// SPDX-License-Identifier: GPL-2.0+
/*
 * das6402.c
 * Comedi driver for DAS6402 compatible boards
 * Copyright(c) 2014 H Hartley Sweeten <hsweeten@visionengravers.com>
 *
 * Rewrite of an experimental driver by:
 * Copyright (C) 1999 Oystein Svendsen <svendsen@pvv.org>
 */

/*
 * Driver: das6402
 * Description: Keithley Metrabyte DAS6402 (& compatibles)
 * Devices: [Keithley Metrabyte] DAS6402-12 (das6402-12),
 *   DAS6402-16 (das6402-16)
 * Author: H Hartley Sweeten <hsweeten@visionengravers.com>
 * Updated: Fri, 14 Mar 2014 10:18:43 -0700
 * Status: unknown
 *
 * Configuration Options:
 *   [0] - I/O base address
 *   [1] - IRQ (optional, needed for async command support)
 */

#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/comedi/comedidev.h>
#include <linux/comedi/comedi_8254.h>

/*
 * Register I/O map
 */
#define DAS6402_AI_DATA_REG             0x00
#define DAS6402_AI_MUX_REG              0x02
#define DAS6402_AI_MUX_LO(x)            (((x) & 0x3f) << 0)
#define DAS6402_AI_MUX_HI(x)            (((x) & 0x3f) << 8)
#define DAS6402_DI_DO_REG               0x03
#define DAS6402_AO_DATA_REG(x)          (0x04 + ((x) * 2))
#define DAS6402_AO_LSB_REG(x)           (0x04 + ((x) * 2))
#define DAS6402_AO_MSB_REG(x)           (0x05 + ((x) * 2))
#define DAS6402_STATUS_REG              0x08
#define DAS6402_STATUS_FFNE             BIT(0)
#define DAS6402_STATUS_FHALF            BIT(1)
#define DAS6402_STATUS_FFULL            BIT(2)
#define DAS6402_STATUS_XINT             BIT(3)
#define DAS6402_STATUS_INT              BIT(4)
#define DAS6402_STATUS_XTRIG            BIT(5)
#define DAS6402_STATUS_INDGT            BIT(6)
#define DAS6402_STATUS_10MHZ            BIT(7)
#define DAS6402_STATUS_W_CLRINT         BIT(0)
#define DAS6402_STATUS_W_CLRXTR         BIT(1)
#define DAS6402_STATUS_W_CLRXIN         BIT(2)
#define DAS6402_STATUS_W_EXTEND         BIT(4)
#define DAS6402_STATUS_W_ARMED          BIT(5)
#define DAS6402_STATUS_W_POSTMODE       BIT(6)
#define DAS6402_STATUS_W_10MHZ          BIT(7)
#define DAS6402_CTRL_REG                0x09
#define DAS6402_CTRL_TRIG(x)            ((x) << 0)
#define DAS6402_CTRL_SOFT_TRIG          DAS6402_CTRL_TRIG(0)
#define DAS6402_CTRL_EXT_FALL_TRIG      DAS6402_CTRL_TRIG(1)
#define DAS6402_CTRL_EXT_RISE_TRIG      DAS6402_CTRL_TRIG(2)
#define DAS6402_CTRL_PACER_TRIG         DAS6402_CTRL_TRIG(3)
#define DAS6402_CTRL_BURSTEN            BIT(2)
#define DAS6402_CTRL_XINTE              BIT(3)
#define DAS6402_CTRL_IRQ(x)             ((x) << 4)
#define DAS6402_CTRL_INTE               BIT(7)
#define DAS6402_TRIG_REG                0x0a
#define DAS6402_TRIG_TGEN               BIT(0)
#define DAS6402_TRIG_TGSEL              BIT(1)
#define DAS6402_TRIG_TGPOL              BIT(2)
#define DAS6402_TRIG_PRETRIG            BIT(3)
#define DAS6402_AO_RANGE(_chan, _range) ((_range) << ((_chan) ? 6 : 4))
#define DAS6402_AO_RANGE_MASK(_chan)    (3 << ((_chan) ? 6 : 4))
#define DAS6402_MODE_REG                0x0b
#define DAS6402_MODE_RANGE(x)           ((x) << 2)
#define DAS6402_MODE_POLLED             DAS6402_MODE_RANGE(0)
#define DAS6402_MODE_FIFONEPTY          DAS6402_MODE_RANGE(1)
#define DAS6402_MODE_FIFOHFULL          DAS6402_MODE_RANGE(2)
#define DAS6402_MODE_EOB                DAS6402_MODE_RANGE(3)
#define DAS6402_MODE_ENHANCED           BIT(4)
#define DAS6402_MODE_SE                 BIT(5)
#define DAS6402_MODE_UNI                BIT(6)
#define DAS6402_MODE_DMA(x)             ((x) << 7)
#define DAS6402_MODE_DMA1               DAS6402_MODE_DMA(0)
#define DAS6402_MODE_DMA3               DAS6402_MODE_DMA(1)
#define DAS6402_TIMER_BASE              0x0c

