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/*
    comedi/drivers/ni_labpc.c
    Driver for National Instruments Lab-PC series boards and compatibles
    Copyright (C) 2001, 2002, 2003 Frank Mori Hess <fmhess@users.sourceforge.net>

    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.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

************************************************************************
*/
/*
Driver: ni_labpc
Description: National Instruments Lab-PC (& compatibles)
Author: Frank Mori Hess <fmhess@users.sourceforge.net>
Devices: [National Instruments] Lab-PC-1200 (labpc-1200),
  Lab-PC-1200AI (labpc-1200ai), Lab-PC+ (lab-pc+), PCI-1200 (ni_labpc)
Status: works

Tested with lab-pc-1200.  For the older Lab-PC+, not all input ranges
and analog references will work, the available ranges/arefs will
depend on how you have configured the jumpers on your board
(see your owner's manual).

Kernel-level ISA plug-and-play support for the lab-pc-1200
boards has not
yet been added to the driver, mainly due to the fact that
I don't know the device id numbers.  If you have one
of these boards,
please file a bug report at http://comedi.org/ 
so I can get the necessary information from you.

The 1200 series boards have onboard calibration dacs for correcting
analog input/output offsets and gains.  The proper settings for these
caldacs are stored on the board's eeprom.  To read the caldac values
from the eeprom and store them into a file that can be then be used by
comedilib, use the comedi_calibrate program.

Configuration options - ISA boards:
  [0] - I/O port base address
  [1] - IRQ (optional, required for timed or externally triggered conversions)
  [2] - DMA channel (optional)

Configuration options - PCI boards:
  [0] - bus (optional)
  [1] - slot (optional)

The Lab-pc+ has quirky chanlist requirements
when scanning multiple channels.  Multiple channel scan
sequence must start at highest channel, then decrement down to
channel 0.  The rest of the cards can scan down like lab-pc+ or scan
up from channel zero.  Chanlists consisting of all one channel
are also legal, and allow you to pace conversions in bursts.

*/

/*

NI manuals:
341309a (labpc-1200 register manual)
340914a (pci-1200)
320502b (lab-pc+)

*/

#undef LABPC_DEBUG
/* #define LABPC_DEBUG    enable debugging messages */

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

#include <linux/delay.h>
#include <asm/dma.h>

#include "8253.h"
#include "8255.h"
#include "mite.h"
#include "comedi_fc.h"
#include "ni_labpc.h"

#define DRV_NAME "ni_labpc"

/* size of io region used by board */
#define LABPC_SIZE           32
/* 2 MHz master clock */
#define LABPC_TIMER_BASE            500

/* Registers for the lab-pc+ */

/* write-only registers */
#define COMMAND1_REG	0x0
#define   ADC_GAIN_MASK	(0x7 << 4)
#define   ADC_CHAN_BITS(x)	((x) & 0x7)
/* enables multi channel scans */
#define   ADC_SCAN_EN_BIT	0x80
#define COMMAND2_REG	0x1
/* enable pretriggering (used in conjunction with SWTRIG) */
#define   PRETRIG_BIT	0x1
/* enable paced conversions on external trigger */
#define   HWTRIG_BIT	0x2
/* enable paced conversions */
#define   SWTRIG_BIT	0x4
/* use two cascaded counters for pacing */
#define   CASCADE_BIT	0x8
#define   DAC_PACED_BIT(channel)	(0x40 << ((channel) & 0x1))
#define COMMAND3_REG	0x2
/* enable dma transfers */
#define   DMA_EN_BIT	0x1
/* enable interrupts for 8255 */
#define   DIO_INTR_EN_BIT	0x2
/* enable dma terminal count interrupt */
#define   DMATC_INTR_EN_BIT	0x4
/* enable timer interrupt */
#define   TIMER_INTR_EN_BIT	0x8
/* enable error interrupt */
#define   ERR_INTR_EN_BIT	0x10
/* enable fifo not empty interrupt */
#define   ADC_FNE_INTR_EN_BIT	0x20
#define ADC_CONVERT_REG	0x3
#define DAC_LSB_REG(channel)	(0x4 + 2 * ((channel) & 0x1))
#define DAC_MSB_REG(channel)	(0x5 + 2 * ((channel) & 0x1))
#define ADC_CLEAR_REG	0x8
#define DMATC_CLEAR_REG	0xa
#define TIMER_CLEAR_REG	0xc
/* 1200 boards only */
#define COMMAND6_REG	0xe
/* select ground or common-mode reference */
#define   ADC_COMMON_BIT	0x1
/*  adc unipolar */
#define   ADC_UNIP_BIT	0x2
/*  dac unipolar */
#define   DAC_UNIP_BIT(channel)	(0x4 << ((channel) & 0x1))
/* enable fifo half full interrupt */
#define   ADC_FHF_INTR_EN_BIT	0x20
/* enable interrupt on end of hardware count */
#define   A1_INTR_EN_BIT	0x40
/* scan up from channel zero instead of down to zero */
#define   ADC_SCAN_UP_BIT 0x80
#define COMMAND4_REG	0xf
/* enables 'interval' scanning */
#define   INTERVAL_SCAN_EN_BIT	0x1
/* enables external signal on counter b1 output to trigger scan */
#define   EXT_SCAN_EN_BIT	0x2
/* chooses direction (output or input) for EXTCONV* line */
#define   EXT_CONVERT_OUT_BIT	0x4
/* chooses differential inputs for adc (in conjunction with board jumper) */
#define   ADC_DIFF_BIT	0x8
#define   EXT_CONVERT_DISABLE_BIT	0x10
/* 1200 boards only, calibration stuff */
#define COMMAND5_REG	0x1c
/* enable eeprom for write */
#define   EEPROM_WRITE_UNPROTECT_BIT	0x4
/* enable dithering */
#define   DITHER_EN_BIT	0x8
/* load calibration dac */
#define   CALDAC_LOAD_BIT	0x10
/* serial clock - rising edge writes, falling edge reads */
#define   SCLOCK_BIT	0x20
/* serial data bit for writing to eeprom or calibration dacs */
#define   SDATA_BIT	0x40
/* enable eeprom for read/write */
#define   EEPROM_EN_BIT	0x80
#define INTERVAL_COUNT_REG	0x1e
#define INTERVAL_LOAD_REG	0x1f
#define   INTERVAL_LOAD_BITS	0x1

