Staging: comedi: add vmk80xx USB driver

The k80xx module was completely revised again. The update contains the
following new main features:
- support for digital input
- support for digital output
- support for pulse counters
- support up to 16 boards (by the way, the windows driver and the k8055
  library (libk8055) has support for only 4 boards)

The driver can now manage all features what the board has to offer:
- analog input/output
- digital input/output
- pulse counters (read, reset, set debounce time)

I've also fixed some mistaken in the drivers source code/logic.

By testing all of the driver features i got no errors or something else.
The driver works fine....


From: Manuel Gebele <forensixs@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 1118 insertions, 0 deletions

diff --git a/drivers/staging/comedi/drivers/vmk80xx.c b/drivers/staging/comedi/drivers/vmk80xx.c
new file mode 100644
index 00000000000..64d90a16d83
--- /dev/null
+++ b/drivers/staging/comedi/drivers/vmk80xx.c
@@ -0,0 +1,1118 @@
+/*
+    comedi/drivers/vmk80xx.c
+    Velleman USB Interface Board Kernel-Space Driver
+
+    Copyright (C) 2009 Manuel Gebele <forensixs@gmx.de>, Germany
+
+    COMEDI - Linux Control and Measurement Device Interface
+    Copyright (C) 2000 David A. Schleef <ds@schleef.org>
+
+    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; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+*/
+/*
+Driver: vmk80xx
+Description: Velleman USB Interface Board Kernel-Space Driver
+Devices: K8055, K8061 (in development)
+Author: Manuel Gebele <forensixs@gmx.de>
+Updated: Tue, 21 Apr 2009 19:40:55 +0200
+Status: works
+*/
+
+#include <linux/kernel.h>
+#include <linux/comedidev.h> /* comedi definitions */
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/errno.h>
+#include <linux/input.h>
+#include <linux/slab.h>
+#include <linux/poll.h>
+#include <linux/usb.h>
+#include <asm/uaccess.h>
+
+/* ------------------------------------------------------------------------ */
+#define VMK80XX_MODULE_DESC "Velleman USB Interface Board Kernel-Space Driver"
+#define VMK80XX_MODULE_DEVICE "Velleman K8055/K8061 USB Interface Board"
+#define VMK80XX_MODULE_AUTHOR "Copyright (C) 2009 Manuel Gebele, Germany"
+#define VMK80XX_MODULE_LICENSE "GPL"
+#define VMK80XX_MODULE_VERSION "0.7.76"
+
+/* Module device ID's */
+static struct usb_device_id vm_id_table[] = {
+	/* k8055 */
+	{ USB_DEVICE(0x10cf, 0x5500 + 0x00) }, /* @ddr. 0 */
+	{ USB_DEVICE(0x10cf, 0x5500 + 0x01) }, /* @ddr. 1 */
+	{ USB_DEVICE(0x10cf, 0x5500 + 0x02) }, /* @ddr. 2 */
+	{ USB_DEVICE(0x10cf, 0x5500 + 0x03) }, /* @ddr. 3 */
+	/* k8061 */
+	{ USB_DEVICE(0x10cf, 0x8061 + 0x00) }, /* @ddr. 0 */
+	{ USB_DEVICE(0x10cf, 0x8061 + 0x01) }, /* @ddr. 1 */
+	{ USB_DEVICE(0x10cf, 0x8061 + 0x02) }, /* @ddr. 2 */
+	{ USB_DEVICE(0x10cf, 0x8061 + 0x03) }, /* @ddr. 3 */
+	{ USB_DEVICE(0x10cf, 0x8061 + 0x04) }, /* @ddr. 4 */
+	{ USB_DEVICE(0x10cf, 0x8061 + 0x05) }, /* @ddr. 5 */
+	{ USB_DEVICE(0x10cf, 0x8061 + 0x06) }, /* @ddr. 6 */
+	{ USB_DEVICE(0x10cf, 0x8061 + 0x07) }, /* @ddr. 7 */
+	{ } /* terminating entry */
+};
+MODULE_DEVICE_TABLE(usb, vm_id_table);
+
+MODULE_AUTHOR(VMK80XX_MODULE_AUTHOR);
+MODULE_DESCRIPTION(VMK80XX_MODULE_DESC);
+MODULE_SUPPORTED_DEVICE(VMK80XX_MODULE_DEVICE);
+MODULE_VERSION(VMK80XX_MODULE_VERSION);
+MODULE_LICENSE(VMK80XX_MODULE_LICENSE);
+/* ------------------------------------------------------------------------ */
+
+#define CONFIG_VMK80XX_DEBUG
+
+//#undef CONFIG_COMEDI_DEBUG /* Uncommend this line to disable comedi debug */
+#undef CONFIG_VMK80XX_DEBUG  /* Commend this line to enable vmk80xx debug */
+
+#ifdef CONFIG_COMEDI_DEBUG
+ static int cm_dbg = 1;
+#else   /* !CONFIG_COMEDI_DEBUG */
+ static int cm_dbg = 0;
+#endif  /* !CONFIG_COMEDI_DEBUG */
+
+#ifdef CONFIG_VMK80XX_DEBUG
+ static int vm_dbg = 1;
+#else   /* !CONFIG_VMK80XX_DEBUG */
+ static int vm_dbg = 0;
+#endif  /* !CONFIG_VMK80XX_DEBUG */
+
+/* Define our own debug macros */
+#define DBGCM(fmt, arg...) do { if (cm_dbg) printk(fmt, ##arg); } while (0)
+#define DBGVM(fmt, arg...) do { if (vm_dbg) printk(fmt, ##arg); } while (0)
+
+/* Velleman K8055 specific stuff */
+#define VMK8055_DI              0 /* digital input offset */
+#define VMK8055_DO              1 /* digital output offset */
