// SPDX-License-Identifier: GPL-2.0+
/*
 * comedi/drivers/ni_labpc_common.c
 *
 * Common support code for "ni_labpc", "ni_labpc_pci" and "ni_labpc_cs".
 *
 * Copyright (C) 2001-2003 Frank Mori Hess <fmhess@users.sourceforge.net>
 */

#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/delay.h>
#include <linux/slab.h>

#include "../comedidev.h"

#include "comedi_8254.h"
#include "8255.h"
#include "ni_labpc.h"
#include "ni_labpc_regs.h"
#include "ni_labpc_isadma.h"

enum scan_mode {
        MODE_SINGLE_CHAN,
        MODE_SINGLE_CHAN_INTERVAL,
        MODE_MULT_CHAN_UP,
        MODE_MULT_CHAN_DOWN,
};

static const struct comedi_lrange range_labpc_plus_ai = {
        16, {
                BIP_RANGE(5),
                BIP_RANGE(4),
                BIP_RANGE(2.5),
                BIP_RANGE(1),
                BIP_RANGE(0.5),
                BIP_RANGE(0.25),
                BIP_RANGE(0.1),
                BIP_RANGE(0.05),
                UNI_RANGE(10),
                UNI_RANGE(8),
                UNI_RANGE(5),
                UNI_RANGE(2),
                UNI_RANGE(1),
                UNI_RANGE(0.5),
                UNI_RANGE(0.2),
                UNI_RANGE(0.1)
        }
};

static const struct comedi_lrange range_labpc_1200_ai = {
        14, {
                BIP_RANGE(5),
                BIP_RANGE(2.5),
                BIP_RANGE(1),
                BIP_RANGE(0.5),
                BIP_RANGE(0.25),
                BIP_RANGE(0.1),
                BIP_RANGE(0.05),
                UNI_RANGE(10),
                UNI_RANGE(5),
                UNI_RANGE(2),
                UNI_RANGE(1),
                UNI_RANGE(0.5),
                UNI_RANGE(0.2),
                UNI_RANGE(0.1)
        }
};

static const struct comedi_lrange range_labpc_ao = {
        2, {
                BIP_RANGE(5),
                UNI_RANGE(10)
        }
};

/*
 * functions that do inb/outb and readb/writeb so we can use
 * function pointers to decide which to use
 */
static unsigned int labpc_inb(struct comedi_device *dev, unsigned long reg)
{
        return inb(dev->iobase + reg);
}

static void labpc_outb(struct comedi_device *dev,
                       unsigned int byte, unsigned long reg)
{
        outb(byte, dev->iobase + reg);
}

static unsigned int labpc_readb(struct comedi_device *dev, unsigned long reg)
{
        return readb(dev->mmio + reg);
}

static void labpc_writeb(struct comedi_device *dev,
                         unsigned int byte, unsigned long reg)
{
        writeb(byte, dev->mmio + reg);
}

static int labpc_cancel(struct comedi_device *dev, struct comedi_subdevice *s)
{
        struct labpc_private *devpriv = dev->private;
        unsigned long flags;

        spin_lock_irqsave(&dev->spinlock, flags);
        devpriv->cmd2 &= ~(CMD2_SWTRIG | CMD2_HWTRIG | CMD2_PRETRIG);
        devpriv->write_byte(dev, devpriv->cmd2, CMD2_REG);
        spin_unlock_irqrestore(&dev->spinlock, flags);

        devpriv->cmd3 = 0;
        devpriv->write_byte(dev, devpriv->cmd3, CMD3_REG);

        return 0;
}

static void labpc_ai_set_chan_and_gain(struct comedi_device *dev,
                                       enum scan_mode mode,
                                       unsigned int chan,
                                       unsigned int range,
                                       unsigned int aref)
{
        const struct labpc_boardinfo *board = dev->board_ptr;
        struct labpc_private *devpriv = dev->private;

        if (board->is_labpc1200) {
                /*
                 * The LabPC-1200 boards do not have a gain
                 * of '0x10'. Skip the range values that would
                 * result in this gain.
                 */
                range += (range > 0) + (range > 7);
        }

        /* munge channel bits for differential/scan disabled mode */
        if ((mode == MODE_SINGLE_CHAN || mode == MODE_SINGLE_CHAN_INTERVAL) &&
            aref == AREF_DIFF)
                chan *= 2;
        devpriv->cmd1 = CMD1_MA(chan);
        devpriv->cmd1 |= CMD1_GAIN(range);

        devpriv->write_byte(dev, devpriv->cmd1, CMD1_REG);
}

static void labpc_setup_cmd6_reg(struct comedi_device *dev,
                                 struct comedi_subdevice *s,
                                 enum scan_mode mode,
                                 enum transfer_type xfer,
                                 unsigned int range,
                                 unsigned int aref,
                                 bool ena_intr)
{
        const struct labpc_boardinfo *board = dev->board_ptr;
        struct labpc_private *devpriv = dev->private;

        if (!board->is_labpc1200)
                return;

        /* reference inputs to ground or common? */
        if (aref != AREF_GROUND)
                devpriv->cmd6 |= CMD6_NRSE;
        else
                devpriv->cmd6 &= ~CMD6_NRSE;

        /* bipolar or unipolar range? */
        if (comedi_range_is_unipolar(s, range))
                devpriv->cmd6 |= CMD6_ADCUNI;
        else
                devpriv->cmd6 &= ~CMD6_ADCUNI;

        /*  interrupt on fifo half full? */
        if (xfer == fifo_half_full_transfer)
                devpriv->cmd6 |= CMD6_HFINTEN;
        else
                devpriv->cmd6 &= ~CMD6_HFINTEN;

        /* enable interrupt on counter a1 terminal count? */
        if (ena_intr)
                devpriv->cmd6 |= CMD6_DQINTEN;
        else
                devpriv->cmd6 &= ~CMD6_DQINTEN;

