[deliverable/linux.git] / include / media / v4l2-fh.h

/*
 * 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 <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., 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 */
Commit	Line	Data
1babcb46 SA	1	/*
	2	* v4l2-fh.h
	3	*
	4	* V4L2 file handle. Store per file handle data for the V4L2
	5	* framework. Using file handles is optional for the drivers.
	6	*
	7	* Copyright (C) 2009--2010 Nokia Corporation.
	8	*
8c5dff90	9	* Contact: Sakari Ailus <sakari.ailus@iki.fi>
1babcb46 SA	10	*
	11	* This program is free software; you can redistribute it and/or
	12	* modify it under the terms of the GNU General Public License
	13	* version 2 as published by the Free Software Foundation.
	14	*
	15	* This program is distributed in the hope that it will be useful, but
	16	* WITHOUT ANY WARRANTY; without even the implied warranty of
	17	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	18	* General Public License for more details.
	19	*
	20	* You should have received a copy of the GNU General Public License
	21	* along with this program; if not, write to the Free Software
	22	* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
	23	* 02110-1301 USA
	24	*/
	25
	26	#ifndef V4L2_FH_H
	27	#define V4L2_FH_H
	28
4f1af2a3	29	#include <linux/fs.h>
1babcb46	30	#include <linux/list.h>
c8d185ce	31	#include <linux/videodev2.h>
1babcb46 SA	32
1babcb46 SA	33	struct video_device;
2d28b686	34	struct v4l2_ctrl_handler;
1babcb46 SA	35
	36	struct v4l2_fh {
	37	struct list_head list;
	38	struct video_device *vdev;
2d28b686	39	struct v4l2_ctrl_handler *ctrl_handler;
fc5602be	40	enum v4l2_priority prio;
523f46d6 HV	41
	42	/* Events */
	43	wait_queue_head_t wait;
	44	struct list_head subscribed; /* Subscribed events */
523f46d6 HV	45	struct list_head available; /* Dequeueable event */
523f46d6 HV	46	unsigned int navailable;
523f46d6	47	u32 sequence;
1babcb46 SA	48	};
	49
	50	/*
	51	* Initialise the file handle. Parts of the V4L2 framework using the
	52	* file handles should be initialised in this function. Must be called
	53	* from driver's v4l2_file_operations->open() handler if the driver
	54	* uses v4l2_fh.
	55	*/
523f46d6	56	void v4l2_fh_init(struct v4l2_fh fh, struct video_device vdev);
1babcb46 SA	57	/*
	58	* Add the fh to the list of file handles on a video_device. The file
	59	* handle must be initialised first.
	60	*/
	61	void v4l2_fh_add(struct v4l2_fh *fh);
73cb4206 HV	62	/*
	63	* Can be used as the open() op of v4l2_file_operations.
	64	* It allocates a v4l2_fh and inits and adds it to the video_device associated
	65	* with the file pointer.
	66	*/
	67	int v4l2_fh_open(struct file *filp);
1babcb46 SA	68	/*
	69	* Remove file handle from the list of file handles. Must be called in
	70	* v4l2_file_operations->release() handler if the driver uses v4l2_fh.
73cb4206 HV	71	* On error filp->private_data will be NULL, otherwise it will point to
73cb4206 HV	72	* the v4l2_fh struct.
1babcb46 SA	73	*/
	74	void v4l2_fh_del(struct v4l2_fh *fh);
	75	/*
	76	* Release resources related to a file handle. Parts of the V4L2
	77	* framework using the v4l2_fh must release their resources here, too.
	78	* Must be called in v4l2_file_operations->release() handler if the
	79	* driver uses v4l2_fh.
	80	*/
	81	void v4l2_fh_exit(struct v4l2_fh *fh);
73cb4206 HV	82	/*
	83	* Can be used as the release() op of v4l2_file_operations.
	84	* It deletes and exits the v4l2_fh associated with the file pointer and
	85	* frees it. It will do nothing if filp->private_data (the pointer to the
	86	* v4l2_fh struct) is NULL. This function always returns 0.
	87	*/
	88	int v4l2_fh_release(struct file *filp);
dfddb244 HV	89	/*
	90	* Returns 1 if this filehandle is the only filehandle opened for the
	91	* associated video_device. If fh is NULL, then it returns 0.
	92	*/
	93	int v4l2_fh_is_singular(struct v4l2_fh *fh);
	94	/*
	95	* Helper function with struct file as argument. If filp->private_data is
	96	* NULL, then it will return 0.
	97	*/
	98	static inline int v4l2_fh_is_singular_file(struct file *filp)
	99	{
	100	return v4l2_fh_is_singular(filp->private_data);
	101	}
1babcb46 SA	102
1babcb46 SA	103	#endif /* V4L2_EVENT_H */