// SPDX-License-Identifier: GPL-2.0
/*
 * quatech_daqp_cs.c
 * Quatech DAQP PCMCIA data capture cards COMEDI client driver
 * Copyright (C) 2000, 2003 Brent Baccala <baccala@freesoft.org>
 * The DAQP interface code in this file is released into the public domain.
 *
 * COMEDI - Linux Control and Measurement Device Interface
 * Copyright (C) 1998 David A. Schleef <ds@schleef.org>
 * https://www.comedi.org/
 *
 * Documentation for the DAQP PCMCIA cards can be found on Quatech's site:
 *      ftp://ftp.quatech.com/Manuals/daqp-208.pdf
 *
 * This manual is for both the DAQP-208 and the DAQP-308.
 *
 * What works:
 * - A/D conversion
 *      - 8 channels
 *      - 4 gain ranges
 *      - ground ref or differential
 *      - single-shot and timed both supported
 * - D/A conversion, single-shot
 * - digital I/O
 *
 * What doesn't:
 * - any kind of triggering - external or D/A channel 1
 * - the card's optional expansion board
 * - the card's timer (for anything other than A/D conversion)
 * - D/A update modes other than immediate (i.e, timed)
 * - fancier timing modes
 * - setting card's FIFO buffer thresholds to anything but default
 */

/*
 * Driver: quatech_daqp_cs
 * Description: Quatech DAQP PCMCIA data capture cards
 * Devices: [Quatech] DAQP-208 (daqp), DAQP-308
 * Author: Brent Baccala <baccala@freesoft.org>
 * Status: works
 */

#include <linux/module.h>
#include <linux/comedi/comedi_pcmcia.h>

/*
 * Register I/O map
 *
 * The D/A and timer registers can be accessed with 16-bit or 8-bit I/O
 * instructions. All other registers can only use 8-bit instructions.
 *
 * The FIFO and scanlist registers require two 8-bit instructions to
 * access the 16-bit data. Data is transferred LSB then MSB.
 */
#define DAQP_AI_FIFO_REG                0x00

#define DAQP_SCANLIST_REG               0x01
#define DAQP_SCANLIST_DIFFERENTIAL      BIT(14)
#define DAQP_SCANLIST_GAIN(x)           (((x) & 0x3) << 12)
#define DAQP_SCANLIST_CHANNEL(x)        (((x) & 0xf) << 8)
#define DAQP_SCANLIST_START             BIT(7)
#define DAQP_SCANLIST_EXT_GAIN(x)       (((x) & 0x3) << 4)
#define DAQP_SCANLIST_EXT_CHANNEL(x)    (((x) & 0xf) << 0)

#define DAQP_CTRL_REG                   0x02
#define DAQP_CTRL_PACER_CLK(x)          (((x) & 0x3) << 6)
#define DAQP_CTRL_PACER_CLK_EXT         DAQP_CTRL_PACER_CLK(0)
#define DAQP_CTRL_PACER_CLK_5MHZ        DAQP_CTRL_PACER_CLK(1)
#define DAQP_CTRL_PACER_CLK_1MHZ        DAQP_CTRL_PACER_CLK(2)
#define DAQP_CTRL_PACER_CLK_100KHZ      DAQP_CTRL_PACER_CLK(3)
#define DAQP_CTRL_EXPANSION             BIT(5)
#define DAQP_CTRL_EOS_INT_ENA           BIT(4)
#define DAQP_CTRL_FIFO_INT_ENA          BIT(3)
#define DAQP_CTRL_TRIG_MODE             BIT(2)  /* 0=one-shot; 1=continuous */
#define DAQP_CTRL_TRIG_SRC              BIT(1)  /* 0=internal; 1=external */
#define DAQP_CTRL_TRIG_EDGE             BIT(0)  /* 0=rising; 1=falling */

#define DAQP_STATUS_REG                 0x02
#define DAQP_STATUS_IDLE                BIT(7)
#define DAQP_STATUS_RUNNING             BIT(6)
#define DAQP_STATUS_DATA_LOST           BIT(5)
#define DAQP_STATUS_END_OF_SCAN         BIT(4)
#define DAQP_STATUS_FIFO_THRESHOLD      BIT(3)
#define DAQP_STATUS_FIFO_FULL           BIT(2)
#define DAQP_STATUS_FIFO_NEARFULL       BIT(1)
#define DAQP_STATUS_FIFO_EMPTY          BIT(0)
/* these bits clear when the status register is read */
#define DAQP_STATUS_EVENTS              (DAQP_STATUS_DATA_LOST |        \
                                         DAQP_STATUS_END_OF_SCAN |      \
                                         DAQP_STATUS_FIFO_THRESHOLD)

