4 * V4L2 file handle. Store per file handle data for the V4L2
5 * framework. Using file handles is optional for the drivers.
7 * Copyright (C) 2009--2010 Nokia Corporation.
9 * Contact: Sakari Ailus <sakari.ailus@iki.fi>
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.
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.
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
30 #include <linux/list.h>
31 #include <linux/videodev2.h>
34 struct v4l2_ctrl_handler;
37 struct list_head list;
38 struct video_device *vdev;
39 struct v4l2_ctrl_handler *ctrl_handler;
40 enum v4l2_priority prio;
43 wait_queue_head_t wait;
44 struct list_head subscribed; /* Subscribed events */
45 struct list_head available; /* Dequeueable event */
46 struct mutex subscribe_lock;
47 unsigned int navailable;
50 #if IS_ENABLED(CONFIG_V4L2_MEM2MEM_DEV)
51 struct v4l2_m2m_ctx *m2m_ctx;
56 * Initialise the file handle. Parts of the V4L2 framework using the
57 * file handles should be initialised in this function. Must be called
58 * from driver's v4l2_file_operations->open() handler if the driver
61 void v4l2_fh_init(struct v4l2_fh *fh, struct video_device *vdev);
63 * Add the fh to the list of file handles on a video_device. The file
64 * handle must be initialised first.
66 void v4l2_fh_add(struct v4l2_fh *fh);
68 * Can be used as the open() op of v4l2_file_operations.
69 * It allocates a v4l2_fh and inits and adds it to the video_device associated
70 * with the file pointer.
72 int v4l2_fh_open(struct file *filp);
74 * Remove file handle from the list of file handles. Must be called in
75 * v4l2_file_operations->release() handler if the driver uses v4l2_fh.
76 * On error filp->private_data will be NULL, otherwise it will point to
79 void v4l2_fh_del(struct v4l2_fh *fh);
81 * Release resources related to a file handle. Parts of the V4L2
82 * framework using the v4l2_fh must release their resources here, too.
83 * Must be called in v4l2_file_operations->release() handler if the
84 * driver uses v4l2_fh.
86 void v4l2_fh_exit(struct v4l2_fh *fh);
88 * Can be used as the release() op of v4l2_file_operations.
89 * It deletes and exits the v4l2_fh associated with the file pointer and
90 * frees it. It will do nothing if filp->private_data (the pointer to the
91 * v4l2_fh struct) is NULL. This function always returns 0.
93 int v4l2_fh_release(struct file *filp);
95 * Returns 1 if this filehandle is the only filehandle opened for the
96 * associated video_device. If fh is NULL, then it returns 0.
98 int v4l2_fh_is_singular(struct v4l2_fh *fh);
100 * Helper function with struct file as argument. If filp->private_data is
101 * NULL, then it will return 0.
103 static inline int v4l2_fh_is_singular_file(struct file *filp)
105 return v4l2_fh_is_singular(filp->private_data);
108 #endif /* V4L2_EVENT_H */