kcomedilib_main.c

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/*
    kcomedilib/kcomedilib.c
    a comedlib interface for kernel modules

    COMEDI - Linux Control and Measurement Device Interface
    Copyright (C) 1997-2000 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.

*/

#define __NO_VERSION__
#include <linux/module.h>

#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/fcntl.h>
#include <linux/delay.h>
#include <linux/ioport.h>
#include <linux/mm.h>
#include <linux/io.h>

#include "../comedi.h"
#include "../comedilib.h"
#include "../comedidev.h"

MODULE_AUTHOR("David Schleef <[email protected]>");
MODULE_DESCRIPTION("Comedi kernel library");
MODULE_LICENSE("GPL");

struct comedi_device *comedi_open(const char *filename)
{
    struct comedi_device_file_info *dev_file_info;
    struct comedi_device *dev;
    unsigned int minor;

    if (strncmp(filename, "/dev/comedi", 11) != 0)
        return NULL;

    minor = simple_strtoul(filename + 11, NULL, 0);

    if (minor >= COMEDI_NUM_BOARD_MINORS)
        return NULL;

    dev_file_info = comedi_get_device_file_info(minor);
    if (dev_file_info == NULL)
        return NULL;
    dev = dev_file_info->device;

    if (dev == NULL || !dev->attached)
        return NULL;

    if (!try_module_get(dev->driver->module))
        return NULL;

    return dev;
}
EXPORT_SYMBOL(comedi_open);

int comedi_close(struct comedi_device *d)
{
    struct comedi_device *dev = (struct comedi_device *)d;

    module_put(dev->driver->module);

    return 0;
}
EXPORT_SYMBOL(comedi_close);

static int comedi_do_insn(struct comedi_device *dev,
              struct comedi_insn *insn,
              unsigned int *data)
{
    struct comedi_subdevice *s;
    int ret = 0;

    /* a subdevice instruction */
    if (insn->subdev >= dev->n_subdevices) {
        ret = -EINVAL;
        goto error;
    }
    s = &dev->subdevices[insn->subdev];

    if (s->type == COMEDI_SUBD_UNUSED) {
        printk(KERN_ERR "%d not useable subdevice\n", insn->subdev);
        ret = -EIO;
        goto error;
    }

    /* XXX check lock */

    ret = comedi_check_chanlist(s, 1, &insn->chanspec);
    if (ret < 0) {
        printk(KERN_ERR "bad chanspec\n");
        ret = -EINVAL;
        goto error;
    }

    if (s->busy) {
        ret = -EBUSY;
        goto error;
    }
    s->busy = dev;

    switch (insn->insn) {
    case INSN_BITS:
        ret = s->insn_bits(dev, s, insn, data);
        break;
    case INSN_CONFIG:
        /* XXX should check instruction length */
        ret = s->insn_config(dev, s, insn, data);
        break;
    default:
        ret = -EINVAL;
        break;
    }

    s->busy = NULL;
error:

    return ret;
}

int comedi_dio_config(struct comedi_device *dev, unsigned int subdev,
              unsigned int chan, unsigned int io)
{
    struct comedi_insn insn;

    memset(&insn, 0, sizeof(insn));
    insn.insn = INSN_CONFIG;
    insn.n = 1;
    insn.subdev = subdev;
    insn.chanspec = CR_PACK(chan, 0, 0);

    return comedi_do_insn(dev, &insn, &io);
}
EXPORT_SYMBOL(comedi_dio_config);

int comedi_dio_bitfield(struct comedi_device *dev, unsigned int subdev,
            unsigned int mask, unsigned int *bits)
{
    struct comedi_insn insn;
    unsigned int data[2];
    int ret;

    memset(&insn, 0, sizeof(insn));
    insn.insn = INSN_BITS;
    insn.n = 2;
    insn.subdev = subdev;

    data[0] = mask;
    data[1] = *bits;

    ret = comedi_do_insn(dev, &insn, data);

    *bits = data[1];

    return ret;
}
EXPORT_SYMBOL(comedi_dio_bitfield);

int comedi_find_subdevice_by_type(struct comedi_device *dev, int type,
                  unsigned int subd)
{
    struct comedi_subdevice *s;

    if (subd > dev->n_subdevices)
        return -ENODEV;

    for (; subd < dev->n_subdevices; subd++) {
        s = &dev->subdevices[subd];
        if (s->type == type)
            return subd;
    }
    return -1;
}
EXPORT_SYMBOL(comedi_find_subdevice_by_type);

int comedi_get_n_channels(struct comedi_device *dev, unsigned int subdevice)
{
    struct comedi_subdevice *s = &dev->subdevices[subdevice];

    return s->n_chan;
}
EXPORT_SYMBOL(comedi_get_n_channels);