/* read-only registers */
#define STATUS1_REG	0x0
/* data is available in fifo */
#define   DATA_AVAIL_BIT	0x1
/* overrun has occurred */
#define   OVERRUN_BIT	0x2
/* fifo overflow */
#define   OVERFLOW_BIT	0x4
/* timer interrupt has occurred */
#define   TIMER_BIT	0x8
/* dma terminal count has occurred */
#define   DMATC_BIT	0x10
/* external trigger has occurred */
#define   EXT_TRIG_BIT	0x40
/* 1200 boards only */
#define STATUS2_REG	0x1d
/* programmable eeprom serial output */
#define   EEPROM_OUT_BIT	0x1
/* counter A1 terminal count */
#define   A1_TC_BIT	0x2
/* fifo not half full */
#define   FNHF_BIT	0x4
#define ADC_FIFO_REG	0xa

#define DIO_BASE_REG	0x10
#define COUNTER_A_BASE_REG	0x14
#define COUNTER_A_CONTROL_REG	(COUNTER_A_BASE_REG + 0x3)
/* check modes put conversion pacer output in harmless state (a0 mode 2) */
#define   INIT_A0_BITS	0x14
/* put hardware conversion counter output in harmless state (a1 mode 0) */
#define   INIT_A1_BITS	0x70
#define COUNTER_B_BASE_REG	0x18

static int labpc_attach(struct comedi_device *dev, struct comedi_devconfig *it);
static int labpc_cancel(struct comedi_device *dev, struct comedi_subdevice *s);
static irqreturn_t labpc_interrupt(int irq, void *d);
static int labpc_drain_fifo(struct comedi_device *dev);
static void labpc_drain_dma(struct comedi_device *dev);
static void handle_isa_dma(struct comedi_device *dev);
static void labpc_drain_dregs(struct comedi_device *dev);
static int labpc_ai_cmdtest(struct comedi_device *dev,
			    struct comedi_subdevice *s, struct comedi_cmd *cmd);
static int labpc_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s);
static int labpc_ai_rinsn(struct comedi_device *dev, struct comedi_subdevice *s,
			  struct comedi_insn *insn, unsigned int *data);
static int labpc_ao_winsn(struct comedi_device *dev, struct comedi_subdevice *s,
			  struct comedi_insn *insn, unsigned int *data);
static int labpc_ao_rinsn(struct comedi_device *dev, struct comedi_subdevice *s,
			  struct comedi_insn *insn, unsigned int *data);
static int labpc_calib_read_insn(struct comedi_device *dev,
				 struct comedi_subdevice *s,
				 struct comedi_insn *insn, unsigned int *data);
static int labpc_calib_write_insn(struct comedi_device *dev,
				  struct comedi_subdevice *s,
				  struct comedi_insn *insn, unsigned int *data);
static int labpc_eeprom_read_insn(struct comedi_device *dev,
				  struct comedi_subdevice *s,
				  struct comedi_insn *insn, unsigned int *data);
static int labpc_eeprom_write_insn(struct comedi_device *dev,
				   struct comedi_subdevice *s,
				   struct comedi_insn *insn,
				   unsigned int *data);
static unsigned int labpc_suggest_transfer_size(struct comedi_cmd cmd);
static void labpc_adc_timing(struct comedi_device *dev, struct comedi_cmd *cmd);
#ifdef CONFIG_COMEDI_PCI
static int labpc_find_device(struct comedi_device *dev, int bus, int slot);
#endif
static int labpc_dio_mem_callback(int dir, int port, int data,
				  unsigned long arg);
static void labpc_serial_out(struct comedi_device *dev, unsigned int value,
			     unsigned int num_bits);
static unsigned int labpc_serial_in(struct comedi_device *dev);
static unsigned int labpc_eeprom_read(struct comedi_device *dev,
				      unsigned int address);
static unsigned int labpc_eeprom_read_status(struct comedi_device *dev);
static int labpc_eeprom_write(struct comedi_device *dev,
				       unsigned int address,
				       unsigned int value);
static void write_caldac(struct comedi_device *dev, unsigned int channel,
			 unsigned int value);

