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Sakari Ailus1babcb42010-03-23 09:25:26 -03001/*
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 *
9 * Contact: Sakari Ailus <sakari.ailus@maxwell.research.nokia.com>
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
29#include <linux/list.h>
30
31struct video_device;
Sakari Ailusc3b5b022010-03-01 05:14:18 -030032struct v4l2_events;
Sakari Ailus1babcb42010-03-23 09:25:26 -030033
34struct v4l2_fh {
35 struct list_head list;
36 struct video_device *vdev;
Sakari Ailusc3b5b022010-03-01 05:14:18 -030037 struct v4l2_events *events; /* events, pending and subscribed */
Hans Verkuilfc5602b2010-12-29 13:36:50 -030038 enum v4l2_priority prio;
Sakari Ailus1babcb42010-03-23 09:25:26 -030039};
40
41/*
42 * Initialise the file handle. Parts of the V4L2 framework using the
43 * file handles should be initialised in this function. Must be called
44 * from driver's v4l2_file_operations->open() handler if the driver
45 * uses v4l2_fh.
46 */
47int v4l2_fh_init(struct v4l2_fh *fh, struct video_device *vdev);
48/*
49 * Add the fh to the list of file handles on a video_device. The file
50 * handle must be initialised first.
51 */
52void v4l2_fh_add(struct v4l2_fh *fh);
53/*
Hans Verkuil73cb4202011-01-08 09:36:04 -030054 * Can be used as the open() op of v4l2_file_operations.
55 * It allocates a v4l2_fh and inits and adds it to the video_device associated
56 * with the file pointer.
57 */
58int v4l2_fh_open(struct file *filp);
59/*
Sakari Ailus1babcb42010-03-23 09:25:26 -030060 * Remove file handle from the list of file handles. Must be called in
61 * v4l2_file_operations->release() handler if the driver uses v4l2_fh.
Hans Verkuil73cb4202011-01-08 09:36:04 -030062 * On error filp->private_data will be NULL, otherwise it will point to
63 * the v4l2_fh struct.
Sakari Ailus1babcb42010-03-23 09:25:26 -030064 */
65void v4l2_fh_del(struct v4l2_fh *fh);
66/*
67 * Release resources related to a file handle. Parts of the V4L2
68 * framework using the v4l2_fh must release their resources here, too.
69 * Must be called in v4l2_file_operations->release() handler if the
70 * driver uses v4l2_fh.
71 */
72void v4l2_fh_exit(struct v4l2_fh *fh);
Hans Verkuil73cb4202011-01-08 09:36:04 -030073/*
74 * Can be used as the release() op of v4l2_file_operations.
75 * It deletes and exits the v4l2_fh associated with the file pointer and
76 * frees it. It will do nothing if filp->private_data (the pointer to the
77 * v4l2_fh struct) is NULL. This function always returns 0.
78 */
79int v4l2_fh_release(struct file *filp);
Hans Verkuildfddb242011-01-08 09:38:02 -030080/*
81 * Returns 1 if this filehandle is the only filehandle opened for the
82 * associated video_device. If fh is NULL, then it returns 0.
83 */
84int v4l2_fh_is_singular(struct v4l2_fh *fh);
85/*
86 * Helper function with struct file as argument. If filp->private_data is
87 * NULL, then it will return 0.
88 */
89static inline int v4l2_fh_is_singular_file(struct file *filp)
90{
91 return v4l2_fh_is_singular(filp->private_data);
92}
Sakari Ailus1babcb42010-03-23 09:25:26 -030093
94#endif /* V4L2_EVENT_H */