comedi/drivers/usbdux.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * usbdux.c
 * Copyright (C) 2003-2014 Bernd Porr, mail@berndporr.me.uk
 */

/*
 * Driver: usbdux
 * Description: University of Stirling USB DAQ & INCITE Technology Limited
 * Devices: [ITL] USB-DUX (usbdux)
 * Author: Bernd Porr <mail@berndporr.me.uk>
 * Updated: 10 Oct 2014
 * Status: Stable
 *
 * Connection scheme for the counter at the digital port:
 * 0=/CLK0, 1=UP/DOWN0, 2=RESET0, 4=/CLK1, 5=UP/DOWN1, 6=RESET1.
 * The sampling rate of the counter is approximately 500Hz.
 *
 * Note that under USB2.0 the length of the channel list determines
 * the max sampling rate. If you sample only one channel you get 8kHz
 * sampling rate. If you sample two channels you get 4kHz and so on.
 */

/*
 * I must give credit here to Chris Baugher who
 * wrote the driver for AT-MIO-16d. I used some parts of this
 * driver. I also must give credits to David Brownell
 * who supported me with the USB development.
 *
 * Bernd Porr
 *
 *
 * Revision history:
 * 0.94: D/A output should work now with any channel list combinations
 * 0.95: .owner commented out for kernel vers below 2.4.19
 *       sanity checks in ai/ao_cmd
 * 0.96: trying to get it working with 2.6, moved all memory alloc to comedi's
 *       attach final USB IDs
 *       moved memory allocation completely to the corresponding comedi
 *       functions firmware upload is by fxload and no longer by comedi (due to
 *       enumeration)
 * 0.97: USB IDs received, adjusted table
 * 0.98: SMP, locking, memory alloc: moved all usb memory alloc
 *       to the usb subsystem and moved all comedi related memory
 *       alloc to comedi.
 *       | kernel | registration | usbdux-usb | usbdux-comedi | comedi |
 * 0.99: USB 2.0: changed protocol to isochronous transfer
 *                IRQ transfer is too buggy and too risky in 2.0
 *                for the high speed ISO transfer is now a working version
 *                available
 * 0.99b: Increased the iso transfer buffer for high sp.to 10 buffers. Some VIA
 *        chipsets miss out IRQs. Deeper buffering is needed.
 * 1.00: full USB 2.0 support for the A/D converter. Now: max 8kHz sampling
 *       rate.
 *       Firmware vers 1.00 is needed for this.
 *       Two 16 bit up/down/reset counter with a sampling rate of 1kHz
 *       And loads of cleaning up, in particular streamlining the
 *       bulk transfers.
 * 1.1:  moved EP4 transfers to EP1 to make space for a PWM output on EP4
 * 1.2:  added PWM support via EP4
 * 2.0:  PWM seems to be stable and is not interfering with the other functions
 * 2.1:  changed PWM API
 * 2.2:  added firmware kernel request to fix an udev problem
 * 2.3:  corrected a bug in bulk timeouts which were far too short
 * 2.4:  fixed a bug which causes the driver to hang when it ran out of data.
 *       Thanks to Jan-Matthias Braun and Ian to spot the bug and fix it.
 *
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/input.h>
#include <linux/fcntl.h>
#include <linux/compiler.h>

#include "../comedi_usb.h"

/* constants for firmware upload and download */
#define USBDUX_FIRMWARE		"usbdux_firmware.bin"
#define USBDUX_FIRMWARE_MAX_LEN	0x2000
#define USBDUX_FIRMWARE_CMD	0xa0
#define VENDOR_DIR_IN		0xc0
#define VENDOR_DIR_OUT		0x40
#define USBDUX_CPU_CS		0xe600

/* usbdux bulk transfer commands */
#define USBDUX_CMD_MULT_AI	0
#define USBDUX_CMD_AO		1
#define USBDUX_CMD_DIO_CFG	2
#define USBDUX_CMD_DIO_BITS	3
#define USBDUX_CMD_SINGLE_AI	4
#define USBDUX_CMD_TIMER_RD	5
#define USBDUX_CMD_TIMER_WR	6
#define USBDUX_CMD_PWM_ON	7
#define USBDUX_CMD_PWM_OFF	8

/* timeout for the USB-transfer in ms */
#define BULK_TIMEOUT		1000

/* 300Hz max frequ under PWM */
#define MIN_PWM_PERIOD		((long)(1E9 / 300))

/* Default PWM frequency */
#define PWM_DEFAULT_PERIOD	((long)(1E9 / 100))

/* Size of one A/D value */
#define SIZEADIN		((sizeof(u16)))

/*
 * Size of the input-buffer IN BYTES
 * Always multiple of 8 for 8 microframes which is needed in the highspeed mode
 */
#define SIZEINBUF		(8 * SIZEADIN)

/* 16 bytes. */
#define SIZEINSNBUF		16

/* size of one value for the D/A converter: channel and value */
#define SIZEDAOUT		((sizeof(u8) + sizeof(u16)))

/*
 * Size of the output-buffer in bytes
 * Actually only the first 4 triplets are used but for the
 * high speed mode we need to pad it to 8 (microframes).
 */
#define SIZEOUTBUF		(8 * SIZEDAOUT)

/*
 * Size of the buffer for the dux commands: just now max size is determined
 * by the analogue out + command byte + panic bytes...
 */
#define SIZEOFDUXBUFFER		(8 * SIZEDAOUT + 2)

/* Number of in-URBs which receive the data: min=2 */
#define NUMOFINBUFFERSFULL	5

/* Number of out-URBs which send the data: min=2 */
#define NUMOFOUTBUFFERSFULL	5

/* Number of in-URBs which receive the data: min=5 */
/* must have more buffers due to buggy USB ctr */
#define NUMOFINBUFFERSHIGH	10

/* Number of out-URBs which send the data: min=5 */
/* must have more buffers due to buggy USB ctr */
#define NUMOFOUTBUFFERSHIGH	10

/* number of retries to get the right dux command */
#define RETRIES			10

static const struct comedi_lrange range_usbdux_ai_range = {
	4, {
		BIP_RANGE(4.096),
		BIP_RANGE(4.096 / 2),
		UNI_RANGE(4.096),
		UNI_RANGE(4.096 / 2)
	}
};

static const struct comedi_lrange range_usbdux_ao_range = {
	2, {
		BIP_RANGE(4.096),
		UNI_RANGE(4.096)
	}
};

struct usbdux_private {
	/* actual number of in-buffers */
	int n_ai_urbs;
	/* actual number of out-buffers */
	int n_ao_urbs;
	/* ISO-transfer handling: buffers */
	struct urb **ai_urbs;
	struct urb **ao_urbs;
	/* pwm-transfer handling */
	struct urb *pwm_urb;
	/* PWM period */
	unsigned int pwm_period;
	/* PWM internal delay for the GPIF in the FX2 */
	u8 pwm_delay;
	/* size of the PWM buffer which holds the bit pattern */
	int pwm_buf_sz;
	/* input buffer for the ISO-transfer */
	__le16 *in_buf;
	/* input buffer for single insn */
	__le16 *insn_buf;

	unsigned int high_speed:1;
	unsigned int ai_cmd_running:1;
	unsigned int ao_cmd_running:1;
	unsigned int pwm_cmd_running:1;

