// SPDX-License-Identifier: GPL-2.0+
/*
 * pcmmio.c
 * Driver for Winsystems PC-104 based multifunction IO board.
 *
 * COMEDI - Linux Control and Measurement Device Interface
 * Copyright (C) 2007 Calin A. Culianu <calin@ajvar.org>
 */

/*
 * Driver: pcmmio
 * Description: A driver for the PCM-MIO multifunction board
 * Devices: [Winsystems] PCM-MIO (pcmmio)
 * Author: Calin Culianu <calin@ajvar.org>
 * Updated: Wed, May 16 2007 16:21:10 -0500
 * Status: works
 *
 * A driver for the PCM-MIO multifunction board from Winsystems. This
 * is a PC-104 based I/O board. It contains four subdevices:
 *
 *      subdevice 0 - 16 channels of 16-bit AI
 *      subdevice 1 - 8 channels of 16-bit AO
 *      subdevice 2 - first 24 channels of the 48 channel of DIO
 *                      (with edge-triggered interrupt support)
 *      subdevice 3 - last 24 channels of the 48 channel DIO
 *                      (no interrupt support for this bank of channels)
 *
 * Some notes:
 *
 * Synchronous reads and writes are the only things implemented for analog
 * input and output. The hardware itself can do streaming acquisition, etc.
 *
 * Asynchronous I/O for the DIO subdevices *is* implemented, however! They
 * are basically edge-triggered interrupts for any configuration of the
 * channels in subdevice 2.
 *
 * Also note that this interrupt support is untested.
 *
 * A few words about edge-detection IRQ support (commands on DIO):
 *
 * To use edge-detection IRQ support for the DIO subdevice, pass the IRQ
 * of the board to the comedi_config command. The board IRQ is not jumpered
 * but rather configured through software, so any IRQ from 1-15 is OK.
 *
 * Due to the genericity of the comedi API, you need to create a special
 * comedi_command in order to use edge-triggered interrupts for DIO.
 *
 * Use comedi_commands with TRIG_NOW.  Your callback will be called each
 * time an edge is detected on the specified DIO line(s), and the data
 * values will be two sample_t's, which should be concatenated to form
 * one 32-bit unsigned int. This value is the mask of channels that had
 * edges detected from your channel list. Note that the bits positions
 * in the mask correspond to positions in your chanlist when you
 * specified the command and *not* channel id's!
 *
 * To set the polarity of the edge-detection interrupts pass a nonzero value
 * for either CR_RANGE or CR_AREF for edge-up polarity, or a zero
 * value for both CR_RANGE and CR_AREF if you want edge-down polarity.
 *
 * Configuration Options:
 *   [0] - I/O port base address
 *   [1] - IRQ (optional -- for edge-detect interrupt support only,
 *              leave out if you don't need this feature)
 */

#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/slab.h>
#include <linux/comedi/comedidev.h>

/*
 * Register I/O map
 */
#define PCMMIO_AI_LSB_REG                       0x00
#define PCMMIO_AI_MSB_REG                       0x01
#define PCMMIO_AI_CMD_REG                       0x02
#define PCMMIO_AI_CMD_SE                        BIT(7)
#define PCMMIO_AI_CMD_ODD_CHAN                  BIT(6)
#define PCMMIO_AI_CMD_CHAN_SEL(x)               (((x) & 0x3) << 4)
#define PCMMIO_AI_CMD_RANGE(x)                  (((x) & 0x3) << 2)
#define PCMMIO_RESOURCE_REG                     0x02
#define PCMMIO_RESOURCE_IRQ(x)                  (((x) & 0xf) << 0)
#define PCMMIO_AI_STATUS_REG                    0x03
#define PCMMIO_AI_STATUS_DATA_READY             BIT(7)
#define PCMMIO_AI_STATUS_DATA_DMA_PEND          BIT(6)
#define PCMMIO_AI_STATUS_CMD_DMA_PEND           BIT(5)
#define PCMMIO_AI_STATUS_IRQ_PEND               BIT(4)
#define PCMMIO_AI_STATUS_DATA_DRQ_ENA           BIT(2)
#define PCMMIO_AI_STATUS_REG_SEL                BIT(3)
#define PCMMIO_AI_STATUS_CMD_DRQ_ENA            BIT(1)
#define PCMMIO_AI_STATUS_IRQ_ENA                BIT(0)
#define PCMMIO_AI_RES_ENA_REG                   0x03
#define PCMMIO_AI_RES_ENA_CMD_REG_ACCESS        (0 << 3)
#define PCMMIO_AI_RES_ENA_AI_RES_ACCESS         BIT(3)
#define PCMMIO_AI_RES_ENA_DIO_RES_ACCESS        BIT(4)
#define PCMMIO_AI_2ND_ADC_OFFSET                0x04

