// SPDX-License-Identifier: GPL-2.0+
/*
 * Comedi driver for Data Translation DT2811
 *
 * COMEDI - Linux Control and Measurement Device Interface
 * Copyright (C) David A. Schleef <ds@schleef.org>
 */

/*
 * Driver: dt2811
 * Description: Data Translation DT2811
 * Author: ds
 * Devices: [Data Translation] DT2811-PGL (dt2811-pgl), DT2811-PGH (dt2811-pgh)
 * Status: works
 *
 * Configuration options:
 *   [0] - I/O port base address
 *   [1] - IRQ (optional, needed for async command support)
 *   [2] - A/D reference (# of analog inputs)
 *         0 = single-ended (16 channels)
 *         1 = differential (8 channels)
 *         2 = pseudo-differential (16 channels)
 *   [3] - A/D range (deprecated, see below)
 *   [4] - D/A 0 range (deprecated, see below)
 *   [5] - D/A 1 range (deprecated, see below)
 *
 * Notes:
 *   - A/D ranges are not programmable but the gain is. The AI subdevice has
 *     a range_table containing all the possible analog input range/gain
 *     options for the dt2811-pgh or dt2811-pgl. Use the range that matches
 *     your board configuration and the desired gain to correctly convert
 *     between data values and physical units and to set the correct output
 *     gain.
 *   - D/A ranges are not programmable. The AO subdevice has a range_table
 *     containing all the possible analog output ranges. Use the range
 *     that matches your board configuration to convert between data
 *     values and physical units.
 */

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

/*
 * Register I/O map
 */
#define DT2811_ADCSR_REG                0x00    /* r/w  A/D Control/Status */
#define DT2811_ADCSR_ADDONE             BIT(7)  /* r      1=A/D conv done */
#define DT2811_ADCSR_ADERROR            BIT(6)  /* r      1=A/D error */
#define DT2811_ADCSR_ADBUSY             BIT(5)  /* r      1=A/D busy */
#define DT2811_ADCSR_CLRERROR           BIT(4)
#define DT2811_ADCSR_DMAENB             BIT(3)  /* r/w    1=dma ena */
#define DT2811_ADCSR_INTENB             BIT(2)  /* r/w    1=interrupts ena */
#define DT2811_ADCSR_ADMODE(x)          (((x) & 0x3) << 0)

#define DT2811_ADGCR_REG                0x01    /* r/w  A/D Gain/Channel */
#define DT2811_ADGCR_GAIN(x)            (((x) & 0x3) << 6)
#define DT2811_ADGCR_CHAN(x)            (((x) & 0xf) << 0)

#define DT2811_ADDATA_LO_REG            0x02    /* r   A/D Data low byte */
#define DT2811_ADDATA_HI_REG            0x03    /* r   A/D Data high byte */

#define DT2811_DADATA_LO_REG(x)         (0x02 + ((x) * 2)) /* w D/A Data low */
#define DT2811_DADATA_HI_REG(x)         (0x03 + ((x) * 2)) /* w D/A Data high */

#define DT2811_DI_REG                   0x06    /* r   Digital Input Port 0 */
#define DT2811_DO_REG                   0x06    /* w   Digital Output Port 1 */

#define DT2811_TMRCTR_REG               0x07    /* r/w  Timer/Counter */
#define DT2811_TMRCTR_MANTISSA(x)       (((x) & 0x7) << 3)
#define DT2811_TMRCTR_EXPONENT(x)       (((x) & 0x7) << 0)

#define DT2811_OSC_BASE                 1666    /* 600 kHz = 1666.6667ns */

/*
 * Timer frequency control:
 *   DT2811_TMRCTR_MANTISSA     DT2811_TMRCTR_EXPONENT
 *   val  divisor  frequency    val  multiply divisor/divide frequency by
 *    0      1      600 kHz      0   1
 *    1     10       60 kHz      1   10
 *    2      2      300 kHz      2   100
 *    3      3      200 kHz      3   1000
 *    4      4      150 kHz      4   10000
 *    5      5      120 kHz      5   100000
 *    6      6      100 kHz      6   1000000
 *    7     12       50 kHz      7   10000000
 */
static const unsigned int dt2811_clk_dividers[] = {
        1, 10, 2, 3, 4, 5, 6, 12
};

static const unsigned int dt2811_clk_multipliers[] = {
        1, 10, 100, 1000, 10000, 100000, 1000000, 10000000
};