#define DAQP_DI_REG                     0x03
#define DAQP_DO_REG                     0x03

#define DAQP_PACER_LOW_REG              0x04
#define DAQP_PACER_MID_REG              0x05
#define DAQP_PACER_HIGH_REG             0x06

#define DAQP_CMD_REG                    0x07
/* the monostable bits are self-clearing after the function is complete */
#define DAQP_CMD_ARM                    BIT(7)  /* monostable */
#define DAQP_CMD_RSTF                   BIT(6)  /* monostable */
#define DAQP_CMD_RSTQ                   BIT(5)  /* monostable */
#define DAQP_CMD_STOP                   BIT(4)  /* monostable */
#define DAQP_CMD_LATCH                  BIT(3)  /* monostable */
#define DAQP_CMD_SCANRATE(x)            (((x) & 0x3) << 1)
#define DAQP_CMD_SCANRATE_100KHZ        DAQP_CMD_SCANRATE(0)
#define DAQP_CMD_SCANRATE_50KHZ         DAQP_CMD_SCANRATE(1)
#define DAQP_CMD_SCANRATE_25KHZ         DAQP_CMD_SCANRATE(2)
#define DAQP_CMD_FIFO_DATA              BIT(0)

#define DAQP_AO_REG                     0x08    /* and 0x09 (16-bit) */

#define DAQP_TIMER_REG                  0x0a    /* and 0x0b (16-bit) */

#define DAQP_AUX_REG                    0x0f
/* Auxiliary Control register bits (write) */
#define DAQP_AUX_EXT_ANALOG_TRIG        BIT(7)
#define DAQP_AUX_PRETRIG                BIT(6)
#define DAQP_AUX_TIMER_INT_ENA          BIT(5)
#define DAQP_AUX_TIMER_MODE(x)          (((x) & 0x3) << 3)
#define DAQP_AUX_TIMER_MODE_RELOAD      DAQP_AUX_TIMER_MODE(0)
#define DAQP_AUX_TIMER_MODE_PAUSE       DAQP_AUX_TIMER_MODE(1)
#define DAQP_AUX_TIMER_MODE_GO          DAQP_AUX_TIMER_MODE(2)
#define DAQP_AUX_TIMER_MODE_EXT         DAQP_AUX_TIMER_MODE(3)
#define DAQP_AUX_TIMER_CLK_SRC_EXT      BIT(2)
#define DAQP_AUX_DA_UPDATE(x)           (((x) & 0x3) << 0)
#define DAQP_AUX_DA_UPDATE_DIRECT       DAQP_AUX_DA_UPDATE(0)
#define DAQP_AUX_DA_UPDATE_OVERFLOW     DAQP_AUX_DA_UPDATE(1)
#define DAQP_AUX_DA_UPDATE_EXTERNAL     DAQP_AUX_DA_UPDATE(2)
#define DAQP_AUX_DA_UPDATE_PACER        DAQP_AUX_DA_UPDATE(3)
/* Auxiliary Status register bits (read) */
#define DAQP_AUX_RUNNING                BIT(7)
#define DAQP_AUX_TRIGGERED              BIT(6)
#define DAQP_AUX_DA_BUFFER              BIT(5)
#define DAQP_AUX_TIMER_OVERFLOW         BIT(4)
#define DAQP_AUX_CONVERSION             BIT(3)
#define DAQP_AUX_DATA_LOST              BIT(2)
#define DAQP_AUX_FIFO_NEARFULL          BIT(1)
#define DAQP_AUX_FIFO_EMPTY             BIT(0)

#define DAQP_FIFO_SIZE                  4096

#define DAQP_MAX_TIMER_SPEED            10000   /* 100 kHz in nanoseconds */

struct daqp_private {
        unsigned int pacer_div;
        int stop;
};

static const struct comedi_lrange range_daqp_ai = {
        4, {
                BIP_RANGE(10),
                BIP_RANGE(5),
                BIP_RANGE(2.5),
                BIP_RANGE(1.25)
        }
};

static int daqp_clear_events(struct comedi_device *dev, int loops)
{
        unsigned int status;