+#define VMK8055_AO1             2 /* analog output channel 1 offset */
+#define VMK8055_AO2             3 /* analog output channel 2 offset */
+#define VMK8055_CNT1            4 /* counter 1 offset */
+#define VMK8055_CNT2            6 /* counter 2 offset */
+#define VMK8055_CMD_RST      0x00 /* reset device registers */
+#define VMK8055_CMD_DEB1     0x01 /* debounce time for pulse counter 1 */
+#define VMK8055_CMD_DEB2     0x02 /* debounce time for pulse counter 2 */
+#define VMK8055_CMD_RST_CNT1 0x03 /* reset pulse counter 1 */
+#define VMK8055_CMD_RST_CNT2 0x04 /* reset pulse counter 2 */
+#define VMK8055_CMD_AD       0x05 /* write to analog or digital channel */
+#define VMK8055_EP_OUT       0x01 /* out endpoint address */
+#define VMK8055_EP_IN        0x81 /* in endpoint address */
+#define VMK8055_EP_SIZE         8 /* endpoint max packet size */
+#define VMK8055_EP_INTERVAL    20 /* general conversion time per command */
+#define VMK8055_MAX_BOARDS     16
+
+/* Structure to hold all of our device specific stuff */
+struct vmk80xx_usb {
+	struct usb_interface	*intf;
+	struct semaphore	limit_sem;
+	wait_queue_head_t	read_wait;
+	wait_queue_head_t	write_wait;
+	size_t			irq_out_endpoint_size;
+	__u8			irq_out_endpoint;
+	int			irq_out_interval;
+	unsigned char		*irq_out_buf;
+	struct urb		*irq_out_urb;
+	int			irq_out_busy;
+	size_t			irq_in_endpoint_size;
+	__u8			irq_in_endpoint;
+	int			irq_in_interval;
+	unsigned char		*irq_in_buf;
+	struct urb		*irq_in_urb;
+	int			irq_in_busy;
+	int			irq_in_running;
+	int			probed;
+	int			attached;
+	int			id;
+};
+
+static struct vmk80xx_usb vm_boards[VMK8055_MAX_BOARDS];
+
+/* ---------------------------------------------------------------------------
+ * Abort active transfers and tidy up allocated resources.
+--------------------------------------------------------------------------- */
+static void vm_abort_transfers(struct vmk80xx_usb *vm)
+{
+	DBGVM("comedi#: vmk80xx: %s\n", __func__);
+
+	if (vm->irq_in_running) {
+		vm->irq_in_running = 0;
+		if (vm->intf)
+			usb_kill_urb(vm->irq_in_urb);
+	}
+
+	if (vm->irq_out_busy && vm->intf)
+		usb_kill_urb(vm->irq_out_urb);
+}
+
+static void vm_delete(struct vmk80xx_usb *vm)
+{
+	DBGVM("comedi#: vmk80xx: %s\n", __func__);
+
+	vm_abort_transfers(vm);
+
+	/* Deallocate usb urbs and kernel buffers */
+	if (vm->irq_in_urb)
+		usb_free_urb(vm->irq_in_urb);
+
+	if (vm->irq_out_urb);
+		usb_free_urb(vm->irq_out_urb);
+
+	if (vm->irq_in_buf)
+		kfree(vm->irq_in_buf);
+
+	if (vm->irq_out_buf)
+		kfree(vm->irq_out_buf);
+}
+
+/* ---------------------------------------------------------------------------
+ * Interrupt in and interrupt out callback for usb data transfer.
+--------------------------------------------------------------------------- */
+static void vm_irq_in_callback(struct urb *urb)
+{
+	struct vmk80xx_usb *vm = (struct vmk80xx_usb *)urb->context;
+	int err;
+
+	DBGVM("comedi#: vmk80xx: %s\n", __func__);
+
+	switch (urb->status) {
+	case 0: /* success */
+		break;
+	case -ENOENT:
+	case -ECONNRESET:
+	case -ESHUTDOWN:
+		break;
+	default:
+		DBGCM("comedi#: vmk80xx: %s - nonzero urb status (%d)\n",
+		      __func__, urb->status);
+		goto resubmit; /* maybe we can recover */
+	}
+
+	goto exit;
+resubmit:
+	if (vm->irq_in_running && vm->intf) {
+		err = usb_submit_urb(vm->irq_in_urb, GFP_ATOMIC);
+		if (!err) goto exit;
+		/* FALL THROUGH */
+		DBGCM("comedi#: vmk80xx: %s - submit urb failed (err# %d)\n",
+		      __func__, err);
+	}
+exit:
+	vm->irq_in_busy = 0;
+
+	/* interrupt-in pipe is available again */
+	wake_up_interruptible(&vm->read_wait);
+}
+
+static void vm_irq_out_callback(struct urb *urb)
+{
+	struct vmk80xx_usb *vm;
+
+	DBGVM("comedi#: vmk80xx: %s\n", __func__);
+
+	/* sync/async unlink (hardware going away) faults  aren't errors */
+	if (urb->status && !(urb->status == -ENOENT
+			||   urb->status == -ECONNRESET
+			||   urb->status == -ESHUTDOWN))
+		DBGCM("comedi#: vmk80xx: %s - nonzero urb status (%d)\n",
+		      __func__, urb->status);
+
+	vm = (struct vmk80xx_usb *)urb->context;
+	vm->irq_out_busy = 0;
+
+	/* interrupt-out pipe is available again */
+	wake_up_interruptible(&vm->write_wait);
+}
+
+/* ---------------------------------------------------------------------------
+ * Interface for digital/analog input/output and counter funcs (see below).
