1 /* SPDX-License-Identifier: GPL-2.0-only */ <<
2 /* 1 /*
3 * Media device node 2 * Media device node
4 * 3 *
5 * Copyright (C) 2010 Nokia Corporation 4 * Copyright (C) 2010 Nokia Corporation
6 * 5 *
7 * Contacts: Laurent Pinchart <laurent.pinchar 6 * Contacts: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
8 * Sakari Ailus <sakari.ailus@iki.fi 7 * Sakari Ailus <sakari.ailus@iki.fi>
9 * 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 *
10 * -- 18 * --
11 * 19 *
12 * Common functions for media-related drivers 20 * Common functions for media-related drivers to register and unregister media
13 * device nodes. 21 * device nodes.
14 */ 22 */
15 23
16 #ifndef _MEDIA_DEVNODE_H 24 #ifndef _MEDIA_DEVNODE_H
17 #define _MEDIA_DEVNODE_H 25 #define _MEDIA_DEVNODE_H
18 26
19 #include <linux/poll.h> 27 #include <linux/poll.h>
20 #include <linux/fs.h> 28 #include <linux/fs.h>
21 #include <linux/device.h> 29 #include <linux/device.h>
22 #include <linux/cdev.h> 30 #include <linux/cdev.h>
23 31
24 struct media_device; 32 struct media_device;
25 33
26 /* 34 /*
27 * Flag to mark the media_devnode struct as re 35 * Flag to mark the media_devnode struct as registered. Drivers must not touch
28 * this flag directly, it will be set and clea 36 * this flag directly, it will be set and cleared by media_devnode_register and
29 * media_devnode_unregister. 37 * media_devnode_unregister.
30 */ 38 */
31 #define MEDIA_FLAG_REGISTERED 0 39 #define MEDIA_FLAG_REGISTERED 0
32 40
33 /** 41 /**
34 * struct media_file_operations - Media device 42 * struct media_file_operations - Media device file operations
35 * 43 *
36 * @owner: should be filled with %THIS_MODULE 44 * @owner: should be filled with %THIS_MODULE
37 * @read: pointer to the function that impleme 45 * @read: pointer to the function that implements read() syscall
38 * @write: pointer to the function that implem 46 * @write: pointer to the function that implements write() syscall
39 * @poll: pointer to the function that impleme 47 * @poll: pointer to the function that implements poll() syscall
40 * @ioctl: pointer to the function that implem 48 * @ioctl: pointer to the function that implements ioctl() syscall
41 * @compat_ioctl: pointer to the function that 49 * @compat_ioctl: pointer to the function that will handle 32 bits userspace
42 * calls to the ioctl() syscall on a Kern !! 50 * calls to the the ioctl() syscall on a Kernel compiled with 64 bits.
43 * @open: pointer to the function that impleme 51 * @open: pointer to the function that implements open() syscall
44 * @release: pointer to the function that will 52 * @release: pointer to the function that will release the resources allocated
45 * by the @open function. 53 * by the @open function.
46 */ 54 */
47 struct media_file_operations { 55 struct media_file_operations {
48 struct module *owner; 56 struct module *owner;
49 ssize_t (*read) (struct file *, char _ 57 ssize_t (*read) (struct file *, char __user *, size_t, loff_t *);
50 ssize_t (*write) (struct file *, const 58 ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *);
51 __poll_t (*poll) (struct file *, struc 59 __poll_t (*poll) (struct file *, struct poll_table_struct *);
52 long (*ioctl) (struct file *, unsigned 60 long (*ioctl) (struct file *, unsigned int, unsigned long);
53 long (*compat_ioctl) (struct file *, u 61 long (*compat_ioctl) (struct file *, unsigned int, unsigned long);
54 int (*open) (struct file *); 62 int (*open) (struct file *);
55 int (*release) (struct file *); 63 int (*release) (struct file *);
56 }; 64 };
57 65
58 /** 66 /**
59 * struct media_devnode - Media device node 67 * struct media_devnode - Media device node
60 * @media_dev: pointer to struct &media_devic 68 * @media_dev: pointer to struct &media_device
61 * @fops: pointer to struct &media_file_ 69 * @fops: pointer to struct &media_file_operations with media device ops
62 * @dev: pointer to struct &device cont 70 * @dev: pointer to struct &device containing the media controller device
63 * @cdev: struct cdev pointer character 71 * @cdev: struct cdev pointer character device
64 * @parent: parent device 72 * @parent: parent device
65 * @minor: device node minor number 73 * @minor: device node minor number
66 * @flags: flags, combination of the ``ME 74 * @flags: flags, combination of the ``MEDIA_FLAG_*`` constants
67 * @release: release callback called at the 75 * @release: release callback called at the end of ``media_devnode_release()``
68 * routine at media-device.c. 76 * routine at media-device.c.
69 * 77 *
70 * This structure represents a media-related d 78 * This structure represents a media-related device node.
71 * 79 *
72 * The @parent is a physical device. It must b 80 * The @parent is a physical device. It must be set by core or device drivers
73 * before registering the node. 81 * before registering the node.
