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
  23 static const struct usb_device_id id_table[] = {
  24         { USB_DEVICE_AND_INTERFACE_INFO(0x1D50, 0x6062, 0xFF, 0xFF, 0xFF) },
  25         { },
  26 };
  27 MODULE_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  */
  35 static 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
  50 static 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
  70 static void wishbone_serial_close(struct usb_serial_port *port)
  71 {
  72         usb_serial_generic_close(port);
  73         usb_gsi_openclose(port, 0);
  74 }
  75
  76 static 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
  87 static struct usb_serial_driver * const serial_drivers[] = {
  88         &wishbone_serial_device, NULL
  89 };
  90
  91 module_usb_serial_driver(serial_drivers, id_table);
  92
  93 MODULE_AUTHOR("Wesley W. Terpstra <w.terpstra@gsi.de>");
  94 MODULE_DESCRIPTION("USB Wishbone-Serial adapter");
  95 MODULE_LICENSE("GPL");