        /* are we scanning up or down through channels? */
        if (mode == MODE_MULT_CHAN_UP)
                devpriv->cmd6 |= CMD6_SCANUP;
        else
                devpriv->cmd6 &= ~CMD6_SCANUP;

        devpriv->write_byte(dev, devpriv->cmd6, CMD6_REG);
}

static unsigned int labpc_read_adc_fifo(struct comedi_device *dev)
{
        struct labpc_private *devpriv = dev->private;
        unsigned int lsb = devpriv->read_byte(dev, ADC_FIFO_REG);
        unsigned int msb = devpriv->read_byte(dev, ADC_FIFO_REG);

        return (msb << 8) | lsb;
}

static void labpc_clear_adc_fifo(struct comedi_device *dev)
{
        struct labpc_private *devpriv = dev->private;

        devpriv->write_byte(dev, 0x1, ADC_FIFO_CLEAR_REG);
        labpc_read_adc_fifo(dev);
}

static int labpc_ai_eoc(struct comedi_device *dev,
                        struct comedi_subdevice *s,
                        struct comedi_insn *insn,
                        unsigned long context)
{
        struct labpc_private *devpriv = dev->private;

        devpriv->stat1 = devpriv->read_byte(dev, STAT1_REG);
        if (devpriv->stat1 & STAT1_DAVAIL)
                return 0;
        return -EBUSY;
}

static int labpc_ai_insn_read(struct comedi_device *dev,
                              struct comedi_subdevice *s,
                              struct comedi_insn *insn,
                              unsigned int *data)
{
        struct labpc_private *devpriv = dev->private;
        unsigned int chan = CR_CHAN(insn->chanspec);
        unsigned int range = CR_RANGE(insn->chanspec);
        unsigned int aref = CR_AREF(insn->chanspec);
        int ret;
        int i;

        /* disable timed conversions, interrupt generation and dma */
        labpc_cancel(dev, s);

        labpc_ai_set_chan_and_gain(dev, MODE_SINGLE_CHAN, chan, range, aref);

        labpc_setup_cmd6_reg(dev, s, MODE_SINGLE_CHAN, fifo_not_empty_transfer,
                             range, aref, false);

        /* setup cmd4 register */
        devpriv->cmd4 = 0;
        devpriv->cmd4 |= CMD4_ECLKRCV;
        /* single-ended/differential */
        if (aref == AREF_DIFF)
                devpriv->cmd4 |= CMD4_SEDIFF;
        devpriv->write_byte(dev, devpriv->cmd4, CMD4_REG);

        /* initialize pacer counter to prevent any problems */
        comedi_8254_set_mode(devpriv->counter, 0, I8254_MODE2 | I8254_BINARY);

        labpc_clear_adc_fifo(dev);

        for (i = 0; i < insn->n; i++) {
                /* trigger conversion */
                devpriv->write_byte(dev, 0x1, ADC_START_CONVERT_REG);

                ret = comedi_timeout(dev, s, insn, labpc_ai_eoc, 0);
                if (ret)
                        return ret;

                data[i] = labpc_read_adc_fifo(dev);
        }

        return insn->n;
}

static bool labpc_use_continuous_mode(const struct comedi_cmd *cmd,
                                      enum scan_mode mode)
{
        if (mode == MODE_SINGLE_CHAN || cmd->scan_begin_src == TRIG_FOLLOW)
                return true;

        return false;
}

static unsigned int labpc_ai_convert_period(const struct comedi_cmd *cmd,
                                            enum scan_mode mode)
{
        if (cmd->convert_src != TRIG_TIMER)
                return 0;

        if (mode == MODE_SINGLE_CHAN && cmd->scan_begin_src == TRIG_TIMER)
                return cmd->scan_begin_arg;

        return cmd->convert_arg;
}

static void labpc_set_ai_convert_period(struct comedi_cmd *cmd,
                                        enum scan_mode mode, unsigned int ns)
{
        if (cmd->convert_src != TRIG_TIMER)
                return;

        if (mode == MODE_SINGLE_CHAN &&
            cmd->scan_begin_src == TRIG_TIMER) {
                cmd->scan_begin_arg = ns;
                if (cmd->convert_arg > cmd->scan_begin_arg)
                        cmd->convert_arg = cmd->scan_begin_arg;
        } else {
                cmd->convert_arg = ns;
        }
}

static unsigned int labpc_ai_scan_period(const struct comedi_cmd *cmd,
                                         enum scan_mode mode)
{
        if (cmd->scan_begin_src != TRIG_TIMER)
                return 0;

        if (mode == MODE_SINGLE_CHAN && cmd->convert_src == TRIG_TIMER)
                return 0;

        return cmd->scan_begin_arg;
}

static void labpc_set_ai_scan_period(struct comedi_cmd *cmd,
                                     enum scan_mode mode, unsigned int ns)
{
        if (cmd->scan_begin_src != TRIG_TIMER)
                return;

        if (mode == MODE_SINGLE_CHAN && cmd->convert_src == TRIG_TIMER)
                return;

        cmd->scan_begin_arg = ns;
}

/* figures out what counter values to use based on command */
static void labpc_adc_timing(struct comedi_device *dev, struct comedi_cmd *cmd,
                             enum scan_mode mode)
{
        struct comedi_8254 *pacer = dev->pacer;
        unsigned int convert_period = labpc_ai_convert_period(cmd, mode);
        unsigned int scan_period = labpc_ai_scan_period(cmd, mode);
        unsigned int base_period;

        /*
         * If both convert and scan triggers are TRIG_TIMER, then they
         * both rely on counter b0. If only one TRIG_TIMER is used, we
         * can use the generic cascaded timing functions.
         */
        if (convert_period && scan_period) {
                /*
                 * pick the lowest divisor value we can (for maximum input
                 * clock speed on convert and scan counters)
                 */
                pacer->next_div1 = (scan_period - 1) /
                                   (pacer->osc_base * I8254_MAX_COUNT) + 1;

                comedi_check_trigger_arg_min(&pacer->next_div1, 2);
                comedi_check_trigger_arg_max(&pacer->next_div1,
                                             I8254_MAX_COUNT);

                base_period = pacer->osc_base * pacer->next_div1;

