// SPDX-License-Identifier: GPL-2.0+
/*
 * 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>
 */

/*
 * Driver: pcmad
 * Description: Winsystems PCM-A/D12, PCM-A/D16
 * Devices: [Winsystems] PCM-A/D12 (pcmad12), PCM-A/D16 (pcmad16)
 * Author: ds
 * 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] - IRQ (unused)
 *   [2] - Analog input reference (must match jumpers)
 *         0 = single-ended (16 channels)
 *         1 = differential (8 channels)
 *   [3] - Analog input encoding (must match jumpers)
 *         0 = straight binary (0-5V input range)
 *         1 = two's complement (+-10V input range)
 */

#include <linux/module.h>
#include <linux/comedi/comedidev.h>

#define PCMAD_STATUS            0
#define PCMAD_LSB               1
#define PCMAD_MSB               2
#define PCMAD_CONVERT           1

struct pcmad_board_struct {
        const char *name;
        unsigned int ai_maxdata;
};

static const struct pcmad_board_struct pcmad_boards[] = {
        {
                .name           = "pcmad12",
                .ai_maxdata     = 0x0fff,
        }, {
                .name           = "pcmad16",
                .ai_maxdata     = 0xffff,
        },
};

static int pcmad_ai_eoc(struct comedi_device *dev,
                        struct comedi_subdevice *s,
                        struct comedi_insn *insn,
                        unsigned long context)
{
        unsigned int status;

        status = inb(dev->iobase + PCMAD_STATUS);
        if ((status & 0x3) == 0x3)
                return 0;
        return -EBUSY;
}

static int pcmad_ai_insn_read(struct comedi_device *dev,
                              struct comedi_subdevice *s,
                              struct comedi_insn *insn,
                              unsigned int *data)
{
        unsigned int chan = CR_CHAN(insn->chanspec);
        unsigned int range = CR_RANGE(insn->chanspec);
        unsigned int val;
        int ret;
        int i;

        for (i = 0; i < insn->n; i++) {
                outb(chan, dev->iobase + PCMAD_CONVERT);

                ret = comedi_timeout(dev, s, insn, pcmad_ai_eoc, 0);
                if (ret)
                        return ret;

                val = inb(dev->iobase + PCMAD_LSB) |
                      (inb(dev->iobase + PCMAD_MSB) << 8);

                /* data is shifted on the pcmad12, fix it */
                if (s->maxdata == 0x0fff)
                        val >>= 4;

                if (comedi_range_is_bipolar(s, range)) {
                        /* munge the two's complement value */
                        val ^= ((s->maxdata + 1) >> 1);
                }

                data[i] = val;
        }

        return insn->n;
}

static int pcmad_attach(struct comedi_device *dev, struct comedi_devconfig *it)
{
        const struct pcmad_board_struct *board = dev->board_ptr;
        struct comedi_subdevice *s;
        int ret;

        ret = comedi_request_region(dev, it->options[0], 0x04);
        if (ret)
                return ret;

        ret = comedi_alloc_subdevices(dev, 1);
        if (ret)
                return ret;

        s = &dev->subdevices[0];
        s->type         = COMEDI_SUBD_AI;
        if (it->options[1]) {
                /* 8 differential channels */
                s->subdev_flags = SDF_READABLE | AREF_DIFF;
                s->n_chan       = 8;
        } else {
                /* 16 single-ended channels */
                s->subdev_flags = SDF_READABLE | AREF_GROUND;
                s->n_chan       = 16;
        }
        s->len_chanlist = 1;
        s->maxdata      = board->ai_maxdata;
        s->range_table  = it->options[2] ? &range_bipolar10 : &range_unipolar5;
        s->insn_read    = pcmad_ai_insn_read;

        return 0;
}

static struct comedi_driver pcmad_driver = {
        .driver_name    = "pcmad",
        .module         = THIS_MODULE,
        .attach         = pcmad_attach,
        .detach         = comedi_legacy_detach,
        .board_name     = &pcmad_boards[0].name,
        .num_names      = ARRAY_SIZE(pcmad_boards),
        .offset         = sizeof(pcmad_boards[0]),
};
module_comedi_driver(pcmad_driver);

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