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cf4b9211 LP |
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 | ||
75c7e295 MCC |
43 | /** |
44 | * struct media_file_operations - Media device file operations | |
45 | * | |
46 | * @owner: should be filled with %THIS_MODULE | |
47 | * @read: pointer to the function that implements read() syscall | |
48 | * @write: pointer to the function that implements write() syscall | |
49 | * @poll: pointer to the function that implements poll() syscall | |
50 | * @ioctl: pointer to the function that implements ioctl() syscall | |
51 | * @compat_ioctl: pointer to the function that will handle 32 bits userspace | |
52 | * calls to the the ioctl() syscall on a Kernel compiled with 64 bits. | |
53 | * @open: pointer to the function that implements open() syscall | |
54 | * @release: pointer to the function that will release the resources allocated | |
55 | * by the @open function. | |
56 | */ | |
cf4b9211 LP |
57 | struct media_file_operations { |
58 | struct module *owner; | |
59 | ssize_t (*read) (struct file *, char __user *, size_t, loff_t *); | |
60 | ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *); | |
61 | unsigned int (*poll) (struct file *, struct poll_table_struct *); | |
62 | long (*ioctl) (struct file *, unsigned int, unsigned long); | |
c6c1d50b | 63 | long (*compat_ioctl) (struct file *, unsigned int, unsigned long); |
cf4b9211 LP |
64 | int (*open) (struct file *); |
65 | int (*release) (struct file *); | |
66 | }; | |
67 | ||
68 | /** | |
69 | * struct media_devnode - Media device node | |
75c7e295 | 70 | * @fops: pointer to struct &media_file_operations with media device ops |
ec0255ca MCC |
71 | * @dev: struct device pointer for the media controller device |
72 | * @cdev: struct cdev pointer character device | |
cf4b9211 LP |
73 | * @parent: parent device |
74 | * @minor: device node minor number | |
75 | * @flags: flags, combination of the MEDIA_FLAG_* constants | |
ec0255ca | 76 | * @release: release callback called at the end of media_devnode_release() |
cf4b9211 LP |
77 | * |
78 | * This structure represents a media-related device node. | |
79 | * | |
80 | * The @parent is a physical device. It must be set by core or device drivers | |
81 | * before registering the node. | |
82 | */ | |
83 | struct media_devnode { | |
84 | /* device ops */ | |
85 | const struct media_file_operations *fops; | |
86 | ||
87 | /* sysfs */ | |
88 | struct device dev; /* media device */ | |
89 | struct cdev cdev; /* character device */ | |
90 | struct device *parent; /* device parent */ | |
91 | ||
92 | /* device info */ | |
93 | int minor; | |
94 | unsigned long flags; /* Use bitops to access flags */ | |
95 | ||
96 | /* callbacks */ | |
97 | void (*release)(struct media_devnode *mdev); | |
98 | }; | |
99 | ||
100 | /* dev to media_devnode */ | |
101 | #define to_media_devnode(cd) container_of(cd, struct media_devnode, dev) | |
102 | ||
fe3c565e MCC |
103 | /** |
104 | * media_devnode_register - register a media device node | |
105 | * | |
106 | * @mdev: media device node structure we want to register | |
107 | * @owner: should be filled with %THIS_MODULE | |
108 | * | |
109 | * The registration code assigns minor numbers and registers the new device node | |
110 | * with the kernel. An error is returned if no free minor number can be found, | |
111 | * or if the registration of the device node fails. | |
112 | * | |
113 | * Zero is returned on success. | |
114 | * | |
115 | * Note that if the media_devnode_register call fails, the release() callback of | |
116 | * the media_devnode structure is *not* called, so the caller is responsible for | |
117 | * freeing any data. | |
118 | */ | |
85de721c SA |
119 | int __must_check media_devnode_register(struct media_devnode *mdev, |
120 | struct module *owner); | |
fe3c565e MCC |
121 | |
122 | /** | |
123 | * media_devnode_unregister - unregister a media device node | |
124 | * @mdev: the device node to unregister | |
125 | * | |
126 | * This unregisters the passed device. Future open calls will be met with | |
127 | * errors. | |
128 | * | |
129 | * This function can safely be called if the device node has never been | |
130 | * registered or has already been unregistered. | |
131 | */ | |
cf4b9211 LP |
132 | void media_devnode_unregister(struct media_devnode *mdev); |
133 | ||
75c7e295 MCC |
134 | /** |
135 | * media_devnode_data - returns a pointer to the &media_devnode | |
136 | * | |
137 | * @filp: pointer to struct &file | |
138 | */ | |
cf4b9211 LP |
139 | static inline struct media_devnode *media_devnode_data(struct file *filp) |
140 | { | |
141 | return filp->private_data; | |
142 | } | |
143 | ||
75c7e295 MCC |
144 | /** |
145 | * media_devnode_is_registered - returns true if &media_devnode is registered; | |
146 | * false otherwise. | |
147 | * | |
148 | * @mdev: pointer to struct &media_devnode. | |
149 | */ | |
cf4b9211 LP |
150 | static inline int media_devnode_is_registered(struct media_devnode *mdev) |
151 | { | |
152 | return test_bit(MEDIA_FLAG_REGISTERED, &mdev->flags); | |
153 | } | |
154 | ||
155 | #endif /* _MEDIA_DEVNODE_H */ |