177 lines
5.7 KiB
C
177 lines
5.7 KiB
C
/*
|
|
* 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.
|
|
*
|
|
* --
|
|
*
|
|
* 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>
|
|
|
|
struct media_device;
|
|
|
|
/*
|
|
* 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 - Media device file operations
|
|
*
|
|
* @owner: should be filled with %THIS_MODULE
|
|
* @read: pointer to the function that implements read() syscall
|
|
* @write: pointer to the function that implements write() syscall
|
|
* @poll: pointer to the function that implements poll() syscall
|
|
* @ioctl: pointer to the function that implements ioctl() syscall
|
|
* @compat_ioctl: pointer to the function that will handle 32 bits userspace
|
|
* calls to the the ioctl() syscall on a Kernel compiled with 64 bits.
|
|
* @open: pointer to the function that implements open() syscall
|
|
* @release: pointer to the function that will release the resources allocated
|
|
* by the @open function.
|
|
*/
|
|
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 *);
|
|
__poll_t (*poll) (struct file *, struct poll_table_struct *);
|
|
long (*ioctl) (struct file *, unsigned int, unsigned long);
|
|
long (*compat_ioctl) (struct file *, unsigned int, unsigned long);
|
|
int (*open) (struct file *);
|
|
int (*release) (struct file *);
|
|
};
|
|
|
|
/**
|
|
* struct media_devnode - Media device node
|
|
* @media_dev: pointer to struct &media_device
|
|
* @fops: pointer to struct &media_file_operations with media device ops
|
|
* @dev: pointer to struct &device containing the media controller device
|
|
* @cdev: struct cdev pointer character device
|
|
* @parent: parent device
|
|
* @minor: device node minor number
|
|
* @flags: flags, combination of the ``MEDIA_FLAG_*`` constants
|
|
* @release: release callback called at the end of ``media_devnode_release()``
|
|
* routine at media-device.c.
|
|
*
|
|
* 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 {
|
|
struct media_device *media_dev;
|
|
|
|
/* 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 *devnode);
|
|
};
|
|
|
|
/* dev to media_devnode */
|
|
#define to_media_devnode(cd) container_of(cd, struct media_devnode, dev)
|
|
|
|
/**
|
|
* media_devnode_register - register a media device node
|
|
*
|
|
* @mdev: struct media_device we want to register a device node
|
|
* @devnode: media device node structure we want to register
|
|
* @owner: should be filled with %THIS_MODULE
|
|
*
|
|
* The registration code assigns minor numbers and registers the new device node
|
|
* with the kernel. An error is returned if no free minor number can be found,
|
|
* or if the registration of the device node fails.
|
|
*
|
|
* Zero is returned on success.
|
|
*
|
|
* Note that if the media_devnode_register call fails, the release() callback of
|
|
* the media_devnode structure is *not* called, so the caller is responsible for
|
|
* freeing any data.
|
|
*/
|
|
int __must_check media_devnode_register(struct media_device *mdev,
|
|
struct media_devnode *devnode,
|
|
struct module *owner);
|
|
|
|
/**
|
|
* media_devnode_unregister_prepare - clear the media device node register bit
|
|
* @devnode: the device node to prepare for unregister
|
|
*
|
|
* This clears the passed device register bit. Future open calls will be met
|
|
* with errors. Should be called before media_devnode_unregister() to avoid
|
|
* races with unregister and device file open calls.
|
|
*
|
|
* This function can safely be called if the device node has never been
|
|
* registered or has already been unregistered.
|
|
*/
|
|
void media_devnode_unregister_prepare(struct media_devnode *devnode);
|
|
|
|
/**
|
|
* media_devnode_unregister - unregister a media device node
|
|
* @devnode: the device node to unregister
|
|
*
|
|
* This unregisters the passed device. Future open calls will be met with
|
|
* errors.
|
|
*
|
|
* Should be called after media_devnode_unregister_prepare()
|
|
*/
|
|
void media_devnode_unregister(struct media_devnode *devnode);
|
|
|
|
/**
|
|
* media_devnode_data - returns a pointer to the &media_devnode
|
|
*
|
|
* @filp: pointer to struct &file
|
|
*/
|
|
static inline struct media_devnode *media_devnode_data(struct file *filp)
|
|
{
|
|
return filp->private_data;
|
|
}
|
|
|
|
/**
|
|
* media_devnode_is_registered - returns true if &media_devnode is registered;
|
|
* false otherwise.
|
|
*
|
|
* @devnode: pointer to struct &media_devnode.
|
|
*
|
|
* Note: If mdev is NULL, it also returns false.
|
|
*/
|
|
static inline int media_devnode_is_registered(struct media_devnode *devnode)
|
|
{
|
|
if (!devnode)
|
|
return false;
|
|
|
|
return test_bit(MEDIA_FLAG_REGISTERED, &devnode->flags);
|
|
}
|
|
|
|
#endif /* _MEDIA_DEVNODE_H */
|