/*
    comedi/drivers/amplc_dio200_common.c

    Common support code for "amplc_dio200" and "amplc_dio200_pci".

    Copyright (C) 2005-2013 MEV Ltd. <http://www.mev.co.uk/>

    COMEDI - Linux Control and Measurement Device Interface
    Copyright (C) 1998,2000 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.
*/

#include <linux/interrupt.h>
#include <linux/slab.h>

#include "../comedidev.h"

#include "amplc_dio200.h"
#include "comedi_fc.h"
#include "8253.h"

/* 8255 control register bits */
#define CR_C_LO_IO      0x01
#define CR_B_IO         0x02
#define CR_B_MODE       0x04
#define CR_C_HI_IO      0x08
#define CR_A_IO         0x10
#define CR_A_MODE(a)    ((a)<<5)
#define CR_CW           0x80

/* 200 series registers */
#define DIO200_IO_SIZE          0x20
#define DIO200_PCIE_IO_SIZE     0x4000
#define DIO200_XCLK_SCE         0x18    /* Group X clock selection register */
#define DIO200_YCLK_SCE         0x19    /* Group Y clock selection register */
#define DIO200_ZCLK_SCE         0x1a    /* Group Z clock selection register */
#define DIO200_XGAT_SCE         0x1b    /* Group X gate selection register */
#define DIO200_YGAT_SCE         0x1c    /* Group Y gate selection register */
#define DIO200_ZGAT_SCE         0x1d    /* Group Z gate selection register */
#define DIO200_INT_SCE          0x1e    /* Interrupt enable/status register */
/* Extra registers for new PCIe boards */
#define DIO200_ENHANCE          0x20    /* 1 to enable enhanced features */
#define DIO200_VERSION          0x24    /* Hardware version register */
#define DIO200_TS_CONFIG        0x600   /* Timestamp timer config register */
#define DIO200_TS_COUNT         0x602   /* Timestamp timer count register */

/*
 * Functions for constructing value for DIO_200_?CLK_SCE and
 * DIO_200_?GAT_SCE registers:
 *
 * 'which' is: 0 for CTR-X1, CTR-Y1, CTR-Z1; 1 for CTR-X2, CTR-Y2 or CTR-Z2.
 * 'chan' is the channel: 0, 1 or 2.
 * 'source' is the signal source: 0 to 7, or 0 to 31 for "enhanced" boards.
 */
static unsigned char clk_gat_sce(unsigned int which, unsigned int chan,
                                 unsigned int source)
{
        return (which << 5) | (chan << 3) |
               ((source & 030) << 3) | (source & 007);
}

static unsigned char clk_sce(unsigned int which, unsigned int chan,
                             unsigned int source)
{
        return clk_gat_sce(which, chan, source);
}

static unsigned char gat_sce(unsigned int which, unsigned int chan,
                             unsigned int source)
{
        return clk_gat_sce(which, chan, source);
}

/*
 * Periods of the internal clock sources in nanoseconds.
 */
static const unsigned int clock_period[32] = {
        [1] = 100,              /* 10 MHz */
        [2] = 1000,             /* 1 MHz */
        [3] = 10000,            /* 100 kHz */
        [4] = 100000,           /* 10 kHz */
        [5] = 1000000,          /* 1 kHz */
        [11] = 50,              /* 20 MHz (enhanced boards) */
        /* clock sources 12 and later reserved for enhanced boards */
};

/*
 * Timestamp timer configuration register (for new PCIe boards).
 */
#define TS_CONFIG_RESET         0x100   /* Reset counter to zero. */
#define TS_CONFIG_CLK_SRC_MASK  0x0FF   /* Clock source. */
#define TS_CONFIG_MAX_CLK_SRC   2       /* Maximum clock source value. */

/*
 * Periods of the timestamp timer clock sources in nanoseconds.
 */
static const unsigned int ts_clock_period[TS_CONFIG_MAX_CLK_SRC + 1] = {
        1,                      /* 1 nanosecond (but with 20 ns granularity). */
        1000,                   /* 1 microsecond. */
        1000000,                /* 1 millisecond. */
};

struct dio200_subdev_8254 {
        unsigned int ofs;               /* Counter base offset */
        unsigned int clk_sce_ofs;       /* CLK_SCE base address */
        unsigned int gat_sce_ofs;       /* GAT_SCE base address */
        int which;                      /* Bit 5 of CLK_SCE or GAT_SCE */
        unsigned int clock_src[3];      /* Current clock sources */
        unsigned int gate_src[3];       /* Current gate sources */
        spinlock_t spinlock;
};

struct dio200_subdev_8255 {
        unsigned int ofs;               /* DIO base offset */
};

struct dio200_subdev_intr {
        spinlock_t spinlock;
        unsigned int ofs;
        unsigned int valid_isns;
        unsigned int enabled_isns;
        unsigned int stopcount;
        bool active:1;
        bool continuous:1;
};

static inline const struct dio200_layout *
dio200_board_layout(const struct dio200_board *board)
{
        return &board->layout;
}

static inline const struct dio200_layout *
dio200_dev_layout(struct comedi_device *dev)
{
        return dio200_board_layout(comedi_board(dev));
}