	/* time between samples in units of the timer */
	unsigned int ai_timer;
	unsigned int ao_timer;
	/* counter between aquisitions */
	unsigned int ai_counter;
	unsigned int ao_counter;
	/* interval in frames/uframes */
	unsigned int ai_interval;
	/* commands */
	u8 *dux_commands;
	struct mutex mut;
};

static void usbdux_unlink_urbs(struct urb **urbs, int num_urbs)
{
	int i;

	for (i = 0; i < num_urbs; i++)
		usb_kill_urb(urbs[i]);
}

static void usbdux_ai_stop(struct comedi_device *dev, int do_unlink)
{
	struct usbdux_private *devpriv = dev->private;

	if (do_unlink && devpriv->ai_urbs)
		usbdux_unlink_urbs(devpriv->ai_urbs, devpriv->n_ai_urbs);

	devpriv->ai_cmd_running = 0;
}

static int usbdux_ai_cancel(struct comedi_device *dev,
			    struct comedi_subdevice *s)
{
	struct usbdux_private *devpriv = dev->private;

	/* prevent other CPUs from submitting new commands just now */
	mutex_lock(&devpriv->mut);
	/* unlink only if the urb really has been submitted */
	usbdux_ai_stop(dev, devpriv->ai_cmd_running);
	mutex_unlock(&devpriv->mut);

	return 0;
}

static void usbduxsub_ai_handle_urb(struct comedi_device *dev,
				    struct comedi_subdevice *s,
				    struct urb *urb)
{
	struct usbdux_private *devpriv = dev->private;
	struct comedi_async *async = s->async;
	struct comedi_cmd *cmd = &async->cmd;
	int ret;
	int i;

	devpriv->ai_counter--;
	if (devpriv->ai_counter == 0) {
		devpriv->ai_counter = devpriv->ai_timer;

		/* get the data from the USB bus and hand it over to comedi */
		for (i = 0; i < cmd->chanlist_len; i++) {
			unsigned int range = CR_RANGE(cmd->chanlist[i]);
			u16 val = le16_to_cpu(devpriv->in_buf[i]);

			/* bipolar data is two's-complement */
			if (comedi_range_is_bipolar(s, range))
				val = comedi_offset_munge(s, val);

			/* transfer data */
			if (!comedi_buf_write_samples(s, &val, 1))
				return;
		}

		if (cmd->stop_src == TRIG_COUNT &&
		    async->scans_done >= cmd->stop_arg)
			async->events |= COMEDI_CB_EOA;
	}

	/* if command is still running, resubmit urb */
	if (!(async->events & COMEDI_CB_CANCEL_MASK)) {
		urb->dev = comedi_to_usb_dev(dev);
		ret = usb_submit_urb(urb, GFP_ATOMIC);
		if (ret < 0) {
			dev_err(dev->class_dev,
				"urb resubmit failed in int-context! err=%d\n",
				ret);
			if (ret == -EL2NSYNC)
				dev_err(dev->class_dev,
					"buggy USB host controller or bug in IRQ handler!\n");
			async->events |= COMEDI_CB_ERROR;
		}
	}
}

static void usbduxsub_ai_isoc_irq(struct urb *urb)
{
	struct comedi_device *dev = urb->context;
	struct comedi_subdevice *s = dev->read_subdev;
	struct comedi_async *async = s->async;
	struct usbdux_private *devpriv = dev->private;

	/* exit if not running a command, do not resubmit urb */
	if (!devpriv->ai_cmd_running)
		return;

	switch (urb->status) {
	case 0:
		/* copy the result in the transfer buffer */
		memcpy(devpriv->in_buf, urb->transfer_buffer, SIZEINBUF);
		usbduxsub_ai_handle_urb(dev, s, urb);
		break;

	case -EILSEQ:
		/*
		 * error in the ISOchronous data
		 * we don't copy the data into the transfer buffer
		 * and recycle the last data byte
		 */
		dev_dbg(dev->class_dev, "CRC error in ISO IN stream\n");
		usbduxsub_ai_handle_urb(dev, s, urb);
		break;

	case -ECONNRESET:
	case -ENOENT:
	case -ESHUTDOWN:
	case -ECONNABORTED:
		/* after an unlink command, unplug, ... etc */
		async->events |= COMEDI_CB_ERROR;
		break;

	default:
		/* a real error */
		dev_err(dev->class_dev,
			"Non-zero urb status received in ai intr context: %d\n",
			urb->status);
		async->events |= COMEDI_CB_ERROR;
		break;
	}

	/*
	 * comedi_handle_events() cannot be used in this driver. The (*cancel)
	 * operation would unlink the urb.
	 */
	if (async->events & COMEDI_CB_CANCEL_MASK)
		usbdux_ai_stop(dev, 0);

	comedi_event(dev, s);
}

static void usbdux_ao_stop(struct comedi_device *dev, int do_unlink)
{
	struct usbdux_private *devpriv = dev->private;

	if (do_unlink && devpriv->ao_urbs)
		usbdux_unlink_urbs(devpriv->ao_urbs, devpriv->n_ao_urbs);

	devpriv->ao_cmd_running = 0;
}

static int usbdux_ao_cancel(struct comedi_device *dev,
			    struct comedi_subdevice *s)
{
	struct usbdux_private *devpriv = dev->private;

	/* prevent other CPUs from submitting a command just now */
	mutex_lock(&devpriv->mut);
	/* unlink only if it is really running */
	usbdux_ao_stop(dev, devpriv->ao_cmd_running);
	mutex_unlock(&devpriv->mut);

	return 0;
}

static void usbduxsub_ao_handle_urb(struct comedi_device *dev,
				    struct comedi_subdevice *s,
				    struct urb *urb)
{
	struct usbdux_private *devpriv = dev->private;
	struct comedi_async *async = s->async;
	struct comedi_cmd *cmd = &async->cmd;
	u8 *datap;
	int ret;
	int i;

	devpriv->ao_counter--;
	if (devpriv->ao_counter == 0) {
		devpriv->ao_counter = devpriv->ao_timer;

		if (cmd->stop_src == TRIG_COUNT &&
		    async->scans_done >= cmd->stop_arg) {
			async->events |= COMEDI_CB_EOA;
			return;
		}

		/* transmit data to the USB bus */
		datap = urb->transfer_buffer;
		*datap++ = cmd->chanlist_len;
		for (i = 0; i < cmd->chanlist_len; i++) {
			unsigned int chan = CR_CHAN(cmd->chanlist[i]);
			unsigned short val;

			if (!comedi_buf_read_samples(s, &val, 1)) {
				dev_err(dev->class_dev, "buffer underflow\n");
				async->events |= COMEDI_CB_OVERFLOW;
				return;
			}

			/* pointer to the DA */
			*datap++ = val & 0xff;
			*datap++ = (val >> 8) & 0xff;
			*datap++ = chan << 6;
			s->readback[chan] = val;
		}
	}

