xref: /openbmc/linux/include/media/v4l2-device.h (revision b34e08d5)
1 /*
2     V4L2 device support header.
3 
4     Copyright (C) 2008  Hans Verkuil <hverkuil@xs4all.nl>
5 
6     This program is free software; you can redistribute it and/or modify
7     it under the terms of the GNU General Public License as published by
8     the Free Software Foundation; either version 2 of the License, or
9     (at your option) any later version.
10 
11     This program is distributed in the hope that it will be useful,
12     but WITHOUT ANY WARRANTY; without even the implied warranty of
13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14     GNU General Public License for more details.
15 
16     You should have received a copy of the GNU General Public License
17     along with this program; if not, write to the Free Software
18     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
19  */
20 
21 #ifndef _V4L2_DEVICE_H
22 #define _V4L2_DEVICE_H
23 
24 #include <media/media-device.h>
25 #include <media/v4l2-subdev.h>
26 #include <media/v4l2-dev.h>
27 
28 /* Each instance of a V4L2 device should create the v4l2_device struct,
29    either stand-alone or embedded in a larger struct.
30 
31    It allows easy access to sub-devices (see v4l2-subdev.h) and provides
32    basic V4L2 device-level support.
33  */
34 
35 #define V4L2_DEVICE_NAME_SIZE (20 + 16)
36 
37 struct v4l2_ctrl_handler;
38 
39 struct v4l2_device {
40 	/* dev->driver_data points to this struct.
41 	   Note: dev might be NULL if there is no parent device
42 	   as is the case with e.g. ISA devices. */
43 	struct device *dev;
44 #if defined(CONFIG_MEDIA_CONTROLLER)
45 	struct media_device *mdev;
46 #endif
47 	/* used to keep track of the registered subdevs */
48 	struct list_head subdevs;
49 	/* lock this struct; can be used by the driver as well if this
50 	   struct is embedded into a larger struct. */
51 	spinlock_t lock;
52 	/* unique device name, by default the driver name + bus ID */
53 	char name[V4L2_DEVICE_NAME_SIZE];
54 	/* notify callback called by some sub-devices. */
55 	void (*notify)(struct v4l2_subdev *sd,
56 			unsigned int notification, void *arg);
57 	/* The control handler. May be NULL. */
58 	struct v4l2_ctrl_handler *ctrl_handler;
59 	/* Device's priority state */
60 	struct v4l2_prio_state prio;
61 	/* BKL replacement mutex. Temporary solution only. */
62 	struct mutex ioctl_lock;
63 	/* Keep track of the references to this struct. */
64 	struct kref ref;
65 	/* Release function that is called when the ref count goes to 0. */
66 	void (*release)(struct v4l2_device *v4l2_dev);
67 };
68 
69 static inline void v4l2_device_get(struct v4l2_device *v4l2_dev)
70 {
71 	kref_get(&v4l2_dev->ref);
72 }
73 
74 int v4l2_device_put(struct v4l2_device *v4l2_dev);
75 
76 /* Initialize v4l2_dev and make dev->driver_data point to v4l2_dev.
77    dev may be NULL in rare cases (ISA devices). In that case you
78    must fill in the v4l2_dev->name field before calling this function. */
79 int __must_check v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev);
80 
81 /* Optional function to initialize the name field of struct v4l2_device using
82    the driver name and a driver-global atomic_t instance.
83    This function will increment the instance counter and returns the instance
84    value used in the name.
85 
86    Example:
87 
88    static atomic_t drv_instance = ATOMIC_INIT(0);
89 
90    ...
91 
92    instance = v4l2_device_set_name(&v4l2_dev, "foo", &drv_instance);
93 
94    The first time this is called the name field will be set to foo0 and
95    this function returns 0. If the name ends with a digit (e.g. cx18),
96    then the name will be set to cx18-0 since cx180 looks really odd. */
97 int v4l2_device_set_name(struct v4l2_device *v4l2_dev, const char *basename,
98 						atomic_t *instance);
99 
100 /* Set v4l2_dev->dev to NULL. Call when the USB parent disconnects.
101    Since the parent disappears this ensures that v4l2_dev doesn't have an
102    invalid parent pointer. */
103 void v4l2_device_disconnect(struct v4l2_device *v4l2_dev);
104 
105 /* Unregister all sub-devices and any other resources related to v4l2_dev. */
106 void v4l2_device_unregister(struct v4l2_device *v4l2_dev);
107 
108 /* Register a subdev with a v4l2 device. While registered the subdev module
109    is marked as in-use. An error is returned if the module is no longer
110    loaded when you attempt to register it. */
111 int __must_check v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
112 						struct v4l2_subdev *sd);
113 /* Unregister a subdev with a v4l2 device. Can also be called if the subdev
114    wasn't registered. In that case it will do nothing. */
115 void v4l2_device_unregister_subdev(struct v4l2_subdev *sd);
116 
117 /* Register device nodes for all subdev of the v4l2 device that are marked with
118  * the V4L2_SUBDEV_FL_HAS_DEVNODE flag.