/*
 * Read 8-bit register.
 */
static unsigned char dio200_read8(struct comedi_device *dev,
                                  unsigned int offset)
{
        const struct dio200_board *thisboard = comedi_board(dev);
        struct dio200_private *devpriv = dev->private;

        offset <<= thisboard->mainshift;
        if (devpriv->io.regtype == io_regtype)
                return inb(devpriv->io.u.iobase + offset);
        else
                return readb(devpriv->io.u.membase + offset);
}

/*
 * Write 8-bit register.
 */
static void dio200_write8(struct comedi_device *dev, unsigned int offset,
                          unsigned char val)
{
        const struct dio200_board *thisboard = comedi_board(dev);
        struct dio200_private *devpriv = dev->private;

        offset <<= thisboard->mainshift;
        if (devpriv->io.regtype == io_regtype)
                outb(val, devpriv->io.u.iobase + offset);
        else
                writeb(val, devpriv->io.u.membase + offset);
}

/*
 * Read 32-bit register.
 */
static unsigned int dio200_read32(struct comedi_device *dev,
                                  unsigned int offset)
{
        const struct dio200_board *thisboard = comedi_board(dev);
        struct dio200_private *devpriv = dev->private;

        offset <<= thisboard->mainshift;
        if (devpriv->io.regtype == io_regtype)
                return inl(devpriv->io.u.iobase + offset);
        else
                return readl(devpriv->io.u.membase + offset);
}

/*
 * Write 32-bit register.
 */
static void dio200_write32(struct comedi_device *dev, unsigned int offset,
                           unsigned int val)
{
        const struct dio200_board *thisboard = comedi_board(dev);
        struct dio200_private *devpriv = dev->private;

        offset <<= thisboard->mainshift;
        if (devpriv->io.regtype == io_regtype)
                outl(val, devpriv->io.u.iobase + offset);
        else
                writel(val, devpriv->io.u.membase + offset);
}

/*
 * 'insn_bits' function for an 'INTERRUPT' subdevice.
 */
static int
dio200_subdev_intr_insn_bits(struct comedi_device *dev,
                             struct comedi_subdevice *s,
                             struct comedi_insn *insn, unsigned int *data)
{
        const struct dio200_layout *layout = dio200_dev_layout(dev);
        struct dio200_subdev_intr *subpriv = s->private;

        if (layout->has_int_sce) {
                /* Just read the interrupt status register.  */
                data[1] = dio200_read8(dev, subpriv->ofs) & subpriv->valid_isns;
        } else {
                /* No interrupt status register. */
                data[0] = 0;
        }

        return insn->n;
}

/*
 * Called to stop acquisition for an 'INTERRUPT' subdevice.
 */
static void dio200_stop_intr(struct comedi_device *dev,
                             struct comedi_subdevice *s)
{
        const struct dio200_layout *layout = dio200_dev_layout(dev);
        struct dio200_subdev_intr *subpriv = s->private;

        subpriv->active = false;
        subpriv->enabled_isns = 0;
        if (layout->has_int_sce)
                dio200_write8(dev, subpriv->ofs, 0);
}

/*
 * Called to start acquisition for an 'INTERRUPT' subdevice.
 */
static int dio200_start_intr(struct comedi_device *dev,
                             struct comedi_subdevice *s)
{
        unsigned int n;
        unsigned isn_bits;
        const struct dio200_layout *layout = dio200_dev_layout(dev);
        struct dio200_subdev_intr *subpriv = s->private;
        struct comedi_cmd *cmd = &s->async->cmd;
        int retval = 0;

        if (!subpriv->continuous && subpriv->stopcount == 0) {
                /* An empty acquisition! */
                s->async->events |= COMEDI_CB_EOA;
                subpriv->active = false;
                retval = 1;
        } else {
                /* Determine interrupt sources to enable. */
                isn_bits = 0;
                if (cmd->chanlist) {
                        for (n = 0; n < cmd->chanlist_len; n++)
                                isn_bits |= (1U << CR_CHAN(cmd->chanlist[n]));
                }
                isn_bits &= subpriv->valid_isns;
                /* Enable interrupt sources. */
                subpriv->enabled_isns = isn_bits;
                if (layout->has_int_sce)
                        dio200_write8(dev, subpriv->ofs, isn_bits);
        }

        return retval;
}

/*
 * Internal trigger function to start acquisition for an 'INTERRUPT' subdevice.
 */
static int
dio200_inttrig_start_intr(struct comedi_device *dev, struct comedi_subdevice *s,
                          unsigned int trignum)
{
        struct dio200_subdev_intr *subpriv;
        unsigned long flags;
        int event = 0;

        if (trignum != 0)
                return -EINVAL;

        subpriv = s->private;

        spin_lock_irqsave(&subpriv->spinlock, flags);
        s->async->inttrig = NULL;
        if (subpriv->active)
                event = dio200_start_intr(dev, s);

        spin_unlock_irqrestore(&subpriv->spinlock, flags);

        if (event)
                comedi_event(dev, s);

