comedi_parport.c

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/*
    comedi/drivers/comedi_parport.c
    hardware driver for standard parallel port

    COMEDI - Linux Control and Measurement Device Interface
    Copyright (C) 1998,2001 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: comedi_parport
Description: Standard PC parallel port
Author: ds
Status: works in immediate mode
Devices: [standard] parallel port (comedi_parport)
Updated: Tue, 30 Apr 2002 21:11:45 -0700

A cheap and easy way to get a few more digital I/O lines.  Steal
additional parallel ports from old computers or your neighbors'
computers.

Option list:
 0: I/O port base for the parallel port.
 1: IRQ

Parallel Port Lines:

pin     subdev  chan    aka
---     ------  ----    ---
1       2       0       strobe
2       0       0       data 0
3       0       1       data 1
4       0       2       data 2
5       0       3       data 3
6       0       4       data 4
7       0       5       data 5
8       0       6       data 6
9       0       7       data 7
10      1       3       acknowledge
11      1       4       busy
12      1       2       output
13      1       1       printer selected
14      2       1       auto LF
15      1       0       error
16      2       2       init
17      2       3       select printer
18-25   ground

Notes:

Subdevices 0 is digital I/O, subdevice 1 is digital input, and
subdevice 2 is digital output.  Unlike other Comedi devices,
subdevice 0 defaults to output.

Pins 13 and 14 are inverted once by Comedi and once by the
hardware, thus cancelling the effect.

Pin 1 is a strobe, thus acts like one.  There's no way in software
to change this, at least on a standard parallel port.

Subdevice 3 pretends to be a digital input subdevice, but it always
returns 0 when read.  However, if you run a command with
scan_begin_src=TRIG_EXT, it uses pin 10 as a external triggering
pin, which can be used to wake up tasks.
*/
/*
   see http://www.beyondlogic.org/ for information.
   or http://www.linux-magazin.de/ausgabe/1999/10/IO/io.html
 */

#include "../comedidev.h"
#include <linux/interrupt.h>
#include <linux/ioport.h>

#include "comedi_fc.h"

#define PARPORT_SIZE 3

#define PARPORT_A 0
#define PARPORT_B 1
#define PARPORT_C 2

struct parport_private {
    unsigned int a_data;
    unsigned int c_data;
    int enable_irq;
};

static int parport_insn_a(struct comedi_device *dev, struct comedi_subdevice *s,
              struct comedi_insn *insn, unsigned int *data)
{
    struct parport_private *devpriv = dev->private;

    if (data[0]) {
        devpriv->a_data &= ~data[0];
        devpriv->a_data |= (data[0] & data[1]);

        outb(devpriv->a_data, dev->iobase + PARPORT_A);
    }

    data[1] = inb(dev->iobase + PARPORT_A);

    return insn->n;
}

static int parport_insn_config_a(struct comedi_device *dev,
                 struct comedi_subdevice *s,
                 struct comedi_insn *insn, unsigned int *data)
{
    struct parport_private *devpriv = dev->private;

    if (data[0]) {
        s->io_bits = 0xff;
        devpriv->c_data &= ~(1 << 5);
    } else {
        s->io_bits = 0;
        devpriv->c_data |= (1 << 5);
    }
    outb(devpriv->c_data, dev->iobase + PARPORT_C);

    return 1;
}

static int parport_insn_b(struct comedi_device *dev, struct comedi_subdevice *s,
              struct comedi_insn *insn, unsigned int *data)
{
    if (data[0]) {
        /* should writes be ignored? */
        /* anyone??? */
    }

    data[1] = (inb(dev->iobase + PARPORT_B) >> 3);

    return insn->n;
}

static int parport_insn_c(struct comedi_device *dev, struct comedi_subdevice *s,
              struct comedi_insn *insn, unsigned int *data)
{
    struct parport_private *devpriv = dev->private;

    data[0] &= 0x0f;
    if (data[0]) {
        devpriv->c_data &= ~data[0];
        devpriv->c_data |= (data[0] & data[1]);

        outb(devpriv->c_data, dev->iobase + PARPORT_C);
    }

    data[1] = devpriv->c_data & 0xf;

    return insn->n;
}

static int parport_intr_insn(struct comedi_device *dev,
                 struct comedi_subdevice *s,
                 struct comedi_insn *insn, unsigned int *data)
{
    data[1] = 0;
    return insn->n;
}

static int parport_intr_cmdtest(struct comedi_device *dev,
                struct comedi_subdevice *s,
                struct comedi_cmd *cmd)
{
    int err = 0;

    /* Step 1 : check if triggers are trivially valid */

    err |= cfc_check_trigger_src(&cmd->start_src, TRIG_NOW);
    err |= cfc_check_trigger_src(&cmd->scan_begin_src, TRIG_EXT);
    err |= cfc_check_trigger_src(&cmd->convert_src, TRIG_FOLLOW);
    err |= cfc_check_trigger_src(&cmd->scan_end_src, TRIG_COUNT);
    err |= cfc_check_trigger_src(&cmd->stop_src, TRIG_NONE);

    if (err)
        return 1;