+--------------------------------------------------------------------------- */
+static int vm_read(struct vmk80xx_usb *vm)
+{
+	struct usb_device *udev;
+	int retval = -ENODEV;
+
+	DBGVM("comedi#: vmk80xx: %s\n", __func__);
+
+	/* Verify that the device wasn't un-plugged */
+	if (!vm->intf) {
+		DBGCM("comedi#: vmk80xx: %s - No dev or dev un-plugged\n",
+		      __func__);
+		goto exit;
+	}
+
+	if (vm->irq_in_busy) {
+		retval = wait_event_interruptible(vm->read_wait,
+						 !vm->irq_in_busy);
+		if (retval < 0) { /* we were interrupted by a signal */
+			retval = -ERESTART;
+			goto exit;
+		}
+	}
+
+	udev = interface_to_usbdev(vm->intf);
+
+	/* Fill the urb and send off */
+	usb_fill_int_urb(vm->irq_in_urb,
+			 udev,
+			 usb_rcvintpipe(udev, vm->irq_in_endpoint),
+			 vm->irq_in_buf,
+			 vm->irq_in_endpoint_size,
+			 vm_irq_in_callback,
+			 vm,
+			 vm->irq_in_interval);
+
+	vm->irq_in_running = 1;
+	vm->irq_in_busy = 1; /* disallow following read request's */
+
+	retval = usb_submit_urb(vm->irq_in_urb, GFP_KERNEL);
+	if (!retval) goto exit; /* success */
+	/* FALL TROUGH */
+	vm->irq_in_running = 0;
+	DBGCM("comedi#: vmk80xx: %s - submit urb failed (err# %d)\n",
+	      __func__, retval);
+
+exit:
+	return retval;
+}
+
+static int vm_write(struct vmk80xx_usb *vm, unsigned char cmd)
+{
+	struct usb_device *udev;
+	int retval = -ENODEV;
+
+	DBGVM("comedi#: vmk80xx: %s\n", __func__);
+
+	/* Verify that the device wasn't un-plugged */
+	if (!vm->intf) {
+		DBGCM("comedi#: vmk80xx: %s - No dev or dev un-plugged\n",
+		      __func__);
+		goto exit;
+	}
+
+	if (vm->irq_out_busy) {
+		retval = wait_event_interruptible(vm->write_wait,
+						 !vm->irq_out_busy);
+		if (retval < 0) { /* we were interrupted by a signal */
+			retval = -ERESTART;
+			goto exit;
+		}
+	}
+
+	udev = interface_to_usbdev(vm->intf);
+
+	/* Set the command which should send to the device */
+	vm->irq_out_buf[0] = cmd;
+
+	/* Fill the urb and send off */
+	usb_fill_int_urb(vm->irq_out_urb,
+			 udev,
+			 usb_sndintpipe(udev, vm->irq_out_endpoint),
+			 vm->irq_out_buf,
+			 vm->irq_out_endpoint_size,
+			 vm_irq_out_callback,
+			 vm,
+			 vm->irq_out_interval);
+
+	vm->irq_out_busy = 1; /* disallow following write request's */
+
+	wmb();
+
+	retval = usb_submit_urb(vm->irq_out_urb, GFP_KERNEL);
+	if (!retval) goto exit; /* success */
+	/* FALL THROUGH */
+	vm->irq_out_busy = 0;
+	DBGCM("comedi#: vmk80xx: %s - submit urb failed (err# %d)\n",
+	      __func__, retval);
+
+exit:
+	return retval;
+}
+
+/* ---------------------------------------------------------------------------
+ * COMEDI-Interface (callback functions for the userspacs apps).
+--------------------------------------------------------------------------- */
+static int vm_ai_rinsn(comedi_device *dev, comedi_subdevice *s,
+		       comedi_insn *insn, unsigned int *data)
+{
+	struct vmk80xx_usb *vm;
+	int minor = dev->minor;
+	int ch, ch_offs, i;
+	int retval = -EFAULT;
+
+	DBGVM("comedi%d: vmk80xx: %s\n", minor,  __func__);
+
+	if (!(vm = (struct vmk80xx_usb *)dev->private))
+		return retval;
+
+	down(&vm->limit_sem);
+
+	/* We have an attached board ? */
+	if (!vm->probed) {
+		retval = -ENODEV;
+		goto error;
+	}
+
+	/* interrupt-in pipe busy ? */
+	if (vm->irq_in_busy) {
+		retval = -EBUSY;
+		goto error;
+	}
+
+	ch = CR_CHAN(insn->chanspec);
+	ch_offs = (!ch) ? VMK8055_AO1 : VMK8055_AO2;
+
+	for (i = 0; i < insn->n; i++) {
+		retval = vm_read(vm);
+		if (retval)
+			goto error;
+
+		/* NOTE:
+		 * The input voltage of the selected 8-bit AD channel
+		 * is converted to a value which lies between
+		 * 0 and 255.
