pcmad.c

Go to the documentation of this file.

/*
    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 <[email protected]>

    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 <linux/interrupt.h>
#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;
};

struct pcmad_priv_struct {
    int differential;
    int twos_comp;
};
#define devpriv ((struct pcmad_priv_struct *)dev->private)

#define TIMEOUT 100

static int pcmad_ai_insn_read(struct comedi_device *dev,
                  struct comedi_subdevice *s,
                  struct comedi_insn *insn, unsigned int *data)
{
    const struct pcmad_board_struct *board = comedi_board(dev);
    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 << (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(struct comedi_device *dev, struct comedi_devconfig *it)
{
    const struct pcmad_board_struct *board = comedi_board(dev);
    int ret;
    struct comedi_subdevice *s;
    unsigned long iobase;

    iobase = it->options[0];
    printk(KERN_INFO "comedi%d: pcmad: 0x%04lx ", dev->minor, iobase);
    if (!request_region(iobase, PCMAD_SIZE, "pcmad")) {
        printk(KERN_CONT "I/O port conflict\n");
        return -EIO;
    }
    printk(KERN_CONT "\n");
    dev->iobase = iobase;

    ret = comedi_alloc_subdevices(dev, 1);
    if (ret)
        return ret;

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

    dev->board_name = 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 << board->n_ai_bits) - 1;
    s->range_table = &range_unknown;

    return 0;
}

static void pcmad_detach(struct comedi_device *dev)
{
    if (dev->irq)
        free_irq(dev->irq, dev);
    if (dev->iobase)
        release_region(dev->iobase, PCMAD_SIZE);
}

static const struct pcmad_board_struct pcmad_boards[] = {
    {
        .name       = "pcmad12",
        .n_ai_bits  = 12,
    }, {
        .name       = "pcmad16",
        .n_ai_bits  = 16,
    },
};
static struct comedi_driver pcmad_driver = {
    .driver_name    = "pcmad",
    .module     = THIS_MODULE,
    .attach     = pcmad_attach,
    .detach     = pcmad_detach,
    .board_name = &pcmad_boards[0].name,
    .num_names  = ARRAY_SIZE(pcmad_boards),
    .offset     = sizeof(pcmad_boards[0]),
};
module_comedi_driver(pcmad_driver);

MODULE_AUTHOR("Comedi http://www.comedi.org");
MODULE_DESCRIPTION("Comedi low-level driver");
MODULE_LICENSE("GPL");