        return 1;
}

static void dio200_read_scan_intr(struct comedi_device *dev,
                                  struct comedi_subdevice *s,
                                  unsigned int triggered)
{
        struct dio200_subdev_intr *subpriv = s->private;
        unsigned short val;
        unsigned int n, ch, len;

        val = 0;
        len = s->async->cmd.chanlist_len;
        for (n = 0; n < len; n++) {
                ch = CR_CHAN(s->async->cmd.chanlist[n]);
                if (triggered & (1U << ch))
                        val |= (1U << n);
        }
        /* Write the scan to the buffer. */
        if (comedi_buf_put(s->async, val)) {
                s->async->events |= (COMEDI_CB_BLOCK | COMEDI_CB_EOS);
        } else {
                /* Error!  Stop acquisition.  */
                dio200_stop_intr(dev, s);
                s->async->events |= COMEDI_CB_ERROR | COMEDI_CB_OVERFLOW;
                comedi_error(dev, "buffer overflow");
        }

        /* Check for end of acquisition. */
        if (!subpriv->continuous) {
                /* stop_src == TRIG_COUNT */
                if (subpriv->stopcount > 0) {
                        subpriv->stopcount--;
                        if (subpriv->stopcount == 0) {
                                s->async->events |= COMEDI_CB_EOA;
                                dio200_stop_intr(dev, s);
                        }
                }
        }
}

/*
 * This is called from the interrupt service routine to handle a read
 * scan on an 'INTERRUPT' subdevice.
 */
static int dio200_handle_read_intr(struct comedi_device *dev,
                                   struct comedi_subdevice *s)
{
        const struct dio200_layout *layout = dio200_dev_layout(dev);
        struct dio200_subdev_intr *subpriv = s->private;
        unsigned triggered;
        unsigned intstat;
        unsigned cur_enabled;
        unsigned int oldevents;
        unsigned long flags;

        triggered = 0;

        spin_lock_irqsave(&subpriv->spinlock, flags);
        oldevents = s->async->events;
        if (layout->has_int_sce) {
                /*
                 * Collect interrupt sources that have triggered and disable
                 * them temporarily.  Loop around until no extra interrupt
                 * sources have triggered, at which point, the valid part of
                 * the interrupt status register will read zero, clearing the
                 * cause of the interrupt.
                 *
                 * Mask off interrupt sources already seen to avoid infinite
                 * loop in case of misconfiguration.
                 */
                cur_enabled = subpriv->enabled_isns;
                while ((intstat = (dio200_read8(dev, subpriv->ofs) &
                                   subpriv->valid_isns & ~triggered)) != 0) {
                        triggered |= intstat;
                        cur_enabled &= ~triggered;
                        dio200_write8(dev, subpriv->ofs, cur_enabled);
                }
        } else {
                /*
                 * No interrupt status register.  Assume the single interrupt
                 * source has triggered.
                 */
                triggered = subpriv->enabled_isns;
        }

        if (triggered) {
                /*
                 * Some interrupt sources have triggered and have been
                 * temporarily disabled to clear the cause of the interrupt.
                 *
                 * Reenable them NOW to minimize the time they are disabled.
                 */
                cur_enabled = subpriv->enabled_isns;
                if (layout->has_int_sce)
                        dio200_write8(dev, subpriv->ofs, cur_enabled);

                if (subpriv->active) {
                        /*
                         * The command is still active.
                         *
                         * Ignore interrupt sources that the command isn't
                         * interested in (just in case there's a race
                         * condition).
                         */
                        if (triggered & subpriv->enabled_isns)
                                /* Collect scan data. */
                                dio200_read_scan_intr(dev, s, triggered);
                }
        }
        spin_unlock_irqrestore(&subpriv->spinlock, flags);

        if (oldevents != s->async->events)
                comedi_event(dev, s);

        return (triggered != 0);
}

/*
 * 'cancel' function for an 'INTERRUPT' subdevice.
 */
static int dio200_subdev_intr_cancel(struct comedi_device *dev,
                                     struct comedi_subdevice *s)
{
        struct dio200_subdev_intr *subpriv = s->private;
        unsigned long flags;

        spin_lock_irqsave(&subpriv->spinlock, flags);
        if (subpriv->active)
                dio200_stop_intr(dev, s);

        spin_unlock_irqrestore(&subpriv->spinlock, flags);

        return 0;
}

/*
 * 'do_cmdtest' function for an 'INTERRUPT' subdevice.
 */
static int
dio200_subdev_intr_cmdtest(struct comedi_device *dev,
                           struct comedi_subdevice *s, struct comedi_cmd *cmd)
{
        int err = 0;

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

        err |= cfc_check_trigger_src(&cmd->start_src, TRIG_NOW | TRIG_INT);
        err |= cfc_check_trigger_src(&cmd->scan_begin_src, TRIG_EXT);
        err |= cfc_check_trigger_src(&cmd->convert_src, TRIG_NOW);
        err |= cfc_check_trigger_src(&cmd->scan_end_src, TRIG_COUNT);
        err |= cfc_check_trigger_src(&cmd->stop_src, TRIG_COUNT | TRIG_NONE);

        if (err)
                return 1;

