// SPDX-License-Identifier: GPL-2.0
/*
 * comedi/drivers/pcl812.c
 *
 * Author: Michal Dobes <dobes@tesnet.cz>
 *
 * hardware driver for Advantech cards
 *  card:   PCL-812, PCL-812PG, PCL-813, PCL-813B
 *  driver: pcl812,  pcl812pg,  pcl813,  pcl813b
 * and for ADlink cards
 *  card:   ACL-8112DG, ACL-8112HG, ACL-8112PG, ACL-8113, ACL-8216
 *  driver: acl8112dg,  acl8112hg,  acl8112pg,  acl8113,  acl8216
 * and for ICP DAS cards
 *  card:   ISO-813, A-821PGH, A-821PGL, A-821PGL-NDA, A-822PGH, A-822PGL,
 *  driver: iso813,  a821pgh,  a-821pgl, a-821pglnda,  a822pgh,  a822pgl,
 *  card:   A-823PGH, A-823PGL, A-826PG
 * driver:  a823pgh,  a823pgl,  a826pg
 */

/*
 * Driver: pcl812
 * Description: Advantech PCL-812/PG, PCL-813/B,
 *           ADLink ACL-8112DG/HG/PG, ACL-8113, ACL-8216,
 *           ICP DAS A-821PGH/PGL/PGL-NDA, A-822PGH/PGL, A-823PGH/PGL, A-826PG,
 *           ICP DAS ISO-813
 * Author: Michal Dobes <dobes@tesnet.cz>
 * Devices: [Advantech] PCL-812 (pcl812), PCL-812PG (pcl812pg),
 *      PCL-813 (pcl813), PCL-813B (pcl813b), [ADLink] ACL-8112DG (acl8112dg),
 *      ACL-8112HG (acl8112hg), ACL-8113 (acl-8113), ACL-8216 (acl8216),
 *      [ICP] ISO-813 (iso813), A-821PGH (a821pgh), A-821PGL (a821pgl),
 *      A-821PGL-NDA (a821pclnda), A-822PGH (a822pgh), A-822PGL (a822pgl),
 *      A-823PGH (a823pgh), A-823PGL (a823pgl), A-826PG (a826pg)
 * Updated: Mon, 06 Aug 2007 12:03:15 +0100
 * Status: works (I hope. My board fire up under my hands
 *             and I cann't test all features.)
 *
 * This driver supports insn and cmd interfaces. Some boards support only insn
 * because their hardware don't allow more (PCL-813/B, ACL-8113, ISO-813).
 * Data transfer over DMA is supported only when you measure only one
 * channel, this is too hardware limitation of these boards.
 *
 * Options for PCL-812:
 *   [0] - IO Base
 *   [1] - IRQ  (0=disable, 2, 3, 4, 5, 6, 7; 10, 11, 12, 14, 15)
 *   [2] - DMA  (0=disable, 1, 3)
 *   [3] - 0=trigger source is internal 8253 with 2MHz clock
 *         1=trigger source is external
 *   [4] - 0=A/D input range is +/-10V
 *         1=A/D input range is +/-5V
 *         2=A/D input range is +/-2.5V
 *         3=A/D input range is +/-1.25V
 *         4=A/D input range is +/-0.625V
 *         5=A/D input range is +/-0.3125V
 *   [5] - 0=D/A outputs 0-5V  (internal reference -5V)
 *         1=D/A outputs 0-10V (internal reference -10V)
 *         2=D/A outputs unknown (external reference)
 *
 * Options for PCL-812PG, ACL-8112PG:
 *   [0] - IO Base
 *   [1] - IRQ  (0=disable, 2, 3, 4, 5, 6, 7; 10, 11, 12, 14, 15)
 *   [2] - DMA  (0=disable, 1, 3)
 *   [3] - 0=trigger source is internal 8253 with 2MHz clock
 *         1=trigger source is external
 *   [4] - 0=A/D have max +/-5V input
 *         1=A/D have max +/-10V input
 *   [5] - 0=D/A outputs 0-5V  (internal reference -5V)
 *         1=D/A outputs 0-10V (internal reference -10V)
 *         2=D/A outputs unknown (external reference)
 *
 * Options for ACL-8112DG/HG, A-822PGL/PGH, A-823PGL/PGH, ACL-8216, A-826PG:
 *   [0] - IO Base
 *   [1] - IRQ  (0=disable, 2, 3, 4, 5, 6, 7; 10, 11, 12, 14, 15)
 *   [2] - DMA  (0=disable, 1, 3)
 *   [3] - 0=trigger source is internal 8253 with 2MHz clock
 *         1=trigger source is external
 *   [4] - 0=A/D channels are S.E.
 *         1=A/D channels are DIFF
 *   [5] - 0=D/A outputs 0-5V  (internal reference -5V)
 *         1=D/A outputs 0-10V (internal reference -10V)
 *         2=D/A outputs unknown (external reference)
 *
 * Options for A-821PGL/PGH:
 *   [0] - IO Base
 *   [1] - IRQ  (0=disable, 2, 3, 4, 5, 6, 7)
 *   [2] - 0=A/D channels are S.E.
 *         1=A/D channels are DIFF
 *   [3] - 0=D/A output 0-5V  (internal reference -5V)
 *         1=D/A output 0-10V (internal reference -10V)
 *
 * Options for A-821PGL-NDA:
 *   [0] - IO Base
 *   [1] - IRQ  (0=disable, 2, 3, 4, 5, 6, 7)
 *   [2] - 0=A/D channels are S.E.
 *         1=A/D channels are DIFF
 *
 * Options for PCL-813:
 *   [0] - IO Base
 *
 * Options for PCL-813B:
 *   [0] - IO Base
 *   [1] - 0= bipolar inputs
 *         1= unipolar inputs
 *
 * Options for ACL-8113, ISO-813:
 *   [0] - IO Base
 *   [1] - 0= 10V bipolar inputs
 *         1= 10V unipolar inputs
 *         2= 20V bipolar inputs
 *         3= 20V unipolar inputs
 */

