/*
    comedi/drivers/dmm32at.c
    Diamond Systems mm32at code for a Comedi driver

    COMEDI - Linux Control and Measurement Device Interface
    Copyright (C) 2000 David A. Schleef <ds@schleef.org>

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

*/
/*
Driver: dmm32at
Description: Diamond Systems mm32at driver.
Devices:
Author: Perry J. Piplani <perry.j.piplani@nasa.gov>
Updated: Fri Jun  4 09:13:24 CDT 2004
Status: experimental

This driver is for the Diamond Systems MM-32-AT board
http://www.diamondsystems.com/products/diamondmm32at It is being used
on serveral projects inside NASA, without problems so far. For analog
input commands, TRIG_EXT is not yet supported at all..

Configuration Options:
  comedi_config /dev/comedi0 dmm32at baseaddr,irq
*/

/*
 * The previous block comment is used to automatically generate
 * documentation in Comedi and Comedilib.  The fields:
 *
 * Driver: the name of the driver
 * Description: a short phrase describing the driver.  Don't list boards.
 * Devices: a full list of the boards that attempt to be supported by
 *   the driver.  Format is "(manufacturer) board name [comedi name]",
 *   where comedi_name is the name that is used to configure the board.
 *   See the comment near board_name: in the struct comedi_driver structure
 *   below.  If (manufacturer) or [comedi name] is missing, the previous
 *   value is used.
 * Author: you
 * Updated: date when the _documentation_ was last updated.  Use 'date -R'
 *   to get a value for this.
 * Status: a one-word description of the status.  Valid values are:
 *   works - driver works correctly on most boards supported, and
 *     passes comedi_test.
 *   unknown - unknown.  Usually put there by ds.
 *   experimental - may not work in any particular release.  Author
 *     probably wants assistance testing it.
 *   bitrotten - driver has not been update in a long time, probably
 *     doesn't work, and probably is missing support for significant
 *     Comedi interface features.
 *   untested - author probably wrote it "blind", and is believed to
 *     work, but no confirmation.
 *
 * These headers should be followed by a blank line, and any comments
 * you wish to say about the driver.  The comment area is the place
 * to put any known bugs, limitations, unsupported features, supported
 * command triggers, whether or not commands are supported on particular
 * subdevices, etc.
 *
 * Somewhere in the comment should be information about configuration
 * options that are used with comedi_config.
 */

#include <linux/interrupt.h>
#include "../comedidev.h"
#include <linux/ioport.h>

/* Board register addresses */

#define DMM32AT_MEMSIZE 0x10

#define DMM32AT_CONV 0x00
#define DMM32AT_AILSB 0x00
#define DMM32AT_AUXDOUT 0x01
#define DMM32AT_AIMSB 0x01
#define DMM32AT_AILOW 0x02
#define DMM32AT_AIHIGH 0x03

#define DMM32AT_DACLSB 0x04
#define DMM32AT_DACSTAT 0x04
#define DMM32AT_DACMSB 0x05

#define DMM32AT_FIFOCNTRL 0x07
#define DMM32AT_FIFOSTAT 0x07

#define DMM32AT_CNTRL 0x08
#define DMM32AT_AISTAT 0x08

#define DMM32AT_INTCLOCK 0x09

#define DMM32AT_CNTRDIO 0x0a

#define DMM32AT_AICONF 0x0b
#define DMM32AT_AIRBACK 0x0b

#define DMM32AT_CLK1 0x0d
#define DMM32AT_CLK2 0x0e
#define DMM32AT_CLKCT 0x0f

#define DMM32AT_DIOA 0x0c
#define DMM32AT_DIOB 0x0d
#define DMM32AT_DIOC 0x0e
#define DMM32AT_DIOCONF 0x0f

#define dmm_inb(cdev, reg) inb((cdev->iobase)+reg)
#define dmm_outb(cdev, reg, valu) outb(valu, (cdev->iobase)+reg)

/* Board register values. */

/* DMM32AT_DACSTAT 0x04 */
#define DMM32AT_DACBUSY 0x80

/* DMM32AT_FIFOCNTRL 0x07 */
#define DMM32AT_FIFORESET 0x02
#define DMM32AT_SCANENABLE 0x04

/* DMM32AT_CNTRL 0x08 */
#define DMM32AT_RESET 0x20
#define DMM32AT_INTRESET 0x08
#define DMM32AT_CLKACC 0x00
#define DMM32AT_DIOACC 0x01

/* DMM32AT_AISTAT 0x08 */
#define DMM32AT_STATUS 0x80

/* DMM32AT_INTCLOCK 0x09 */
#define DMM32AT_ADINT 0x80
#define DMM32AT_CLKSEL 0x03

