/*
 * comedi/drivers/pcl818.c
 *
 * Driver: pcl818
 * Description: Advantech PCL-818 cards, PCL-718
 * Author: Michal Dobes <dobes@tesnet.cz>
 * Devices: [Advantech] PCL-818L (pcl818l), PCL-818H (pcl818h),
 *   PCL-818HD (pcl818hd), PCL-818HG (pcl818hg), PCL-818 (pcl818),
 *   PCL-718 (pcl718)
 * Status: works
 *
 * All cards have 16 SE/8 DIFF ADCs, one or two DACs, 16 DI and 16 DO.
 * Differences are only at maximal sample speed, range list and FIFO
 * support.
 * The driver support AI mode 0, 1, 3 other subdevices (AO, DI, DO) support
 * only mode 0. If DMA/FIFO/INT are disabled then AI support only mode 0.
 * PCL-818HD and PCL-818HG support 1kword FIFO. Driver support this FIFO
 * but this code is untested.
 * A word or two about DMA. Driver support DMA operations at two ways:
 * 1) DMA uses two buffers and after one is filled then is generated
 *    INT and DMA restart with second buffer. With this mode I'm unable run
 *    more that 80Ksamples/secs without data dropouts on K6/233.
 * 2) DMA uses one buffer and run in autoinit mode and the data are
 *    from DMA buffer moved on the fly with 2kHz interrupts from RTC.
 *    This mode is used if the interrupt 8 is available for allocation.
 *    If not, then first DMA mode is used. With this I can run at
 *    full speed one card (100ksamples/secs) or two cards with
 *    60ksamples/secs each (more is problem on account of ISA limitations).
 *    To use this mode you must have compiled  kernel with disabled
 *    "Enhanced Real Time Clock Support".
 *    Maybe you can have problems if you use xntpd or similar.
 *    If you've data dropouts with DMA mode 2 then:
 *     a) disable IDE DMA
 *     b) switch text mode console to fb.
 *
 *  Options for PCL-818L:
 *  [0] - IO Base
 *  [1] - IRQ        (0=disable, 2, 3, 4, 5, 6, 7)
 *  [2] - DMA        (0=disable, 1, 3)
 *  [3] - 0, 10=10MHz clock for 8254
 *            1= 1MHz clock for 8254
 *  [4] - 0,  5=A/D input  -5V.. +5V
 *        1, 10=A/D input -10V..+10V
 *  [5] - 0,  5=D/A output 0-5V  (internal reference -5V)
 *        1, 10=D/A output 0-10V (internal reference -10V)
 *        2    =D/A output unknown (external reference)
 *
 *  Options for PCL-818, PCL-818H:
 *  [0] - IO Base
 *  [1] - IRQ        (0=disable, 2, 3, 4, 5, 6, 7)
 *  [2] - DMA        (0=disable, 1, 3)
 *  [3] - 0, 10=10MHz clock for 8254
 *            1= 1MHz clock for 8254
 *  [4] - 0,  5=D/A output 0-5V  (internal reference -5V)
 *        1, 10=D/A output 0-10V (internal reference -10V)
 *        2    =D/A output unknown (external reference)
 *
 *  Options for PCL-818HD, PCL-818HG:
 *  [0] - IO Base
 *  [1] - IRQ        (0=disable, 2, 3, 4, 5, 6, 7)
 *  [2] - DMA/FIFO  (-1=use FIFO, 0=disable both FIFO and DMA,
 *                    1=use DMA ch 1, 3=use DMA ch 3)
 *  [3] - 0, 10=10MHz clock for 8254
 *            1= 1MHz clock for 8254
 *  [4] - 0,  5=D/A output 0-5V  (internal reference -5V)
 *        1, 10=D/A output 0-10V (internal reference -10V)
 *        2    =D/A output unknown (external reference)
 *
 *  Options for PCL-718:
 *  [0] - IO Base
 *  [1] - IRQ        (0=disable, 2, 3, 4, 5, 6, 7)
 *  [2] - DMA        (0=disable, 1, 3)
 *  [3] - 0, 10=10MHz clock for 8254
 *            1= 1MHz clock for 8254
 *  [4] -     0=A/D Range is +/-10V
 *            1=             +/-5V
 *            2=             +/-2.5V
 *            3=             +/-1V
 *            4=             +/-0.5V
 *            5=             user defined bipolar
 *            6=             0-10V
 *            7=             0-5V
 *            8=             0-2V
 *            9=             0-1V
 *           10=             user defined unipolar
 *  [5] - 0,  5=D/A outputs 0-5V  (internal reference -5V)
 *        1, 10=D/A outputs 0-10V (internal reference -10V)
 *            2=D/A outputs unknown (external reference)
 *  [6] - 0, 60=max  60kHz A/D sampling
 *        1,100=max 100kHz A/D sampling (PCL-718 with Option 001 installed)
 *
 */

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

#include "../comedidev.h"