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

        err |= cfc_check_trigger_is_unique(cmd->start_src);
        err |= cfc_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 |= cfc_check_trigger_arg_is(&cmd->start_arg, 0);
        err |= cfc_check_trigger_arg_is(&cmd->scan_begin_arg, 0);
        err |= cfc_check_trigger_arg_is(&cmd->convert_arg, 0);
        err |= cfc_check_trigger_arg_is(&cmd->scan_end_arg, cmd->chanlist_len);

        switch (cmd->stop_src) {
        case TRIG_COUNT:
                /* any count allowed */
                break;
        case TRIG_NONE:
                err |= cfc_check_trigger_arg_is(&cmd->stop_arg, 0);
                break;
        default:
                break;
        }

        if (err)
                return 3;

        /* step 4: fix up any arguments */

        /* if (err) return 4; */

        return 0;
}

/*
 * 'do_cmd' function for an 'INTERRUPT' subdevice.
 */
static int dio200_subdev_intr_cmd(struct comedi_device *dev,
                                  struct comedi_subdevice *s)
{
        struct comedi_cmd *cmd = &s->async->cmd;
        struct dio200_subdev_intr *subpriv = s->private;
        unsigned long flags;
        int event = 0;

        spin_lock_irqsave(&subpriv->spinlock, flags);
        subpriv->active = 1;

        /* Set up end of acquisition. */
        switch (cmd->stop_src) {
        case TRIG_COUNT:
                subpriv->continuous = false;
                subpriv->stopcount = cmd->stop_arg;
                break;
        default:
                /* TRIG_NONE */
                subpriv->continuous = true;
                subpriv->stopcount = 0;
                break;
        }

        /* Set up start of acquisition. */
        switch (cmd->start_src) {
        case TRIG_INT:
                s->async->inttrig = dio200_inttrig_start_intr;
                break;
        default:
                /* TRIG_NOW */
                event = dio200_start_intr(dev, s);
                break;
        }
        spin_unlock_irqrestore(&subpriv->spinlock, flags);

        if (event)
                comedi_event(dev, s);

        return 0;
}

/*
 * This function initializes an 'INTERRUPT' subdevice.
 */
static int
dio200_subdev_intr_init(struct comedi_device *dev, struct comedi_subdevice *s,
                        unsigned int offset, unsigned valid_isns)
{
        const struct dio200_layout *layout = dio200_dev_layout(dev);
        struct dio200_subdev_intr *subpriv;

        subpriv = comedi_alloc_spriv(s, sizeof(*subpriv));
        if (!subpriv)
                return -ENOMEM;

        subpriv->ofs = offset;
        subpriv->valid_isns = valid_isns;
        spin_lock_init(&subpriv->spinlock);

        if (layout->has_int_sce)
                /* Disable interrupt sources. */
                dio200_write8(dev, subpriv->ofs, 0);

        s->type = COMEDI_SUBD_DI;
        s->subdev_flags = SDF_READABLE | SDF_CMD_READ;
        if (layout->has_int_sce) {
                s->n_chan = DIO200_MAX_ISNS;
                s->len_chanlist = DIO200_MAX_ISNS;
        } else {
                /* No interrupt source register.  Support single channel. */
                s->n_chan = 1;
                s->len_chanlist = 1;
        }
        s->range_table = &range_digital;
        s->maxdata = 1;
        s->insn_bits = dio200_subdev_intr_insn_bits;
        s->do_cmdtest = dio200_subdev_intr_cmdtest;
        s->do_cmd = dio200_subdev_intr_cmd;
        s->cancel = dio200_subdev_intr_cancel;

        return 0;
}

/*
 * Interrupt service routine.
 */
static irqreturn_t dio200_interrupt(int irq, void *d)
{
        struct comedi_device *dev = d;
        struct dio200_private *devpriv = dev->private;
        struct comedi_subdevice *s;
        int handled;

        if (!dev->attached)
                return IRQ_NONE;

        if (devpriv->intr_sd >= 0) {
                s = &dev->subdevices[devpriv->intr_sd];
                handled = dio200_handle_read_intr(dev, s);
        } else {
                handled = 0;
        }

        return IRQ_RETVAL(handled);
}

/*
 * Read an '8254' counter subdevice channel.
 */
static unsigned int
dio200_subdev_8254_read_chan(struct comedi_device *dev,
                             struct comedi_subdevice *s, unsigned int chan)
{
        struct dio200_subdev_8254 *subpriv = s->private;
        unsigned int val;

        /* latch counter */
        val = chan << 6;
        dio200_write8(dev, subpriv->ofs + i8254_control_reg, val);
        /* read lsb, msb */
        val = dio200_read8(dev, subpriv->ofs + chan);
        val += dio200_read8(dev, subpriv->ofs + chan) << 8;
        return val;
}

/*
 * Write an '8254' subdevice channel.
 */
static void
dio200_subdev_8254_write_chan(struct comedi_device *dev,
                              struct comedi_subdevice *s, unsigned int chan,
                              unsigned int count)
{
        struct dio200_subdev_8254 *subpriv = s->private;