/* DMM32AT_CNTRDIO 0x0a */
#define DMM32AT_FREQ12 0x80

/* DMM32AT_AICONF 0x0b */
#define DMM32AT_RANGE_U10 0x0c
#define DMM32AT_RANGE_U5 0x0d
#define DMM32AT_RANGE_B10 0x08
#define DMM32AT_RANGE_B5 0x00
#define DMM32AT_SCINT_20 0x00
#define DMM32AT_SCINT_15 0x10
#define DMM32AT_SCINT_10 0x20
#define DMM32AT_SCINT_5 0x30

/* DMM32AT_CLKCT 0x0f */
#define DMM32AT_CLKCT1 0x56     /* mode3 counter 1 - write low byte only */
#define DMM32AT_CLKCT2 0xb6     /*  mode3 counter 2 - write high and low byte */

/* DMM32AT_DIOCONF 0x0f */
#define DMM32AT_DIENABLE 0x80
#define DMM32AT_DIRA 0x10
#define DMM32AT_DIRB 0x02
#define DMM32AT_DIRCL 0x01
#define DMM32AT_DIRCH 0x08

/* board AI ranges in comedi structure */
static const struct comedi_lrange dmm32at_airanges = {
        4,
        {
         UNI_RANGE(10),
         UNI_RANGE(5),
         BIP_RANGE(10),
         BIP_RANGE(5),
         }
};

/* register values for above ranges */
static const unsigned char dmm32at_rangebits[] = {
        DMM32AT_RANGE_U10,
        DMM32AT_RANGE_U5,
        DMM32AT_RANGE_B10,
        DMM32AT_RANGE_B5,
};

/* only one of these ranges is valid, as set by a jumper on the
 * board. The application should only use the range set by the jumper
 */
static const struct comedi_lrange dmm32at_aoranges = {
        4,
        {
         UNI_RANGE(10),
         UNI_RANGE(5),
         BIP_RANGE(10),
         BIP_RANGE(5),
         }
};

/*
 * Board descriptions for two imaginary boards.  Describing the
 * boards in this way is optional, and completely driver-dependent.
 * Some drivers use arrays such as this, other do not.
 */
struct dmm32at_board {
        const char *name;
        int ai_chans;
        int ai_bits;
        const struct comedi_lrange *ai_ranges;
        int ao_chans;
        int ao_bits;
        const struct comedi_lrange *ao_ranges;
        int have_dio;
        int dio_chans;
};
static const struct dmm32at_board dmm32at_boards[] = {
        {
         .name = "dmm32at",
         .ai_chans = 32,
         .ai_bits = 16,
         .ai_ranges = &dmm32at_airanges,
         .ao_chans = 4,
         .ao_bits = 12,
         .ao_ranges = &dmm32at_aoranges,
         .have_dio = 1,
         .dio_chans = 24,
         },
};

/*
 * Useful for shorthand access to the particular board structure
 */
#define thisboard ((const struct dmm32at_board *)dev->board_ptr)

/* this structure is for data unique to this hardware driver.  If
 * several hardware drivers keep similar information in this structure,
 * feel free to suggest moving the variable to the struct comedi_device struct.
 */
struct dmm32at_private {

        int data;
        int ai_inuse;
        unsigned int ai_scans_left;

        /* Used for AO readback */
        unsigned int ao_readback[4];
        unsigned char dio_config;

};

/*
 * most drivers define the following macro to make it easy to
 * access the private structure.
 */
#define devpriv ((struct dmm32at_private *)dev->private)

/*
 * The struct comedi_driver structure tells the Comedi core module
 * which functions to call to configure/deconfigure (attach/detach)
 * the board, and also about the kernel module that contains
 * the device code.
 */
static int dmm32at_attach(struct comedi_device *dev,
                          struct comedi_devconfig *it);
static int dmm32at_detach(struct comedi_device *dev);
static struct comedi_driver driver_dmm32at = {
        .driver_name = "dmm32at",
        .module = THIS_MODULE,
        .attach = dmm32at_attach,
        .detach = dmm32at_detach,
/* It is not necessary to implement the following members if you are
 * writing a driver for a ISA PnP or PCI card */
/* Most drivers will support multiple types of boards by
 * having an array of board structures.  These were defined
 * in dmm32at_boards[] above.  Note that the element 'name'
 * was first in the structure -- Comedi uses this fact to
 * extract the name of the board without knowing any details
 * about the structure except for its length.
 * When a device is attached (by comedi_config), the name
 * of the device is given to Comedi, and Comedi tries to
 * match it by going through the list of board names.  If
 * there is a match, the address of the pointer is put
 * into dev->board_ptr and driver->attach() is called.
 *
 * Note that these are not necessary if you can determine
 * the type of board in software.  ISA PnP, PCI, and PCMCIA
 * devices are such boards.
 */
        .board_name = &dmm32at_boards[0].name,
        .offset = sizeof(struct dmm32at_board),
        .num_names = ARRAY_SIZE(dmm32at_boards),
};