enum scan_mode {
	MODE_SINGLE_CHAN,
	MODE_SINGLE_CHAN_INTERVAL,
	MODE_MULT_CHAN_UP,
	MODE_MULT_CHAN_DOWN,
};

/* analog input ranges */
#define NUM_LABPC_PLUS_AI_RANGES 16
/* indicates unipolar ranges */
static const int labpc_plus_is_unipolar[NUM_LABPC_PLUS_AI_RANGES] = {
	0,
	0,
	0,
	0,
	0,
	0,
	0,
	0,
	1,
	1,
	1,
	1,
	1,
	1,
	1,
	1,
};

/* map range index to gain bits */
static const int labpc_plus_ai_gain_bits[NUM_LABPC_PLUS_AI_RANGES] = {
	0x00,
	0x10,
	0x20,
	0x30,
	0x40,
	0x50,
	0x60,
	0x70,
	0x00,
	0x10,
	0x20,
	0x30,
	0x40,
	0x50,
	0x60,
	0x70,
};

static const struct comedi_lrange range_labpc_plus_ai = {
	NUM_LABPC_PLUS_AI_RANGES,
	{
	 BIP_RANGE(5),
	 BIP_RANGE(4),
	 BIP_RANGE(2.5),
	 BIP_RANGE(1),
	 BIP_RANGE(0.5),
	 BIP_RANGE(0.25),
	 BIP_RANGE(0.1),
	 BIP_RANGE(0.05),
	 UNI_RANGE(10),
	 UNI_RANGE(8),
	 UNI_RANGE(5),
	 UNI_RANGE(2),
	 UNI_RANGE(1),
	 UNI_RANGE(0.5),
	 UNI_RANGE(0.2),
	 UNI_RANGE(0.1),
	 }
};

#define NUM_LABPC_1200_AI_RANGES 14
/* indicates unipolar ranges */
const int labpc_1200_is_unipolar[NUM_LABPC_1200_AI_RANGES] = {
	0,
	0,
	0,
	0,
	0,
	0,
	0,
	1,
	1,
	1,
	1,
	1,
	1,
	1,
};
EXPORT_SYMBOL_GPL(labpc_1200_is_unipolar);

/* map range index to gain bits */
const int labpc_1200_ai_gain_bits[NUM_LABPC_1200_AI_RANGES] = {
	0x00,
	0x20,
	0x30,
	0x40,
	0x50,
	0x60,
	0x70,
	0x00,
	0x20,
	0x30,
	0x40,
	0x50,
	0x60,
	0x70,
};
EXPORT_SYMBOL_GPL(labpc_1200_ai_gain_bits);

const struct comedi_lrange range_labpc_1200_ai = {
	NUM_LABPC_1200_AI_RANGES,
	{
	 BIP_RANGE(5),
	 BIP_RANGE(2.5),
	 BIP_RANGE(1),
	 BIP_RANGE(0.5),
	 BIP_RANGE(0.25),
	 BIP_RANGE(0.1),
	 BIP_RANGE(0.05),
	 UNI_RANGE(10),
	 UNI_RANGE(5),
	 UNI_RANGE(2),
	 UNI_RANGE(1),
	 UNI_RANGE(0.5),
	 UNI_RANGE(0.2),
	 UNI_RANGE(0.1),
	 }
};
EXPORT_SYMBOL_GPL(range_labpc_1200_ai);