#define PCMMIO_AO_LSB_REG                       0x08
#define PCMMIO_AO_LSB_SPAN(x)                   (((x) & 0xf) << 0)
#define PCMMIO_AO_MSB_REG                       0x09
#define PCMMIO_AO_CMD_REG                       0x0a
#define PCMMIO_AO_CMD_WR_SPAN                   (0x2 << 4)
#define PCMMIO_AO_CMD_WR_CODE                   (0x3 << 4)
#define PCMMIO_AO_CMD_UPDATE                    (0x4 << 4)
#define PCMMIO_AO_CMD_UPDATE_ALL                (0x5 << 4)
#define PCMMIO_AO_CMD_WR_SPAN_UPDATE            (0x6 << 4)
#define PCMMIO_AO_CMD_WR_CODE_UPDATE            (0x7 << 4)
#define PCMMIO_AO_CMD_WR_SPAN_UPDATE_ALL        (0x8 << 4)
#define PCMMIO_AO_CMD_WR_CODE_UPDATE_ALL        (0x9 << 4)
#define PCMMIO_AO_CMD_RD_B1_SPAN                (0xa << 4)
#define PCMMIO_AO_CMD_RD_B1_CODE                (0xb << 4)
#define PCMMIO_AO_CMD_RD_B2_SPAN                (0xc << 4)
#define PCMMIO_AO_CMD_RD_B2_CODE                (0xd << 4)
#define PCMMIO_AO_CMD_NOP                       (0xf << 4)
#define PCMMIO_AO_CMD_CHAN_SEL(x)               (((x) & 0x03) << 1)
#define PCMMIO_AO_CMD_CHAN_SEL_ALL              (0x0f << 0)
#define PCMMIO_AO_STATUS_REG                    0x0b
#define PCMMIO_AO_STATUS_DATA_READY             BIT(7)
#define PCMMIO_AO_STATUS_DATA_DMA_PEND          BIT(6)
#define PCMMIO_AO_STATUS_CMD_DMA_PEND           BIT(5)
#define PCMMIO_AO_STATUS_IRQ_PEND               BIT(4)
#define PCMMIO_AO_STATUS_DATA_DRQ_ENA           BIT(2)
#define PCMMIO_AO_STATUS_REG_SEL                BIT(3)
#define PCMMIO_AO_STATUS_CMD_DRQ_ENA            BIT(1)
#define PCMMIO_AO_STATUS_IRQ_ENA                BIT(0)
#define PCMMIO_AO_RESOURCE_ENA_REG              0x0b
#define PCMMIO_AO_2ND_DAC_OFFSET                0x04