/* prototypes for driver functions below */
static int dmm32at_ai_rinsn(struct comedi_device *dev,
                            struct comedi_subdevice *s,
                            struct comedi_insn *insn, unsigned int *data);
static int dmm32at_ao_winsn(struct comedi_device *dev,
                            struct comedi_subdevice *s,
                            struct comedi_insn *insn, unsigned int *data);
static int dmm32at_ao_rinsn(struct comedi_device *dev,
                            struct comedi_subdevice *s,
                            struct comedi_insn *insn, unsigned int *data);
static int dmm32at_dio_insn_bits(struct comedi_device *dev,
                                 struct comedi_subdevice *s,
                                 struct comedi_insn *insn, unsigned int *data);
static int dmm32at_dio_insn_config(struct comedi_device *dev,
                                   struct comedi_subdevice *s,
                                   struct comedi_insn *insn,
                                   unsigned int *data);
static int dmm32at_ai_cmdtest(struct comedi_device *dev,
                              struct comedi_subdevice *s,
                              struct comedi_cmd *cmd);
static int dmm32at_ai_cmd(struct comedi_device *dev,
                          struct comedi_subdevice *s);
static int dmm32at_ai_cancel(struct comedi_device *dev,
                             struct comedi_subdevice *s);
static int dmm32at_ns_to_timer(unsigned int *ns, int round);
static irqreturn_t dmm32at_isr(int irq, void *d);
void dmm32at_setaitimer(struct comedi_device *dev, unsigned int nansec);

/*
 * Attach is called by the Comedi core to configure the driver
 * for a particular board.  If you specified a board_name array
 * in the driver structure, dev->board_ptr contains that
 * address.
 */
static int dmm32at_attach(struct comedi_device *dev,
                          struct comedi_devconfig *it)
{
        int ret;
        struct comedi_subdevice *s;
        unsigned char aihi, ailo, fifostat, aistat, intstat, airback;
        unsigned long iobase;
        unsigned int irq;

        iobase = it->options[0];
        irq = it->options[1];

        printk("comedi%d: dmm32at: attaching\n", dev->minor);
        printk("dmm32at: probing at address 0x%04lx, irq %u\n", iobase, irq);

        /* register address space */
        if (!request_region(iobase, DMM32AT_MEMSIZE, thisboard->name)) {
                printk("I/O port conflict\n");
                return -EIO;
        }
        dev->iobase = iobase;

        /* the following just makes sure the board is there and gets
           it to a known state */

        /* reset the board */
        dmm_outb(dev, DMM32AT_CNTRL, DMM32AT_RESET);

        /* allow a millisecond to reset */
        udelay(1000);

        /* zero scan and fifo control */
        dmm_outb(dev, DMM32AT_FIFOCNTRL, 0x0);

        /* zero interrupt and clock control */
        dmm_outb(dev, DMM32AT_INTCLOCK, 0x0);

        /* write a test channel range, the high 3 bits should drop */
        dmm_outb(dev, DMM32AT_AILOW, 0x80);
        dmm_outb(dev, DMM32AT_AIHIGH, 0xff);

        /* set the range at 10v unipolar */
        dmm_outb(dev, DMM32AT_AICONF, DMM32AT_RANGE_U10);

        /* should take 10 us to settle, here's a hundred */
        udelay(100);

        /* read back the values */
        ailo = dmm_inb(dev, DMM32AT_AILOW);
        aihi = dmm_inb(dev, DMM32AT_AIHIGH);
        fifostat = dmm_inb(dev, DMM32AT_FIFOSTAT);
        aistat = dmm_inb(dev, DMM32AT_AISTAT);
        intstat = dmm_inb(dev, DMM32AT_INTCLOCK);
        airback = dmm_inb(dev, DMM32AT_AIRBACK);

        printk("dmm32at: lo=0x%02x hi=0x%02x fifostat=0x%02x\n",
               ailo, aihi, fifostat);
        printk("dmm32at: aistat=0x%02x intstat=0x%02x airback=0x%02x\n",
               aistat, intstat, airback);

        if ((ailo != 0x00) || (aihi != 0x1f) || (fifostat != 0x80) ||
            (aistat != 0x60 || (intstat != 0x00) || airback != 0x0c)) {
                printk("dmmat32: board detection failed\n");
                return -EIO;
        }

        /* board is there, register interrupt */
        if (irq) {
                ret = request_irq(irq, dmm32at_isr, 0, thisboard->name, dev);
                if (ret < 0) {
                        printk("irq conflict\n");
                        return ret;
                }
                dev->irq = irq;
        }

/*
 * If you can probe the device to determine what device in a series
 * it is, this is the place to do it.  Otherwise, dev->board_ptr
 * should already be initialized.
 */
        /* dev->board_ptr = dmm32at_probe(dev); */

/*
 * Initialize dev->board_name.  Note that we can use the "thisboard"
 * macro now, since we just initialized it in the last line.
 */
        dev->board_name = thisboard->name;