    /* Step 2a : make sure trigger sources are unique */
    /* Step 2b : and mutually compatible */

    if (err)
        return 2;

    /* step 3: */

    if (cmd->start_arg != 0) {
        cmd->start_arg = 0;
        err++;
    }
    if (cmd->scan_begin_arg != 0) {
        cmd->scan_begin_arg = 0;
        err++;
    }
    if (cmd->convert_arg != 0) {
        cmd->convert_arg = 0;
        err++;
    }
    if (cmd->scan_end_arg != 1) {
        cmd->scan_end_arg = 1;
        err++;
    }
    if (cmd->stop_arg != 0) {
        cmd->stop_arg = 0;
        err++;
    }

    if (err)
        return 3;

    /* step 4: ignored */

    if (err)
        return 4;

    return 0;
}

static int parport_intr_cmd(struct comedi_device *dev,
                struct comedi_subdevice *s)
{
    struct parport_private *devpriv = dev->private;

    devpriv->c_data |= 0x10;
    outb(devpriv->c_data, dev->iobase + PARPORT_C);

    devpriv->enable_irq = 1;

    return 0;
}

static int parport_intr_cancel(struct comedi_device *dev,
                   struct comedi_subdevice *s)
{
    struct parport_private *devpriv = dev->private;

    devpriv->c_data &= ~0x10;
    outb(devpriv->c_data, dev->iobase + PARPORT_C);

    devpriv->enable_irq = 0;

    return 0;
}

static irqreturn_t parport_interrupt(int irq, void *d)
{
    struct comedi_device *dev = d;
    struct parport_private *devpriv = dev->private;
    struct comedi_subdevice *s = &dev->subdevices[3];

    if (!devpriv->enable_irq)
        return IRQ_NONE;

    comedi_buf_put(s->async, 0);
    s->async->events |= COMEDI_CB_BLOCK | COMEDI_CB_EOS;

    comedi_event(dev, s);
    return IRQ_HANDLED;
}

static int parport_attach(struct comedi_device *dev,
              struct comedi_devconfig *it)
{
    struct parport_private *devpriv;
    int ret;
    unsigned int irq;
    unsigned long iobase;
    struct comedi_subdevice *s;

    dev->board_name = dev->driver->driver_name;

    iobase = it->options[0];
    if (!request_region(iobase, PARPORT_SIZE, dev->board_name)) {
        dev_err(dev->class_dev, "I/O port conflict\n");
        return -EIO;
    }
    dev->iobase = iobase;

    irq = it->options[1];
    if (irq) {
        ret = request_irq(irq, parport_interrupt, 0, dev->board_name,
                  dev);
        if (ret < 0) {
            dev_err(dev->class_dev, "irq not available\n");
            return -EINVAL;
        }
        dev->irq = irq;
    }

    ret = comedi_alloc_subdevices(dev, 4);
    if (ret)
        return ret;

    ret = alloc_private(dev, sizeof(*devpriv));
    if (ret < 0)
        return ret;
    devpriv = dev->private;

    s = &dev->subdevices[0];
    s->type = COMEDI_SUBD_DIO;
    s->subdev_flags = SDF_READABLE | SDF_WRITABLE;
    s->n_chan = 8;
    s->maxdata = 1;
    s->range_table = &range_digital;
    s->insn_bits = parport_insn_a;
    s->insn_config = parport_insn_config_a;

    s = &dev->subdevices[1];
    s->type = COMEDI_SUBD_DI;
    s->subdev_flags = SDF_READABLE;
    s->n_chan = 5;
    s->maxdata = 1;
    s->range_table = &range_digital;
    s->insn_bits = parport_insn_b;

    s = &dev->subdevices[2];
    s->type = COMEDI_SUBD_DO;
    s->subdev_flags = SDF_WRITABLE;
    s->n_chan = 4;
    s->maxdata = 1;
    s->range_table = &range_digital;
    s->insn_bits = parport_insn_c;

    s = &dev->subdevices[3];
    if (irq) {
        dev->read_subdev = s;
        s->type = COMEDI_SUBD_DI;
        s->subdev_flags = SDF_READABLE | SDF_CMD_READ;
        s->n_chan = 1;
        s->maxdata = 1;
        s->range_table = &range_digital;
        s->insn_bits = parport_intr_insn;
        s->do_cmdtest = parport_intr_cmdtest;
        s->do_cmd = parport_intr_cmd;
        s->cancel = parport_intr_cancel;
    } else {
        s->type = COMEDI_SUBD_UNUSED;
    }

    devpriv->a_data = 0;
    outb(devpriv->a_data, dev->iobase + PARPORT_A);
    devpriv->c_data = 0;
    outb(devpriv->c_data, dev->iobase + PARPORT_C);

    dev_info(dev->class_dev, "%s: iobase=0x%04lx, irq %sabled",
        dev->board_name, dev->iobase, dev->irq ? "en" : "dis");

    return 0;
}

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

static struct comedi_driver parport_driver = {
    .driver_name    = "comedi_parport",
    .module     = THIS_MODULE,
    .attach     = parport_attach,
    .detach     = parport_detach,
};
module_comedi_driver(parport_driver);

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