        /*
         * Reset any pending interrupts (my card has a tendency to require
         * multiple reads on the status register to achieve this).
         */
        while (--loops) {
                status = inb(dev->iobase + DAQP_STATUS_REG);
                if ((status & DAQP_STATUS_EVENTS) == 0)
                        return 0;
        }
        dev_err(dev->class_dev, "couldn't clear events in status register\n");
        return -EBUSY;
}

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

        if (devpriv->stop)
                return -EIO;

        /*
         * Stop any conversions, disable interrupts, and clear
         * the status event flags.
         */
        outb(DAQP_CMD_STOP, dev->iobase + DAQP_CMD_REG);
        outb(0, dev->iobase + DAQP_CTRL_REG);
        inb(dev->iobase + DAQP_STATUS_REG);

        return 0;
}

static unsigned int daqp_ai_get_sample(struct comedi_device *dev,
                                       struct comedi_subdevice *s)
{
        unsigned int val;

        /*
         * Get a two's complement sample from the FIFO and
         * return the munged offset binary value.
         */
        val = inb(dev->iobase + DAQP_AI_FIFO_REG);
        val |= inb(dev->iobase + DAQP_AI_FIFO_REG) << 8;
        return comedi_offset_munge(s, val);
}

static irqreturn_t daqp_interrupt(int irq, void *dev_id)
{
        struct comedi_device *dev = dev_id;
        struct comedi_subdevice *s = dev->read_subdev;
        struct comedi_cmd *cmd = &s->async->cmd;
        int loop_limit = 10000;
        int status;

        if (!dev->attached)
                return IRQ_NONE;

        status = inb(dev->iobase + DAQP_STATUS_REG);
        if (!(status & DAQP_STATUS_EVENTS))
                return IRQ_NONE;

        while (!(status & DAQP_STATUS_FIFO_EMPTY)) {
                unsigned short data;

                if (status & DAQP_STATUS_DATA_LOST) {
                        s->async->events |= COMEDI_CB_OVERFLOW;
                        dev_warn(dev->class_dev, "data lost\n");
                        break;
                }

                data = daqp_ai_get_sample(dev, s);
                comedi_buf_write_samples(s, &data, 1);

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

                if ((loop_limit--) <= 0)
                        break;

                status = inb(dev->iobase + DAQP_STATUS_REG);
        }

        if (loop_limit <= 0) {
                dev_warn(dev->class_dev,
                         "loop_limit reached in %s()\n", __func__);
                s->async->events |= COMEDI_CB_ERROR;
        }

        comedi_handle_events(dev, s);

        return IRQ_HANDLED;
}

static void daqp_ai_set_one_scanlist_entry(struct comedi_device *dev,
                                           unsigned int chanspec,
                                           int start)
{
        unsigned int chan = CR_CHAN(chanspec);
        unsigned int range = CR_RANGE(chanspec);
        unsigned int aref = CR_AREF(chanspec);
        unsigned int val;

        val = DAQP_SCANLIST_CHANNEL(chan) | DAQP_SCANLIST_GAIN(range);

        if (aref == AREF_DIFF)
                val |= DAQP_SCANLIST_DIFFERENTIAL;

        if (start)
                val |= DAQP_SCANLIST_START;

        outb(val & 0xff, dev->iobase + DAQP_SCANLIST_REG);
        outb((val >> 8) & 0xff, dev->iobase + DAQP_SCANLIST_REG);
}

static int daqp_ai_eos(struct comedi_device *dev,
                       struct comedi_subdevice *s,
                       struct comedi_insn *insn,
                       unsigned long context)
{
        unsigned int status;

        status = inb(dev->iobase + DAQP_AUX_REG);
        if (status & DAQP_AUX_CONVERSION)
                return 0;
        return -EBUSY;
}

static int daqp_ai_insn_read(struct comedi_device *dev,
                             struct comedi_subdevice *s,
                             struct comedi_insn *insn,
                             unsigned int *data)
{
        struct daqp_private *devpriv = dev->private;
        int ret = 0;
        int i;

        if (devpriv->stop)
                return -EIO;

        outb(0, dev->iobase + DAQP_AUX_REG);

        /* Reset scan list queue */
        outb(DAQP_CMD_RSTQ, dev->iobase + DAQP_CMD_REG);

        /* Program one scan list entry */
        daqp_ai_set_one_scanlist_entry(dev, insn->chanspec, 1);