                /*  set a0 for conversion frequency and b1 for scan frequency */
                switch (cmd->flags & CMDF_ROUND_MASK) {
                default:
                case CMDF_ROUND_NEAREST:
                        pacer->next_div = DIV_ROUND_CLOSEST(convert_period,
                                                            base_period);
                        pacer->next_div2 = DIV_ROUND_CLOSEST(scan_period,
                                                             base_period);
                        break;
                case CMDF_ROUND_UP:
                        pacer->next_div = DIV_ROUND_UP(convert_period,
                                                       base_period);
                        pacer->next_div2 = DIV_ROUND_UP(scan_period,
                                                        base_period);
                        break;
                case CMDF_ROUND_DOWN:
                        pacer->next_div = convert_period / base_period;
                        pacer->next_div2 = scan_period / base_period;
                        break;
                }
                /*  make sure a0 and b1 values are acceptable */
                comedi_check_trigger_arg_min(&pacer->next_div, 2);
                comedi_check_trigger_arg_max(&pacer->next_div, I8254_MAX_COUNT);
                comedi_check_trigger_arg_min(&pacer->next_div2, 2);
                comedi_check_trigger_arg_max(&pacer->next_div2,
                                             I8254_MAX_COUNT);

                /*  write corrected timings to command */
                labpc_set_ai_convert_period(cmd, mode,
                                            base_period * pacer->next_div);
                labpc_set_ai_scan_period(cmd, mode,
                                         base_period * pacer->next_div2);
        } else if (scan_period) {
                /*
                 * calculate cascaded counter values
                 * that give desired scan timing
                 * (pacer->next_div2 / pacer->next_div1)
                 */
                comedi_8254_cascade_ns_to_timer(pacer, &scan_period,
                                                cmd->flags);
                labpc_set_ai_scan_period(cmd, mode, scan_period);
        } else if (convert_period) {
                /*
                 * calculate cascaded counter values
                 * that give desired conversion timing
                 * (pacer->next_div / pacer->next_div1)
                 */
                comedi_8254_cascade_ns_to_timer(pacer, &convert_period,
                                                cmd->flags);
                /* transfer div2 value so correct timer gets updated */
                pacer->next_div = pacer->next_div2;
                labpc_set_ai_convert_period(cmd, mode, convert_period);
        }
}

static enum scan_mode labpc_ai_scan_mode(const struct comedi_cmd *cmd)
{
        unsigned int chan0;
        unsigned int chan1;

        if (cmd->chanlist_len == 1)
                return MODE_SINGLE_CHAN;

        /* chanlist may be NULL during cmdtest */
        if (!cmd->chanlist)
                return MODE_MULT_CHAN_UP;

        chan0 = CR_CHAN(cmd->chanlist[0]);
        chan1 = CR_CHAN(cmd->chanlist[1]);

        if (chan0 < chan1)
                return MODE_MULT_CHAN_UP;

        if (chan0 > chan1)
                return MODE_MULT_CHAN_DOWN;

        return MODE_SINGLE_CHAN_INTERVAL;
}

static int labpc_ai_check_chanlist(struct comedi_device *dev,
                                   struct comedi_subdevice *s,
                                   struct comedi_cmd *cmd)
{
        enum scan_mode mode = labpc_ai_scan_mode(cmd);
        unsigned int chan0 = CR_CHAN(cmd->chanlist[0]);
        unsigned int range0 = CR_RANGE(cmd->chanlist[0]);
        unsigned int aref0 = CR_AREF(cmd->chanlist[0]);
        int i;

        for (i = 0; i < cmd->chanlist_len; i++) {
                unsigned int chan = CR_CHAN(cmd->chanlist[i]);
                unsigned int range = CR_RANGE(cmd->chanlist[i]);
                unsigned int aref = CR_AREF(cmd->chanlist[i]);

                switch (mode) {
                case MODE_SINGLE_CHAN:
                        break;
                case MODE_SINGLE_CHAN_INTERVAL:
                        if (chan != chan0) {
                                dev_dbg(dev->class_dev,
                                        "channel scanning order specified in chanlist is not supported by hardware\n");
                                return -EINVAL;
                        }
                        break;
                case MODE_MULT_CHAN_UP:
                        if (chan != i) {
                                dev_dbg(dev->class_dev,
                                        "channel scanning order specified in chanlist is not supported by hardware\n");
                                return -EINVAL;
                        }
                        break;
                case MODE_MULT_CHAN_DOWN:
                        if (chan != (cmd->chanlist_len - i - 1)) {
                                dev_dbg(dev->class_dev,
                                        "channel scanning order specified in chanlist is not supported by hardware\n");
                                return -EINVAL;
                        }
                        break;
                }

                if (range != range0) {
                        dev_dbg(dev->class_dev,
                                "entries in chanlist must all have the same range\n");
                        return -EINVAL;
                }

                if (aref != aref0) {
                        dev_dbg(dev->class_dev,
                                "entries in chanlist must all have the same reference\n");
                        return -EINVAL;
                }
        }

        return 0;
}

static int labpc_ai_cmdtest(struct comedi_device *dev,
                            struct comedi_subdevice *s, struct comedi_cmd *cmd)
{
        const struct labpc_boardinfo *board = dev->board_ptr;
        int err = 0;
        int tmp, tmp2;
        unsigned int stop_mask;
        enum scan_mode mode;

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

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

        stop_mask = TRIG_COUNT | TRIG_NONE;
        if (board->is_labpc1200)
                stop_mask |= TRIG_EXT;
        err |= comedi_check_trigger_src(&cmd->stop_src, stop_mask);