#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/gfp.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/comedi/comedidev.h>
#include <linux/comedi/comedi_8254.h>
#include <linux/comedi/comedi_isadma.h>

/*
 * Register I/O map
 */
#define PCL812_TIMER_BASE                       0x00
#define PCL812_AI_LSB_REG                       0x04
#define PCL812_AI_MSB_REG                       0x05
#define PCL812_AI_MSB_DRDY                      BIT(4)
#define PCL812_AO_LSB_REG(x)                    (0x04 + ((x) * 2))
#define PCL812_AO_MSB_REG(x)                    (0x05 + ((x) * 2))
#define PCL812_DI_LSB_REG                       0x06
#define PCL812_DI_MSB_REG                       0x07
#define PCL812_STATUS_REG                       0x08
#define PCL812_STATUS_DRDY                      BIT(5)
#define PCL812_RANGE_REG                        0x09
#define PCL812_MUX_REG                          0x0a
#define PCL812_MUX_CHAN(x)                      ((x) << 0)
#define PCL812_MUX_CS0                          BIT(4)
#define PCL812_MUX_CS1                          BIT(5)
#define PCL812_CTRL_REG                         0x0b
#define PCL812_CTRL_TRIG(x)                     (((x) & 0x7) << 0)
#define PCL812_CTRL_DISABLE_TRIG                PCL812_CTRL_TRIG(0)
#define PCL812_CTRL_SOFT_TRIG                   PCL812_CTRL_TRIG(1)
#define PCL812_CTRL_PACER_DMA_TRIG              PCL812_CTRL_TRIG(2)
#define PCL812_CTRL_PACER_EOC_TRIG              PCL812_CTRL_TRIG(6)
#define PCL812_SOFTTRIG_REG                     0x0c
#define PCL812_DO_LSB_REG                       0x0d
#define PCL812_DO_MSB_REG                       0x0e

#define MAX_CHANLIST_LEN    256 /* length of scan list */

static const struct comedi_lrange range_pcl812pg_ai = {
        5, {
                BIP_RANGE(5),
                BIP_RANGE(2.5),
                BIP_RANGE(1.25),
                BIP_RANGE(0.625),
                BIP_RANGE(0.3125)
        }
};

static const struct comedi_lrange range_pcl812pg2_ai = {
        5, {
                BIP_RANGE(10),
                BIP_RANGE(5),
                BIP_RANGE(2.5),
                BIP_RANGE(1.25),
                BIP_RANGE(0.625)
        }
};

static const struct comedi_lrange range812_bipolar1_25 = {
        1, {
                BIP_RANGE(1.25)
        }
};

static const struct comedi_lrange range812_bipolar0_625 = {
        1, {
                BIP_RANGE(0.625)
        }
};

static const struct comedi_lrange range812_bipolar0_3125 = {
        1, {
                BIP_RANGE(0.3125)
        }
};

static const struct comedi_lrange range_pcl813b_ai = {
        4, {
                BIP_RANGE(5),
                BIP_RANGE(2.5),
                BIP_RANGE(1.25),
                BIP_RANGE(0.625)
        }
};

static const struct comedi_lrange range_pcl813b2_ai = {
        4, {
                UNI_RANGE(10),
                UNI_RANGE(5),
                UNI_RANGE(2.5),
                UNI_RANGE(1.25)
        }
};

static const struct comedi_lrange range_iso813_1_ai = {
        5, {
                BIP_RANGE(5),
                BIP_RANGE(2.5),
                BIP_RANGE(1.25),
                BIP_RANGE(0.625),
                BIP_RANGE(0.3125)
        }
};

static const struct comedi_lrange range_iso813_1_2_ai = {
        5, {
                UNI_RANGE(10),
                UNI_RANGE(5),
                UNI_RANGE(2.5),
                UNI_RANGE(1.25),
                UNI_RANGE(0.625)
        }
};

static const struct comedi_lrange range_iso813_2_ai = {
        4, {
                BIP_RANGE(5),
                BIP_RANGE(2.5),
                BIP_RANGE(1.25),
                BIP_RANGE(0.625)
        }
};

static const struct comedi_lrange range_iso813_2_2_ai = {
        4, {
                UNI_RANGE(10),
                UNI_RANGE(5),
                UNI_RANGE(2.5),
                UNI_RANGE(1.25)
        }
};

static const struct comedi_lrange range_acl8113_1_ai = {
        4, {
                BIP_RANGE(5),
                BIP_RANGE(2.5),
                BIP_RANGE(1.25),
                BIP_RANGE(0.625)
        }
};

