linux/drivers/usb/core/file.c

// SPDX-License-Identifier: GPL-2.0
/*
 * drivers/usb/core/file.c
 *
 * (C) Copyright Linus Torvalds 1999
 * (C) Copyright Johannes Erdfelt 1999-2001
 * (C) Copyright Andreas Gal 1999
 * (C) Copyright Gregory P. Smith 1999
 * (C) Copyright Deti Fliegl 1999 (new USB architecture)
 * (C) Copyright Randy Dunlap 2000
 * (C) Copyright David Brownell 2000-2001 (kernel hotplug, usb_device_id,
 *	more docs, etc)
 * (C) Copyright Yggdrasil Computing, Inc. 2000
 *     (usb_device_id matching changes by Adam J. Richter)
 * (C) Copyright Greg Kroah-Hartman 2002-2003
 *
 * Released under the GPLv2 only.
 */

#include <linux/module.h>
#include <linux/errno.h>
#include <linux/rwsem.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/usb.h>

#include "usb.h"

#define MAX_USB_MINORS …
static const struct file_operations *usb_minors[MAX_USB_MINORS];
static DECLARE_RWSEM(minor_rwsem);

static int usb_open(struct inode *inode, struct file *file)
{ … }

static const struct file_operations usb_fops = …;

static char *usb_devnode(const struct device *dev, umode_t *mode)
{ … }

const struct class usbmisc_class = …;

int usb_major_init(void)
{ … }

void usb_major_cleanup(void)
{ … }

/**
 * usb_register_dev - register a USB device, and ask for a minor number
 * @intf: pointer to the usb_interface that is being registered
 * @class_driver: pointer to the usb_class_driver for this device
 *
 * This should be called by all USB drivers that use the USB major number.
 * If CONFIG_USB_DYNAMIC_MINORS is enabled, the minor number will be
 * dynamically allocated out of the list of available ones.  If it is not
 * enabled, the minor number will be based on the next available free minor,
 * starting at the class_driver->minor_base.
 *
 * This function also creates a usb class device in the sysfs tree.
 *
 * usb_deregister_dev() must be called when the driver is done with
 * the minor numbers given out by this function.
 *
 * Return: -EINVAL if something bad happens with trying to register a
 * device, and 0 on success.
 */
int usb_register_dev(struct usb_interface *intf,
		     struct usb_class_driver *class_driver)
{ … }
EXPORT_SYMBOL_GPL(…);

/**
 * usb_deregister_dev - deregister a USB device's dynamic minor.
 * @intf: pointer to the usb_interface that is being deregistered
 * @class_driver: pointer to the usb_class_driver for this device
 *
 * Used in conjunction with usb_register_dev().  This function is called
 * when the USB driver is finished with the minor numbers gotten from a
 * call to usb_register_dev() (usually when the device is disconnected
 * from the system.)
 *
 * This function also removes the usb class device from the sysfs tree.
 *
 * This should be called by all drivers that use the USB major number.
 */
void usb_deregister_dev(struct usb_interface *intf,
			struct usb_class_driver *class_driver)
{ … }
EXPORT_SYMBOL_GPL(…);