Edit File: 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/list.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 mutex subscribe_lock; 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 */