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/init.h>
  15#include <linux/tty.h>
  16#include <linux/module.h>
  17#include <linux/usb.h>
  18#include <linux/usb/serial.h>
  19#include <linux/uaccess.h>
  20
  21#define GSI_VENDOR_OPENCLOSE 0xB0
  22
  23static const struct usb_device_id id_table[] = {
  24        { USB_DEVICE_AND_INTERFACE_INFO(0x1D50, 0x6062, 0xFF, 0xFF, 0xFF) },
  25        { },
  26};
  27MODULE_DEVICE_TABLE(usb, id_table);
  28
  29/*
  30 * Etherbone must be told that a new stream has begun before data arrives.
  31 * This is necessary to restart the negotiation of Wishbone bus parameters.
  32 * Similarly, when the stream ends, Etherbone must be told so that the cycle
  33 * line can be driven low in the case that userspace failed to do so.
  34 */
  35static int usb_gsi_openclose(struct usb_serial_port *port, int value)
  36{
  37        struct usb_device *dev = port->serial->dev;
  38
  39        return usb_control_msg(
  40                dev,
  41                usb_sndctrlpipe(dev, 0), /* Send to EP0OUT */
  42                GSI_VENDOR_OPENCLOSE,
  43                USB_DIR_OUT|USB_TYPE_VENDOR|USB_RECIP_INTERFACE,
  44                value, /* wValue = device is open(1) or closed(0) */
  45                port->serial->interface->cur_altsetting->desc.bInterfaceNumber,
  46                NULL, 0,  /* There is no data stage */
  47                5000); /* Timeout till operation fails */
  48}
  49
  50static int wishbone_serial_open(struct tty_struct *tty,
  51                                struct usb_serial_port *port)
  52{
  53        int retval;
  54
  55        retval = usb_gsi_openclose(port, 1);
  56        if (retval) {
  57                dev_err(&port->serial->dev->dev,
  58                       "Could not mark device as open (%d)\n",
  59                       retval);
  60                return retval;
  61        }
  62
  63        retval = usb_serial_generic_open(tty, port);
  64        if (retval)
  65                usb_gsi_openclose(port, 0);
  66
  67        return retval;
  68}
  69
  70static void wishbone_serial_close(struct usb_serial_port *port)
  71{
  72        usb_serial_generic_close(port);
  73        usb_gsi_openclose(port, 0);
  74}
  75
  76static struct usb_serial_driver wishbone_serial_device = {
  77        .driver = {
  78                .owner =        THIS_MODULE,
  79                .name =         "wishbone_serial",
  80        },
  81        .id_table =             id_table,
  82        .num_ports =            1,
  83        .open =                 &wishbone_serial_open,
  84        .close =                &wishbone_serial_close,
  85};
  86
  87static struct usb_serial_driver * const serial_drivers[] = {
  88        &wishbone_serial_device, NULL
  89};
  90
  91module_usb_serial_driver(serial_drivers, id_table);
  92
  93MODULE_AUTHOR("Wesley W. Terpstra <w.terpstra@gsi.de>");
  94MODULE_DESCRIPTION("USB Wishbone-Serial adapter");
  95MODULE_LICENSE("GPL");
  96