/*
   Some comments on the code..

   - it shouldn't be necessary to use outb_p().

   - ignoreirq creates a race condition.  It needs to be fixed.

 */

/*
   comedi/drivers/das6402.c
   An experimental driver for Computerboards' DAS6402 I/O card

   Copyright (C) 1999 Oystein Svendsen <svendsen@pvv.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: das6402
Description: Keithley Metrabyte DAS6402 (& compatibles)
Author: Oystein Svendsen <svendsen@pvv.org>
Status: bitrotten
Devices: [Keithley Metrabyte] DAS6402 (das6402)

This driver has suffered bitrot.
*/

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

#include <linux/ioport.h>

#define DAS6402_SIZE 16

#define N_WORDS 3000*64

#define STOP    0
#define START   1

#define SCANL 0x3f00
#define BYTE unsigned char
#define WORD unsigned short

/*----- register 8 ----*/
#define CLRINT 0x01
#define CLRXTR 0x02
#define CLRXIN 0x04
#define EXTEND 0x10
#define ARMED 0x20              /* enable conting of post sample conv */
#define POSTMODE 0x40
#define MHZ 0x80                /* 10 MHz clock */
/*---------------------*/

/*----- register 9 ----*/
#define IRQ (0x04 << 4)         /* these two are                         */
#define IRQV 10                 /*               dependent on each other */

#define CONVSRC 0x03            /* trig src is Intarnal pacer */
#define BURSTEN 0x04            /* enable burst */
#define XINTE 0x08              /* use external int. trig */
#define INTE 0x80               /* enable analog interrupts */
/*---------------------*/

/*----- register 10 ---*/
#define TGEN 0x01               /* Use pin DI1 for externl trigging? */
#define TGSEL 0x02              /* Use edge triggering */
#define TGPOL 0x04              /* active edge is falling */
#define PRETRIG 0x08            /* pretrig */
/*---------------------*/

/*----- register 11 ---*/
#define EOB 0x0c
#define FIFOHFULL 0x08
#define GAIN 0x01
#define FIFONEPTY 0x04
#define MODE 0x10
#define SEM 0x20
#define BIP 0x40
/*---------------------*/

#define M0 0x00
#define M2 0x04

#define C0 0x00
#define C1 0x40
#define C2 0x80
#define RWLH 0x30

static int das6402_attach(struct comedi_device *dev,
                          struct comedi_devconfig *it);
static int das6402_detach(struct comedi_device *dev);
static struct comedi_driver driver_das6402 = {
        .driver_name = "das6402",
        .module = THIS_MODULE,
        .attach = das6402_attach,
        .detach = das6402_detach,
};

COMEDI_INITCLEANUP(driver_das6402);

struct das6402_private {
        int ai_bytes_to_read;

        int das6402_ignoreirq;
};
#define devpriv ((struct das6402_private *)dev->private)

static void das6402_ai_fifo_dregs(struct comedi_device *dev,
                                  struct comedi_subdevice *s);

static void das6402_setcounter(struct comedi_device *dev)
{
        BYTE p;
        unsigned short ctrlwrd;

        /* set up counter0 first, mode 0 */
        p = M0 | C0 | RWLH;
        outb_p(p, dev->iobase + 15);
        ctrlwrd = 2000;
        p = (BYTE) (0xff & ctrlwrd);
        outb_p(p, dev->iobase + 12);
        p = (BYTE) (0xff & (ctrlwrd >> 8));
        outb_p(p, dev->iobase + 12);

        /* set up counter1, mode 2 */
        p = M2 | C1 | RWLH;
        outb_p(p, dev->iobase + 15);
        ctrlwrd = 10;
        p = (BYTE) (0xff & ctrlwrd);
        outb_p(p, dev->iobase + 13);
        p = (BYTE) (0xff & (ctrlwrd >> 8));
        outb_p(p, dev->iobase + 13);

        /* set up counter1, mode 2 */
        p = M2 | C2 | RWLH;
        outb_p(p, dev->iobase + 15);
        ctrlwrd = 1000;
        p = (BYTE) (0xff & ctrlwrd);
        outb_p(p, dev->iobase + 14);
        p = (BYTE) (0xff & (ctrlwrd >> 8));
        outb_p(p, dev->iobase + 14);
}

static irqreturn_t intr_handler(int irq, void *d)
{
        struct comedi_device *dev = d;
        struct comedi_subdevice *s = dev->subdevices;

        if (!dev->attached || devpriv->das6402_ignoreirq) {
                printk("das6402: BUG: spurious interrupt\n");
                return IRQ_HANDLED;
        }
#ifdef DEBUG
        printk("das6402: interrupt! das6402_irqcount=%i\n",
               devpriv->das6402_irqcount);
        printk("das6402: iobase+2=%i\n", inw_p(dev->iobase + 2));
#endif

        das6402_ai_fifo_dregs(dev, s);

        if (s->async->buf_write_count >= devpriv->ai_bytes_to_read) {
                outw_p(SCANL, dev->iobase + 2); /* clears the fifo */
                outb(0x07, dev->iobase + 8);    /* clears all flip-flops */
#ifdef DEBUG
                printk("das6402: Got %i samples\n\n",
                       devpriv->das6402_wordsread - diff);
#endif
                s->async->events |= COMEDI_CB_EOA;
                comedi_event(dev, s);
        }