        /* write lsb, msb */
        dio200_write8(dev, subpriv->ofs + chan, count & 0xff);
        dio200_write8(dev, subpriv->ofs + chan, (count >> 8) & 0xff);
}

/*
 * Set mode of an '8254' subdevice channel.
 */
static void
dio200_subdev_8254_set_mode(struct comedi_device *dev,
                            struct comedi_subdevice *s, unsigned int chan,
                            unsigned int mode)
{
        struct dio200_subdev_8254 *subpriv = s->private;
        unsigned int byte;

        byte = chan << 6;
        byte |= 0x30;           /* access order: lsb, msb */
        byte |= (mode & 0xf);   /* counter mode and BCD|binary */
        dio200_write8(dev, subpriv->ofs + i8254_control_reg, byte);
}

/*
 * Read status byte of an '8254' counter subdevice channel.
 */
static unsigned int
dio200_subdev_8254_status(struct comedi_device *dev,
                          struct comedi_subdevice *s, unsigned int chan)
{
        struct dio200_subdev_8254 *subpriv = s->private;

        /* latch status */
        dio200_write8(dev, subpriv->ofs + i8254_control_reg,
                      0xe0 | (2 << chan));
        /* read status */
        return dio200_read8(dev, subpriv->ofs + chan);
}

/*
 * Handle 'insn_read' for an '8254' counter subdevice.
 */
static int
dio200_subdev_8254_read(struct comedi_device *dev, struct comedi_subdevice *s,
                        struct comedi_insn *insn, unsigned int *data)
{
        struct dio200_subdev_8254 *subpriv = s->private;
        int chan = CR_CHAN(insn->chanspec);
        unsigned int n;
        unsigned long flags;

        for (n = 0; n < insn->n; n++) {
                spin_lock_irqsave(&subpriv->spinlock, flags);
                data[n] = dio200_subdev_8254_read_chan(dev, s, chan);
                spin_unlock_irqrestore(&subpriv->spinlock, flags);
        }
        return insn->n;
}

/*
 * Handle 'insn_write' for an '8254' counter subdevice.
 */
static int
dio200_subdev_8254_write(struct comedi_device *dev, struct comedi_subdevice *s,
                         struct comedi_insn *insn, unsigned int *data)
{
        struct dio200_subdev_8254 *subpriv = s->private;
        int chan = CR_CHAN(insn->chanspec);
        unsigned int n;
        unsigned long flags;

        for (n = 0; n < insn->n; n++) {
                spin_lock_irqsave(&subpriv->spinlock, flags);
                dio200_subdev_8254_write_chan(dev, s, chan, data[n]);
                spin_unlock_irqrestore(&subpriv->spinlock, flags);
        }
        return insn->n;
}

/*
 * Set gate source for an '8254' counter subdevice channel.
 */
static int
dio200_subdev_8254_set_gate_src(struct comedi_device *dev,
                                struct comedi_subdevice *s,
                                unsigned int counter_number,
                                unsigned int gate_src)
{
        const struct dio200_layout *layout = dio200_dev_layout(dev);
        struct dio200_subdev_8254 *subpriv = s->private;
        unsigned char byte;

        if (!layout->has_clk_gat_sce)
                return -1;
        if (counter_number > 2)
                return -1;
        if (gate_src > (layout->has_enhancements ? 31 : 7))
                return -1;

        subpriv->gate_src[counter_number] = gate_src;
        byte = gat_sce(subpriv->which, counter_number, gate_src);
        dio200_write8(dev, subpriv->gat_sce_ofs, byte);

        return 0;
}

/*
 * Get gate source for an '8254' counter subdevice channel.
 */
static int
dio200_subdev_8254_get_gate_src(struct comedi_device *dev,
                                struct comedi_subdevice *s,
                                unsigned int counter_number)
{
        const struct dio200_layout *layout = dio200_dev_layout(dev);
        struct dio200_subdev_8254 *subpriv = s->private;

        if (!layout->has_clk_gat_sce)
                return -1;
        if (counter_number > 2)
                return -1;

        return subpriv->gate_src[counter_number];
}

/*
 * Set clock source for an '8254' counter subdevice channel.
 */
static int
dio200_subdev_8254_set_clock_src(struct comedi_device *dev,
                                 struct comedi_subdevice *s,
                                 unsigned int counter_number,
                                 unsigned int clock_src)
{
        const struct dio200_layout *layout = dio200_dev_layout(dev);
        struct dio200_subdev_8254 *subpriv = s->private;
        unsigned char byte;

        if (!layout->has_clk_gat_sce)
                return -1;
        if (counter_number > 2)
                return -1;
        if (clock_src > (layout->has_enhancements ? 31 : 7))
                return -1;

        subpriv->clock_src[counter_number] = clock_src;
        byte = clk_sce(subpriv->which, counter_number, clock_src);
        dio200_write8(dev, subpriv->clk_sce_ofs, byte);

        return 0;
}

/*
 * Get clock source for an '8254' counter subdevice channel.
 */
static int
dio200_subdev_8254_get_clock_src(struct comedi_device *dev,
                                 struct comedi_subdevice *s,
                                 unsigned int counter_number,
                                 unsigned int *period_ns)
{
        const struct dio200_layout *layout = dio200_dev_layout(dev);
        struct dio200_subdev_8254 *subpriv = s->private;
        unsigned clock_src;

        if (!layout->has_clk_gat_sce)
                return -1;
        if (counter_number > 2)
                return -1;

        clock_src = subpriv->clock_src[counter_number];
        *period_ns = clock_period[clock_src];
        return clock_src;
}