/*
 * WinSystems WS16C48
 *
 * Offset    Page 0       Page 1       Page 2       Page 3
 * ------  -----------  -----------  -----------  -----------
 *  0x10   Port 0 I/O   Port 0 I/O   Port 0 I/O   Port 0 I/O
 *  0x11   Port 1 I/O   Port 1 I/O   Port 1 I/O   Port 1 I/O
 *  0x12   Port 2 I/O   Port 2 I/O   Port 2 I/O   Port 2 I/O
 *  0x13   Port 3 I/O   Port 3 I/O   Port 3 I/O   Port 3 I/O
 *  0x14   Port 4 I/O   Port 4 I/O   Port 4 I/O   Port 4 I/O
 *  0x15   Port 5 I/O   Port 5 I/O   Port 5 I/O   Port 5 I/O
 *  0x16   INT_PENDING  INT_PENDING  INT_PENDING  INT_PENDING
 *  0x17    Page/Lock    Page/Lock    Page/Lock    Page/Lock
 *  0x18       N/A         POL_0       ENAB_0       INT_ID0
 *  0x19       N/A         POL_1       ENAB_1       INT_ID1
 *  0x1a       N/A         POL_2       ENAB_2       INT_ID2
 */
#define PCMMIO_PORT_REG(x)                      (0x10 + (x))
#define PCMMIO_INT_PENDING_REG                  0x16
#define PCMMIO_PAGE_LOCK_REG                    0x17
#define PCMMIO_LOCK_PORT(x)                     ((1 << (x)) & 0x3f)
#define PCMMIO_PAGE(x)                          (((x) & 0x3) << 6)
#define PCMMIO_PAGE_MASK                        PCMUIO_PAGE(3)
#define PCMMIO_PAGE_POL                         1
#define PCMMIO_PAGE_ENAB                        2
#define PCMMIO_PAGE_INT_ID                      3
#define PCMMIO_PAGE_REG(x)                      (0x18 + (x))

static const struct comedi_lrange pcmmio_ai_ranges = {
        4, {
                BIP_RANGE(5),
                BIP_RANGE(10),
                UNI_RANGE(5),
                UNI_RANGE(10)
        }
};

static const struct comedi_lrange pcmmio_ao_ranges = {
        6, {
                UNI_RANGE(5),
                UNI_RANGE(10),
                BIP_RANGE(5),
                BIP_RANGE(10),
                BIP_RANGE(2.5),
                RANGE(-2.5, 7.5)
        }
};

struct pcmmio_private {
        spinlock_t pagelock;    /* protects the page registers */
        spinlock_t spinlock;    /* protects the member variables */
        unsigned int enabled_mask;
        unsigned int active:1;
};

static void pcmmio_dio_write(struct comedi_device *dev, unsigned int val,
                             int page, int port)
{
        struct pcmmio_private *devpriv = dev->private;
        unsigned long iobase = dev->iobase;
        unsigned long flags;

        spin_lock_irqsave(&devpriv->pagelock, flags);
        if (page == 0) {
                /* Port registers are valid for any page */
                outb(val & 0xff, iobase + PCMMIO_PORT_REG(port + 0));
                outb((val >> 8) & 0xff, iobase + PCMMIO_PORT_REG(port + 1));
                outb((val >> 16) & 0xff, iobase + PCMMIO_PORT_REG(port + 2));
        } else {
                outb(PCMMIO_PAGE(page), iobase + PCMMIO_PAGE_LOCK_REG);
                outb(val & 0xff, iobase + PCMMIO_PAGE_REG(0));
                outb((val >> 8) & 0xff, iobase + PCMMIO_PAGE_REG(1));
                outb((val >> 16) & 0xff, iobase + PCMMIO_PAGE_REG(2));
        }
        spin_unlock_irqrestore(&devpriv->pagelock, flags);
}

static unsigned int pcmmio_dio_read(struct comedi_device *dev,
                                    int page, int port)
{
        struct pcmmio_private *devpriv = dev->private;
        unsigned long iobase = dev->iobase;
        unsigned long flags;
        unsigned int val;

        spin_lock_irqsave(&devpriv->pagelock, flags);
        if (page == 0) {
                /* Port registers are valid for any page */
                val = inb(iobase + PCMMIO_PORT_REG(port + 0));
                val |= (inb(iobase + PCMMIO_PORT_REG(port + 1)) << 8);
                val |= (inb(iobase + PCMMIO_PORT_REG(port + 2)) << 16);
        } else {
                outb(PCMMIO_PAGE(page), iobase + PCMMIO_PAGE_LOCK_REG);
                val = inb(iobase + PCMMIO_PAGE_REG(0));
                val |= (inb(iobase + PCMMIO_PAGE_REG(1)) << 8);
                val |= (inb(iobase + PCMMIO_PAGE_REG(2)) << 16);
        }
        spin_unlock_irqrestore(&devpriv->pagelock, flags);

