xref: /openbmc/linux/include/media/v4l2-device.h (revision f125e2d4) 
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 all subdevs
178  *	of the v4l2 device that are marked with
179  *	the %V4L2_SUBDEV_FL_HAS_DEVNODE flag.
180  *
181  * @v4l2_dev: pointer to struct v4l2_device
182  */
183 int __must_check
184 v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev);
185 
186 /**
187  * v4l2_subdev_notify - Sends a notification to v4l2_device.
188  *
189  * @sd: pointer to &struct v4l2_subdev
190  * @notification: type of notification. Please notice that the notification
191  *	type is driver-specific.
192  * @arg: arguments for the notification. Those are specific to each
193  *	notification type.
194  */
195 static inline void v4l2_subdev_notify(struct v4l2_subdev *sd,
196 				      unsigned int notification, void *arg)
197 {
198 	if (sd && sd->v4l2_dev && sd->v4l2_dev->notify)
199 		sd->v4l2_dev->notify(sd, notification, arg);
200 }
201 
202 /**
203  * v4l2_device_supports_requests - Test if requests are supported.
204  *
205  * @v4l2_dev: pointer to struct v4l2_device
206  */
207 static inline bool v4l2_device_supports_requests(struct v4l2_device *v4l2_dev)
208 {
209 	return v4l2_dev->mdev && v4l2_dev->mdev->ops &&
210 	       v4l2_dev->mdev->ops->req_queue;
211 }
212 
213 /* Helper macros to iterate over all subdevs. */
214 
215 /**
216  * v4l2_device_for_each_subdev - Helper macro that interates over all
217  *	sub-devices of a given &v4l2_device.
218  *
219  * @sd: pointer that will be filled by the macro with all
220  *	&struct v4l2_subdev pointer used as an iterator by the loop.
221  * @v4l2_dev: &struct v4l2_device owning the sub-devices to iterate over.
222  *
223  * This macro iterates over all sub-devices owned by the @v4l2_dev device.
224  * It acts as a for loop iterator and executes the next statement with
225  * the @sd variable pointing to each sub-device in turn.
226  */
227 #define v4l2_device_for_each_subdev(sd, v4l2_dev)			\
228 	list_for_each_entry(sd, &(v4l2_dev)->subdevs, list)
229 
230 /**
231  * __v4l2_device_call_subdevs_p - Calls the specified operation for
232  *	all subdevs matching the condition.
233  *
234  * @v4l2_dev: &struct v4l2_device owning the sub-devices to iterate over.
235  * @sd: pointer that will be filled by the macro with all
236  *	&struct v4l2_subdev pointer used as an iterator by the loop.
237  * @cond: condition to be match
238  * @o: name of the element at &struct v4l2_subdev_ops that contains @f.
239  *     Each element there groups a set of operations functions.
240  * @f: operation function that will be called if @cond matches.
241  *	The operation functions are defined in groups, according to
242  *	each element at &struct v4l2_subdev_ops.
243  * @args...: arguments for @f.
244  *
245  * Ignore any errors.
246  *
247  * Note: subdevs cannot be added or deleted while walking
248  * the subdevs list.
249  */
250 #define __v4l2_device_call_subdevs_p(v4l2_dev, sd, cond, o, f, args...)	\
251 	do {								\
252 		list_for_each_entry((sd), &(v4l2_dev)->subdevs, list)	\
253 			if ((cond) && (sd)->ops->o && (sd)->ops->o->f)	\
254 				(sd)->ops->o->f((sd) , ##args);		\
255 	} while (0)
256 
257 /**
258  * __v4l2_device_call_subdevs - Calls the specified operation for
259  *	all subdevs matching the condition.
260  *
261  * @v4l2_dev: &struct v4l2_device owning the sub-devices to iterate over.
262  * @cond: condition to be match
263  * @o: name of the element at &struct v4l2_subdev_ops that contains @f.
