include/media/media-devnode.h

   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
  87 static inline struct media_devnode *media_devnode_data(struct file *filp)
  88 {
  89         return filp->private_data;
  90 }
  91
  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 */