static const struct comedi_lrange range_acl8113_1_2_ai = {
        4, {
                UNI_RANGE(10),
                UNI_RANGE(5),
                UNI_RANGE(2.5),
                UNI_RANGE(1.25)
        }
};

static const struct comedi_lrange range_acl8113_2_ai = {
        3, {
                BIP_RANGE(5),
                BIP_RANGE(2.5),
                BIP_RANGE(1.25)
        }
};

static const struct comedi_lrange range_acl8113_2_2_ai = {
        3, {
                UNI_RANGE(10),
                UNI_RANGE(5),
                UNI_RANGE(2.5)
        }
};

static const struct comedi_lrange range_acl8112dg_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_acl8112hg_ai = {
        12, {
                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_a821pgh_ai = {
        4, {
                BIP_RANGE(5),
                BIP_RANGE(0.5),
                BIP_RANGE(0.05),
                BIP_RANGE(0.005)
        }
};

enum pcl812_boardtype {
        BOARD_PCL812PG  = 0,    /* and ACL-8112PG */
        BOARD_PCL813B   = 1,
        BOARD_PCL812    = 2,
        BOARD_PCL813    = 3,
        BOARD_ISO813    = 5,
        BOARD_ACL8113   = 6,
        BOARD_ACL8112   = 7,    /* ACL-8112DG/HG, A-822PGL/PGH, A-823PGL/PGH */
        BOARD_ACL8216   = 8,    /* and ICP DAS A-826PG */
        BOARD_A821      = 9,    /* PGH, PGL, PGL/NDA versions */
};

struct pcl812_board {
        const char *name;
        enum pcl812_boardtype board_type;
        unsigned short min_io_start;
        int n_aichan;
        int n_aochan;
        unsigned int ai_ns_min;
        const struct comedi_lrange *rangelist_ai;
        unsigned int irq_bits;
        unsigned int has_dma:1;
        unsigned int has_16bit_ai:1;
        unsigned int has_mpc508_mux:1;
        unsigned int has_dio:1;
};

