/*
   Some comments on the code..

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

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


 */

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

typedef struct{
	int ai_bytes_to_read;

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


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

static void das6402_setcounter(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 void intr_handler(int irq,void *d,struct pt_regs *regs)
{
	comedi_device *dev=d;
	comedi_subdevice *s=dev->subdevices;

	if (devpriv->das6402_ignoreirq){
		printk("das6402: BUG: spurious interrupt\n");
		return;
	}

#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,s->async->events);
	}

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

	comedi_event(dev,s,s->async->events);
}

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

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


static void das6402_ai_fifo_dregs(comedi_device *dev,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(comedi_device *dev,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(comedi_device *dev,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(sampl_t);

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

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

	return 0;
}
#endif


static int board_init(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(comedi_device *dev)
{
        if(dev->irq)comedi_free_irq(dev->irq,dev);
	if(dev->iobase)release_region(dev->iobase,DAS6402_SIZE);

	return 0;
}

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

	dev->board_name="das6402";

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

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

	if(check_region(iobase,DAS6402_SIZE)<0){
		printk(" I/O port conflict\n");
		return -EIO;
	}
	request_region(iobase,DAS6402_SIZE,"das6402");
	dev->iobase=iobase;

	/* should do a probe here */

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

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

	dev->n_subdevices=1;
	if((ret=alloc_subdevices(dev))<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;
}