das1800.c

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/*
    comedi/drivers/das1800.c
    Driver for Keitley das1700/das1800 series boards
    Copyright (C) 2000 Frank Mori Hess <[email protected]>

    COMEDI - Linux Control and Measurement Device Interface
    Copyright (C) 2000 David A. Schleef <[email protected]>

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

************************************************************************
*/
/*
Driver: das1800
Description: Keithley Metrabyte DAS1800 (& compatibles)
Author: Frank Mori Hess <[email protected]>
Devices: [Keithley Metrabyte] DAS-1701ST (das-1701st),
  DAS-1701ST-DA (das-1701st-da), DAS-1701/AO (das-1701ao),
  DAS-1702ST (das-1702st), DAS-1702ST-DA (das-1702st-da),
  DAS-1702HR (das-1702hr), DAS-1702HR-DA (das-1702hr-da),
  DAS-1702/AO (das-1702ao), DAS-1801ST (das-1801st),
  DAS-1801ST-DA (das-1801st-da), DAS-1801HC (das-1801hc),
  DAS-1801AO (das-1801ao), DAS-1802ST (das-1802st),
  DAS-1802ST-DA (das-1802st-da), DAS-1802HR (das-1802hr),
  DAS-1802HR-DA (das-1802hr-da), DAS-1802HC (das-1802hc),
  DAS-1802AO (das-1802ao)
Status: works

The waveform analog output on the 'ao' cards is not supported.
If you need it, send me (Frank Hess) an email.

Configuration options:
  [0] - I/O port base address
  [1] - IRQ (optional, required for timed or externally triggered conversions)
  [2] - DMA0 (optional, requires irq)
  [3] - DMA1 (optional, requires irq and dma0)
*/
/*

This driver supports the following Keithley boards:

das-1701st
das-1701st-da
das-1701ao
das-1702st
das-1702st-da
das-1702hr
das-1702hr-da
das-1702ao
das-1801st
das-1801st-da
das-1801hc
das-1801ao
das-1802st
das-1802st-da
das-1802hr
das-1802hr-da
das-1802hc
das-1802ao

Options:
    [0] - base io address
    [1] - irq (optional, required for timed or externally triggered conversions)
    [2] - dma0 (optional, requires irq)
    [3] - dma1 (optional, requires irq and dma0)

irq can be omitted, although the cmd interface will not work without it.

analog input cmd triggers supported:
    start_src:      TRIG_NOW | TRIG_EXT
    scan_begin_src: TRIG_FOLLOW | TRIG_TIMER | TRIG_EXT
    scan_end_src:   TRIG_COUNT
    convert_src:    TRIG_TIMER | TRIG_EXT (TRIG_EXT requires scan_begin_src == TRIG_FOLLOW)
    stop_src:       TRIG_COUNT | TRIG_EXT | TRIG_NONE

scan_begin_src triggers TRIG_TIMER and TRIG_EXT use the card's
'burst mode' which limits the valid conversion time to 64 microseconds
(convert_arg <= 64000).  This limitation does not apply if scan_begin_src
is TRIG_FOLLOW.

NOTES:
Only the DAS-1801ST has been tested by me.
Unipolar and bipolar ranges cannot be mixed in the channel/gain list.

TODO:
    Make it automatically allocate irq and dma channels if they are not specified
    Add support for analog out on 'ao' cards
    read insn for analog out
*/

#include <linux/interrupt.h>
#include <linux/slab.h>
#include <linux/io.h>
#include "../comedidev.h"

#include <linux/ioport.h>
#include <asm/dma.h>

#include "8253.h"
#include "comedi_fc.h"

/* misc. defines */
#define DAS1800_SIZE           16   /* uses 16 io addresses */
#define FIFO_SIZE              1024 /*  1024 sample fifo */
#define TIMER_BASE             200  /*  5 Mhz master clock */
#define UNIPOLAR               0x4  /*  bit that determines whether input range is uni/bipolar */
#define DMA_BUF_SIZE           0x1ff00  /*  size in bytes of dma buffers */

/* Registers for the das1800 */
#define DAS1800_FIFO            0x0
#define DAS1800_QRAM            0x0
#define DAS1800_DAC             0x0
#define DAS1800_SELECT          0x2
#define   ADC                     0x0
#define   QRAM                    0x1
#define   DAC(a)                  (0x2 + a)
#define DAS1800_DIGITAL         0x3
#define DAS1800_CONTROL_A       0x4
#define   FFEN                    0x1
#define   CGEN                    0x4
#define   CGSL                    0x8
#define   TGEN                    0x10
#define   TGSL                    0x20
#define   ATEN                    0x80
#define DAS1800_CONTROL_B       0x5
#define   DMA_CH5                 0x1
#define   DMA_CH6                 0x2
#define   DMA_CH7                 0x3
#define   DMA_CH5_CH6             0x5
#define   DMA_CH6_CH7             0x6
#define   DMA_CH7_CH5             0x7
#define   DMA_ENABLED             0x3   /* mask used to determine if dma is enabled */
#define   DMA_DUAL                0x4
#define   IRQ3                    0x8
#define   IRQ5                    0x10
#define   IRQ7                    0x18
#define   IRQ10                   0x28
#define   IRQ11                   0x30
#define   IRQ15                   0x38
#define   FIMD                    0x40
#define DAS1800_CONTROL_C       0X6
#define   IPCLK                   0x1
#define   XPCLK                   0x3
#define   BMDE                    0x4
#define   CMEN                    0x8
#define   UQEN                    0x10
#define   SD                      0x40
#define   UB                      0x80
#define DAS1800_STATUS          0x7
/* bits that prevent interrupt status bits (and CVEN) from being cleared on write */
#define   CLEAR_INTR_MASK         (CVEN_MASK | 0x1f)
#define   INT                     0x1
#define   DMATC                   0x2
#define   CT0TC                   0x8
#define   OVF                     0x10
#define   FHF                     0x20
#define   FNE                     0x40
#define   CVEN_MASK               0x40  /*  masks CVEN on write */
#define   CVEN                    0x80
#define DAS1800_BURST_LENGTH    0x8
#define DAS1800_BURST_RATE      0x9
#define DAS1800_QRAM_ADDRESS    0xa
#define DAS1800_COUNTER         0xc

#define IOBASE2                   0x400 /* offset of additional ioports used on 'ao' cards */

enum {
    das1701st, das1701st_da, das1702st, das1702st_da, das1702hr,
    das1702hr_da,
    das1701ao, das1702ao, das1801st, das1801st_da, das1802st, das1802st_da,
    das1802hr, das1802hr_da, das1801hc, das1802hc, das1801ao, das1802ao
};

/* analog input ranges */
static const struct comedi_lrange range_ai_das1801 = {
    8,
    {
     RANGE(-5, 5),
     RANGE(-1, 1),
     RANGE(-0.1, 0.1),
     RANGE(-0.02, 0.02),
     RANGE(0, 5),
     RANGE(0, 1),
     RANGE(0, 0.1),
     RANGE(0, 0.02),
     }
};

static const struct comedi_lrange range_ai_das1802 = {
    8,
    {
     RANGE(-10, 10),
     RANGE(-5, 5),
     RANGE(-2.5, 2.5),
     RANGE(-1.25, 1.25),
     RANGE(0, 10),
     RANGE(0, 5),
     RANGE(0, 2.5),
     RANGE(0, 1.25),
     }
};

struct das1800_board {
    const char *name;
    int ai_speed;       /* max conversion period in nanoseconds */
    int resolution;     /* bits of ai resolution */
    int qram_len;       /* length of card's channel / gain queue */
    int common;     /* supports AREF_COMMON flag */
    int do_n_chan;      /* number of digital output channels */
    int ao_ability;     /* 0 == no analog out, 1 == basic analog out, 2 == waveform analog out */
    int ao_n_chan;      /* number of analog out channels */
    const struct comedi_lrange *range_ai;   /* available input ranges */
};

