linux/include/media/media-devnode.h
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   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
  43struct 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 */
  64struct 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
  84int __must_check media_devnode_register(struct media_devnode *mdev);
  85void media_devnode_unregister(struct media_devnode *mdev);
  86
  87static inline struct media_devnode *media_devnode_data(struct file *filp)
  88{
  89        return filp->private_data;
  90}
  91
  92static 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
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