#include "comedi_isadma.h"
#include "comedi_8254.h"

/* boards constants */

#define boardPCL818L 0
#define boardPCL818H 1
#define boardPCL818HD 2
#define boardPCL818HG 3
#define boardPCL818 4
#define boardPCL718 5

/*
 * Register I/O map
 */
#define PCL818_AI_LSB_REG                       0x00
#define PCL818_AI_MSB_REG                       0x01
#define PCL818_RANGE_REG                        0x01
#define PCL818_MUX_REG                          0x02
#define PCL818_MUX_SCAN(_first, _last)          (((_last) << 4) | (_first))
#define PCL818_DO_DI_LSB_REG                    0x03
#define PCL818_AO_LSB_REG(x)                    (0x04 + ((x) * 2))
#define PCL818_AO_MSB_REG(x)                    (0x05 + ((x) * 2))
#define PCL818_STATUS_REG                       0x08
#define PCL818_STATUS_NEXT_CHAN_MASK            (0xf << 0)
#define PCL818_STATUS_INT                       (1 << 4)
#define PCL818_STATUS_MUX                       (1 << 5)
#define PCL818_STATUS_UNI                       (1 << 6)
#define PCL818_STATUS_EOC                       (1 << 7)
#define PCL818_CTRL_REG                         0x09
#define PCL818_CTRL_DISABLE_TRIG                (0 << 0)
#define PCL818_CTRL_SOFT_TRIG                   (1 << 0)
#define PCL818_CTRL_EXT_TRIG                    (2 << 0)
#define PCL818_CTRL_PACER_TRIG                  (3 << 0)
#define PCL818_CTRL_DMAE                        (1 << 2)
#define PCL818_CTRL_IRQ(x)                      ((x) << 4)
#define PCL818_CTRL_INTE                        (1 << 7)
#define PCL818_CNTENABLE_REG                    0x0a
#define PCL818_CNTENABLE_PACER_ENA              (0 << 0)
#define PCL818_CNTENABLE_PACER_TRIG0            (1 << 0)
#define PCL818_CNTENABLE_CNT0_EXT_CLK           (0 << 1)
#define PCL818_CNTENABLE_CNT0_INT_CLK           (1 << 1)
#define PCL818_DO_DI_MSB_REG                    0x0b
#define PCL818_TIMER_BASE                       0x0c

/* W: fifo enable/disable */
#define PCL818_FI_ENABLE 6
/* W: fifo interrupt clear */
#define PCL818_FI_INTCLR 20
/* W: fifo interrupt clear */
#define PCL818_FI_FLUSH 25
/* R: fifo status */
#define PCL818_FI_STATUS 25
/* R: one record from FIFO */
#define PCL818_FI_DATALO 23
#define PCL818_FI_DATAHI 24

#define MAGIC_DMA_WORD 0x5a5a

static const struct comedi_lrange range_pcl818h_ai = {
        9, {
                BIP_RANGE(5),
                BIP_RANGE(2.5),
                BIP_RANGE(1.25),
                BIP_RANGE(0.625),
                UNI_RANGE(10),
                UNI_RANGE(5),
                UNI_RANGE(2.5),
                UNI_RANGE(1.25),
                BIP_RANGE(10)
        }
};

static const struct comedi_lrange range_pcl818hg_ai = {
        10, {
                BIP_RANGE(5),
                BIP_RANGE(0.5),
                BIP_RANGE(0.05),
                BIP_RANGE(0.005),
                UNI_RANGE(10),
                UNI_RANGE(1),
                UNI_RANGE(0.1),
                UNI_RANGE(0.01),
                BIP_RANGE(10),
                BIP_RANGE(1),
                BIP_RANGE(0.1),
                BIP_RANGE(0.01)
        }
};

static const struct comedi_lrange range_pcl818l_l_ai = {
        4, {
                BIP_RANGE(5),
                BIP_RANGE(2.5),
                BIP_RANGE(1.25),
                BIP_RANGE(0.625)
        }
};

static const struct comedi_lrange range_pcl818l_h_ai = {
        4, {
                BIP_RANGE(10),
                BIP_RANGE(5),
                BIP_RANGE(2.5),
                BIP_RANGE(1.25)
        }
};

static const struct comedi_lrange range718_bipolar1 = {
        1, {
                BIP_RANGE(1)
        }
};

static const struct comedi_lrange range718_bipolar0_5 = {
        1, {
                BIP_RANGE(0.5)
        }
};

static const struct comedi_lrange range718_unipolar2 = {
        1, {
                UNI_RANGE(2)
        }
};

static const struct comedi_lrange range718_unipolar1 = {
        1, {
                BIP_RANGE(1)
        }
};

struct pcl818_board {
        const char *name;
        unsigned int ns_min;
        int n_aochan;
        const struct comedi_lrange *ai_range_type;
        unsigned int has_dma:1;
        unsigned int has_fifo:1;
        unsigned int is_818:1;
};