/* Warning: the maximum conversion speeds listed below are
 * not always achievable depending on board setup (see
 * user manual.)
 */
static const struct das1800_board das1800_boards[] = {
    {
     .name = "das-1701st",
     .ai_speed = 6250,
     .resolution = 12,
     .qram_len = 256,
     .common = 1,
     .do_n_chan = 4,
     .ao_ability = 0,
     .ao_n_chan = 0,
     .range_ai = &range_ai_das1801,
     },
    {
     .name = "das-1701st-da",
     .ai_speed = 6250,
     .resolution = 12,
     .qram_len = 256,
     .common = 1,
     .do_n_chan = 4,
     .ao_ability = 1,
     .ao_n_chan = 4,
     .range_ai = &range_ai_das1801,
     },
    {
     .name = "das-1702st",
     .ai_speed = 6250,
     .resolution = 12,
     .qram_len = 256,
     .common = 1,
     .do_n_chan = 4,
     .ao_ability = 0,
     .ao_n_chan = 0,
     .range_ai = &range_ai_das1802,
     },
    {
     .name = "das-1702st-da",
     .ai_speed = 6250,
     .resolution = 12,
     .qram_len = 256,
     .common = 1,
     .do_n_chan = 4,
     .ao_ability = 1,
     .ao_n_chan = 4,
     .range_ai = &range_ai_das1802,
     },
    {
     .name = "das-1702hr",
     .ai_speed = 20000,
     .resolution = 16,
     .qram_len = 256,
     .common = 1,
     .do_n_chan = 4,
     .ao_ability = 0,
     .ao_n_chan = 0,
     .range_ai = &range_ai_das1802,
     },
    {
     .name = "das-1702hr-da",
     .ai_speed = 20000,
     .resolution = 16,
     .qram_len = 256,
     .common = 1,
     .do_n_chan = 4,
     .ao_ability = 1,
     .ao_n_chan = 2,
     .range_ai = &range_ai_das1802,
     },
    {
     .name = "das-1701ao",
     .ai_speed = 6250,
     .resolution = 12,
     .qram_len = 256,
     .common = 1,
     .do_n_chan = 4,
     .ao_ability = 2,
     .ao_n_chan = 2,
     .range_ai = &range_ai_das1801,
     },
    {
     .name = "das-1702ao",
     .ai_speed = 6250,
     .resolution = 12,
     .qram_len = 256,
     .common = 1,
     .do_n_chan = 4,
     .ao_ability = 2,
     .ao_n_chan = 2,
     .range_ai = &range_ai_das1802,
     },
    {
     .name = "das-1801st",
     .ai_speed = 3000,
     .resolution = 12,
     .qram_len = 256,
     .common = 1,
     .do_n_chan = 4,
     .ao_ability = 0,
     .ao_n_chan = 0,
     .range_ai = &range_ai_das1801,
     },
    {
     .name = "das-1801st-da",
     .ai_speed = 3000,
     .resolution = 12,
     .qram_len = 256,
     .common = 1,
     .do_n_chan = 4,
     .ao_ability = 0,
     .ao_n_chan = 4,
     .range_ai = &range_ai_das1801,
     },
    {
     .name = "das-1802st",
     .ai_speed = 3000,
     .resolution = 12,
     .qram_len = 256,
     .common = 1,
     .do_n_chan = 4,
     .ao_ability = 0,
     .ao_n_chan = 0,
     .range_ai = &range_ai_das1802,
     },
    {
     .name = "das-1802st-da",
     .ai_speed = 3000,
     .resolution = 12,
     .qram_len = 256,
     .common = 1,
     .do_n_chan = 4,
     .ao_ability = 1,
     .ao_n_chan = 4,
     .range_ai = &range_ai_das1802,
     },
    {
     .name = "das-1802hr",
     .ai_speed = 10000,
     .resolution = 16,
     .qram_len = 256,
     .common = 1,
     .do_n_chan = 4,
     .ao_ability = 0,
     .ao_n_chan = 0,
     .range_ai = &range_ai_das1802,
     },
    {
     .name = "das-1802hr-da",
     .ai_speed = 10000,
     .resolution = 16,
     .qram_len = 256,
     .common = 1,
     .do_n_chan = 4,
     .ao_ability = 1,
     .ao_n_chan = 2,
     .range_ai = &range_ai_das1802,
     },
    {
     .name = "das-1801hc",
     .ai_speed = 3000,
     .resolution = 12,
     .qram_len = 64,
     .common = 0,
     .do_n_chan = 8,
     .ao_ability = 1,
     .ao_n_chan = 2,
     .range_ai = &range_ai_das1801,
     },
    {
     .name = "das-1802hc",
     .ai_speed = 3000,
     .resolution = 12,
     .qram_len = 64,
     .common = 0,
     .do_n_chan = 8,
     .ao_ability = 1,
     .ao_n_chan = 2,
     .range_ai = &range_ai_das1802,
     },
    {
     .name = "das-1801ao",
     .ai_speed = 3000,
     .resolution = 12,
     .qram_len = 256,
     .common = 1,
     .do_n_chan = 4,
     .ao_ability = 2,
     .ao_n_chan = 2,
     .range_ai = &range_ai_das1801,
     },
    {
     .name = "das-1802ao",
     .ai_speed = 3000,
     .resolution = 12,
     .qram_len = 256,
     .common = 1,
     .do_n_chan = 4,
     .ao_ability = 2,
     .ao_n_chan = 2,
     .range_ai = &range_ai_das1802,
     },
};

/*
 * Useful for shorthand access to the particular board structure
 */
#define thisboard ((const struct das1800_board *)dev->board_ptr)

struct das1800_private {
    volatile unsigned int count;    /* number of data points left to be taken */
    unsigned int divisor1;  /* value to load into board's counter 1 for timed conversions */
    unsigned int divisor2;  /* value to load into board's counter 2 for timed conversions */
    int do_bits;        /* digital output bits */
    int irq_dma_bits;   /* bits for control register b */
    /* dma bits for control register b, stored so that dma can be
     * turned on and off */
    int dma_bits;
    unsigned int dma0;  /* dma channels used */
    unsigned int dma1;
    volatile unsigned int dma_current;  /* dma channel currently in use */
    uint16_t *ai_buf0;  /* pointers to dma buffers */
    uint16_t *ai_buf1;
    uint16_t *dma_current_buf;  /* pointer to dma buffer currently being used */
    unsigned int dma_transfer_size; /* size of transfer currently used, in bytes */
    unsigned long iobase2;  /* secondary io address used for analog out on 'ao' boards */
    short ao_update_bits;   /* remembers the last write to the 'update' dac */
};

#define devpriv ((struct das1800_private *)dev->private)