        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->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 */

        /* can't have external stop and start triggers at once */
        if (cmd->start_src == TRIG_EXT && cmd->stop_src == TRIG_EXT)
                err++;

        if (err)
                return 2;

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

        switch (cmd->start_src) {
        case TRIG_NOW:
                err |= comedi_check_trigger_arg_is(&cmd->start_arg, 0);
                break;
        case TRIG_EXT:
                /* start_arg value is ignored */
                break;
        }

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

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

        /* make sure scan timing is not too fast */
        if (cmd->scan_begin_src == TRIG_TIMER) {
                if (cmd->convert_src == TRIG_TIMER) {
                        err |= comedi_check_trigger_arg_min(&cmd->
                                                            scan_begin_arg,
                                                            cmd->convert_arg *
                                                            cmd->chanlist_len);
                }
                err |= comedi_check_trigger_arg_min(&cmd->scan_begin_arg,
                                                    board->ai_speed *
                                                    cmd->chanlist_len);
        }

        switch (cmd->stop_src) {
        case TRIG_COUNT:
                err |= comedi_check_trigger_arg_min(&cmd->stop_arg, 1);
                break;
        case TRIG_NONE:
                err |= comedi_check_trigger_arg_is(&cmd->stop_arg, 0);
                break;
                /*
                 * TRIG_EXT doesn't care since it doesn't
                 * trigger off a numbered channel
                 */
        default:
                break;
        }

        if (err)
                return 3;

        /* step 4: fix up any arguments */

        tmp = cmd->convert_arg;
        tmp2 = cmd->scan_begin_arg;
        mode = labpc_ai_scan_mode(cmd);
        labpc_adc_timing(dev, cmd, mode);
        if (tmp != cmd->convert_arg || tmp2 != cmd->scan_begin_arg)
                err++;

        if (err)
                return 4;

        /* Step 5: check channel list if it exists */
        if (cmd->chanlist && cmd->chanlist_len > 0)
                err |= labpc_ai_check_chanlist(dev, s, cmd);

        if (err)
                return 5;

        return 0;
}

static int labpc_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
{
        const struct labpc_boardinfo *board = dev->board_ptr;
        struct labpc_private *devpriv = dev->private;
        struct comedi_async *async = s->async;
        struct comedi_cmd *cmd = &async->cmd;
        enum scan_mode mode = labpc_ai_scan_mode(cmd);
        unsigned int chanspec = (mode == MODE_MULT_CHAN_UP) ?
                                cmd->chanlist[cmd->chanlist_len - 1] :
                                cmd->chanlist[0];
        unsigned int chan = CR_CHAN(chanspec);
        unsigned int range = CR_RANGE(chanspec);
        unsigned int aref = CR_AREF(chanspec);
        enum transfer_type xfer;
        unsigned long flags;

        /* make sure board is disabled before setting up acquisition */
        labpc_cancel(dev, s);

        /*  initialize software conversion count */
        if (cmd->stop_src == TRIG_COUNT)
                devpriv->count = cmd->stop_arg * cmd->chanlist_len;

        /*  setup hardware conversion counter */
        if (cmd->stop_src == TRIG_EXT) {
                /*
                 * load counter a1 with count of 3
                 * (pc+ manual says this is minimum allowed) using mode 0
                 */
                comedi_8254_load(devpriv->counter, 1,
                                 3, I8254_MODE0 | I8254_BINARY);
        } else  {
                /* just put counter a1 in mode 0 to set its output low */
                comedi_8254_set_mode(devpriv->counter, 1,
                                     I8254_MODE0 | I8254_BINARY);
        }

        /* figure out what method we will use to transfer data */
        if (devpriv->dma &&
            (cmd->flags & (CMDF_WAKE_EOS | CMDF_PRIORITY)) == 0) {
                /*
                 * dma unsafe at RT priority,
                 * and too much setup time for CMDF_WAKE_EOS
                 */
                xfer = isa_dma_transfer;
        } else if (board->is_labpc1200 &&
                   (cmd->flags & CMDF_WAKE_EOS) == 0 &&
                   (cmd->stop_src != TRIG_COUNT || devpriv->count > 256)) {
                /*
                 * pc-plus has no fifo-half full interrupt
                 * wake-end-of-scan should interrupt on fifo not empty
                 * make sure we are taking more than just a few points
                 */
                xfer = fifo_half_full_transfer;
        } else {
                xfer = fifo_not_empty_transfer;
        }
        devpriv->current_transfer = xfer;

        labpc_ai_set_chan_and_gain(dev, mode, chan, range, aref);

        labpc_setup_cmd6_reg(dev, s, mode, xfer, range, aref,
                             (cmd->stop_src == TRIG_EXT));

        /* manual says to set scan enable bit on second pass */
        if (mode == MODE_MULT_CHAN_UP || mode == MODE_MULT_CHAN_DOWN) {
                devpriv->cmd1 |= CMD1_SCANEN;
                /*
                 * Need a brief delay before enabling scan, or scan
                 * list will get screwed when you switch between
                 * scan up to scan down mode - dunno why.
                 */
                udelay(1);
                devpriv->write_byte(dev, devpriv->cmd1, CMD1_REG);
        }

        devpriv->write_byte(dev, cmd->chanlist_len, INTERVAL_COUNT_REG);
        /*  load count */
        devpriv->write_byte(dev, 0x1, INTERVAL_STROBE_REG);

        if (cmd->convert_src == TRIG_TIMER ||
            cmd->scan_begin_src == TRIG_TIMER) {
                struct comedi_8254 *pacer = dev->pacer;
                struct comedi_8254 *counter = devpriv->counter;

                comedi_8254_update_divisors(pacer);

                /* set up pacing */
                comedi_8254_load(pacer, 0, pacer->divisor1,
                                 I8254_MODE3 | I8254_BINARY);

