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
  18 static const struct usb_device_id id_table[] = {
  19         { USB_DEVICE_AND_INTERFACE_INFO(0x1D50, 0x6062, 0xFF, 0xFF, 0xFF) },
  20         { },
  21 };
  22 MODULE_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  */
  30 static 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
  45 static 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
  65 static void wishbone_serial_close(struct usb_serial_port *port)
  66 {
  67         usb_serial_generic_close(port);
  68         usb_gsi_openclose(port, 0);
  69 }
  70
  71 static 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
  82 static struct usb_serial_driver * const serial_drivers[] = {
  83         &wishbone_serial_device, NULL
  84 };
  85
  86 module_usb_serial_driver(serial_drivers, id_table);
  87
  88 MODULE_AUTHOR("Wesley W. Terpstra <w.terpstra@gsi.de>");
  89 MODULE_DESCRIPTION("USB Wishbone-Serial adapter");
  90 MODULE_LICENSE("GPL");