/*
 * Handle 'insn_config' for an '8254' counter subdevice.
 */
static int
dio200_subdev_8254_config(struct comedi_device *dev, struct comedi_subdevice *s,
                          struct comedi_insn *insn, unsigned int *data)
{
        struct dio200_subdev_8254 *subpriv = s->private;
        int ret = 0;
        int chan = CR_CHAN(insn->chanspec);
        unsigned long flags;

        spin_lock_irqsave(&subpriv->spinlock, flags);
        switch (data[0]) {
        case INSN_CONFIG_SET_COUNTER_MODE:
                if (data[1] > (I8254_MODE5 | I8254_BINARY))
                        ret = -EINVAL;
                else
                        dio200_subdev_8254_set_mode(dev, s, chan, data[1]);
                break;
        case INSN_CONFIG_8254_READ_STATUS:
                data[1] = dio200_subdev_8254_status(dev, s, chan);
                break;
        case INSN_CONFIG_SET_GATE_SRC:
                ret = dio200_subdev_8254_set_gate_src(dev, s, chan, data[2]);
                if (ret < 0)
                        ret = -EINVAL;
                break;
        case INSN_CONFIG_GET_GATE_SRC:
                ret = dio200_subdev_8254_get_gate_src(dev, s, chan);
                if (ret < 0) {
                        ret = -EINVAL;
                        break;
                }
                data[2] = ret;
                break;
        case INSN_CONFIG_SET_CLOCK_SRC:
                ret = dio200_subdev_8254_set_clock_src(dev, s, chan, data[1]);
                if (ret < 0)
                        ret = -EINVAL;
                break;
        case INSN_CONFIG_GET_CLOCK_SRC:
                ret = dio200_subdev_8254_get_clock_src(dev, s, chan, &data[2]);
                if (ret < 0) {
                        ret = -EINVAL;
                        break;
                }
                data[1] = ret;
                break;
        default:
                ret = -EINVAL;
                break;
        }
        spin_unlock_irqrestore(&subpriv->spinlock, flags);
        return ret < 0 ? ret : insn->n;
}

/*
 * This function initializes an '8254' counter subdevice.
 */
static int
dio200_subdev_8254_init(struct comedi_device *dev, struct comedi_subdevice *s,
                        unsigned int offset)
{
        const struct dio200_layout *layout = dio200_dev_layout(dev);
        struct dio200_subdev_8254 *subpriv;
        unsigned int chan;

        subpriv = comedi_alloc_spriv(s, sizeof(*subpriv));
        if (!subpriv)
                return -ENOMEM;

        s->type = COMEDI_SUBD_COUNTER;
        s->subdev_flags = SDF_WRITABLE | SDF_READABLE;
        s->n_chan = 3;
        s->maxdata = 0xFFFF;
        s->insn_read = dio200_subdev_8254_read;
        s->insn_write = dio200_subdev_8254_write;
        s->insn_config = dio200_subdev_8254_config;

        spin_lock_init(&subpriv->spinlock);
        subpriv->ofs = offset;
        if (layout->has_clk_gat_sce) {
                /* Derive CLK_SCE and GAT_SCE register offsets from
                 * 8254 offset. */
                subpriv->clk_sce_ofs = DIO200_XCLK_SCE + (offset >> 3);
                subpriv->gat_sce_ofs = DIO200_XGAT_SCE + (offset >> 3);
                subpriv->which = (offset >> 2) & 1;
        }

        /* Initialize channels. */
        for (chan = 0; chan < 3; chan++) {
                dio200_subdev_8254_set_mode(dev, s, chan,
                                            I8254_MODE0 | I8254_BINARY);
                if (layout->has_clk_gat_sce) {
                        /* Gate source 0 is VCC (logic 1). */
                        dio200_subdev_8254_set_gate_src(dev, s, chan, 0);
                        /* Clock source 0 is the dedicated clock input. */
                        dio200_subdev_8254_set_clock_src(dev, s, chan, 0);
                }
        }

        return 0;
}

/*
 * This function sets I/O directions for an '8255' DIO subdevice.
 */
static void dio200_subdev_8255_set_dir(struct comedi_device *dev,
                                       struct comedi_subdevice *s)
{
        struct dio200_subdev_8255 *subpriv = s->private;
        int config;

        config = CR_CW;
        /* 1 in io_bits indicates output, 1 in config indicates input */
        if (!(s->io_bits & 0x0000ff))
                config |= CR_A_IO;
        if (!(s->io_bits & 0x00ff00))
                config |= CR_B_IO;
        if (!(s->io_bits & 0x0f0000))
                config |= CR_C_LO_IO;
        if (!(s->io_bits & 0xf00000))
                config |= CR_C_HI_IO;
        dio200_write8(dev, subpriv->ofs + 3, config);
}

