1 // SPDX-License-Identifier: GPL-2.0
3  * drivers/usb/core/file.c
5  * (C) Copyright Linus Torvalds 1999
6  * (C) Copyright Johannes Erdfelt 1999-2001
7  * (C) Copyright Andreas Gal 1999
8  * (C) Copyright Gregory P. Smith 1999
9  * (C) Copyright Deti Fliegl 1999 (new USB architecture)
10  * (C) Copyright Randy Dunlap 2000
11  * (C) Copyright David Brownell 2000-2001 (kernel hotplug, usb_device_id,
13  * (C) Copyright Yggdrasil Computing, Inc. 2000
15  * (C) Copyright Greg Kroah-Hartman 2002-2003
25 #include <linux/usb.h>
27 #include "usb.h"
35 	int err = -ENODEV;  in usb_open()
45 	/* Curiouser and curiouser... NULL ->open() as "no device" ? */  in usb_open()
46 	if (file->f_op->open)  in usb_open()
47 		err = file->f_op->open(inode, file);  in usb_open()
64 	if (!drv || !drv->devnode)  in usb_devnode()
66 	return drv->devnode(dev, mode);  in usb_devnode()
78 	error = register_chrdev(USB_MAJOR, "usb", &usb_fops);  in usb_major_init()
80 		printk(KERN_ERR "Unable to get major %d for usb devices\n",  in usb_major_init()
88 	unregister_chrdev(USB_MAJOR, "usb");  in usb_major_cleanup()
92  * usb_register_dev - register a USB device, and ask for a minor number
96  * This should be called by all USB drivers that use the USB major number.
100  * starting at the class_driver->minor_base.
102  * This function also creates a usb class device in the sysfs tree.
107  * Return: -EINVAL if something bad happens with trying to register a
114 	int minor_base = class_driver->minor_base;  in usb_register_dev()
127 	if (class_driver->fops == NULL)  in usb_register_dev()
128 		return -EINVAL;  in usb_register_dev()
129 	if (intf->minor >= 0)  in usb_register_dev()
130 		return -EADDRINUSE;  in usb_register_dev()
132 	dev_dbg(&intf->dev, "looking for a minor, starting at %d\n", minor_base);  in usb_register_dev()
139 		usb_minors[minor] = class_driver->fops;  in usb_register_dev()
140 		intf->minor = minor;  in usb_register_dev()
143 	if (intf->minor < 0) {  in usb_register_dev()
145 		return -EXFULL;  in usb_register_dev()
148 	/* create a usb class device for this usb interface */  in usb_register_dev()
149 	snprintf(name, sizeof(name), class_driver->name, minor - minor_base);  in usb_register_dev()
150 	intf->usb_dev = device_create(&usbmisc_class, &intf->dev,  in usb_register_dev()
153 	if (IS_ERR(intf->usb_dev)) {  in usb_register_dev()
155 		intf->minor = -1;  in usb_register_dev()
156 		retval = PTR_ERR(intf->usb_dev);  in usb_register_dev()
164  * usb_deregister_dev - deregister a USB device's dynamic minor.
169  * when the USB driver is finished with the minor numbers gotten from a
173  * This function also removes the usb class device from the sysfs tree.
175  * This should be called by all drivers that use the USB major number.
180 	if (intf->minor == -1)  in usb_deregister_dev()
183 	dev_dbg(&intf->dev, "removing %d minor\n", intf->minor);  in usb_deregister_dev()
184 	device_destroy(&usbmisc_class, MKDEV(USB_MAJOR, intf->minor));  in usb_deregister_dev()
187 	usb_minors[intf->minor] = NULL;  in usb_deregister_dev()
190 	intf->usb_dev = NULL;  in usb_deregister_dev()
191 	intf->minor = -1;  in usb_deregister_dev()