static const struct pcl818_board boardtypes[] = {
        {
                .name           = "pcl818l",
                .ns_min         = 25000,
                .n_aochan       = 1,
                .ai_range_type  = &range_pcl818l_l_ai,
                .has_dma        = 1,
                .is_818         = 1,
        }, {
                .name           = "pcl818h",
                .ns_min         = 10000,
                .n_aochan       = 1,
                .ai_range_type  = &range_pcl818h_ai,
                .has_dma        = 1,
                .is_818         = 1,
        }, {
                .name           = "pcl818hd",
                .ns_min         = 10000,
                .n_aochan       = 1,
                .ai_range_type  = &range_pcl818h_ai,
                .has_dma        = 1,
                .has_fifo       = 1,
                .is_818         = 1,
        }, {
                .name           = "pcl818hg",
                .ns_min         = 10000,
                .n_aochan       = 1,
                .ai_range_type  = &range_pcl818hg_ai,
                .has_dma        = 1,
                .has_fifo       = 1,
                .is_818         = 1,
        }, {
                .name           = "pcl818",
                .ns_min         = 10000,
                .n_aochan       = 2,
                .ai_range_type  = &range_pcl818h_ai,
                .has_dma        = 1,
                .is_818         = 1,
        }, {
                .name           = "pcl718",
                .ns_min         = 16000,
                .n_aochan       = 2,
                .ai_range_type  = &range_unipolar5,
                .has_dma        = 1,
        }, {
                .name           = "pcm3718",
                .ns_min         = 10000,
                .ai_range_type  = &range_pcl818h_ai,
                .has_dma        = 1,
                .is_818         = 1,
        },
};

struct pcl818_private {
        struct comedi_isadma *dma;
        /*  manimal allowed delay between samples (in us) for actual card */
        unsigned int ns_min;
        /*  MUX setting for actual AI operations */
        unsigned int act_chanlist[16];
        unsigned int act_chanlist_len;  /*  how long is actual MUX list */
        unsigned int act_chanlist_pos;  /*  actual position in MUX list */
        unsigned int usefifo:1;
        unsigned int ai_cmd_running:1;
        unsigned int ai_cmd_canceled:1;
};

static void pcl818_ai_setup_dma(struct comedi_device *dev,
                                struct comedi_subdevice *s,
                                unsigned int unread_samples)
{
        struct pcl818_private *devpriv = dev->private;
        struct comedi_isadma *dma = devpriv->dma;
        struct comedi_isadma_desc *desc = &dma->desc[dma->cur_dma];
        unsigned int max_samples = comedi_bytes_to_samples(s, desc->maxsize);
        unsigned int nsamples;

        comedi_isadma_disable(dma->chan);

        /*
         * Determine dma size based on the buffer maxsize plus the number of
         * unread samples and the number of samples remaining in the command.
         */
        nsamples = comedi_nsamples_left(s, max_samples + unread_samples);
        if (nsamples > unread_samples) {
                nsamples -= unread_samples;
                desc->size = comedi_samples_to_bytes(s, nsamples);
                comedi_isadma_program(desc);
        }
}

static void pcl818_ai_set_chan_range(struct comedi_device *dev,
                                     unsigned int chan,
                                     unsigned int range)
{
        outb(chan, dev->iobase + PCL818_MUX_REG);
        outb(range, dev->iobase + PCL818_RANGE_REG);
}

static void pcl818_ai_set_chan_scan(struct comedi_device *dev,
                                    unsigned int first_chan,
                                    unsigned int last_chan)
{
        outb(PCL818_MUX_SCAN(first_chan, last_chan),
             dev->iobase + PCL818_MUX_REG);
}

static void pcl818_ai_setup_chanlist(struct comedi_device *dev,
                                     unsigned int *chanlist,
                                     unsigned int seglen)
{
        struct pcl818_private *devpriv = dev->private;
        unsigned int first_chan = CR_CHAN(chanlist[0]);
        unsigned int last_chan;
        unsigned int range;
        int i;

        devpriv->act_chanlist_len = seglen;
        devpriv->act_chanlist_pos = 0;

        /* store range list to card */
        for (i = 0; i < seglen; i++) {
                last_chan = CR_CHAN(chanlist[i]);
                range = CR_RANGE(chanlist[i]);

                devpriv->act_chanlist[i] = last_chan;

                pcl818_ai_set_chan_range(dev, last_chan, range);
        }

        udelay(1);

        pcl818_ai_set_chan_scan(dev, first_chan, last_chan);
}

static void pcl818_ai_clear_eoc(struct comedi_device *dev)
{
        /* writing any value clears the interrupt request */
        outb(0, dev->iobase + PCL818_STATUS_REG);
}

static void pcl818_ai_soft_trig(struct comedi_device *dev)
{
        /* writing any value triggers a software conversion */
        outb(0, dev->iobase + PCL818_AI_LSB_REG);
}