/*
 * The Analog Input range is set using jumpers on the board.
 *
 * Input Range          W9  W10
 * -5V to +5V           In  Out
 * -2.5V to +2.5V       In  In
 * 0V to +5V            Out In
 *
 * The gain may be set to 1, 2, 4, or 8 (on the dt2811-pgh) or to
 * 1, 10, 100, 500 (on the dt2811-pgl).
 */
static const struct comedi_lrange dt2811_pgh_ai_ranges = {
        12, {
                BIP_RANGE(5),           /* range 0: gain=1 */
                BIP_RANGE(2.5),         /* range 1: gain=2 */
                BIP_RANGE(1.25),        /* range 2: gain=4 */
                BIP_RANGE(0.625),       /* range 3: gain=8 */

                BIP_RANGE(2.5),         /* range 0+4: gain=1 */
                BIP_RANGE(1.25),        /* range 1+4: gain=2 */
                BIP_RANGE(0.625),       /* range 2+4: gain=4 */
                BIP_RANGE(0.3125),      /* range 3+4: gain=8 */

                UNI_RANGE(5),           /* range 0+8: gain=1 */
                UNI_RANGE(2.5),         /* range 1+8: gain=2 */
                UNI_RANGE(1.25),        /* range 2+8: gain=4 */
                UNI_RANGE(0.625)        /* range 3+8: gain=8 */
        }
};

static const struct comedi_lrange dt2811_pgl_ai_ranges = {
        12, {
                BIP_RANGE(5),           /* range 0: gain=1 */
                BIP_RANGE(0.5),         /* range 1: gain=10 */
                BIP_RANGE(0.05),        /* range 2: gain=100 */
                BIP_RANGE(0.01),        /* range 3: gain=500 */

                BIP_RANGE(2.5),         /* range 0+4: gain=1 */
                BIP_RANGE(0.25),        /* range 1+4: gain=10 */
                BIP_RANGE(0.025),       /* range 2+4: gain=100 */
                BIP_RANGE(0.005),       /* range 3+4: gain=500 */

                UNI_RANGE(5),           /* range 0+8: gain=1 */
                UNI_RANGE(0.5),         /* range 1+8: gain=10 */
                UNI_RANGE(0.05),        /* range 2+8: gain=100 */
                UNI_RANGE(0.01)         /* range 3+8: gain=500 */
        }
};

/*
 * The Analog Output range is set per-channel using jumpers on the board.
 *
 *                      DAC0 Jumpers            DAC1 Jumpers
 * Output Range         W5  W6  W7  W8          W1  W2  W3  W4
 * -5V to +5V           In  Out In  Out         In  Out In  Out
 * -2.5V to +2.5V       In  Out Out In          In  Out Out In
 * 0 to +5V             Out In  Out In          Out In  Out In
 */
static const struct comedi_lrange dt2811_ao_ranges = {
        3, {
                BIP_RANGE(5),   /* default setting from factory */
                BIP_RANGE(2.5),
                UNI_RANGE(5)
        }
};

struct dt2811_board {
        const char *name;
        unsigned int is_pgh:1;
};

static const struct dt2811_board dt2811_boards[] = {
        {
                .name           = "dt2811-pgh",
                .is_pgh         = 1,
        }, {
                .name           = "dt2811-pgl",
        },
};

struct dt2811_private {
        unsigned int ai_divisor;
};

static unsigned int dt2811_ai_read_sample(struct comedi_device *dev,
                                          struct comedi_subdevice *s)
{
        unsigned int val;

        val = inb(dev->iobase + DT2811_ADDATA_LO_REG) |
              (inb(dev->iobase + DT2811_ADDATA_HI_REG) << 8);

        return val & s->maxdata;
}

static irqreturn_t dt2811_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;

        if (!dev->attached)
                return IRQ_NONE;

        status = inb(dev->iobase + DT2811_ADCSR_REG);