static const struct pcl812_board boardtypes[] = {
        {
                .name           = "pcl812",
                .board_type     = BOARD_PCL812,
                .min_io_start   = 0,
                .n_aichan       = 16,
                .n_aochan       = 2,
                .ai_ns_min      = 33000,
                .rangelist_ai   = &range_bipolar10,
                .irq_bits       = 0xdcfc,
                .has_dma        = 1,
                .has_dio        = 1,
        }, {
                .name           = "pcl812pg",
                .min_io_start   = 0,
                .board_type     = BOARD_PCL812PG,
                .n_aichan       = 16,
                .n_aochan       = 2,
                .ai_ns_min      = 33000,
                .rangelist_ai   = &range_pcl812pg_ai,
                .irq_bits       = 0xdcfc,
                .has_dma        = 1,
                .has_dio        = 1,
        }, {
                .name           = "acl8112pg",
                .board_type     = BOARD_PCL812PG,
                .min_io_start   = 0x200,
                .n_aichan       = 16,
                .n_aochan       = 2,
                .ai_ns_min      = 10000,
                .rangelist_ai   = &range_pcl812pg_ai,
                .irq_bits       = 0xdcfc,
                .has_dma        = 1,
                .has_dio        = 1,
        }, {
                .name           = "acl8112dg",
                .board_type     = BOARD_ACL8112,
                .min_io_start   = 0x200,
                .n_aichan       = 16,   /* 8 differential */
                .n_aochan       = 2,
                .ai_ns_min      = 10000,
                .rangelist_ai   = &range_acl8112dg_ai,
                .irq_bits       = 0xdcfc,
                .has_dma        = 1,
                .has_mpc508_mux = 1,
                .has_dio        = 1,
        }, {
                .name           = "acl8112hg",
                .board_type     = BOARD_ACL8112,
                .min_io_start   = 0x200,
                .n_aichan       = 16,   /* 8 differential */
                .n_aochan       = 2,
                .ai_ns_min      = 10000,
                .rangelist_ai   = &range_acl8112hg_ai,
                .irq_bits       = 0xdcfc,
                .has_dma        = 1,
                .has_mpc508_mux = 1,
                .has_dio        = 1,
        }, {
                .name           = "a821pgl",
                .board_type     = BOARD_A821,
                .min_io_start   = 0,
                .n_aichan       = 16,   /* 8 differential */
                .n_aochan       = 1,
                .ai_ns_min      = 10000,
                .rangelist_ai   = &range_pcl813b_ai,
                .irq_bits       = 0x000c,
                .has_dio        = 1,
        }, {
                .name           = "a821pglnda",
                .board_type     = BOARD_A821,
                .min_io_start   = 0,
                .n_aichan       = 16,   /* 8 differential */
                .ai_ns_min      = 10000,
                .rangelist_ai   = &range_pcl813b_ai,
                .irq_bits       = 0x000c,
        }, {
                .name           = "a821pgh",
                .board_type     = BOARD_A821,
                .min_io_start   = 0,
                .n_aichan       = 16,   /* 8 differential */
                .n_aochan       = 1,
                .ai_ns_min      = 10000,
                .rangelist_ai   = &range_a821pgh_ai,
                .irq_bits       = 0x000c,
                .has_dio        = 1,
        }, {
                .name           = "a822pgl",
                .board_type     = BOARD_ACL8112,
                .min_io_start   = 0,
                .n_aichan       = 16,   /* 8 differential */
                .n_aochan       = 2,
                .ai_ns_min      = 10000,
                .rangelist_ai   = &range_acl8112dg_ai,
                .irq_bits       = 0xdcfc,
                .has_dma        = 1,
                .has_dio        = 1,
        }, {
                .name           = "a822pgh",
                .board_type     = BOARD_ACL8112,
                .min_io_start   = 0,
                .n_aichan       = 16,   /* 8 differential */
                .n_aochan       = 2,
                .ai_ns_min      = 10000,
                .rangelist_ai   = &range_acl8112hg_ai,
                .irq_bits       = 0xdcfc,
                .has_dma        = 1,
                .has_dio        = 1,
        }, {
                .name           = "a823pgl",
                .board_type     = BOARD_ACL8112,
                .min_io_start   = 0,
                .n_aichan       = 16,   /* 8 differential */
                .n_aochan       = 2,
                .ai_ns_min      = 8000,
                .rangelist_ai   = &range_acl8112dg_ai,
                .irq_bits       = 0xdcfc,
                .has_dma        = 1,
                .has_dio        = 1,
        }, {
                .name           = "a823pgh",
                .board_type     = BOARD_ACL8112,
                .min_io_start   = 0,
                .n_aichan       = 16,   /* 8 differential */
                .n_aochan       = 2,
                .ai_ns_min      = 8000,
                .rangelist_ai   = &range_acl8112hg_ai,
                .irq_bits       = 0xdcfc,
                .has_dma        = 1,
                .has_dio        = 1,
        }, {
                .name           = "pcl813",
                .board_type     = BOARD_PCL813,
                .min_io_start   = 0,
                .n_aichan       = 32,
                .rangelist_ai   = &range_pcl813b_ai,
        }, {
                .name           = "pcl813b",
                .board_type     = BOARD_PCL813B,
                .min_io_start   = 0,
                .n_aichan       = 32,
                .rangelist_ai   = &range_pcl813b_ai,
        }, {
                .name           = "acl8113",
                .board_type     = BOARD_ACL8113,
                .min_io_start   = 0x200,
                .n_aichan       = 32,
                .rangelist_ai   = &range_acl8113_1_ai,
        }, {
                .name           = "iso813",
                .board_type     = BOARD_ISO813,
                .min_io_start   = 0,
                .n_aichan       = 32,
                .rangelist_ai   = &range_iso813_1_ai,
        }, {
                .name           = "acl8216",
                .board_type     = BOARD_ACL8216,
                .min_io_start   = 0x200,
                .n_aichan       = 16,   /* 8 differential */
                .n_aochan       = 2,
                .ai_ns_min      = 10000,
                .rangelist_ai   = &range_pcl813b2_ai,
                .irq_bits       = 0xdcfc,
                .has_dma        = 1,
                .has_16bit_ai   = 1,
                .has_mpc508_mux = 1,
                .has_dio        = 1,
        }, {
                .name           = "a826pg",
                .board_type     = BOARD_ACL8216,
                .min_io_start   = 0,
                .n_aichan       = 16,   /* 8 differential */
                .n_aochan       = 2,
                .ai_ns_min      = 10000,
                .rangelist_ai   = &range_pcl813b2_ai,
                .irq_bits       = 0xdcfc,
                .has_dma        = 1,
                .has_16bit_ai   = 1,
                .has_dio        = 1,
        },
};

struct pcl812_private {
        struct comedi_isadma *dma;
        unsigned char range_correction; /* =1 we must add 1 to range number */
        unsigned int last_ai_chanspec;
        unsigned char mode_reg_int; /* stored INT number for some cards */
        unsigned int ai_poll_ptr; /* how many samples transfer poll */
        unsigned int max_812_ai_mode0_rangewait; /* settling time for gain */
        unsigned int use_diff:1;
        unsigned int use_mpc508:1;
        unsigned int use_ext_trg:1;
        unsigned int ai_dma:1;
        unsigned int ai_eos:1;
};

static void pcl812_ai_setup_dma(struct comedi_device *dev,
                                struct comedi_subdevice *s,
                                unsigned int unread_samples)
{
        struct pcl812_private *devpriv = dev->private;
        struct comedi_isadma *dma = devpriv->dma;
        struct comedi_isadma_desc *desc = &dma->desc[dma->cur_dma];
        unsigned int bytes;
        unsigned int max_samples;
        unsigned int nsamples;

        comedi_isadma_disable(dma->chan);

        /* if using EOS, adapt DMA buffer to one scan */
        bytes = devpriv->ai_eos ? comedi_bytes_per_scan(s) : desc->maxsize;
        max_samples = comedi_bytes_to_samples(s, bytes);