        /* Reset data FIFO (see page 28 of DAQP User's Manual) */
        outb(DAQP_CMD_RSTF, dev->iobase + DAQP_CMD_REG);

        /* Set trigger - one-shot, internal, no interrupts */
        outb(DAQP_CTRL_PACER_CLK_100KHZ, dev->iobase + DAQP_CTRL_REG);

        ret = daqp_clear_events(dev, 10000);
        if (ret)
                return ret;

        for (i = 0; i < insn->n; i++) {
                /* Start conversion */
                outb(DAQP_CMD_ARM | DAQP_CMD_FIFO_DATA,
                     dev->iobase + DAQP_CMD_REG);

                ret = comedi_timeout(dev, s, insn, daqp_ai_eos, 0);
                if (ret)
                        break;

                /* clear the status event flags */
                inb(dev->iobase + DAQP_STATUS_REG);

                data[i] = daqp_ai_get_sample(dev, s);
        }

        /* stop any conversions and clear the status event flags */
        outb(DAQP_CMD_STOP, dev->iobase + DAQP_CMD_REG);
        inb(dev->iobase + DAQP_STATUS_REG);

        return ret ? ret : insn->n;
}

/* This function converts ns nanoseconds to a counter value suitable
 * for programming the device.  We always use the DAQP's 5 MHz clock,
 * which with its 24-bit counter, allows values up to 84 seconds.
 * Also, the function adjusts ns so that it cooresponds to the actual
 * time that the device will use.
 */

static int daqp_ns_to_timer(unsigned int *ns, unsigned int flags)
{
        int timer;

        timer = *ns / 200;
        *ns = timer * 200;

        return timer;
}

static void daqp_set_pacer(struct comedi_device *dev, unsigned int val)
{
        outb(val & 0xff, dev->iobase + DAQP_PACER_LOW_REG);
        outb((val >> 8) & 0xff, dev->iobase + DAQP_PACER_MID_REG);
        outb((val >> 16) & 0xff, dev->iobase + DAQP_PACER_HIGH_REG);
}

static int daqp_ai_cmdtest(struct comedi_device *dev,
                           struct comedi_subdevice *s,
                           struct comedi_cmd *cmd)
{
        struct daqp_private *devpriv = dev->private;
        int err = 0;
        unsigned int arg;

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

        err |= comedi_check_trigger_src(&cmd->start_src, TRIG_NOW);
        err |= comedi_check_trigger_src(&cmd->scan_begin_src,
                                        TRIG_TIMER | TRIG_FOLLOW);
        err |= comedi_check_trigger_src(&cmd->convert_src,
                                        TRIG_TIMER | 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->scan_begin_src);
        err |= comedi_check_trigger_is_unique(cmd->convert_src);
        err |= comedi_check_trigger_is_unique(cmd->stop_src);

        /* Step 2b : and mutually compatible */

        /* the async command requires a pacer */
        if (cmd->scan_begin_src != TRIG_TIMER && cmd->convert_src != TRIG_TIMER)
                err |= -EINVAL;

        if (err)
                return 2;

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

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

        err |= comedi_check_trigger_arg_min(&cmd->chanlist_len, 1);
        err |= comedi_check_trigger_arg_is(&cmd->scan_end_arg,
                                           cmd->chanlist_len);

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

        if (cmd->convert_src == TRIG_TIMER) {
                err |= comedi_check_trigger_arg_min(&cmd->convert_arg,
                                                    DAQP_MAX_TIMER_SPEED);

                if (cmd->scan_begin_src == TRIG_TIMER) {
                        /*
                         * If both scan_begin and convert are both timer
                         * values, the only way that can make sense is if
                         * the scan time is the number of conversions times
                         * the convert time.
                         */
                        arg = cmd->convert_arg * cmd->scan_end_arg;
                        err |= comedi_check_trigger_arg_is(&cmd->scan_begin_arg,
                                                           arg);
                }
        }

        if (cmd->stop_src == TRIG_COUNT)
                err |= comedi_check_trigger_arg_max(&cmd->stop_arg, 0x00ffffff);
        else    /* TRIG_NONE */
                err |= comedi_check_trigger_arg_is(&cmd->stop_arg, 0);

        if (err)
                return 3;

