xref: /openbmc/linux/drivers/usb/serial/bus.c (revision 7b6d864b)
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 show_port_number(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 
49 static DEVICE_ATTR(port_number, S_IRUGO, show_port_number, NULL);
50 
51 static int usb_serial_device_probe(struct device *dev)
52 {
53 	struct usb_serial_driver *driver;
54 	struct usb_serial_port *port;
55 	int retval = 0;
56 	int minor;
57 
58 	port = to_usb_serial_port(dev);
59 	if (!port) {
60 		retval = -ENODEV;
61 		goto exit;
62 	}
63 
64 	/* make sure suspend/resume doesn't race against port_probe */
65 	retval = usb_autopm_get_interface(port->serial->interface);
66 	if (retval)
67 		goto exit;
68 
69 	driver = port->serial->type;
70 	if (driver->port_probe) {
71 		retval = driver->port_probe(port);
72 		if (retval)
73 			goto exit_with_autopm;
74 	}
75 
76 	retval = device_create_file(dev, &dev_attr_port_number);
77 	if (retval) {
78 		if (driver->port_remove)
79 			retval = driver->port_remove(port);
80 		goto exit_with_autopm;
81 	}
82 
83 	minor = port->minor;
84 	tty_register_device(usb_serial_tty_driver, minor, dev);
85 	dev_info(&port->serial->dev->dev,
86 		 "%s converter now attached to ttyUSB%d\n",
87 		 driver->description, minor);
88 
89 exit_with_autopm:
90 	usb_autopm_put_interface(port->serial->interface);
91 exit:
92 	return retval;
93 }
94 
95 static int usb_serial_device_remove(struct device *dev)
96 {
97 	struct usb_serial_driver *driver;
98 	struct usb_serial_port *port;
99 	int retval = 0;
100 	int minor;
101 
102 	port = to_usb_serial_port(dev);
103 	if (!port)
104 		return -ENODEV;
105 
106 	/* make sure suspend/resume doesn't race against port_remove */
107 	usb_autopm_get_interface(port->serial->interface);
108 
109 	minor = port->minor;
110 	tty_unregister_device(usb_serial_tty_driver, minor);
111 
112 	device_remove_file(&port->dev, &dev_attr_port_number);
113 
114 	driver = port->serial->type;
115 	if (driver->port_remove)
116 		retval = driver->port_remove(port);
117 
118 	dev_info(dev, "%s converter now disconnected from ttyUSB%d\n",
119 		 driver->description, minor);
120 
121 	usb_autopm_put_interface(port->serial->interface);
122 	return retval;
123 }
124 
125 static ssize_t store_new_id(struct device_driver *driver,
126 			    const char *buf, size_t count)
127 {
128 	struct usb_serial_driver *usb_drv = to_usb_serial_driver(driver);
129 	ssize_t retval = usb_store_new_id(&usb_drv->dynids, driver, buf, count);
130 
131 	if (retval >= 0 && usb_drv->usb_driver != NULL)
132 		retval = usb_store_new_id(&usb_drv->usb_driver->dynids,
133 					  &usb_drv->usb_driver->drvwrap.driver,
134 					  buf, count);
135 	return retval;
136 }
137 
138 static ssize_t show_dynids(struct device_driver *driver, char *buf)
139 {
140 	struct usb_serial_driver *usb_drv = to_usb_serial_driver(driver);
141 
142 	return usb_show_dynids(&usb_drv->dynids, buf);
143 }
144 
145 static struct driver_attribute drv_attrs[] = {
146 	__ATTR(new_id, S_IRUGO | S_IWUSR, show_dynids, store_new_id),
147 	__ATTR_NULL,
148 };
149 
150 static void free_dynids(struct usb_serial_driver *drv)
151 {
152 	struct usb_dynid *dynid, *n;
153 
154 	spin_lock(&drv->dynids.lock);
155 	list_for_each_entry_safe(dynid, n, &drv->dynids.list, node) {
156 		list_del(&dynid->node);
157 		kfree(dynid);
158 	}
159 	spin_unlock(&drv->dynids.lock);
160 }
161 
162 struct bus_type usb_serial_bus_type = {
163 	.name =		"usb-serial",
164 	.match =	usb_serial_device_match,
165 	.probe =	usb_serial_device_probe,
166 	.remove =	usb_serial_device_remove,
167 	.drv_attrs = 	drv_attrs,
168 };
169 
170 int usb_serial_bus_register(struct usb_serial_driver *driver)
171 {
172 	int retval;
173 
174 	driver->driver.bus = &usb_serial_bus_type;
175 	spin_lock_init(&driver->dynids.lock);
176 	INIT_LIST_HEAD(&driver->dynids.list);
177 
178 	retval = driver_register(&driver->driver);
179 
180 	return retval;
181 }
182 
183 void usb_serial_bus_deregister(struct usb_serial_driver *driver)
184 {
185 	free_dynids(driver);
186 	driver_unregister(&driver->driver);
187 }
188 
189