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awilliam
GitHub Repository: awilliam/linux-vfio
 Path: blob/master/include/media/media-devnode.h
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/*

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 * Media device node

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 *

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 * Copyright (C) 2010 Nokia Corporation

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 *

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 * Contacts: Laurent Pinchart <[email protected]>

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 *	     Sakari Ailus <[email protected]>

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 *

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 * This program is free software; you can redistribute it and/or modify

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 * it under the terms of the GNU General Public License version 2 as

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 * published by the Free Software Foundation.

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 *

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 * This program is distributed in the hope that it will be useful,

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 * but WITHOUT ANY WARRANTY; without even the implied warranty of

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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

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 * GNU General Public License for more details.

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 *

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 * You should have received a copy of the GNU General Public License

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 * along with this program; if not, write to the Free Software

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 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

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 *

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 * --

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 *

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 * Common functions for media-related drivers to register and unregister media

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 * device nodes.

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 */

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#ifndef _MEDIA_DEVNODE_H

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#define _MEDIA_DEVNODE_H

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#include <linux/poll.h>

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#include <linux/fs.h>

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#include <linux/device.h>

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#include <linux/cdev.h>

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/*

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 * Flag to mark the media_devnode struct as registered. Drivers must not touch

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 * this flag directly, it will be set and cleared by media_devnode_register and

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 * media_devnode_unregister.

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 */

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#define MEDIA_FLAG_REGISTERED	0

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struct media_file_operations {

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	struct module *owner;

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	ssize_t (*read) (struct file *, char __user *, size_t, loff_t *);

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	ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *);

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	unsigned int (*poll) (struct file *, struct poll_table_struct *);

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	long (*ioctl) (struct file *, unsigned int, unsigned long);

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	int (*open) (struct file *);

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	int (*release) (struct file *);

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};

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/**

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 * struct media_devnode - Media device node

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 * @parent:	parent device

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 * @minor:	device node minor number

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 * @flags:	flags, combination of the MEDIA_FLAG_* constants

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 *

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 * This structure represents a media-related device node.

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 *

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 * The @parent is a physical device. It must be set by core or device drivers

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 * before registering the node.

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 */

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struct media_devnode {

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	/* device ops */

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	const struct media_file_operations *fops;

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	/* sysfs */

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	struct device dev;		/* media device */

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	struct cdev cdev;		/* character device */

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	struct device *parent;		/* device parent */

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	/* device info */

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	int minor;

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	unsigned long flags;		/* Use bitops to access flags */

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	/* callbacks */

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	void (*release)(struct media_devnode *mdev);

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};

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/* dev to media_devnode */

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#define to_media_devnode(cd) container_of(cd, struct media_devnode, dev)

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int __must_check media_devnode_register(struct media_devnode *mdev);

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void media_devnode_unregister(struct media_devnode *mdev);

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static inline struct media_devnode *media_devnode_data(struct file *filp)

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{

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	return filp->private_data;

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}

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static inline int media_devnode_is_registered(struct media_devnode *mdev)

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{

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	return test_bit(MEDIA_FLAG_REGISTERED, &mdev->flags);

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}

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#endif /* _MEDIA_DEVNODE_H */

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