        return val;
}

/*
 * Each channel can be individually programmed for input or output.
 * Writing a '0' to a channel causes the corresponding output pin
 * to go to a high-z state (pulled high by an external 10K resistor).
 * This allows it to be used as an input. When used in the input mode,
 * a read reflects the inverted state of the I/O pin, such that a
 * high on the pin will read as a '0' in the register. Writing a '1'
 * to a bit position causes the pin to sink current (up to 12mA),
 * effectively pulling it low.
 */
static int pcmmio_dio_insn_bits(struct comedi_device *dev,
                                struct comedi_subdevice *s,
                                struct comedi_insn *insn,
                                unsigned int *data)
{
        /* subdevice 2 uses ports 0-2, subdevice 3 uses ports 3-5 */
        int port = s->index == 2 ? 0 : 3;
        unsigned int chanmask = (1 << s->n_chan) - 1;
        unsigned int mask;
        unsigned int val;

        mask = comedi_dio_update_state(s, data);
        if (mask) {
                /*
                 * Outputs are inverted, invert the state and
                 * update the channels.
                 *
                 * The s->io_bits mask makes sure the input channels
                 * are '0' so that the outputs pins stay in a high
                 * z-state.
                 */
                val = ~s->state & chanmask;
                val &= s->io_bits;
                pcmmio_dio_write(dev, val, 0, port);
        }

        /* get inverted state of the channels from the port */
        val = pcmmio_dio_read(dev, 0, port);

        /* return the true state of the channels */
        data[1] = ~val & chanmask;

        return insn->n;
}

static int pcmmio_dio_insn_config(struct comedi_device *dev,
                                  struct comedi_subdevice *s,
                                  struct comedi_insn *insn,
                                  unsigned int *data)
{
        /* subdevice 2 uses ports 0-2, subdevice 3 uses ports 3-5 */
        int port = s->index == 2 ? 0 : 3;
        int ret;

        ret = comedi_dio_insn_config(dev, s, insn, data, 0);
        if (ret)
                return ret;

        if (data[0] == INSN_CONFIG_DIO_INPUT)
                pcmmio_dio_write(dev, s->io_bits, 0, port);

        return insn->n;
}

static void pcmmio_reset(struct comedi_device *dev)
{
        /* Clear all the DIO port bits */
        pcmmio_dio_write(dev, 0, 0, 0);
        pcmmio_dio_write(dev, 0, 0, 3);

        /* Clear all the paged registers */
        pcmmio_dio_write(dev, 0, PCMMIO_PAGE_POL, 0);
        pcmmio_dio_write(dev, 0, PCMMIO_PAGE_ENAB, 0);
        pcmmio_dio_write(dev, 0, PCMMIO_PAGE_INT_ID, 0);
}

/* devpriv->spinlock is already locked */
static void pcmmio_stop_intr(struct comedi_device *dev,
                             struct comedi_subdevice *s)
{
        struct pcmmio_private *devpriv = dev->private;

        devpriv->enabled_mask = 0;
        devpriv->active = 0;
        s->async->inttrig = NULL;

        /* disable all dio interrupts */
        pcmmio_dio_write(dev, 0, PCMMIO_PAGE_ENAB, 0);
}

static void pcmmio_handle_dio_intr(struct comedi_device *dev,
                                   struct comedi_subdevice *s,
                                   unsigned int triggered)
{
        struct pcmmio_private *devpriv = dev->private;
        struct comedi_cmd *cmd = &s->async->cmd;
        unsigned int val = 0;
        unsigned long flags;
        int i;

        spin_lock_irqsave(&devpriv->spinlock, flags);

        if (!devpriv->active)
                goto done;

        if (!(triggered & devpriv->enabled_mask))
                goto done;

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

                if (triggered & (1 << chan))
                        val |= (1 << i);
        }

        comedi_buf_write_samples(s, &val, 1);

