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include/media/media-devnode.h 2.87 KB
cf4b9211b   Laurent Pinchart   [media] media: Me...
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  /*
   * Media device node
   *
   * Copyright (C) 2010 Nokia Corporation
   *
   * Contacts: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
   *	     Sakari Ailus <sakari.ailus@iki.fi>
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   *
   * --
   *
   * Common functions for media-related drivers to register and unregister media
   * device nodes.
   */
  
  #ifndef _MEDIA_DEVNODE_H
  #define _MEDIA_DEVNODE_H
  
  #include <linux/poll.h>
  #include <linux/fs.h>
  #include <linux/device.h>
  #include <linux/cdev.h>
  
  /*
   * Flag to mark the media_devnode struct as registered. Drivers must not touch
   * this flag directly, it will be set and cleared by media_devnode_register and
   * media_devnode_unregister.
   */
  #define MEDIA_FLAG_REGISTERED	0
  
  struct media_file_operations {
  	struct module *owner;
  	ssize_t (*read) (struct file *, char __user *, size_t, loff_t *);
  	ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *);
  	unsigned int (*poll) (struct file *, struct poll_table_struct *);
  	long (*ioctl) (struct file *, unsigned int, unsigned long);
  	int (*open) (struct file *);
  	int (*release) (struct file *);
  };
  
  /**
   * struct media_devnode - Media device node
   * @parent:	parent device
   * @minor:	device node minor number
   * @flags:	flags, combination of the MEDIA_FLAG_* constants
   *
   * This structure represents a media-related device node.
   *
   * The @parent is a physical device. It must be set by core or device drivers
   * before registering the node.
   */
  struct media_devnode {
  	/* device ops */
  	const struct media_file_operations *fops;
  
  	/* sysfs */
  	struct device dev;		/* media device */
  	struct cdev cdev;		/* character device */
  	struct device *parent;		/* device parent */
  
  	/* device info */
  	int minor;
  	unsigned long flags;		/* Use bitops to access flags */
  
  	/* callbacks */
  	void (*release)(struct media_devnode *mdev);
  };
  
  /* dev to media_devnode */
  #define to_media_devnode(cd) container_of(cd, struct media_devnode, dev)
  
  int __must_check media_devnode_register(struct media_devnode *mdev);
  void media_devnode_unregister(struct media_devnode *mdev);
  
  static inline struct media_devnode *media_devnode_data(struct file *filp)
  {
  	return filp->private_data;
  }
  
  static inline int media_devnode_is_registered(struct media_devnode *mdev)
  {
  	return test_bit(MEDIA_FLAG_REGISTERED, &mdev->flags);
  }
  
  #endif /* _MEDIA_DEVNODE_H */