	/* if command is still running, resubmit urb for BULK transfer */
	if (!(async->events & COMEDI_CB_CANCEL_MASK)) {
		urb->transfer_buffer_length = SIZEOUTBUF;
		urb->dev = comedi_to_usb_dev(dev);
		urb->status = 0;
		if (devpriv->high_speed)
			urb->interval = 8;	/* uframes */
		else
			urb->interval = 1;	/* frames */
		urb->number_of_packets = 1;
		urb->iso_frame_desc[0].offset = 0;
		urb->iso_frame_desc[0].length = SIZEOUTBUF;
		urb->iso_frame_desc[0].status = 0;
		ret = usb_submit_urb(urb, GFP_ATOMIC);
		if (ret < 0) {
			dev_err(dev->class_dev,
				"ao urb resubm failed in int-cont. ret=%d",
				ret);
			if (ret == -EL2NSYNC)
				dev_err(dev->class_dev,
					"buggy USB host controller or bug in IRQ handling!\n");
			async->events |= COMEDI_CB_ERROR;
		}
	}
}

static void usbduxsub_ao_isoc_irq(struct urb *urb)
{
	struct comedi_device *dev = urb->context;
	struct comedi_subdevice *s = dev->write_subdev;
	struct comedi_async *async = s->async;
	struct usbdux_private *devpriv = dev->private;

	/* exit if not running a command, do not resubmit urb */
	if (!devpriv->ao_cmd_running)
		return;

	switch (urb->status) {
	case 0:
		usbduxsub_ao_handle_urb(dev, s, urb);
		break;

	case -ECONNRESET:
	case -ENOENT:
	case -ESHUTDOWN:
	case -ECONNABORTED:
		/* after an unlink command, unplug, ... etc */
		async->events |= COMEDI_CB_ERROR;
		break;

	default:
		/* a real error */
		dev_err(dev->class_dev,
			"Non-zero urb status received in ao intr context: %d\n",
			urb->status);
		async->events |= COMEDI_CB_ERROR;
		break;
	}

	/*
	 * comedi_handle_events() cannot be used in this driver. The (*cancel)
	 * operation would unlink the urb.
	 */
	if (async->events & COMEDI_CB_CANCEL_MASK)
		usbdux_ao_stop(dev, 0);

	comedi_event(dev, s);
}

static int usbdux_submit_urbs(struct comedi_device *dev,
			      struct urb **urbs, int num_urbs,
			      int input_urb)
{
	struct usb_device *usb = comedi_to_usb_dev(dev);
	struct usbdux_private *devpriv = dev->private;
	struct urb *urb;
	int ret;
	int i;

	/* Submit all URBs and start the transfer on the bus */
	for (i = 0; i < num_urbs; i++) {
		urb = urbs[i];

		/* in case of a resubmission after an unlink... */
		if (input_urb)
			urb->interval = devpriv->ai_interval;
		urb->context = dev;
		urb->dev = usb;
		urb->status = 0;
		urb->transfer_flags = URB_ISO_ASAP;

		ret = usb_submit_urb(urb, GFP_ATOMIC);
		if (ret)
			return ret;
	}
	return 0;
}

static int usbdux_ai_cmdtest(struct comedi_device *dev,
			     struct comedi_subdevice *s, struct comedi_cmd *cmd)
{
	struct usbdux_private *devpriv = dev->private;
	int err = 0;

	/* Step 1 : check if triggers are trivially valid */

	err |= comedi_check_trigger_src(&cmd->start_src, TRIG_NOW | TRIG_INT);
	err |= comedi_check_trigger_src(&cmd->scan_begin_src, TRIG_TIMER);
	err |= comedi_check_trigger_src(&cmd->convert_src, TRIG_NOW);
	err |= comedi_check_trigger_src(&cmd->scan_end_src, TRIG_COUNT);
	err |= comedi_check_trigger_src(&cmd->stop_src, TRIG_COUNT | TRIG_NONE);

	if (err)
		return 1;

	/* Step 2a : make sure trigger sources are unique */

	err |= comedi_check_trigger_is_unique(cmd->start_src);
	err |= comedi_check_trigger_is_unique(cmd->stop_src);

	/* Step 2b : and mutually compatible */

	if (err)
		return 2;

	/* Step 3: check if arguments are trivially valid */

	err |= comedi_check_trigger_arg_is(&cmd->start_arg, 0);

	if (cmd->scan_begin_src == TRIG_FOLLOW)	/* internal trigger */
		err |= comedi_check_trigger_arg_is(&cmd->scan_begin_arg, 0);

	if (cmd->scan_begin_src == TRIG_TIMER) {
		/* full speed does 1kHz scans every USB frame */
		unsigned int arg = 1000000;
		unsigned int min_arg = arg;

		if (devpriv->high_speed) {
			/*
			 * In high speed mode microframes are possible.
			 * However, during one microframe we can roughly
			 * sample one channel. Thus, the more channels
			 * are in the channel list the more time we need.
			 */
			int i = 1;

			/* find a power of 2 for the number of channels */
			while (i < cmd->chanlist_len)
				i = i * 2;

			arg /= 8;
			min_arg = arg * i;
		}
		err |= comedi_check_trigger_arg_min(&cmd->scan_begin_arg,
						    min_arg);
		/* calc the real sampling rate with the rounding errors */
		arg = (cmd->scan_begin_arg / arg) * arg;
		err |= comedi_check_trigger_arg_is(&cmd->scan_begin_arg, arg);
	}

	err |= comedi_check_trigger_arg_is(&cmd->scan_end_arg,
					   cmd->chanlist_len);

	if (cmd->stop_src == TRIG_COUNT)
		err |= comedi_check_trigger_arg_min(&cmd->stop_arg, 1);
	else	/* TRIG_NONE */
		err |= comedi_check_trigger_arg_is(&cmd->stop_arg, 0);

	if (err)
		return 3;

	return 0;
}

/*
 * creates the ADC command for the MAX1271
 * range is the range value from comedi
 */
static u8 create_adc_command(unsigned int chan, unsigned int range)
{
	u8 p = (range <= 1);
	u8 r = ((range % 2) == 0);

	return (chan << 4) | ((p == 1) << 2) | ((r == 1) << 3);
}

static int send_dux_commands(struct comedi_device *dev, unsigned int cmd_type)
{
	struct usb_device *usb = comedi_to_usb_dev(dev);
	struct usbdux_private *devpriv = dev->private;
	int nsent;

	devpriv->dux_commands[0] = cmd_type;

	return usb_bulk_msg(usb, usb_sndbulkpipe(usb, 1),
			    devpriv->dux_commands, SIZEOFDUXBUFFER,
			    &nsent, BULK_TIMEOUT);
}

static int receive_dux_commands(struct comedi_device *dev, unsigned int command)
{
	struct usb_device *usb = comedi_to_usb_dev(dev);
	struct usbdux_private *devpriv = dev->private;
	int ret;
	int nrec;
	int i;

	for (i = 0; i < RETRIES; i++) {
		ret = usb_bulk_msg(usb, usb_rcvbulkpipe(usb, 8),
				   devpriv->insn_buf, SIZEINSNBUF,
				   &nrec, BULK_TIMEOUT);
		if (ret < 0)
			return ret;
		if (le16_to_cpu(devpriv->insn_buf[0]) == command)
			return ret;
	}
	/* command not received */
	return -EFAULT;
}