static const struct comedi_lrange das6402_ai_ranges = {
        8, {
                BIP_RANGE(10),
                BIP_RANGE(5),
                BIP_RANGE(2.5),
                BIP_RANGE(1.25),
                UNI_RANGE(10),
                UNI_RANGE(5),
                UNI_RANGE(2.5),
                UNI_RANGE(1.25)
        }
};

/*
 * Analog output ranges are programmable on the DAS6402/12.
 * For the DAS6402/16 the range bits have no function, the
 * DAC ranges are selected by switches on the board.
 */
static const struct comedi_lrange das6402_ao_ranges = {
        4, {
                BIP_RANGE(5),
                BIP_RANGE(10),
                UNI_RANGE(5),
                UNI_RANGE(10)
        }
};

struct das6402_boardinfo {
        const char *name;
        unsigned int maxdata;
};

static struct das6402_boardinfo das6402_boards[] = {
        {
                .name           = "das6402-12",
                .maxdata        = 0x0fff,
        }, {
                .name           = "das6402-16",
                .maxdata        = 0xffff,
        },
};

struct das6402_private {
        unsigned int irq;
        unsigned int ao_range;
};

static void das6402_set_mode(struct comedi_device *dev,
                             unsigned int mode)
{
        outb(DAS6402_MODE_ENHANCED | mode, dev->iobase + DAS6402_MODE_REG);
}

static void das6402_set_extended(struct comedi_device *dev,
                                 unsigned int val)
{
        outb(DAS6402_STATUS_W_EXTEND, dev->iobase + DAS6402_STATUS_REG);
        outb(DAS6402_STATUS_W_EXTEND | val, dev->iobase + DAS6402_STATUS_REG);
        outb(val, dev->iobase + DAS6402_STATUS_REG);
}

static void das6402_clear_all_interrupts(struct comedi_device *dev)
{
        outb(DAS6402_STATUS_W_CLRINT |
             DAS6402_STATUS_W_CLRXTR |
             DAS6402_STATUS_W_CLRXIN, dev->iobase + DAS6402_STATUS_REG);
}

static void das6402_ai_clear_eoc(struct comedi_device *dev)
{
        outb(DAS6402_STATUS_W_CLRINT, dev->iobase + DAS6402_STATUS_REG);
}

static unsigned int das6402_ai_read_sample(struct comedi_device *dev,
                                           struct comedi_subdevice *s)
{
        unsigned int val;

        val = inw(dev->iobase + DAS6402_AI_DATA_REG);
        if (s->maxdata == 0x0fff)
                val >>= 4;
        return val;
}

static irqreturn_t das6402_interrupt(int irq, void *d)
{
        struct comedi_device *dev = d;
        struct comedi_subdevice *s = dev->read_subdev;
        struct comedi_async *async = s->async;
        struct comedi_cmd *cmd = &async->cmd;
        unsigned int status;

