drivers/usb/serial/usb_debug.c

   1 /*
   2  * USB Debug cable driver
   3  *
   4  * Copyright (C) 2006 Greg Kroah-Hartman <greg@kroah.com>
   5  *
   6  *      This program is free software; you can redistribute it and/or
   7  *      modify it under the terms of the GNU General Public License version
   8  *      2 as published by the Free Software Foundation.
   9  */
  10
  11 #include <linux/gfp.h>
  12 #include <linux/kernel.h>
  13 #include <linux/init.h>
  14 #include <linux/tty.h>
  15 #include <linux/module.h>
  16 #include <linux/usb.h>
  17 #include <linux/usb/serial.h>
  18
  19 #define USB_DEBUG_MAX_PACKET_SIZE       8
  20 #define USB_DEBUG_BRK_SIZE              8
  21 static char USB_DEBUG_BRK[USB_DEBUG_BRK_SIZE] = {
  22         0x00,
  23         0xff,
  24         0x01,
  25         0xfe,
  26         0x00,
  27         0xfe,
  28         0x01,
  29         0xff,
  30 };
  31
  32 static const struct usb_device_id id_table[] = {
  33         { USB_DEVICE(0x0525, 0x127a) },
  34         { },
  35 };
  36 MODULE_DEVICE_TABLE(usb, id_table);
  37
  38 static struct usb_driver debug_driver = {
  39         .name =         "debug",
  40         .id_table =     id_table,
  41 };
  42
  43 /* This HW really does not support a serial break, so one will be
  44  * emulated when ever the break state is set to true.
  45  */
  46 static void usb_debug_break_ctl(struct tty_struct *tty, int break_state)
  47 {
  48         struct usb_serial_port *port = tty->driver_data;
  49         if (!break_state)
  50                 return;
  51         usb_serial_generic_write(tty, port, USB_DEBUG_BRK, USB_DEBUG_BRK_SIZE);
  52 }
  53
  54 static void usb_debug_process_read_urb(struct urb *urb)
  55 {
  56         struct usb_serial_port *port = urb->context;
  57
  58         if (urb->actual_length == USB_DEBUG_BRK_SIZE &&
  59                 memcmp(urb->transfer_buffer, USB_DEBUG_BRK,
  60                                                 USB_DEBUG_BRK_SIZE) == 0) {
  61                 usb_serial_handle_break(port);
  62                 return;
  63         }
  64
  65         usb_serial_generic_process_read_urb(urb);
  66 }
  67
  68 static struct usb_serial_driver debug_device = {
  69         .driver = {
  70                 .owner =        THIS_MODULE,
  71                 .name =         "debug",
  72         },
  73         .id_table =             id_table,
  74         .num_ports =            1,
  75         .bulk_out_size =        USB_DEBUG_MAX_PACKET_SIZE,
  76         .break_ctl =            usb_debug_break_ctl,
  77         .process_read_urb =     usb_debug_process_read_urb,
  78 };
  79
  80 static struct usb_serial_driver * const serial_drivers[] = {
  81         &debug_device, NULL
  82 };
  83
  84 module_usb_serial_driver(debug_driver, serial_drivers);
  85 MODULE_LICENSE("GPL");