        /*
         * Determine dma size based on the buffer size 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 pcl812_ai_set_chan_range(struct comedi_device *dev,
                                     unsigned int chanspec, char wait)
{
        struct pcl812_private *devpriv = dev->private;
        unsigned int chan = CR_CHAN(chanspec);
        unsigned int range = CR_RANGE(chanspec);
        unsigned int mux = 0;

        if (chanspec == devpriv->last_ai_chanspec)
                return;

        devpriv->last_ai_chanspec = chanspec;

        if (devpriv->use_mpc508) {
                if (devpriv->use_diff) {
                        mux |= PCL812_MUX_CS0 | PCL812_MUX_CS1;
                } else {
                        if (chan < 8)
                                mux |= PCL812_MUX_CS0;
                        else
                                mux |= PCL812_MUX_CS1;
                }
        }

        outb(mux | PCL812_MUX_CHAN(chan), dev->iobase + PCL812_MUX_REG);
        outb(range + devpriv->range_correction, dev->iobase + PCL812_RANGE_REG);

        if (wait)
                /*
                 * XXX this depends on selected range and can be very long for
                 * some high gain ranges!
                 */
                udelay(devpriv->max_812_ai_mode0_rangewait);
}

static void pcl812_ai_clear_eoc(struct comedi_device *dev)
{
        /* writing any value clears the interrupt request */
        outb(0, dev->iobase + PCL812_STATUS_REG);
}

static void pcl812_ai_soft_trig(struct comedi_device *dev)
{
        /* writing any value triggers a software conversion */
        outb(255, dev->iobase + PCL812_SOFTTRIG_REG);
}

static unsigned int pcl812_ai_get_sample(struct comedi_device *dev,
                                         struct comedi_subdevice *s)
{
        unsigned int val;

        val = inb(dev->iobase + PCL812_AI_MSB_REG) << 8;
        val |= inb(dev->iobase + PCL812_AI_LSB_REG);

        return val & s->maxdata;
}

static int pcl812_ai_eoc(struct comedi_device *dev,
                         struct comedi_subdevice *s,
                         struct comedi_insn *insn,
                         unsigned long context)
{
        unsigned int status;

        if (s->maxdata > 0x0fff) {
                status = inb(dev->iobase + PCL812_STATUS_REG);
                if ((status & PCL812_STATUS_DRDY) == 0)
                        return 0;
        } else {
                status = inb(dev->iobase + PCL812_AI_MSB_REG);
                if ((status & PCL812_AI_MSB_DRDY) == 0)
                        return 0;
        }
        return -EBUSY;
}

static int pcl812_ai_cmdtest(struct comedi_device *dev,
                             struct comedi_subdevice *s, struct comedi_cmd *cmd)
{
        const struct pcl812_board *board = dev->board_ptr;
        struct pcl812_private *devpriv = dev->private;
        int err = 0;
        unsigned int flags;

        /* 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);

        if (devpriv->use_ext_trg)
                flags = TRIG_EXT;
        else
                flags = TRIG_TIMER;
        err |= comedi_check_trigger_src(&cmd->convert_src, flags);

        err |= comedi_check_trigger_src(&cmd->scan_end_src, TRIG_COUNT);
        err |= comedi_check_trigger_src(&cmd->stop_src, TRIG_COUNT | TRIG_NONE);

        if (err)
                return 1;

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

        err |= comedi_check_trigger_is_unique(cmd->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->ai_ns_min);
        } else {        /* TRIG_EXT */
                err |= comedi_check_trigger_arg_is(&cmd->convert_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->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;

        return 0;
}

static int pcl812_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
{
        struct pcl812_private *devpriv = dev->private;
        struct comedi_isadma *dma = devpriv->dma;
        struct comedi_cmd *cmd = &s->async->cmd;
        unsigned int ctrl = 0;
        unsigned int i;

        pcl812_ai_set_chan_range(dev, cmd->chanlist[0], 1);

        if (dma) {      /*  check if we can use DMA transfer */
                devpriv->ai_dma = 1;
                for (i = 1; i < cmd->chanlist_len; i++)
                        if (cmd->chanlist[0] != cmd->chanlist[i]) {
                                /*  we cann't use DMA :-( */
                                devpriv->ai_dma = 0;
                                break;
                        }
        } else {
                devpriv->ai_dma = 0;
        }

        devpriv->ai_poll_ptr = 0;

        /*  don't we want wake up every scan? */
        if (cmd->flags & CMDF_WAKE_EOS) {
                devpriv->ai_eos = 1;

                /*  DMA is useless for this situation */
                if (cmd->chanlist_len == 1)
                        devpriv->ai_dma = 0;
        }

        if (devpriv->ai_dma) {
                /* setup and enable dma for the first buffer */
                dma->cur_dma = 0;
                pcl812_ai_setup_dma(dev, s, 0);
        }

        switch (cmd->convert_src) {
        case TRIG_TIMER:
                comedi_8254_update_divisors(dev->pacer);
                comedi_8254_pacer_enable(dev->pacer, 1, 2, true);
                break;
        }

        if (devpriv->ai_dma)
                ctrl |= PCL812_CTRL_PACER_DMA_TRIG;
        else
                ctrl |= PCL812_CTRL_PACER_EOC_TRIG;
        outb(devpriv->mode_reg_int | ctrl, dev->iobase + PCL812_CTRL_REG);

        return 0;
}

static bool pcl812_ai_next_chan(struct comedi_device *dev,
                                struct comedi_subdevice *s)
{
        struct comedi_cmd *cmd = &s->async->cmd;

        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 pcl812_handle_eoc(struct comedi_device *dev,
                              struct comedi_subdevice *s)
{
        struct comedi_cmd *cmd = &s->async->cmd;
        unsigned int chan = s->async->cur_chan;
        unsigned int next_chan;
        unsigned short val;

        if (pcl812_ai_eoc(dev, s, NULL, 0)) {
                dev_dbg(dev->class_dev, "A/D cmd IRQ without DRDY!\n");
                s->async->events |= COMEDI_CB_ERROR;
                return;
        }

        val = pcl812_ai_get_sample(dev, s);
        comedi_buf_write_samples(s, &val, 1);