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

done:
        spin_unlock_irqrestore(&devpriv->spinlock, flags);

        comedi_handle_events(dev, s);
}

static irqreturn_t interrupt_pcmmio(int irq, void *d)
{
        struct comedi_device *dev = d;
        struct comedi_subdevice *s = dev->read_subdev;
        unsigned int triggered;
        unsigned char int_pend;

        /* are there any interrupts pending */
        int_pend = inb(dev->iobase + PCMMIO_INT_PENDING_REG) & 0x07;
        if (!int_pend)
                return IRQ_NONE;

        /* get, and clear, the pending interrupts */
        triggered = pcmmio_dio_read(dev, PCMMIO_PAGE_INT_ID, 0);
        pcmmio_dio_write(dev, 0, PCMMIO_PAGE_INT_ID, 0);

        pcmmio_handle_dio_intr(dev, s, triggered);

        return IRQ_HANDLED;
}

/* devpriv->spinlock is already locked */
static void pcmmio_start_intr(struct comedi_device *dev,
                              struct comedi_subdevice *s)
{
        struct pcmmio_private *devpriv = dev->private;
        struct comedi_cmd *cmd = &s->async->cmd;
        unsigned int bits = 0;
        unsigned int pol_bits = 0;
        int i;

        devpriv->enabled_mask = 0;
        devpriv->active = 1;
        if (cmd->chanlist) {
                for (i = 0; i < cmd->chanlist_len; i++) {
                        unsigned int chanspec = cmd->chanlist[i];
                        unsigned int chan = CR_CHAN(chanspec);
                        unsigned int range = CR_RANGE(chanspec);
                        unsigned int aref = CR_AREF(chanspec);

                        bits |= (1 << chan);
                        pol_bits |= (((aref || range) ? 1 : 0) << chan);
                }
        }
        bits &= ((1 << s->n_chan) - 1);
        devpriv->enabled_mask = bits;

        /* set polarity and enable interrupts */
        pcmmio_dio_write(dev, pol_bits, PCMMIO_PAGE_POL, 0);
        pcmmio_dio_write(dev, bits, PCMMIO_PAGE_ENAB, 0);
}

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

        spin_lock_irqsave(&devpriv->spinlock, flags);
        if (devpriv->active)
                pcmmio_stop_intr(dev, s);
        spin_unlock_irqrestore(&devpriv->spinlock, flags);

        return 0;
}

static int pcmmio_inttrig_start_intr(struct comedi_device *dev,
                                     struct comedi_subdevice *s,
                                     unsigned int trig_num)
{
        struct pcmmio_private *devpriv = dev->private;
        struct comedi_cmd *cmd = &s->async->cmd;
        unsigned long flags;

        if (trig_num != cmd->start_arg)
                return -EINVAL;

        spin_lock_irqsave(&devpriv->spinlock, flags);
        s->async->inttrig = NULL;
        if (devpriv->active)
                pcmmio_start_intr(dev, s);
        spin_unlock_irqrestore(&devpriv->spinlock, flags);

        return 1;
}

/*
 * 'do_cmd' function for an 'INTERRUPT' subdevice.
 */
static int pcmmio_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
{
        struct pcmmio_private *devpriv = dev->private;
        struct comedi_cmd *cmd = &s->async->cmd;
        unsigned long flags;

        spin_lock_irqsave(&devpriv->spinlock, flags);
        devpriv->active = 1;

        /* Set up start of acquisition. */
        if (cmd->start_src == TRIG_INT)
                s->async->inttrig = pcmmio_inttrig_start_intr;
        else    /* TRIG_NOW */
                pcmmio_start_intr(dev, s);

        spin_unlock_irqrestore(&devpriv->spinlock, flags);

        return 0;
}

static int pcmmio_cmdtest(struct comedi_device *dev,
                          struct comedi_subdevice *s,
                          struct comedi_cmd *cmd)
{
        int err = 0;

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

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

        if (err)
                return 1;