static int usbdux_ai_inttrig(struct comedi_device *dev,
			     struct comedi_subdevice *s,
			     unsigned int trig_num)
{
	struct usbdux_private *devpriv = dev->private;
	struct comedi_cmd *cmd = &s->async->cmd;
	int ret;

	if (trig_num != cmd->start_arg)
		return -EINVAL;

	mutex_lock(&devpriv->mut);

	if (!devpriv->ai_cmd_running) {
		devpriv->ai_cmd_running = 1;
		ret = usbdux_submit_urbs(dev, devpriv->ai_urbs,
					 devpriv->n_ai_urbs, 1);
		if (ret < 0) {
			devpriv->ai_cmd_running = 0;
			goto ai_trig_exit;
		}
		s->async->inttrig = NULL;
	} else {
		ret = -EBUSY;
	}

ai_trig_exit:
	mutex_unlock(&devpriv->mut);
	return ret;
}

static int usbdux_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
{
	struct usbdux_private *devpriv = dev->private;
	struct comedi_cmd *cmd = &s->async->cmd;
	int len = cmd->chanlist_len;
	int ret = -EBUSY;
	int i;

	/* block other CPUs from starting an ai_cmd */
	mutex_lock(&devpriv->mut);

	if (devpriv->ai_cmd_running)
		goto ai_cmd_exit;

	devpriv->dux_commands[1] = len;
	for (i = 0; i < len; ++i) {
		unsigned int chan = CR_CHAN(cmd->chanlist[i]);
		unsigned int range = CR_RANGE(cmd->chanlist[i]);

		devpriv->dux_commands[i + 2] = create_adc_command(chan, range);
	}

	ret = send_dux_commands(dev, USBDUX_CMD_MULT_AI);
	if (ret < 0)
		goto ai_cmd_exit;

	if (devpriv->high_speed) {
		/*
		 * every channel gets a time window of 125us. Thus, if we
		 * sample all 8 channels we need 1ms. If we sample only one
		 * channel we need only 125us
		 */
		devpriv->ai_interval = 1;
		/* find a power of 2 for the interval */
		while (devpriv->ai_interval < len)
			devpriv->ai_interval *= 2;

		devpriv->ai_timer = cmd->scan_begin_arg /
				    (125000 * devpriv->ai_interval);
	} else {
		/* interval always 1ms */
		devpriv->ai_interval = 1;
		devpriv->ai_timer = cmd->scan_begin_arg / 1000000;
	}
	if (devpriv->ai_timer < 1) {
		ret = -EINVAL;
		goto ai_cmd_exit;
	}

	devpriv->ai_counter = devpriv->ai_timer;

	if (cmd->start_src == TRIG_NOW) {
		/* enable this acquisition operation */
		devpriv->ai_cmd_running = 1;
		ret = usbdux_submit_urbs(dev, devpriv->ai_urbs,
					 devpriv->n_ai_urbs, 1);
		if (ret < 0) {
			devpriv->ai_cmd_running = 0;
			/* fixme: unlink here?? */
			goto ai_cmd_exit;
		}
		s->async->inttrig = NULL;
	} else {
		/* TRIG_INT */
		/* don't enable the acquision operation */
		/* wait for an internal signal */
		s->async->inttrig = usbdux_ai_inttrig;
	}

ai_cmd_exit:
	mutex_unlock(&devpriv->mut);

	return ret;
}

/* Mode 0 is used to get a single conversion on demand */
static int usbdux_ai_insn_read(struct comedi_device *dev,
			       struct comedi_subdevice *s,
			       struct comedi_insn *insn,
			       unsigned int *data)
{
	struct usbdux_private *devpriv = dev->private;
	unsigned int chan = CR_CHAN(insn->chanspec);
	unsigned int range = CR_RANGE(insn->chanspec);
	unsigned int val;
	int ret = -EBUSY;
	int i;

	mutex_lock(&devpriv->mut);

	if (devpriv->ai_cmd_running)
		goto ai_read_exit;

	/* set command for the first channel */
	devpriv->dux_commands[1] = create_adc_command(chan, range);

	/* adc commands */
	ret = send_dux_commands(dev, USBDUX_CMD_SINGLE_AI);
	if (ret < 0)
		goto ai_read_exit;

	for (i = 0; i < insn->n; i++) {
		ret = receive_dux_commands(dev, USBDUX_CMD_SINGLE_AI);
		if (ret < 0)
			goto ai_read_exit;

		val = le16_to_cpu(devpriv->insn_buf[1]);

		/* bipolar data is two's-complement */
		if (comedi_range_is_bipolar(s, range))
			val = comedi_offset_munge(s, val);

		data[i] = val;
	}

ai_read_exit:
	mutex_unlock(&devpriv->mut);

	return ret ? ret : insn->n;
}

static int usbdux_ao_insn_read(struct comedi_device *dev,
			       struct comedi_subdevice *s,
			       struct comedi_insn *insn,
			       unsigned int *data)
{
	struct usbdux_private *devpriv = dev->private;
	int ret;

	mutex_lock(&devpriv->mut);
	ret = comedi_readback_insn_read(dev, s, insn, data);
	mutex_unlock(&devpriv->mut);

	return ret;
}

static int usbdux_ao_insn_write(struct comedi_device *dev,
				struct comedi_subdevice *s,
				struct comedi_insn *insn,
				unsigned int *data)
{
	struct usbdux_private *devpriv = dev->private;
	unsigned int chan = CR_CHAN(insn->chanspec);
	__le16 *p = (__le16 *)&devpriv->dux_commands[2];
	int ret = -EBUSY;
	int i;

	mutex_lock(&devpriv->mut);

	if (devpriv->ao_cmd_running)
		goto ao_write_exit;

	/* number of channels: 1 */
	devpriv->dux_commands[1] = 1;
	/* channel number */
	devpriv->dux_commands[4] = chan << 6;

	for (i = 0; i < insn->n; i++) {
		unsigned int val = data[i];

		/* one 16 bit value */
		*p = cpu_to_le16(val);

		ret = send_dux_commands(dev, USBDUX_CMD_AO);
		if (ret < 0)
			goto ao_write_exit;

		s->readback[chan] = val;
	}

ao_write_exit:
	mutex_unlock(&devpriv->mut);

	return ret ? ret : insn->n;
}

static int usbdux_ao_inttrig(struct comedi_device *dev,
			     struct comedi_subdevice *s,
			     unsigned int trig_num)
{
	struct usbdux_private *devpriv = dev->private;
	struct comedi_cmd *cmd = &s->async->cmd;
	int ret;

	if (trig_num != cmd->start_arg)
		return -EINVAL;

	mutex_lock(&devpriv->mut);

	if (!devpriv->ao_cmd_running) {
		devpriv->ao_cmd_running = 1;
		ret = usbdux_submit_urbs(dev, devpriv->ao_urbs,
					 devpriv->n_ao_urbs, 0);
		if (ret < 0) {
			devpriv->ao_cmd_running = 0;
			goto ao_trig_exit;
		}
		s->async->inttrig = NULL;
	} else {
		ret = -EBUSY;
	}

ao_trig_exit:
	mutex_unlock(&devpriv->mut);
	return ret;
}

static int usbdux_ao_cmdtest(struct comedi_device *dev,
			     struct comedi_subdevice *s, struct comedi_cmd *cmd)
{
	int err = 0;
	unsigned int flags;

