drivers/usb/serial/bus.c

   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->number - port->serial->minor);
  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         struct device *tty_dev;
  56         int retval = 0;
  57         int minor;
  58
  59         port = to_usb_serial_port(dev);
  60         if (!port) {
  61                 retval = -ENODEV;
  62                 goto exit;
  63         }
  64         if (port->dev_state != PORT_REGISTERING)
  65                 goto exit;
  66
  67         driver = port->serial->type;
  68         if (driver->port_probe) {
  69                 retval = driver->port_probe(port);
  70                 if (retval)
  71                         goto exit;
  72         }
  73
  74         retval = device_create_file(dev, &dev_attr_port_number);
  75         if (retval) {
  76                 if (driver->port_remove)
  77                         driver->port_remove(port);
  78                 goto exit;
  79         }
  80
  81         minor = port->number;
  82         tty_dev = tty_register_device(usb_serial_tty_driver, minor, dev);
  83         if (IS_ERR(tty_dev)) {
  84                 retval = PTR_ERR(tty_dev);
  85                 device_remove_file(dev, &dev_attr_port_number);
  86                 if (driver->port_remove)
  87                         driver->port_remove(port);
  88                 goto exit;
  89         }
  90
  91         dev_info(&port->serial->dev->dev,
  92                  "%s converter now attached to ttyUSB%d\n",
  93                  driver->description, minor);
  94
  95 exit:
  96         return retval;
  97 }
  98
  99 static int usb_serial_device_remove(struct device *dev)
 100 {
 101         struct usb_serial_driver *driver;
 102         struct usb_serial_port *port;
 103         int retval = 0;
 104         int minor;
 105
 106         port = to_usb_serial_port(dev);
 107         if (!port)
 108                 return -ENODEV;
 109
 110         if (port->dev_state != PORT_UNREGISTERING)
 111                 return retval;
 112
 113         device_remove_file(&port->dev, &dev_attr_port_number);
 114
 115         driver = port->serial->type;
 116         if (driver->port_remove)
 117                 retval = driver->port_remove(port);
 118
 119         minor = port->number;
 120         tty_unregister_device(usb_serial_tty_driver, minor);
 121         dev_info(dev, "%s converter now disconnected from ttyUSB%d\n",
 122                  driver->description, minor);
 123
 124         return retval;
 125 }
 126
 127 #ifdef CONFIG_HOTPLUG
 128 static ssize_t store_new_id(struct device_driver *driver,
 129                             const char *buf, size_t count)
 130 {
 131         struct usb_serial_driver *usb_drv = to_usb_serial_driver(driver);
 132         ssize_t retval = usb_store_new_id(&usb_drv->dynids, driver, buf, count);
 133
 134         if (retval >= 0 && usb_drv->usb_driver != NULL)
 135                 retval = usb_store_new_id(&usb_drv->usb_driver->dynids,
 136                                           &usb_drv->usb_driver->drvwrap.driver,
 137                                           buf, count);
 138         return retval;
 139 }
 140
 141 static struct driver_attribute drv_attrs[] = {
 142         __ATTR(new_id, S_IWUSR, NULL, store_new_id),
 143         __ATTR_NULL,
 144 };
 145
 146 static void free_dynids(struct usb_serial_driver *drv)
 147 {
 148         struct usb_dynid *dynid, *n;
 149
 150         spin_lock(&drv->dynids.lock);
 151         list_for_each_entry_safe(dynid, n, &drv->dynids.list, node) {
 152                 list_del(&dynid->node);
 153                 kfree(dynid);
 154         }
 155         spin_unlock(&drv->dynids.lock);
 156 }
 157
 158 #else
 159 static struct driver_attribute drv_attrs[] = {
 160         __ATTR_NULL,
 161 };
 162 static inline void free_dynids(struct usb_serial_driver *drv)
 163 {
 164 }
 165 #endif
 166
 167 struct bus_type usb_serial_bus_type = {
 168         .name =         "usb-serial",
 169         .match =        usb_serial_device_match,
 170         .probe =        usb_serial_device_probe,
 171         .remove =       usb_serial_device_remove,
 172         .drv_attrs =    drv_attrs,
 173 };
 174
 175 int usb_serial_bus_register(struct usb_serial_driver *driver)
 176 {
 177         int retval;
 178
 179         driver->driver.bus = &usb_serial_bus_type;
 180         spin_lock_init(&driver->dynids.lock);
 181         INIT_LIST_HEAD(&driver->dynids.list);
 182
 183         retval = driver_register(&driver->driver);
 184
 185         return retval;
 186 }
 187
 188 void usb_serial_bus_deregister(struct usb_serial_driver *driver)
 189 {
 190         free_dynids(driver);
 191         driver_unregister(&driver->driver);
 192 }
 193