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