+		 */
+		data[i] = vm->irq_in_buf[ch_offs];
+	}
+
+	up(&vm->limit_sem);
+
+	/* Return the number of samples read */
+	return i;
+error:
+	up(&vm->limit_sem);
+
+	return retval;
+}
+
+static int vm_ao_winsn(comedi_device *dev, comedi_subdevice *s,
+                       comedi_insn *insn, unsigned int *data)
+{
+	struct vmk80xx_usb *vm;
+	int minor = dev->minor;
+	int ch, ch_offs, i;
+	int retval = -EFAULT;
+
+	DBGVM("comedi%d: vmk80xx: %s\n", minor,  __func__);
+
+	if (!(vm = (struct vmk80xx_usb *)dev->private))
+		return retval;
+
+	down(&vm->limit_sem);
+
+	/* We have an attached board ? */
+	if (!vm->probed) {
+		retval = -ENODEV;
+		goto error;
+	}
+
+	/* interrupt-out pipe busy ? */
+	if (vm->irq_out_busy) {
+		retval = -EBUSY;
+		goto error;
+	}
+
+	ch = CR_CHAN(insn->chanspec);
+	ch_offs = (!ch) ? VMK8055_AO1 : VMK8055_AO2;
+
+	for (i = 0; i < insn->n; i++) {
+		/* NOTE:
+		 * The indicated 8-bit DA channel is altered according
+		 * to the new data. This means that the data corresponds
+		 * to a specific voltage. The value 0 corresponds to a
+		 * minimum output voltage (+-0 Volt) and the value 255
+		 * corresponds to a maximum output voltage (+5 Volt).
+		 */
+		vm->irq_out_buf[ch_offs] = data[i];
+
+		retval = vm_write(vm, VMK8055_CMD_AD);
+		if (retval)
+			goto error;
+	}
+
+	up(&vm->limit_sem);
+
+	/* Return the number of samples write */
+	return i;
+error:
+	up(&vm->limit_sem);
+
+	return retval;
+}
+
+static int vm_di_rinsn(comedi_device *dev, comedi_subdevice *s,
+		       comedi_insn *insn, unsigned int *data)
+{
+	struct vmk80xx_usb *vm;
+	int minor = dev->minor;
+	int ch, i, inp;
+	int retval = -EFAULT;
+
+	DBGVM("comedi%d: vmk80xx: %s\n", minor,  __func__);
+
+	if (!(vm = (struct vmk80xx_usb *)dev->private))
+		return retval;
+
+	down(&vm->limit_sem);
+
+	/* We have an attached board ? */
+	if (!vm->probed) {
+		retval = -ENODEV;
+		goto error;
+	}
+
+	/* interrupt-in pipe busy ? */
+	if (vm->irq_in_busy) {
+		retval = -EBUSY;
+		goto error;
+	}
+
+	for (i = 0, ch = CR_CHAN(insn->chanspec); i < insn->n; i++) {
+		retval = vm_read(vm);
+		if (retval)
+			goto error;
+
+		/* NOTE:
+		 * The status of the selected digital input channel is read.
+		 */
+		inp = (((vm->irq_in_buf[VMK8055_DI] >> 4) & 0x03) |
+		       ((vm->irq_in_buf[VMK8055_DI] << 2) & 0x04) |
+		       ((vm->irq_in_buf[VMK8055_DI] >> 3) & 0x18));
+		data[i] = ((inp & (1 << ch)) > 0);
+	}
+
+	up(&vm->limit_sem);
+
+	return i;
+error:
+	up(&vm->limit_sem);
+
+	return retval;
+}
+
+static int vm_do_winsn(comedi_device *dev, comedi_subdevice *s,
+		       comedi_insn *insn, unsigned int *data)
+{
+	struct vmk80xx_usb *vm;
+	int minor = dev->minor;
+	int ch, i, mask;
+	int retval = -EFAULT;
+
+	DBGVM("comedi%d: vmk80xx: %s\n", minor,  __func__);
+
+	if (!(vm = (struct vmk80xx_usb *)dev->private))
+		return retval;
+
+	down(&vm->limit_sem);
+
+	/* We have an attached board ? */
+	if (!vm->probed) {
+		retval = -ENODEV;
+		goto error;
+	}
+
+	/* interrupt-out pipe busy ? */
+	if (vm->irq_out_busy) {
+		retval = -EBUSY;
+		goto error;
+	}
+
+	for (i = 0, ch = CR_CHAN(insn->chanspec); i < insn->n; i++) {
+		/* NOTE:
+		 * The selected digital output channel is set or cleared.