        status = inb(dev->iobase + DAS6402_STATUS_REG);
        if ((status & DAS6402_STATUS_INT) == 0)
                return IRQ_NONE;

        if (status & DAS6402_STATUS_FFULL) {
                async->events |= COMEDI_CB_OVERFLOW;
        } else if (status & DAS6402_STATUS_FFNE) {
                unsigned short val;

                val = das6402_ai_read_sample(dev, s);
                comedi_buf_write_samples(s, &val, 1);

                if (cmd->stop_src == TRIG_COUNT &&
                    async->scans_done >= cmd->stop_arg)
                        async->events |= COMEDI_CB_EOA;
        }

        das6402_clear_all_interrupts(dev);

        comedi_handle_events(dev, s);

        return IRQ_HANDLED;
}

static void das6402_ai_set_mode(struct comedi_device *dev,
                                struct comedi_subdevice *s,
                                unsigned int chanspec,
                                unsigned int mode)
{
        unsigned int range = CR_RANGE(chanspec);
        unsigned int aref = CR_AREF(chanspec);

        mode |= DAS6402_MODE_RANGE(range);
        if (aref == AREF_GROUND)
                mode |= DAS6402_MODE_SE;
        if (comedi_range_is_unipolar(s, range))
                mode |= DAS6402_MODE_UNI;

        das6402_set_mode(dev, mode);
}

static int das6402_ai_cmd(struct comedi_device *dev,
                          struct comedi_subdevice *s)
{
        struct das6402_private *devpriv = dev->private;
        struct comedi_cmd *cmd = &s->async->cmd;
        unsigned int chan_lo = CR_CHAN(cmd->chanlist[0]);
        unsigned int chan_hi = CR_CHAN(cmd->chanlist[cmd->chanlist_len - 1]);

        das6402_ai_set_mode(dev, s, cmd->chanlist[0], DAS6402_MODE_FIFONEPTY);

        /* load the mux for chanlist conversion */
        outw(DAS6402_AI_MUX_HI(chan_hi) | DAS6402_AI_MUX_LO(chan_lo),
             dev->iobase + DAS6402_AI_MUX_REG);

        comedi_8254_update_divisors(dev->pacer);
        comedi_8254_pacer_enable(dev->pacer, 1, 2, true);

        /* enable interrupt and pacer trigger */
        outb(DAS6402_CTRL_INTE |
             DAS6402_CTRL_IRQ(devpriv->irq) |
             DAS6402_CTRL_PACER_TRIG, dev->iobase + DAS6402_CTRL_REG);

        return 0;
}

static int das6402_ai_check_chanlist(struct comedi_device *dev,
                                     struct comedi_subdevice *s,
                                     struct comedi_cmd *cmd)
{
        unsigned int chan0 = CR_CHAN(cmd->chanlist[0]);
        unsigned int range0 = CR_RANGE(cmd->chanlist[0]);
        unsigned int aref0 = CR_AREF(cmd->chanlist[0]);
        int i;

        for (i = 1; i < cmd->chanlist_len; i++) {
                unsigned int chan = CR_CHAN(cmd->chanlist[i]);
                unsigned int range = CR_RANGE(cmd->chanlist[i]);
                unsigned int aref = CR_AREF(cmd->chanlist[i]);

                if (chan != chan0 + i) {
                        dev_dbg(dev->class_dev,
                                "chanlist must be consecutive\n");
                        return -EINVAL;
                }

                if (range != range0) {
                        dev_dbg(dev->class_dev,
                                "chanlist must have the same range\n");
                        return -EINVAL;
                }

                if (aref != aref0) {
                        dev_dbg(dev->class_dev,
                                "chanlist must have the same reference\n");
                        return -EINVAL;
                }

                if (aref0 == AREF_DIFF && chan > (s->n_chan / 2)) {
                        dev_dbg(dev->class_dev,
                                "chanlist differential channel too large\n");
                        return -EINVAL;
                }
        }
        return 0;
}

