/*
 * comedi/drivers/dt2814.c
 * Hardware driver for Data Translation DT2814
 *
 * 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: dt2814
 * Description: Data Translation DT2814
 * Author: ds
 * Status: complete
 * Devices: [Data Translation] DT2814 (dt2814)
 *
 * Configuration options:
 * [0] - I/O port base address
 * [1] - IRQ
 *
 * This card has 16 analog inputs multiplexed onto a 12 bit ADC.  There
 * is a minimally useful onboard clock.  The base frequency for the
 * clock is selected by jumpers, and the clock divider can be selected
 * via programmed I/O.  Unfortunately, the clock divider can only be
 * a power of 10, from 1 to 10^7, of which only 3 or 4 are useful.  In
 * addition, the clock does not seem to be very accurate.
 */

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

#include <linux/delay.h>

#define DT2814_CSR 0
#define DT2814_DATA 1

/*
 * flags
 */

#define DT2814_FINISH 0x80
#define DT2814_ERR 0x40
#define DT2814_BUSY 0x20
#define DT2814_ENB 0x10
#define DT2814_CHANMASK 0x0f

struct dt2814_private {
        int ntrig;
        int curadchan;
};

#define DT2814_TIMEOUT 10
#define DT2814_MAX_SPEED 100000 /* Arbitrary 10 khz limit */

static int dt2814_ai_eoc(struct comedi_device *dev,
                         struct comedi_subdevice *s,
                         struct comedi_insn *insn,
                         unsigned long context)
{
        unsigned int status;

        status = inb(dev->iobase + DT2814_CSR);
        if (status & DT2814_FINISH)
                return 0;
        return -EBUSY;
}

static int dt2814_ai_insn_read(struct comedi_device *dev,
                               struct comedi_subdevice *s,
                               struct comedi_insn *insn, unsigned int *data)
{
        int n, hi, lo;
        int chan;
        int ret;

        for (n = 0; n < insn->n; n++) {
                chan = CR_CHAN(insn->chanspec);

                outb(chan, dev->iobase + DT2814_CSR);

                ret = comedi_timeout(dev, s, insn, dt2814_ai_eoc, 0);
                if (ret)
                        return ret;

                hi = inb(dev->iobase + DT2814_DATA);
                lo = inb(dev->iobase + DT2814_DATA);

                data[n] = (hi << 4) | (lo >> 4);
        }

        return n;
}

static int dt2814_ns_to_timer(unsigned int *ns, unsigned int flags)
{
        int i;
        unsigned int f;

        /* XXX ignores flags */

        f = 10000;              /* ns */
        for (i = 0; i < 8; i++) {
                if ((2 * (*ns)) < (f * 11))
                        break;
                f *= 10;
        }

        *ns = f;

        return i;
}

static int dt2814_ai_cmdtest(struct comedi_device *dev,
                             struct comedi_subdevice *s, struct comedi_cmd *cmd)
{
        int err = 0;
        unsigned int arg;

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

        err |= comedi_check_trigger_src(&cmd->start_src, TRIG_NOW);
        err |= comedi_check_trigger_src(&cmd->scan_begin_src, TRIG_TIMER);
        err |= comedi_check_trigger_src(&cmd->convert_src, TRIG_NOW);
        err |= comedi_check_trigger_src(&cmd->scan_end_src, TRIG_COUNT);
        err |= comedi_check_trigger_src(&cmd->stop_src, TRIG_COUNT | TRIG_NONE);

        if (err)
                return 1;

        /* Step 2a : make sure trigger sources are unique */

        err |= comedi_check_trigger_is_unique(cmd->stop_src);

        /* Step 2b : and mutually compatible */

        if (err)
                return 2;

        /* Step 3: check if arguments are trivially valid */

        err |= comedi_check_trigger_arg_is(&cmd->start_arg, 0);

        err |= comedi_check_trigger_arg_max(&cmd->scan_begin_arg, 1000000000);
        err |= comedi_check_trigger_arg_min(&cmd->scan_begin_arg,
                                            DT2814_MAX_SPEED);

        err |= comedi_check_trigger_arg_is(&cmd->scan_end_arg,
                                           cmd->chanlist_len);

        if (cmd->stop_src == TRIG_COUNT)
                err |= comedi_check_trigger_arg_min(&cmd->stop_arg, 2);
        else    /* TRIG_NONE */
                err |= comedi_check_trigger_arg_is(&cmd->stop_arg, 0);

        if (err)
                return 3;