+		 */
+		mask = (data[i] == 1)
+		     ? vm->irq_out_buf[VMK8055_DO] | (1 << ch)
+		     : vm->irq_out_buf[VMK8055_DO] ^ (1 << ch);
+
+		vm->irq_out_buf[VMK8055_DO] = mask;
+
+		retval = vm_write(vm, VMK8055_CMD_AD);
+		if (retval)
+			goto error;
+	}
+
+	up(&vm->limit_sem);
+
+	return i;
+error:
+	up(&vm->limit_sem);
+
+	return retval;
+}
+
+static int vm_cnt_rinsn(comedi_device *dev, comedi_subdevice *s,
+			comedi_insn *insn, unsigned int *data)
+{
+	struct vmk80xx_usb *vm;
+	int minor = dev->minor;
+	int cnt, cnt_offs, i;
+	int retval = -EFAULT;
+
+	DBGVM("comedi%d: vmk80xx: %s\n", minor,  __func__);
+
+	if (!(vm = (struct vmk80xx_usb *)dev->private))
+		return retval;
+
+	down(&vm->limit_sem);
+
+	/* We have an attached board ? */
+	if (!vm->probed) {
+		retval = -ENODEV;
+		goto error;
+	}
+
+	/* interrupt-in pipe busy ? */
+	if (vm->irq_in_busy) {
+		retval = -EBUSY;
+		goto error;
+	}
+
+	cnt = CR_CHAN(insn->chanspec);
+	cnt_offs = (!cnt) ? VMK8055_CNT1 : VMK8055_CNT2;
+
+	for (i = 0; i < insn->n; i++) {
+		retval = vm_read(vm);
+		if (retval)
+			goto error;
+
+		/* NOTE:
+		 * The status of the selected 16-bit pulse counter is
+		 * read. The counter # 1 counts the pulses fed to the
+		 * input Inp1 and the counter # 2 counts the pulses fed
+		 * to the input Inp2.
+		 */
+		data[i] = vm->irq_in_buf[cnt_offs];
+	}
+
+	up(&vm->limit_sem);
+
+	return i;
+error:
+	up(&vm->limit_sem);
+
+	return retval;
+}
+
+static int vm_cnt_winsn(comedi_device *dev, comedi_subdevice *s,
+			comedi_insn *insn, unsigned int *data)
+{
+	struct vmk80xx_usb *vm;
+	int minor = dev->minor;
+	int cnt, cnt_offs, cmd, i;
+	int retval = -EFAULT;
+
+	DBGVM("comedi%d: vmk80xx: %s\n", minor,  __func__);
+
+	if (!(vm = (struct vmk80xx_usb *)dev->private))
+		return retval;
+
+	down(&vm->limit_sem);
+
+	/* We have an attached board ? */
+	if (!vm->probed) {
+		retval = -ENODEV;
+		goto error;
+	}
+
+	/* interrupt-out pipe busy ? */
+	if (vm->irq_out_busy) {
+		retval = -EBUSY;
+		goto error;
+	}
+
+	cnt = CR_CHAN(insn->chanspec);
+	cnt_offs = (!cnt) ? VMK8055_CNT1 : VMK8055_CNT2;
+	cmd = (!cnt) ? VMK8055_CMD_RST_CNT1 : VMK8055_CMD_RST_CNT2;
+
+	for (i = 0; i < insn->n; i++) {
+		/* NOTE:
+		 * The selected 16-bit pulse counter is reset.
+		 */
+		vm->irq_out_buf[cnt_offs] = 0x00;
+
+		retval = vm_write(vm, cmd);
+		if (retval)
+			goto error;
+	}
+
+	up(&vm->limit_sem);
+
+	return i;
+error:
+	up(&vm->limit_sem);
+
+	return retval;
+}
+
+static int vm_cnt_cinsn(comedi_device *dev, comedi_subdevice *s,
+			comedi_insn *insn, unsigned int *data)
+{
+	struct vmk80xx_usb *vm;
+	int minor = dev->minor;
+	int cnt, cmd, i;
+	unsigned int debtime, val;
+	int retval = -EFAULT;
+
+	DBGVM("comedi%d: vmk80xx: %s\n", minor,  __func__);
+
+	if (!(vm = (struct vmk80xx_usb *)dev->private))
+		return retval;
+
+	down(&vm->limit_sem);
+
+	/* We have an attached board ? */
+	if (!vm->probed) {
+		retval = -ENODEV;
+		goto error;
+	}
+
+	/* interrupt-out pipe busy ? */
+	if (vm->irq_out_busy) {
+		retval = -EBUSY;
+		goto error;
+	}
+
+	cnt = CR_CHAN(insn->chanspec);
+	cmd = (!cnt) ? VMK8055_CMD_DEB1 : VMK8055_CMD_DEB2;
+
+	/* NOTE:
+	 * The counter inputs are debounced in the software to prevent
+	 * false triggering when mechanical switches or relay inputs
+	 * are used. The debounce time is equal for both falling and
+	 * rising edges. The default debounce time is 2ms. This means
+	 * the counter input must be stable for at least 2ms before it
+	 * is recognised , giving the maximum count rate of about 200
+	 * counts per second. If the debounce time is set to 0, then
+	 * the maximum counting rate is about 2000 counts per second.