        /* step 4: fix up any arguments */

        if (cmd->convert_src == TRIG_TIMER) {
                arg = cmd->convert_arg;
                devpriv->pacer_div = daqp_ns_to_timer(&arg, cmd->flags);
                err |= comedi_check_trigger_arg_is(&cmd->convert_arg, arg);
        } else if (cmd->scan_begin_src == TRIG_TIMER) {
                arg = cmd->scan_begin_arg;
                devpriv->pacer_div = daqp_ns_to_timer(&arg, cmd->flags);
                err |= comedi_check_trigger_arg_is(&cmd->scan_begin_arg, arg);
        }

        if (err)
                return 4;

        return 0;
}

static int daqp_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
{
        struct daqp_private *devpriv = dev->private;
        struct comedi_cmd *cmd = &s->async->cmd;
        int scanlist_start_on_every_entry;
        int threshold;
        int ret;
        int i;

        if (devpriv->stop)
                return -EIO;

        outb(0, dev->iobase + DAQP_AUX_REG);

        /* Reset scan list queue */
        outb(DAQP_CMD_RSTQ, dev->iobase + DAQP_CMD_REG);

        /* Program pacer clock
         *
         * There's two modes we can operate in.  If convert_src is
         * TRIG_TIMER, then convert_arg specifies the time between
         * each conversion, so we program the pacer clock to that
         * frequency and set the SCANLIST_START bit on every scanlist
         * entry.  Otherwise, convert_src is TRIG_NOW, which means
         * we want the fastest possible conversions, scan_begin_src
         * is TRIG_TIMER, and scan_begin_arg specifies the time between
         * each scan, so we program the pacer clock to this frequency
         * and only set the SCANLIST_START bit on the first entry.
         */
        daqp_set_pacer(dev, devpriv->pacer_div);

        if (cmd->convert_src == TRIG_TIMER)
                scanlist_start_on_every_entry = 1;
        else
                scanlist_start_on_every_entry = 0;

        /* Program scan list */
        for (i = 0; i < cmd->chanlist_len; i++) {
                int start = (i == 0 || scanlist_start_on_every_entry);

                daqp_ai_set_one_scanlist_entry(dev, cmd->chanlist[i], start);
        }

        /* Now it's time to program the FIFO threshold, basically the
         * number of samples the card will buffer before it interrupts
         * the CPU.
         *
         * If we don't have a stop count, then use half the size of
         * the FIFO (the manufacturer's recommendation).  Consider
         * that the FIFO can hold 2K samples (4K bytes).  With the
         * threshold set at half the FIFO size, we have a margin of
         * error of 1024 samples.  At the chip's maximum sample rate
         * of 100,000 Hz, the CPU would have to delay interrupt
         * service for a full 10 milliseconds in order to lose data
         * here (as opposed to higher up in the kernel).  I've never
         * seen it happen.  However, for slow sample rates it may
         * buffer too much data and introduce too much delay for the
         * user application.
         *
         * If we have a stop count, then things get more interesting.
         * If the stop count is less than the FIFO size (actually
         * three-quarters of the FIFO size - see below), we just use
         * the stop count itself as the threshold, the card interrupts
         * us when that many samples have been taken, and we kill the
         * acquisition at that point and are done.  If the stop count
         * is larger than that, then we divide it by 2 until it's less
         * than three quarters of the FIFO size (we always leave the
         * top quarter of the FIFO as protection against sluggish CPU
         * interrupt response) and use that as the threshold.  So, if
         * the stop count is 4000 samples, we divide by two twice to
         * get 1000 samples, use that as the threshold, take four
         * interrupts to get our 4000 samples and are done.
         *
         * The algorithm could be more clever.  For example, if 81000
         * samples are requested, we could set the threshold to 1500
         * samples and take 54 interrupts to get 81000.  But 54 isn't
         * a power of two, so this algorithm won't find that option.
         * Instead, it'll set the threshold at 1266 and take 64
         * interrupts to get 81024 samples, of which the last 24 will
         * be discarded... but we won't get the last interrupt until
         * they've been collected.  To find the first option, the
         * computer could look at the prime decomposition of the
         * sample count (81000 = 3^4 * 5^3 * 2^3) and factor it into a
         * threshold (1500 = 3 * 5^3 * 2^2) and an interrupt count (54
         * = 3^3 * 2).  Hmmm... a one-line while loop or prime
         * decomposition of integers... I'll leave it the way it is.
         *
         * I'll also note a mini-race condition before ignoring it in
         * the code.  Let's say we're taking 4000 samples, as before.
         * After 1000 samples, we get an interrupt.  But before that
         * interrupt is completely serviced, another sample is taken
         * and loaded into the FIFO.  Since the interrupt handler
         * empties the FIFO before returning, it will read 1001 samples.
         * If that happens four times, we'll end up taking 4004 samples,
         * not 4000.  The interrupt handler will discard the extra four
         * samples (by halting the acquisition with four samples still
         * in the FIFO), but we will have to wait for them.
         *
         * In short, this code works pretty well, but for either of
         * the two reasons noted, might end up waiting for a few more
         * samples than actually requested.  Shouldn't make too much
         * of a difference.
         */