                /* set up conversion pacing */
                comedi_8254_set_mode(counter, 0, I8254_MODE2 | I8254_BINARY);
                if (labpc_ai_convert_period(cmd, mode))
                        comedi_8254_write(counter, 0, pacer->divisor);

                /* set up scan pacing */
                if (labpc_ai_scan_period(cmd, mode))
                        comedi_8254_load(pacer, 1, pacer->divisor2,
                                         I8254_MODE2 | I8254_BINARY);
        }

        labpc_clear_adc_fifo(dev);

        if (xfer == isa_dma_transfer)
                labpc_setup_dma(dev, s);

        /*  enable error interrupts */
        devpriv->cmd3 |= CMD3_ERRINTEN;
        /*  enable fifo not empty interrupt? */
        if (xfer == fifo_not_empty_transfer)
                devpriv->cmd3 |= CMD3_FIFOINTEN;
        devpriv->write_byte(dev, devpriv->cmd3, CMD3_REG);

        /*  setup any external triggering/pacing (cmd4 register) */
        devpriv->cmd4 = 0;
        if (cmd->convert_src != TRIG_EXT)
                devpriv->cmd4 |= CMD4_ECLKRCV;
        /*
         * XXX should discard first scan when using interval scanning
         * since manual says it is not synced with scan clock.
         */
        if (!labpc_use_continuous_mode(cmd, mode)) {
                devpriv->cmd4 |= CMD4_INTSCAN;
                if (cmd->scan_begin_src == TRIG_EXT)
                        devpriv->cmd4 |= CMD4_EOIRCV;
        }
        /*  single-ended/differential */
        if (aref == AREF_DIFF)
                devpriv->cmd4 |= CMD4_SEDIFF;
        devpriv->write_byte(dev, devpriv->cmd4, CMD4_REG);

        /*  startup acquisition */

        spin_lock_irqsave(&dev->spinlock, flags);

        /* use 2 cascaded counters for pacing */
        devpriv->cmd2 |= CMD2_TBSEL;

        devpriv->cmd2 &= ~(CMD2_SWTRIG | CMD2_HWTRIG | CMD2_PRETRIG);
        if (cmd->start_src == TRIG_EXT)
                devpriv->cmd2 |= CMD2_HWTRIG;
        else
                devpriv->cmd2 |= CMD2_SWTRIG;
        if (cmd->stop_src == TRIG_EXT)
                devpriv->cmd2 |= (CMD2_HWTRIG | CMD2_PRETRIG);

        devpriv->write_byte(dev, devpriv->cmd2, CMD2_REG);

        spin_unlock_irqrestore(&dev->spinlock, flags);

        return 0;
}

/* read all available samples from ai fifo */
static int labpc_drain_fifo(struct comedi_device *dev)
{
        struct labpc_private *devpriv = dev->private;
        struct comedi_async *async = dev->read_subdev->async;
        struct comedi_cmd *cmd = &async->cmd;
        unsigned short data;
        const int timeout = 10000;
        unsigned int i;

        devpriv->stat1 = devpriv->read_byte(dev, STAT1_REG);

        for (i = 0; (devpriv->stat1 & STAT1_DAVAIL) && i < timeout;
             i++) {
                /*  quit if we have all the data we want */
                if (cmd->stop_src == TRIG_COUNT) {
                        if (devpriv->count == 0)
                                break;
                        devpriv->count--;
                }
                data = labpc_read_adc_fifo(dev);
                comedi_buf_write_samples(dev->read_subdev, &data, 1);
                devpriv->stat1 = devpriv->read_byte(dev, STAT1_REG);
        }
        if (i == timeout) {
                dev_err(dev->class_dev, "ai timeout, fifo never empties\n");
                async->events |= COMEDI_CB_ERROR;
                return -1;
        }

        return 0;
}

/*
 * Makes sure all data acquired by board is transferred to comedi (used
 * when acquisition is terminated by stop_src == TRIG_EXT).
 */
static void labpc_drain_dregs(struct comedi_device *dev)
{
        struct labpc_private *devpriv = dev->private;

        if (devpriv->current_transfer == isa_dma_transfer)
                labpc_drain_dma(dev);

        labpc_drain_fifo(dev);
}

/* interrupt service routine */
static irqreturn_t labpc_interrupt(int irq, void *d)
{
        struct comedi_device *dev = d;
        const struct labpc_boardinfo *board = dev->board_ptr;
        struct labpc_private *devpriv = dev->private;
        struct comedi_subdevice *s = dev->read_subdev;
        struct comedi_async *async;
        struct comedi_cmd *cmd;

        if (!dev->attached) {
                dev_err(dev->class_dev, "premature interrupt\n");
                return IRQ_HANDLED;
        }

        async = s->async;
        cmd = &async->cmd;

        /* read board status */
        devpriv->stat1 = devpriv->read_byte(dev, STAT1_REG);
        if (board->is_labpc1200)
                devpriv->stat2 = devpriv->read_byte(dev, STAT2_REG);

        if ((devpriv->stat1 & (STAT1_GATA0 | STAT1_CNTINT | STAT1_OVERFLOW |
                               STAT1_OVERRUN | STAT1_DAVAIL)) == 0 &&
            (devpriv->stat2 & STAT2_OUTA1) == 0 &&
            (devpriv->stat2 & STAT2_FIFONHF)) {
                return IRQ_NONE;
        }

        if (devpriv->stat1 & STAT1_OVERRUN) {
                /* clear error interrupt */
                devpriv->write_byte(dev, 0x1, ADC_FIFO_CLEAR_REG);
                async->events |= COMEDI_CB_ERROR;
                comedi_handle_events(dev, s);
                dev_err(dev->class_dev, "overrun\n");
                return IRQ_HANDLED;
        }

        if (devpriv->current_transfer == isa_dma_transfer)
                labpc_handle_dma_status(dev);
        else
                labpc_drain_fifo(dev);

