comedi/comedi/drivers/pcmad.c

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/*
    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 <linux/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;
}