264  *     Each element there groups a set of operations functions.
265  * @f: operation function that will be called if @cond matches.
266  *	The operation functions are defined in groups, according to
267  *	each element at &struct v4l2_subdev_ops.
268  * @args...: arguments for @f.
269  *
270  * Ignore any errors.
271  *
272  * Note: subdevs cannot be added or deleted while walking
273  * the subdevs list.
274  */
275 #define __v4l2_device_call_subdevs(v4l2_dev, cond, o, f, args...)	\
276 	do {								\
277 		struct v4l2_subdev *__sd;				\
278 									\
279 		__v4l2_device_call_subdevs_p(v4l2_dev, __sd, cond, o,	\
280 						f , ##args);		\
281 	} while (0)
282 
283 /**
284  * __v4l2_device_call_subdevs_until_err_p - Calls the specified operation for
285  *	all subdevs matching the condition.
286  *
287  * @v4l2_dev: &struct v4l2_device owning the sub-devices to iterate over.
288  * @sd: pointer that will be filled by the macro with all
289  *	&struct v4l2_subdev sub-devices associated with @v4l2_dev.
290  * @cond: condition to be match
291  * @o: name of the element at &struct v4l2_subdev_ops that contains @f.
292  *     Each element there groups a set of operations functions.
293  * @f: operation function that will be called if @cond matches.
294  *	The operation functions are defined in groups, according to
295  *	each element at &struct v4l2_subdev_ops.
296  * @args...: arguments for @f.
297  *
298  * Return:
299  *
300  * If the operation returns an error other than 0 or ``-ENOIOCTLCMD``
301  * for any subdevice, then abort and return with that error code, zero
302  * otherwise.
303  *
304  * Note: subdevs cannot be added or deleted while walking
305  * the subdevs list.
306  */
307 #define __v4l2_device_call_subdevs_until_err_p(v4l2_dev, sd, cond, o, f, args...) \
308 ({									\
309 	long __err = 0;							\
310 									\
311 	list_for_each_entry((sd), &(v4l2_dev)->subdevs, list) {		\
312 		if ((cond) && (sd)->ops->o && (sd)->ops->o->f)		\
313 			__err = (sd)->ops->o->f((sd) , ##args);		\
314 		if (__err && __err != -ENOIOCTLCMD)			\
315 			break;						\
316 	}								\
317 	(__err == -ENOIOCTLCMD) ? 0 : __err;				\
318 })
319 
320 /**
321  * __v4l2_device_call_subdevs_until_err - Calls the specified operation for
322  *	all subdevs matching the condition.
323  *
324  * @v4l2_dev: &struct v4l2_device owning the sub-devices to iterate over.
325  * @cond: condition to be match
326  * @o: name of the element at &struct v4l2_subdev_ops that contains @f.
327  *     Each element there groups a set of operations functions.
328  * @f: operation function that will be called if @cond matches.
329  *	The operation functions are defined in groups, according to
330  *	each element at &struct v4l2_subdev_ops.
331  * @args...: arguments for @f.
332  *
333  * Return:
334  *
335  * If the operation returns an error other than 0 or ``-ENOIOCTLCMD``
336  * for any subdevice, then abort and return with that error code,
337  * zero otherwise.
338  *
339  * Note: subdevs cannot be added or deleted while walking
340  * the subdevs list.
341  */
342 #define __v4l2_device_call_subdevs_until_err(v4l2_dev, cond, o, f, args...) \
343 ({									\
344 	struct v4l2_subdev *__sd;					\
345 	__v4l2_device_call_subdevs_until_err_p(v4l2_dev, __sd, cond, o,	\
346 						f , ##args);		\
347 })
348 
349 /**
350  * v4l2_device_call_all - Calls the specified operation for
351  *	all subdevs matching the &v4l2_subdev.grp_id, as assigned
352  *	by the bridge driver.