        if (devpriv->stat1 & STAT1_CNTINT) {
                dev_err(dev->class_dev, "handled timer interrupt?\n");
                /*  clear it */
                devpriv->write_byte(dev, 0x1, TIMER_CLEAR_REG);
        }

        if (devpriv->stat1 & STAT1_OVERFLOW) {
                /*  clear error interrupt */
                devpriv->write_byte(dev, 0x1, ADC_FIFO_CLEAR_REG);
                async->events |= COMEDI_CB_ERROR;
                comedi_handle_events(dev, s);
                dev_err(dev->class_dev, "overflow\n");
                return IRQ_HANDLED;
        }
        /*  handle external stop trigger */
        if (cmd->stop_src == TRIG_EXT) {
                if (devpriv->stat2 & STAT2_OUTA1) {
                        labpc_drain_dregs(dev);
                        async->events |= COMEDI_CB_EOA;
                }
        }

        /* TRIG_COUNT end of acquisition */
        if (cmd->stop_src == TRIG_COUNT) {
                if (devpriv->count == 0)
                        async->events |= COMEDI_CB_EOA;
        }

        comedi_handle_events(dev, s);
        return IRQ_HANDLED;
}

static void labpc_ao_write(struct comedi_device *dev,
                           struct comedi_subdevice *s,
                           unsigned int chan, unsigned int val)
{
        struct labpc_private *devpriv = dev->private;

        devpriv->write_byte(dev, val & 0xff, DAC_LSB_REG(chan));
        devpriv->write_byte(dev, (val >> 8) & 0xff, DAC_MSB_REG(chan));

        s->readback[chan] = val;
}

static int labpc_ao_insn_write(struct comedi_device *dev,
                               struct comedi_subdevice *s,
                               struct comedi_insn *insn,
                               unsigned int *data)
{
        const struct labpc_boardinfo *board = dev->board_ptr;
        struct labpc_private *devpriv = dev->private;
        unsigned int channel;
        unsigned int range;
        unsigned int i;
        unsigned long flags;

        channel = CR_CHAN(insn->chanspec);

        /*
         * Turn off pacing of analog output channel.
         * NOTE: hardware bug in daqcard-1200 means pacing cannot
         * be independently enabled/disabled for its the two channels.
         */
        spin_lock_irqsave(&dev->spinlock, flags);
        devpriv->cmd2 &= ~CMD2_LDAC(channel);
        devpriv->write_byte(dev, devpriv->cmd2, CMD2_REG);
        spin_unlock_irqrestore(&dev->spinlock, flags);

        /* set range */
        if (board->is_labpc1200) {
                range = CR_RANGE(insn->chanspec);
                if (comedi_range_is_unipolar(s, range))
                        devpriv->cmd6 |= CMD6_DACUNI(channel);
                else
                        devpriv->cmd6 &= ~CMD6_DACUNI(channel);
                /*  write to register */
                devpriv->write_byte(dev, devpriv->cmd6, CMD6_REG);
        }
        /* send data */
        for (i = 0; i < insn->n; i++)
                labpc_ao_write(dev, s, channel, data[i]);

        return insn->n;
}

/* lowlevel write to eeprom/dac */
static void labpc_serial_out(struct comedi_device *dev, unsigned int value,
                             unsigned int value_width)
{
        struct labpc_private *devpriv = dev->private;
        int i;

        for (i = 1; i <= value_width; i++) {
                /*  clear serial clock */
                devpriv->cmd5 &= ~CMD5_SCLK;
                /*  send bits most significant bit first */
                if (value & (1 << (value_width - i)))
                        devpriv->cmd5 |= CMD5_SDATA;
                else
                        devpriv->cmd5 &= ~CMD5_SDATA;
                udelay(1);
                devpriv->write_byte(dev, devpriv->cmd5, CMD5_REG);
                /*  set clock to load bit */
                devpriv->cmd5 |= CMD5_SCLK;
                udelay(1);
                devpriv->write_byte(dev, devpriv->cmd5, CMD5_REG);
        }
}

/* lowlevel read from eeprom */
static unsigned int labpc_serial_in(struct comedi_device *dev)
{
        struct labpc_private *devpriv = dev->private;
        unsigned int value = 0;
        int i;
        const int value_width = 8;      /*  number of bits wide values are */

        for (i = 1; i <= value_width; i++) {
                /*  set serial clock */
                devpriv->cmd5 |= CMD5_SCLK;
                udelay(1);
                devpriv->write_byte(dev, devpriv->cmd5, CMD5_REG);
                /*  clear clock bit */
                devpriv->cmd5 &= ~CMD5_SCLK;
                udelay(1);
                devpriv->write_byte(dev, devpriv->cmd5, CMD5_REG);
                /*  read bits most significant bit first */
                udelay(1);
                devpriv->stat2 = devpriv->read_byte(dev, STAT2_REG);
                if (devpriv->stat2 & STAT2_PROMOUT)
                        value |= 1 << (value_width - i);
        }

        return value;
}

static unsigned int labpc_eeprom_read(struct comedi_device *dev,
                                      unsigned int address)
{
        struct labpc_private *devpriv = dev->private;
        unsigned int value;
        /*  bits to tell eeprom to expect a read */
        const int read_instruction = 0x3;

        /*  8 bit write lengths to eeprom */
        const int write_length = 8;

        /*  enable read/write to eeprom */
        devpriv->cmd5 &= ~CMD5_EEPROMCS;
        udelay(1);
        devpriv->write_byte(dev, devpriv->cmd5, CMD5_REG);
        devpriv->cmd5 |= (CMD5_EEPROMCS | CMD5_WRTPRT);
        udelay(1);
        devpriv->write_byte(dev, devpriv->cmd5, CMD5_REG);

