xref: /openbmc/linux/drivers/usb/serial/bus.c (revision b34081f1)
1 /*
2  * USB Serial Converter Bus specific functions
3  *
4  * Copyright (C) 2002 Greg Kroah-Hartman (greg@kroah.com)
5  *
6  *	This program is free software; you can redistribute it and/or
7  *	modify it under the terms of the GNU General Public License version
8  *	2 as published by the Free Software Foundation.
9  */
10 
11 #include <linux/kernel.h>
12 #include <linux/errno.h>
13 #include <linux/tty.h>
14 #include <linux/slab.h>
15 #include <linux/module.h>
16 #include <linux/usb.h>
17 #include <linux/usb/serial.h>
18 
19 static int usb_serial_device_match(struct device *dev,
20 						struct device_driver *drv)
21 {
22 	struct usb_serial_driver *driver;
23 	const struct usb_serial_port *port;
24 
25 	/*
26 	 * drivers are already assigned to ports in serial_probe so it's
27 	 * a simple check here.
28 	 */
29 	port = to_usb_serial_port(dev);
30 	if (!port)
31 		return 0;
32 
33 	driver = to_usb_serial_driver(drv);
34 
35 	if (driver == port->serial->type)
36 		return 1;
37 
38 	return 0;
39 }
40 
41 static ssize_t port_number_show(struct device *dev,
42 				struct device_attribute *attr, char *buf)
43 {
44 	struct usb_serial_port *port = to_usb_serial_port(dev);
45 
46 	return sprintf(buf, "%d\n", port->port_number);
47 }
48 static DEVICE_ATTR_RO(port_number);
49 
50 static int usb_serial_device_probe(struct device *dev)
51 {
52 	struct usb_serial_driver *driver;
53 	struct usb_serial_port *port;
54 	int retval = 0;
55 	int minor;
56 
57 	port = to_usb_serial_port(dev);
58 	if (!port) {
59 		retval = -ENODEV;
60 		goto exit;
61 	}
62 
63 	/* make sure suspend/resume doesn't race against port_probe */
64 	retval = usb_autopm_get_interface(port->serial->interface);
65 	if (retval)
66 		goto exit;
67 
68 	driver = port->serial->type;
69 	if (driver->port_probe) {
70 		retval = driver->port_probe(port);
71 		if (retval)
72 			goto exit_with_autopm;
73 	}
74 
75 	retval = device_create_file(dev, &dev_attr_port_number);
76 	if (retval) {
77 		if (driver->port_remove)
78 			retval = driver->port_remove(port);
79 		goto exit_with_autopm;
80 	}
81 
82 	minor = port->minor;
83 	tty_register_device(usb_serial_tty_driver, minor, dev);
84 	dev_info(&port->serial->dev->dev,
85 		 "%s converter now attached to ttyUSB%d\n",
86 		 driver->description, minor);
87 
88 exit_with_autopm:
89 	usb_autopm_put_interface(port->serial->interface);
90 exit:
91 	return retval;
92 }
93 
94 static int usb_serial_device_remove(struct device *dev)
95 {
96 	struct usb_serial_driver *driver;
97 	struct usb_serial_port *port;
98 	int retval = 0;
99 	int minor;
100 
101 	port = to_usb_serial_port(dev);
102 	if (!port)
103 		return -ENODEV;
104 
105 	/* make sure suspend/resume doesn't race against port_remove */
106 	usb_autopm_get_interface(port->serial->interface);
107 
108 	minor = port->minor;
109 	tty_unregister_device(usb_serial_tty_driver, minor);
110 
111 	device_remove_file(&port->dev, &dev_attr_port_number);
112 
113 	driver = port->serial->type;
114 	if (driver->port_remove)
115 		retval = driver->port_remove(port);
116 
117 	dev_info(dev, "%s converter now disconnected from ttyUSB%d\n",
118 		 driver->description, minor);
119 
120 	usb_autopm_put_interface(port->serial->interface);
121 	return retval;
122 }
123 
124 static ssize_t new_id_store(struct device_driver *driver,
125 			    const char *buf, size_t count)
126 {
127 	struct usb_serial_driver *usb_drv = to_usb_serial_driver(driver);
128 	ssize_t retval = usb_store_new_id(&usb_drv->dynids, driver, buf, count);
129 
130 	if (retval >= 0 && usb_drv->usb_driver != NULL)
131 		retval = usb_store_new_id(&usb_drv->usb_driver->dynids,
132 					  &usb_drv->usb_driver->drvwrap.driver,
133 					  buf, count);
134 	return retval;
135 }
136 
137 static ssize_t new_id_show(struct device_driver *driver, char *buf)
138 {
139 	struct usb_serial_driver *usb_drv = to_usb_serial_driver(driver);
140 
141 	return usb_show_dynids(&usb_drv->dynids, buf);
142 }
143 static DRIVER_ATTR_RW(new_id);
144 
145 static struct attribute *usb_serial_drv_attrs[] = {
146 	&driver_attr_new_id.attr,
147 	NULL,
148 };
149 ATTRIBUTE_GROUPS(usb_serial_drv);
150 
151 static void free_dynids(struct usb_serial_driver *drv)
152 {
153 	struct usb_dynid *dynid, *n;
154 
155 	spin_lock(&drv->dynids.lock);
156 	list_for_each_entry_safe(dynid, n, &drv->dynids.list, node) {
157 		list_del(&dynid->node);
158 		kfree(dynid);
159 	}
160 	spin_unlock(&drv->dynids.lock);
161 }
162 
163 struct bus_type usb_serial_bus_type = {
164 	.name =		"usb-serial",
165 	.match =	usb_serial_device_match,
166 	.probe =	usb_serial_device_probe,
167 	.remove =	usb_serial_device_remove,
168 	.drv_groups = 	usb_serial_drv_groups,
169 };
170 
171 int usb_serial_bus_register(struct usb_serial_driver *driver)
172 {
173 	int retval;
174 
175 	driver->driver.bus = &usb_serial_bus_type;
176 	spin_lock_init(&driver->dynids.lock);
177 	INIT_LIST_HEAD(&driver->dynids.list);
178 
179 	retval = driver_register(&driver->driver);
180 
181 	return retval;
182 }
183 
184 void usb_serial_bus_deregister(struct usb_serial_driver *driver)
185 {
186 	free_dynids(driver);
187 	driver_unregister(&driver->driver);
188 }
189 
190