/*
 * Allocate the private structure area.  alloc_private() is a
 * convenient macro defined in comedidev.h.
 */
        if (alloc_private(dev, sizeof(struct dmm32at_private)) < 0)
                return -ENOMEM;

/*
 * Allocate the subdevice structures.  alloc_subdevice() is a
 * convenient macro defined in comedidev.h.
 */
        if (alloc_subdevices(dev, 3) < 0)
                return -ENOMEM;

        s = dev->subdevices + 0;
        dev->read_subdev = s;
        /* analog input subdevice */
        s->type = COMEDI_SUBD_AI;
        /* we support single-ended (ground) and differential */
        s->subdev_flags = SDF_READABLE | SDF_GROUND | SDF_DIFF | SDF_CMD_READ;
        s->n_chan = thisboard->ai_chans;
        s->maxdata = (1 << thisboard->ai_bits) - 1;
        s->range_table = thisboard->ai_ranges;
        s->len_chanlist = 32;   /* This is the maximum chanlist length that
                                   the board can handle */
        s->insn_read = dmm32at_ai_rinsn;
        s->do_cmd = dmm32at_ai_cmd;
        s->do_cmdtest = dmm32at_ai_cmdtest;
        s->cancel = dmm32at_ai_cancel;

        s = dev->subdevices + 1;
        /* analog output subdevice */
        s->type = COMEDI_SUBD_AO;
        s->subdev_flags = SDF_WRITABLE;
        s->n_chan = thisboard->ao_chans;
        s->maxdata = (1 << thisboard->ao_bits) - 1;
        s->range_table = thisboard->ao_ranges;
        s->insn_write = dmm32at_ao_winsn;
        s->insn_read = dmm32at_ao_rinsn;

        s = dev->subdevices + 2;
        /* digital i/o subdevice */
        if (thisboard->have_dio) {

                /* get access to the DIO regs */
                dmm_outb(dev, DMM32AT_CNTRL, DMM32AT_DIOACC);
                /* set the DIO's to the defualt input setting */
                devpriv->dio_config = DMM32AT_DIRA | DMM32AT_DIRB |
                    DMM32AT_DIRCL | DMM32AT_DIRCH | DMM32AT_DIENABLE;
                dmm_outb(dev, DMM32AT_DIOCONF, devpriv->dio_config);

                /* set up the subdevice */
                s->type = COMEDI_SUBD_DIO;
                s->subdev_flags = SDF_READABLE | SDF_WRITABLE;
                s->n_chan = thisboard->dio_chans;
                s->maxdata = 1;
                s->state = 0;
                s->range_table = &range_digital;
                s->insn_bits = dmm32at_dio_insn_bits;
                s->insn_config = dmm32at_dio_insn_config;
        } else {
                s->type = COMEDI_SUBD_UNUSED;
        }

        /* success */
        printk("comedi%d: dmm32at: attached\n", dev->minor);

        return 1;

}

/*
 * _detach is called to deconfigure a device.  It should deallocate
 * resources.
 * This function is also called when _attach() fails, so it should be
 * careful not to release resources that were not necessarily
 * allocated by _attach().  dev->private and dev->subdevices are
 * deallocated automatically by the core.
 */
static int dmm32at_detach(struct comedi_device *dev)
{
        printk("comedi%d: dmm32at: remove\n", dev->minor);
        if (dev->irq)
                free_irq(dev->irq, dev);
        if (dev->iobase)
                release_region(dev->iobase, DMM32AT_MEMSIZE);

        return 0;
}

/*
 * "instructions" read/write data in "one-shot" or "software-triggered"
 * mode.
 */

static int dmm32at_ai_rinsn(struct comedi_device *dev,
                            struct comedi_subdevice *s,
                            struct comedi_insn *insn, unsigned int *data)
{
        int n, i;
        unsigned int d;
        unsigned char status;
        unsigned short msb, lsb;
        unsigned char chan;
        int range;

        /* get the channel and range number */

        chan = CR_CHAN(insn->chanspec) & (s->n_chan - 1);
        range = CR_RANGE(insn->chanspec);

        /* printk("channel=0x%02x, range=%d\n",chan,range); */

        /* zero scan and fifo control and reset fifo */
        dmm_outb(dev, DMM32AT_FIFOCNTRL, DMM32AT_FIFORESET);

        /* write the ai channel range regs */
        dmm_outb(dev, DMM32AT_AILOW, chan);
        dmm_outb(dev, DMM32AT_AIHIGH, chan);
        /* set the range bits */
        dmm_outb(dev, DMM32AT_AICONF, dmm32at_rangebits[range]);

        /* wait for circuit to settle */
        for (i = 0; i < 40000; i++) {
                status = dmm_inb(dev, DMM32AT_AIRBACK);
                if ((status & DMM32AT_STATUS) == 0)
                        break;
        }
        if (i == 40000) {
                printk("timeout\n");
                return -ETIMEDOUT;
        }

