// SPDX-License-Identifier: GPL-2.0+
/*
 * comedi/drivers/8255.c
 * Driver for 8255
 *
 * COMEDI - Linux Control and Measurement Device Interface
 * Copyright (C) 1998 David A. Schleef <ds@schleef.org>
 */

/*
 * 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 <linux/comedi/comedidev.h>
#include <linux/comedi/comedi_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)
                        return ret;
                ret = subdev_8255_io_init(dev, s, 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 https://www.comedi.org");
MODULE_DESCRIPTION("Comedi driver for standalone 8255 devices");
MODULE_LICENSE("GPL");