LXR linux/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
  16static int usb_serial_device_match(struct device *dev,
  17                                                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
  32static 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
  68err_port_remove:
  69        if (driver->port_remove)
  70                driver->port_remove(port);
  71err_autopm_put:
  72        usb_autopm_put_interface(port->serial->interface);
  73
  74        return retval;
  75}
  76
  77static 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
 106static 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->drvwrap.driver,
 117                                          buf, count);
 118        return retval;
 119}
 120
 121static 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}
 127static DRIVER_ATTR_RW(new_id);
 128
 129static struct attribute *usb_serial_drv_attrs[] = {
 130        &driver_attr_new_id.attr,
 131        NULL,
 132};
 133ATTRIBUTE_GROUPS(usb_serial_drv);
 134
 135static void free_dynids(struct usb_serial_driver *drv)
 136{
 137        struct usb_dynid *dynid, *n;
 138
 139        spin_lock(&drv->dynids.lock);
 140        list_for_each_entry_safe(dynid, n, &drv->dynids.list, node) {
 141                list_del(&dynid->node);
 142                kfree(dynid);
 143        }
 144        spin_unlock(&drv->dynids.lock);
 145}
 146
 147struct bus_type usb_serial_bus_type = {
 148        .name =         "usb-serial",
 149        .match =        usb_serial_device_match,
 150        .probe =        usb_serial_device_probe,
 151        .remove =       usb_serial_device_remove,
 152        .drv_groups =   usb_serial_drv_groups,
 153};
 154
 155int usb_serial_bus_register(struct usb_serial_driver *driver)
 156{
 157        int retval;
 158
 159        driver->driver.bus = &usb_serial_bus_type;
 160        spin_lock_init(&driver->dynids.lock);
 161        INIT_LIST_HEAD(&driver->dynids.list);
 162
 163        retval = driver_register(&driver->driver);
 164
 165        return retval;
 166}
 167
 168void usb_serial_bus_deregister(struct usb_serial_driver *driver)
 169{
 170        free_dynids(driver);
 171        driver_unregister(&driver->driver);
 172}
 173
 174