/*
 * Handle 'insn_bits' for an '8255' DIO subdevice.
 */
static int dio200_subdev_8255_bits(struct comedi_device *dev,
                                   struct comedi_subdevice *s,
                                   struct comedi_insn *insn, unsigned int *data)
{
        struct dio200_subdev_8255 *subpriv = s->private;

        if (data[0]) {
                s->state &= ~data[0];
                s->state |= (data[0] & data[1]);
                if (data[0] & 0xff)
                        dio200_write8(dev, subpriv->ofs, s->state & 0xff);
                if (data[0] & 0xff00)
                        dio200_write8(dev, subpriv->ofs + 1,
                                      (s->state >> 8) & 0xff);
                if (data[0] & 0xff0000)
                        dio200_write8(dev, subpriv->ofs + 2,
                                      (s->state >> 16) & 0xff);
        }
        data[1] = dio200_read8(dev, subpriv->ofs);
        data[1] |= dio200_read8(dev, subpriv->ofs + 1) << 8;
        data[1] |= dio200_read8(dev, subpriv->ofs + 2) << 16;
        return 2;
}

/*
 * Handle 'insn_config' for an '8255' DIO subdevice.
 */
static int dio200_subdev_8255_config(struct comedi_device *dev,
                                     struct comedi_subdevice *s,
                                     struct comedi_insn *insn,
                                     unsigned int *data)
{
        unsigned int mask;
        unsigned int bits;

        mask = 1 << CR_CHAN(insn->chanspec);
        if (mask & 0x0000ff)
                bits = 0x0000ff;
        else if (mask & 0x00ff00)
                bits = 0x00ff00;
        else if (mask & 0x0f0000)
                bits = 0x0f0000;
        else
                bits = 0xf00000;
        switch (data[0]) {
        case INSN_CONFIG_DIO_INPUT:
                s->io_bits &= ~bits;
                break;
        case INSN_CONFIG_DIO_OUTPUT:
                s->io_bits |= bits;
                break;
        case INSN_CONFIG_DIO_QUERY:
                data[1] = (s->io_bits & bits) ? COMEDI_OUTPUT : COMEDI_INPUT;
                return insn->n;

                break;
        default:
                return -EINVAL;
        }
        dio200_subdev_8255_set_dir(dev, s);
        return 1;
}

/*
 * This function initializes an '8255' DIO subdevice.
 *
 * offset is the offset to the 8255 chip.
 */
static int dio200_subdev_8255_init(struct comedi_device *dev,
                                   struct comedi_subdevice *s,
                                   unsigned int offset)
{
        struct dio200_subdev_8255 *subpriv;

        subpriv = comedi_alloc_spriv(s, sizeof(*subpriv));
        if (!subpriv)
                return -ENOMEM;

        subpriv->ofs = offset;

        s->type = COMEDI_SUBD_DIO;
        s->subdev_flags = SDF_READABLE | SDF_WRITABLE;
        s->n_chan = 24;
        s->range_table = &range_digital;
        s->maxdata = 1;
        s->insn_bits = dio200_subdev_8255_bits;
        s->insn_config = dio200_subdev_8255_config;
        s->state = 0;
        s->io_bits = 0;
        dio200_subdev_8255_set_dir(dev, s);
        return 0;
}

/*
 * Handle 'insn_read' for a timer subdevice.
 */
static int dio200_subdev_timer_read(struct comedi_device *dev,
                                    struct comedi_subdevice *s,
                                    struct comedi_insn *insn,
                                    unsigned int *data)
{
        unsigned int n;

        for (n = 0; n < insn->n; n++)
                data[n] = dio200_read32(dev, DIO200_TS_COUNT);
        return n;
}

/*
 * Reset timer subdevice.
 */
static void dio200_subdev_timer_reset(struct comedi_device *dev,
                                      struct comedi_subdevice *s)
{
        unsigned int clock;

        clock = dio200_read32(dev, DIO200_TS_CONFIG) & TS_CONFIG_CLK_SRC_MASK;
        dio200_write32(dev, DIO200_TS_CONFIG, clock | TS_CONFIG_RESET);
        dio200_write32(dev, DIO200_TS_CONFIG, clock);
}

/*
 * Get timer subdevice clock source and period.
 */
static void dio200_subdev_timer_get_clock_src(struct comedi_device *dev,
                                              struct comedi_subdevice *s,
                                              unsigned int *src,
                                              unsigned int *period)
{
        unsigned int clk;

        clk = dio200_read32(dev, DIO200_TS_CONFIG) & TS_CONFIG_CLK_SRC_MASK;
        *src = clk;
        *period = (clk < ARRAY_SIZE(ts_clock_period)) ?
                  ts_clock_period[clk] : 0;
}

/*
 * Set timer subdevice clock source.
 */
static int dio200_subdev_timer_set_clock_src(struct comedi_device *dev,
                                             struct comedi_subdevice *s,
                                             unsigned int src)
{
        if (src > TS_CONFIG_MAX_CLK_SRC)
                return -EINVAL;
        dio200_write32(dev, DIO200_TS_CONFIG, src);
        return 0;
}

