Staging: comedi: add pcmad driver

/*

    comedi/drivers/pcmad.c

    Hardware driver for Winsystems PCM-A/D12 and PCM-A/D16

    COMEDI - Linux Control and Measurement Device Interface

    Copyright (C) 2000,2001 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: pcmad

Description: Winsystems PCM-A/D12, PCM-A/D16

Author: ds

Devices: [Winsystems] PCM-A/D12 (pcmad12), PCM-A/D16 (pcmad16)

Status: untested

This driver was written on a bet that I couldn't write a driver

in less than 2 hours.  I won the bet, but never got paid.  =(

Configuration options:

  [0] - I/O port base

  [1] - unused

  [2] - Analog input reference

          0 = single ended

          1 = differential

  [3] - Analog input encoding (must match jumpers)

          0 = straight binary

          1 = two's complement

*/

#include "../comedidev.h"

#include <linux/ioport.h>

#define PCMAD_SIZE		4

#define PCMAD_STATUS		0

#define PCMAD_LSB		1

#define PCMAD_MSB		2

#define PCMAD_CONVERT		1

struct pcmad_board_struct {

	const char *name;

	int n_ai_bits;

};

static const struct pcmad_board_struct pcmad_boards[] = {

	{

	      name:	"pcmad12",

	      n_ai_bits:12,

		},

	{

	      name:	"pcmad16",

	      n_ai_bits:16,

		},

};

#define this_board ((const struct pcmad_board_struct *)(dev->board_ptr))

#define n_pcmad_boards (sizeof(pcmad_boards)/sizeof(pcmad_boards[0]))

struct pcmad_priv_struct {

	int differential;

	int twos_comp;

};

#define devpriv ((struct pcmad_priv_struct *)dev->private)

static int pcmad_attach(comedi_device * dev, comedi_devconfig * it);

static int pcmad_detach(comedi_device * dev);

static comedi_driver driver_pcmad = {

      driver_name:"pcmad",

      module:THIS_MODULE,

      attach:pcmad_attach,

      detach:pcmad_detach,

      board_name:&pcmad_boards[0].name,

      num_names:n_pcmad_boards,

      offset:sizeof(pcmad_boards[0]),

};

COMEDI_INITCLEANUP(driver_pcmad);

#define TIMEOUT	100

static int pcmad_ai_insn_read(comedi_device * dev, comedi_subdevice * s,

	comedi_insn * insn, lsampl_t * data)

{

	int i;

	int chan;

	int n;

	chan = CR_CHAN(insn->chanspec);

	for (n = 0; n < insn->n; n++) {

		outb(chan, dev->iobase + PCMAD_CONVERT);

		for (i = 0; i < TIMEOUT; i++) {

			if ((inb(dev->iobase + PCMAD_STATUS) & 0x3) == 0x3)

				break;

		}

		data[n] = inb(dev->iobase + PCMAD_LSB);

		data[n] |= (inb(dev->iobase + PCMAD_MSB) << 8);

		if (devpriv->twos_comp) {

			data[n] ^= (1 << (this_board->n_ai_bits - 1));

		}

	}

	return n;

}

/*

 * options:

 * 0	i/o base

 * 1	unused

 * 2	0=single ended 1=differential

 * 3	0=straight binary 1=two's comp

 */

static int pcmad_attach(comedi_device * dev, comedi_devconfig * it)

{

	int ret;

	comedi_subdevice *s;

	unsigned long iobase;

	iobase = it->options[0];

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

	if (!request_region(iobase, PCMAD_SIZE, "pcmad")) {

		printk("I/O port conflict\n");

		return -EIO;

	}

	dev->iobase = iobase;

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

		return ret;

	if ((ret = alloc_private(dev, sizeof(struct pcmad_priv_struct))) < 0)

		return ret;

	dev->board_name = this_board->name;

	s = dev->subdevices + 0;

	s->type = COMEDI_SUBD_AI;

	s->subdev_flags = SDF_READABLE | AREF_GROUND;

	s->n_chan = 16;		/* XXX */

	s->len_chanlist = 1;

	s->insn_read = pcmad_ai_insn_read;

	s->maxdata = (1 << this_board->n_ai_bits) - 1;

	s->range_table = &range_unknown;

	return 0;

}

static int pcmad_detach(comedi_device * dev)

{

	printk("comedi%d: pcmad: remove\n", dev->minor);

	if (dev->irq) {

		free_irq(dev->irq, dev);

	}

	if (dev->iobase)

		release_region(dev->iobase, PCMAD_SIZE);

	return 0;

}