        /* convert n samples */
        for (n = 0; n < insn->n; n++) {
                /* trigger conversion */
                dmm_outb(dev, DMM32AT_CONV, 0xff);
                /* wait for conversion to end */
                for (i = 0; i < 40000; i++) {
                        status = dmm_inb(dev, DMM32AT_AISTAT);
                        if ((status & DMM32AT_STATUS) == 0)
                                break;
                }
                if (i == 40000) {
                        printk("timeout\n");
                        return -ETIMEDOUT;
                }

                /* read data */
                lsb = dmm_inb(dev, DMM32AT_AILSB);
                msb = dmm_inb(dev, DMM32AT_AIMSB);

                /* invert sign bit to make range unsigned, this is an
                   idiosyncracy of the diamond board, it return
                   conversions as a signed value, i.e. -32768 to
                   32767, flipping the bit and interpreting it as
                   signed gives you a range of 0 to 65535 which is
                   used by comedi */
                d = ((msb ^ 0x0080) << 8) + lsb;

                data[n] = d;
        }

        /* return the number of samples read/written */
        return n;
}

static int dmm32at_ai_cmdtest(struct comedi_device *dev,
                              struct comedi_subdevice *s,
                              struct comedi_cmd *cmd)
{
        int err = 0;
        int tmp;
        int start_chan, gain, i;

        /* printk("dmmat32 in command test\n"); */

        /* cmdtest tests a particular command to see if it is valid.
         * Using the cmdtest ioctl, a user can create a valid cmd
         * and then have it executes by the cmd ioctl.
         *
         * cmdtest returns 1,2,3,4 or 0, depending on which tests
         * the command passes. */

        /* step 1: make sure trigger sources are trivially valid */

        tmp = cmd->start_src;
        cmd->start_src &= TRIG_NOW;
        if (!cmd->start_src || tmp != cmd->start_src)
                err++;

        tmp = cmd->scan_begin_src;
        cmd->scan_begin_src &= TRIG_TIMER /*| TRIG_EXT */ ;
        if (!cmd->scan_begin_src || tmp != cmd->scan_begin_src)
                err++;

        tmp = cmd->convert_src;
        cmd->convert_src &= TRIG_TIMER /*| TRIG_EXT */ ;
        if (!cmd->convert_src || tmp != cmd->convert_src)
                err++;

        tmp = cmd->scan_end_src;
        cmd->scan_end_src &= TRIG_COUNT;
        if (!cmd->scan_end_src || tmp != cmd->scan_end_src)
                err++;

        tmp = cmd->stop_src;
        cmd->stop_src &= TRIG_COUNT | TRIG_NONE;
        if (!cmd->stop_src || tmp != cmd->stop_src)
                err++;

        if (err)
                return 1;

        /* step 2: make sure trigger sources are unique and mutually compatible */

        /* note that mutual compatiblity is not an issue here */
        if (cmd->scan_begin_src != TRIG_TIMER &&
            cmd->scan_begin_src != TRIG_EXT)
                err++;
        if (cmd->convert_src != TRIG_TIMER && cmd->convert_src != TRIG_EXT)
                err++;
        if (cmd->stop_src != TRIG_COUNT && cmd->stop_src != TRIG_NONE)
                err++;

        if (err)
                return 2;

        /* step 3: make sure arguments are trivially compatible */

        if (cmd->start_arg != 0) {
                cmd->start_arg = 0;
                err++;
        }
#define MAX_SCAN_SPEED  1000000 /* in nanoseconds */
#define MIN_SCAN_SPEED  1000000000      /* in nanoseconds */

        if (cmd->scan_begin_src == TRIG_TIMER) {
                if (cmd->scan_begin_arg < MAX_SCAN_SPEED) {
                        cmd->scan_begin_arg = MAX_SCAN_SPEED;
                        err++;
                }
                if (cmd->scan_begin_arg > MIN_SCAN_SPEED) {
                        cmd->scan_begin_arg = MIN_SCAN_SPEED;
                        err++;
                }
        } else {
                /* external trigger */
                /* should be level/edge, hi/lo specification here */
                /* should specify multiple external triggers */
                if (cmd->scan_begin_arg > 9) {
                        cmd->scan_begin_arg = 9;
                        err++;
                }
        }
        if (cmd->convert_src == TRIG_TIMER) {
                if (cmd->convert_arg >= 17500)
                        cmd->convert_arg = 20000;
                else if (cmd->convert_arg >= 12500)
                        cmd->convert_arg = 15000;
                else if (cmd->convert_arg >= 7500)
                        cmd->convert_arg = 10000;
                else
                        cmd->convert_arg = 5000;

