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         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->number;
  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         int autopm_err;
 102
 103         port = to_usb_serial_port(dev);
 104         if (!port)
 105                 return -ENODEV;
 106
 107         /*
 108          * Make sure suspend/resume doesn't race against port_remove.
 109          *
 110          * Note that no further runtime PM callbacks will be made if
 111          * autopm_get fails.
 112          */
 113         autopm_err = usb_autopm_get_interface(port->serial->interface);
 114
 115         minor = port->number;
 116         tty_unregister_device(usb_serial_tty_driver, minor);
 117
 118         device_remove_file(&port->dev, &dev_attr_port_number);
 119
 120         driver = port->serial->type;
 121         if (driver->port_remove)
 122                 retval = driver->port_remove(port);
 123
 124         dev_info(dev, "%s converter now disconnected from ttyUSB%d\n",
 125                  driver->description, minor);
 126
 127         if (!autopm_err)
 128                 usb_autopm_put_interface(port->serial->interface);
 129
 130         return retval;
 131 }
 132
 133 static ssize_t store_new_id(struct device_driver *driver,
 134                             const char *buf, size_t count)
 135 {
 136         struct usb_serial_driver *usb_drv = to_usb_serial_driver(driver);
 137         ssize_t retval = usb_store_new_id(&usb_drv->dynids, driver, buf, count);
 138
 139         if (retval >= 0 && usb_drv->usb_driver != NULL)
 140                 retval = usb_store_new_id(&usb_drv->usb_driver->dynids,
 141                                           &usb_drv->usb_driver->drvwrap.driver,
 142                                           buf, count);
 143         return retval;
 144 }
 145
 146 static ssize_t show_dynids(struct device_driver *driver, char *buf)
 147 {
 148         struct usb_serial_driver *usb_drv = to_usb_serial_driver(driver);
 149
 150         return usb_show_dynids(&usb_drv->dynids, buf);
 151 }
 152
 153 static struct driver_attribute drv_attrs[] = {
 154         __ATTR(new_id, S_IRUGO | S_IWUSR, show_dynids, store_new_id),
 155         __ATTR_NULL,
 156 };
 157
 158 static void free_dynids(struct usb_serial_driver *drv)
 159 {
 160         struct usb_dynid *dynid, *n;
 161
 162         spin_lock(&drv->dynids.lock);
 163         list_for_each_entry_safe(dynid, n, &drv->dynids.list, node) {
 164                 list_del(&dynid->node);
 165                 kfree(dynid);
 166         }
 167         spin_unlock(&drv->dynids.lock);
 168 }
 169
 170 struct bus_type usb_serial_bus_type = {
 171         .name =         "usb-serial",
 172         .match =        usb_serial_device_match,
 173         .probe =        usb_serial_device_probe,
 174         .remove =       usb_serial_device_remove,
 175         .drv_attrs =    drv_attrs,
 176 };
 177
 178 int usb_serial_bus_register(struct usb_serial_driver *driver)
 179 {
 180         int retval;
 181
 182         driver->driver.bus = &usb_serial_bus_type;
 183         spin_lock_init(&driver->dynids.lock);
 184         INIT_LIST_HEAD(&driver->dynids.list);
 185
 186         retval = driver_register(&driver->driver);
 187
 188         return retval;
 189 }
 190
 191 void usb_serial_bus_deregister(struct usb_serial_driver *driver)
 192 {
 193         free_dynids(driver);
 194         driver_unregister(&driver->driver);
 195 }
 196