/* analog output ranges */
#define AO_RANGE_IS_UNIPOLAR 0x1
static const struct comedi_lrange range_labpc_ao = {
	2,
	{
	 BIP_RANGE(5),
	 UNI_RANGE(10),
	 }
};

/* functions that do inb/outb and readb/writeb so we can use
 * function pointers to decide which to use */
static inline unsigned int labpc_inb(unsigned long address)
{
	return inb(address);
}

static inline void labpc_outb(unsigned int byte, unsigned long address)
{
	outb(byte, address);
}

static inline unsigned int labpc_readb(unsigned long address)
{
	return readb((void *)address);
}

static inline void labpc_writeb(unsigned int byte, unsigned long address)
{
	writeb(byte, (void *)address);
}

static const struct labpc_board_struct labpc_boards[] = {
	{
	 .name = "lab-pc-1200",
	 .ai_speed = 10000,
	 .bustype = isa_bustype,
	 .register_layout = labpc_1200_layout,
	 .has_ao = 1,
	 .ai_range_table = &range_labpc_1200_ai,
	 .ai_range_code = labpc_1200_ai_gain_bits,
	 .ai_range_is_unipolar = labpc_1200_is_unipolar,
	 .ai_scan_up = 1,
	 .memory_mapped_io = 0,
	 },
	{
	 .name = "lab-pc-1200ai",
	 .ai_speed = 10000,
	 .bustype = isa_bustype,
	 .register_layout = labpc_1200_layout,
	 .has_ao = 0,
	 .ai_range_table = &range_labpc_1200_ai,
	 .ai_range_code = labpc_1200_ai_gain_bits,
	 .ai_range_is_unipolar = labpc_1200_is_unipolar,
	 .ai_scan_up = 1,
	 .memory_mapped_io = 0,
	 },
	{
	 .name = "lab-pc+",
	 .ai_speed = 12000,
	 .bustype = isa_bustype,
	 .register_layout = labpc_plus_layout,
	 .has_ao = 1,
	 .ai_range_table = &range_labpc_plus_ai,
	 .ai_range_code = labpc_plus_ai_gain_bits,
	 .ai_range_is_unipolar = labpc_plus_is_unipolar,
	 .ai_scan_up = 0,
	 .memory_mapped_io = 0,
	 },
#ifdef CONFIG_COMEDI_PCI
	{
	 .name = "pci-1200",
	 .device_id = 0x161,
	 .ai_speed = 10000,
	 .bustype = pci_bustype,
	 .register_layout = labpc_1200_layout,
	 .has_ao = 1,
	 .ai_range_table = &range_labpc_1200_ai,
	 .ai_range_code = labpc_1200_ai_gain_bits,
	 .ai_range_is_unipolar = labpc_1200_is_unipolar,
	 .ai_scan_up = 1,
	 .memory_mapped_io = 1,
	 },
/* dummy entry so pci board works when comedi_config is passed driver name */
	{
	 .name = DRV_NAME,
	 .bustype = pci_bustype,
	 },
#endif
};

/*
 * Useful for shorthand access to the particular board structure
 */
#define thisboard ((struct labpc_board_struct *)dev->board_ptr)

/* size in bytes of dma buffer */
static const int dma_buffer_size = 0xff00;
/* 2 bytes per sample */
static const int sample_size = 2;

#define devpriv ((struct labpc_private *)dev->private)

static struct comedi_driver driver_labpc = {
	.driver_name = DRV_NAME,
	.module = THIS_MODULE,
	.attach = labpc_attach,
	.detach = labpc_common_detach,
	.num_names = ARRAY_SIZE(labpc_boards),
	.board_name = &labpc_boards[0].name,
	.offset = sizeof(struct labpc_board_struct),
};

#ifdef CONFIG_COMEDI_PCI
static DEFINE_PCI_DEVICE_TABLE(labpc_pci_table) = {
	{PCI_DEVICE(PCI_VENDOR_ID_NI, 0x161)},
	{0}
};