        /* Save away the number of conversions we should perform, and
         * compute the FIFO threshold (in bytes, not samples - that's
         * why we multiple devpriv->count by 2 = sizeof(sample))
         */

        if (cmd->stop_src == TRIG_COUNT) {
                unsigned long long nsamples;
                unsigned long long nbytes;

                nsamples = (unsigned long long)cmd->stop_arg *
                           cmd->scan_end_arg;
                nbytes = nsamples * comedi_bytes_per_sample(s);
                while (nbytes > DAQP_FIFO_SIZE * 3 / 4)
                        nbytes /= 2;
                threshold = nbytes;
        } else {
                threshold = DAQP_FIFO_SIZE / 2;
        }

        /* Reset data FIFO (see page 28 of DAQP User's Manual) */

        outb(DAQP_CMD_RSTF, dev->iobase + DAQP_CMD_REG);

        /* Set FIFO threshold.  First two bytes are near-empty
         * threshold, which is unused; next two bytes are near-full
         * threshold.  We computed the number of bytes we want in the
         * FIFO when the interrupt is generated, what the card wants
         * is actually the number of available bytes left in the FIFO
         * when the interrupt is to happen.
         */

        outb(0x00, dev->iobase + DAQP_AI_FIFO_REG);
        outb(0x00, dev->iobase + DAQP_AI_FIFO_REG);

        outb((DAQP_FIFO_SIZE - threshold) & 0xff,
             dev->iobase + DAQP_AI_FIFO_REG);
        outb((DAQP_FIFO_SIZE - threshold) >> 8, dev->iobase + DAQP_AI_FIFO_REG);

        /* Set trigger - continuous, internal */
        outb(DAQP_CTRL_TRIG_MODE | DAQP_CTRL_PACER_CLK_5MHZ |
             DAQP_CTRL_FIFO_INT_ENA, dev->iobase + DAQP_CTRL_REG);

        ret = daqp_clear_events(dev, 100);
        if (ret)
                return ret;

        /* Start conversion */
        outb(DAQP_CMD_ARM | DAQP_CMD_FIFO_DATA, dev->iobase + DAQP_CMD_REG);

        return 0;
}

static int daqp_ao_empty(struct comedi_device *dev,
                         struct comedi_subdevice *s,
                         struct comedi_insn *insn,
                         unsigned long context)
{
        unsigned int status;

        status = inb(dev->iobase + DAQP_AUX_REG);
        if ((status & DAQP_AUX_DA_BUFFER) == 0)
                return 0;
        return -EBUSY;
}

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

        if (devpriv->stop)
                return -EIO;

        /* Make sure D/A update mode is direct update */
        outb(0, dev->iobase + DAQP_AUX_REG);

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

                /* D/A transfer rate is about 8ms */
                ret = comedi_timeout(dev, s, insn, daqp_ao_empty, 0);
                if (ret)
                        return ret;

                /* write the two's complement value to the channel */
                outw((chan << 12) | comedi_offset_munge(s, val),
                     dev->iobase + DAQP_AO_REG);

                s->readback[chan] = val;
        }

        return insn->n;
}

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

        if (devpriv->stop)
                return -EIO;

        data[0] = inb(dev->iobase + DAQP_DI_REG);

        return insn->n;
}

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

        if (devpriv->stop)
                return -EIO;

        if (comedi_dio_update_state(s, data))
                outb(s->state, dev->iobase + DAQP_DO_REG);

        data[1] = s->state;

        return insn->n;
}

static int daqp_auto_attach(struct comedi_device *dev,
                            unsigned long context)
{
        struct pcmcia_device *link = comedi_to_pcmcia_dev(dev);
        struct daqp_private *devpriv;
        struct comedi_subdevice *s;
        int ret;