        /* Set up next channel. Added by abbotti 2010-01-20, but untested. */
        next_chan = s->async->cur_chan;
        if (cmd->chanlist[chan] != cmd->chanlist[next_chan])
                pcl812_ai_set_chan_range(dev, cmd->chanlist[next_chan], 0);

        pcl812_ai_next_chan(dev, s);
}

static void transfer_from_dma_buf(struct comedi_device *dev,
                                  struct comedi_subdevice *s,
                                  unsigned short *ptr,
                                  unsigned int bufptr, unsigned int len)
{
        unsigned int i;
        unsigned short val;

        for (i = len; i; i--) {
                val = ptr[bufptr++];
                comedi_buf_write_samples(s, &val, 1);

                if (!pcl812_ai_next_chan(dev, s))
                        break;
        }
}

static void pcl812_handle_dma(struct comedi_device *dev,
                              struct comedi_subdevice *s)
{
        struct pcl812_private *devpriv = dev->private;
        struct comedi_isadma *dma = devpriv->dma;
        struct comedi_isadma_desc *desc = &dma->desc[dma->cur_dma];
        unsigned int nsamples;
        int bufptr;

        nsamples = comedi_bytes_to_samples(s, desc->size) -
                   devpriv->ai_poll_ptr;
        bufptr = devpriv->ai_poll_ptr;
        devpriv->ai_poll_ptr = 0;

        /* restart dma with the next buffer */
        dma->cur_dma = 1 - dma->cur_dma;
        pcl812_ai_setup_dma(dev, s, nsamples);

        transfer_from_dma_buf(dev, s, desc->virt_addr, bufptr, nsamples);
}

static irqreturn_t pcl812_interrupt(int irq, void *d)
{
        struct comedi_device *dev = d;
        struct comedi_subdevice *s = dev->read_subdev;
        struct pcl812_private *devpriv = dev->private;

        if (!dev->attached) {
                pcl812_ai_clear_eoc(dev);
                return IRQ_HANDLED;
        }

        if (devpriv->ai_dma)
                pcl812_handle_dma(dev, s);
        else
                pcl812_handle_eoc(dev, s);

        pcl812_ai_clear_eoc(dev);

        comedi_handle_events(dev, s);
        return IRQ_HANDLED;
}

static int pcl812_ai_poll(struct comedi_device *dev, struct comedi_subdevice *s)
{
        struct pcl812_private *devpriv = dev->private;
        struct comedi_isadma *dma = devpriv->dma;
        struct comedi_isadma_desc *desc;
        unsigned long flags;
        unsigned int poll;
        int ret;

        /* poll is valid only for DMA transfer */
        if (!devpriv->ai_dma)
                return 0;

        spin_lock_irqsave(&dev->spinlock, flags);

        poll = comedi_isadma_poll(dma);
        poll = comedi_bytes_to_samples(s, poll);
        if (poll > devpriv->ai_poll_ptr) {
                desc = &dma->desc[dma->cur_dma];
                transfer_from_dma_buf(dev, s, desc->virt_addr,
                                      devpriv->ai_poll_ptr,
                                      poll - devpriv->ai_poll_ptr);
                /* new buffer position */
                devpriv->ai_poll_ptr = poll;

                ret = comedi_buf_n_bytes_ready(s);
        } else {
                /* no new samples */
                ret = 0;
        }

        spin_unlock_irqrestore(&dev->spinlock, flags);

        return ret;
}

static int pcl812_ai_cancel(struct comedi_device *dev,
                            struct comedi_subdevice *s)
{
        struct pcl812_private *devpriv = dev->private;

        if (devpriv->ai_dma)
                comedi_isadma_disable(devpriv->dma->chan);

        outb(devpriv->mode_reg_int | PCL812_CTRL_DISABLE_TRIG,
             dev->iobase + PCL812_CTRL_REG);
        comedi_8254_pacer_enable(dev->pacer, 1, 2, false);
        pcl812_ai_clear_eoc(dev);
        return 0;
}

static int pcl812_ai_insn_read(struct comedi_device *dev,
                               struct comedi_subdevice *s,
                               struct comedi_insn *insn,
                               unsigned int *data)
{
        struct pcl812_private *devpriv = dev->private;
        int ret = 0;
        int i;

        outb(devpriv->mode_reg_int | PCL812_CTRL_SOFT_TRIG,
             dev->iobase + PCL812_CTRL_REG);

        pcl812_ai_set_chan_range(dev, insn->chanspec, 1);

        for (i = 0; i < insn->n; i++) {
                pcl812_ai_clear_eoc(dev);
                pcl812_ai_soft_trig(dev);

                ret = comedi_timeout(dev, s, insn, pcl812_ai_eoc, 0);
                if (ret)
                        break;

                data[i] = pcl812_ai_get_sample(dev, s);
        }
        outb(devpriv->mode_reg_int | PCL812_CTRL_DISABLE_TRIG,
             dev->iobase + PCL812_CTRL_REG);
        pcl812_ai_clear_eoc(dev);