static int das6402_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_FOLLOW);
        err |= comedi_check_trigger_src(&cmd->convert_src, TRIG_TIMER);
        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_is(&cmd->scan_begin_arg, 0);
        err |= comedi_check_trigger_arg_min(&cmd->convert_arg, 10000);
        err |= comedi_check_trigger_arg_min(&cmd->chanlist_len, 1);
        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, 1);
        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->convert_arg;
        comedi_8254_cascade_ns_to_timer(dev->pacer, &arg, cmd->flags);
        err |= comedi_check_trigger_arg_is(&cmd->convert_arg, arg);

        if (err)
                return 4;

        /* Step 5: check channel list if it exists */
        if (cmd->chanlist && cmd->chanlist_len > 0)
                err |= das6402_ai_check_chanlist(dev, s, cmd);

        if (err)
                return 5;

        return 0;
}

static int das6402_ai_cancel(struct comedi_device *dev,
                             struct comedi_subdevice *s)
{
        outb(DAS6402_CTRL_SOFT_TRIG, dev->iobase + DAS6402_CTRL_REG);

        return 0;
}

static void das6402_ai_soft_trig(struct comedi_device *dev)
{
        outw(0, dev->iobase + DAS6402_AI_DATA_REG);
}

static int das6402_ai_eoc(struct comedi_device *dev,
                          struct comedi_subdevice *s,
                          struct comedi_insn *insn,
                          unsigned long context)
{
        unsigned int status;

        status = inb(dev->iobase + DAS6402_STATUS_REG);
        if (status & DAS6402_STATUS_FFNE)
                return 0;
        return -EBUSY;
}

static int das6402_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 aref = CR_AREF(insn->chanspec);
        int ret;
        int i;

        if (aref == AREF_DIFF && chan > (s->n_chan / 2))
                return -EINVAL;

        /* enable software conversion trigger */
        outb(DAS6402_CTRL_SOFT_TRIG, dev->iobase + DAS6402_CTRL_REG);

        das6402_ai_set_mode(dev, s, insn->chanspec, DAS6402_MODE_POLLED);

        /* load the mux for single channel conversion */
        outw(DAS6402_AI_MUX_HI(chan) | DAS6402_AI_MUX_LO(chan),
             dev->iobase + DAS6402_AI_MUX_REG);

        for (i = 0; i < insn->n; i++) {
                das6402_ai_clear_eoc(dev);
                das6402_ai_soft_trig(dev);

                ret = comedi_timeout(dev, s, insn, das6402_ai_eoc, 0);
                if (ret)
                        break;

                data[i] = das6402_ai_read_sample(dev, s);
        }

        das6402_ai_clear_eoc(dev);

        return insn->n;
}

static int das6402_ao_insn_write(struct comedi_device *dev,
                                 struct comedi_subdevice *s,
                                 struct comedi_insn *insn,
                                 unsigned int *data)
{
        struct das6402_private *devpriv = dev->private;
        unsigned int chan = CR_CHAN(insn->chanspec);
        unsigned int range = CR_RANGE(insn->chanspec);
        unsigned int val;
        int i;

        /* set the range for this channel */
        val = devpriv->ao_range;
        val &= ~DAS6402_AO_RANGE_MASK(chan);
        val |= DAS6402_AO_RANGE(chan, range);
        if (val != devpriv->ao_range) {
                devpriv->ao_range = val;
                outb(val, dev->iobase + DAS6402_TRIG_REG);
        }

