Those are specific to each
235  *	notification type.
236  */
237 static inline void v4l2_subdev_notify(struct v4l2_subdev *sd,
238 				      unsigned int notification, void *arg)
239 {
240 	if (sd && sd->v4l2_dev && sd->v4l2_dev->notify)
241 		sd->v4l2_dev->notify(sd, notification, arg);
242 }
243 
244 /**
245  * v4l2_device_supports_requests - Test if requests are supported.
246  *
247  * @v4l2_dev: pointer to struct v4l2_device
248  */
249 static inline bool v4l2_device_supports_requests(struct v4l2_device *v4l2_dev)
250 {
251 	return v4l2_dev->mdev && v4l2_dev->mdev->ops &&
252 	       v4l2_dev->mdev->ops->req_queue;
253 }
254 
255 /* Helper macros to iterate over all subdevs. */
256 
257 /**
258  * v4l2_device_for_each_subdev - Helper macro that interates over all
259  *	sub-devices of a given &v4l2_device.
260  *
261  * @sd: pointer that will be filled by the macro with all
262  *	&struct v4l2_subdev pointer used as an iterator by the loop.
263  * @v4l2_dev: &struct v4l2_device owning the sub-devices to iterate over.
264  *
265  * This macro iterates over all sub-devices owned by the @v4l2_dev device.
266  * It acts as a for loop iterator and executes the next statement with
267  * the @sd variable pointing to each sub-device in turn.
268  */
269 #define v4l2_device_for_each_subdev(sd, v4l2_dev)			\
270 	list_for_each_entry(sd, &(v4l2_dev)->subdevs, list)
271 
272 /**
273  * __v4l2_device_call_subdevs_p - Calls the specified operation for
274  *	all subdevs matching the condition.
275  *
276  * @v4l2_dev: &struct v4l2_device owning the sub-devices to iterate over.
277  * @sd: pointer that will be filled by the macro with all
278  *	&struct v4l2_subdev pointer used as an iterator by the loop.
279  * @cond: condition to be match
280  * @o: name of the element at &struct v4l2_subdev_ops that contains @f.
281  *     Each element there groups a set of operations functions.
282  * @f: operation function that will be called if @cond matches.
283  *	The operation functions are defined in groups, according to
284  *	each element at &struct v4l2_subdev_ops.
285  * @args: arguments for @f.
286  *
287  * Ignore any errors.
288  *
289  * Note: subdevs cannot be added or deleted while walking
290  * the subdevs list.
291  */
292 #define __v4l2_device_call_subdevs_p(v4l2_dev, sd, cond, o, f, args...)	\
293 	do {								\
294 		list_for_each_entry((sd), &(v4l2_dev)->subdevs, list)	\
295 			if ((cond) && (sd)->ops->o && (sd)->ops->o->f)	\
296 				(sd)->ops->o->f((sd) , ##args);		\
297 	} while (0)
298 
299 /**
300  * __v4l2_device_call_subdevs - Calls the specified operation for
301  *	all subdevs matching the condition.
302  *
303  * @v4l2_dev: &struct v4l2_device owning the sub-devices to iterate over.
304  * @cond: condition to be match
305  * @o: name of the element at &struct v4l2_subdev_ops that contains @f.
306  *     Each element there groups a set of operations functions.
307  * @f: operation function that will be called if @cond matches.
308  *	The operation functions are defined in groups, according to
309  *	each element at &struct v4l2_subdev_ops.
310  * @args: arguments for @f.
311  *
312  * Ignore any errors.
313  *
314  * Note: subdevs cannot be added or deleted while walking
315  * the subdevs list.
316  */
317 #define __v4l2_device_call_subdevs(v4l2_dev, cond, o, f, args...)	\
318 	do {								\
319 		struct v4l2_subdev *__sd;				\
320 									\
321 		__v4l2_device_call_subdevs_p(v4l2_dev, __sd, cond, o,	\
322 						f , ##args);		\
323 	} while (0)
324 
325 /**
326  * __v4l2_device_call_subdevs_until_err_p - Calls the specified operation for
327  *	all subdevs matching the condition.
328  *
329  * @v4l2_dev: &struct v4l2_device owning the sub-devices to iterate over.
330  * @sd: pointer that will be filled by the macro with all
331  *	&struct v4l2_subdev sub-devices associated with @v4l2_dev.
332  * @cond: condition to be match
333  * @o: name of the element at &struct v4l2_subdev_ops that contains @f.
334  *     Each element there groups a set of operations functions.
335  * @f: operation function that will be called if @cond matches.
336  *	The operation functions are defined in groups, according to
337  *	each element at &struct v4l2_subdev_ops.
338  * @args: arguments for @f.
339  *
340  * Return:
341  *
342  * If the operation returns an error other than 0 or ``-ENOIOCTLCMD``
343  * for any subdevice, then abort and return with that error code, zero
344  * otherwise.
345  *
346  * Note: subdevs cannot be added or deleted while walking
347  * the subdevs list.
