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Laurent Pinchartcf4b9212009-12-09 08:39:56 -03001/*
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
Mauro Carvalho Chehaba087ce72016-04-27 19:28:26 -030036struct media_device;
37
Laurent Pinchartcf4b9212009-12-09 08:39:56 -030038/*
39 * Flag to mark the media_devnode struct as registered. Drivers must not touch
40 * this flag directly, it will be set and cleared by media_devnode_register and
41 * media_devnode_unregister.
42 */
43#define MEDIA_FLAG_REGISTERED 0
44
Mauro Carvalho Chehab75c7e292015-12-13 09:00:00 -020045/**
46 * struct media_file_operations - Media device file operations
47 *
48 * @owner: should be filled with %THIS_MODULE
49 * @read: pointer to the function that implements read() syscall
50 * @write: pointer to the function that implements write() syscall
51 * @poll: pointer to the function that implements poll() syscall
52 * @ioctl: pointer to the function that implements ioctl() syscall
53 * @compat_ioctl: pointer to the function that will handle 32 bits userspace
54 * calls to the the ioctl() syscall on a Kernel compiled with 64 bits.
55 * @open: pointer to the function that implements open() syscall
56 * @release: pointer to the function that will release the resources allocated
57 * by the @open function.
58 */
Laurent Pinchartcf4b9212009-12-09 08:39:56 -030059struct media_file_operations {
60 struct module *owner;
61 ssize_t (*read) (struct file *, char __user *, size_t, loff_t *);
62 ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *);
63 unsigned int (*poll) (struct file *, struct poll_table_struct *);
64 long (*ioctl) (struct file *, unsigned int, unsigned long);
Sakari Ailusc6c1d502013-01-22 12:27:55 -030065 long (*compat_ioctl) (struct file *, unsigned int, unsigned long);
Laurent Pinchartcf4b9212009-12-09 08:39:56 -030066 int (*open) (struct file *);
67 int (*release) (struct file *);
68};
69
70/**
71 * struct media_devnode - Media device node
Mauro Carvalho Chehab0db5c792016-06-16 08:04:40 -030072 * @media_dev: pointer to struct &media_device
Mauro Carvalho Chehab75c7e292015-12-13 09:00:00 -020073 * @fops: pointer to struct &media_file_operations with media device ops
Mauro Carvalho Chehab0db5c792016-06-16 08:04:40 -030074 * @dev: pointer to struct &device containing the media controller device
Mauro Carvalho Chehabec0255c2015-08-22 04:45:03 -030075 * @cdev: struct cdev pointer character device
Laurent Pinchartcf4b9212009-12-09 08:39:56 -030076 * @parent: parent device
77 * @minor: device node minor number
78 * @flags: flags, combination of the MEDIA_FLAG_* constants
Mauro Carvalho Chehabec0255c2015-08-22 04:45:03 -030079 * @release: release callback called at the end of media_devnode_release()
Laurent Pinchartcf4b9212009-12-09 08:39:56 -030080 *
81 * This structure represents a media-related device node.
82 *
83 * The @parent is a physical device. It must be set by core or device drivers
84 * before registering the node.
85 */
86struct media_devnode {
Mauro Carvalho Chehaba087ce72016-04-27 19:28:26 -030087 struct media_device *media_dev;
88
Laurent Pinchartcf4b9212009-12-09 08:39:56 -030089 /* device ops */
90 const struct media_file_operations *fops;
91
92 /* sysfs */
93 struct device dev; /* media device */
94 struct cdev cdev; /* character device */
95 struct device *parent; /* device parent */
96
97 /* device info */
98 int minor;
99 unsigned long flags; /* Use bitops to access flags */
100
101 /* callbacks */
Mauro Carvalho Chehab163f1e92016-03-23 11:22:57 -0300102 void (*release)(struct media_devnode *devnode);
Laurent Pinchartcf4b9212009-12-09 08:39:56 -0300103};
104
105/* dev to media_devnode */
106#define to_media_devnode(cd) container_of(cd, struct media_devnode, dev)
107
Mauro Carvalho Chehabfe3c5652015-12-13 08:40:45 -0200108/**
109 * media_devnode_register - register a media device node
110 *
Mauro Carvalho Chehab0db5c792016-06-16 08:04:40 -0300111 * @mdev: struct media_device we want to register a device node
Mauro Carvalho Chehab163f1e92016-03-23 11:22:57 -0300112 * @devnode: media device node structure we want to register
Mauro Carvalho Chehabfe3c5652015-12-13 08:40:45 -0200113 * @owner: should be filled with %THIS_MODULE
114 *
115 * The registration code assigns minor numbers and registers the new device node
116 * with the kernel. An error is returned if no free minor number can be found,
117 * or if the registration of the device node fails.