/* analog out range for boards with basic analog out */
static const struct comedi_lrange range_ao_1 = {
    1,
    {
     RANGE(-10, 10),
     }
};

/* analog out range for 'ao' boards */
/*
static const struct comedi_lrange range_ao_2 = {
    2,
    {
        RANGE(-10, 10),
        RANGE(-5, 5),
    }
};
*/

static inline uint16_t munge_bipolar_sample(const struct comedi_device *dev,
                        uint16_t sample)
{
    sample += 1 << (thisboard->resolution - 1);
    return sample;
}

static void munge_data(struct comedi_device *dev, uint16_t * array,
               unsigned int num_elements)
{
    unsigned int i;
    int unipolar;

    /* see if card is using a unipolar or bipolar range so we can munge data correctly */
    unipolar = inb(dev->iobase + DAS1800_CONTROL_C) & UB;

    /* convert to unsigned type if we are in a bipolar mode */
    if (!unipolar) {
        for (i = 0; i < num_elements; i++)
            array[i] = munge_bipolar_sample(dev, array[i]);
    }
}

static void das1800_handle_fifo_half_full(struct comedi_device *dev,
                      struct comedi_subdevice *s)
{
    int numPoints = 0;  /* number of points to read */
    struct comedi_cmd *cmd = &s->async->cmd;

    numPoints = FIFO_SIZE / 2;
    /* if we only need some of the points */
    if (cmd->stop_src == TRIG_COUNT && devpriv->count < numPoints)
        numPoints = devpriv->count;
    insw(dev->iobase + DAS1800_FIFO, devpriv->ai_buf0, numPoints);
    munge_data(dev, devpriv->ai_buf0, numPoints);
    cfc_write_array_to_buffer(s, devpriv->ai_buf0,
                  numPoints * sizeof(devpriv->ai_buf0[0]));
    if (cmd->stop_src == TRIG_COUNT)
        devpriv->count -= numPoints;
    return;
}

static void das1800_handle_fifo_not_empty(struct comedi_device *dev,
                      struct comedi_subdevice *s)
{
    short dpnt;
    int unipolar;
    struct comedi_cmd *cmd = &s->async->cmd;

    unipolar = inb(dev->iobase + DAS1800_CONTROL_C) & UB;

    while (inb(dev->iobase + DAS1800_STATUS) & FNE) {
        if (cmd->stop_src == TRIG_COUNT && devpriv->count == 0)
            break;
        dpnt = inw(dev->iobase + DAS1800_FIFO);
        /* convert to unsigned type if we are in a bipolar mode */
        if (!unipolar)
            ;
        dpnt = munge_bipolar_sample(dev, dpnt);
        cfc_write_to_buffer(s, dpnt);
        if (cmd->stop_src == TRIG_COUNT)
            devpriv->count--;
    }

    return;
}

/* Utility function used by das1800_flush_dma() and das1800_handle_dma().
 * Assumes dma lock is held */
static void das1800_flush_dma_channel(struct comedi_device *dev,
                      struct comedi_subdevice *s,
                      unsigned int channel, uint16_t *buffer)
{
    unsigned int num_bytes, num_samples;
    struct comedi_cmd *cmd = &s->async->cmd;

    disable_dma(channel);

    /* clear flip-flop to make sure 2-byte registers
     * get set correctly */
    clear_dma_ff(channel);

    /*  figure out how many points to read */
    num_bytes = devpriv->dma_transfer_size - get_dma_residue(channel);
    num_samples = num_bytes / sizeof(short);

    /* if we only need some of the points */
    if (cmd->stop_src == TRIG_COUNT && devpriv->count < num_samples)
        num_samples = devpriv->count;

    munge_data(dev, buffer, num_samples);
    cfc_write_array_to_buffer(s, buffer, num_bytes);
    if (s->async->cmd.stop_src == TRIG_COUNT)
        devpriv->count -= num_samples;

    return;
}

/* flushes remaining data from board when external trigger has stopped acquisition
 * and we are using dma transfers */
static void das1800_flush_dma(struct comedi_device *dev,
                  struct comedi_subdevice *s)
{
    unsigned long flags;
    const int dual_dma = devpriv->irq_dma_bits & DMA_DUAL;

    flags = claim_dma_lock();
    das1800_flush_dma_channel(dev, s, devpriv->dma_current,
                  devpriv->dma_current_buf);

    if (dual_dma) {
        /*  switch to other channel and flush it */
        if (devpriv->dma_current == devpriv->dma0) {
            devpriv->dma_current = devpriv->dma1;
            devpriv->dma_current_buf = devpriv->ai_buf1;
        } else {
            devpriv->dma_current = devpriv->dma0;
            devpriv->dma_current_buf = devpriv->ai_buf0;
        }
        das1800_flush_dma_channel(dev, s, devpriv->dma_current,
                      devpriv->dma_current_buf);
    }

    release_dma_lock(flags);

    /*  get any remaining samples in fifo */
    das1800_handle_fifo_not_empty(dev, s);

    return;
}

static void das1800_handle_dma(struct comedi_device *dev,
                   struct comedi_subdevice *s, unsigned int status)
{
    unsigned long flags;
    const int dual_dma = devpriv->irq_dma_bits & DMA_DUAL;

    flags = claim_dma_lock();
    das1800_flush_dma_channel(dev, s, devpriv->dma_current,
                  devpriv->dma_current_buf);
    /*  re-enable  dma channel */
    set_dma_addr(devpriv->dma_current,
             virt_to_bus(devpriv->dma_current_buf));
    set_dma_count(devpriv->dma_current, devpriv->dma_transfer_size);
    enable_dma(devpriv->dma_current);
    release_dma_lock(flags);

    if (status & DMATC) {
        /*  clear DMATC interrupt bit */
        outb(CLEAR_INTR_MASK & ~DMATC, dev->iobase + DAS1800_STATUS);
        /*  switch dma channels for next time, if appropriate */
        if (dual_dma) {
            /*  read data from the other channel next time */
            if (devpriv->dma_current == devpriv->dma0) {
                devpriv->dma_current = devpriv->dma1;
                devpriv->dma_current_buf = devpriv->ai_buf1;
            } else {
                devpriv->dma_current = devpriv->dma0;
                devpriv->dma_current_buf = devpriv->ai_buf0;
            }
        }
    }

    return;
}

static int das1800_cancel(struct comedi_device *dev, struct comedi_subdevice *s)
{
    outb(0x0, dev->iobase + DAS1800_STATUS);    /* disable conversions */
    outb(0x0, dev->iobase + DAS1800_CONTROL_B); /* disable interrupts and dma */
    outb(0x0, dev->iobase + DAS1800_CONTROL_A); /* disable and clear fifo and stop triggering */
    if (devpriv->dma0)
        disable_dma(devpriv->dma0);
    if (devpriv->dma1)
        disable_dma(devpriv->dma1);
    return 0;
}