MODULE_DEVICE_TABLE(pci, labpc_pci_table);
#endif /* CONFIG_COMEDI_PCI */

static inline int labpc_counter_load(struct comedi_device *dev,
				     unsigned long base_address,
				     unsigned int counter_number,
				     unsigned int count, unsigned int mode)
{
	if (thisboard->memory_mapped_io)
		return i8254_mm_load((void *)base_address, 0, counter_number,
				     count, mode);
	else
		return i8254_load(base_address, 0, counter_number, count, mode);
}

int labpc_common_attach(struct comedi_device *dev, unsigned long iobase,
			unsigned int irq, unsigned int dma_chan)
{
	struct comedi_subdevice *s;
	int i;
	unsigned long dma_flags, isr_flags;
	short lsb, msb;

	printk(KERN_ERR "comedi%d: ni_labpc: %s, io 0x%lx", dev->minor,
								thisboard->name,
	       iobase);
	if (irq)
		printk(", irq %u", irq);
	if (dma_chan)
		printk(", dma %u", dma_chan);
	printk("\n");

	if (iobase == 0) {
		printk(KERN_ERR "io base address is zero!\n");
		return -EINVAL;
	}
	/*  request io regions for isa boards */
	if (thisboard->bustype == isa_bustype) {
		/* check if io addresses are available */
		if (!request_region(iobase, LABPC_SIZE,
				    driver_labpc.driver_name)) {
			printk(KERN_ERR "I/O port conflict\n");
			return -EIO;
		}
	}
	dev->iobase = iobase;

	if (thisboard->memory_mapped_io) {
		devpriv->read_byte = labpc_readb;
		devpriv->write_byte = labpc_writeb;
	} else {
		devpriv->read_byte = labpc_inb;
		devpriv->write_byte = labpc_outb;
	}
	/* initialize board's command registers */
	devpriv->write_byte(devpriv->command1_bits, dev->iobase + COMMAND1_REG);
	devpriv->write_byte(devpriv->command2_bits, dev->iobase + COMMAND2_REG);
	devpriv->write_byte(devpriv->command3_bits, dev->iobase + COMMAND3_REG);
	devpriv->write_byte(devpriv->command4_bits, dev->iobase + COMMAND4_REG);
	if (thisboard->register_layout == labpc_1200_layout) {
		devpriv->write_byte(devpriv->command5_bits,
				    dev->iobase + COMMAND5_REG);
		devpriv->write_byte(devpriv->command6_bits,
				    dev->iobase + COMMAND6_REG);
	}

	/* grab our IRQ */
	if (irq) {
		isr_flags = 0;
		if (thisboard->bustype == pci_bustype
		    || thisboard->bustype == pcmcia_bustype)
			isr_flags |= IRQF_SHARED;
		if (request_irq(irq, labpc_interrupt, isr_flags,
				driver_labpc.driver_name, dev)) {
			printk(KERN_ERR "unable to allocate irq %u\n", irq);
			return -EINVAL;
		}
	}
	dev->irq = irq;

	/* grab dma channel */
	if (dma_chan > 3) {
		printk(KERN_ERR " invalid dma channel %u\n", dma_chan);
		return -EINVAL;
	} else if (dma_chan) {
		/* allocate dma buffer */
		devpriv->dma_buffer =
		    kmalloc(dma_buffer_size, GFP_KERNEL | GFP_DMA);
		if (devpriv->dma_buffer == NULL) {
			printk(KERN_ERR " failed to allocate dma buffer\n");
			return -ENOMEM;
		}
		if (request_dma(dma_chan, driver_labpc.driver_name)) {
			printk(KERN_ERR " failed to allocate dma channel %u\n",
			       dma_chan);
			return -EINVAL;
		}
		devpriv->dma_chan = dma_chan;
		dma_flags = claim_dma_lock();
		disable_dma(devpriv->dma_chan);
		set_dma_mode(devpriv->dma_chan, DMA_MODE_READ);
		release_dma_lock(dma_flags);
	}

	dev->board_name = thisboard->name;

	if (alloc_subdevices(dev, 5) < 0)
		return -ENOMEM;

	/* analog input subdevice */
	s = dev->subdevices + 0;
	dev->read_subdev = s;
	s->type = COMEDI_SUBD_AI;
	s->subdev_flags =
	    SDF_READABLE | SDF_GROUND | SDF_COMMON | SDF_DIFF | SDF_CMD_READ;
	s->n_chan = 8;
	s->len_chanlist = 8;
	s->maxdata = (1 << 12) - 1;	/* 12 bit resolution */
	s->range_table = thisboard->ai_range_table;
	s->do_cmd = labpc_ai_cmd;
	s->do_cmdtest = labpc_ai_cmdtest;
	s->insn_read = labpc_ai_rinsn;
	s->cancel = labpc_cancel;

