/*
 * usbdux.c
 * Copyright (C) 2003-2014 Bernd Porr, mail@berndporr.me.uk
 *
 * 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.
 */

/*
 * 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);
        unsigned int val = s->readback[chan];
        __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++) {
                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 = 255;

        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);
}

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);