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/module.h>
  15 #include <linux/usb.h>
  16 #include <linux/usb/serial.h>
  17
  18 static int usb_serial_device_match (struct device *dev, struct device_driver *drv)
  19 {
  20         struct usb_serial_driver *driver;
  21         const struct usb_serial_port *port;
  22
  23         /*
  24          * drivers are already assigned to ports in serial_probe so it's
  25          * a simple check here.
  26          */
  27         port = to_usb_serial_port(dev);
  28         if (!port)
  29                 return 0;
  30
  31         driver = to_usb_serial_driver(drv);
  32
  33         if (driver == port->serial->type)
  34                 return 1;
  35
  36         return 0;
  37 }
  38
  39 static int usb_serial_device_probe (struct device *dev)
  40 {
  41         struct usb_serial_driver *driver;
  42         struct usb_serial_port *port;
  43         int retval = 0;
  44         int minor;
  45
  46         port = to_usb_serial_port(dev);
  47         if (!port) {
  48                 retval = -ENODEV;
  49                 goto exit;
  50         }
  51
  52         driver = port->serial->type;
  53         if (driver->port_probe) {
  54                 if (!try_module_get(driver->driver.owner)) {
  55                         dev_err(dev, "module get failed, exiting\n");
  56                         retval = -EIO;
  57                         goto exit;
  58                 }
  59                 retval = driver->port_probe (port);
  60                 module_put(driver->driver.owner);
  61                 if (retval)
  62                         goto exit;
  63         }
  64
  65         minor = port->number;
  66         tty_register_device (usb_serial_tty_driver, minor, dev);
  67         dev_info(&port->serial->dev->dev,
  68                  "%s converter now attached to ttyUSB%d\n",
  69                  driver->description, minor);
  70
  71 exit:
  72         return retval;
  73 }
  74
  75 static int usb_serial_device_remove (struct device *dev)
  76 {
  77         struct usb_serial_driver *driver;
  78         struct usb_serial_port *port;
  79         int retval = 0;
  80         int minor;
  81
  82         port = to_usb_serial_port(dev);
  83         if (!port) {
  84                 return -ENODEV;
  85         }
  86
  87         driver = port->serial->type;
  88         if (driver->port_remove) {
  89                 if (!try_module_get(driver->driver.owner)) {
  90                         dev_err(dev, "module get failed, exiting\n");
  91                         retval = -EIO;
  92                         goto exit;
  93                 }
  94                 retval = driver->port_remove (port);
  95                 module_put(driver->driver.owner);
  96         }
  97 exit:
  98         minor = port->number;
  99         tty_unregister_device (usb_serial_tty_driver, minor);
 100         dev_info(dev, "%s converter now disconnected from ttyUSB%d\n",
 101                  driver->description, minor);
 102
 103         return retval;
 104 }
 105
 106 struct bus_type usb_serial_bus_type = {
 107         .name =         "usb-serial",
 108         .match =        usb_serial_device_match,
 109         .probe =        usb_serial_device_probe,
 110         .remove =       usb_serial_device_remove,
 111 };
 112
 113 int usb_serial_bus_register(struct usb_serial_driver *driver)
 114 {
 115         int retval;
 116
 117         driver->driver.bus = &usb_serial_bus_type;
 118         retval = driver_register(&driver->driver);
 119
 120         return retval;
 121 }
 122
 123 void usb_serial_bus_deregister(struct usb_serial_driver *driver)
 124 {
 125         driver_unregister(&driver->driver);
 126 }
 127