	/* Step 1 : check if triggers are trivially valid */

	err |= comedi_check_trigger_src(&cmd->start_src, TRIG_NOW | TRIG_INT);

	if (0) {		/* (devpriv->high_speed) */
		/* the sampling rate is set by the coversion rate */
		flags = TRIG_FOLLOW;
	} else {
		/* start a new scan (output at once) with a timer */
		flags = TRIG_TIMER;
	}
	err |= comedi_check_trigger_src(&cmd->scan_begin_src, flags);

	if (0) {		/* (devpriv->high_speed) */
		/*
		 * in usb-2.0 only one conversion it transmitted
		 * but with 8kHz/n
		 */
		flags = TRIG_TIMER;
	} else {
		/*
		 * all conversion events happen simultaneously with
		 * a rate of 1kHz/n
		 */
		flags = TRIG_NOW;
	}
	err |= comedi_check_trigger_src(&cmd->convert_src, flags);

	err |= comedi_check_trigger_src(&cmd->scan_end_src, TRIG_COUNT);
	err |= comedi_check_trigger_src(&cmd->stop_src, TRIG_COUNT | TRIG_NONE);

	if (err)
		return 1;

	/* Step 2a : make sure trigger sources are unique */

	err |= comedi_check_trigger_is_unique(cmd->start_src);
	err |= comedi_check_trigger_is_unique(cmd->stop_src);

	/* Step 2b : and mutually compatible */

	if (err)
		return 2;

	/* Step 3: check if arguments are trivially valid */

	err |= comedi_check_trigger_arg_is(&cmd->start_arg, 0);

	if (cmd->scan_begin_src == TRIG_FOLLOW)	/* internal trigger */
		err |= comedi_check_trigger_arg_is(&cmd->scan_begin_arg, 0);

	if (cmd->scan_begin_src == TRIG_TIMER) {
		err |= comedi_check_trigger_arg_min(&cmd->scan_begin_arg,
						    1000000);
	}

	/* not used now, is for later use */
	if (cmd->convert_src == TRIG_TIMER)
		err |= comedi_check_trigger_arg_min(&cmd->convert_arg, 125000);

	err |= comedi_check_trigger_arg_is(&cmd->scan_end_arg,
					   cmd->chanlist_len);

	if (cmd->stop_src == TRIG_COUNT)
		err |= comedi_check_trigger_arg_min(&cmd->stop_arg, 1);
	else	/* TRIG_NONE */
		err |= comedi_check_trigger_arg_is(&cmd->stop_arg, 0);

	if (err)
		return 3;

	return 0;
}

static int usbdux_ao_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
{
	struct usbdux_private *devpriv = dev->private;
	struct comedi_cmd *cmd = &s->async->cmd;
	int ret = -EBUSY;

	mutex_lock(&devpriv->mut);

	if (devpriv->ao_cmd_running)
		goto ao_cmd_exit;

	/* we count in steps of 1ms (125us) */
	/* 125us mode not used yet */
	if (0) {		/* (devpriv->high_speed) */
		/* 125us */
		/* timing of the conversion itself: every 125 us */
		devpriv->ao_timer = cmd->convert_arg / 125000;
	} else {
		/* 1ms */
		/* timing of the scan: we get all channels at once */
		devpriv->ao_timer = cmd->scan_begin_arg / 1000000;
		if (devpriv->ao_timer < 1) {
			ret = -EINVAL;
			goto ao_cmd_exit;
		}
	}

	devpriv->ao_counter = devpriv->ao_timer;

	if (cmd->start_src == TRIG_NOW) {
		/* enable this acquisition operation */
		devpriv->ao_cmd_running = 1;
		ret = usbdux_submit_urbs(dev, devpriv->ao_urbs,
					 devpriv->n_ao_urbs, 0);
		if (ret < 0) {
			devpriv->ao_cmd_running = 0;
			/* fixme: unlink here?? */
			goto ao_cmd_exit;
		}
		s->async->inttrig = NULL;
	} else {
		/* TRIG_INT */
		/* submit the urbs later */
		/* wait for an internal signal */
		s->async->inttrig = usbdux_ao_inttrig;
	}

ao_cmd_exit:
	mutex_unlock(&devpriv->mut);

	return ret;
}

static int usbdux_dio_insn_config(struct comedi_device *dev,
				  struct comedi_subdevice *s,
				  struct comedi_insn *insn,
				  unsigned int *data)
{
	int ret;

	ret = comedi_dio_insn_config(dev, s, insn, data, 0);
	if (ret)
		return ret;

	/*
	 * We don't tell the firmware here as it would take 8 frames
	 * to submit the information. We do it in the insn_bits.
	 */
	return insn->n;
}

static int usbdux_dio_insn_bits(struct comedi_device *dev,
				struct comedi_subdevice *s,
				struct comedi_insn *insn,
				unsigned int *data)
{
	struct usbdux_private *devpriv = dev->private;
	int ret;

	mutex_lock(&devpriv->mut);

	comedi_dio_update_state(s, data);

	/* Always update the hardware. See the (*insn_config). */
	devpriv->dux_commands[1] = s->io_bits;
	devpriv->dux_commands[2] = s->state;

	/*
	 * This command also tells the firmware to return
	 * the digital input lines.
	 */
	ret = send_dux_commands(dev, USBDUX_CMD_DIO_BITS);
	if (ret < 0)
		goto dio_exit;
	ret = receive_dux_commands(dev, USBDUX_CMD_DIO_BITS);
	if (ret < 0)
		goto dio_exit;

	data[1] = le16_to_cpu(devpriv->insn_buf[1]);

dio_exit:
	mutex_unlock(&devpriv->mut);

	return ret ? ret : insn->n;
}

static int usbdux_counter_read(struct comedi_device *dev,
			       struct comedi_subdevice *s,
			       struct comedi_insn *insn,
			       unsigned int *data)
{
	struct usbdux_private *devpriv = dev->private;
	unsigned int chan = CR_CHAN(insn->chanspec);
	int ret = 0;
	int i;

	mutex_lock(&devpriv->mut);

	for (i = 0; i < insn->n; i++) {
		ret = send_dux_commands(dev, USBDUX_CMD_TIMER_RD);
		if (ret < 0)
			goto counter_read_exit;
		ret = receive_dux_commands(dev, USBDUX_CMD_TIMER_RD);
		if (ret < 0)
			goto counter_read_exit;

		data[i] = le16_to_cpu(devpriv->insn_buf[chan + 1]);
	}

counter_read_exit:
	mutex_unlock(&devpriv->mut);

	return ret ? ret : insn->n;
}

static int usbdux_counter_write(struct comedi_device *dev,
				struct comedi_subdevice *s,
				struct comedi_insn *insn,
				unsigned int *data)
{
	struct usbdux_private *devpriv = dev->private;
	unsigned int chan = CR_CHAN(insn->chanspec);
	__le16 *p = (__le16 *)&devpriv->dux_commands[2];
	int ret = 0;
	int i;

	mutex_lock(&devpriv->mut);

	devpriv->dux_commands[1] = chan;