        outb(0x01, dev->iobase + 8);    /* clear only the interrupt flip-flop */

        comedi_event(dev, s);
        return IRQ_HANDLED;
}

#if 0
static void das6402_ai_fifo_read(struct comedi_device *dev, short *data, int n)
{
        int i;

        for (i = 0; i < n; i++)
                data[i] = inw(dev->iobase);
}
#endif

static void das6402_ai_fifo_dregs(struct comedi_device *dev,
                                  struct comedi_subdevice *s)
{
        while (1) {
                if (!(inb(dev->iobase + 8) & 0x01))
                        return;
                comedi_buf_put(s->async, inw(dev->iobase));
        }
}

static int das6402_ai_cancel(struct comedi_device *dev,
                             struct comedi_subdevice *s)
{
        /*
         *  This function should reset the board from whatever condition it
         *  is in (i.e., acquiring data), to a non-active state.
         */

        devpriv->das6402_ignoreirq = 1;
#ifdef DEBUG
        printk("das6402: Stopping acquisition\n");
#endif
        devpriv->das6402_ignoreirq = 1;
        outb_p(0x02, dev->iobase + 10); /* disable external trigging */
        outw_p(SCANL, dev->iobase + 2); /* resets the card fifo */
        outb_p(0, dev->iobase + 9);     /* disables interrupts */

        outw_p(SCANL, dev->iobase + 2);

        return 0;
}

#ifdef unused
static int das6402_ai_mode2(struct comedi_device *dev,
                            struct comedi_subdevice *s, comedi_trig * it)
{
        devpriv->das6402_ignoreirq = 1;

#ifdef DEBUG
        printk("das6402: Starting acquisition\n");
#endif
        outb_p(0x03, dev->iobase + 10); /* enable external trigging */
        outw_p(SCANL, dev->iobase + 2); /* resets the card fifo */
        outb_p(IRQ | CONVSRC | BURSTEN | INTE, dev->iobase + 9);

        devpriv->ai_bytes_to_read = it->n * sizeof(short);

        /* um... ignoreirq is a nasty race condition */
        devpriv->das6402_ignoreirq = 0;

        outw_p(SCANL, dev->iobase + 2);

        return 0;
}
#endif

static int board_init(struct comedi_device *dev)
{
        BYTE b;

        devpriv->das6402_ignoreirq = 1;

        outb(0x07, dev->iobase + 8);

        /* register 11  */
        outb_p(MODE, dev->iobase + 11);
        b = BIP | SEM | MODE | GAIN | FIFOHFULL;
        outb_p(b, dev->iobase + 11);

        /* register 8   */
        outb_p(EXTEND, dev->iobase + 8);
        b = EXTEND | MHZ;
        outb_p(b, dev->iobase + 8);
        b = MHZ | CLRINT | CLRXTR | CLRXIN;
        outb_p(b, dev->iobase + 8);

        /* register 9    */
        b = IRQ | CONVSRC | BURSTEN | INTE;
        outb_p(b, dev->iobase + 9);

        /* register 10   */
        b = TGSEL | TGEN;
        outb_p(b, dev->iobase + 10);

        b = 0x07;
        outb_p(b, dev->iobase + 8);

        das6402_setcounter(dev);

        outw_p(SCANL, dev->iobase + 2); /* reset card fifo */

        devpriv->das6402_ignoreirq = 0;

        return 0;
}

static int das6402_detach(struct comedi_device *dev)
{
        if (dev->irq)
                free_irq(dev->irq, dev);
        if (dev->iobase)
                release_region(dev->iobase, DAS6402_SIZE);

        return 0;
}

static int das6402_attach(struct comedi_device *dev,
                          struct comedi_devconfig *it)
{
        unsigned int irq;
        unsigned long iobase;
        int ret;
        struct comedi_subdevice *s;

        dev->board_name = "das6402";

        iobase = it->options[0];
        if (iobase == 0)
                iobase = 0x300;

        printk("comedi%d: das6402: 0x%04lx", dev->minor, iobase);

        if (!request_region(iobase, DAS6402_SIZE, "das6402")) {
                printk(" I/O port conflict\n");
                return -EIO;
        }
        dev->iobase = iobase;

        /* should do a probe here */

        irq = it->options[0];
        printk(" ( irq = %u )", irq);
        ret = request_irq(irq, intr_handler, 0, "das6402", dev);
        if (ret < 0) {
                printk("irq conflict\n");
                return ret;
        }
        dev->irq = irq;

        ret = alloc_private(dev, sizeof(struct das6402_private));
        if (ret < 0)
                return ret;

        ret = alloc_subdevices(dev, 1);
        if (ret < 0)
                return ret;

        /* ai subdevice */
        s = dev->subdevices + 0;
        s->type = COMEDI_SUBD_AI;
        s->subdev_flags = SDF_READABLE | SDF_GROUND;
        s->n_chan = 8;
        /* s->trig[2]=das6402_ai_mode2; */
        s->cancel = das6402_ai_cancel;
        s->maxdata = (1 << 12) - 1;
        s->len_chanlist = 16;   /* ? */
        s->range_table = &range_unknown;

        board_init(dev);

        return 0;
}