/* the guts of the interrupt handler, that is shared with das1800_ai_poll */
static void das1800_ai_handler(struct comedi_device *dev)
{
    struct comedi_subdevice *s = &dev->subdevices[0];
    struct comedi_async *async = s->async;
    struct comedi_cmd *cmd = &async->cmd;
    unsigned int status = inb(dev->iobase + DAS1800_STATUS);

    async->events = 0;
    /*  select adc for base address + 0 */
    outb(ADC, dev->iobase + DAS1800_SELECT);
    /*  dma buffer full */
    if (devpriv->irq_dma_bits & DMA_ENABLED) {
        /*  look for data from dma transfer even if dma terminal count hasn't happened yet */
        das1800_handle_dma(dev, s, status);
    } else if (status & FHF) {  /*  if fifo half full */
        das1800_handle_fifo_half_full(dev, s);
    } else if (status & FNE) {  /*  if fifo not empty */
        das1800_handle_fifo_not_empty(dev, s);
    }

    async->events |= COMEDI_CB_BLOCK;
    /* if the card's fifo has overflowed */
    if (status & OVF) {
        /*  clear OVF interrupt bit */
        outb(CLEAR_INTR_MASK & ~OVF, dev->iobase + DAS1800_STATUS);
        comedi_error(dev, "DAS1800 FIFO overflow");
        das1800_cancel(dev, s);
        async->events |= COMEDI_CB_ERROR | COMEDI_CB_EOA;
        comedi_event(dev, s);
        return;
    }
    /*  stop taking data if appropriate */
    /* stop_src TRIG_EXT */
    if (status & CT0TC) {
        /*  clear CT0TC interrupt bit */
        outb(CLEAR_INTR_MASK & ~CT0TC, dev->iobase + DAS1800_STATUS);
        /*  make sure we get all remaining data from board before quitting */
        if (devpriv->irq_dma_bits & DMA_ENABLED)
            das1800_flush_dma(dev, s);
        else
            das1800_handle_fifo_not_empty(dev, s);
        das1800_cancel(dev, s); /* disable hardware conversions */
        async->events |= COMEDI_CB_EOA;
    } else if (cmd->stop_src == TRIG_COUNT && devpriv->count == 0) {    /*  stop_src TRIG_COUNT */
        das1800_cancel(dev, s); /* disable hardware conversions */
        async->events |= COMEDI_CB_EOA;
    }

    comedi_event(dev, s);

    return;
}

static int das1800_ai_poll(struct comedi_device *dev,
               struct comedi_subdevice *s)
{
    unsigned long flags;

    /*  prevent race with interrupt handler */
    spin_lock_irqsave(&dev->spinlock, flags);
    das1800_ai_handler(dev);
    spin_unlock_irqrestore(&dev->spinlock, flags);

    return s->async->buf_write_count - s->async->buf_read_count;
}

static irqreturn_t das1800_interrupt(int irq, void *d)
{
    struct comedi_device *dev = d;
    unsigned int status;

    if (dev->attached == 0) {
        comedi_error(dev, "premature interrupt");
        return IRQ_HANDLED;
    }

    /* Prevent race with das1800_ai_poll() on multi processor systems.
     * Also protects indirect addressing in das1800_ai_handler */
    spin_lock(&dev->spinlock);
    status = inb(dev->iobase + DAS1800_STATUS);

    /* if interrupt was not caused by das-1800 */
    if (!(status & INT)) {
        spin_unlock(&dev->spinlock);
        return IRQ_NONE;
    }
    /* clear the interrupt status bit INT */
    outb(CLEAR_INTR_MASK & ~INT, dev->iobase + DAS1800_STATUS);
    /*  handle interrupt */
    das1800_ai_handler(dev);

    spin_unlock(&dev->spinlock);
    return IRQ_HANDLED;
}

/* converts requested conversion timing to timing compatible with
 * hardware, used only when card is in 'burst mode'
 */
static unsigned int burst_convert_arg(unsigned int convert_arg, int round_mode)
{
    unsigned int micro_sec;

    /*  in burst mode, the maximum conversion time is 64 microseconds */
    if (convert_arg > 64000)
        convert_arg = 64000;

    /*  the conversion time must be an integral number of microseconds */
    switch (round_mode) {
    case TRIG_ROUND_NEAREST:
    default:
        micro_sec = (convert_arg + 500) / 1000;
        break;
    case TRIG_ROUND_DOWN:
        micro_sec = convert_arg / 1000;
        break;
    case TRIG_ROUND_UP:
        micro_sec = (convert_arg - 1) / 1000 + 1;
        break;
    }

    /*  return number of nanoseconds */
    return micro_sec * 1000;
}

/* test analog input cmd */
static int das1800_ai_do_cmdtest(struct comedi_device *dev,
                 struct comedi_subdevice *s,
                 struct comedi_cmd *cmd)
{
    int err = 0;
    unsigned int tmp_arg;
    int i;
    int unipolar;

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

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

    if (err)
        return 1;

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

    err |= cfc_check_trigger_is_unique(cmd->start_src);
    err |= cfc_check_trigger_is_unique(cmd->scan_begin_src);
    err |= cfc_check_trigger_is_unique(cmd->convert_src);
    err |= cfc_check_trigger_is_unique(cmd->stop_src);

    /* Step 2b : and mutually compatible */

    if (cmd->scan_begin_src != TRIG_FOLLOW &&
        cmd->convert_src != TRIG_TIMER)
        err |= -EINVAL;

    if (err)
        return 2;

    /* step 3: make sure arguments are trivially compatible */

    if (cmd->start_arg != 0) {
        cmd->start_arg = 0;
        err++;
    }
    if (cmd->convert_src == TRIG_TIMER) {
        if (cmd->convert_arg < thisboard->ai_speed) {
            cmd->convert_arg = thisboard->ai_speed;
            err++;
        }
    }
    if (!cmd->chanlist_len) {
        cmd->chanlist_len = 1;
        err++;
    }
    if (cmd->scan_end_arg != cmd->chanlist_len) {
        cmd->scan_end_arg = cmd->chanlist_len;
        err++;
    }

    switch (cmd->stop_src) {
    case TRIG_COUNT:
        if (!cmd->stop_arg) {
            cmd->stop_arg = 1;
            err++;
        }
        break;
    case TRIG_NONE:
        if (cmd->stop_arg != 0) {
            cmd->stop_arg = 0;
            err++;
        }
        break;
    default:
        break;
    }

    if (err)
        return 3;

    /* step 4: fix up any arguments */

    if (cmd->convert_src == TRIG_TIMER) {
        /*  if we are not in burst mode */
        if (cmd->scan_begin_src == TRIG_FOLLOW) {
            tmp_arg = cmd->convert_arg;
            /* calculate counter values that give desired timing */
            i8253_cascade_ns_to_timer_2div(TIMER_BASE,
                               &(devpriv->divisor1),
                               &(devpriv->divisor2),
                               &(cmd->convert_arg),
                               cmd->
                               flags & TRIG_ROUND_MASK);
            if (tmp_arg != cmd->convert_arg)
                err++;
        }
        /*  if we are in burst mode */
        else {
            /*  check that convert_arg is compatible */
            tmp_arg = cmd->convert_arg;
            cmd->convert_arg =
                burst_convert_arg(cmd->convert_arg,
                          cmd->flags & TRIG_ROUND_MASK);
            if (tmp_arg != cmd->convert_arg)
                err++;

            if (cmd->scan_begin_src == TRIG_TIMER) {
                /*  if scans are timed faster than conversion rate allows */
                if (cmd->convert_arg * cmd->chanlist_len >
                    cmd->scan_begin_arg) {
                    cmd->scan_begin_arg =
                        cmd->convert_arg *
                        cmd->chanlist_len;
                    err++;
                }
                tmp_arg = cmd->scan_begin_arg;
                /* calculate counter values that give desired timing */
                i8253_cascade_ns_to_timer_2div(TIMER_BASE,
                                   &(devpriv->
                                 divisor1),
                                   &(devpriv->
                                 divisor2),
                                   &(cmd->
                                 scan_begin_arg),
                                   cmd->
                                   flags &
                                   TRIG_ROUND_MASK);
                if (tmp_arg != cmd->scan_begin_arg)
                    err++;
            }
        }
    }

    if (err)
        return 4;

