1 /*
2  * Media device node
3  *
4  * Copyright (C) 2010 Nokia Corporation
5  *
6  * Contacts: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
7  *	     Sakari Ailus <sakari.ailus@iki.fi>
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 
43 struct media_file_operations {
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 
53 /**
54  * struct media_devnode - Media device node
55  * @parent:	parent device
56  * @minor:	device node minor number
57  * @flags:	flags, combination of the MEDIA_FLAG_* constants
58  *
59  * This structure represents a media-related device node.
60  *
61  * The @parent is a physical device. It must be set by core or device drivers
62  * before registering the node.
63  */
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 
84 int __must_check media_devnode_register(struct media_devnode *mdev);
85 void media_devnode_unregister(struct media_devnode *mdev);
86 
media_devnode_data(struct file * filp)87 static inline struct media_devnode *media_devnode_data(struct file *filp)
88 {
89 	return filp->private_data;
90 }
91 
media_devnode_is_registered(struct media_devnode * mdev)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 */
98