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/config.h>
  12 #include <linux/kernel.h>
  13 #include <linux/errno.h>
  14 #include <linux/tty.h>
  15 #include <linux/module.h>
  16 #include <linux/usb.h>
  17 #include "usb-serial.h"
  18
  19 static int usb_serial_device_match (struct device *dev, struct device_driver *drv)
  20 {
  21         struct usb_serial_driver *driver;
  22         const struct usb_serial_port *port;
  23
  24         /*
  25          * drivers are already assigned to ports in serial_probe so it's
  26          * a simple check here.
  27          */
  28         port = to_usb_serial_port(dev);
  29         if (!port)
  30                 return 0;
  31
  32         driver = to_usb_serial_driver(drv);
  33
  34         if (driver == port->serial->type)
  35                 return 1;
  36
  37         return 0;
  38 }
  39
  40 static int usb_serial_device_probe (struct device *dev)
  41 {
  42         struct usb_serial_driver *driver;
  43         struct usb_serial_port *port;
  44         int retval = 0;
  45         int minor;
  46
  47         port = to_usb_serial_port(dev);
  48         if (!port) {
  49                 retval = -ENODEV;
  50                 goto exit;
  51         }
  52
  53         driver = port->serial->type;
  54         if (driver->port_probe) {
  55                 if (!try_module_get(driver->driver.owner)) {
  56                         dev_err(dev, "module get failed, exiting\n");
  57                         retval = -EIO;
  58                         goto exit;
  59                 }
  60                 retval = driver->port_probe (port);
  61                 module_put(driver->driver.owner);
  62                 if (retval)
  63                         goto exit;
  64         }
  65
  66         minor = port->number;
  67         tty_register_device (usb_serial_tty_driver, minor, dev);
  68         dev_info(&port->serial->dev->dev,
  69                  "%s converter now attached to ttyUSB%d\n",
  70                  driver->description, minor);
  71
  72 exit:
  73         return retval;
  74 }
  75
  76 static int usb_serial_device_remove (struct device *dev)
  77 {
  78         struct usb_serial_driver *driver;
  79         struct usb_serial_port *port;
  80         int retval = 0;
  81         int minor;
  82
  83         port = to_usb_serial_port(dev);
  84         if (!port) {
  85                 return -ENODEV;
  86         }
  87
  88         driver = port->serial->type;
  89         if (driver->port_remove) {
  90                 if (!try_module_get(driver->driver.owner)) {
  91                         dev_err(dev, "module get failed, exiting\n");
  92                         retval = -EIO;
  93                         goto exit;
  94                 }
  95                 retval = driver->port_remove (port);
  96                 module_put(driver->driver.owner);
  97         }
  98 exit:
  99         minor = port->number;
 100         tty_unregister_device (usb_serial_tty_driver, minor);
 101         dev_info(dev, "%s converter now disconnected from ttyUSB%d\n",
 102                  driver->description, minor);
 103
 104         return retval;
 105 }
 106
 107 struct bus_type usb_serial_bus_type = {
 108         .name =         "usb-serial",
 109         .match =        usb_serial_device_match,
 110         .probe =        usb_serial_device_probe,
 111         .remove =       usb_serial_device_remove,
 112 };
 113
 114 int usb_serial_bus_register(struct usb_serial_driver *driver)
 115 {
 116         int retval;
 117
 118         driver->driver.bus = &usb_serial_bus_type;
 119         retval = driver_register(&driver->driver);
 120
 121         return retval;
 122 }
 123
 124 void usb_serial_bus_deregister(struct usb_serial_driver *driver)
 125 {
 126         driver_unregister(&driver->driver);
 127 }
 128