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"
36 	int err = -ENODEV;  in usb_open()
46 	/* Curiouser and curiouser... NULL ->open() as "no device" ? */  in usb_open()
47 	if (file->f_op->open)  in usb_open()
48 		err = file->f_op->open(inode, file);  in usb_open()
70 	if (!drv || !drv->devnode)  in usb_devnode()
72 	return drv->devnode(dev, mode);  in usb_devnode()
80 		kref_get(&usb_class->kref);  in init_usb_class()
86 		result = -ENOMEM;  in init_usb_class()
90 	kref_init(&usb_class->kref);  in init_usb_class()
91 	usb_class->class = class_create(THIS_MODULE, "usbmisc");  in init_usb_class()
92 	if (IS_ERR(usb_class->class)) {  in init_usb_class()
93 		result = PTR_ERR(usb_class->class);  in init_usb_class()
94 		printk(KERN_ERR "class_create failed for usb devices\n");  in init_usb_class()
99 	usb_class->class->devnode = usb_devnode;  in init_usb_class()
108 	class_destroy(usb_class->class);  in release_usb_class()
116 	kref_put(&usb_class->kref, release_usb_class);  in destroy_usb_class()
124 	error = register_chrdev(USB_MAJOR, "usb", &usb_fops);  in usb_major_init()
126 		printk(KERN_ERR "Unable to get major %d for usb devices\n",  in usb_major_init()
134 	unregister_chrdev(USB_MAJOR, "usb");  in usb_major_cleanup()
138  * usb_register_dev - register a USB device, and ask for a minor number
142  * This should be called by all USB drivers that use the USB major number.
146  * starting at the class_driver->minor_base.
148  * This function also creates a usb class device in the sysfs tree.
153  * Return: -EINVAL if something bad happens with trying to register a
160 	int minor_base = class_driver->minor_base;  in usb_register_dev()
173 	if (class_driver->fops == NULL)  in usb_register_dev()
174 		return -EINVAL;  in usb_register_dev()
175 	if (intf->minor >= 0)  in usb_register_dev()
176 		return -EADDRINUSE;  in usb_register_dev()
185 	dev_dbg(&intf->dev, "looking for a minor, starting at %d\n", minor_base);  in usb_register_dev()
192 		usb_minors[minor] = class_driver->fops;  in usb_register_dev()
193 		intf->minor = minor;  in usb_register_dev()
196 	if (intf->minor < 0) {  in usb_register_dev()
198 		return -EXFULL;  in usb_register_dev()
201 	/* create a usb class device for this usb interface */  in usb_register_dev()
202 	snprintf(name, sizeof(name), class_driver->name, minor - minor_base);  in usb_register_dev()
203 	intf->usb_dev = device_create(usb_class->class, &intf->dev,  in usb_register_dev()
206 	if (IS_ERR(intf->usb_dev)) {  in usb_register_dev()
208 		intf->minor = -1;  in usb_register_dev()
209 		retval = PTR_ERR(intf->usb_dev);  in usb_register_dev()
217  * usb_deregister_dev - deregister a USB device's dynamic minor.
222  * when the USB driver is finished with the minor numbers gotten from a
226  * This function also removes the usb class device from the sysfs tree.
228  * This should be called by all drivers that use the USB major number.
233 	if (intf->minor == -1)  in usb_deregister_dev()
236 	dev_dbg(&intf->dev, "removing %d minor\n", intf->minor);  in usb_deregister_dev()
237 	device_destroy(usb_class->class, MKDEV(USB_MAJOR, intf->minor));  in usb_deregister_dev()
240 	usb_minors[intf->minor] = NULL;  in usb_deregister_dev()
243 	intf->usb_dev = NULL;  in usb_deregister_dev()
244 	intf->minor = -1;  in usb_deregister_dev()