LXR linux/drivers/usb/serial/wishbone-serial.c

   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 * USB Wishbone-Serial adapter driver
   4 *
   5 * Copyright (C) 2013 Wesley W. Terpstra <w.terpstra@gsi.de>
   6 * Copyright (C) 2013 GSI Helmholtz Centre for Heavy Ion Research GmbH
   7 */
   8
   9#include <linux/kernel.h>
  10#include <linux/tty.h>
  11#include <linux/module.h>
  12#include <linux/usb.h>
  13#include <linux/usb/serial.h>
  14#include <linux/uaccess.h>
  15
  16#define GSI_VENDOR_OPENCLOSE 0xB0
  17
  18static const struct usb_device_id id_table[] = {
  19        { USB_DEVICE_AND_INTERFACE_INFO(0x1D50, 0x6062, 0xFF, 0xFF, 0xFF) },
  20        { },
  21};
  22MODULE_DEVICE_TABLE(usb, id_table);
  23
  24/*
  25 * Etherbone must be told that a new stream has begun before data arrives.
  26 * This is necessary to restart the negotiation of Wishbone bus parameters.
  27 * Similarly, when the stream ends, Etherbone must be told so that the cycle
  28 * line can be driven low in the case that userspace failed to do so.
  29 */
  30static int usb_gsi_openclose(struct usb_serial_port *port, int value)
  31{
  32        struct usb_device *dev = port->serial->dev;
  33
  34        return usb_control_msg(
  35                dev,
  36                usb_sndctrlpipe(dev, 0), /* Send to EP0OUT */
  37                GSI_VENDOR_OPENCLOSE,
  38                USB_DIR_OUT|USB_TYPE_VENDOR|USB_RECIP_INTERFACE,
  39                value, /* wValue = device is open(1) or closed(0) */
  40                port->serial->interface->cur_altsetting->desc.bInterfaceNumber,
  41                NULL, 0,  /* There is no data stage */
  42                5000); /* Timeout till operation fails */
  43}
  44
  45static int wishbone_serial_open(struct tty_struct *tty,
  46                                struct usb_serial_port *port)
  47{
  48        int retval;
  49
  50        retval = usb_gsi_openclose(port, 1);
  51        if (retval) {
  52                dev_err(&port->serial->dev->dev,
  53                       "Could not mark device as open (%d)\n",
  54                       retval);
  55                return retval;
  56        }
  57
  58        retval = usb_serial_generic_open(tty, port);
  59        if (retval)
  60                usb_gsi_openclose(port, 0);
  61
  62        return retval;
  63}
  64
  65static void wishbone_serial_close(struct usb_serial_port *port)
  66{
  67        usb_serial_generic_close(port);
  68        usb_gsi_openclose(port, 0);
  69}
  70
  71static struct usb_serial_driver wishbone_serial_device = {
  72        .driver = {
  73                .owner =        THIS_MODULE,
  74                .name =         "wishbone_serial",
  75        },
  76        .id_table =             id_table,
  77        .num_ports =            1,
  78        .open =                 &wishbone_serial_open,
  79        .close =                &wishbone_serial_close,
  80};
  81
  82static struct usb_serial_driver * const serial_drivers[] = {
  83        &wishbone_serial_device, NULL
  84};
  85
  86module_usb_serial_driver(serial_drivers, id_table);
  87
  88MODULE_AUTHOR("Wesley W. Terpstra <w.terpstra@gsi.de>");
  89MODULE_DESCRIPTION("USB Wishbone-Serial adapter");
  90MODULE_LICENSE("GPL");
  91