    /*  make sure user is not trying to mix unipolar and bipolar ranges */
    if (cmd->chanlist) {
        unipolar = CR_RANGE(cmd->chanlist[0]) & UNIPOLAR;
        for (i = 1; i < cmd->chanlist_len; i++) {
            if (unipolar != (CR_RANGE(cmd->chanlist[i]) & UNIPOLAR)) {
                comedi_error(dev,
                         "unipolar and bipolar ranges cannot be mixed in the chanlist");
                err++;
                break;
            }
        }
    }

    if (err)
        return 5;

    return 0;
}

/* returns appropriate bits for control register a, depending on command */
static int control_a_bits(const struct comedi_cmd *cmd)
{
    int control_a;

    control_a = FFEN;   /* enable fifo */
    if (cmd->stop_src == TRIG_EXT)
        control_a |= ATEN;
    switch (cmd->start_src) {
    case TRIG_EXT:
        control_a |= TGEN | CGSL;
        break;
    case TRIG_NOW:
        control_a |= CGEN;
        break;
    default:
        break;
    }

    return control_a;
}

/* returns appropriate bits for control register c, depending on command */
static int control_c_bits(const struct comedi_cmd *cmd)
{
    int control_c;
    int aref;

    /* set clock source to internal or external, select analog reference,
     * select unipolar / bipolar
     */
    aref = CR_AREF(cmd->chanlist[0]);
    control_c = UQEN;   /* enable upper qram addresses */
    if (aref != AREF_DIFF)
        control_c |= SD;
    if (aref == AREF_COMMON)
        control_c |= CMEN;
    /* if a unipolar range was selected */
    if (CR_RANGE(cmd->chanlist[0]) & UNIPOLAR)
        control_c |= UB;
    switch (cmd->scan_begin_src) {
    case TRIG_FOLLOW:   /*  not in burst mode */
        switch (cmd->convert_src) {
        case TRIG_TIMER:
            /* trig on cascaded counters */
            control_c |= IPCLK;
            break;
        case TRIG_EXT:
            /* trig on falling edge of external trigger */
            control_c |= XPCLK;
            break;
        default:
            break;
        }
        break;
    case TRIG_TIMER:
        /*  burst mode with internal pacer clock */
        control_c |= BMDE | IPCLK;
        break;
    case TRIG_EXT:
        /*  burst mode with external trigger */
        control_c |= BMDE | XPCLK;
        break;
    default:
        break;
    }

    return control_c;
}

/* loads counters with divisor1, divisor2 from private structure */
static int das1800_set_frequency(struct comedi_device *dev)
{
    int err = 0;

    /*  counter 1, mode 2 */
    if (i8254_load(dev->iobase + DAS1800_COUNTER, 0, 1, devpriv->divisor1,
               2))
        err++;
    /*  counter 2, mode 2 */
    if (i8254_load(dev->iobase + DAS1800_COUNTER, 0, 2, devpriv->divisor2,
               2))
        err++;
    if (err)
        return -1;

    return 0;
}

/* sets up counters */
static int setup_counters(struct comedi_device *dev,
              const struct comedi_cmd *cmd)
{
    unsigned int period;

    /*  setup cascaded counters for conversion/scan frequency */
    switch (cmd->scan_begin_src) {
    case TRIG_FOLLOW:   /*  not in burst mode */
        if (cmd->convert_src == TRIG_TIMER) {
            /* set conversion frequency */
            period = cmd->convert_arg;
            i8253_cascade_ns_to_timer_2div(TIMER_BASE,
                               &devpriv->divisor1,
                               &devpriv->divisor2,
                               &period,
                               cmd->flags &
                            TRIG_ROUND_MASK);
            if (das1800_set_frequency(dev) < 0)
                return -1;
        }
        break;
    case TRIG_TIMER:    /*  in burst mode */
        /* set scan frequency */
        period = cmd->scan_begin_arg;
        i8253_cascade_ns_to_timer_2div(TIMER_BASE, &devpriv->divisor1,
                           &devpriv->divisor2, &period,
                           cmd->flags & TRIG_ROUND_MASK);
        if (das1800_set_frequency(dev) < 0)
            return -1;
        break;
    default:
        break;
    }

    /*  setup counter 0 for 'about triggering' */
    if (cmd->stop_src == TRIG_EXT) {
        /*  load counter 0 in mode 0 */
        i8254_load(dev->iobase + DAS1800_COUNTER, 0, 0, 1, 0);
    }

    return 0;
}

/* utility function that suggests a dma transfer size based on the conversion period 'ns' */
static unsigned int suggest_transfer_size(const struct comedi_cmd *cmd)
{
    unsigned int size = DMA_BUF_SIZE;
    static const int sample_size = 2;   /*  size in bytes of one sample from board */
    unsigned int fill_time = 300000000; /*  target time in nanoseconds for filling dma buffer */
    unsigned int max_size;  /*  maximum size we will allow for a transfer */

    /*  make dma buffer fill in 0.3 seconds for timed modes */
    switch (cmd->scan_begin_src) {
    case TRIG_FOLLOW:   /*  not in burst mode */
        if (cmd->convert_src == TRIG_TIMER)
            size = (fill_time / cmd->convert_arg) * sample_size;
        break;
    case TRIG_TIMER:
        size = (fill_time / (cmd->scan_begin_arg * cmd->chanlist_len)) *
            sample_size;
        break;
    default:
        size = DMA_BUF_SIZE;
        break;
    }

    /*  set a minimum and maximum size allowed */
    max_size = DMA_BUF_SIZE;
    /*  if we are taking limited number of conversions, limit transfer size to that */
    if (cmd->stop_src == TRIG_COUNT &&
        cmd->stop_arg * cmd->chanlist_len * sample_size < max_size)
        max_size = cmd->stop_arg * cmd->chanlist_len * sample_size;

    if (size > max_size)
        size = max_size;
    if (size < sample_size)
        size = sample_size;

    return size;
}

/* sets up dma */
static void setup_dma(struct comedi_device *dev, const struct comedi_cmd *cmd)
{
    unsigned long lock_flags;
    const int dual_dma = devpriv->irq_dma_bits & DMA_DUAL;

    if ((devpriv->irq_dma_bits & DMA_ENABLED) == 0)
        return;