static unsigned int pcl818_ai_get_fifo_sample(struct comedi_device *dev,
                                              struct comedi_subdevice *s,
                                              unsigned int *chan)
{
        unsigned int val;

        val = inb(dev->iobase + PCL818_FI_DATALO);
        val |= (inb(dev->iobase + PCL818_FI_DATAHI) << 8);

        if (chan)
                *chan = val & 0xf;

        return (val >> 4) & s->maxdata;
}

static unsigned int pcl818_ai_get_sample(struct comedi_device *dev,
                                         struct comedi_subdevice *s,
                                         unsigned int *chan)
{
        unsigned int val;

        val = inb(dev->iobase + PCL818_AI_MSB_REG) << 8;
        val |= inb(dev->iobase + PCL818_AI_LSB_REG);

        if (chan)
                *chan = val & 0xf;

        return (val >> 4) & s->maxdata;
}

static int pcl818_ai_eoc(struct comedi_device *dev,
                         struct comedi_subdevice *s,
                         struct comedi_insn *insn,
                         unsigned long context)
{
        unsigned int status;

        status = inb(dev->iobase + PCL818_STATUS_REG);
        if (status & PCL818_STATUS_INT)
                return 0;
        return -EBUSY;
}

static bool pcl818_ai_write_sample(struct comedi_device *dev,
                                   struct comedi_subdevice *s,
                                   unsigned int chan, unsigned int val)
{
        struct pcl818_private *devpriv = dev->private;
        struct comedi_cmd *cmd = &s->async->cmd;
        unsigned int expected_chan;

        expected_chan = devpriv->act_chanlist[devpriv->act_chanlist_pos];
        if (chan != expected_chan) {
                dev_dbg(dev->class_dev,
                        "A/D mode1/3 %s - channel dropout %d!=%d !\n",
                        (devpriv->dma) ? "DMA" :
                        (devpriv->usefifo) ? "FIFO" : "IRQ",
                        chan, expected_chan);
                s->async->events |= COMEDI_CB_ERROR;
                return false;
        }

        comedi_buf_write_samples(s, &val, 1);

        devpriv->act_chanlist_pos++;
        if (devpriv->act_chanlist_pos >= devpriv->act_chanlist_len)
                devpriv->act_chanlist_pos = 0;

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

        return true;
}

static void pcl818_handle_eoc(struct comedi_device *dev,
                              struct comedi_subdevice *s)
{
        unsigned int chan;
        unsigned int val;

        if (pcl818_ai_eoc(dev, s, NULL, 0)) {
                dev_err(dev->class_dev, "A/D mode1/3 IRQ without DRDY!\n");
                s->async->events |= COMEDI_CB_ERROR;
                return;
        }

        val = pcl818_ai_get_sample(dev, s, &chan);
        pcl818_ai_write_sample(dev, s, chan, val);
}

static void pcl818_handle_dma(struct comedi_device *dev,
                              struct comedi_subdevice *s)
{
        struct pcl818_private *devpriv = dev->private;
        struct comedi_isadma *dma = devpriv->dma;
        struct comedi_isadma_desc *desc = &dma->desc[dma->cur_dma];
        unsigned short *ptr = desc->virt_addr;
        unsigned int nsamples = comedi_bytes_to_samples(s, desc->size);
        unsigned int chan;
        unsigned int val;
        int i;

        /* restart dma with the next buffer */
        dma->cur_dma = 1 - dma->cur_dma;
        pcl818_ai_setup_dma(dev, s, nsamples);

        for (i = 0; i < nsamples; i++) {
                val = ptr[i];
                chan = val & 0xf;
                val = (val >> 4) & s->maxdata;
                if (!pcl818_ai_write_sample(dev, s, chan, val))
                        break;
        }
}

static void pcl818_handle_fifo(struct comedi_device *dev,
                               struct comedi_subdevice *s)
{
        unsigned int status;
        unsigned int chan;
        unsigned int val;
        int i, len;

        status = inb(dev->iobase + PCL818_FI_STATUS);

        if (status & 4) {
                dev_err(dev->class_dev, "A/D mode1/3 FIFO overflow!\n");
                s->async->events |= COMEDI_CB_ERROR;
                return;
        }

        if (status & 1) {
                dev_err(dev->class_dev,
                        "A/D mode1/3 FIFO interrupt without data!\n");
                s->async->events |= COMEDI_CB_ERROR;
                return;
        }

        if (status & 2)
                len = 512;
        else
                len = 0;

        for (i = 0; i < len; i++) {
                val = pcl818_ai_get_fifo_sample(dev, s, &chan);
                if (!pcl818_ai_write_sample(dev, s, chan, val))
                        break;
        }
}

static irqreturn_t pcl818_interrupt(int irq, void *d)
{
        struct comedi_device *dev = d;
        struct pcl818_private *devpriv = dev->private;
        struct comedi_subdevice *s = dev->read_subdev;
        struct comedi_cmd *cmd = &s->async->cmd;

