[mirror_ubuntu-bionic-kernel.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.
 */

#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 - Describes a V4L2 file handler
 *
 * @list: list of file handlers
 * @vdev: pointer to &struct video_device
 * @ctrl_handler: pointer to &struct v4l2_ctrl_handler
 * @prio: priority of the file handler, as defined by &enum v4l2_priority
 *
 * @wait: event' s wait queue
 * @subscribed: list of subscribed events
 * @available: list of events waiting to be dequeued
 * @navailable: number of available events at @available list
 * @sequence: event sequence number
 * @m2m_ctx: pointer to &struct v4l2_m2m_ctx
 */
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;
	struct list_head	available;
	unsigned int		navailable;
	u32			sequence;

#if IS_ENABLED(CONFIG_V4L2_MEM2MEM_DEV)
	struct v4l2_m2m_ctx	*m2m_ctx;
#endif
};

/**
 * v4l2_fh_init - Initialise the file handle.
 *
 * @fh: pointer to &struct v4l2_fh
 * @vdev: pointer to &struct video_device
 *
 * 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 &struct v4l2_fh.
 */
void v4l2_fh_init(struct v4l2_fh *fh, struct video_device *vdev);

/**
 * v4l2_fh_add - Add the fh to the list of file handles on a video_device.
 *
 * @fh: pointer to &struct v4l2_fh
 *
 * .. note::
 *    The @fh file handle must be initialised first.
 */
void v4l2_fh_add(struct v4l2_fh *fh);

/**
 * v4l2_fh_open - Ancillary routine that can be used as the open\(\) op
 *	of v4l2_file_operations.
 *
 * @filp: pointer to struct file
 *
 * It allocates a v4l2_fh and inits and adds it to the &struct video_device
 * associated with the file pointer.
 */
int v4l2_fh_open(struct file *filp);

/**
 * v4l2_fh_del - Remove file handle from the list of file handles.
 *
 * @fh: pointer to &struct v4l2_fh
 *
 * On error filp->private_data will be %NULL, otherwise it will point to
 * the &struct v4l2_fh.
 *
 * .. note::
 *    Must be called in v4l2_file_operations->release\(\) handler if the driver
 *    uses &struct v4l2_fh.
 */
void v4l2_fh_del(struct v4l2_fh *fh);

/**
 * v4l2_fh_exit - Release resources related to a file handle.
 *
 * @fh: pointer to &struct v4l2_fh
 *
 * Parts of the V4L2 framework using the v4l2_fh must release their
 * resources here, too.
 *
 * .. note::
 *    Must be called in v4l2_file_operations->release\(\) handler if the
 *    driver uses &struct v4l2_fh.
 */
void v4l2_fh_exit(struct v4l2_fh *fh);

/**
 * v4l2_fh_release - Ancillary routine that can be used as the release\(\) op
 *	of v4l2_file_operations.
 *
 * @filp: pointer to struct file
 *
 * 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);

/**
 * v4l2_fh_is_singular - Returns 1 if this filehandle is the only filehandle
 *	 opened for the associated video_device.
 *
 * @fh: pointer to &struct v4l2_fh
 *
 * If @fh is NULL, then it returns 0.
 */
int v4l2_fh_is_singular(struct v4l2_fh *fh);

