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161 lines
4.2 KiB
161 lines
4.2 KiB
/* SPDX-License-Identifier: GPL-2.0-only */ |
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/* |
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* v4l2-fh.h |
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* |
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* V4L2 file handle. Store per file handle data for the V4L2 |
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* framework. Using file handles is optional for the drivers. |
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* |
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* Copyright (C) 2009--2010 Nokia Corporation. |
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* |
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* Contact: Sakari Ailus <[email protected]> |
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*/ |
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#ifndef V4L2_FH_H |
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#define V4L2_FH_H |
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#include <linux/fs.h> |
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#include <linux/kconfig.h> |
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#include <linux/list.h> |
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#include <linux/videodev2.h> |
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struct video_device; |
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struct v4l2_ctrl_handler; |
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/** |
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* struct v4l2_fh - Describes a V4L2 file handler |
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* |
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* @list: list of file handlers |
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* @vdev: pointer to &struct video_device |
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* @ctrl_handler: pointer to &struct v4l2_ctrl_handler |
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* @prio: priority of the file handler, as defined by &enum v4l2_priority |
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* |
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* @wait: event' s wait queue |
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* @subscribe_lock: serialise changes to the subscribed list; guarantee that |
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* the add and del event callbacks are orderly called |
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* @subscribed: list of subscribed events |
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* @available: list of events waiting to be dequeued |
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* @navailable: number of available events at @available list |
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* @sequence: event sequence number |
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* |
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* @m2m_ctx: pointer to &struct v4l2_m2m_ctx |
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*/ |
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struct v4l2_fh { |
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struct list_head list; |
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struct video_device *vdev; |
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struct v4l2_ctrl_handler *ctrl_handler; |
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enum v4l2_priority prio; |
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/* Events */ |
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wait_queue_head_t wait; |
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struct mutex subscribe_lock; |
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struct list_head subscribed; |
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struct list_head available; |
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unsigned int navailable; |
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u32 sequence; |
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struct v4l2_m2m_ctx *m2m_ctx; |
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}; |
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/** |
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* v4l2_fh_init - Initialise the file handle. |
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* |
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* @fh: pointer to &struct v4l2_fh |
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* @vdev: pointer to &struct video_device |
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* |
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* Parts of the V4L2 framework using the |
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* file handles should be initialised in this function. Must be called |
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* from driver's v4l2_file_operations->open\(\) handler if the driver |
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* uses &struct v4l2_fh. |
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*/ |
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void v4l2_fh_init(struct v4l2_fh *fh, struct video_device *vdev); |
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/** |
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* v4l2_fh_add - Add the fh to the list of file handles on a video_device. |
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* |
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* @fh: pointer to &struct v4l2_fh |
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* |
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* .. note:: |
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* The @fh file handle must be initialised first. |
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*/ |
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void v4l2_fh_add(struct v4l2_fh *fh); |
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/** |
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* v4l2_fh_open - Ancillary routine that can be used as the open\(\) op |
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* of v4l2_file_operations. |
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* |
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* @filp: pointer to struct file |
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* |
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* It allocates a v4l2_fh and inits and adds it to the &struct video_device |
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* associated with the file pointer. |
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*/ |
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int v4l2_fh_open(struct file *filp); |
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/** |
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* v4l2_fh_del - Remove file handle from the list of file handles. |
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* |
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* @fh: pointer to &struct v4l2_fh |
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* |
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* On error filp->private_data will be %NULL, otherwise it will point to |
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* the &struct v4l2_fh. |
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* |
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* .. note:: |
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* Must be called in v4l2_file_operations->release\(\) handler if the driver |
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* uses &struct v4l2_fh. |
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*/ |
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void v4l2_fh_del(struct v4l2_fh *fh); |
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/** |
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* v4l2_fh_exit - Release resources related to a file handle. |
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* |
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* @fh: pointer to &struct v4l2_fh |
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* |
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* Parts of the V4L2 framework using the v4l2_fh must release their |
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* resources here, too. |
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* |
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* .. note:: |
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* Must be called in v4l2_file_operations->release\(\) handler if the |
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* driver uses &struct v4l2_fh. |
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*/ |
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void v4l2_fh_exit(struct v4l2_fh *fh); |
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/** |
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* v4l2_fh_release - Ancillary routine that can be used as the release\(\) op |
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* of v4l2_file_operations. |
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* |
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* @filp: pointer to struct file |
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* |
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* It deletes and exits the v4l2_fh associated with the file pointer and |
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* frees it. It will do nothing if filp->private_data (the pointer to the |
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* v4l2_fh struct) is %NULL. |
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* |
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* This function always returns 0. |
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*/ |
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int v4l2_fh_release(struct file *filp); |
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/** |
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* v4l2_fh_is_singular - Returns 1 if this filehandle is the only filehandle |
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* opened for the associated video_device. |
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* |
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* @fh: pointer to &struct v4l2_fh |
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* |
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* If @fh is NULL, then it returns 0. |
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*/ |
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int v4l2_fh_is_singular(struct v4l2_fh *fh); |
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/** |
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* v4l2_fh_is_singular_file - Returns 1 if this filehandle is the only |
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* filehandle opened for the associated video_device. |
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* |
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* @filp: pointer to struct file |
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* |
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* This is a helper function variant of v4l2_fh_is_singular() with uses |
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* struct file as argument. |
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* |
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* If filp->private_data is %NULL, then it will return 0. |
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*/ |
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static inline int v4l2_fh_is_singular_file(struct file *filp) |
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{ |
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return v4l2_fh_is_singular(filp->private_data); |
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} |
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#endif /* V4L2_EVENT_H */
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