    /* determine a reasonable dma transfer size */
    devpriv->dma_transfer_size = suggest_transfer_size(cmd);
    lock_flags = claim_dma_lock();
    disable_dma(devpriv->dma0);
    /* clear flip-flop to make sure 2-byte registers for
     * count and address get set correctly */
    clear_dma_ff(devpriv->dma0);
    set_dma_addr(devpriv->dma0, virt_to_bus(devpriv->ai_buf0));
    /*  set appropriate size of transfer */
    set_dma_count(devpriv->dma0, devpriv->dma_transfer_size);
    devpriv->dma_current = devpriv->dma0;
    devpriv->dma_current_buf = devpriv->ai_buf0;
    enable_dma(devpriv->dma0);
    /*  set up dual dma if appropriate */
    if (dual_dma) {
        disable_dma(devpriv->dma1);
        /* clear flip-flop to make sure 2-byte registers for
         * count and address get set correctly */
        clear_dma_ff(devpriv->dma1);
        set_dma_addr(devpriv->dma1, virt_to_bus(devpriv->ai_buf1));
        /*  set appropriate size of transfer */
        set_dma_count(devpriv->dma1, devpriv->dma_transfer_size);
        enable_dma(devpriv->dma1);
    }
    release_dma_lock(lock_flags);

    return;
}

/* programs channel/gain list into card */
static void program_chanlist(struct comedi_device *dev,
                 const struct comedi_cmd *cmd)
{
    int i, n, chan_range;
    unsigned long irq_flags;
    const int range_mask = 0x3; /* masks unipolar/bipolar bit off range */
    const int range_bitshift = 8;

    n = cmd->chanlist_len;
    /*  spinlock protects indirect addressing */
    spin_lock_irqsave(&dev->spinlock, irq_flags);
    outb(QRAM, dev->iobase + DAS1800_SELECT);   /* select QRAM for baseAddress + 0x0 */
    outb(n - 1, dev->iobase + DAS1800_QRAM_ADDRESS);    /*set QRAM address start */
    /* make channel / gain list */
    for (i = 0; i < n; i++) {
        chan_range =
            CR_CHAN(cmd->chanlist[i]) |
            ((CR_RANGE(cmd->chanlist[i]) & range_mask) <<
             range_bitshift);
        outw(chan_range, dev->iobase + DAS1800_QRAM);
    }
    outb(n - 1, dev->iobase + DAS1800_QRAM_ADDRESS);    /*finish write to QRAM */
    spin_unlock_irqrestore(&dev->spinlock, irq_flags);

    return;
}

/* analog input do_cmd */
static int das1800_ai_do_cmd(struct comedi_device *dev,
                 struct comedi_subdevice *s)
{
    int ret;
    int control_a, control_c;
    struct comedi_async *async = s->async;
    const struct comedi_cmd *cmd = &async->cmd;

    if (!dev->irq) {
        comedi_error(dev,
                 "no irq assigned for das-1800, cannot do hardware conversions");
        return -1;
    }

    /* disable dma on TRIG_WAKE_EOS, or TRIG_RT
     * (because dma in handler is unsafe at hard real-time priority) */
    if (cmd->flags & (TRIG_WAKE_EOS | TRIG_RT))
        devpriv->irq_dma_bits &= ~DMA_ENABLED;
    else
        devpriv->irq_dma_bits |= devpriv->dma_bits;
    /*  interrupt on end of conversion for TRIG_WAKE_EOS */
    if (cmd->flags & TRIG_WAKE_EOS) {
        /*  interrupt fifo not empty */
        devpriv->irq_dma_bits &= ~FIMD;
    } else {
        /*  interrupt fifo half full */
        devpriv->irq_dma_bits |= FIMD;
    }
    /*  determine how many conversions we need */
    if (cmd->stop_src == TRIG_COUNT)
        devpriv->count = cmd->stop_arg * cmd->chanlist_len;

    das1800_cancel(dev, s);

    /*  determine proper bits for control registers */
    control_a = control_a_bits(cmd);
    control_c = control_c_bits(cmd);

    /* setup card and start */
    program_chanlist(dev, cmd);
    ret = setup_counters(dev, cmd);
    if (ret < 0) {
        comedi_error(dev, "Error setting up counters");
        return ret;
    }
    setup_dma(dev, cmd);
    outb(control_c, dev->iobase + DAS1800_CONTROL_C);
    /*  set conversion rate and length for burst mode */
    if (control_c & BMDE) {
        /*  program conversion period with number of microseconds minus 1 */
        outb(cmd->convert_arg / 1000 - 1,
             dev->iobase + DAS1800_BURST_RATE);
        outb(cmd->chanlist_len - 1, dev->iobase + DAS1800_BURST_LENGTH);
    }
    outb(devpriv->irq_dma_bits, dev->iobase + DAS1800_CONTROL_B);   /*  enable irq/dma */
    outb(control_a, dev->iobase + DAS1800_CONTROL_A);   /* enable fifo and triggering */
    outb(CVEN, dev->iobase + DAS1800_STATUS);   /* enable conversions */

    return 0;
}

/* read analog input */
static int das1800_ai_rinsn(struct comedi_device *dev,
                struct comedi_subdevice *s,
                struct comedi_insn *insn, unsigned int *data)
{
    int i, n;
    int chan, range, aref, chan_range;
    int timeout = 1000;
    short dpnt;
    int conv_flags = 0;
    unsigned long irq_flags;

    /* set up analog reference and unipolar / bipolar mode */
    aref = CR_AREF(insn->chanspec);
    conv_flags |= UQEN;
    if (aref != AREF_DIFF)
        conv_flags |= SD;
    if (aref == AREF_COMMON)
        conv_flags |= CMEN;
    /* if a unipolar range was selected */
    if (CR_RANGE(insn->chanspec) & UNIPOLAR)
        conv_flags |= UB;

    outb(conv_flags, dev->iobase + DAS1800_CONTROL_C);  /* software conversion enabled */
    outb(CVEN, dev->iobase + DAS1800_STATUS);   /* enable conversions */
    outb(0x0, dev->iobase + DAS1800_CONTROL_A); /* reset fifo */
    outb(FFEN, dev->iobase + DAS1800_CONTROL_A);

    chan = CR_CHAN(insn->chanspec);
    /* mask of unipolar/bipolar bit from range */
    range = CR_RANGE(insn->chanspec) & 0x3;
    chan_range = chan | (range << 8);
    spin_lock_irqsave(&dev->spinlock, irq_flags);
    outb(QRAM, dev->iobase + DAS1800_SELECT);   /* select QRAM for baseAddress + 0x0 */
    outb(0x0, dev->iobase + DAS1800_QRAM_ADDRESS);  /* set QRAM address start */
    outw(chan_range, dev->iobase + DAS1800_QRAM);
    outb(0x0, dev->iobase + DAS1800_QRAM_ADDRESS);  /*finish write to QRAM */
    outb(ADC, dev->iobase + DAS1800_SELECT);    /* select ADC for baseAddress + 0x0 */

    for (n = 0; n < insn->n; n++) {
        /* trigger conversion */
        outb(0, dev->iobase + DAS1800_FIFO);
        for (i = 0; i < timeout; i++) {
            if (inb(dev->iobase + DAS1800_STATUS) & FNE)
                break;
        }
        if (i == timeout) {
            comedi_error(dev, "timeout");
            n = -ETIME;
            goto exit;
        }
        dpnt = inw(dev->iobase + DAS1800_FIFO);
        /* shift data to offset binary for bipolar ranges */
        if ((conv_flags & UB) == 0)
            dpnt += 1 << (thisboard->resolution - 1);
        data[n] = dpnt;
    }
exit:
    spin_unlock_irqrestore(&dev->spinlock, irq_flags);

    return n;
}

/* writes to an analog output channel */
static int das1800_ao_winsn(struct comedi_device *dev,
                struct comedi_subdevice *s,
                struct comedi_insn *insn, unsigned int *data)
{
    int chan = CR_CHAN(insn->chanspec);
/* int range = CR_RANGE(insn->chanspec); */
    int update_chan = thisboard->ao_n_chan - 1;
    short output;
    unsigned long irq_flags;