        if (!dev->attached || !devpriv->ai_cmd_running) {
                pcl818_ai_clear_eoc(dev);
                return IRQ_HANDLED;
        }

        if (devpriv->ai_cmd_canceled) {
                /*
                 * The cleanup from ai_cancel() has been delayed
                 * until now because the card doesn't seem to like
                 * being reprogrammed while a DMA transfer is in
                 * progress.
                 */
                s->async->scans_done = cmd->stop_arg;
                s->cancel(dev, s);
                return IRQ_HANDLED;
        }

        if (devpriv->dma)
                pcl818_handle_dma(dev, s);
        else if (devpriv->usefifo)
                pcl818_handle_fifo(dev, s);
        else
                pcl818_handle_eoc(dev, s);

        pcl818_ai_clear_eoc(dev);

        comedi_handle_events(dev, s);
        return IRQ_HANDLED;
}

static int check_channel_list(struct comedi_device *dev,
                              struct comedi_subdevice *s,
                              unsigned int *chanlist, unsigned int n_chan)
{
        unsigned int chansegment[16];
        unsigned int i, nowmustbechan, seglen, segpos;

        /* correct channel and range number check itself comedi/range.c */
        if (n_chan < 1) {
                dev_err(dev->class_dev, "range/channel list is empty!\n");
                return 0;
        }

        if (n_chan > 1) {
                /*  first channel is every time ok */
                chansegment[0] = chanlist[0];
                /*  build part of chanlist */
                for (i = 1, seglen = 1; i < n_chan; i++, seglen++) {
                        /* we detect loop, this must by finish */

                        if (chanlist[0] == chanlist[i])
                                break;
                        nowmustbechan =
                            (CR_CHAN(chansegment[i - 1]) + 1) % s->n_chan;
                        if (nowmustbechan != CR_CHAN(chanlist[i])) {
                                /*  channel list isn't continuous :-( */
                                dev_dbg(dev->class_dev,
                                        "channel list must be continuous! chanlist[%i]=%d but must be %d or %d!\n",
                                        i, CR_CHAN(chanlist[i]), nowmustbechan,
                                        CR_CHAN(chanlist[0]));
                                return 0;
                        }
                        /*  well, this is next correct channel in list */
                        chansegment[i] = chanlist[i];
                }

                /*  check whole chanlist */
                for (i = 0, segpos = 0; i < n_chan; i++) {
                        if (chanlist[i] != chansegment[i % seglen]) {
                                dev_dbg(dev->class_dev,
                                        "bad channel or range number! chanlist[%i]=%d,%d,%d and not %d,%d,%d!\n",
                                        i, CR_CHAN(chansegment[i]),
                                        CR_RANGE(chansegment[i]),
                                        CR_AREF(chansegment[i]),
                                        CR_CHAN(chanlist[i % seglen]),
                                        CR_RANGE(chanlist[i % seglen]),
                                        CR_AREF(chansegment[i % seglen]));
                                return 0;       /*  chan/gain list is strange */
                        }
                }
        } else {
                seglen = 1;
        }
        return seglen;
}

static int check_single_ended(unsigned int port)
{
        if (inb(port + PCL818_STATUS_REG) & PCL818_STATUS_MUX)
                return 1;
        return 0;
}

static int ai_cmdtest(struct comedi_device *dev, struct comedi_subdevice *s,
                      struct comedi_cmd *cmd)
{
        const struct pcl818_board *board = dev->board_ptr;
        int err = 0;

        /* 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_FOLLOW);
        err |= comedi_check_trigger_src(&cmd->convert_src,
                                        TRIG_TIMER | TRIG_EXT);
        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->convert_src);
        err |= comedi_check_trigger_is_unique(cmd->stop_src);

        /* Step 2b : and mutually compatible */

        if (err)
                return 2;

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

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

        if (cmd->convert_src == TRIG_TIMER) {
                err |= comedi_check_trigger_arg_min(&cmd->convert_arg,
                                                    board->ns_min);
        } else {        /* TRIG_EXT */
                err |= comedi_check_trigger_arg_is(&cmd->convert_arg, 0);
        }

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

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

        if (err)
                return 3;

        /* step 4: fix up any arguments */

        if (cmd->convert_src == TRIG_TIMER) {
                unsigned int arg = cmd->convert_arg;

                comedi_8254_cascade_ns_to_timer(dev->pacer, &arg, cmd->flags);
                err |= comedi_check_trigger_arg_is(&cmd->convert_arg, arg);
        }

        if (err)
                return 4;