+	 */
+	for (i = 0; i < insn->n; i++) {
+		debtime = data[i];
+		if (debtime == 0)
+			debtime = 1;
+		/* --------------------------------------------------
+		 * From libk8055.c
+		 * ---------------
+		 * Copyleft (C) 2005 by Sven Lindberg;
+		 * Copyright (C) 2007 by Pjetur G. Hjaltason:
+		 * By testing and measuring on the other hand I found
+		 * the formula dbt=0.115*x^2.........
+		 *
+		 * I'm using here an adapted formula to avoid floating
+		 * point operations inside the kernel. The time set
+		 * with this formula is within +-4% +- 1.
+		 * ------------------------------------------------ */
+		val = int_sqrt(debtime * 1000 / 115);
+		if (((val + 1) * val) < debtime * 1000 / 115)
+			val += 1;
+
+		vm->irq_out_buf[cnt+6] = val;
+
+		retval = vm_write(vm, cmd);
+		if (retval)
+			goto error;
+	}
+
+	up(&vm->limit_sem);
+
+	return i;
+error:
+	up(&vm->limit_sem);
+
+	return retval;
+}
+
+/* Comedi subdevice offsets */
+#define VMK8055_SUBD_AI_OFFSET	0
+#define VMK8055_SUBD_AO_OFFSET	1
+#define VMK8055_SUBD_DI_OFFSET	2
+#define VMK8055_SUBD_DO_OFFSET	3
+#define VMK8055_SUBD_CT_OFFSET	4
+
+static DEFINE_MUTEX(glb_mutex);
+
+/* ---------------------------------------------------------------------------
+ * Hook-up (or deallocate) the virtual device file '/dev/comedi[minor]' with
+ * the vmk80xx driver (comedi_config/rmmod).
+--------------------------------------------------------------------------- */
+static int vm_attach(comedi_device *dev, comedi_devconfig *it)
+{
+	comedi_subdevice *s;
+	int minor = dev->minor;
+	int idx, i;
+
+	DBGVM("comedi%d: vmk80xx: %s\n", minor,  __func__);
+
+	mutex_lock(&glb_mutex);
+
+	/* Prepare user info... */
+	printk("comedi%d: vmk80xx: ", minor);
+
+	idx = -1;
+
+	/* Find the last valid device which has been detected
+	 * by the probe function */;
+	for (i = 0; i < VMK8055_MAX_BOARDS; i++)
+		if (vm_boards[i].probed && !vm_boards[i].attached) {
+			idx = i;
+			break;
+		}
+
+	if (idx == -1) {
+		printk("no boards attached\n");
+		mutex_unlock(&glb_mutex);
+		return -ENODEV;
+	}
+
+	down(&vm_boards[idx].limit_sem);
+
+	/* OK, at that time we've an attached board and this is
+	 * the first execution of the comedi_config command for
+	 * this board */
+	printk("board #%d is attached to comedi\n", vm_boards[idx].id);
+
+	dev->board_name = "vmk80xx";
+	dev->private = vm_boards + idx; /* will be allocated in vm_probe */
+
+	/* Subdevices section -> set properties */
+	if (alloc_subdevices(dev, 5) < 0) {
+		printk("comedi%d: vmk80xx: couldn't allocate subdevs\n",
+		       minor);
+		up(&vm_boards[idx].limit_sem);
+		mutex_unlock(&glb_mutex);
+		return -ENOMEM;
+	}
+
+	s = dev->subdevices + VMK8055_SUBD_AI_OFFSET;
+	s->type = COMEDI_SUBD_AI;
+	s->subdev_flags = SDF_READABLE | SDF_GROUND;
+	s->n_chan = 2;
+	s->maxdata = 0xff; /* +5 Volt */
+	s->range_table = &range_unipolar5; /* +-0 Volt - +5 Volt */
+	s->insn_read = vm_ai_rinsn;
+
+	s = dev->subdevices + VMK8055_SUBD_AO_OFFSET;
+	s->type = COMEDI_SUBD_AO;
+	s->subdev_flags = SDF_WRITEABLE | SDF_GROUND;
+	s->n_chan = 2;
+	s->maxdata = 0xff;
+	s->range_table = &range_unipolar5;
+	s->insn_write = vm_ao_winsn;
+
+	s = dev->subdevices + VMK8055_SUBD_DI_OFFSET;
+	s->type = COMEDI_SUBD_DI;
+	s->subdev_flags = SDF_READABLE | SDF_GROUND;
+	s->n_chan = 5;
+	s->insn_read = vm_di_rinsn;
+
+	s = dev->subdevices + VMK8055_SUBD_DO_OFFSET;
+	s->type = COMEDI_SUBD_DO;
+	s->subdev_flags = SDF_WRITEABLE | SDF_GROUND;
+	s->n_chan = 8;
+	s->maxdata = 1;
+	s->insn_write = vm_do_winsn;
+
+	s = dev->subdevices + VMK8055_SUBD_CT_OFFSET;
+	s->type = COMEDI_SUBD_COUNTER;
+	s->subdev_flags = SDF_READABLE | SDF_WRITEABLE;
+	s->n_chan = 2;
+	s->insn_read = vm_cnt_rinsn;
+	s->insn_write = vm_cnt_winsn; /* accept only a channel # as arg */
+	s->insn_config = vm_cnt_cinsn;
+
+	/* Register the comedi board connection */
+	vm_boards[idx].attached = 1;
+
+	up(&vm_boards[idx].limit_sem);
+
+	mutex_unlock(&glb_mutex);
+
+	return 0;
+}
+
+static int vm_detach(comedi_device *dev)
+{
+	struct vmk80xx_usb *vm;
+	int minor = dev->minor;
+
+	DBGVM("comedi%d: vmk80xx: %s\n", minor,  __func__);
+
+	if (!dev) { /* FIXME: I don't know if i need that here */
+		printk("comedi%d: vmk80xx: %s - dev is NULL\n",
+		       minor, __func__);
+		return -EFAULT;
+	}
+
+	if (!(vm = (struct vmk80xx_usb *)dev->private)) {
+		printk("comedi%d: vmk80xx: %s - dev->private is NULL\n",
+		       minor, __func__);
+		return -EFAULT;
+	}
+
+	/* NOTE: dev->private and dev->subdevices are deallocated
+	 * automatically by the comedi core */
+
+	down(&vm->limit_sem);
+
+	dev->private = NULL;
+	vm->attached = 0;
+
+	printk("comedi%d: vmk80xx: board #%d removed from comedi core\n",
+	       minor, vm->id);
+
+	up(&vm->limit_sem);
+
+	return 0;
+}
+
+/* ---------------------------------------------------------------------------
+ * Hook-up or remove the Velleman board from the usb.