        } else {
                /* external trigger */
                /* see above */
                if (cmd->convert_arg > 9) {
                        cmd->convert_arg = 9;
                        err++;
                }
        }

        if (cmd->scan_end_arg != cmd->chanlist_len) {
                cmd->scan_end_arg = cmd->chanlist_len;
                err++;
        }
        if (cmd->stop_src == TRIG_COUNT) {
                if (cmd->stop_arg > 0xfffffff0) {
                        cmd->stop_arg = 0xfffffff0;
                        err++;
                }
                if (cmd->stop_arg == 0) {
                        cmd->stop_arg = 1;
                        err++;
                }
        } else {
                /* TRIG_NONE */
                if (cmd->stop_arg != 0) {
                        cmd->stop_arg = 0;
                        err++;
                }
        }

        if (err)
                return 3;

        /* step 4: fix up any arguments */

        if (cmd->scan_begin_src == TRIG_TIMER) {
                tmp = cmd->scan_begin_arg;
                dmm32at_ns_to_timer(&cmd->scan_begin_arg,
                                    cmd->flags & TRIG_ROUND_MASK);
                if (tmp != cmd->scan_begin_arg)
                        err++;
        }
        if (cmd->convert_src == TRIG_TIMER) {
                tmp = cmd->convert_arg;
                dmm32at_ns_to_timer(&cmd->convert_arg,
                                    cmd->flags & TRIG_ROUND_MASK);
                if (tmp != cmd->convert_arg)
                        err++;
                if (cmd->scan_begin_src == TRIG_TIMER &&
                    cmd->scan_begin_arg <
                    cmd->convert_arg * cmd->scan_end_arg) {
                        cmd->scan_begin_arg =
                            cmd->convert_arg * cmd->scan_end_arg;
                        err++;
                }
        }

        if (err)
                return 4;

        /* step 5 check the channel list, the channel list for this
           board must be consecutive and gains must be the same */

        if (cmd->chanlist) {
                gain = CR_RANGE(cmd->chanlist[0]);
                start_chan = CR_CHAN(cmd->chanlist[0]);
                for (i = 1; i < cmd->chanlist_len; i++) {
                        if (CR_CHAN(cmd->chanlist[i]) !=
                            (start_chan + i) % s->n_chan) {
                                comedi_error(dev,
                                             "entries in chanlist must be consecutive channels, counting upwards\n");
                                err++;
                        }
                        if (CR_RANGE(cmd->chanlist[i]) != gain) {
                                comedi_error(dev,
                                             "entries in chanlist must all have the same gain\n");
                                err++;
                        }
                }
        }

        if (err)
                return 5;

        return 0;
}

static int dmm32at_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
{
        struct comedi_cmd *cmd = &s->async->cmd;
        int i, range;
        unsigned char chanlo, chanhi, status;

        if (!cmd->chanlist)
                return -EINVAL;

        /* get the channel list and range */
        chanlo = CR_CHAN(cmd->chanlist[0]) & (s->n_chan - 1);
        chanhi = chanlo + cmd->chanlist_len - 1;
        if (chanhi >= s->n_chan)
                return -EINVAL;
        range = CR_RANGE(cmd->chanlist[0]);

        /* reset fifo */
        dmm_outb(dev, DMM32AT_FIFOCNTRL, DMM32AT_FIFORESET);

        /* set scan enable */
        dmm_outb(dev, DMM32AT_FIFOCNTRL, DMM32AT_SCANENABLE);

        /* write the ai channel range regs */
        dmm_outb(dev, DMM32AT_AILOW, chanlo);
        dmm_outb(dev, DMM32AT_AIHIGH, chanhi);

        /* set the range bits */
        dmm_outb(dev, DMM32AT_AICONF, dmm32at_rangebits[range]);

        /* reset the interrupt just in case */
        dmm_outb(dev, DMM32AT_CNTRL, DMM32AT_INTRESET);

        if (cmd->stop_src == TRIG_COUNT)
                devpriv->ai_scans_left = cmd->stop_arg;
        else {                  /* TRIG_NONE */
                devpriv->ai_scans_left = 0xffffffff;    /* indicates TRIG_NONE to isr */
        }

        /* wait for circuit to settle */
        for (i = 0; i < 40000; i++) {
                status = dmm_inb(dev, DMM32AT_AIRBACK);
                if ((status & DMM32AT_STATUS) == 0)
                        break;
        }
        if (i == 40000) {
                printk("timeout\n");
                return -ETIMEDOUT;
        }

        if (devpriv->ai_scans_left > 1) {
                /* start the clock and enable the interrupts */
                dmm32at_setaitimer(dev, cmd->scan_begin_arg);
        } else {
                /* start the interrups and initiate a single scan */
                dmm_outb(dev, DMM32AT_INTCLOCK, DMM32AT_ADINT);
                dmm_outb(dev, DMM32AT_CONV, 0xff);
        }

/*      printk("dmmat32 in command\n"); */

/*      for(i=0;i<cmd->chanlist_len;i++) */
/*              comedi_buf_put(s->async,i*100); */