348  */
349 #define __v4l2_device_call_subdevs_until_err_p(v4l2_dev, sd, cond, o, f, args...) \
350 ({									\
351 	long __err = 0;							\
352 									\
353 	list_for_each_entry((sd), &(v4l2_dev)->subdevs, list) {		\
354 		if ((cond) && (sd)->ops->o && (sd)->ops->o->f)		\
355 			__err = (sd)->ops->o->f((sd) , ##args);		\
356 		if (__err && __err != -ENOIOCTLCMD)			\
357 			break;						\
358 	}								\
359 	(__err == -ENOIOCTLCMD) ? 0 : __err;				\
360 })
361 
362 /**
363  * __v4l2_device_call_subdevs_until_err - Calls the specified operation for
364  *	all subdevs matching the condition.
365  *
366  * @v4l2_dev: &struct v4l2_device owning the sub-devices to iterate over.
367  * @cond: condition to be match
368  * @o: name of the element at &struct v4l2_subdev_ops that contains @f.
369  *     Each element there groups a set of operations functions.
370  * @f: operation function that will be called if @cond matches.
371  *	The operation functions are defined in groups, according to
372  *	each element at &struct v4l2_subdev_ops.
373  * @args: arguments for @f.
374  *
375  * Return:
376  *
377  * If the operation returns an error other than 0 or ``-ENOIOCTLCMD``
378  * for any subdevice, then abort and return with that error code,
379  * zero otherwise.
380  *
381  * Note: subdevs cannot be added or deleted while walking
382  * the subdevs list.
383  */
384 #define __v4l2_device_call_subdevs_until_err(v4l2_dev, cond, o, f, args...) \
385 ({									\
386 	struct v4l2_subdev *__sd;					\
387 	__v4l2_device_call_subdevs_until_err_p(v4l2_dev, __sd, cond, o,	\
388 						f , ##args);		\
389 })
390 
391 /**
392  * v4l2_device_call_all - Calls the specified operation for
393  *	all subdevs matching the &v4l2_subdev.grp_id, as assigned
394  *	by the bridge driver.
395  *
396  * @v4l2_dev: &struct v4l2_device owning the sub-devices to iterate over.
397  * @grpid: &struct v4l2_subdev->grp_id group ID to match.
398  *	    Use 0 to match them all.
399  * @o: name of the element at &struct v4l2_subdev_ops that contains @f.
400  *     Each element there groups a set of operations functions.
401  * @f: operation function that will be called if @cond matches.
402  *	The operation functions are defined in groups, according to
403  *	each element at &struct v4l2_subdev_ops.
404  * @args: arguments for @f.
405  *
406  * Ignore any errors.
407  *
408  * Note: subdevs cannot be added or deleted while walking
409  * the subdevs list.
410  */
411 #define v4l2_device_call_all(v4l2_dev, grpid, o, f, args...)		\
412 	do {								\
413 		struct v4l2_subdev *__sd;				\
414 									\
415 		__v4l2_device_call_subdevs_p(v4l2_dev, __sd,		\
416 			(grpid) == 0 || __sd->grp_id == (grpid), o, f ,	\
417 			##args);					\
418 	} while (0)
419 
420 /**
421  * v4l2_device_call_until_err - Calls the specified operation for
422  *	all subdevs matching the &v4l2_subdev.grp_id, as assigned
423  *	by the bridge driver, until an error occurs.
424  *
425  * @v4l2_dev: &struct v4l2_device owning the sub-devices to iterate over.
426  * @grpid: &struct v4l2_subdev->grp_id group ID to match.
427  *	   Use 0 to match them all.
428  * @o: name of the element at &struct v4l2_subdev_ops that contains @f.
429  *     Each element there groups a set of operations functions.
430  * @f: operation function that will be called if @cond matches.
431  *	The operation functions are defined in groups, according to
432  *	each element at &struct v4l2_subdev_ops.
433  * @args: arguments for @f.
434  *
435  * Return:
436  *
437  * If the operation returns an error other than 0 or ``-ENOIOCTLCMD``
438  * for any subdevice, then abort and return with that error code,
439  * zero otherwise.
440  *
441  * Note: subdevs cannot be added or deleted while walking
442  * the subdevs list.
443  */
444 #define v4l2_device_call_until_err(v4l2_dev, grpid, o, f, args...)	\
445 ({									\
446 	struct v4l2_subdev *__sd;					\
447 	__v4l2_device_call_subdevs_until_err_p(v4l2_dev, __sd,		\
448 			(grpid) == 0 || __sd->grp_id == (grpid), o, f ,	\
449 			##args);					\
450 })
451 
452 /**
453  * v4l2_device_mask_call_all - Calls the specified operation for
454  *	all subdevices where a group ID matches a specified bitmask.
455  *
456  * @v4l2_dev: &struct v4l2_device owning the sub-devices to iterate over.