+--------------------------------------------------------------------------- */
+static int vm_probe(struct usb_interface *itf, const struct usb_device_id *id)
+{
+	struct usb_device *udev;
+	int idx, i;
+	u16 product_id;
+	int retval = -ENOMEM;
+
+	DBGVM("comedi#: vmk80xx: %s\n", __func__);
+
+	mutex_lock(&glb_mutex);
+
+	udev = interface_to_usbdev(itf);
+
+	idx = -1;
+
+	/* TODO: k8061 only theoretically supported yet */
+	product_id = le16_to_cpu(udev->descriptor.idProduct);
+	if (product_id == 0x8061) {
+		printk("comedi#: vmk80xx: Velleman K8061 detected "
+		       "(no COMEDI support available yet)\n");
+		mutex_unlock(&glb_mutex);
+		return -ENODEV;
+	}
+
+	/* Look for a free place to put the board into the array */
+	for (i = 0; i < VMK8055_MAX_BOARDS; i++) {
+		if (!vm_boards[i].probed) {
+			idx = i;
+			i = VMK8055_MAX_BOARDS;
+		}
+	}
+
+	if (idx == -1) {
+		printk("comedi#: vmk80xx: only FOUR boards supported\n");
+		mutex_unlock(&glb_mutex);
+		return -EMFILE;
+	}
+
+	/* Initialize device states (hard coded) */
+	vm_boards[idx].intf = itf;
+
+	/* interrupt-in context */
+	vm_boards[idx].irq_in_endpoint = VMK8055_EP_IN;
+	vm_boards[idx].irq_in_interval = VMK8055_EP_INTERVAL;
+	vm_boards[idx].irq_in_endpoint_size = VMK8055_EP_SIZE;
+	vm_boards[idx].irq_in_buf = kmalloc(VMK8055_EP_SIZE, GFP_KERNEL);
+	if (!vm_boards[idx].irq_in_buf) {
+		err("comedi#: vmk80xx: couldn't alloc irq_in_buf\n");
+		goto error;
+	}
+
+	/* interrupt-out context */
+	vm_boards[idx].irq_out_endpoint = VMK8055_EP_OUT;
+	vm_boards[idx].irq_out_interval = VMK8055_EP_INTERVAL;
+	vm_boards[idx].irq_out_endpoint_size = VMK8055_EP_SIZE;
+	vm_boards[idx].irq_out_buf = kmalloc(VMK8055_EP_SIZE, GFP_KERNEL);
+	if (!vm_boards[idx].irq_out_buf) {
+		err("comedi#: vmk80xx: couldn't alloc irq_out_buf\n");
+		goto error;
+	}
+
+	/* Endpoints located ? */
+	if (!vm_boards[idx].irq_in_endpoint) {
+		err("comedi#: vmk80xx: int-in endpoint not found\n");
+		goto error;
+	}
+
+	if (!vm_boards[idx].irq_out_endpoint) {
+		err("comedi#: vmk80xx: int-out endpoint not found\n");
+		goto error;
+	}
+
+	/* Try to allocate in/out urbs */
+	vm_boards[idx].irq_in_urb = usb_alloc_urb(0, GFP_KERNEL);
+	if (!vm_boards[idx].irq_in_urb) {
+		err("comedi#: vmk80xx: couldn't alloc irq_in_urb\n");
+		goto error;
+	}
+
+	vm_boards[idx].irq_out_urb = usb_alloc_urb(0, GFP_KERNEL);
+	if (!vm_boards[idx].irq_out_urb) {
+		err("comedi#: vmk80xx: couldn't alloc irq_out_urb\n");
+		goto error;
+	}
+
+	/* Reset the device */
+	vm_boards[idx].irq_out_buf[0] = VMK8055_CMD_RST;
+	vm_boards[idx].irq_out_buf[1] = 0x00;
+	vm_boards[idx].irq_out_buf[2] = 0x00;
+	vm_boards[idx].irq_out_buf[3] = 0x00;
+	vm_boards[idx].irq_out_buf[4] = 0x00;
+	vm_boards[idx].irq_out_buf[5] = 0x00;
+	vm_boards[idx].irq_out_buf[6] = 0x00;
+	vm_boards[idx].irq_out_buf[7] = 0x00;
+
+	usb_fill_int_urb(vm_boards[idx].irq_out_urb,
+			 udev,
+			 usb_sndintpipe(udev,
+					vm_boards[idx].irq_out_endpoint),
+			 vm_boards[idx].irq_out_buf,
+			 vm_boards[idx].irq_out_endpoint_size,
+			 vm_irq_out_callback,
+			 &vm_boards[idx],
+			 vm_boards[idx].irq_out_interval);
+
+	retval = usb_submit_urb(vm_boards[idx].irq_out_urb, GFP_KERNEL);
+	if (retval)
+		DBGCM("comedi#: vmk80xx: device reset failed (err #%d)\n",
+		      retval);
