1 // SPDX-License-Identifier: GPL-2.0
14  * Made things a lot mode modular - easy to compile in just one or two
17  * Support for loadable modules. 8-Sep-95 Philip Blundell <[email protected]>
20  *		Alan Cox <[email protected]> 21-Jan-96
22  * Dynamic minors and /proc/mice by Alessandro Rubini. 26-Mar-96
24  * Renamed to misc and miscdevice to be more accurate. Alan Cox 26-Mar-96
34  * Added devfs support. Richard Gooch <[email protected]>  10-Jan-1998
61  * Assigned numbers, used for dynamic minors
63 #define DYNAMIC_MINORS 128 /* like dynamic majors */
72 		ret = ida_alloc_max(&misc_minors_ida, DYNAMIC_MINORS - 1, GFP_KERNEL);  in misc_minor_alloc()
74 			ret = DYNAMIC_MINORS - ret - 1;  in misc_minor_alloc()
80 		/* specific minor, check if it is in dynamic or misc dynamic range  */  in misc_minor_alloc()
82 			minor = DYNAMIC_MINORS - minor - 1;  in misc_minor_alloc()
87 			/* case of non-dynamic minors, no need to allocate id */  in misc_minor_alloc()
97 		ida_free(&misc_minors_ida, DYNAMIC_MINORS - minor - 1);  in misc_minor_free()
123 	seq_printf(seq, "%3i %s\n", p->minor, p->name ? p->name : "");  in misc_seq_show()
140 	int err = -ENODEV;  in misc_open()
146 		if (iter->minor != minor)  in misc_open()
149 		new_fops = fops_get(iter->fops);  in misc_open()
155 		request_module("char-major-%d-%d", MISC_MAJOR, minor);  in misc_open()
159 			if (iter->minor != minor)  in misc_open()
162 			new_fops = fops_get(iter->fops);  in misc_open()
172 	 * file operations, including f_op->open below  in misc_open()
174 	file->private_data = c;  in misc_open()
178 	if (file->f_op->open)  in misc_open()
179 		err = file->f_op->open(inode, file);  in misc_open()
185 static char *misc_devnode(const struct device *dev, umode_t *mode)  in misc_devnode()  argument
189 	if (mode && c->mode)  in misc_devnode()
190 		*mode = c->mode;  in misc_devnode()
191 	if (c->nodename)  in misc_devnode()
192 		return kstrdup(c->nodename, GFP_KERNEL);  in misc_devnode()
208  *	misc_register	-	register a miscellaneous device
218  *	syscall to the device sets file->private_data to point to the
229 	bool is_dynamic = (misc->minor == MISC_DYNAMIC_MINOR);  in misc_register()
231 	INIT_LIST_HEAD(&misc->list);  in misc_register()
236 		int i = misc_minor_alloc(misc->minor);  in misc_register()
239 			err = -EBUSY;  in misc_register()
242 		misc->minor = i;  in misc_register()
248 			if (c->minor == misc->minor) {  in misc_register()
249 				err = -EBUSY;  in misc_register()
254 		i = misc_minor_alloc(misc->minor);  in misc_register()
256 			err = -EBUSY;  in misc_register()
261 	dev = MKDEV(MISC_MAJOR, misc->minor);  in misc_register()
263 	misc->this_device =  in misc_register()
264 		device_create_with_groups(&misc_class, misc->parent, dev,  in misc_register()
265 					  misc, misc->groups, "%s", misc->name);  in misc_register()
266 	if (IS_ERR(misc->this_device)) {  in misc_register()
267 		misc_minor_free(misc->minor);  in misc_register()
269 			misc->minor = MISC_DYNAMIC_MINOR;  in misc_register()
271 		err = PTR_ERR(misc->this_device);  in misc_register()
279 	list_add(&misc->list, &misc_list);  in misc_register()
287  *	misc_deregister - unregister a miscellaneous device
296 	if (WARN_ON(list_empty(&misc->list)))  in misc_deregister()
300 	list_del(&misc->list);  in misc_deregister()
301 	device_destroy(&misc_class, MKDEV(MISC_MAJOR, misc->minor));  in misc_deregister()
302 	misc_minor_free(misc->minor);  in misc_deregister()
317 	err = -EIO;  in misc_init()