353  *
354  * @v4l2_dev: &struct v4l2_device owning the sub-devices to iterate over.
355  * @grpid: &struct v4l2_subdev->grp_id group ID to match.
356  *	    Use 0 to match them all.
357  * @o: name of the element at &struct v4l2_subdev_ops that contains @f.
358  *     Each element there groups a set of operations functions.
359  * @f: operation function that will be called if @cond matches.
360  *	The operation functions are defined in groups, according to
361  *	each element at &struct v4l2_subdev_ops.
362  * @args...: arguments for @f.
363  *
364  * Ignore any errors.
365  *
366  * Note: subdevs cannot be added or deleted while walking
367  * the subdevs list.
368  */
369 #define v4l2_device_call_all(v4l2_dev, grpid, o, f, args...)		\
370 	do {								\
371 		struct v4l2_subdev *__sd;				\
372 									\
373 		__v4l2_device_call_subdevs_p(v4l2_dev, __sd,		\
374 			(grpid) == 0 || __sd->grp_id == (grpid), o, f ,	\
375 			##args);					\
376 	} while (0)
377 
378 /**
379  * v4l2_device_call_until_err - Calls the specified operation for
380  *	all subdevs matching the &v4l2_subdev.grp_id, as assigned
381  *	by the bridge driver, until an error occurs.
382  *
383  * @v4l2_dev: &struct v4l2_device owning the sub-devices to iterate over.
384  * @grpid: &struct v4l2_subdev->grp_id group ID to match.
385  *	   Use 0 to match them all.
386  * @o: name of the element at &struct v4l2_subdev_ops that contains @f.
387  *     Each element there groups a set of operations functions.
388  * @f: operation function that will be called if @cond matches.
389  *	The operation functions are defined in groups, according to
390  *	each element at &struct v4l2_subdev_ops.
391  * @args...: arguments for @f.
392  *
393  * Return:
394  *
395  * If the operation returns an error other than 0 or ``-ENOIOCTLCMD``
396  * for any subdevice, then abort and return with that error code,
397  * zero otherwise.
398  *
399  * Note: subdevs cannot be added or deleted while walking
400  * the subdevs list.
401  */
402 #define v4l2_device_call_until_err(v4l2_dev, grpid, o, f, args...)	\
403 ({									\
404 	struct v4l2_subdev *__sd;					\
405 	__v4l2_device_call_subdevs_until_err_p(v4l2_dev, __sd,		\
406 			(grpid) == 0 || __sd->grp_id == (grpid), o, f ,	\
407 			##args);					\
408 })
409 
410 /**
411  * v4l2_device_mask_call_all - Calls the specified operation for
412  *	all subdevices where a group ID matches a specified bitmask.
413  *
414  * @v4l2_dev: &struct v4l2_device owning the sub-devices to iterate over.
415  * @grpmsk: bitmask to be checked against &struct v4l2_subdev->grp_id
416  *	    group ID to be matched. Use 0 to match them all.
417  * @o: name of the element at &struct v4l2_subdev_ops that contains @f.
418  *     Each element there groups a set of operations functions.
419  * @f: operation function that will be called if @cond matches.
420  *	The operation functions are defined in groups, according to
421  *	each element at &struct v4l2_subdev_ops.
422  * @args...: arguments for @f.
423  *
424  * Ignore any errors.
425  *
426  * Note: subdevs cannot be added or deleted while walking
427  * the subdevs list.
428  */
429 #define v4l2_device_mask_call_all(v4l2_dev, grpmsk, o, f, args...)	\
430 	do {								\
431 		struct v4l2_subdev *__sd;				\
432 									\
433 		__v4l2_device_call_subdevs_p(v4l2_dev, __sd,		\
434 			(grpmsk) == 0 || (__sd->grp_id & (grpmsk)), o,	\
435 			f , ##args);					\
436 	} while (0)
437 
438 /**
439  * v4l2_device_mask_call_until_err - Calls the specified operation for
440  *	all subdevices where a group ID matches a specified bitmask.