	/* analog output */
	s = dev->subdevices + 1;
	if (thisboard->has_ao) {
		/*
		 * Could provide command support, except it only has a
		 * one sample hardware buffer for analog output and no
		 * underrun flag.
		 */
		s->type = COMEDI_SUBD_AO;
		s->subdev_flags = SDF_READABLE | SDF_WRITABLE | SDF_GROUND;
		s->n_chan = NUM_AO_CHAN;
		s->maxdata = (1 << 12) - 1;	/*  12 bit resolution */
		s->range_table = &range_labpc_ao;
		s->insn_read = labpc_ao_rinsn;
		s->insn_write = labpc_ao_winsn;
		/* initialize analog outputs to a known value */
		for (i = 0; i < s->n_chan; i++) {
			devpriv->ao_value[i] = s->maxdata / 2;
			lsb = devpriv->ao_value[i] & 0xff;
			msb = (devpriv->ao_value[i] >> 8) & 0xff;
			devpriv->write_byte(lsb, dev->iobase + DAC_LSB_REG(i));
			devpriv->write_byte(msb, dev->iobase + DAC_MSB_REG(i));
		}
	} else {
		s->type = COMEDI_SUBD_UNUSED;
	}

	/* 8255 dio */
	s = dev->subdevices + 2;
	/*  if board uses io memory we have to give a custom callback
	 * function to the 8255 driver */
	if (thisboard->memory_mapped_io)
		subdev_8255_init(dev, s, labpc_dio_mem_callback,
				 (unsigned long)(dev->iobase + DIO_BASE_REG));
	else
		subdev_8255_init(dev, s, NULL, dev->iobase + DIO_BASE_REG);

	/*  calibration subdevices for boards that have one */
	s = dev->subdevices + 3;
	if (thisboard->register_layout == labpc_1200_layout) {
		s->type = COMEDI_SUBD_CALIB;
		s->subdev_flags = SDF_READABLE | SDF_WRITABLE | SDF_INTERNAL;
		s->n_chan = 16;
		s->maxdata = 0xff;
		s->insn_read = labpc_calib_read_insn;
		s->insn_write = labpc_calib_write_insn;

		for (i = 0; i < s->n_chan; i++)
			write_caldac(dev, i, s->maxdata / 2);
	} else
		s->type = COMEDI_SUBD_UNUSED;

	/* EEPROM */
	s = dev->subdevices + 4;
	if (thisboard->register_layout == labpc_1200_layout) {
		s->type = COMEDI_SUBD_MEMORY;
		s->subdev_flags = SDF_READABLE | SDF_WRITABLE | SDF_INTERNAL;
		s->n_chan = EEPROM_SIZE;
		s->maxdata = 0xff;
		s->insn_read = labpc_eeprom_read_insn;
		s->insn_write = labpc_eeprom_write_insn;

		for (i = 0; i < EEPROM_SIZE; i++)
			devpriv->eeprom_data[i] = labpc_eeprom_read(dev, i);
#ifdef LABPC_DEBUG
		printk(KERN_ERR " eeprom:");
		for (i = 0; i < EEPROM_SIZE; i++)
			printk(" %i:0x%x ", i, devpriv->eeprom_data[i]);
		printk("\n");
#endif
	} else
		s->type = COMEDI_SUBD_UNUSED;

	return 0;
}
EXPORT_SYMBOL_GPL(labpc_common_attach);

static int labpc_attach(struct comedi_device *dev, struct comedi_devconfig *it)
{
	unsigned long iobase = 0;
	unsigned int irq = 0;
	unsigned int dma_chan = 0;
#ifdef CONFIG_COMEDI_PCI
	int retval;
#endif

	/* allocate and initialize dev->private */
	if (alloc_private(dev, sizeof(struct labpc_private)) < 0)
		return -ENOMEM;

	/* get base address, irq etc. based on bustype */
	switch (thisboard->bustype) {
	case isa_bustype:
		iobase = it->options[0];
		irq = it->options[1];
		dma_chan = it->options[2];
		break;
	case pci_bustype:
#ifdef CONFIG_COMEDI_PCI
		retval = labpc_find_device(dev, it->options[0], it->options[1]);
		if (retval < 0)
			return retval;
		retval = mite_setup(devpriv->mite);
		if (retval < 0)
			return retval;
		iobase = (unsigned long)devpriv->mite->daq_io_addr;
		irq = mite_irq(devpriv->mite);
#else
		printk(KERN_ERR " this driver has not been built with PCI "
								"support.\n");
		return -EINVAL;
#endif
		break;
	case pcmcia_bustype:
		printk
		    (" this driver does not support pcmcia cards, use ni_labpc_cs.o\n");
		return -EINVAL;
		break;
	default:
		printk(KERN_ERR "bug! couldn't determine board type\n");
		return -EINVAL;
		break;
	}

