/*
* v4l2-fh.h
*
* V4L2 file handle. Store per file handle data for the V4L2
* framework. Using file handles is optional for the drivers.
*
* Copyright (C) 2009--2010 Nokia Corporation.
*
* Contact: Sakari Ailus <[email protected]>
*
* 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., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA
*/

#ifndef V4L2_FH_H
#define V4L2_FH_H

#include <linux/fs.h>
#include <linux/list.h>
#include <linux/videodev2.h>

struct video_device;
struct v4l2_ctrl_handler;

struct v4l2_fh {
struct list_head list;
struct video_device *vdev;
struct v4l2_ctrl_handler *ctrl_handler;
enum v4l2_priority prio;

/* Events */
wait_queue_head_t wait;
struct list_head subscribed; /* Subscribed events */
struct list_head available; /* Dequeueable event */
unsigned int navailable;
u32 sequence;
};

/*
* Initialise the file handle. Parts of the V4L2 framework using the
* file handles should be initialised in this function. Must be called
* from driver's v4l2_file_operations->open() handler if the driver
* uses v4l2_fh.
*/
void v4l2_fh_init(struct v4l2_fh *fh, struct video_device *vdev);
/*
* Add the fh to the list of file handles on a video_device. The file
* handle must be initialised first.
*/
void v4l2_fh_add(struct v4l2_fh *fh);
/*
* Can be used as the open() op of v4l2_file_operations.
* It allocates a v4l2_fh and inits and adds it to the video_device associated
* with the file pointer.
*/
int v4l2_fh_open(struct file *filp);
/*
* Remove file handle from the list of file handles. Must be called in
* v4l2_file_operations->release() handler if the driver uses v4l2_fh.
* On error filp->private_data will be NULL, otherwise it will point to
* the v4l2_fh struct.
*/
void v4l2_fh_del(struct v4l2_fh *fh);
/*
* Release resources related to a file handle. Parts of the V4L2
* framework using the v4l2_fh must release their resources here, too.
* Must be called in v4l2_file_operations->release() handler if the
* driver uses v4l2_fh.
*/
void v4l2_fh_exit(struct v4l2_fh *fh);
/*
* Can be used as the release() op of v4l2_file_operations.
* It deletes and exits the v4l2_fh associated with the file pointer and
* frees it. It will do nothing if filp->private_data (the pointer to the
* v4l2_fh struct) is NULL. This function always returns 0.
*/
int v4l2_fh_release(struct file *filp);
/*
* Returns 1 if this filehandle is the only filehandle opened for the
* associated video_device. If fh is NULL, then it returns 0.
*/
int v4l2_fh_is_singular(struct v4l2_fh *fh);
/*
* Helper function with struct file as argument. If filp->private_data is
* NULL, then it will return 0.
*/
static inline int v4l2_fh_is_singular_file(struct file *filp)
{
return v4l2_fh_is_singular(filp->private_data);
}

#endif /* V4L2_EVENT_H */