// SPDX-License-Identifier: GPL-2.0+
/*
 * dac02.c
 * Comedi driver for DAC02 compatible boards
 * Copyright (C) 2014 H Hartley Sweeten <hsweeten@visionengravers.com>
 *
 * Based on the poc driver
 * Copyright (C) 2000 Frank Mori Hess <fmhess@users.sourceforge.net>
 * Copyright (C) 2001 David A. Schleef <ds@schleef.org>
 *
 * COMEDI - Linux Control and Measurement Device Interface
 * Copyright (C) 1998 David A. Schleef <ds@schleef.org>
 */

/*
 * Driver: dac02
 * Description: Comedi driver for DAC02 compatible boards
 * Devices: [Keithley Metrabyte] DAC-02 (dac02)
 * Author: H Hartley Sweeten <hsweeten@visionengravers.com>
 * Updated: Tue, 11 Mar 2014 11:27:19 -0700
 * Status: unknown
 *
 * Configuration options:
 *      [0] - I/O port base
 */

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

/*
 * The output range is selected by jumpering pins on the I/O connector.
 *
 *          Range      Chan #   Jumper pins        Output
 *      -------------  ------  -------------  -----------------
 *         0 to 5V       0        21 to 22      24
 *                       1        15 to 16      18
 *         0 to 10V      0        20 to 22      24
 *                       1        14 to 16      18
 *          +/-5V        0        21 to 22      23
 *                       1        15 to 16      17
 *          +/-10V       0        20 to 22      23
 *                       1        14 to 16      17
 *        4 to 20mA      0        21 to 22      25
 *                       1        15 to 16      19
 *      AC reference     0      In on pin 22    24 (2-quadrant)
 *                              In on pin 22    23 (4-quadrant)
 *                       1      In on pin 16    18 (2-quadrant)
 *                              In on pin 16    17 (4-quadrant)
 */
static const struct comedi_lrange das02_ao_ranges = {
        6, {
                UNI_RANGE(5),
                UNI_RANGE(10),
                BIP_RANGE(5),
                BIP_RANGE(10),
                RANGE_mA(4, 20),
                RANGE_ext(0, 1)
        }
};

/*
 * Register I/O map
 */
#define DAC02_AO_LSB(x)         (0x00 + ((x) * 2))
#define DAC02_AO_MSB(x)         (0x01 + ((x) * 2))

static int dac02_ao_insn_write(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 i;

        for (i = 0; i < insn->n; i++) {
                val = data[i];

                s->readback[chan] = val;

                /*
                 * Unipolar outputs are true binary encoding.
                 * Bipolar outputs are complementary offset binary
                 * (that is, 0 = +full scale, maxdata = -full scale).
                 */
                if (comedi_range_is_bipolar(s, range))
                        val = s->maxdata - val;

                /*
                 * DACs are double-buffered.
                 * Write LSB then MSB to latch output.
                 */
                outb((val << 4) & 0xf0, dev->iobase + DAC02_AO_LSB(chan));
                outb((val >> 4) & 0xff, dev->iobase + DAC02_AO_MSB(chan));
        }

        return insn->n;
}

static int dac02_attach(struct comedi_device *dev, struct comedi_devconfig *it)
{
        struct comedi_subdevice *s;
        int ret;

        ret = comedi_check_request_region(dev, it->options[0], 0x08,
                                          0x200, 0x3ff, 8);
        if (ret)
                return ret;

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

        /* Analog Output subdevice */
        s = &dev->subdevices[0];
        s->type         = COMEDI_SUBD_AO;
        s->subdev_flags = SDF_WRITABLE;
        s->n_chan       = 2;
        s->maxdata      = 0x0fff;
        s->range_table  = &das02_ao_ranges;
        s->insn_write   = dac02_ao_insn_write;

        return comedi_alloc_subdev_readback(s);
}

static struct comedi_driver dac02_driver = {
        .driver_name    = "dac02",
        .module         = THIS_MODULE,
        .attach         = dac02_attach,
        .detach         = comedi_legacy_detach,
};
module_comedi_driver(dac02_driver);

MODULE_AUTHOR("H Hartley Sweeten <hsweeten@visionengravers.com>");
MODULE_DESCRIPTION("Comedi driver for DAC02 compatible boards");
MODULE_LICENSE("GPL");