        /*  send read instruction */
        labpc_serial_out(dev, read_instruction, write_length);
        /*  send 8 bit address to read from */
        labpc_serial_out(dev, address, write_length);
        /*  read result */
        value = labpc_serial_in(dev);

        /*  disable read/write to eeprom */
        devpriv->cmd5 &= ~(CMD5_EEPROMCS | CMD5_WRTPRT);
        udelay(1);
        devpriv->write_byte(dev, devpriv->cmd5, CMD5_REG);

        return value;
}

static unsigned int labpc_eeprom_read_status(struct comedi_device *dev)
{
        struct labpc_private *devpriv = dev->private;
        unsigned int value;
        const int read_status_instruction = 0x5;
        const int write_length = 8;     /*  8 bit write lengths to eeprom */

        /*  enable read/write to eeprom */
        devpriv->cmd5 &= ~CMD5_EEPROMCS;
        udelay(1);
        devpriv->write_byte(dev, devpriv->cmd5, CMD5_REG);
        devpriv->cmd5 |= (CMD5_EEPROMCS | CMD5_WRTPRT);
        udelay(1);
        devpriv->write_byte(dev, devpriv->cmd5, CMD5_REG);

        /*  send read status instruction */
        labpc_serial_out(dev, read_status_instruction, write_length);
        /*  read result */
        value = labpc_serial_in(dev);

        /*  disable read/write to eeprom */
        devpriv->cmd5 &= ~(CMD5_EEPROMCS | CMD5_WRTPRT);
        udelay(1);
        devpriv->write_byte(dev, devpriv->cmd5, CMD5_REG);

        return value;
}

static void labpc_eeprom_write(struct comedi_device *dev,
                               unsigned int address, unsigned int value)
{
        struct labpc_private *devpriv = dev->private;
        const int write_enable_instruction = 0x6;
        const int write_instruction = 0x2;
        const int write_length = 8;     /*  8 bit write lengths to eeprom */

        /*  enable read/write to eeprom */
        devpriv->cmd5 &= ~CMD5_EEPROMCS;
        udelay(1);
        devpriv->write_byte(dev, devpriv->cmd5, CMD5_REG);
        devpriv->cmd5 |= (CMD5_EEPROMCS | CMD5_WRTPRT);
        udelay(1);
        devpriv->write_byte(dev, devpriv->cmd5, CMD5_REG);

        /*  send write_enable instruction */
        labpc_serial_out(dev, write_enable_instruction, write_length);
        devpriv->cmd5 &= ~CMD5_EEPROMCS;
        udelay(1);
        devpriv->write_byte(dev, devpriv->cmd5, CMD5_REG);

        /*  send write instruction */
        devpriv->cmd5 |= CMD5_EEPROMCS;
        udelay(1);
        devpriv->write_byte(dev, devpriv->cmd5, CMD5_REG);
        labpc_serial_out(dev, write_instruction, write_length);
        /*  send 8 bit address to write to */
        labpc_serial_out(dev, address, write_length);
        /*  write value */
        labpc_serial_out(dev, value, write_length);
        devpriv->cmd5 &= ~CMD5_EEPROMCS;
        udelay(1);
        devpriv->write_byte(dev, devpriv->cmd5, CMD5_REG);

        /*  disable read/write to eeprom */
        devpriv->cmd5 &= ~(CMD5_EEPROMCS | CMD5_WRTPRT);
        udelay(1);
        devpriv->write_byte(dev, devpriv->cmd5, CMD5_REG);
}

/* writes to 8 bit calibration dacs */
static void write_caldac(struct comedi_device *dev, unsigned int channel,
                         unsigned int value)
{
        struct labpc_private *devpriv = dev->private;

        /*  clear caldac load bit and make sure we don't write to eeprom */
        devpriv->cmd5 &= ~(CMD5_CALDACLD | CMD5_EEPROMCS | CMD5_WRTPRT);
        udelay(1);
        devpriv->write_byte(dev, devpriv->cmd5, CMD5_REG);

        /*  write 4 bit channel */
        labpc_serial_out(dev, channel, 4);
        /*  write 8 bit caldac value */
        labpc_serial_out(dev, value, 8);

        /*  set and clear caldac bit to load caldac value */
        devpriv->cmd5 |= CMD5_CALDACLD;
        udelay(1);
        devpriv->write_byte(dev, devpriv->cmd5, CMD5_REG);
        devpriv->cmd5 &= ~CMD5_CALDACLD;
        udelay(1);
        devpriv->write_byte(dev, devpriv->cmd5, CMD5_REG);
}

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

        /*
         * Only write the last data value to the caldac. Preceding
         * data would be overwritten anyway.
         */
        if (insn->n > 0) {
                unsigned int val = data[insn->n - 1];

                if (s->readback[chan] != val) {
                        write_caldac(dev, chan, val);
                        s->readback[chan] = val;
                }
        }

        return insn->n;
}

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

        /* make sure there isn't already a write in progress */
        status = labpc_eeprom_read_status(dev);
        if ((status & 0x1) == 0)
                return 0;
        return -EBUSY;
}

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

        /* only allow writes to user area of eeprom */
        if (chan < 16 || chan > 127)
                return -EINVAL;

        /*
         * Only write the last data value to the eeprom. Preceding
         * data would be overwritten anyway.
         */
        if (insn->n > 0) {
                unsigned int val = data[insn->n - 1];

                ret = comedi_timeout(dev, s, insn, labpc_eeprom_ready, 0);
                if (ret)
                        return ret;

                labpc_eeprom_write(dev, chan, val);
                s->readback[chan] = val;
        }

        return insn->n;
}

int labpc_common_attach(struct comedi_device *dev,
                        unsigned int irq, unsigned long isr_flags)
{
        const struct labpc_boardinfo *board = dev->board_ptr;
        struct labpc_private *devpriv;
        struct comedi_subdevice *s;
        int ret;
        int i;