/*      s->async->events |= COMEDI_CB_EOA; */
/*      comedi_event(dev, s); */

        return 0;

}

static int dmm32at_ai_cancel(struct comedi_device *dev,
                             struct comedi_subdevice *s)
{
        devpriv->ai_scans_left = 1;
        return 0;
}

static irqreturn_t dmm32at_isr(int irq, void *d)
{
        unsigned char intstat;
        unsigned int samp;
        unsigned short msb, lsb;
        int i;
        struct comedi_device *dev = d;

        if (!dev->attached) {
                comedi_error(dev, "spurious interrupt");
                return IRQ_HANDLED;
        }

        intstat = dmm_inb(dev, DMM32AT_INTCLOCK);

        if (intstat & DMM32AT_ADINT) {
                struct comedi_subdevice *s = dev->read_subdev;
                struct comedi_cmd *cmd = &s->async->cmd;

                for (i = 0; i < cmd->chanlist_len; i++) {
                        /* read data */
                        lsb = dmm_inb(dev, DMM32AT_AILSB);
                        msb = dmm_inb(dev, DMM32AT_AIMSB);

                        /* invert sign bit to make range unsigned */
                        samp = ((msb ^ 0x0080) << 8) + lsb;
                        comedi_buf_put(s->async, samp);
                }

                if (devpriv->ai_scans_left != 0xffffffff) {     /* TRIG_COUNT */
                        devpriv->ai_scans_left--;
                        if (devpriv->ai_scans_left == 0) {
                                /* disable further interrupts and clocks */
                                dmm_outb(dev, DMM32AT_INTCLOCK, 0x0);
                                /* set the buffer to be flushed with an EOF */
                                s->async->events |= COMEDI_CB_EOA;
                        }

                }
                /* flush the buffer */
                comedi_event(dev, s);
        }

        /* reset the interrupt */
        dmm_outb(dev, DMM32AT_CNTRL, DMM32AT_INTRESET);
        return IRQ_HANDLED;
}

/* This function doesn't require a particular form, this is just
 * what happens to be used in some of the drivers.  It should
 * convert ns nanoseconds to a counter value suitable for programming
 * the device.  Also, it should adjust ns so that it cooresponds to
 * the actual time that the device will use. */
static int dmm32at_ns_to_timer(unsigned int *ns, int round)
{
        /* trivial timer */
        /* if your timing is done through two cascaded timers, the
         * i8253_cascade_ns_to_timer() function in 8253.h can be
         * very helpful.  There are also i8254_load() and i8254_mm_load()
         * which can be used to load values into the ubiquitous 8254 counters
         */

        return *ns;
}

static int dmm32at_ao_winsn(struct comedi_device *dev,
                            struct comedi_subdevice *s,
                            struct comedi_insn *insn, unsigned int *data)
{
        int i;
        int chan = CR_CHAN(insn->chanspec);
        unsigned char hi, lo, status;

        /* Writing a list of values to an AO channel is probably not
         * very useful, but that's how the interface is defined. */
        for (i = 0; i < insn->n; i++) {

                devpriv->ao_readback[chan] = data[i];

                /* get the low byte */
                lo = data[i] & 0x00ff;
                /* high byte also contains channel number */
                hi = (data[i] >> 8) + chan * (1 << 6);
                /* printk("writing 0x%02x  0x%02x\n",hi,lo); */
                /* write the low and high values to the board */
                dmm_outb(dev, DMM32AT_DACLSB, lo);
                dmm_outb(dev, DMM32AT_DACMSB, hi);

                /* wait for circuit to settle */
                for (i = 0; i < 40000; i++) {
                        status = dmm_inb(dev, DMM32AT_DACSTAT);
                        if ((status & DMM32AT_DACBUSY) == 0)
                                break;
                }
                if (i == 40000) {
                        printk("timeout\n");
                        return -ETIMEDOUT;
                }
                /* dummy read to update trigger the output */
                status = dmm_inb(dev, DMM32AT_DACMSB);

        }

        /* return the number of samples read/written */
        return i;
}

/* AO subdevices should have a read insn as well as a write insn.
 * Usually this means copying a value stored in devpriv. */
static int dmm32at_ao_rinsn(struct comedi_device *dev,
                            struct comedi_subdevice *s,
                            struct comedi_insn *insn, unsigned int *data)
{
        int i;
        int chan = CR_CHAN(insn->chanspec);

        for (i = 0; i < insn->n; i++)
                data[i] = devpriv->ao_readback[chan];

        return i;
}

/* DIO devices are slightly special.  Although it is possible to
 * implement the insn_read/insn_write interface, it is much more
 * useful to applications if you implement the insn_bits interface.
 * This allows packed reading/writing of the DIO channels.  The
 * comedi core can convert between insn_bits and insn_read/write */
static int dmm32at_dio_insn_bits(struct comedi_device *dev,
                                 struct comedi_subdevice *s,
                                 struct comedi_insn *insn, unsigned int *data)
{
        unsigned char diobits;

        if (insn->n != 2)
                return -EINVAL;