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

        err |= comedi_check_trigger_is_unique(cmd->start_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);
        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 (err) return 4; */

        return 0;
}

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

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

static int pcmmio_ai_insn_read(struct comedi_device *dev,
                               struct comedi_subdevice *s,
                               struct comedi_insn *insn,
                               unsigned int *data)
{
        unsigned long iobase = dev->iobase;
        unsigned int chan = CR_CHAN(insn->chanspec);
        unsigned int range = CR_RANGE(insn->chanspec);
        unsigned int aref = CR_AREF(insn->chanspec);
        unsigned char cmd = 0;
        unsigned int val;
        int ret;
        int i;

        /*
         * The PCM-MIO uses two Linear Tech LTC1859CG 8-channel A/D converters.
         * The devices use a full duplex serial interface which transmits and
         * receives data simultaneously. An 8-bit command is shifted into the
         * ADC interface to configure it for the next conversion. At the same
         * time, the data from the previous conversion is shifted out of the
         * device. Consequently, the conversion result is delayed by one
         * conversion from the command word.
         *
         * Setup the cmd for the conversions then do a dummy conversion to
         * flush the junk data. Then do each conversion requested by the
         * comedi_insn. Note that the last conversion will leave junk data
         * in ADC which will get flushed on the next comedi_insn.
         */

        if (chan > 7) {
                chan -= 8;
                iobase += PCMMIO_AI_2ND_ADC_OFFSET;
        }

        if (aref == AREF_GROUND)
                cmd |= PCMMIO_AI_CMD_SE;
        if (chan % 2)
                cmd |= PCMMIO_AI_CMD_ODD_CHAN;
        cmd |= PCMMIO_AI_CMD_CHAN_SEL(chan / 2);
        cmd |= PCMMIO_AI_CMD_RANGE(range);

        outb(cmd, iobase + PCMMIO_AI_CMD_REG);

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

        val = inb(iobase + PCMMIO_AI_LSB_REG);
        val |= inb(iobase + PCMMIO_AI_MSB_REG) << 8;

        for (i = 0; i < insn->n; i++) {
                outb(cmd, iobase + PCMMIO_AI_CMD_REG);

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

                val = inb(iobase + PCMMIO_AI_LSB_REG);
                val |= inb(iobase + PCMMIO_AI_MSB_REG) << 8;

                /* bipolar data is two's complement */
                if (comedi_range_is_bipolar(s, range))
                        val = comedi_offset_munge(s, val);

                data[i] = val;
        }

        return insn->n;
}

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

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

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

        /*
         * The PCM-MIO has two Linear Tech LTC2704 DAC devices. Each device
         * is a 4-channel converter with software-selectable output range.
         */

        if (chan > 3) {
                cmd |= PCMMIO_AO_CMD_CHAN_SEL(chan - 4);
                iobase += PCMMIO_AO_2ND_DAC_OFFSET;
        } else {
                cmd |= PCMMIO_AO_CMD_CHAN_SEL(chan);
        }

        /* set the range for the channel */
        outb(PCMMIO_AO_LSB_SPAN(range), iobase + PCMMIO_AO_LSB_REG);
        outb(0, iobase + PCMMIO_AO_MSB_REG);
        outb(cmd | PCMMIO_AO_CMD_WR_SPAN_UPDATE, iobase + PCMMIO_AO_CMD_REG);

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

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

                /* write the data to the channel */
                outb(val & 0xff, iobase + PCMMIO_AO_LSB_REG);
                outb((val >> 8) & 0xff, iobase + PCMMIO_AO_MSB_REG);
                outb(cmd | PCMMIO_AO_CMD_WR_CODE_UPDATE,
                     iobase + PCMMIO_AO_CMD_REG);

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

                s->readback[chan] = val;
        }

        return insn->n;
}

static int pcmmio_attach(struct comedi_device *dev, struct comedi_devconfig *it)
{
        struct pcmmio_private *devpriv;
        struct comedi_subdevice *s;
        int ret;

        ret = comedi_request_region(dev, it->options[0], 32);
        if (ret)
                return ret;