	return labpc_common_attach(dev, iobase, irq, dma_chan);
}

/* adapted from ni_pcimio for finding mite based boards (pc-1200) */
#ifdef CONFIG_COMEDI_PCI
static int labpc_find_device(struct comedi_device *dev, int bus, int slot)
{
	struct mite_struct *mite;
	int i;
	for (mite = mite_devices; mite; mite = mite->next) {
		if (mite->used)
			continue;
/* if bus/slot are specified then make sure we have the right bus/slot */
		if (bus || slot) {
			if (bus != mite->pcidev->bus->number
			    || slot != PCI_SLOT(mite->pcidev->devfn))
				continue;
		}
		for (i = 0; i < driver_labpc.num_names; i++) {
			if (labpc_boards[i].bustype != pci_bustype)
				continue;
			if (mite_device_id(mite) == labpc_boards[i].device_id) {
				devpriv->mite = mite;
/* fixup board pointer, in case we were using the dummy "ni_labpc" entry */
				dev->board_ptr = &labpc_boards[i];
				return 0;
			}
		}
	}
	printk(KERN_ERR "no device found\n");
	mite_list_devices();
	return -EIO;
}
#endif

int labpc_common_detach(struct comedi_device *dev)
{
	printk(KERN_ERR "comedi%d: ni_labpc: detach\n", dev->minor);

	if (dev->subdevices)
		subdev_8255_cleanup(dev, dev->subdevices + 2);

	/* only free stuff if it has been allocated by _attach */
	kfree(devpriv->dma_buffer);
	if (devpriv->dma_chan)
		free_dma(devpriv->dma_chan);
	if (dev->irq)
		free_irq(dev->irq, dev);
	if (thisboard->bustype == isa_bustype && dev->iobase)
		release_region(dev->iobase, LABPC_SIZE);
#ifdef CONFIG_COMEDI_PCI
	if (devpriv->mite)
		mite_unsetup(devpriv->mite);
#endif

	return 0;
};
EXPORT_SYMBOL_GPL(labpc_common_detach);

static void labpc_clear_adc_fifo(const struct comedi_device *dev)
{
	devpriv->write_byte(0x1, dev->iobase + ADC_CLEAR_REG);
	devpriv->read_byte(dev->iobase + ADC_FIFO_REG);
	devpriv->read_byte(dev->iobase + ADC_FIFO_REG);
}

static int labpc_cancel(struct comedi_device *dev, struct comedi_subdevice *s)
{
	unsigned long flags;

	spin_lock_irqsave(&dev->spinlock, flags);
	devpriv->command2_bits &= ~SWTRIG_BIT & ~HWTRIG_BIT & ~PRETRIG_BIT;
	devpriv->write_byte(devpriv->command2_bits, dev->iobase + COMMAND2_REG);
	spin_unlock_irqrestore(&dev->spinlock, flags);

	devpriv->command3_bits = 0;
	devpriv->write_byte(devpriv->command3_bits, dev->iobase + COMMAND3_REG);

	return 0;
}

static enum scan_mode labpc_ai_scan_mode(const struct comedi_cmd *cmd)
{
	if (cmd->chanlist_len == 1)
		return MODE_SINGLE_CHAN;

	/* chanlist may be NULL during cmdtest. */
	if (cmd->chanlist == NULL)
		return MODE_MULT_CHAN_UP;

	if (CR_CHAN(cmd->chanlist[0]) == CR_CHAN(cmd->chanlist[1]))
		return MODE_SINGLE_CHAN_INTERVAL;

	if (CR_CHAN(cmd->chanlist[0]) < CR_CHAN(cmd->chanlist[1]))
		return MODE_MULT_CHAN_UP;

	if (CR_CHAN(cmd->chanlist[0]) > CR_CHAN(cmd->chanlist[1]))
		return MODE_MULT_CHAN_DOWN;

	printk(KERN_ERR "ni_labpc: bug! this should never happen\n");

	return 0;
}

static int labpc_ai_chanlist_invalid(const struct comedi_device *dev,
				     const struct comedi_cmd *cmd)
{
	int mode, channel, range, aref, i;

	if (cmd->chanlist == NULL)
		return 0;

	mode = labpc_ai_scan_mode(cmd);

	if (mode == MODE_SINGLE_CHAN)
		return 0;

	if (mode == MODE_SINGLE_CHAN_INTERVAL) {
		if (cmd->chanlist_len > 0xff) {
			comedi_error(dev,
				     "ni_labpc: chanlist too long for single channel interval mode\n");
			return 1;
		}
	}

	channel = CR_CHAN(cmd->chanlist[0]);
	range = CR_RANGE(cmd->chanlist[0]);
	aref = CR_AREF(cmd->chanlist[0]);