+	else
+		DBGCM("comedi#: vmk80xx: device reset success\n");
+
+
+	usb_set_intfdata(itf, &vm_boards[idx]);
+
+	/* Show some debugging messages if required */
+	DBGCM("comedi#: vmk80xx: [<-] ep addr 0x%02x size %d interval %d\n",
+	      vm_boards[idx].irq_in_endpoint,
+	      vm_boards[idx].irq_in_endpoint_size,
+	      vm_boards[idx].irq_in_interval);
+	DBGCM("comedi#: vmk80xx: [->] ep addr 0x%02x size %d interval %d\n",
+	      vm_boards[idx].irq_out_endpoint,
+	      vm_boards[idx].irq_out_endpoint_size,
+	      vm_boards[idx].irq_out_interval);
+
+	vm_boards[idx].id = idx;
+
+	/* Let the user know that the device is now attached */
+	printk("comedi#: vmk80xx: K8055 board #%d now attached\n",
+	       vm_boards[idx].id);
+
+	/* We have an attached velleman board */
+	vm_boards[idx].probed = 1;
+
+	mutex_unlock(&glb_mutex);
+
+	return retval;
+error:
+	vm_delete(&vm_boards[idx]);
+
+	mutex_unlock(&glb_mutex);
+
+	return retval;
+}
+
+static void vm_disconnect(struct usb_interface *intf)
+{
+	struct vmk80xx_usb *vm;
+
+	DBGVM("comedi#: vmk80xx: %s\n", __func__);
+
+	vm = (struct vmk80xx_usb *)usb_get_intfdata(intf);
+	if (!vm) {
+		printk("comedi#: vmk80xx: %s - vm is NULL\n", __func__);
+		return; /* -EFAULT */
+	}
+
+	mutex_lock(&glb_mutex);
+	/* Twill be needed if the driver supports more than one board */
+	down(&vm->limit_sem);
+
+	vm->probed = 0; /* we have -1 attached boards */
+	usb_set_intfdata(vm->intf, NULL);
+
+	vm_delete(vm); /* tidy up */
+
+	/* Twill be needed if the driver supports more than one board */
+	up(&vm->limit_sem);
+	mutex_unlock(&glb_mutex);
+
+	printk("comedi#: vmk80xx: Velleman board #%d now detached\n",
+	       vm->id);
+}
+
+/* ---------------------------------------------------------------------------
+ * Register/Deregister this driver with/from the usb subsystem and the comedi.
+--------------------------------------------------------------------------- */
+static struct usb_driver vm_driver = {
+#ifdef COMEDI_HAVE_USB_DRIVER_OWNER
+	.owner =	THIS_MODULE,
+#endif
+	.name =		"vmk80xx",
+	.probe =	vm_probe,
+	.disconnect =	vm_disconnect,
+	.id_table =	vm_id_table,
+};
+
+static comedi_driver driver_vm = {
+	.module =	THIS_MODULE,
+	.driver_name =	"vmk80xx",
+	.attach =	vm_attach,
+	.detach =	vm_detach,
+};
+
+static int __init vm_init(void)
+{
+	int retval, idx;
+
+	printk("vmk80xx: version " VMK80XX_MODULE_VERSION " -"
+				 " Manuel Gebele <forensixs@gmx.de>\n");
+
+	for (idx = 0; idx < VMK8055_MAX_BOARDS; idx++) {
+		memset(&vm_boards[idx], 0x00, sizeof(vm_boards[idx]));
+		init_MUTEX(&vm_boards[idx].limit_sem);
+		init_waitqueue_head(&vm_boards[idx].read_wait);
+		init_waitqueue_head(&vm_boards[idx].write_wait);
+	}
+
+	/* Register with the usb subsystem */
+	retval = usb_register(&vm_driver);
+	if (retval) {
+		err("vmk80xx: usb subsystem registration failed (err #%d)\n",
+		    retval);
+		return retval;
+	}
+
+	/* Register with the comedi core */
+	retval = comedi_driver_register(&driver_vm);
+	if (retval) {
+		err("vmk80xx: comedi core registration failed (err #%d)\n",
+		    retval);
+		usb_deregister(&vm_driver);
+	}
+
+	return retval;
+}
+
+static void __exit vm_exit(void)
+{
+	comedi_driver_unregister(&driver_vm);
+	usb_deregister(&vm_driver);
+}
+module_init(vm_init);
+module_exit(vm_exit);