/**
 * v4l2_fh_is_singular_file - Returns 1 if this filehandle is the only
 *	filehandle opened for the associated video_device.
 *
 * @filp: pointer to struct file
 *
 * This is a helper function variant of v4l2_fh_is_singular() with uses
 * 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.
1babcb46 SA	19	*/
	20
	21	#ifndef V4L2_FH_H
	22	#define V4L2_FH_H
	23
4f1af2a3	24	#include <linux/fs.h>
1babcb46	25	#include <linux/list.h>
c8d185ce	26	#include <linux/videodev2.h>
1babcb46 SA	27
1babcb46 SA	28	struct video_device;
2d28b686	29	struct v4l2_ctrl_handler;
1babcb46	30
4ada120e MCC	31	/**
	32	* struct v4l2_fh - Describes a V4L2 file handler
	33	*
	34	* @list: list of file handlers
	35	* @vdev: pointer to &struct video_device
	36	* @ctrl_handler: pointer to &struct v4l2_ctrl_handler
	37	* @prio: priority of the file handler, as defined by &enum v4l2_priority
	38	*
	39	* @wait: event' s wait queue
	40	* @subscribed: list of subscribed events
	41	* @available: list of events waiting to be dequeued
	42	* @navailable: number of available events at @available list
	43	* @sequence: event sequence number
	44	* @m2m_ctx: pointer to &struct v4l2_m2m_ctx
	45	*/
1babcb46 SA	46	struct v4l2_fh {
	47	struct list_head list;
	48	struct video_device *vdev;
2d28b686	49	struct v4l2_ctrl_handler *ctrl_handler;
fc5602be	50	enum v4l2_priority prio;
523f46d6 HV	51
	52	/* Events */
	53	wait_queue_head_t wait;
4ada120e MCC	54	struct list_head subscribed;
4ada120e MCC	55	struct list_head available;
523f46d6	56	unsigned int navailable;
523f46d6	57	u32 sequence;
8e6e8f93 SN	58
	59	#if IS_ENABLED(CONFIG_V4L2_MEM2MEM_DEV)
	60	struct v4l2_m2m_ctx *m2m_ctx;
	61	#endif
1babcb46 SA	62	};
1babcb46 SA	63
4ada120e MCC	64	/**
	65	* v4l2_fh_init - Initialise the file handle.
	66	*
	67	* @fh: pointer to &struct v4l2_fh
	68	* @vdev: pointer to &struct video_device
	69	*
	70	* Parts of the V4L2 framework using the
1babcb46	71	* file handles should be initialised in this function. Must be called
4ada120e MCC	72	* from driver's v4l2_file_operations->open\(\) handler if the driver
4ada120e MCC	73	* uses &struct v4l2_fh.
1babcb46	74	*/
523f46d6	75	void v4l2_fh_init(struct v4l2_fh fh, struct video_device vdev);
4ada120e MCC	76
	77	/**
	78	* v4l2_fh_add - Add the fh to the list of file handles on a video_device.
	79	*
	80	* @fh: pointer to &struct v4l2_fh
	81	*
	82	* .. note::
	83	* The @fh file handle must be initialised first.
1babcb46 SA	84	*/
1babcb46 SA	85	void v4l2_fh_add(struct v4l2_fh *fh);
4ada120e MCC	86
	87	/**
	88	* v4l2_fh_open - Ancillary routine that can be used as the open\(\) op
	89	* of v4l2_file_operations.
	90	*
	91	* @filp: pointer to struct file
	92	*
	93	* It allocates a v4l2_fh and inits and adds it to the &struct video_device
	94	* associated with the file pointer.
73cb4206 HV	95	*/
73cb4206 HV	96	int v4l2_fh_open(struct file *filp);
4ada120e MCC	97
	98	/**
	99	* v4l2_fh_del - Remove file handle from the list of file handles.
	100	*
	101	* @fh: pointer to &struct v4l2_fh
	102	*
	103	* On error filp->private_data will be %NULL, otherwise it will point to
	104	* the &struct v4l2_fh.
	105	*
	106	* .. note::
	107	* Must be called in v4l2_file_operations->release\(\) handler if the driver
	108	* uses &struct v4l2_fh.
1babcb46 SA	109	*/
1babcb46 SA	110	void v4l2_fh_del(struct v4l2_fh *fh);
4ada120e MCC	111
	112	/**
	113	* v4l2_fh_exit - Release resources related to a file handle.
	114	*
	115	* @fh: pointer to &struct v4l2_fh
	116	*
	117	* Parts of the V4L2 framework using the v4l2_fh must release their
	118	* resources here, too.
	119	*
	120	* .. note::
	121	* Must be called in v4l2_file_operations->release\(\) handler if the
	122	* driver uses &struct v4l2_fh.
1babcb46 SA	123	*/
1babcb46 SA	124	void v4l2_fh_exit(struct v4l2_fh *fh);
4ada120e MCC	125
	126	/**
	127	* v4l2_fh_release - Ancillary routine that can be used as the release\(\) op
	128	* of v4l2_file_operations.
	129	*
	130	* @filp: pointer to struct file
	131	*
73cb4206 HV	132	* It deletes and exits the v4l2_fh associated with the file pointer and
73cb4206 HV	133	* frees it. It will do nothing if filp->private_data (the pointer to the
4ada120e MCC	134	* v4l2_fh struct) is %NULL.
	135	*
	136	* This function always returns 0.
73cb4206 HV	137	*/
73cb4206 HV	138	int v4l2_fh_release(struct file *filp);
4ada120e MCC	139
	140	/**
	141	* v4l2_fh_is_singular - Returns 1 if this filehandle is the only filehandle
	142	* opened for the associated video_device.
	143	*
	144	* @fh: pointer to &struct v4l2_fh
	145	*
	146	* If @fh is NULL, then it returns 0.
dfddb244 HV	147	*/
dfddb244 HV	148	int v4l2_fh_is_singular(struct v4l2_fh *fh);
4ada120e MCC	149
	150	/**
	151	* v4l2_fh_is_singular_file - Returns 1 if this filehandle is the only
	152	* filehandle opened for the associated video_device.
	153	*
	154	* @filp: pointer to struct file
	155	*
	156	* This is a helper function variant of v4l2_fh_is_singular() with uses
	157	* struct file as argument.
	158	*
	159	* If filp->private_data is %NULL, then it will return 0.
dfddb244 HV	160	*/
	161	static inline int v4l2_fh_is_singular_file(struct file *filp)
	162	{
	163	return v4l2_fh_is_singular(filp->private_data);
	164	}
1babcb46 SA	165
1babcb46 SA	166	#endif /* V4L2_EVENT_H */