        /* step 5: complain about special chanlist considerations */

        if (cmd->chanlist) {
                if (!check_channel_list(dev, s, cmd->chanlist,
                                        cmd->chanlist_len))
                        return 5;       /*  incorrect channels list */
        }

        return 0;
}

static int pcl818_ai_cmd(struct comedi_device *dev,
                         struct comedi_subdevice *s)
{
        struct pcl818_private *devpriv = dev->private;
        struct comedi_isadma *dma = devpriv->dma;
        struct comedi_cmd *cmd = &s->async->cmd;
        unsigned int ctrl = 0;
        unsigned int seglen;

        if (devpriv->ai_cmd_running)
                return -EBUSY;

        seglen = check_channel_list(dev, s, cmd->chanlist, cmd->chanlist_len);
        if (seglen < 1)
                return -EINVAL;
        pcl818_ai_setup_chanlist(dev, cmd->chanlist, seglen);

        devpriv->ai_cmd_running = 1;
        devpriv->ai_cmd_canceled = 0;
        devpriv->act_chanlist_pos = 0;

        if (cmd->convert_src == TRIG_TIMER)
                ctrl |= PCL818_CTRL_PACER_TRIG;
        else
                ctrl |= PCL818_CTRL_EXT_TRIG;

        outb(PCL818_CNTENABLE_PACER_ENA, dev->iobase + PCL818_CNTENABLE_REG);

        if (dma) {
                /* setup and enable dma for the first buffer */
                dma->cur_dma = 0;
                pcl818_ai_setup_dma(dev, s, 0);

                ctrl |= PCL818_CTRL_INTE | PCL818_CTRL_IRQ(dev->irq) |
                        PCL818_CTRL_DMAE;
        } else if (devpriv->usefifo) {
                /* enable FIFO */
                outb(1, dev->iobase + PCL818_FI_ENABLE);
        } else {
                ctrl |= PCL818_CTRL_INTE | PCL818_CTRL_IRQ(dev->irq);
        }
        outb(ctrl, dev->iobase + PCL818_CTRL_REG);

        if (cmd->convert_src == TRIG_TIMER) {
                comedi_8254_update_divisors(dev->pacer);
                comedi_8254_pacer_enable(dev->pacer, 1, 2, true);
        }

        return 0;
}

static int pcl818_ai_cancel(struct comedi_device *dev,
                            struct comedi_subdevice *s)
{
        struct pcl818_private *devpriv = dev->private;
        struct comedi_isadma *dma = devpriv->dma;
        struct comedi_cmd *cmd = &s->async->cmd;

        if (!devpriv->ai_cmd_running)
                return 0;

        if (dma) {
                if (cmd->stop_src == TRIG_NONE ||
                    (cmd->stop_src == TRIG_COUNT &&
                     s->async->scans_done < cmd->stop_arg)) {
                        if (!devpriv->ai_cmd_canceled) {
                                /*
                                * Wait for running dma transfer to end,
                                * do cleanup in interrupt.
                                */
                                devpriv->ai_cmd_canceled = 1;
                                return 0;
                        }
                }
                comedi_isadma_disable(dma->chan);
        }

        outb(PCL818_CTRL_DISABLE_TRIG, dev->iobase + PCL818_CTRL_REG);
        comedi_8254_pacer_enable(dev->pacer, 1, 2, false);
        pcl818_ai_clear_eoc(dev);

        if (devpriv->usefifo) { /*  FIFO shutdown */
                outb(0, dev->iobase + PCL818_FI_INTCLR);
                outb(0, dev->iobase + PCL818_FI_FLUSH);
                outb(0, dev->iobase + PCL818_FI_ENABLE);
        }
        devpriv->ai_cmd_running = 0;
        devpriv->ai_cmd_canceled = 0;

        return 0;
}

static int pcl818_ai_insn_read(struct comedi_device *dev,
                               struct comedi_subdevice *s,
                               struct comedi_insn *insn,
                               unsigned int *data)
{
        unsigned int chan = CR_CHAN(insn->chanspec);
        unsigned int range = CR_RANGE(insn->chanspec);
        int ret = 0;
        int i;

        outb(PCL818_CTRL_SOFT_TRIG, dev->iobase + PCL818_CTRL_REG);

        pcl818_ai_set_chan_range(dev, chan, range);
        pcl818_ai_set_chan_scan(dev, chan, chan);

        for (i = 0; i < insn->n; i++) {
                pcl818_ai_clear_eoc(dev);
                pcl818_ai_soft_trig(dev);

                ret = comedi_timeout(dev, s, insn, pcl818_ai_eoc, 0);
                if (ret)
                        break;

                data[i] = pcl818_ai_get_sample(dev, s, NULL);
        }
        pcl818_ai_clear_eoc(dev);

        return ret ? ret : insn->n;
}

static int pcl818_ao_insn_write(struct comedi_device *dev,
                                struct comedi_subdevice *s,
                                struct comedi_insn *insn,
                                unsigned int *data)
{
        unsigned int chan = CR_CHAN(insn->chanspec);
        unsigned int val = s->readback[chan];
        int i;