    /*   card expects two's complement data */
    output = data[0] - (1 << (thisboard->resolution - 1));
    /*  if the write is to the 'update' channel, we need to remember its value */
    if (chan == update_chan)
        devpriv->ao_update_bits = output;
    /*  write to channel */
    spin_lock_irqsave(&dev->spinlock, irq_flags);
    outb(DAC(chan), dev->iobase + DAS1800_SELECT);  /* select dac channel for baseAddress + 0x0 */
    outw(output, dev->iobase + DAS1800_DAC);
    /*  now we need to write to 'update' channel to update all dac channels */
    if (chan != update_chan) {
        outb(DAC(update_chan), dev->iobase + DAS1800_SELECT);   /* select 'update' channel for baseAddress + 0x0 */
        outw(devpriv->ao_update_bits, dev->iobase + DAS1800_DAC);
    }
    spin_unlock_irqrestore(&dev->spinlock, irq_flags);

    return 1;
}

/* reads from digital input channels */
static int das1800_di_rbits(struct comedi_device *dev,
                struct comedi_subdevice *s,
                struct comedi_insn *insn, unsigned int *data)
{

    data[1] = inb(dev->iobase + DAS1800_DIGITAL) & 0xf;
    data[0] = 0;

    return insn->n;
}

/* writes to digital output channels */
static int das1800_do_wbits(struct comedi_device *dev,
                struct comedi_subdevice *s,
                struct comedi_insn *insn, unsigned int *data)
{
    unsigned int wbits;

    /*  only set bits that have been masked */
    data[0] &= (1 << s->n_chan) - 1;
    wbits = devpriv->do_bits;
    wbits &= ~data[0];
    wbits |= data[0] & data[1];
    devpriv->do_bits = wbits;

    outb(devpriv->do_bits, dev->iobase + DAS1800_DIGITAL);

    data[1] = devpriv->do_bits;

    return insn->n;
}

static int das1800_init_dma(struct comedi_device *dev, unsigned int dma0,
                unsigned int dma1)
{
    unsigned long flags;

    /*  need an irq to do dma */
    if (dev->irq && dma0) {
        /* encode dma0 and dma1 into 2 digit hexadecimal for switch */
        switch ((dma0 & 0x7) | (dma1 << 4)) {
        case 0x5:   /*  dma0 == 5 */
            devpriv->dma_bits |= DMA_CH5;
            break;
        case 0x6:   /*  dma0 == 6 */
            devpriv->dma_bits |= DMA_CH6;
            break;
        case 0x7:   /*  dma0 == 7 */
            devpriv->dma_bits |= DMA_CH7;
            break;
        case 0x65:  /*  dma0 == 5, dma1 == 6 */
            devpriv->dma_bits |= DMA_CH5_CH6;
            break;
        case 0x76:  /*  dma0 == 6, dma1 == 7 */
            devpriv->dma_bits |= DMA_CH6_CH7;
            break;
        case 0x57:  /*  dma0 == 7, dma1 == 5 */
            devpriv->dma_bits |= DMA_CH7_CH5;
            break;
        default:
            dev_err(dev->class_dev,
                "only supports dma channels 5 through 7\n");
            dev_err(dev->class_dev,
                "Dual dma only allows the following combinations:\n");
            dev_err(dev->class_dev,
                "dma 5,6 / 6,7 / or 7,5\n");
            return -EINVAL;
            break;
        }
        if (request_dma(dma0, dev->driver->driver_name)) {
            dev_err(dev->class_dev,
                "failed to allocate dma channel %i\n", dma0);
            return -EINVAL;
        }
        devpriv->dma0 = dma0;
        devpriv->dma_current = dma0;
        if (dma1) {
            if (request_dma(dma1, dev->driver->driver_name)) {
                dev_err(dev->class_dev,
                    "failed to allocate dma channel %i\n",
                    dma1);
                return -EINVAL;
            }
            devpriv->dma1 = dma1;
        }
        devpriv->ai_buf0 = kmalloc(DMA_BUF_SIZE, GFP_KERNEL | GFP_DMA);
        if (devpriv->ai_buf0 == NULL)
            return -ENOMEM;
        devpriv->dma_current_buf = devpriv->ai_buf0;
        if (dma1) {
            devpriv->ai_buf1 =
                kmalloc(DMA_BUF_SIZE, GFP_KERNEL | GFP_DMA);
            if (devpriv->ai_buf1 == NULL)
                return -ENOMEM;
        }
        flags = claim_dma_lock();
        disable_dma(devpriv->dma0);
        set_dma_mode(devpriv->dma0, DMA_MODE_READ);
        if (dma1) {
            disable_dma(devpriv->dma1);
            set_dma_mode(devpriv->dma1, DMA_MODE_READ);
        }
        release_dma_lock(flags);
    }
    return 0;
}

static int das1800_probe(struct comedi_device *dev)
{
    int id;
    int board;

    id = (inb(dev->iobase + DAS1800_DIGITAL) >> 4) & 0xf;   /* get id bits */
    board = ((struct das1800_board *)dev->board_ptr) - das1800_boards;

    switch (id) {
    case 0x3:
        if (board == das1801st_da || board == das1802st_da ||
            board == das1701st_da || board == das1702st_da) {
            dev_dbg(dev->class_dev, "Board model: %s\n",
                das1800_boards[board].name);
            return board;
        }
        printk
            (" Board model (probed, not recommended): das-1800st-da series\n");
        return das1801st;
        break;
    case 0x4:
        if (board == das1802hr_da || board == das1702hr_da) {
            dev_dbg(dev->class_dev, "Board model: %s\n",
                das1800_boards[board].name);
            return board;
        }
        printk
            (" Board model (probed, not recommended): das-1802hr-da\n");
        return das1802hr;
        break;
    case 0x5:
        if (board == das1801ao || board == das1802ao ||
            board == das1701ao || board == das1702ao) {
            dev_dbg(dev->class_dev, "Board model: %s\n",
                das1800_boards[board].name);
            return board;
        }
        printk
            (" Board model (probed, not recommended): das-1800ao series\n");
        return das1801ao;
        break;
    case 0x6:
        if (board == das1802hr || board == das1702hr) {
            dev_dbg(dev->class_dev, "Board model: %s\n",
                das1800_boards[board].name);
            return board;
        }
        printk
            (" Board model (probed, not recommended): das-1802hr\n");
        return das1802hr;
        break;
    case 0x7:
        if (board == das1801st || board == das1802st ||
            board == das1701st || board == das1702st) {
            dev_dbg(dev->class_dev, "Board model: %s\n",
                das1800_boards[board].name);
            return board;
        }
        printk
            (" Board model (probed, not recommended): das-1800st series\n");
        return das1801st;
        break;
    case 0x8:
        if (board == das1801hc || board == das1802hc) {
            dev_dbg(dev->class_dev, "Board model: %s\n",
                das1800_boards[board].name);
            return board;
        }
        printk
            (" Board model (probed, not recommended): das-1800hc series\n");
        return das1801hc;
        break;
    default:
        printk
            (" Board model: probe returned 0x%x (unknown, please report)\n",
             id);
        return board;
        break;
    }
    return -1;
}

static int das1800_attach(struct comedi_device *dev,
              struct comedi_devconfig *it)
{
    struct comedi_subdevice *s;
    unsigned long iobase = it->options[0];
    unsigned int irq = it->options[1];
    unsigned int dma0 = it->options[2];
    unsigned int dma1 = it->options[3];
    unsigned long iobase2;
    int board;
    int retval;