	for (i = 0; i < insn->n; i++) {
		*p = cpu_to_le16(data[i]);

		ret = send_dux_commands(dev, USBDUX_CMD_TIMER_WR);
		if (ret < 0)
			break;
	}

	mutex_unlock(&devpriv->mut);

	return ret ? ret : insn->n;
}

static int usbdux_counter_config(struct comedi_device *dev,
				 struct comedi_subdevice *s,
				 struct comedi_insn *insn, unsigned int *data)
{
	/* nothing to do so far */
	return 2;
}

static void usbduxsub_unlink_pwm_urbs(struct comedi_device *dev)
{
	struct usbdux_private *devpriv = dev->private;

	usb_kill_urb(devpriv->pwm_urb);
}

static void usbdux_pwm_stop(struct comedi_device *dev, int do_unlink)
{
	struct usbdux_private *devpriv = dev->private;

	if (do_unlink)
		usbduxsub_unlink_pwm_urbs(dev);

	devpriv->pwm_cmd_running = 0;
}

static int usbdux_pwm_cancel(struct comedi_device *dev,
			     struct comedi_subdevice *s)
{
	struct usbdux_private *devpriv = dev->private;
	int ret;

	mutex_lock(&devpriv->mut);
	/* unlink only if it is really running */
	usbdux_pwm_stop(dev, devpriv->pwm_cmd_running);
	ret = send_dux_commands(dev, USBDUX_CMD_PWM_OFF);
	mutex_unlock(&devpriv->mut);

	return ret;
}

static void usbduxsub_pwm_irq(struct urb *urb)
{
	struct comedi_device *dev = urb->context;
	struct usbdux_private *devpriv = dev->private;
	int ret;

	switch (urb->status) {
	case 0:
		/* success */
		break;

	case -ECONNRESET:
	case -ENOENT:
	case -ESHUTDOWN:
	case -ECONNABORTED:
		/*
		 * after an unlink command, unplug, ... etc
		 * no unlink needed here. Already shutting down.
		 */
		if (devpriv->pwm_cmd_running)
			usbdux_pwm_stop(dev, 0);

		return;

	default:
		/* a real error */
		if (devpriv->pwm_cmd_running) {
			dev_err(dev->class_dev,
				"Non-zero urb status received in pwm intr context: %d\n",
				urb->status);
			usbdux_pwm_stop(dev, 0);
		}
		return;
	}

	/* are we actually running? */
	if (!devpriv->pwm_cmd_running)
		return;

	urb->transfer_buffer_length = devpriv->pwm_buf_sz;
	urb->dev = comedi_to_usb_dev(dev);
	urb->status = 0;
	if (devpriv->pwm_cmd_running) {
		ret = usb_submit_urb(urb, GFP_ATOMIC);
		if (ret < 0) {
			dev_err(dev->class_dev,
				"pwm urb resubm failed in int-cont. ret=%d",
				ret);
			if (ret == -EL2NSYNC)
				dev_err(dev->class_dev,
					"buggy USB host controller or bug in IRQ handling!\n");

			/* don't do an unlink here */
			usbdux_pwm_stop(dev, 0);
		}
	}
}

static int usbduxsub_submit_pwm_urbs(struct comedi_device *dev)
{
	struct usb_device *usb = comedi_to_usb_dev(dev);
	struct usbdux_private *devpriv = dev->private;
	struct urb *urb = devpriv->pwm_urb;

	/* in case of a resubmission after an unlink... */
	usb_fill_bulk_urb(urb, usb, usb_sndbulkpipe(usb, 4),
			  urb->transfer_buffer,
			  devpriv->pwm_buf_sz,
			  usbduxsub_pwm_irq,
			  dev);

	return usb_submit_urb(urb, GFP_ATOMIC);
}

static int usbdux_pwm_period(struct comedi_device *dev,
			     struct comedi_subdevice *s,
			     unsigned int period)
{
	struct usbdux_private *devpriv = dev->private;
	int fx2delay;

	if (period < MIN_PWM_PERIOD)
		return -EAGAIN;

	fx2delay = (period / (6 * 512 * 1000 / 33)) - 6;
	if (fx2delay > 255)
		return -EAGAIN;

	devpriv->pwm_delay = fx2delay;
	devpriv->pwm_period = period;

	return 0;
}

static int usbdux_pwm_start(struct comedi_device *dev,
			    struct comedi_subdevice *s)
{
	struct usbdux_private *devpriv = dev->private;
	int ret = 0;

	mutex_lock(&devpriv->mut);

	if (devpriv->pwm_cmd_running)
		goto pwm_start_exit;

	devpriv->dux_commands[1] = devpriv->pwm_delay;
	ret = send_dux_commands(dev, USBDUX_CMD_PWM_ON);
	if (ret < 0)
		goto pwm_start_exit;

	/* initialise the buffer */
	memset(devpriv->pwm_urb->transfer_buffer, 0, devpriv->pwm_buf_sz);

	devpriv->pwm_cmd_running = 1;
	ret = usbduxsub_submit_pwm_urbs(dev);
	if (ret < 0)
		devpriv->pwm_cmd_running = 0;

pwm_start_exit:
	mutex_unlock(&devpriv->mut);

	return ret;
}

static void usbdux_pwm_pattern(struct comedi_device *dev,
			       struct comedi_subdevice *s,
			       unsigned int chan,
			       unsigned int value,
			       unsigned int sign)
{
	struct usbdux_private *devpriv = dev->private;
	char pwm_mask = (1 << chan);	/* DIO bit for the PWM data */
	char sgn_mask = (16 << chan);	/* DIO bit for the sign */
	char *buf = (char *)(devpriv->pwm_urb->transfer_buffer);
	int szbuf = devpriv->pwm_buf_sz;
	int i;

	for (i = 0; i < szbuf; i++) {
		char c = *buf;

		c &= ~pwm_mask;
		if (i < value)
			c |= pwm_mask;
		if (!sign)
			c &= ~sgn_mask;
		else
			c |= sgn_mask;
		*buf++ = c;
	}
}

static int usbdux_pwm_write(struct comedi_device *dev,
			    struct comedi_subdevice *s,
			    struct comedi_insn *insn,
			    unsigned int *data)
{
	unsigned int chan = CR_CHAN(insn->chanspec);

	/*
	 * It doesn't make sense to support more than one value here
	 * because it would just overwrite the PWM buffer.
	 */
	if (insn->n != 1)
		return -EINVAL;