        for (i = 0; i < insn->n; i++) {
                val = data[i];
                outb((val & 0x000f) << 4,
                     dev->iobase + PCL818_AO_LSB_REG(chan));
                outb((val & 0x0ff0) >> 4,
                     dev->iobase + PCL818_AO_MSB_REG(chan));
        }
        s->readback[chan] = val;

        return insn->n;
}

static int pcl818_di_insn_bits(struct comedi_device *dev,
                               struct comedi_subdevice *s,
                               struct comedi_insn *insn,
                               unsigned int *data)
{
        data[1] = inb(dev->iobase + PCL818_DO_DI_LSB_REG) |
                  (inb(dev->iobase + PCL818_DO_DI_MSB_REG) << 8);

        return insn->n;
}

static int pcl818_do_insn_bits(struct comedi_device *dev,
                               struct comedi_subdevice *s,
                               struct comedi_insn *insn,
                               unsigned int *data)
{
        if (comedi_dio_update_state(s, data)) {
                outb(s->state & 0xff, dev->iobase + PCL818_DO_DI_LSB_REG);
                outb((s->state >> 8), dev->iobase + PCL818_DO_DI_MSB_REG);
        }

        data[1] = s->state;

        return insn->n;
}

static void pcl818_reset(struct comedi_device *dev)
{
        const struct pcl818_board *board = dev->board_ptr;
        unsigned int chan;

        /* flush and disable the FIFO */
        if (board->has_fifo) {
                outb(0, dev->iobase + PCL818_FI_INTCLR);
                outb(0, dev->iobase + PCL818_FI_FLUSH);
                outb(0, dev->iobase + PCL818_FI_ENABLE);
        }

        /* disable analog input trigger */
        outb(PCL818_CTRL_DISABLE_TRIG, dev->iobase + PCL818_CTRL_REG);
        pcl818_ai_clear_eoc(dev);

        pcl818_ai_set_chan_range(dev, 0, 0);

        /* stop pacer */
        outb(PCL818_CNTENABLE_PACER_ENA, dev->iobase + PCL818_CNTENABLE_REG);

        /* set analog output channels to 0V */
        for (chan = 0; chan < board->n_aochan; chan++) {
                outb(0, dev->iobase + PCL818_AO_LSB_REG(chan));
                outb(0, dev->iobase + PCL818_AO_MSB_REG(chan));
        }

        /* set all digital outputs low */
        outb(0, dev->iobase + PCL818_DO_DI_MSB_REG);
        outb(0, dev->iobase + PCL818_DO_DI_LSB_REG);
}

static void pcl818_set_ai_range_table(struct comedi_device *dev,
                                      struct comedi_subdevice *s,
                                      struct comedi_devconfig *it)
{
        const struct pcl818_board *board = dev->board_ptr;

        /* default to the range table from the boardinfo */
        s->range_table = board->ai_range_type;

        /* now check the user config option based on the boardtype */
        if (board->is_818) {
                if (it->options[4] == 1 || it->options[4] == 10) {
                        /* secondary range list jumper selectable */
                        s->range_table = &range_pcl818l_h_ai;
                }
        } else {
                switch (it->options[4]) {
                case 0:
                        s->range_table = &range_bipolar10;
                        break;
                case 1:
                        s->range_table = &range_bipolar5;
                        break;
                case 2:
                        s->range_table = &range_bipolar2_5;
                        break;
                case 3:
                        s->range_table = &range718_bipolar1;
                        break;
                case 4:
                        s->range_table = &range718_bipolar0_5;
                        break;
                case 6:
                        s->range_table = &range_unipolar10;
                        break;
                case 7:
                        s->range_table = &range_unipolar5;
                        break;
                case 8:
                        s->range_table = &range718_unipolar2;
                        break;
                case 9:
                        s->range_table = &range718_unipolar1;
                        break;
                default:
                        s->range_table = &range_unknown;
                        break;
                }
        }
}

static void pcl818_alloc_dma(struct comedi_device *dev, unsigned int dma_chan)
{
        struct pcl818_private *devpriv = dev->private;

        /* only DMA channels 3 and 1 are valid */
        if (!(dma_chan == 3 || dma_chan == 1))
                return;

        /* DMA uses two 16K buffers */
        devpriv->dma = comedi_isadma_alloc(dev, 2, dma_chan, dma_chan,
                                           PAGE_SIZE * 4, COMEDI_ISADMA_READ);
}

static void pcl818_free_dma(struct comedi_device *dev)
{
        struct pcl818_private *devpriv = dev->private;

        if (devpriv)
                comedi_isadma_free(devpriv->dma);
}

static int pcl818_attach(struct comedi_device *dev, struct comedi_devconfig *it)
{
        const struct pcl818_board *board = dev->board_ptr;
        struct pcl818_private *devpriv;
        struct comedi_subdevice *s;
        unsigned int osc_base;
        int ret;