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

        if (dev->mmio) {
                devpriv->read_byte = labpc_readb;
                devpriv->write_byte = labpc_writeb;
        } else {
                devpriv->read_byte = labpc_inb;
                devpriv->write_byte = labpc_outb;
        }

        /* initialize board's command registers */
        devpriv->write_byte(dev, devpriv->cmd1, CMD1_REG);
        devpriv->write_byte(dev, devpriv->cmd2, CMD2_REG);
        devpriv->write_byte(dev, devpriv->cmd3, CMD3_REG);
        devpriv->write_byte(dev, devpriv->cmd4, CMD4_REG);
        if (board->is_labpc1200) {
                devpriv->write_byte(dev, devpriv->cmd5, CMD5_REG);
                devpriv->write_byte(dev, devpriv->cmd6, CMD6_REG);
        }

        if (irq) {
                ret = request_irq(irq, labpc_interrupt, isr_flags,
                                  dev->board_name, dev);
                if (ret == 0)
                        dev->irq = irq;
        }

        if (dev->mmio) {
                dev->pacer = comedi_8254_mm_init(dev->mmio + COUNTER_B_BASE_REG,
                                                 I8254_OSC_BASE_2MHZ,
                                                 I8254_IO8, 0);
                devpriv->counter = comedi_8254_mm_init(dev->mmio +
                                                       COUNTER_A_BASE_REG,
                                                       I8254_OSC_BASE_2MHZ,
                                                       I8254_IO8, 0);
        } else {
                dev->pacer = comedi_8254_init(dev->iobase + COUNTER_B_BASE_REG,
                                              I8254_OSC_BASE_2MHZ,
                                              I8254_IO8, 0);
                devpriv->counter = comedi_8254_init(dev->iobase +
                                                    COUNTER_A_BASE_REG,
                                                    I8254_OSC_BASE_2MHZ,
                                                    I8254_IO8, 0);
        }
        if (!dev->pacer || !devpriv->counter)
                return -ENOMEM;

        ret = comedi_alloc_subdevices(dev, 5);
        if (ret)
                return ret;

        /* analog input subdevice */
        s = &dev->subdevices[0];
        s->type         = COMEDI_SUBD_AI;
        s->subdev_flags = SDF_READABLE | SDF_GROUND | SDF_COMMON | SDF_DIFF;
        s->n_chan       = 8;
        s->len_chanlist = 8;
        s->maxdata      = 0x0fff;
        s->range_table  = board->is_labpc1200 ?
                          &range_labpc_1200_ai : &range_labpc_plus_ai;
        s->insn_read    = labpc_ai_insn_read;
        if (dev->irq) {
                dev->read_subdev = s;
                s->subdev_flags |= SDF_CMD_READ;
                s->do_cmd       = labpc_ai_cmd;
                s->do_cmdtest   = labpc_ai_cmdtest;
                s->cancel       = labpc_cancel;
        }

        /* analog output */
        s = &dev->subdevices[1];
        if (board->has_ao) {
                s->type         = COMEDI_SUBD_AO;
                s->subdev_flags = SDF_READABLE | SDF_WRITABLE | SDF_GROUND;
                s->n_chan       = 2;
                s->maxdata      = 0x0fff;
                s->range_table  = &range_labpc_ao;
                s->insn_write   = labpc_ao_insn_write;

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

                /* initialize analog outputs to a known value */
                for (i = 0; i < s->n_chan; i++)
                        labpc_ao_write(dev, s, i, s->maxdata / 2);
        } else {
                s->type         = COMEDI_SUBD_UNUSED;
        }

        /* 8255 dio */
        s = &dev->subdevices[2];
        if (dev->mmio)
                ret = subdev_8255_mm_init(dev, s, NULL, DIO_BASE_REG);
        else
                ret = subdev_8255_init(dev, s, NULL, DIO_BASE_REG);
        if (ret)
                return ret;

        /*  calibration subdevices for boards that have one */
        s = &dev->subdevices[3];
        if (board->is_labpc1200) {
                s->type         = COMEDI_SUBD_CALIB;
                s->subdev_flags = SDF_READABLE | SDF_WRITABLE | SDF_INTERNAL;
                s->n_chan       = 16;
                s->maxdata      = 0xff;
                s->insn_write   = labpc_calib_insn_write;

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

                for (i = 0; i < s->n_chan; i++) {
                        write_caldac(dev, i, s->maxdata / 2);
                        s->readback[i] = s->maxdata / 2;
                }
        } else {
                s->type         = COMEDI_SUBD_UNUSED;
        }

        /* EEPROM (256 bytes) */
        s = &dev->subdevices[4];
        if (board->is_labpc1200) {
                s->type         = COMEDI_SUBD_MEMORY;
                s->subdev_flags = SDF_READABLE | SDF_WRITABLE | SDF_INTERNAL;
                s->n_chan       = 256;
                s->maxdata      = 0xff;
                s->insn_write   = labpc_eeprom_insn_write;

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

                for (i = 0; i < s->n_chan; i++)
                        s->readback[i] = labpc_eeprom_read(dev, i);
        } else {
                s->type         = COMEDI_SUBD_UNUSED;
        }

        return 0;
}
EXPORT_SYMBOL_GPL(labpc_common_attach);

void labpc_common_detach(struct comedi_device *dev)
{
        struct labpc_private *devpriv = dev->private;

        if (devpriv)
                kfree(devpriv->counter);
}
EXPORT_SYMBOL_GPL(labpc_common_detach);

static int __init labpc_common_init(void)
{
        return 0;
}
module_init(labpc_common_init);

static void __exit labpc_common_exit(void)
{
}
module_exit(labpc_common_exit);

MODULE_AUTHOR("Comedi http://www.comedi.org");
MODULE_DESCRIPTION("Comedi helper for ni_labpc, ni_labpc_pci, ni_labpc_cs");
MODULE_LICENSE("GPL");