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

        link->config_flags |= CONF_AUTO_SET_IO | CONF_ENABLE_IRQ;
        ret = comedi_pcmcia_enable(dev, NULL);
        if (ret)
                return ret;
        dev->iobase = link->resource[0]->start;

        link->priv = dev;
        ret = pcmcia_request_irq(link, daqp_interrupt);
        if (ret == 0)
                dev->irq = link->irq;

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

        s = &dev->subdevices[0];
        s->type         = COMEDI_SUBD_AI;
        s->subdev_flags = SDF_READABLE | SDF_GROUND | SDF_DIFF;
        s->n_chan       = 8;
        s->maxdata      = 0xffff;
        s->range_table  = &range_daqp_ai;
        s->insn_read    = daqp_ai_insn_read;
        if (dev->irq) {
                dev->read_subdev = s;
                s->subdev_flags |= SDF_CMD_READ;
                s->len_chanlist = 2048;
                s->do_cmdtest   = daqp_ai_cmdtest;
                s->do_cmd       = daqp_ai_cmd;
                s->cancel       = daqp_ai_cancel;
        }

        s = &dev->subdevices[1];
        s->type         = COMEDI_SUBD_AO;
        s->subdev_flags = SDF_WRITABLE;
        s->n_chan       = 2;
        s->maxdata      = 0x0fff;
        s->range_table  = &range_bipolar5;
        s->insn_write   = daqp_ao_insn_write;

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

        /*
         * Digital Input subdevice
         * NOTE: The digital input lines are shared:
         *
         * Chan  Normal Mode        Expansion Mode
         * ----  -----------------  ----------------------------
         *  0    DI0, ext. trigger  Same as normal mode
         *  1    DI1                External gain select, lo bit
         *  2    DI2, ext. clock    Same as normal mode
         *  3    DI3                External gain select, hi bit
         */
        s = &dev->subdevices[2];
        s->type         = COMEDI_SUBD_DI;
        s->subdev_flags = SDF_READABLE;
        s->n_chan       = 4;
        s->maxdata      = 1;
        s->insn_bits    = daqp_di_insn_bits;

        /*
         * Digital Output subdevice
         * NOTE: The digital output lines share the same pins on the
         * interface connector as the four external channel selection
         * bits. If expansion mode is used the digital outputs do not
         * work.
         */
        s = &dev->subdevices[3];
        s->type         = COMEDI_SUBD_DO;
        s->subdev_flags = SDF_WRITABLE;
        s->n_chan       = 4;
        s->maxdata      = 1;
        s->insn_bits    = daqp_do_insn_bits;

        return 0;
}

static struct comedi_driver driver_daqp = {
        .driver_name    = "quatech_daqp_cs",
        .module         = THIS_MODULE,
        .auto_attach    = daqp_auto_attach,
        .detach         = comedi_pcmcia_disable,
};

static int daqp_cs_suspend(struct pcmcia_device *link)
{
        struct comedi_device *dev = link->priv;
        struct daqp_private *devpriv = dev ? dev->private : NULL;

        /* Mark the device as stopped, to block IO until later */
        if (devpriv)
                devpriv->stop = 1;

        return 0;
}

static int daqp_cs_resume(struct pcmcia_device *link)
{
        struct comedi_device *dev = link->priv;
        struct daqp_private *devpriv = dev ? dev->private : NULL;

        if (devpriv)
                devpriv->stop = 0;

        return 0;
}

static int daqp_cs_attach(struct pcmcia_device *link)
{
        return comedi_pcmcia_auto_config(link, &driver_daqp);
}

static const struct pcmcia_device_id daqp_cs_id_table[] = {
        PCMCIA_DEVICE_MANF_CARD(0x0137, 0x0027),
        PCMCIA_DEVICE_NULL
};
MODULE_DEVICE_TABLE(pcmcia, daqp_cs_id_table);

static struct pcmcia_driver daqp_cs_driver = {
        .name           = "quatech_daqp_cs",
        .owner          = THIS_MODULE,
        .id_table       = daqp_cs_id_table,
        .probe          = daqp_cs_attach,
        .remove         = comedi_pcmcia_auto_unconfig,
        .suspend        = daqp_cs_suspend,
        .resume         = daqp_cs_resume,
};
module_comedi_pcmcia_driver(driver_daqp, daqp_cs_driver);

MODULE_DESCRIPTION("Comedi driver for Quatech DAQP PCMCIA data capture cards");
MODULE_AUTHOR("Brent Baccala <baccala@freesoft.org>");
MODULE_LICENSE("GPL");