    /* allocate and initialize dev->private */
    if (alloc_private(dev, sizeof(struct das1800_private)) < 0)
        return -ENOMEM;

    printk(KERN_DEBUG "comedi%d: %s: io 0x%lx", dev->minor,
           dev->driver->driver_name, iobase);
    if (irq) {
        printk(KERN_CONT ", irq %u", irq);
        if (dma0) {
            printk(KERN_CONT ", dma %u", dma0);
            if (dma1)
                printk(KERN_CONT " and %u", dma1);
        }
    }
    printk(KERN_CONT "\n");

    if (iobase == 0) {
        dev_err(dev->class_dev, "io base address required\n");
        return -EINVAL;
    }

    /* check if io addresses are available */
    if (!request_region(iobase, DAS1800_SIZE, dev->driver->driver_name)) {
        printk
            (" I/O port conflict: failed to allocate ports 0x%lx to 0x%lx\n",
             iobase, iobase + DAS1800_SIZE - 1);
        return -EIO;
    }
    dev->iobase = iobase;

    board = das1800_probe(dev);
    if (board < 0) {
        dev_err(dev->class_dev, "unable to determine board type\n");
        return -ENODEV;
    }

    dev->board_ptr = das1800_boards + board;
    dev->board_name = thisboard->name;

    /*  if it is an 'ao' board with fancy analog out then we need extra io ports */
    if (thisboard->ao_ability == 2) {
        iobase2 = iobase + IOBASE2;
        if (!request_region(iobase2, DAS1800_SIZE,
                    dev->driver->driver_name)) {
            printk
                (" I/O port conflict: failed to allocate ports 0x%lx to 0x%lx\n",
                 iobase2, iobase2 + DAS1800_SIZE - 1);
            return -EIO;
        }
        devpriv->iobase2 = iobase2;
    }

    /* grab our IRQ */
    if (irq) {
        if (request_irq(irq, das1800_interrupt, 0,
                dev->driver->driver_name, dev)) {
            dev_dbg(dev->class_dev, "unable to allocate irq %u\n",
                irq);
            return -EINVAL;
        }
    }
    dev->irq = irq;

    /*  set bits that tell card which irq to use */
    switch (irq) {
    case 0:
        break;
    case 3:
        devpriv->irq_dma_bits |= 0x8;
        break;
    case 5:
        devpriv->irq_dma_bits |= 0x10;
        break;
    case 7:
        devpriv->irq_dma_bits |= 0x18;
        break;
    case 10:
        devpriv->irq_dma_bits |= 0x28;
        break;
    case 11:
        devpriv->irq_dma_bits |= 0x30;
        break;
    case 15:
        devpriv->irq_dma_bits |= 0x38;
        break;
    default:
        dev_err(dev->class_dev, "irq out of range\n");
        return -EINVAL;
        break;
    }

    retval = das1800_init_dma(dev, dma0, dma1);
    if (retval < 0)
        return retval;

    if (devpriv->ai_buf0 == NULL) {
        devpriv->ai_buf0 =
            kmalloc(FIFO_SIZE * sizeof(uint16_t), GFP_KERNEL);
        if (devpriv->ai_buf0 == NULL)
            return -ENOMEM;
    }

    retval = comedi_alloc_subdevices(dev, 4);
    if (retval)
        return retval;

    /* analog input subdevice */
    s = &dev->subdevices[0];
    dev->read_subdev = s;
    s->type = COMEDI_SUBD_AI;
    s->subdev_flags = SDF_READABLE | SDF_DIFF | SDF_GROUND | SDF_CMD_READ;
    if (thisboard->common)
        s->subdev_flags |= SDF_COMMON;
    s->n_chan = thisboard->qram_len;
    s->len_chanlist = thisboard->qram_len;
    s->maxdata = (1 << thisboard->resolution) - 1;
    s->range_table = thisboard->range_ai;
    s->do_cmd = das1800_ai_do_cmd;
    s->do_cmdtest = das1800_ai_do_cmdtest;
    s->insn_read = das1800_ai_rinsn;
    s->poll = das1800_ai_poll;
    s->cancel = das1800_cancel;

    /* analog out */
    s = &dev->subdevices[1];
    if (thisboard->ao_ability == 1) {
        s->type = COMEDI_SUBD_AO;
        s->subdev_flags = SDF_WRITABLE;
        s->n_chan = thisboard->ao_n_chan;
        s->maxdata = (1 << thisboard->resolution) - 1;
        s->range_table = &range_ao_1;
        s->insn_write = das1800_ao_winsn;
    } else {
        s->type = COMEDI_SUBD_UNUSED;
    }

    /* di */
    s = &dev->subdevices[2];
    s->type = COMEDI_SUBD_DI;
    s->subdev_flags = SDF_READABLE;
    s->n_chan = 4;
    s->maxdata = 1;
    s->range_table = &range_digital;
    s->insn_bits = das1800_di_rbits;

    /* do */
    s = &dev->subdevices[3];
    s->type = COMEDI_SUBD_DO;
    s->subdev_flags = SDF_WRITABLE | SDF_READABLE;
    s->n_chan = thisboard->do_n_chan;
    s->maxdata = 1;
    s->range_table = &range_digital;
    s->insn_bits = das1800_do_wbits;

    das1800_cancel(dev, dev->read_subdev);

    /*  initialize digital out channels */
    outb(devpriv->do_bits, dev->iobase + DAS1800_DIGITAL);

    /*  initialize analog out channels */
    if (thisboard->ao_ability == 1) {
        /*  select 'update' dac channel for baseAddress + 0x0 */
        outb(DAC(thisboard->ao_n_chan - 1),
             dev->iobase + DAS1800_SELECT);
        outw(devpriv->ao_update_bits, dev->iobase + DAS1800_DAC);
    }

    return 0;
};

static void das1800_detach(struct comedi_device *dev)
{
    if (dev->iobase)
        release_region(dev->iobase, DAS1800_SIZE);
    if (dev->irq)
        free_irq(dev->irq, dev);
    if (dev->private) {
        if (devpriv->iobase2)
            release_region(devpriv->iobase2, DAS1800_SIZE);
        if (devpriv->dma0)
            free_dma(devpriv->dma0);
        if (devpriv->dma1)
            free_dma(devpriv->dma1);
        kfree(devpriv->ai_buf0);
        kfree(devpriv->ai_buf1);
    }
};

static struct comedi_driver das1800_driver = {
    .driver_name    = "das1800",
    .module     = THIS_MODULE,
    .attach     = das1800_attach,
    .detach     = das1800_detach,
    .num_names  = ARRAY_SIZE(das1800_boards),
    .board_name = &das1800_boards[0].name,
    .offset     = sizeof(struct das1800_board),
};
module_comedi_driver(das1800_driver);

MODULE_AUTHOR("Comedi http://www.comedi.org");
MODULE_DESCRIPTION("Comedi low-level driver");
MODULE_LICENSE("GPL");