JFIF$        dd7 

Viewing File: /usr/src/kernels/5.14.0-570.32.1.el9_6.x86_64/include/media/media-devnode.h

/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * Media device node
 *
 * Copyright (C) 2010 Nokia Corporation
 *
 * Contacts: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
 *	     Sakari Ailus <sakari.ailus@iki.fi>
 *
 * --
 *
 * Common functions for media-related drivers to register and unregister media
 * device nodes.
 */

#ifndef _MEDIA_DEVNODE_H
#define _MEDIA_DEVNODE_H

#include <linux/poll.h>
#include <linux/fs.h>
#include <linux/device.h>
#include <linux/cdev.h>

struct media_device;

/*
 * Flag to mark the media_devnode struct as registered. Drivers must not touch
 * this flag directly, it will be set and cleared by media_devnode_register and
 * media_devnode_unregister.
 */
#define MEDIA_FLAG_REGISTERED	0

/**
 * struct media_file_operations - Media device file operations
 *
 * @owner: should be filled with %THIS_MODULE
 * @read: pointer to the function that implements read() syscall
 * @write: pointer to the function that implements write() syscall
 * @poll: pointer to the function that implements poll() syscall
 * @ioctl: pointer to the function that implements ioctl() syscall
 * @compat_ioctl: pointer to the function that will handle 32 bits userspace
 *	calls to the ioctl() syscall on a Kernel compiled with 64 bits.
 * @open: pointer to the function that implements open() syscall
 * @release: pointer to the function that will release the resources allocated
 *	by the @open function.
 */
struct media_file_operations {
	struct module *owner;
	ssize_t (*read) (struct file *, char __user *, size_t, loff_t *);
	ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *);
	__poll_t (*poll) (struct file *, struct poll_table_struct *);
	long (*ioctl) (struct file *, unsigned int, unsigned long);
	long (*compat_ioctl) (struct file *, unsigned int, unsigned long);
	int (*open) (struct file *);
	int (*release) (struct file *);
};

/**
 * struct media_devnode - Media device node
 * @media_dev:	pointer to struct &media_device
 * @fops:	pointer to struct &media_file_operations with media device ops
 * @dev:	pointer to struct &device containing the media controller device
 * @cdev:	struct cdev pointer character device
 * @parent:	parent device
 * @minor:	device node minor number
 * @flags:	flags, combination of the ``MEDIA_FLAG_*`` constants
 * @release:	release callback called at the end of ``media_devnode_release()``
 *		routine at media-device.c.
 *
 * This structure represents a media-related device node.
 *
 * The @parent is a physical device. It must be set by core or device drivers
 * before registering the node.
 */
struct media_devnode {
	struct media_device *media_dev;

	/* device ops */
	const struct media_file_operations *fops;

	/* sysfs */
	struct device dev;		/* media device */
	struct cdev cdev;		/* character device */
	struct device *parent;		/* device parent */

	/* device info */
	int minor;
	unsigned long flags;		/* Use bitops to access flags */

	/* callbacks */
	void (*release)(struct media_devnode *devnode);
};

/* dev to media_devnode */
#define to_media_devnode(cd) container_of(cd, struct media_devnode, dev)

/**
 * media_devnode_register - register a media device node
 *
 * @mdev: struct media_device we want to register a device node
 * @devnode: media device node structure we want to register
 * @owner: should be filled with %THIS_MODULE
 *
 * The registration code assigns minor numbers and registers the new device node
 * with the kernel. An error is returned if no free minor number can be found,
 * or if the registration of the device node fails.
 *
 * Zero is returned on success.
 *
 * Note that if the media_devnode_register call fails, the release() callback of
 * the media_devnode structure is *not* called, so the caller is responsible for
 * freeing any data.
 */
int __must_check media_devnode_register(struct media_device *mdev,
					struct media_devnode *devnode,
					struct module *owner);

/**
 * media_devnode_unregister_prepare - clear the media device node register bit
 * @devnode: the device node to prepare for unregister
 *
 * This clears the passed device register bit. Future open calls will be met
 * with errors. Should be called before media_devnode_unregister() to avoid
 * races with unregister and device file open calls.
 *
 * This function can safely be called if the device node has never been
 * registered or has already been unregistered.
 */
void media_devnode_unregister_prepare(struct media_devnode *devnode);

