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/*
* comedi/drivers/8255.c
* Driver for 8255
*
* COMEDI - Linux Control and Measurement Device Interface
* Copyright (C) 1998 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.
*/
/*
* Driver: 8255
* Description: generic 8255 support
* Devices: [standard] 8255 (8255)
* Author: ds
* Status: works
* Updated: Fri, 7 Jun 2002 12:56:45 -0700
*
* The classic in digital I/O. The 8255 appears in Comedi as a single
* digital I/O subdevice with 24 channels. The channel 0 corresponds
* to the 8255's port A, bit 0; channel 23 corresponds to port C, bit
* 7. Direction configuration is done in blocks, with channels 0-7,
* 8-15, 16-19, and 20-23 making up the 4 blocks. The only 8255 mode
* supported is mode 0.
*
* You should enable compilation this driver if you plan to use a board
* that has an 8255 chip. For multifunction boards, the main driver will
* configure the 8255 subdevice automatically.
*
* This driver also works independently with ISA and PCI cards that
* directly map the 8255 registers to I/O ports, including cards with
* multiple 8255 chips. To configure the driver for such a card, the
* option list should be a list of the I/O port bases for each of the
* 8255 chips. For example,
*
* comedi_config /dev/comedi0 8255 0x200,0x204,0x208,0x20c
*
* Note that most PCI 8255 boards do NOT work with this driver, and
* need a separate driver as a wrapper. For those that do work, the
* I/O port base address can be found in the output of 'lspci -v'.
*/
#include <linux/module.h>
#include "../comedidev.h"
#include "8255.h"
static int dev_8255_attach(struct comedi_device *dev,
struct comedi_devconfig *it)
{
struct comedi_subdevice *s;
unsigned long iobase;
int ret;
int i;
for (i = 0; i < COMEDI_NDEVCONFOPTS; i++) {
iobase = it->options[i];
if (!iobase)
break;
}
if (i == 0) {
dev_warn(dev->class_dev, "no devices specified\n");
return -EINVAL;
}
ret = comedi_alloc_subdevices(dev, i);
if (ret)
return ret;
for (i = 0; i < dev->n_subdevices; i++) {
s = &dev->subdevices[i];
iobase = it->options[i];
/*
* __comedi_request_region() does not set dev->iobase.
*
* For 8255 devices that are manually attached using
* comedi_config, the 'iobase' is the actual I/O port
* base address of the chip.
*/
ret = __comedi_request_region(dev, iobase, I8255_SIZE);
if (ret) {
s->type = COMEDI_SUBD_UNUSED;
} else {
ret = subdev_8255_init(dev, s, NULL, iobase);
if (ret) {
/*
* Release the I/O port region here, as the
* "detach" handler cannot find it.
*/
release_region(iobase, I8255_SIZE);
s->type = COMEDI_SUBD_UNUSED;
return ret;
}
}
}
return 0;
}
static void dev_8255_detach(struct comedi_device *dev)
{
struct comedi_subdevice *s;
int i;
for (i = 0; i < dev->n_subdevices; i++) {
s = &dev->subdevices[i];
if (s->type != COMEDI_SUBD_UNUSED) {
unsigned long regbase = subdev_8255_regbase(s);
release_region(regbase, I8255_SIZE);
}
}
}
static struct comedi_driver dev_8255_driver = {
.driver_name = "8255",
.module = THIS_MODULE,
.attach = dev_8255_attach,
.detach = dev_8255_detach,
};
module_comedi_driver(dev_8255_driver);
MODULE_AUTHOR("Comedi http://www.comedi.org");
MODULE_DESCRIPTION("Comedi driver for standalone 8255 devices");
MODULE_LICENSE("GPL");
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