        return ret ? ret : insn->n;
}

static int pcl812_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 & 0xff, dev->iobase + PCL812_AO_LSB_REG(chan));
                outb((val >> 8) & 0x0f, dev->iobase + PCL812_AO_MSB_REG(chan));
        }
        s->readback[chan] = val;

        return insn->n;
}

static int pcl812_di_insn_bits(struct comedi_device *dev,
                               struct comedi_subdevice *s,
                               struct comedi_insn *insn,
                               unsigned int *data)
{
        data[1] = inb(dev->iobase + PCL812_DI_LSB_REG) |
                  (inb(dev->iobase + PCL812_DI_MSB_REG) << 8);

        return insn->n;
}

static int pcl812_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 + PCL812_DO_LSB_REG);
                outb((s->state >> 8), dev->iobase + PCL812_DO_MSB_REG);
        }

        data[1] = s->state;

        return insn->n;
}

static void pcl812_reset(struct comedi_device *dev)
{
        const struct pcl812_board *board = dev->board_ptr;
        struct pcl812_private *devpriv = dev->private;
        unsigned int chan;

        /* disable analog input trigger */
        outb(devpriv->mode_reg_int | PCL812_CTRL_DISABLE_TRIG,
             dev->iobase + PCL812_CTRL_REG);
        pcl812_ai_clear_eoc(dev);

        /*
         * Invalidate last_ai_chanspec then set analog input to
         * known channel/range.
         */
        devpriv->last_ai_chanspec = CR_PACK(16, 0, 0);
        pcl812_ai_set_chan_range(dev, CR_PACK(0, 0, 0), 0);

        /* set analog output channels to 0V */
        for (chan = 0; chan < board->n_aochan; chan++) {
                outb(0, dev->iobase + PCL812_AO_LSB_REG(chan));
                outb(0, dev->iobase + PCL812_AO_MSB_REG(chan));
        }

        /* set all digital outputs low */
        if (board->has_dio) {
                outb(0, dev->iobase + PCL812_DO_MSB_REG);
                outb(0, dev->iobase + PCL812_DO_LSB_REG);
        }
}

static void pcl812_set_ai_range_table(struct comedi_device *dev,
                                      struct comedi_subdevice *s,
                                      struct comedi_devconfig *it)
{
        const struct pcl812_board *board = dev->board_ptr;
        struct pcl812_private *devpriv = dev->private;

        switch (board->board_type) {
        case BOARD_PCL812PG:
                if (it->options[4] == 1)
                        s->range_table = &range_pcl812pg2_ai;
                else
                        s->range_table = board->rangelist_ai;
                break;
        case BOARD_PCL812:
                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 = &range812_bipolar1_25;
                        break;
                case 4:
                        s->range_table = &range812_bipolar0_625;
                        break;
                case 5:
                        s->range_table = &range812_bipolar0_3125;
                        break;
                default:
                        s->range_table = &range_bipolar10;
                        break;
                }
                break;
        case BOARD_PCL813B:
                if (it->options[1] == 1)
                        s->range_table = &range_pcl813b2_ai;
                else
                        s->range_table = board->rangelist_ai;
                break;
        case BOARD_ISO813:
                switch (it->options[1]) {
                case 0:
                        s->range_table = &range_iso813_1_ai;
                        break;
                case 1:
                        s->range_table = &range_iso813_1_2_ai;
                        break;
                case 2:
                        s->range_table = &range_iso813_2_ai;
                        devpriv->range_correction = 1;
                        break;
                case 3:
                        s->range_table = &range_iso813_2_2_ai;
                        devpriv->range_correction = 1;
                        break;
                default:
                        s->range_table = &range_iso813_1_ai;
                        break;
                }
                break;
        case BOARD_ACL8113:
                switch (it->options[1]) {
                case 0:
                        s->range_table = &range_acl8113_1_ai;
                        break;
                case 1:
                        s->range_table = &range_acl8113_1_2_ai;
                        break;
                case 2:
                        s->range_table = &range_acl8113_2_ai;
                        devpriv->range_correction = 1;
                        break;
                case 3:
                        s->range_table = &range_acl8113_2_2_ai;
                        devpriv->range_correction = 1;
                        break;
                default:
                        s->range_table = &range_acl8113_1_ai;
                        break;
                }
                break;
        default:
                s->range_table = board->rangelist_ai;
                break;
        }
}

static void pcl812_alloc_dma(struct comedi_device *dev, unsigned int dma_chan)
{
        struct pcl812_private *devpriv = dev->private;

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

        /* DMA uses two 8K buffers */
        devpriv->dma = comedi_isadma_alloc(dev, 2, dma_chan, dma_chan,
                                           PAGE_SIZE * 2, COMEDI_ISADMA_READ);
}

static void pcl812_free_dma(struct comedi_device *dev)
{
        struct pcl812_private *devpriv = dev->private;

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

static int pcl812_attach(struct comedi_device *dev, struct comedi_devconfig *it)
{
        const struct pcl812_board *board = dev->board_ptr;
        struct pcl812_private *devpriv;
        struct comedi_subdevice *s;
        int n_subdevices;
        int subdev;
        int ret;