        if (status & DT2811_ADCSR_ADERROR) {
                async->events |= COMEDI_CB_OVERFLOW;

                outb(status | DT2811_ADCSR_CLRERROR,
                     dev->iobase + DT2811_ADCSR_REG);
        }

        if (status & DT2811_ADCSR_ADDONE) {
                unsigned short val;

                val = dt2811_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;

        comedi_handle_events(dev, s);

        return IRQ_HANDLED;
}

static int dt2811_ai_cancel(struct comedi_device *dev,
                            struct comedi_subdevice *s)
{
        /*
         * Mode 0
         * Single conversion
         *
         * Loading a chanspec will trigger a conversion.
         */
        outb(DT2811_ADCSR_ADMODE(0), dev->iobase + DT2811_ADCSR_REG);

        return 0;
}

static void dt2811_ai_set_chanspec(struct comedi_device *dev,
                                   unsigned int chanspec)
{
        unsigned int chan = CR_CHAN(chanspec);
        unsigned int range = CR_RANGE(chanspec);

        outb(DT2811_ADGCR_CHAN(chan) | DT2811_ADGCR_GAIN(range),
             dev->iobase + DT2811_ADGCR_REG);
}

static int dt2811_ai_cmd(struct comedi_device *dev,
                         struct comedi_subdevice *s)
{
        struct dt2811_private *devpriv = dev->private;
        struct comedi_cmd *cmd = &s->async->cmd;
        unsigned int mode;

        if (cmd->start_src == TRIG_NOW) {
                /*
                 * Mode 1
                 * Continuous conversion, internal trigger and clock
                 *
                 * This resets the trigger flip-flop, disabling A/D strobes.
                 * The timer/counter register is loaded with the division
                 * ratio which will give the required sample rate.
                 *
                 * Loading the first chanspec sets the trigger flip-flop,
                 * enabling the timer/counter. A/D strobes are then generated
                 * at the rate set by the internal clock/divider.
                 */
                mode = DT2811_ADCSR_ADMODE(1);
        } else { /* TRIG_EXT */
                if (cmd->convert_src == TRIG_TIMER) {
                        /*
                         * Mode 2
                         * Continuous conversion, external trigger
                         *
                         * Similar to Mode 1, with the exception that the
                         * trigger flip-flop must be set by a negative edge
                         * on the external trigger input.
                         */
                        mode = DT2811_ADCSR_ADMODE(2);
                } else { /* TRIG_EXT */
                        /*
                         * Mode 3
                         * Continuous conversion, external trigger, clock
                         *
                         * Similar to Mode 2, with the exception that the
                         * conversion rate is set by the frequency on the
                         * external clock/divider.
                         */
                        mode = DT2811_ADCSR_ADMODE(3);
                }
        }
        outb(mode | DT2811_ADCSR_INTENB, dev->iobase + DT2811_ADCSR_REG);

        /* load timer */
        outb(devpriv->ai_divisor, dev->iobase + DT2811_TMRCTR_REG);

        /* load chanspec - enables timer */
        dt2811_ai_set_chanspec(dev, cmd->chanlist[0]);

        return 0;
}

static unsigned int dt2811_ns_to_timer(unsigned int *nanosec,
                                       unsigned int flags)
{
        unsigned long long ns;
        unsigned int ns_lo = COMEDI_MIN_SPEED;
        unsigned int ns_hi = 0;
        unsigned int divisor_hi = 0;
        unsigned int divisor_lo = 0;
        unsigned int _div;
        unsigned int _mult;

        /*
         * Work through all the divider/multiplier values to find the two
         * closest divisors to generate the requested nanosecond timing.
         */
        for (_div = 0; _div <= 7; _div++) {
                for (_mult = 0; _mult <= 7; _mult++) {
                        unsigned int div = dt2811_clk_dividers[_div];
                        unsigned int mult = dt2811_clk_multipliers[_mult];
                        unsigned long long divider = div * mult;
                        unsigned int divisor = DT2811_TMRCTR_MANTISSA(_div) |
                                               DT2811_TMRCTR_EXPONENT(_mult);