/*
 * Handle 'insn_config' for a timer subdevice.
 */
static int dio200_subdev_timer_config(struct comedi_device *dev,
                                      struct comedi_subdevice *s,
                                      struct comedi_insn *insn,
                                      unsigned int *data)
{
        int ret = 0;

        switch (data[0]) {
        case INSN_CONFIG_RESET:
                dio200_subdev_timer_reset(dev, s);
                break;
        case INSN_CONFIG_SET_CLOCK_SRC:
                ret = dio200_subdev_timer_set_clock_src(dev, s, data[1]);
                if (ret < 0)
                        ret = -EINVAL;
                break;
        case INSN_CONFIG_GET_CLOCK_SRC:
                dio200_subdev_timer_get_clock_src(dev, s, &data[1], &data[2]);
                break;
        default:
                ret = -EINVAL;
                break;
        }
        return ret < 0 ? ret : insn->n;
}

/*
 * This function initializes a timer subdevice.
 *
 * Uses the timestamp timer registers.  There is only one timestamp timer.
 */
static int dio200_subdev_timer_init(struct comedi_device *dev,
                                    struct comedi_subdevice *s)
{
        s->type = COMEDI_SUBD_TIMER;
        s->subdev_flags = SDF_READABLE | SDF_LSAMPL;
        s->n_chan = 1;
        s->maxdata = 0xFFFFFFFF;
        s->insn_read = dio200_subdev_timer_read;
        s->insn_config = dio200_subdev_timer_config;
        return 0;
}

void amplc_dio200_set_enhance(struct comedi_device *dev, unsigned char val)
{
        dio200_write8(dev, DIO200_ENHANCE, val);
}
EXPORT_SYMBOL_GPL(amplc_dio200_set_enhance);

int amplc_dio200_common_attach(struct comedi_device *dev, unsigned int irq,
                               unsigned long req_irq_flags)
{
        const struct dio200_board *thisboard = comedi_board(dev);
        struct dio200_private *devpriv = dev->private;
        const struct dio200_layout *layout = dio200_board_layout(thisboard);
        struct comedi_subdevice *s;
        int sdx;
        unsigned int n;
        int ret;

        devpriv->intr_sd = -1;

        ret = comedi_alloc_subdevices(dev, layout->n_subdevs);
        if (ret)
                return ret;

        for (n = 0; n < dev->n_subdevices; n++) {
                s = &dev->subdevices[n];
                switch (layout->sdtype[n]) {
                case sd_8254:
                        /* counter subdevice (8254) */
                        ret = dio200_subdev_8254_init(dev, s,
                                                      layout->sdinfo[n]);
                        if (ret < 0)
                                return ret;
                        break;
                case sd_8255:
                        /* digital i/o subdevice (8255) */
                        ret = dio200_subdev_8255_init(dev, s,
                                                      layout->sdinfo[n]);
                        if (ret < 0)
                                return ret;
                        break;
                case sd_intr:
                        /* 'INTERRUPT' subdevice */
                        if (irq) {
                                ret = dio200_subdev_intr_init(dev, s,
                                                              DIO200_INT_SCE,
                                                              layout->sdinfo[n]
                                                             );
                                if (ret < 0)
                                        return ret;
                                devpriv->intr_sd = n;
                        } else {
                                s->type = COMEDI_SUBD_UNUSED;
                        }
                        break;
                case sd_timer:
                        ret = dio200_subdev_timer_init(dev, s);
                        if (ret < 0)
                                return ret;
                        break;
                default:
                        s->type = COMEDI_SUBD_UNUSED;
                        break;
                }
        }
        sdx = devpriv->intr_sd;
        if (sdx >= 0 && sdx < dev->n_subdevices)
                dev->read_subdev = &dev->subdevices[sdx];
        if (irq) {
                if (request_irq(irq, dio200_interrupt, req_irq_flags,
                                dev->board_name, dev) >= 0) {
                        dev->irq = irq;
                } else {
                        dev_warn(dev->class_dev,
                                 "warning! irq %u unavailable!\n", irq);
                }
        }
        dev_info(dev->class_dev, "attached\n");
        return 0;
}
EXPORT_SYMBOL_GPL(amplc_dio200_common_attach);

void amplc_dio200_common_detach(struct comedi_device *dev)
{
        const struct dio200_board *thisboard = comedi_board(dev);
        struct dio200_private *devpriv = dev->private;

        if (!thisboard || !devpriv)
                return;
        if (dev->irq)
                free_irq(dev->irq, dev);
}
EXPORT_SYMBOL_GPL(amplc_dio200_common_detach);

static int __init amplc_dio200_common_init(void)
{
        return 0;
}
module_init(amplc_dio200_common_init);

static void __exit amplc_dio200_common_exit(void)
{
}
module_exit(amplc_dio200_common_exit);

MODULE_AUTHOR("Comedi http://www.comedi.org");
MODULE_DESCRIPTION("Comedi helper for amplc_dio200 and amplc_dio200_pci");
MODULE_LICENSE("GPL");