118 *
119 * Zero is returned on success.
120 *
121 * Note that if the media_devnode_register call fails, the release() callback of
122 * the media_devnode structure is *not* called, so the caller is responsible for
123 * freeing any data.
124 */
Mauro Carvalho Chehaba087ce72016-04-27 19:28:26 -0300125int __must_check media_devnode_register(struct media_device *mdev,
126 struct media_devnode *devnode,
Sakari Ailus85de7212013-12-12 12:38:17 -0300127 struct module *owner);
Mauro Carvalho Chehabfe3c5652015-12-13 08:40:45 -0200128
129/**
Shuah Khan6f0dd242016-06-10 14:37:23 -0300130 * media_devnode_unregister_prepare - clear the media device node register bit
131 * @devnode: the device node to prepare for unregister
132 *
133 * This clears the passed device register bit. Future open calls will be met
134 * with errors. Should be called before media_devnode_unregister() to avoid
135 * races with unregister and device file open calls.
136 *
137 * This function can safely be called if the device node has never been
138 * registered or has already been unregistered.
139 */
140void media_devnode_unregister_prepare(struct media_devnode *devnode);
141
142/**
Mauro Carvalho Chehabfe3c5652015-12-13 08:40:45 -0200143 * media_devnode_unregister - unregister a media device node
Mauro Carvalho Chehab163f1e92016-03-23 11:22:57 -0300144 * @devnode: the device node to unregister
Mauro Carvalho Chehabfe3c5652015-12-13 08:40:45 -0200145 *
146 * This unregisters the passed device. Future open calls will be met with
147 * errors.
148 *
Shuah Khan6f0dd242016-06-10 14:37:23 -0300149 * Should be called after media_devnode_unregister_prepare()
Mauro Carvalho Chehabfe3c5652015-12-13 08:40:45 -0200150 */
Mauro Carvalho Chehab163f1e92016-03-23 11:22:57 -0300151void media_devnode_unregister(struct media_devnode *devnode);
Laurent Pinchartcf4b9212009-12-09 08:39:56 -0300152
Mauro Carvalho Chehab75c7e292015-12-13 09:00:00 -0200153/**
154 * media_devnode_data - returns a pointer to the &media_devnode
155 *
156 * @filp: pointer to struct &file
157 */
Laurent Pinchartcf4b9212009-12-09 08:39:56 -0300158static inline struct media_devnode *media_devnode_data(struct file *filp)
159{
160 return filp->private_data;
161}
162
Mauro Carvalho Chehab75c7e292015-12-13 09:00:00 -0200163/**
164 * media_devnode_is_registered - returns true if &media_devnode is registered;
165 * false otherwise.
166 *
Mauro Carvalho Chehab163f1e92016-03-23 11:22:57 -0300167 * @devnode: pointer to struct &media_devnode.
Mauro Carvalho Chehaba087ce72016-04-27 19:28:26 -0300168 *
169 * Note: If mdev is NULL, it also returns false.
Mauro Carvalho Chehab75c7e292015-12-13 09:00:00 -0200170 */
Mauro Carvalho Chehab163f1e92016-03-23 11:22:57 -0300171static inline int media_devnode_is_registered(struct media_devnode *devnode)
Laurent Pinchartcf4b9212009-12-09 08:39:56 -0300172{
Mauro Carvalho Chehaba087ce72016-04-27 19:28:26 -0300173 if (!devnode)
174 return false;
175
Mauro Carvalho Chehab163f1e92016-03-23 11:22:57 -0300176 return test_bit(MEDIA_FLAG_REGISTERED, &devnode->flags);
Laurent Pinchartcf4b9212009-12-09 08:39:56 -0300177}
178
179#endif /* _MEDIA_DEVNODE_H */