        /*
         * The DAS6402/16 has a jumper to select either individual
         * update (UPDATE) or simultaneous updating (XFER) of both
         * DAC's. In UPDATE mode, when the MSB is written, that DAC
         * is updated. In XFER mode, after both DAC's are loaded,
         * a read cycle of any DAC register will update both DAC's
         * simultaneously.
         *
         * If you have XFER mode enabled a (*insn_read) will need
         * to be performed in order to update the DAC's with the
         * last value written.
         */
        for (i = 0; i < insn->n; i++) {
                val = data[i];

                s->readback[chan] = val;

                if (s->maxdata == 0x0fff) {
                        /*
                         * DAS6402/12 has the two 8-bit DAC registers, left
                         * justified (the 4 LSB bits are don't care). Data
                         * can be written as one word.
                         */
                        val <<= 4;
                        outw(val, dev->iobase + DAS6402_AO_DATA_REG(chan));
                } else {
                        /*
                         * DAS6402/16 uses both 8-bit DAC registers and needs
                         * to be written LSB then MSB.
                         */
                        outb(val & 0xff,
                             dev->iobase + DAS6402_AO_LSB_REG(chan));
                        outb((val >> 8) & 0xff,
                             dev->iobase + DAS6402_AO_LSB_REG(chan));
                }
        }

        return insn->n;
}

static int das6402_ao_insn_read(struct comedi_device *dev,
                                struct comedi_subdevice *s,
                                struct comedi_insn *insn,
                                unsigned int *data)
{
        unsigned int chan = CR_CHAN(insn->chanspec);

        /*
         * If XFER mode is enabled, reading any DAC register
         * will update both DAC's simultaneously.
         */
        inw(dev->iobase + DAS6402_AO_LSB_REG(chan));

        return comedi_readback_insn_read(dev, s, insn, data);
}

static int das6402_di_insn_bits(struct comedi_device *dev,
                                struct comedi_subdevice *s,
                                struct comedi_insn *insn,
                                unsigned int *data)
{
        data[1] = inb(dev->iobase + DAS6402_DI_DO_REG);

        return insn->n;
}

static int das6402_do_insn_bits(struct comedi_device *dev,
                                struct comedi_subdevice *s,
                                struct comedi_insn *insn,
                                unsigned int *data)
{
        if (comedi_dio_update_state(s, data))
                outb(s->state, dev->iobase + DAS6402_DI_DO_REG);

        data[1] = s->state;

        return insn->n;
}

static void das6402_reset(struct comedi_device *dev)
{
        struct das6402_private *devpriv = dev->private;

        /* enable "Enhanced" mode */
        outb(DAS6402_MODE_ENHANCED, dev->iobase + DAS6402_MODE_REG);

        /* enable 10MHz pacer clock */
        das6402_set_extended(dev, DAS6402_STATUS_W_10MHZ);

        /* enable software conversion trigger */
        outb(DAS6402_CTRL_SOFT_TRIG, dev->iobase + DAS6402_CTRL_REG);

        /* default ADC to single-ended unipolar 10V inputs */
        das6402_set_mode(dev, DAS6402_MODE_RANGE(0) |
                              DAS6402_MODE_POLLED |
                              DAS6402_MODE_SE |
                              DAS6402_MODE_UNI);

        /* default mux for single channel conversion (channel 0) */
        outw(DAS6402_AI_MUX_HI(0) | DAS6402_AI_MUX_LO(0),
             dev->iobase + DAS6402_AI_MUX_REG);

        /* set both DAC's for unipolar 5V output range */
        devpriv->ao_range = DAS6402_AO_RANGE(0, 2) | DAS6402_AO_RANGE(1, 2);
        outb(devpriv->ao_range, dev->iobase + DAS6402_TRIG_REG);

        /* set both DAC's to 0V */
        outw(0, dev->iobase + DAS6402_AO_DATA_REG(0));
        outw(0, dev->iobase + DAS6402_AO_DATA_REG(0));
        inw(dev->iobase + DAS6402_AO_LSB_REG(0));

        /* set all digital outputs low */
        outb(0, dev->iobase + DAS6402_DI_DO_REG);

        das6402_clear_all_interrupts(dev);
}

static int das6402_attach(struct comedi_device *dev,
                          struct comedi_devconfig *it)
{
        const struct das6402_boardinfo *board = dev->board_ptr;
        struct das6402_private *devpriv;
        struct comedi_subdevice *s;
        int ret;