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

        spin_lock_init(&devpriv->pagelock);
        spin_lock_init(&devpriv->spinlock);

        pcmmio_reset(dev);

        if (it->options[1]) {
                ret = request_irq(it->options[1], interrupt_pcmmio, 0,
                                  dev->board_name, dev);
                if (ret == 0) {
                        dev->irq = it->options[1];

                        /* configure the interrupt routing on the board */
                        outb(PCMMIO_AI_RES_ENA_DIO_RES_ACCESS,
                             dev->iobase + PCMMIO_AI_RES_ENA_REG);
                        outb(PCMMIO_RESOURCE_IRQ(dev->irq),
                             dev->iobase + PCMMIO_RESOURCE_REG);
                }
        }

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

        /* Analog Input subdevice */
        s = &dev->subdevices[0];
        s->type         = COMEDI_SUBD_AI;
        s->subdev_flags = SDF_READABLE | SDF_GROUND | SDF_DIFF;
        s->n_chan       = 16;
        s->maxdata      = 0xffff;
        s->range_table  = &pcmmio_ai_ranges;
        s->insn_read    = pcmmio_ai_insn_read;

        /* initialize the resource enable register by clearing it */
        outb(PCMMIO_AI_RES_ENA_CMD_REG_ACCESS,
             dev->iobase + PCMMIO_AI_RES_ENA_REG);
        outb(PCMMIO_AI_RES_ENA_CMD_REG_ACCESS,
             dev->iobase + PCMMIO_AI_RES_ENA_REG + PCMMIO_AI_2ND_ADC_OFFSET);

        /* Analog Output subdevice */
        s = &dev->subdevices[1];
        s->type         = COMEDI_SUBD_AO;
        s->subdev_flags = SDF_READABLE;
        s->n_chan       = 8;
        s->maxdata      = 0xffff;
        s->range_table  = &pcmmio_ao_ranges;
        s->insn_write   = pcmmio_ao_insn_write;

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

        /* initialize the resource enable register by clearing it */
        outb(0, dev->iobase + PCMMIO_AO_RESOURCE_ENA_REG);
        outb(0, dev->iobase + PCMMIO_AO_2ND_DAC_OFFSET +
                PCMMIO_AO_RESOURCE_ENA_REG);

        /* Digital I/O subdevice with interrupt support */
        s = &dev->subdevices[2];
        s->type         = COMEDI_SUBD_DIO;
        s->subdev_flags = SDF_READABLE | SDF_WRITABLE;
        s->n_chan       = 24;
        s->maxdata      = 1;
        s->len_chanlist = 1;
        s->range_table  = &range_digital;
        s->insn_bits    = pcmmio_dio_insn_bits;
        s->insn_config  = pcmmio_dio_insn_config;
        if (dev->irq) {
                dev->read_subdev = s;
                s->subdev_flags |= SDF_CMD_READ | SDF_LSAMPL | SDF_PACKED;
                s->len_chanlist = s->n_chan;
                s->cancel       = pcmmio_cancel;
                s->do_cmd       = pcmmio_cmd;
                s->do_cmdtest   = pcmmio_cmdtest;
        }

        /* Digital I/O subdevice */
        s = &dev->subdevices[3];
        s->type         = COMEDI_SUBD_DIO;
        s->subdev_flags = SDF_READABLE | SDF_WRITABLE;
        s->n_chan       = 24;
        s->maxdata      = 1;
        s->range_table  = &range_digital;
        s->insn_bits    = pcmmio_dio_insn_bits;
        s->insn_config  = pcmmio_dio_insn_config;

        return 0;
}

static struct comedi_driver pcmmio_driver = {
        .driver_name    = "pcmmio",
        .module         = THIS_MODULE,
        .attach         = pcmmio_attach,
        .detach         = comedi_legacy_detach,
};
module_comedi_driver(pcmmio_driver);

MODULE_AUTHOR("Comedi https://www.comedi.org");
MODULE_DESCRIPTION("Comedi driver for Winsystems PCM-MIO PC/104 board");
MODULE_LICENSE("GPL");