441  *
442  * @v4l2_dev: &struct v4l2_device owning the sub-devices to iterate over.
443  * @grpmsk: bitmask to be checked against &struct v4l2_subdev->grp_id
444  *	    group ID to be matched. Use 0 to match them all.
445  * @o: name of the element at &struct v4l2_subdev_ops that contains @f.
446  *     Each element there groups a set of operations functions.
447  * @f: operation function that will be called if @cond matches.
448  *	The operation functions are defined in groups, according to
449  *	each element at &struct v4l2_subdev_ops.
450  * @args...: arguments for @f.
451  *
452  * Return:
453  *
454  * If the operation returns an error other than 0 or ``-ENOIOCTLCMD``
455  * for any subdevice, then abort and return with that error code,
456  * zero otherwise.
457  *
458  * Note: subdevs cannot be added or deleted while walking
459  * the subdevs list.
460  */
461 #define v4l2_device_mask_call_until_err(v4l2_dev, grpmsk, o, f, args...) \
462 ({									\
463 	struct v4l2_subdev *__sd;					\
464 	__v4l2_device_call_subdevs_until_err_p(v4l2_dev, __sd,		\
465 			(grpmsk) == 0 || (__sd->grp_id & (grpmsk)), o,	\
466 			f , ##args);					\
467 })
468 
469 
470 /**
471  * v4l2_device_has_op - checks if any subdev with matching grpid has a
472  *	given ops.
473  *
474  * @v4l2_dev: &struct v4l2_device owning the sub-devices to iterate over.
475  * @grpid: &struct v4l2_subdev->grp_id group ID to match.
476  *	   Use 0 to match them all.
477  * @o: name of the element at &struct v4l2_subdev_ops that contains @f.
478  *     Each element there groups a set of operations functions.
479  * @f: operation function that will be called if @cond matches.
480  *	The operation functions are defined in groups, according to
481  *	each element at &struct v4l2_subdev_ops.
482  */
483 #define v4l2_device_has_op(v4l2_dev, grpid, o, f)			\
484 ({									\
485 	struct v4l2_subdev *__sd;					\
486 	bool __result = false;						\
487 	list_for_each_entry(__sd, &(v4l2_dev)->subdevs, list) {		\
488 		if ((grpid) && __sd->grp_id != (grpid))			\
489 			continue;					\
490 		if (v4l2_subdev_has_op(__sd, o, f)) {			\
491 			__result = true;				\
492 			break;						\
493 		}							\
494 	}								\
495 	__result;							\
496 })
497 
498 /**
499  * v4l2_device_mask_has_op - checks if any subdev with matching group
500  *	mask has a given ops.
501  *
502  * @v4l2_dev: &struct v4l2_device owning the sub-devices to iterate over.
503  * @grpmsk: bitmask to be checked against &struct v4l2_subdev->grp_id
504  *	    group ID to be matched. Use 0 to match them all.
505  * @o: name of the element at &struct v4l2_subdev_ops that contains @f.
506  *     Each element there groups a set of operations functions.
507  * @f: operation function that will be called if @cond matches.
508  *	The operation functions are defined in groups, according to
509  *	each element at &struct v4l2_subdev_ops.
510  */
511 #define v4l2_device_mask_has_op(v4l2_dev, grpmsk, o, f)			\
512 ({									\
513 	struct v4l2_subdev *__sd;					\
514 	bool __result = false;						\
515 	list_for_each_entry(__sd, &(v4l2_dev)->subdevs, list) {		\
516 		if ((grpmsk) && !(__sd->grp_id & (grpmsk)))		\
517 			continue;					\
518 		if (v4l2_subdev_has_op(__sd, o, f)) {			\
519 			__result = true;				\
520 			break;						\
521 		}							\
522 	}								\
523 	__result;							\
524 })
525 
526 #endif
527