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

        ret = comedi_request_region(dev, it->options[0], 0x10);
        if (ret)
                return ret;

        das6402_reset(dev);

        /* IRQs 2,3,5,6,7, 10,11,15 are valid for "enhanced" mode */
        if (it->options[1] > 0 && it->options[1] < 16 &&
            (1 << it->options[1]) & 0x8cec) {
                ret = request_irq(it->options[1], das6402_interrupt, 0,
                                  dev->board_name, dev);
                if (ret == 0) {
                        dev->irq = it->options[1];

                        switch (dev->irq) {
                        case 10:
                                devpriv->irq = 4;
                                break;
                        case 11:
                                devpriv->irq = 1;
                                break;
                        case 15:
                                devpriv->irq = 6;
                                break;
                        default:
                                devpriv->irq = dev->irq;
                                break;
                        }
                }
        }

        dev->pacer = comedi_8254_io_alloc(dev->iobase + DAS6402_TIMER_BASE,
                                          I8254_OSC_BASE_10MHZ, I8254_IO8, 0);
        if (IS_ERR(dev->pacer))
                return PTR_ERR(dev->pacer);

        ret = comedi_alloc_subdevices(dev, 4);
        if (ret)
                return ret;

        /* Analog Input subdevice */
        s = &dev->subdevices[0];
        s->type         = COMEDI_SUBD_AI;
        s->subdev_flags = SDF_READABLE | SDF_GROUND | SDF_DIFF;
        s->n_chan       = 64;
        s->maxdata      = board->maxdata;
        s->range_table  = &das6402_ai_ranges;
        s->insn_read    = das6402_ai_insn_read;
        if (dev->irq) {
                dev->read_subdev = s;
                s->subdev_flags |= SDF_CMD_READ;
                s->len_chanlist = s->n_chan;
                s->do_cmdtest   = das6402_ai_cmdtest;
                s->do_cmd       = das6402_ai_cmd;
                s->cancel       = das6402_ai_cancel;
        }

        /* Analog Output subdevice */
        s = &dev->subdevices[1];
        s->type         = COMEDI_SUBD_AO;
        s->subdev_flags = SDF_WRITABLE;
        s->n_chan       = 2;
        s->maxdata      = board->maxdata;
        s->range_table  = &das6402_ao_ranges;
        s->insn_write   = das6402_ao_insn_write;
        s->insn_read    = das6402_ao_insn_read;

        ret = comedi_alloc_subdev_readback(s);
        if (ret)
                return ret;

        /* Digital Input subdevice */
        s = &dev->subdevices[2];
        s->type         = COMEDI_SUBD_DI;
        s->subdev_flags = SDF_READABLE;
        s->n_chan       = 8;
        s->maxdata      = 1;
        s->range_table  = &range_digital;
        s->insn_bits    = das6402_di_insn_bits;

        /* Digital Input subdevice */
        s = &dev->subdevices[3];
        s->type         = COMEDI_SUBD_DO;
        s->subdev_flags = SDF_WRITABLE;
        s->n_chan       = 8;
        s->maxdata      = 1;
        s->range_table  = &range_digital;
        s->insn_bits    = das6402_do_insn_bits;

        return 0;
}

static struct comedi_driver das6402_driver = {
        .driver_name    = "das6402",
        .module         = THIS_MODULE,
        .attach         = das6402_attach,
        .detach         = comedi_legacy_detach,
        .board_name     = &das6402_boards[0].name,
        .num_names      = ARRAY_SIZE(das6402_boards),
        .offset         = sizeof(struct das6402_boardinfo),
};
module_comedi_driver(das6402_driver)

MODULE_AUTHOR("H Hartley Sweeten <hsweeten@visionengravers.com>");
MODULE_DESCRIPTION("Comedi driver for DAS6402 compatible boards");
MODULE_LICENSE("GPL");