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,
  19                                                 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 ssize_t show_port_number(struct device *dev,
  41                                 struct device_attribute *attr, char *buf)
  42 {
  43         struct usb_serial_port *port = to_usb_serial_port(dev);
  44
  45         return sprintf(buf, "%d\n", port->number - port->serial->minor);
  46 }
  47
  48 static DEVICE_ATTR(port_number, S_IRUGO, show_port_number, NULL);
  49
  50 static int usb_serial_device_probe(struct device *dev)
  51 {
  52         struct usb_serial_driver *driver;
  53         struct usb_serial_port *port;
  54         int retval = 0;
  55         int minor;
  56
  57         port = to_usb_serial_port(dev);
  58         if (!port) {
  59                 retval = -ENODEV;
  60                 goto exit;
  61         }
  62
  63         driver = port->serial->type;
  64         if (driver->port_probe) {
  65                 if (!try_module_get(driver->driver.owner)) {
  66                         dev_err(dev, "module get failed, exiting\n");
  67                         retval = -EIO;
  68                         goto exit;
  69                 }
  70                 retval = driver->port_probe(port);
  71                 module_put(driver->driver.owner);
  72                 if (retval)
  73                         goto exit;
  74         }
  75
  76         retval = device_create_file(dev, &dev_attr_port_number);
  77         if (retval)
  78                 goto exit;
  79
  80         minor = port->number;
  81         tty_register_device(usb_serial_tty_driver, minor, dev);
  82         dev_info(&port->serial->dev->dev,
  83                  "%s converter now attached to ttyUSB%d\n",
  84                  driver->description, minor);
  85
  86 exit:
  87         return retval;
  88 }
  89
  90 static int usb_serial_device_remove(struct device *dev)
  91 {
  92         struct usb_serial_driver *driver;
  93         struct usb_serial_port *port;
  94         int retval = 0;
  95         int minor;
  96
  97         port = to_usb_serial_port(dev);
  98         if (!port)
  99                 return -ENODEV;
 100
 101         device_remove_file(&port->dev, &dev_attr_port_number);
 102
 103         driver = port->serial->type;
 104         if (driver->port_remove) {
 105                 if (!try_module_get(driver->driver.owner)) {
 106                         dev_err(dev, "module get failed, exiting\n");
 107                         retval = -EIO;
 108                         goto exit;
 109                 }
 110                 retval = driver->port_remove(port);
 111                 module_put(driver->driver.owner);
 112         }
 113 exit:
 114         minor = port->number;
 115         tty_unregister_device(usb_serial_tty_driver, minor);
 116         dev_info(dev, "%s converter now disconnected from ttyUSB%d\n",
 117                  driver->description, minor);
 118
 119         return retval;
 120 }
 121
 122 #ifdef CONFIG_HOTPLUG
 123 static ssize_t store_new_id(struct device_driver *driver,
 124                             const char *buf, size_t count)
 125 {
 126         struct usb_serial_driver *usb_drv = to_usb_serial_driver(driver);
 127         ssize_t retval = usb_store_new_id(&usb_drv->dynids, driver, buf, count);
 128
 129         if (retval >= 0 && usb_drv->usb_driver != NULL)
 130                 retval = usb_store_new_id(&usb_drv->usb_driver->dynids,
 131                                           &usb_drv->usb_driver->drvwrap.driver,
 132                                           buf, count);
 133         return retval;
 134 }
 135
 136 static struct driver_attribute drv_attrs[] = {
 137         __ATTR(new_id, S_IWUSR, NULL, store_new_id),
 138         __ATTR_NULL,
 139 };
 140
 141 static void free_dynids(struct usb_serial_driver *drv)
 142 {
 143         struct usb_dynid *dynid, *n;
 144
 145         spin_lock(&drv->dynids.lock);
 146         list_for_each_entry_safe(dynid, n, &drv->dynids.list, node) {
 147                 list_del(&dynid->node);
 148                 kfree(dynid);
 149         }
 150         spin_unlock(&drv->dynids.lock);
 151 }
 152
 153 #else
 154 static struct driver_attribute drv_attrs[] = {
 155         __ATTR_NULL,
 156 };
 157 static inline void free_dynids(struct usb_serial_driver *drv)
 158 {
 159 }
 160 #endif
 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