                        /*
                         * The timer can be configured to run at a slowest
                         * speed of 0.005hz (600 Khz/120000000), which requires
                         * 37-bits to represent the nanosecond value. Limit the
                         * slowest timing to what comedi handles (32-bits).
                         */
                        ns = divider * DT2811_OSC_BASE;
                        if (ns > COMEDI_MIN_SPEED)
                                continue;

                        /* Check for fastest found timing */
                        if (ns <= *nanosec && ns > ns_hi) {
                                ns_hi = ns;
                                divisor_hi = divisor;
                        }
                        /* Check for slowest found timing */
                        if (ns >= *nanosec && ns < ns_lo) {
                                ns_lo = ns;
                                divisor_lo = divisor;
                        }
                }
        }

        /*
         * The slowest found timing will be invalid if the requested timing
         * is faster than what can be generated by the timer. Fix it so that
         * CMDF_ROUND_UP returns valid timing.
         */
        if (ns_lo == COMEDI_MIN_SPEED) {
                ns_lo = ns_hi;
                divisor_lo = divisor_hi;
        }
        /*
         * The fastest found timing will be invalid if the requested timing
         * is less than what can be generated by the timer. Fix it so that
         * CMDF_ROUND_NEAREST and CMDF_ROUND_DOWN return valid timing.
         */
        if (ns_hi == 0) {
                ns_hi = ns_lo;
                divisor_hi = divisor_lo;
        }

        switch (flags & CMDF_ROUND_MASK) {
        case CMDF_ROUND_NEAREST:
        default:
                if (ns_hi - *nanosec < *nanosec - ns_lo) {
                        *nanosec = ns_lo;
                        return divisor_lo;
                }
                *nanosec = ns_hi;
                return divisor_hi;
        case CMDF_ROUND_UP:
                *nanosec = ns_lo;
                return divisor_lo;
        case CMDF_ROUND_DOWN:
                *nanosec = ns_hi;
                return divisor_hi;
        }
}

static int dt2811_ai_cmdtest(struct comedi_device *dev,
                             struct comedi_subdevice *s,
                             struct comedi_cmd *cmd)
{
        struct dt2811_private *devpriv = dev->private;
        unsigned int arg;
        int err = 0;

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

        err |= comedi_check_trigger_src(&cmd->start_src, TRIG_NOW | TRIG_EXT);
        err |= comedi_check_trigger_src(&cmd->scan_begin_src, TRIG_FOLLOW);
        err |= comedi_check_trigger_src(&cmd->convert_src,
                                        TRIG_TIMER | TRIG_EXT);
        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->start_src);
        err |= comedi_check_trigger_is_unique(cmd->convert_src);
        err |= comedi_check_trigger_is_unique(cmd->stop_src);

        /* Step 2b : and mutually compatible */

        if (cmd->convert_src == TRIG_EXT && cmd->start_src != TRIG_EXT)
                err |= -EINVAL;

        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);
        if (cmd->convert_src == TRIG_TIMER)
                err |= comedi_check_trigger_arg_min(&cmd->convert_arg, 12500);
        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 */

        if (cmd->convert_src == TRIG_TIMER) {
                arg = cmd->convert_arg;
                devpriv->ai_divisor = dt2811_ns_to_timer(&arg, cmd->flags);
                err |= comedi_check_trigger_arg_is(&cmd->convert_arg, arg);
        } else { /* TRIG_EXT */
                /* The convert_arg is used to set the divisor. */
                devpriv->ai_divisor = cmd->convert_arg;
        }

        if (err)
                return 4;

        /* Step 5: check channel list if it exists */

        return 0;
}

static int dt2811_ai_eoc(struct comedi_device *dev,
                         struct comedi_subdevice *s,
                         struct comedi_insn *insn,
                         unsigned long context)
{
        unsigned int status;

        status = inb(dev->iobase + DT2811_ADCSR_REG);
        if ((status & DT2811_ADCSR_ADBUSY) == 0)
                return 0;
        return -EBUSY;
}

static int dt2811_ai_insn_read(struct comedi_device *dev,
                               struct comedi_subdevice *s,
                               struct comedi_insn *insn,
                               unsigned int *data)
{
        int ret;
        int i;