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

        ret = comedi_check_request_region(dev, it->options[0], 0x10,
                                          board->min_io_start, 0x3ff, 16);
        if (ret)
                return ret;

        if (board->irq_bits) {
                dev->pacer =
                    comedi_8254_io_alloc(dev->iobase + PCL812_TIMER_BASE,
                                         I8254_OSC_BASE_2MHZ, I8254_IO8, 0);
                if (IS_ERR(dev->pacer))
                        return PTR_ERR(dev->pacer);

                if (it->options[1] > 0 && it->options[1] < 16 &&
                    (1 << it->options[1]) & board->irq_bits) {
                        ret = request_irq(it->options[1], pcl812_interrupt, 0,
                                          dev->board_name, dev);
                        if (ret == 0)
                                dev->irq = it->options[1];
                }
        }

        /* we need an IRQ to do DMA on channel 3 or 1 */
        if (dev->irq && board->has_dma)
                pcl812_alloc_dma(dev, it->options[2]);

        /* differential analog inputs? */
        switch (board->board_type) {
        case BOARD_A821:
                if (it->options[2] == 1)
                        devpriv->use_diff = 1;
                break;
        case BOARD_ACL8112:
        case BOARD_ACL8216:
                if (it->options[4] == 1)
                        devpriv->use_diff = 1;
                break;
        default:
                break;
        }

        n_subdevices = 1;               /* all boardtypes have analog inputs */
        if (board->n_aochan > 0)
                n_subdevices++;
        if (board->has_dio)
                n_subdevices += 2;

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

        subdev = 0;

        /* Analog Input subdevice */
        s = &dev->subdevices[subdev];
        s->type         = COMEDI_SUBD_AI;
        s->subdev_flags = SDF_READABLE;
        if (devpriv->use_diff) {
                s->subdev_flags |= SDF_DIFF;
                s->n_chan       = board->n_aichan / 2;
        } else {
                s->subdev_flags |= SDF_GROUND;
                s->n_chan       = board->n_aichan;
        }
        s->maxdata      = board->has_16bit_ai ? 0xffff : 0x0fff;

        pcl812_set_ai_range_table(dev, s, it);

        s->insn_read    = pcl812_ai_insn_read;

        if (dev->irq) {
                dev->read_subdev = s;
                s->subdev_flags |= SDF_CMD_READ;
                s->len_chanlist = MAX_CHANLIST_LEN;
                s->do_cmdtest   = pcl812_ai_cmdtest;
                s->do_cmd       = pcl812_ai_cmd;
                s->poll         = pcl812_ai_poll;
                s->cancel       = pcl812_ai_cancel;
        }

        devpriv->use_mpc508 = board->has_mpc508_mux;

        subdev++;

        /* analog output */
        if (board->n_aochan > 0) {
                s = &dev->subdevices[subdev];
                s->type         = COMEDI_SUBD_AO;
                s->subdev_flags = SDF_WRITABLE | SDF_GROUND;
                s->n_chan       = board->n_aochan;
                s->maxdata      = 0xfff;
                switch (board->board_type) {
                case BOARD_A821:
                        if (it->options[3] == 1)
                                s->range_table = &range_unipolar10;
                        else
                                s->range_table = &range_unipolar5;
                        break;
                case BOARD_PCL812:
                case BOARD_ACL8112:
                case BOARD_PCL812PG:
                case BOARD_ACL8216:
                        switch (it->options[5]) {
                        case 1:
                                s->range_table = &range_unipolar10;
                                break;
                        case 2:
                                s->range_table = &range_unknown;
                                break;
                        default:
                                s->range_table = &range_unipolar5;
                                break;
                        }
                        break;
                default:
                        s->range_table = &range_unipolar5;
                        break;
                }
                s->insn_write   = pcl812_ao_insn_write;

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

                subdev++;
        }

        if (board->has_dio) {
                /* Digital Input subdevice */
                s = &dev->subdevices[subdev];
                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    = pcl812_di_insn_bits;
                subdev++;

                /* Digital Output subdevice */
                s = &dev->subdevices[subdev];
                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    = pcl812_do_insn_bits;
                subdev++;
        }

        switch (board->board_type) {
        case BOARD_ACL8216:
        case BOARD_PCL812PG:
        case BOARD_PCL812:
        case BOARD_ACL8112:
                devpriv->max_812_ai_mode0_rangewait = 1;
                if (it->options[3] > 0)
                                                /*  we use external trigger */
                        devpriv->use_ext_trg = 1;
                break;
        case BOARD_A821:
                devpriv->max_812_ai_mode0_rangewait = 1;
                devpriv->mode_reg_int = (dev->irq << 4) & 0xf0;
                break;
        case BOARD_PCL813B:
        case BOARD_PCL813:
        case BOARD_ISO813:
        case BOARD_ACL8113:
                /* maybe there must by greatest timeout */
                devpriv->max_812_ai_mode0_rangewait = 5;
                break;
        }

        pcl812_reset(dev);

        return 0;
}

static void pcl812_detach(struct comedi_device *dev)
{
        pcl812_free_dma(dev);
        comedi_legacy_detach(dev);
}

static struct comedi_driver pcl812_driver = {
        .driver_name    = "pcl812",
        .module         = THIS_MODULE,
        .attach         = pcl812_attach,
        .detach         = pcl812_detach,
        .board_name     = &boardtypes[0].name,
        .num_names      = ARRAY_SIZE(boardtypes),
        .offset         = sizeof(struct pcl812_board),
};
module_comedi_driver(pcl812_driver);

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