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

        ret = comedi_request_region(dev, it->options[0],
                                    board->has_fifo ? 0x20 : 0x10);
        if (ret)
                return ret;

        /* we can use IRQ 2-7 for async command support */
        if (it->options[1] >= 2 && it->options[1] <= 7) {
                ret = request_irq(it->options[1], pcl818_interrupt, 0,
                                  dev->board_name, dev);
                if (ret == 0)
                        dev->irq = it->options[1];
        }

        /* should we use the FIFO? */
        if (dev->irq && board->has_fifo && it->options[2] == -1)
                devpriv->usefifo = 1;

        /* we need an IRQ to do DMA on channel 3 or 1 */
        if (dev->irq && board->has_dma)
                pcl818_alloc_dma(dev, it->options[2]);

        /* use 1MHz or 10MHz oscilator */
        if ((it->options[3] == 0) || (it->options[3] == 10))
                osc_base = I8254_OSC_BASE_10MHZ;
        else
                osc_base = I8254_OSC_BASE_1MHZ;

        dev->pacer = comedi_8254_init(dev->iobase + PCL818_TIMER_BASE,
                                      osc_base, I8254_IO8, 0);
        if (!dev->pacer)
                return -ENOMEM;

        /* max sampling speed */
        devpriv->ns_min = board->ns_min;
        if (!board->is_818) {
                /* extended PCL718 to 100kHz DAC */
                if ((it->options[6] == 1) || (it->options[6] == 100))
                        devpriv->ns_min = 10000;
        }

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

        s = &dev->subdevices[0];
        s->type         = COMEDI_SUBD_AI;
        s->subdev_flags = SDF_READABLE;
        if (check_single_ended(dev->iobase)) {
                s->n_chan       = 16;
                s->subdev_flags |= SDF_COMMON | SDF_GROUND;
        } else {
                s->n_chan       = 8;
                s->subdev_flags |= SDF_DIFF;
        }
        s->maxdata      = 0x0fff;

        pcl818_set_ai_range_table(dev, s, it);

        s->insn_read    = pcl818_ai_insn_read;
        if (dev->irq) {
                dev->read_subdev = s;
                s->subdev_flags |= SDF_CMD_READ;
                s->len_chanlist = s->n_chan;
                s->do_cmdtest   = ai_cmdtest;
                s->do_cmd       = pcl818_ai_cmd;
                s->cancel       = pcl818_ai_cancel;
        }

        /* Analog Output subdevice */
        s = &dev->subdevices[1];
        if (board->n_aochan) {
                s->type         = COMEDI_SUBD_AO;
                s->subdev_flags = SDF_WRITABLE | SDF_GROUND;
                s->n_chan       = board->n_aochan;
                s->maxdata      = 0x0fff;
                s->range_table  = &range_unipolar5;
                if (board->is_818) {
                        if ((it->options[4] == 1) || (it->options[4] == 10))
                                s->range_table = &range_unipolar10;
                        if (it->options[4] == 2)
                                s->range_table = &range_unknown;
                } else {
                        if ((it->options[5] == 1) || (it->options[5] == 10))
                                s->range_table = &range_unipolar10;
                        if (it->options[5] == 2)
                                s->range_table = &range_unknown;
                }
                s->insn_write   = pcl818_ao_insn_write;

                ret = comedi_alloc_subdev_readback(s);
                if (ret)
                        return ret;
        } else {
                s->type         = COMEDI_SUBD_UNUSED;
        }

        /* Digital Input subdevice */
        s = &dev->subdevices[2];
        s->type         = COMEDI_SUBD_DI;
        s->subdev_flags = SDF_READABLE;
        s->n_chan       = 16;
        s->maxdata      = 1;
        s->range_table  = &range_digital;
        s->insn_bits    = pcl818_di_insn_bits;

        /* Digital Output subdevice */
        s = &dev->subdevices[3];
        s->type         = COMEDI_SUBD_DO;
        s->subdev_flags = SDF_WRITABLE;
        s->n_chan       = 16;
        s->maxdata      = 1;
        s->range_table  = &range_digital;
        s->insn_bits    = pcl818_do_insn_bits;

        pcl818_reset(dev);

        return 0;
}

static void pcl818_detach(struct comedi_device *dev)
{
        struct pcl818_private *devpriv = dev->private;

        if (devpriv) {
                pcl818_ai_cancel(dev, dev->read_subdev);
                pcl818_reset(dev);
        }
        pcl818_free_dma(dev);
        comedi_legacy_detach(dev);
}

static struct comedi_driver pcl818_driver = {
        .driver_name    = "pcl818",
        .module         = THIS_MODULE,
        .attach         = pcl818_attach,
        .detach         = pcl818_detach,
        .board_name     = &boardtypes[0].name,
        .num_names      = ARRAY_SIZE(boardtypes),
        .offset         = sizeof(struct pcl818_board),
};
module_comedi_driver(pcl818_driver);

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