457  * @grpmsk: bitmask to be checked against &struct v4l2_subdev->grp_id
458  *	    group ID to be matched. Use 0 to match them all.
459  * @o: name of the element at &struct v4l2_subdev_ops that contains @f.
460  *     Each element there groups a set of operations functions.
461  * @f: operation function that will be called if @cond matches.
462  *	The operation functions are defined in groups, according to
463  *	each element at &struct v4l2_subdev_ops.
464  * @args: arguments for @f.
465  *
466  * Ignore any errors.
467  *
468  * Note: subdevs cannot be added or deleted while walking
469  * the subdevs list.
470  */
471 #define v4l2_device_mask_call_all(v4l2_dev, grpmsk, o, f, args...)	\
472 	do {								\
473 		struct v4l2_subdev *__sd;				\
474 									\
475 		__v4l2_device_call_subdevs_p(v4l2_dev, __sd,		\
476 			(grpmsk) == 0 || (__sd->grp_id & (grpmsk)), o,	\
477 			f , ##args);					\
478 	} while (0)
479 
480 /**
481  * v4l2_device_mask_call_until_err - Calls the specified operation for
482  *	all subdevices where a group ID matches a specified bitmask.
483  *
484  * @v4l2_dev: &struct v4l2_device owning the sub-devices to iterate over.
485  * @grpmsk: bitmask to be checked against &struct v4l2_subdev->grp_id
486  *	    group ID to be matched. Use 0 to match them all.
487  * @o: name of the element at &struct v4l2_subdev_ops that contains @f.
488  *     Each element there groups a set of operations functions.
489  * @f: operation function that will be called if @cond matches.
490  *	The operation functions are defined in groups, according to
491  *	each element at &struct v4l2_subdev_ops.
492  * @args: arguments for @f.
493  *
494  * Return:
495  *
496  * If the operation returns an error other than 0 or ``-ENOIOCTLCMD``
497  * for any subdevice, then abort and return with that error code,
498  * zero otherwise.
499  *
500  * Note: subdevs cannot be added or deleted while walking
501  * the subdevs list.
502  */
503 #define v4l2_device_mask_call_until_err(v4l2_dev, grpmsk, o, f, args...) \
504 ({									\
505 	struct v4l2_subdev *__sd;					\
506 	__v4l2_device_call_subdevs_until_err_p(v4l2_dev, __sd,		\
507 			(grpmsk) == 0 || (__sd->grp_id & (grpmsk)), o,	\
508 			f , ##args);					\
509 })
510 
511 
512 /**
513  * v4l2_device_has_op - checks if any subdev with matching grpid has a
514  *	given ops.
515  *
516  * @v4l2_dev: &struct v4l2_device owning the sub-devices to iterate over.
517  * @grpid: &struct v4l2_subdev->grp_id group ID to match.
518  *	   Use 0 to match them all.
519  * @o: name of the element at &struct v4l2_subdev_ops that contains @f.
520  *     Each element there groups a set of operations functions.
521  * @f: operation function that will be called if @cond matches.
522  *	The operation functions are defined in groups, according to
523  *	each element at &struct v4l2_subdev_ops.
524  */
525 #define v4l2_device_has_op(v4l2_dev, grpid, o, f)			\
526 ({									\
527 	struct v4l2_subdev *__sd;					\
528 	bool __result = false;						\
529 	list_for_each_entry(__sd, &(v4l2_dev)->subdevs, list) {		\
530 		if ((grpid) && __sd->grp_id != (grpid))			\
531 			continue;					\
532 		if (v4l2_subdev_has_op(__sd, o, f)) {			\
533 			__result = true;				\
534 			break;						\
535 		}							\
536 	}								\
537 	__result;							\
538 })
539 
540 /**
541  * v4l2_device_mask_has_op - checks if any subdev with matching group
542  *	mask has a given ops.
543  *
544  * @v4l2_dev: &struct v4l2_device owning the sub-devices to iterate over.
545  * @grpmsk: bitmask to be checked against &struct v4l2_subdev->grp_id
546  *	    group ID to be matched. Use 0 to match them all.
547  * @o: name of the element at &struct v4l2_subdev_ops that contains @f.
548  *     Each element there groups a set of operations functions.
549  * @f: operation function that will be called if @cond matches.
550  *	The operation functions are defined in groups, according to
551  *	each element at &struct v4l2_subdev_ops.
552  */
553 #define v4l2_device_mask_has_op(v4l2_dev, grpmsk, o, f)			\
554 ({									\
555 	struct v4l2_subdev *__sd;					\
556 	bool __result = false;						\
557 	list_for_each_entry(__sd, &(v4l2_dev)->subdevs, list) {		\
558 		if ((grpmsk) && !(__sd->grp_id & (grpmsk)))		\
559 			continue;					\
560 		if (v4l2_subdev_has_op(__sd, o, f)) {			\
561 			__result = true;				\
562 			break;						\
563 		}							\
564 	}								\
565 	__result;							\
566 })
567 
568 #endif
569