        /* We will already be in Mode 0 */
        for (i = 0; i < insn->n; i++) {
                /* load chanspec and trigger conversion */
                dt2811_ai_set_chanspec(dev, insn->chanspec);

                ret = comedi_timeout(dev, s, insn, dt2811_ai_eoc, 0);
                if (ret)
                        return ret;

                data[i] = dt2811_ai_read_sample(dev, s);
        }

        return insn->n;
}

static int dt2811_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 val = s->readback[chan];
        int i;

        for (i = 0; i < insn->n; i++) {
                val = data[i];
                outb(val & 0xff, dev->iobase + DT2811_DADATA_LO_REG(chan));
                outb((val >> 8) & 0xff,
                     dev->iobase + DT2811_DADATA_HI_REG(chan));
        }
        s->readback[chan] = val;

        return insn->n;
}

static int dt2811_di_insn_bits(struct comedi_device *dev,
                               struct comedi_subdevice *s,
                               struct comedi_insn *insn,
                               unsigned int *data)
{
        data[1] = inb(dev->iobase + DT2811_DI_REG);

        return insn->n;
}

static int dt2811_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 + DT2811_DO_REG);

        data[1] = s->state;

        return insn->n;
}

static void dt2811_reset(struct comedi_device *dev)
{
        /* This is the initialization sequence from the users manual */
        outb(DT2811_ADCSR_ADMODE(0), dev->iobase + DT2811_ADCSR_REG);
        usleep_range(100, 1000);
        inb(dev->iobase + DT2811_ADDATA_LO_REG);
        inb(dev->iobase + DT2811_ADDATA_HI_REG);
        outb(DT2811_ADCSR_ADMODE(0) | DT2811_ADCSR_CLRERROR,
             dev->iobase + DT2811_ADCSR_REG);
}

static int dt2811_attach(struct comedi_device *dev, struct comedi_devconfig *it)
{
        const struct dt2811_board *board = dev->board_ptr;
        struct dt2811_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], 0x8);
        if (ret)
                return ret;

        dt2811_reset(dev);

        /* IRQ's 2,3,5,7 are valid for async command support */
        if (it->options[1] <= 7  && (BIT(it->options[1]) & 0xac)) {
                ret = request_irq(it->options[1], dt2811_interrupt, 0,
                                  dev->board_name, dev);
                if (ret == 0)
                        dev->irq = it->options[1];
        }

        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 |
                          ((it->options[2] == 1) ? SDF_DIFF :
                           (it->options[2] == 2) ? SDF_COMMON : SDF_GROUND);
        s->n_chan       = (it->options[2] == 1) ? 8 : 16;
        s->maxdata      = 0x0fff;
        s->range_table  = board->is_pgh ? &dt2811_pgh_ai_ranges
                                        : &dt2811_pgl_ai_ranges;
        s->insn_read    = dt2811_ai_insn_read;
        if (dev->irq) {
                dev->read_subdev = s;
                s->subdev_flags |= SDF_CMD_READ;
                s->len_chanlist = 1;
                s->do_cmdtest   = dt2811_ai_cmdtest;
                s->do_cmd       = dt2811_ai_cmd;
                s->cancel       = dt2811_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      = 0x0fff;
        s->range_table  = &dt2811_ao_ranges;
        s->insn_write   = dt2811_ao_insn_write;

        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    = dt2811_di_insn_bits;

        /* Digital Output 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    = dt2811_do_insn_bits;

        return 0;
}

static struct comedi_driver dt2811_driver = {
        .driver_name    = "dt2811",
        .module         = THIS_MODULE,
        .attach         = dt2811_attach,
        .detach         = comedi_legacy_detach,
        .board_name     = &dt2811_boards[0].name,
        .num_names      = ARRAY_SIZE(dt2811_boards),
        .offset         = sizeof(struct dt2811_board),
};
module_comedi_driver(dt2811_driver);

MODULE_AUTHOR("Comedi https://www.comedi.org");
MODULE_DESCRIPTION("Comedi driver for Data Translation DT2811 series boards");
MODULE_LICENSE("GPL");