119  */
120 int __must_check
121 v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev);
122 
123 /* Iterate over all subdevs. */
124 #define v4l2_device_for_each_subdev(sd, v4l2_dev)			\
125 	list_for_each_entry(sd, &(v4l2_dev)->subdevs, list)
126 
127 /* Call the specified callback for all subdevs matching the condition.
128    Ignore any errors. Note that you cannot add or delete a subdev
129    while walking the subdevs list. */
130 #define __v4l2_device_call_subdevs_p(v4l2_dev, sd, cond, o, f, args...)	\
131 	do { 								\
132 		list_for_each_entry((sd), &(v4l2_dev)->subdevs, list)	\
133 			if ((cond) && (sd)->ops->o && (sd)->ops->o->f)	\
134 				(sd)->ops->o->f((sd) , ##args);		\
135 	} while (0)
136 
137 #define __v4l2_device_call_subdevs(v4l2_dev, cond, o, f, args...)	\
138 	do {								\
139 		struct v4l2_subdev *__sd;				\
140 									\
141 		__v4l2_device_call_subdevs_p(v4l2_dev, __sd, cond, o,	\
142 						f , ##args);		\
143 	} while (0)
144 
145 /* Call the specified callback for all subdevs matching the condition.
146    If the callback returns an error other than 0 or -ENOIOCTLCMD, then
147    return with that error code. Note that you cannot add or delete a
148    subdev while walking the subdevs list. */
149 #define __v4l2_device_call_subdevs_until_err_p(v4l2_dev, sd, cond, o, f, args...) \
150 ({ 									\
151 	long __err = 0;							\
152 									\
153 	list_for_each_entry((sd), &(v4l2_dev)->subdevs, list) {		\
154 		if ((cond) && (sd)->ops->o && (sd)->ops->o->f)		\
155 			__err = (sd)->ops->o->f((sd) , ##args);		\
156 		if (__err && __err != -ENOIOCTLCMD)			\
157 			break; 						\
158 	} 								\
159 	(__err == -ENOIOCTLCMD) ? 0 : __err;				\
160 })
161 
162 #define __v4l2_device_call_subdevs_until_err(v4l2_dev, cond, o, f, args...) \
163 ({									\
164 	struct v4l2_subdev *__sd;					\
165 	__v4l2_device_call_subdevs_until_err_p(v4l2_dev, __sd, cond, o,	\
166 						f , ##args);		\
167 })
168 
169 /* Call the specified callback for all subdevs matching grp_id (if 0, then
170    match them all). Ignore any errors. Note that you cannot add or delete
171    a subdev while walking the subdevs list. */
172 #define v4l2_device_call_all(v4l2_dev, grpid, o, f, args...)		\
173 	do {								\
174 		struct v4l2_subdev *__sd;				\
175 									\
176 		__v4l2_device_call_subdevs_p(v4l2_dev, __sd,		\
177 			!(grpid) || __sd->grp_id == (grpid), o, f ,	\
178 			##args);					\
179 	} while (0)
180 
181 /* Call the specified callback for all subdevs matching grp_id (if 0, then
182    match them all). If the callback returns an error other than 0 or
183    -ENOIOCTLCMD, then return with that error code. Note that you cannot
184    add or delete a subdev while walking the subdevs list. */
185 #define v4l2_device_call_until_err(v4l2_dev, grpid, o, f, args...) 	\
186 ({									\
187 	struct v4l2_subdev *__sd;					\
188 	__v4l2_device_call_subdevs_until_err_p(v4l2_dev, __sd,		\
189 			!(grpid) || __sd->grp_id == (grpid), o, f ,	\
190 			##args);					\
191 })
192 
193 #define v4l2_device_has_op(v4l2_dev, o, f)				\
194 ({									\
195 	struct v4l2_subdev *__sd;					\
196 	bool __result = false;						\
197 	list_for_each_entry(__sd, &(v4l2_dev)->subdevs, list) {		\
198 		if (v4l2_subdev_has_op(__sd, o, f)) {			\
199 			__result = true;				\
200 			break;						\
201 		}							\
202 	}								\
203 	__result;							\
204 })
205 
206 #endif
207