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                                    const struct device_driver *drv)
  18 {
  19         const struct usb_serial_port *port = to_usb_serial_port(dev);
  20         struct usb_serial_driver *driver = to_usb_serial_driver(drv);
  21
  22         /*
  23          * drivers are already assigned to ports in serial_probe so it's
  24          * a simple check here.
  25          */
  26         if (driver == port->serial->type)
  27                 return 1;
  28
  29         return 0;
  30 }
  31
  32 static int usb_serial_device_probe(struct device *dev)
  33 {
  34         struct usb_serial_port *port = to_usb_serial_port(dev);
  35         struct usb_serial_driver *driver;
  36         struct device *tty_dev;
  37         int retval = 0;
  38         int minor;
  39
  40         /* make sure suspend/resume doesn't race against port_probe */
  41         retval = usb_autopm_get_interface(port->serial->interface);
  42         if (retval)
  43                 return retval;
  44
  45         driver = port->serial->type;
  46         if (driver->port_probe) {
  47                 retval = driver->port_probe(port);
  48                 if (retval)
  49                         goto err_autopm_put;
  50         }
  51
  52         minor = port->minor;
  53         tty_dev = tty_port_register_device(&port->port, usb_serial_tty_driver,
  54                                            minor, dev);
  55         if (IS_ERR(tty_dev)) {
  56                 retval = PTR_ERR(tty_dev);
  57                 goto err_port_remove;
  58         }
  59
  60         usb_autopm_put_interface(port->serial->interface);
  61
  62         dev_info(&port->serial->dev->dev,
  63                  "%s converter now attached to ttyUSB%d\n",
  64                  driver->description, minor);
  65
  66         return 0;
  67
  68 err_port_remove:
  69         if (driver->port_remove)
  70                 driver->port_remove(port);
  71 err_autopm_put:
  72         usb_autopm_put_interface(port->serial->interface);
  73
  74         return retval;
  75 }
  76
  77 static void usb_serial_device_remove(struct device *dev)
  78 {
  79         struct usb_serial_port *port = to_usb_serial_port(dev);
  80         struct usb_serial_driver *driver;
  81         int minor;
  82         int autopm_err;
  83
  84         /*
  85          * Make sure suspend/resume doesn't race against port_remove.
  86          *
  87          * Note that no further runtime PM callbacks will be made if
  88          * autopm_get fails.
  89          */
  90         autopm_err = usb_autopm_get_interface(port->serial->interface);
  91
  92         minor = port->minor;
  93         tty_unregister_device(usb_serial_tty_driver, minor);
  94
  95         driver = port->serial->type;
  96         if (driver->port_remove)
  97                 driver->port_remove(port);
  98
  99         dev_info(dev, "%s converter now disconnected from ttyUSB%d\n",
 100                  driver->description, minor);
 101
 102         if (!autopm_err)
 103                 usb_autopm_put_interface(port->serial->interface);
 104 }
 105
 106 static ssize_t new_id_store(struct device_driver *driver,
 107                             const char *buf, size_t count)
 108 {
 109         struct usb_serial_driver *usb_drv = to_usb_serial_driver(driver);
 110         ssize_t retval = usb_store_new_id(&usb_drv->dynids, usb_drv->id_table,
 111                                          driver, buf, count);
 112
 113         if (retval >= 0 && usb_drv->usb_driver != NULL)
 114                 retval = usb_store_new_id(&usb_drv->usb_driver->dynids,
 115                                           usb_drv->usb_driver->id_table,
 116                                           &usb_drv->usb_driver->driver,
 117                                           buf, count);
 118         return retval;
 119 }
 120
 121 static ssize_t new_id_show(struct device_driver *driver, char *buf)
 122 {
 123         struct usb_serial_driver *usb_drv = to_usb_serial_driver(driver);
 124
 125         return usb_show_dynids(&usb_drv->dynids, buf);
 126 }
 127 static DRIVER_ATTR_RW(new_id);
 128
 129 static struct attribute *usb_serial_drv_attrs[] = {
 130         &driver_attr_new_id.attr,
 131         NULL,
 132 };
 133 ATTRIBUTE_GROUPS(usb_serial_drv);
 134
 135 static void free_dynids(struct usb_serial_driver *drv)
 136 {
 137         struct usb_dynid *dynid, *n;
 138
 139         guard(mutex)(&usb_dynids_lock);
 140         list_for_each_entry_safe(dynid, n, &drv->dynids.list, node) {
 141                 list_del(&dynid->node);
 142                 kfree(dynid);
 143         }
 144 }
 145
 146 const struct bus_type usb_serial_bus_type = {
 147         .name =         "usb-serial",
 148         .match =        usb_serial_device_match,
 149         .probe =        usb_serial_device_probe,
 150         .remove =       usb_serial_device_remove,
 151         .drv_groups =   usb_serial_drv_groups,
 152 };
 153
 154 int usb_serial_bus_register(struct usb_serial_driver *driver)
 155 {
 156         int retval;
 157
 158         driver->driver.bus = &usb_serial_bus_type;
 159         INIT_LIST_HEAD(&driver->dynids.list);
 160
 161         retval = driver_register(&driver->driver);
 162
 163         return retval;
 164 }
 165
 166 void usb_serial_bus_deregister(struct usb_serial_driver *driver)
 167 {
 168         free_dynids(driver);
 169         driver_unregister(&driver->driver);
 170 }
 171