74 */ 82 */
75 struct media_devnode { 83 struct media_devnode {
76 struct media_device *media_dev; 84 struct media_device *media_dev;
77 85
78 /* device ops */ 86 /* device ops */
79 const struct media_file_operations *fo 87 const struct media_file_operations *fops;
80 88
81 /* sysfs */ 89 /* sysfs */
82 struct device dev; /* med 90 struct device dev; /* media device */
83 struct cdev cdev; /* cha 91 struct cdev cdev; /* character device */
84 struct device *parent; /* dev 92 struct device *parent; /* device parent */
85 93
86 /* device info */ 94 /* device info */
87 int minor; 95 int minor;
88 unsigned long flags; /* Use 96 unsigned long flags; /* Use bitops to access flags */
89 97
90 /* callbacks */ 98 /* callbacks */
91 void (*release)(struct media_devnode * 99 void (*release)(struct media_devnode *devnode);
92 }; 100 };
93 101
94 /* dev to media_devnode */ 102 /* dev to media_devnode */
95 #define to_media_devnode(cd) container_of(cd, 103 #define to_media_devnode(cd) container_of(cd, struct media_devnode, dev)
96 104
97 /** 105 /**
98 * media_devnode_register - register a media d 106 * media_devnode_register - register a media device node
99 * 107 *
100 * @mdev: struct media_device we want to regis 108 * @mdev: struct media_device we want to register a device node
101 * @devnode: media device node structure we wa 109 * @devnode: media device node structure we want to register
102 * @owner: should be filled with %THIS_MODULE 110 * @owner: should be filled with %THIS_MODULE
103 * 111 *
104 * The registration code assigns minor numbers 112 * The registration code assigns minor numbers and registers the new device node
105 * with the kernel. An error is returned if no 113 * with the kernel. An error is returned if no free minor number can be found,
106 * or if the registration of the device node f 114 * or if the registration of the device node fails.
107 * 115 *
108 * Zero is returned on success. 116 * Zero is returned on success.
109 * 117 *
110 * Note that if the media_devnode_register cal 118 * Note that if the media_devnode_register call fails, the release() callback of
111 * the media_devnode structure is *not* called 119 * the media_devnode structure is *not* called, so the caller is responsible for
112 * freeing any data. 120 * freeing any data.
113 */ 121 */
114 int __must_check media_devnode_register(struct 122 int __must_check media_devnode_register(struct media_device *mdev,
115 struct 123 struct media_devnode *devnode,
116 struct 124 struct module *owner);
117 125
118 /** 126 /**
119 * media_devnode_unregister_prepare - clear th 127 * media_devnode_unregister_prepare - clear the media device node register bit
120 * @devnode: the device node to prepare for un 128 * @devnode: the device node to prepare for unregister
121 * 129 *
122 * This clears the passed device register bit. 130 * This clears the passed device register bit. Future open calls will be met
123 * with errors. Should be called before media_ 131 * with errors. Should be called before media_devnode_unregister() to avoid
124 * races with unregister and device file open 132 * races with unregister and device file open calls.
125 * 133 *
126 * This function can safely be called if the d 134 * This function can safely be called if the device node has never been
127 * registered or has already been unregistered 135 * registered or has already been unregistered.
128 */ 136 */
129 void media_devnode_unregister_prepare(struct m 137 void media_devnode_unregister_prepare(struct media_devnode *devnode);
130 138
131 /** 139 /**
132 * media_devnode_unregister - unregister a med 140 * media_devnode_unregister - unregister a media device node
133 * @devnode: the device node to unregister 141 * @devnode: the device node to unregister
134 * 142 *
135 * This unregisters the passed device. Future 143 * This unregisters the passed device. Future open calls will be met with
136 * errors. 144 * errors.
137 * 145 *
138 * Should be called after media_devnode_unregi 146 * Should be called after media_devnode_unregister_prepare()
139 */ 147 */
140 void media_devnode_unregister(struct media_dev 148 void media_devnode_unregister(struct media_devnode *devnode);
141 149
142 /** 150 /**
143 * media_devnode_data - returns a pointer to t 151 * media_devnode_data - returns a pointer to the &media_devnode
144 * 152 *
145 * @filp: pointer to struct &file 153 * @filp: pointer to struct &file
146 */ 154 */
147 static inline struct media_devnode *media_devn 155 static inline struct media_devnode *media_devnode_data(struct file *filp)
148 { 156 {
149 return filp->private_data; 157 return filp->private_data;
150 } 158 }
151 159
152 /** 160 /**
153 * media_devnode_is_registered - returns true 161 * media_devnode_is_registered - returns true if &media_devnode is registered;
154 * false otherwise. 162 * false otherwise.
155 * 163 *
156 * @devnode: pointer to struct &media_devnode. 164 * @devnode: pointer to struct &media_devnode.
157 * 165 *
158 * Note: If mdev is NULL, it also returns fals 166 * Note: If mdev is NULL, it also returns false.
159 */ 167 */
160 static inline int media_devnode_is_registered( 168 static inline int media_devnode_is_registered(struct media_devnode *devnode)
161 { 169 {
162 if (!devnode) 170 if (!devnode)
163 return false; 171 return false;
164 172
165 return test_bit(MEDIA_FLAG_REGISTERED, 173 return test_bit(MEDIA_FLAG_REGISTERED, &devnode->flags);
166 } 174 }
167 175
168 #endif /* _MEDIA_DEVNODE_H */ 176 #endif /* _MEDIA_DEVNODE_H */
169 177
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