	/*
	 * The sign is set via a special INSN only, this gives us 8 bits
	 * for normal operation, sign is 0 by default.
	 */
	usbdux_pwm_pattern(dev, s, chan, data[0], 0);

	return insn->n;
}

static int usbdux_pwm_config(struct comedi_device *dev,
			     struct comedi_subdevice *s,
			     struct comedi_insn *insn,
			     unsigned int *data)
{
	struct usbdux_private *devpriv = dev->private;
	unsigned int chan = CR_CHAN(insn->chanspec);

	switch (data[0]) {
	case INSN_CONFIG_ARM:
		/*
		 * if not zero the PWM is limited to a certain time which is
		 * not supported here
		 */
		if (data[1] != 0)
			return -EINVAL;
		return usbdux_pwm_start(dev, s);
	case INSN_CONFIG_DISARM:
		return usbdux_pwm_cancel(dev, s);
	case INSN_CONFIG_GET_PWM_STATUS:
		data[1] = devpriv->pwm_cmd_running;
		return 0;
	case INSN_CONFIG_PWM_SET_PERIOD:
		return usbdux_pwm_period(dev, s, data[1]);
	case INSN_CONFIG_PWM_GET_PERIOD:
		data[1] = devpriv->pwm_period;
		return 0;
	case INSN_CONFIG_PWM_SET_H_BRIDGE:
		/*
		 * data[1] = value
		 * data[2] = sign (for a relay)
		 */
		usbdux_pwm_pattern(dev, s, chan, data[1], (data[2] != 0));
		return 0;
	case INSN_CONFIG_PWM_GET_H_BRIDGE:
		/* values are not kept in this driver, nothing to return here */
		return -EINVAL;
	}
	return -EINVAL;
}

static int usbdux_firmware_upload(struct comedi_device *dev,
				  const u8 *data, size_t size,
				  unsigned long context)
{
	struct usb_device *usb = comedi_to_usb_dev(dev);
	u8 *buf;
	u8 *tmp;
	int ret;

	if (!data)
		return 0;

	if (size > USBDUX_FIRMWARE_MAX_LEN) {
		dev_err(dev->class_dev,
			"usbdux firmware binary it too large for FX2.\n");
		return -ENOMEM;
	}

	/* we generate a local buffer for the firmware */
	buf = kmemdup(data, size, GFP_KERNEL);
	if (!buf)
		return -ENOMEM;

	/* we need a malloc'ed buffer for usb_control_msg() */
	tmp = kmalloc(1, GFP_KERNEL);
	if (!tmp) {
		kfree(buf);
		return -ENOMEM;
	}

	/* stop the current firmware on the device */
	*tmp = 1;	/* 7f92 to one */
	ret = usb_control_msg(usb, usb_sndctrlpipe(usb, 0),
			      USBDUX_FIRMWARE_CMD,
			      VENDOR_DIR_OUT,
			      USBDUX_CPU_CS, 0x0000,
			      tmp, 1,
			      BULK_TIMEOUT);
	if (ret < 0) {
		dev_err(dev->class_dev, "can not stop firmware\n");
		goto done;
	}

	/* upload the new firmware to the device */
	ret = usb_control_msg(usb, usb_sndctrlpipe(usb, 0),
			      USBDUX_FIRMWARE_CMD,
			      VENDOR_DIR_OUT,
			      0, 0x0000,
			      buf, size,
			      BULK_TIMEOUT);
	if (ret < 0) {
		dev_err(dev->class_dev, "firmware upload failed\n");
		goto done;
	}

	/* start the new firmware on the device */
	*tmp = 0;	/* 7f92 to zero */
	ret = usb_control_msg(usb, usb_sndctrlpipe(usb, 0),
			      USBDUX_FIRMWARE_CMD,
			      VENDOR_DIR_OUT,
			      USBDUX_CPU_CS, 0x0000,
			      tmp, 1,
			      BULK_TIMEOUT);
	if (ret < 0)
		dev_err(dev->class_dev, "can not start firmware\n");

done:
	kfree(tmp);
	kfree(buf);
	return ret;
}

static int usbdux_alloc_usb_buffers(struct comedi_device *dev)
{
	struct usb_device *usb = comedi_to_usb_dev(dev);
	struct usbdux_private *devpriv = dev->private;
	struct urb *urb;
	int i;

	devpriv->dux_commands = kzalloc(SIZEOFDUXBUFFER, GFP_KERNEL);
	devpriv->in_buf = kzalloc(SIZEINBUF, GFP_KERNEL);
	devpriv->insn_buf = kzalloc(SIZEINSNBUF, GFP_KERNEL);
	devpriv->ai_urbs = kcalloc(devpriv->n_ai_urbs, sizeof(void *),
				   GFP_KERNEL);
	devpriv->ao_urbs = kcalloc(devpriv->n_ao_urbs, sizeof(void *),
				   GFP_KERNEL);
	if (!devpriv->dux_commands || !devpriv->in_buf || !devpriv->insn_buf ||
	    !devpriv->ai_urbs || !devpriv->ao_urbs)
		return -ENOMEM;

	for (i = 0; i < devpriv->n_ai_urbs; i++) {
		/* one frame: 1ms */
		urb = usb_alloc_urb(1, GFP_KERNEL);
		if (!urb)
			return -ENOMEM;
		devpriv->ai_urbs[i] = urb;

		urb->dev = usb;
		urb->context = dev;
		urb->pipe = usb_rcvisocpipe(usb, 6);
		urb->transfer_flags = URB_ISO_ASAP;
		urb->transfer_buffer = kzalloc(SIZEINBUF, GFP_KERNEL);
		if (!urb->transfer_buffer)
			return -ENOMEM;

		urb->complete = usbduxsub_ai_isoc_irq;
		urb->number_of_packets = 1;
		urb->transfer_buffer_length = SIZEINBUF;
		urb->iso_frame_desc[0].offset = 0;
		urb->iso_frame_desc[0].length = SIZEINBUF;
	}

	for (i = 0; i < devpriv->n_ao_urbs; i++) {
		/* one frame: 1ms */
		urb = usb_alloc_urb(1, GFP_KERNEL);
		if (!urb)
			return -ENOMEM;
		devpriv->ao_urbs[i] = urb;

		urb->dev = usb;
		urb->context = dev;
		urb->pipe = usb_sndisocpipe(usb, 2);
		urb->transfer_flags = URB_ISO_ASAP;
		urb->transfer_buffer = kzalloc(SIZEOUTBUF, GFP_KERNEL);
		if (!urb->transfer_buffer)
			return -ENOMEM;

		urb->complete = usbduxsub_ao_isoc_irq;
		urb->number_of_packets = 1;
		urb->transfer_buffer_length = SIZEOUTBUF;
		urb->iso_frame_desc[0].offset = 0;
		urb->iso_frame_desc[0].length = SIZEOUTBUF;
		if (devpriv->high_speed)
			urb->interval = 8;	/* uframes */
		else
			urb->interval = 1;	/* frames */
	}

	/* pwm */
	if (devpriv->pwm_buf_sz) {
		urb = usb_alloc_urb(0, GFP_KERNEL);
		if (!urb)
			return -ENOMEM;
		devpriv->pwm_urb = urb;