        /* The insn data is a mask in data[0] and the new data
         * in data[1], each channel cooresponding to a bit. */
        if (data[0]) {
                s->state &= ~data[0];
                s->state |= data[0] & data[1];
                /* Write out the new digital output lines */
                /* outw(s->state,dev->iobase + DMM32AT_DIO); */
        }

        /* get access to the DIO regs */
        dmm_outb(dev, DMM32AT_CNTRL, DMM32AT_DIOACC);

        /* if either part of dio is set for output */
        if (((devpriv->dio_config & DMM32AT_DIRCL) == 0) ||
            ((devpriv->dio_config & DMM32AT_DIRCH) == 0)) {
                diobits = (s->state & 0x00ff0000) >> 16;
                dmm_outb(dev, DMM32AT_DIOC, diobits);
        }
        if ((devpriv->dio_config & DMM32AT_DIRB) == 0) {
                diobits = (s->state & 0x0000ff00) >> 8;

                dmm_outb(dev, DMM32AT_DIOB, diobits);
        }
        if ((devpriv->dio_config & DMM32AT_DIRA) == 0) {
                diobits = (s->state & 0x000000ff);
                dmm_outb(dev, DMM32AT_DIOA, diobits);
        }

        /* now read the state back in */
        s->state = dmm_inb(dev, DMM32AT_DIOC);
        s->state <<= 8;
        s->state |= dmm_inb(dev, DMM32AT_DIOB);
        s->state <<= 8;
        s->state |= dmm_inb(dev, DMM32AT_DIOA);
        data[1] = s->state;

        /* on return, data[1] contains the value of the digital
         * input and output lines. */
        /* data[1]=inw(dev->iobase + DMM32AT_DIO); */
        /* or we could just return the software copy of the output values if
         * it was a purely digital output subdevice */
        /* data[1]=s->state; */

        return 2;
}

static int dmm32at_dio_insn_config(struct comedi_device *dev,
                                   struct comedi_subdevice *s,
                                   struct comedi_insn *insn, unsigned int *data)
{
        unsigned char chanbit;
        int chan = CR_CHAN(insn->chanspec);

        if (insn->n != 1)
                return -EINVAL;

        if (chan < 8)
                chanbit = DMM32AT_DIRA;
        else if (chan < 16)
                chanbit = DMM32AT_DIRB;
        else if (chan < 20)
                chanbit = DMM32AT_DIRCL;
        else
                chanbit = DMM32AT_DIRCH;

        /* The input or output configuration of each digital line is
         * configured by a special insn_config instruction.  chanspec
         * contains the channel to be changed, and data[0] contains the
         * value COMEDI_INPUT or COMEDI_OUTPUT. */

        /* if output clear the bit, otherwise set it */
        if (data[0] == COMEDI_OUTPUT) {
                devpriv->dio_config &= ~chanbit;
        } else {
                devpriv->dio_config |= chanbit;
        }
        /* get access to the DIO regs */
        dmm_outb(dev, DMM32AT_CNTRL, DMM32AT_DIOACC);
        /* set the DIO's to the new configuration setting */
        dmm_outb(dev, DMM32AT_DIOCONF, devpriv->dio_config);

        return 1;
}

void dmm32at_setaitimer(struct comedi_device *dev, unsigned int nansec)
{
        unsigned char lo1, lo2, hi2;
        unsigned short both2;

        /* based on 10mhz clock */
        lo1 = 200;
        both2 = nansec / 20000;
        hi2 = (both2 & 0xff00) >> 8;
        lo2 = both2 & 0x00ff;

        /* set the counter frequency to 10mhz */
        dmm_outb(dev, DMM32AT_CNTRDIO, 0);

        /* get access to the clock regs */
        dmm_outb(dev, DMM32AT_CNTRL, DMM32AT_CLKACC);

        /* write the counter 1 control word and low byte to counter */
        dmm_outb(dev, DMM32AT_CLKCT, DMM32AT_CLKCT1);
        dmm_outb(dev, DMM32AT_CLK1, lo1);

        /* write the counter 2 control word and low byte then to counter */
        dmm_outb(dev, DMM32AT_CLKCT, DMM32AT_CLKCT2);
        dmm_outb(dev, DMM32AT_CLK2, lo2);
        dmm_outb(dev, DMM32AT_CLK2, hi2);

        /* enable the ai conversion interrupt and the clock to start scans */
        dmm_outb(dev, DMM32AT_INTCLOCK, DMM32AT_ADINT | DMM32AT_CLKSEL);

}

/*
 * A convenient macro that defines init_module() and cleanup_module(),
 * as necessary.
 */
COMEDI_INITCLEANUP(driver_dmm32at);