        /* step 4: fix up any arguments */

        arg = cmd->scan_begin_arg;
        dt2814_ns_to_timer(&arg, cmd->flags);
        err |= comedi_check_trigger_arg_is(&cmd->scan_begin_arg, arg);

        if (err)
                return 4;

        return 0;
}

static int dt2814_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
{
        struct dt2814_private *devpriv = dev->private;
        struct comedi_cmd *cmd = &s->async->cmd;
        int chan;
        int trigvar;

        trigvar = dt2814_ns_to_timer(&cmd->scan_begin_arg, cmd->flags);

        chan = CR_CHAN(cmd->chanlist[0]);

        devpriv->ntrig = cmd->stop_arg;
        outb(chan | DT2814_ENB | (trigvar << 5), dev->iobase + DT2814_CSR);

        return 0;
}

static irqreturn_t dt2814_interrupt(int irq, void *d)
{
        int lo, hi;
        struct comedi_device *dev = d;
        struct dt2814_private *devpriv = dev->private;
        struct comedi_subdevice *s = dev->read_subdev;
        int data;

        if (!dev->attached) {
                dev_err(dev->class_dev, "spurious interrupt\n");
                return IRQ_HANDLED;
        }

        hi = inb(dev->iobase + DT2814_DATA);
        lo = inb(dev->iobase + DT2814_DATA);

        data = (hi << 4) | (lo >> 4);

        if (!(--devpriv->ntrig)) {
                int i;

                outb(0, dev->iobase + DT2814_CSR);
                /*
                 * note: turning off timed mode triggers another
                 * sample.
                 */

                for (i = 0; i < DT2814_TIMEOUT; i++) {
                        if (inb(dev->iobase + DT2814_CSR) & DT2814_FINISH)
                                break;
                }
                inb(dev->iobase + DT2814_DATA);
                inb(dev->iobase + DT2814_DATA);

                s->async->events |= COMEDI_CB_EOA;
        }
        comedi_handle_events(dev, s);
        return IRQ_HANDLED;
}

static int dt2814_attach(struct comedi_device *dev, struct comedi_devconfig *it)
{
        struct dt2814_private *devpriv;
        struct comedi_subdevice *s;
        int ret;
        int i;

        ret = comedi_request_region(dev, it->options[0], 0x2);
        if (ret)
                return ret;

        outb(0, dev->iobase + DT2814_CSR);
        usleep_range(100, 200);
        if (inb(dev->iobase + DT2814_CSR) & DT2814_ERR) {
                dev_err(dev->class_dev, "reset error (fatal)\n");
                return -EIO;
        }
        i = inb(dev->iobase + DT2814_DATA);
        i = inb(dev->iobase + DT2814_DATA);

        if (it->options[1]) {
                ret = request_irq(it->options[1], dt2814_interrupt, 0,
                                  dev->board_name, dev);
                if (ret == 0)
                        dev->irq = it->options[1];
        }

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

        devpriv = comedi_alloc_devpriv(dev, sizeof(*devpriv));
        if (!devpriv)
                return -ENOMEM;

        s = &dev->subdevices[0];
        s->type = COMEDI_SUBD_AI;
        s->subdev_flags = SDF_READABLE | SDF_GROUND;
        s->n_chan = 16;         /* XXX */
        s->insn_read = dt2814_ai_insn_read;
        s->maxdata = 0xfff;
        s->range_table = &range_unknown;        /* XXX */
        if (dev->irq) {
                dev->read_subdev = s;
                s->subdev_flags |= SDF_CMD_READ;
                s->len_chanlist = 1;
                s->do_cmd = dt2814_ai_cmd;
                s->do_cmdtest = dt2814_ai_cmdtest;
        }

        return 0;
}

static struct comedi_driver dt2814_driver = {
        .driver_name    = "dt2814",
        .module         = THIS_MODULE,
        .attach         = dt2814_attach,
        .detach         = comedi_legacy_detach,
};
module_comedi_driver(dt2814_driver);

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