/**
 * media_devnode_unregister - unregister a media device node
 * @devnode: the device node to unregister
 *
 * This unregisters the passed device. Future open calls will be met with
 * errors.
 *
 * Should be called after media_devnode_unregister_prepare()
 */
void media_devnode_unregister(struct media_devnode *devnode);

/**
 * media_devnode_data - returns a pointer to the &media_devnode
 *
 * @filp: pointer to struct &file
 */
static inline struct media_devnode *media_devnode_data(struct file *filp)
{
	return filp->private_data;
}

/**
 * media_devnode_is_registered - returns true if &media_devnode is registered;
 *	false otherwise.
 *
 * @devnode: pointer to struct &media_devnode.
 *
 * Note: If mdev is NULL, it also returns false.
 */
static inline int media_devnode_is_registered(struct media_devnode *devnode)
{
	if (!devnode)
		return false;

	return test_bit(MEDIA_FLAG_REGISTERED, &devnode->flags);
}

#endif /* _MEDIA_DEVNODE_H */
Back to Directory  nL+D550H?Mx ,D"v]qv;6*Zqn)ZP0!1 A "#a$2Qr D8 a Ri[f\mIykIw0cuFcRı?lO7к_f˓[C$殷WF<_W ԣsKcëIzyQy/_LKℂ;C",pFA:/]=H  ~,ls/9ć:[=/#f;)x{ٛEQ )~ =𘙲r*2~ a _V=' kumFD}KYYC)({ *g&f`툪ry`=^cJ.I](*`wq1dđ#̩͑0;H]u搂@:~וKL Nsh}OIR*8:2 !lDJVo(3=M(zȰ+i*NAr6KnSl)!JJӁ* %݉?|D}d5:eP0R;{$X'xF@.ÊB {,WJuQɲRI;9QE琯62fT.DUJ;*cP A\ILNj!J۱+O\͔]ޒS߼Jȧc%ANolՎprULZԛerE2=XDXgVQeӓk yP7U*omQIs,K`)6\G3t?pgjrmۛجwluGtfh9uyP0D;Uڽ"OXlif$)&|ML0Zrm1[HXPlPR0'G=i2N+0e2]]9VTPO׮7h(F*癈'=QVZDF,d߬~TX G[`le69CR(!S2!P <0x<!1AQ "Raq02Br#SCTb ?Ζ"]mH5WR7k.ۛ!}Q~+yԏz|@T20S~Kek *zFf^2X*(@8r?CIuI|֓>^ExLgNUY+{.RѪ τV׸YTD I62'8Y27'\TP.6d&˦@Vqi|8-OΕ]ʔ U=TL8=;6c| !qfF3aů&~$l}'NWUs$Uk^SV:U# 6w++s&r+nڐ{@29 gL u"TÙM=6(^"7r}=6YݾlCuhquympǦ GjhsǜNlɻ}o7#S6aw4!OSrD57%|?x>L |/nD6?/8w#[)L7+6〼T ATg!%5MmZ/c-{1_Je"|^$'O&ޱմTrb$w)R$& N1EtdU3Uȉ1pM"N*(DNyd96.(jQ)X 5cQɎMyW?Q*!R>6=7)Xj5`J]e8%t!+'!1Q5 !1 AQaqё#2"0BRb?Gt^## .llQT $v,,m㵜5ubV =sY+@d{N! dnO<.-B;_wJt6;QJd.Qc%p{ 1,sNDdFHI0ГoXшe黅XۢF:)[FGXƹ/w_cMeD,ʡcc.WDtA$j@:) -# u c1<@ۗ9F)KJ-hpP]_x[qBlbpʖw q"LFGdƶ*s+ډ_Zc"?%t[IP 6J]#=ɺVvvCGsGh1 >)6|ey?Lӣm,4GWUi`]uJVoVDG< SB6ϏQ@ TiUlyOU0kfV~~}SZ@*WUUi##; s/[=!7}"WN]'(L! ~y5g9T̅JkbM' +s:S +B)v@Mj e Cf jE 0Y\QnzG1д~Wo{T9?`Rmyhsy3!HAD]mc1~2LSu7xT;j$`}4->L#vzŏILS ֭T{rjGKC;bpU=-`BsK.SFw4Mq]ZdHS0)tLg