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media-devnode.h
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1 /*
2  * Media device node
3  *
4  * Copyright (C) 2010 Nokia Corporation
5  *
6  * Contacts: Laurent Pinchart <[email protected]>
7  * Sakari Ailus <[email protected]>
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License version 2 as
11  * published by the Free Software Foundation.
12  *
13  * This program is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16  * GNU General Public License for more details.
17  *
18  * You should have received a copy of the GNU General Public License
19  * along with this program; if not, write to the Free Software
20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
21  *
22  * --
23  *
24  * Common functions for media-related drivers to register and unregister media
25  * device nodes.
26  */
27 
28 #ifndef _MEDIA_DEVNODE_H
29 #define _MEDIA_DEVNODE_H
30 
31 #include <linux/poll.h>
32 #include <linux/fs.h>
33 #include <linux/device.h>
34 #include <linux/cdev.h>
35 
36 /*
37  * Flag to mark the media_devnode struct as registered. Drivers must not touch
38  * this flag directly, it will be set and cleared by media_devnode_register and
39  * media_devnode_unregister.
40  */
41 #define MEDIA_FLAG_REGISTERED 0
42 
44  struct module *owner;
45  ssize_t (*read) (struct file *, char __user *, size_t, loff_t *);
46  ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *);
47  unsigned int (*poll) (struct file *, struct poll_table_struct *);
48  long (*ioctl) (struct file *, unsigned int, unsigned long);
49  int (*open) (struct file *);
50  int (*release) (struct file *);
51 };
52 
64 struct media_devnode {
65  /* device ops */
66  const struct media_file_operations *fops;
67 
68  /* sysfs */
69  struct device dev; /* media device */
70  struct cdev cdev; /* character device */
71  struct device *parent; /* device parent */
72 
73  /* device info */
74  int minor;
75  unsigned long flags; /* Use bitops to access flags */
76 
77  /* callbacks */
78  void (*release)(struct media_devnode *mdev);
79 };
80 
81 /* dev to media_devnode */
82 #define to_media_devnode(cd) container_of(cd, struct media_devnode, dev)
83 
85 void media_devnode_unregister(struct media_devnode *mdev);
86 
87 static inline struct media_devnode *media_devnode_data(struct file *filp)
88 {
89  return filp->private_data;
90 }
91 
92 static inline int media_devnode_is_registered(struct media_devnode *mdev)
93 {
94  return test_bit(MEDIA_FLAG_REGISTERED, &mdev->flags);
95 }
96 
97 #endif /* _MEDIA_DEVNODE_H */