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

   1/*
   2 * USB Wishbone-Serial adapter driver
   3 *
   4 * Copyright (C) 2013 Wesley W. Terpstra <w.terpstra@gsi.de>
   5 * Copyright (C) 2013 GSI Helmholtz Centre for Heavy Ion Research GmbH
   6 *
   7 * This program is free software; you can redistribute it and/or
   8 * modify it under the terms of the GNU General Public License
   9 * as published by the Free Software Foundation; either version 2
  10 * of the License, or (at your option) any later version.
  11 */
  12
  13#include <linux/kernel.h>
  14#include <linux/tty.h>
  15#include <linux/module.h>
  16#include <linux/usb.h>
  17#include <linux/usb/serial.h>
  18#include <linux/uaccess.h>
  19
  20#define GSI_VENDOR_OPENCLOSE 0xB0
  21
  22static const struct usb_device_id id_table[] = {
  23        { USB_DEVICE_AND_INTERFACE_INFO(0x1D50, 0x6062, 0xFF, 0xFF, 0xFF) },
  24        { },
  25};
  26MODULE_DEVICE_TABLE(usb, id_table);
  27
  28/*
  29 * Etherbone must be told that a new stream has begun before data arrives.
  30 * This is necessary to restart the negotiation of Wishbone bus parameters.
  31 * Similarly, when the stream ends, Etherbone must be told so that the cycle
  32 * line can be driven low in the case that userspace failed to do so.
  33 */
  34static int usb_gsi_openclose(struct usb_serial_port *port, int value)
  35{
  36        struct usb_device *dev = port->serial->dev;
  37
  38        return usb_control_msg(
  39                dev,
  40                usb_sndctrlpipe(dev, 0), /* Send to EP0OUT */
  41                GSI_VENDOR_OPENCLOSE,
  42                USB_DIR_OUT|USB_TYPE_VENDOR|USB_RECIP_INTERFACE,
  43                value, /* wValue = device is open(1) or closed(0) */
  44                port->serial->interface->cur_altsetting->desc.bInterfaceNumber,
  45                NULL, 0,  /* There is no data stage */
  46                5000); /* Timeout till operation fails */
  47}
  48
  49static int wishbone_serial_open(struct tty_struct *tty,
  50                                struct usb_serial_port *port)
  51{
  52        int retval;
  53
  54        retval = usb_gsi_openclose(port, 1);
  55        if (retval) {
  56                dev_err(&port->serial->dev->dev,
  57                       "Could not mark device as open (%d)\n",
  58                       retval);
  59                return retval;
  60        }
  61
  62        retval = usb_serial_generic_open(tty, port);
  63        if (retval)
  64                usb_gsi_openclose(port, 0);
  65
  66        return retval;
  67}
  68
  69static void wishbone_serial_close(struct usb_serial_port *port)
  70{
  71        usb_serial_generic_close(port);
  72        usb_gsi_openclose(port, 0);
  73}
  74
  75static struct usb_serial_driver wishbone_serial_device = {
  76        .driver = {
  77                .owner =        THIS_MODULE,
  78                .name =         "wishbone_serial",
  79        },
  80        .id_table =             id_table,
  81        .num_ports =            1,
  82        .open =                 &wishbone_serial_open,
  83        .close =                &wishbone_serial_close,
  84};
  85
  86static struct usb_serial_driver * const serial_drivers[] = {
  87        &wishbone_serial_device, NULL
  88};
  89
  90module_usb_serial_driver(serial_drivers, id_table);
  91
  92MODULE_AUTHOR("Wesley W. Terpstra <w.terpstra@gsi.de>");
  93MODULE_DESCRIPTION("USB Wishbone-Serial adapter");
  94MODULE_LICENSE("GPL");
  95