		/* max bulk ep size in high speed */
		urb->transfer_buffer = kzalloc(devpriv->pwm_buf_sz,
					       GFP_KERNEL);
		if (!urb->transfer_buffer)
			return -ENOMEM;
	}

	return 0;
}

static void usbdux_free_usb_buffers(struct comedi_device *dev)
{
	struct usbdux_private *devpriv = dev->private;
	struct urb *urb;
	int i;

	urb = devpriv->pwm_urb;
	if (urb) {
		kfree(urb->transfer_buffer);
		usb_free_urb(urb);
	}
	if (devpriv->ao_urbs) {
		for (i = 0; i < devpriv->n_ao_urbs; i++) {
			urb = devpriv->ao_urbs[i];
			if (urb) {
				kfree(urb->transfer_buffer);
				usb_free_urb(urb);
			}
		}
		kfree(devpriv->ao_urbs);
	}
	if (devpriv->ai_urbs) {
		for (i = 0; i < devpriv->n_ai_urbs; i++) {
			urb = devpriv->ai_urbs[i];
			if (urb) {
				kfree(urb->transfer_buffer);
				usb_free_urb(urb);
			}
		}
		kfree(devpriv->ai_urbs);
	}
	kfree(devpriv->insn_buf);
	kfree(devpriv->in_buf);
	kfree(devpriv->dux_commands);
}

static int usbdux_auto_attach(struct comedi_device *dev,
			      unsigned long context_unused)
{
	struct usb_interface *intf = comedi_to_usb_interface(dev);
	struct usb_device *usb = comedi_to_usb_dev(dev);
	struct usbdux_private *devpriv;
	struct comedi_subdevice *s;
	int ret;

	devpriv = comedi_alloc_devpriv(dev, sizeof(*devpriv));
	if (!devpriv)
		return -ENOMEM;

	mutex_init(&devpriv->mut);

	usb_set_intfdata(intf, devpriv);

	devpriv->high_speed = (usb->speed == USB_SPEED_HIGH);
	if (devpriv->high_speed) {
		devpriv->n_ai_urbs = NUMOFINBUFFERSHIGH;
		devpriv->n_ao_urbs = NUMOFOUTBUFFERSHIGH;
		devpriv->pwm_buf_sz = 512;
	} else {
		devpriv->n_ai_urbs = NUMOFINBUFFERSFULL;
		devpriv->n_ao_urbs = NUMOFOUTBUFFERSFULL;
	}

	ret = usbdux_alloc_usb_buffers(dev);
	if (ret)
		return ret;

	/* setting to alternate setting 3: enabling iso ep and bulk ep. */
	ret = usb_set_interface(usb, intf->altsetting->desc.bInterfaceNumber,
				3);
	if (ret < 0) {
		dev_err(dev->class_dev,
			"could not set alternate setting 3 in high speed\n");
		return ret;
	}

	ret = comedi_load_firmware(dev, &usb->dev, USBDUX_FIRMWARE,
				   usbdux_firmware_upload, 0);
	if (ret < 0)
		return ret;

	ret = comedi_alloc_subdevices(dev, (devpriv->high_speed) ? 5 : 4);
	if (ret)
		return ret;

	/* Analog Input subdevice */
	s = &dev->subdevices[0];
	dev->read_subdev = s;
	s->type		= COMEDI_SUBD_AI;
	s->subdev_flags	= SDF_READABLE | SDF_GROUND | SDF_CMD_READ;
	s->n_chan	= 8;
	s->maxdata	= 0x0fff;
	s->len_chanlist	= 8;
	s->range_table	= &range_usbdux_ai_range;
	s->insn_read	= usbdux_ai_insn_read;
	s->do_cmdtest	= usbdux_ai_cmdtest;
	s->do_cmd	= usbdux_ai_cmd;
	s->cancel	= usbdux_ai_cancel;

	/* Analog Output subdevice */
	s = &dev->subdevices[1];
	dev->write_subdev = s;
	s->type		= COMEDI_SUBD_AO;
	s->subdev_flags	= SDF_WRITABLE | SDF_GROUND | SDF_CMD_WRITE;
	s->n_chan	= 4;
	s->maxdata	= 0x0fff;
	s->len_chanlist	= s->n_chan;
	s->range_table	= &range_usbdux_ao_range;
	s->do_cmdtest	= usbdux_ao_cmdtest;
	s->do_cmd	= usbdux_ao_cmd;
	s->cancel	= usbdux_ao_cancel;
	s->insn_read	= usbdux_ao_insn_read;
	s->insn_write	= usbdux_ao_insn_write;

	ret = comedi_alloc_subdev_readback(s);
	if (ret)
		return ret;

	/* Digital I/O subdevice */
	s = &dev->subdevices[2];
	s->type		= COMEDI_SUBD_DIO;
	s->subdev_flags	= SDF_READABLE | SDF_WRITABLE;
	s->n_chan	= 8;
	s->maxdata	= 1;
	s->range_table	= &range_digital;
	s->insn_bits	= usbdux_dio_insn_bits;
	s->insn_config	= usbdux_dio_insn_config;

	/* Counter subdevice */
	s = &dev->subdevices[3];
	s->type		= COMEDI_SUBD_COUNTER;
	s->subdev_flags	= SDF_WRITABLE | SDF_READABLE;
	s->n_chan	= 4;
	s->maxdata	= 0xffff;
	s->insn_read	= usbdux_counter_read;
	s->insn_write	= usbdux_counter_write;
	s->insn_config	= usbdux_counter_config;

	if (devpriv->high_speed) {
		/* PWM subdevice */
		s = &dev->subdevices[4];
		s->type		= COMEDI_SUBD_PWM;
		s->subdev_flags	= SDF_WRITABLE | SDF_PWM_HBRIDGE;
		s->n_chan	= 8;
		s->maxdata	= devpriv->pwm_buf_sz;
		s->insn_write	= usbdux_pwm_write;
		s->insn_config	= usbdux_pwm_config;

		usbdux_pwm_period(dev, s, PWM_DEFAULT_PERIOD);
	}

	return 0;
}

static void usbdux_detach(struct comedi_device *dev)
{
	struct usb_interface *intf = comedi_to_usb_interface(dev);
	struct usbdux_private *devpriv = dev->private;

	usb_set_intfdata(intf, NULL);

	if (!devpriv)
		return;

	mutex_lock(&devpriv->mut);

	/* force unlink all urbs */
	usbdux_pwm_stop(dev, 1);
	usbdux_ao_stop(dev, 1);
	usbdux_ai_stop(dev, 1);

	usbdux_free_usb_buffers(dev);

	mutex_unlock(&devpriv->mut);

	mutex_destroy(&devpriv->mut);
}

static struct comedi_driver usbdux_driver = {
	.driver_name	= "usbdux",
	.module		= THIS_MODULE,
	.auto_attach	= usbdux_auto_attach,
	.detach		= usbdux_detach,
};

static int usbdux_usb_probe(struct usb_interface *intf,
			    const struct usb_device_id *id)
{
	return comedi_usb_auto_config(intf, &usbdux_driver, 0);
}

static const struct usb_device_id usbdux_usb_table[] = {
	{ USB_DEVICE(0x13d8, 0x0001) },
	{ USB_DEVICE(0x13d8, 0x0002) },
	{ }
};
MODULE_DEVICE_TABLE(usb, usbdux_usb_table);

static struct usb_driver usbdux_usb_driver = {
	.name		= "usbdux",
	.probe		= usbdux_usb_probe,
	.disconnect	= comedi_usb_auto_unconfig,
	.id_table	= usbdux_usb_table,
};
module_comedi_usb_driver(usbdux_driver, usbdux_usb_driver);

MODULE_AUTHOR("Bernd Porr, BerndPorr@f2s.com");
MODULE_DESCRIPTION("Stirling/ITL USB-DUX -- Bernd.Porr@f2s.com");
MODULE_LICENSE("GPL");
MODULE_FIRMWARE(USBDUX_FIRMWARE);