/* 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 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 */