Staging: add line6 usb driver

This is an experimental Linux driver for the guitar amp, cab, and
effects modeller PODxt Pro by Line6 (and similar devices), supporting
the following features:

  - Reading/writing individual parameters
  - Reading/writing complete channel, effects setup, and amp setup data
  - Channel switching
  - Virtual MIDI interface
  - Tuner access
  - Playback/capture/mixer device for any  ALSA-compatible PCM audio
    application
  - Signal routing (record clean/processed  guitar signal, re-amping)

Moreover, preliminary support for the Variax Workbench is included.

From: Markus Grabner <grabner@icg.tugraz.at>
Cc: Mariusz Kozlowski <m.kozlowski@tuxland.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/staging/line6/variax.h b/drivers/staging/line6/variax.h
new file mode 100644
index 0000000..286df24
--- /dev/null
+++ b/drivers/staging/line6/variax.h
@@ -0,0 +1,107 @@
+/*
+ * Line6 Linux USB driver - 0.8.0
+ *
+ * Copyright (C) 2004-2009 Markus Grabner (grabner@icg.tugraz.at)
+ *
+ *	This program is free software; you can redistribute it and/or
+ *	modify it under the terms of the GNU General Public License as
+ *	published by the Free Software Foundation, version 2.
+ *
+ */
+
+#ifndef VARIAX_H
+#define VARIAX_H
+
+
+#include "driver.h"
+
+#include <linux/spinlock.h>
+#include <linux/usb.h>
+#include <linux/wait.h>
+
+#include <sound/core.h>
+
+#include "dumprequest.h"
+
+
+#define VARIAX_ACTIVATE_DELAY 10
+#define VARIAX_STARTUP_DELAY 3
+
+
+enum {
+	VARIAX_DUMP_PASS1 = LINE6_DUMP_CURRENT,
+	VARIAX_DUMP_PASS2,
+	VARIAX_DUMP_PASS3
+};
+
+
+/**
+	 Binary Variax model dump
+*/
+struct variax_model {
+	/**
+		 Header information (including program name).
+	*/
+	unsigned char name[18];
+
+	/**
+		 Model parameters.
+	*/
+	unsigned char control[78 * 2];
+};
+
+struct usb_line6_variax {
+	/**
+		 Generic Line6 USB data.
+	*/
+	struct usb_line6 line6;
+
+	/**
+		 Dump request structure.
+		 Append two extra buffers for 3-pass data query.
+	*/
+	struct line6_dump_request dumpreq; struct line6_dump_reqbuf extrabuf[2];
+
+	/**
+		 Buffer for activation code.
+	*/
+	unsigned char *buffer_activate;
+
+	/**
+		 Model number.
+	*/
+	int model;
+
+	/**
+		 Current model settings.
+	*/
+	struct variax_model model_data;
+
+	/**
+		 Name of current model bank.
+	*/
+	unsigned char bank[18];
+
+	/**
+		 Position of volume dial.
+	*/
+	int volume;
+
+	/**
+		 Position of tone control dial.
+	*/
+	int tone;
+
+	/**
+		 Timer for delayed activation request.
+	*/
+	struct timer_list activate_timer;
+};
+
+
+extern void variax_disconnect(struct usb_interface *interface);
+extern int variax_init(struct usb_interface *interface, struct usb_line6_variax *variax);
+extern void variax_process_message(struct usb_line6_variax *variax);
+
+
+#endif