drivers/usb/serial/bus.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * USB Serial Converter Bus specific functions
   4  *
   5  * Copyright (C) 2002 Greg Kroah-Hartman (greg@kroah.com)
   6  */
   7
   8 #include <linux/kernel.h>
   9 #include <linux/errno.h>
  10 #include <linux/tty.h>
  11 #include <linux/slab.h>
  12 #include <linux/module.h>
  13 #include <linux/usb.h>
  14 #include <linux/usb/serial.h>
  15
  16 static int usb_serial_device_match(struct device *dev,
  17                                                 struct device_driver *drv)
  18 {
  19         struct usb_serial_driver *driver;
  20         const struct usb_serial_port *port;
  21
  22         /*
  23          * drivers are already assigned to ports in serial_probe so it's
  24          * a simple check here.
  25          */
  26         port = to_usb_serial_port(dev);
  27         if (!port)
  28                 return 0;
  29
  30         driver = to_usb_serial_driver(drv);
  31
  32         if (driver == port->serial->type)
  33                 return 1;
  34
  35         return 0;
  36 }
  37
  38 static int usb_serial_device_probe(struct device *dev)
  39 {
  40         struct usb_serial_driver *driver;
  41         struct usb_serial_port *port;
  42         struct device *tty_dev;
  43         int retval = 0;
  44         int minor;
  45
  46         port = to_usb_serial_port(dev);
  47         if (!port)
  48                 return -ENODEV;
  49
  50         /* make sure suspend/resume doesn't race against port_probe */
  51         retval = usb_autopm_get_interface(port->serial->interface);
  52         if (retval)
  53                 return retval;
  54
  55         driver = port->serial->type;
  56         if (driver->port_probe) {
  57                 retval = driver->port_probe(port);
  58                 if (retval)
  59                         goto err_autopm_put;
  60         }
  61
  62         minor = port->minor;
  63         tty_dev = tty_register_device(usb_serial_tty_driver, minor, dev);
  64         if (IS_ERR(tty_dev)) {
  65                 retval = PTR_ERR(tty_dev);
  66                 goto err_port_remove;
  67         }
  68
  69         usb_autopm_put_interface(port->serial->interface);
  70
  71         dev_info(&port->serial->dev->dev,
  72                  "%s converter now attached to ttyUSB%d\n",
  73                  driver->description, minor);
  74
  75         return 0;
  76
  77 err_port_remove:
  78         if (driver->port_remove)
  79                 driver->port_remove(port);
  80 err_autopm_put:
  81         usb_autopm_put_interface(port->serial->interface);
  82
  83         return retval;
  84 }
  85
  86 static int usb_serial_device_remove(struct device *dev)
  87 {
  88         struct usb_serial_driver *driver;
  89         struct usb_serial_port *port;
  90         int retval = 0;
  91         int minor;
  92         int autopm_err;
  93
  94         port = to_usb_serial_port(dev);
  95         if (!port)
  96                 return -ENODEV;
  97
  98         /*
  99          * Make sure suspend/resume doesn't race against port_remove.
 100          *
 101          * Note that no further runtime PM callbacks will be made if
 102          * autopm_get fails.
 103          */
 104         autopm_err = usb_autopm_get_interface(port->serial->interface);
 105
 106         minor = port->minor;
 107         tty_unregister_device(usb_serial_tty_driver, minor);
 108
 109         driver = port->serial->type;
 110         if (driver->port_remove)
 111                 retval = driver->port_remove(port);
 112
 113         dev_info(dev, "%s converter now disconnected from ttyUSB%d\n",
 114                  driver->description, minor);
 115
 116         if (!autopm_err)
 117                 usb_autopm_put_interface(port->serial->interface);
 118
 119         return retval;
 120 }
 121
 122 static ssize_t new_id_store(struct device_driver *driver,
 123                             const char *buf, size_t count)
 124 {
 125         struct usb_serial_driver *usb_drv = to_usb_serial_driver(driver);
 126         ssize_t retval = usb_store_new_id(&usb_drv->dynids, usb_drv->id_table,
 127                                          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->id_table,
 132                                           &usb_drv->usb_driver->drvwrap.driver,
 133                                           buf, count);
 134         return retval;
 135 }
 136
 137 static ssize_t new_id_show(struct device_driver *driver, char *buf)
 138 {
 139         struct usb_serial_driver *usb_drv = to_usb_serial_driver(driver);
 140
 141         return usb_show_dynids(&usb_drv->dynids, buf);
 142 }
 143 static DRIVER_ATTR_RW(new_id);
 144
 145 static struct attribute *usb_serial_drv_attrs[] = {
 146         &driver_attr_new_id.attr,
 147         NULL,
 148 };
 149 ATTRIBUTE_GROUPS(usb_serial_drv);
 150
 151 static void free_dynids(struct usb_serial_driver *drv)
 152 {
 153         struct usb_dynid *dynid, *n;
 154
 155         spin_lock(&drv->dynids.lock);
 156         list_for_each_entry_safe(dynid, n, &drv->dynids.list, node) {
 157                 list_del(&dynid->node);
 158                 kfree(dynid);
 159         }
 160         spin_unlock(&drv->dynids.lock);
 161 }
 162
 163 struct bus_type usb_serial_bus_type = {
 164         .name =         "usb-serial",
 165         .match =        usb_serial_device_match,
 166         .probe =        usb_serial_device_probe,
 167         .remove =       usb_serial_device_remove,
 168         .drv_groups =   usb_serial_drv_groups,
 169 };
 170
 171 int usb_serial_bus_register(struct usb_serial_driver *driver)
 172 {
 173         int retval;
 174
 175         driver->driver.bus = &usb_serial_bus_type;
 176         spin_lock_init(&driver->dynids.lock);
 177         INIT_LIST_HEAD(&driver->dynids.list);
 178
 179         retval = driver_register(&driver->driver);
 180
 181         return retval;
 182 }
 183
 184 void usb_serial_bus_deregister(struct usb_serial_driver *driver)
 185 {
 186         free_dynids(driver);
 187         driver_unregister(&driver->driver);
 188 }
 189