	for (i = 0; i < cmd->chanlist_len; i++) {

		switch (mode) {
		case MODE_SINGLE_CHAN_INTERVAL:
			if (CR_CHAN(cmd->chanlist[i]) != channel) {
				comedi_error(dev,
					     "channel scanning order specified in chanlist is not supported by hardware.\n");
				return 1;
			}
			break;
		case MODE_MULT_CHAN_UP:
			if (CR_CHAN(cmd->chanlist[i]) != i) {
				comedi_error(dev,
					     "channel scanning order specified in chanlist is not supported by hardware.\n");
				return 1;
			}
			break;
		case MODE_MULT_CHAN_DOWN:
			if (CR_CHAN(cmd->chanlist[i]) !=
			    cmd->chanlist_len - i - 1) {
				comedi_error(dev,
					     "channel scanning order specified in chanlist is not supported by hardware.\n");
				return 1;
			}
			break;
		default:
			printk(KERN_ERR "ni_labpc: bug! in chanlist check\n");
			return 1;
			break;
		}

		if (CR_RANGE(cmd->chanlist[i]) != range) {
			comedi_error(dev,
				     "entries in chanlist must all have the same range\n");
			return 1;
		}

		if (CR_AREF(cmd->chanlist[i]) != aref) {
			comedi_error(dev,
				     "entries in chanlist must all have the same reference\n");
			return 1;
		}
	}

	return 0;
}

static int labpc_use_continuous_mode(const struct comedi_cmd *cmd)
{
	if (labpc_ai_scan_mode(cmd) == MODE_SINGLE_CHAN)
		return 1;

	if (cmd->scan_begin_src == TRIG_FOLLOW)
		return 1;

	return 0;
}

static unsigned int labpc_ai_convert_period(const struct comedi_cmd *cmd)
{
	if (cmd->convert_src != TRIG_TIMER)
		return 0;

	if (labpc_ai_scan_mode(cmd) == MODE_SINGLE_CHAN &&
	    cmd->scan_begin_src == TRIG_TIMER)
		return cmd->scan_begin_arg;

	return cmd->convert_arg;
}

static void labpc_set_ai_convert_period(struct comedi_cmd *cmd, unsigned int ns)
{
	if (cmd->convert_src != TRIG_TIMER)
		return;

	if (labpc_ai_scan_mode(cmd) == MODE_SINGLE_CHAN &&
	    cmd->scan_begin_src == TRIG_TIMER) {
		cmd->scan_begin_arg = ns;
		if (cmd->convert_arg > cmd->scan_begin_arg)
			cmd->convert_arg = cmd->scan_begin_arg;
	} else
		cmd->convert_arg = ns;
}

static unsigned int labpc_ai_scan_period(const struct comedi_cmd *cmd)
{
	if (cmd->scan_begin_src != TRIG_TIMER)
		return 0;

	if (labpc_ai_scan_mode(cmd) == MODE_SINGLE_CHAN &&
	    cmd->convert_src == TRIG_TIMER)
		return 0;

	return cmd->scan_begin_arg;
}

static void labpc_set_ai_scan_period(struct comedi_cmd *cmd, unsigned int ns)
{
	if (cmd->scan_begin_src != TRIG_TIMER)
		return;

	if (labpc_ai_scan_mode(cmd) == MODE_SINGLE_CHAN &&
	    cmd->convert_src == TRIG_TIMER)
		return;

	cmd->scan_begin_arg = ns;
}

static int labpc_ai_cmdtest(struct comedi_device *dev,
			    struct comedi_subdevice *s, struct comedi_cmd *cmd)
{
	int err = 0;
	int tmp, tmp2;
	int stop_mask;

	/* step 1: make sure trigger sources are trivially valid */

	tmp = cmd->start_src;
	cmd->start_src &= TRIG_NOW | TRIG_EXT;
	if (!cmd->start_src || tmp != cmd->start_src)
		err++;

	tmp = cmd->scan_begin_src;
	cmd->scan_begin_src &= TRIG_TIMER | TRIG_FOLLOW | TRIG_EXT;
	if (!cmd->scan_begin_src || tmp != cmd->scan_begin_src)
		err++;

	tmp = cmd->convert_src;
	cmd->convert_src &= TRIG_TIMER | TRIG_EXT;
	if (!cmd->convert_src || tmp != cmd->convert_src)
		err++;

	tmp = cmd->scan_end_src;
	cmd->scan_end_src &= TRIG_COUNT;
	if (!cmd->scan_end_src || tmp != cmd->scan_end_src)
		err++;

	tmp = cmd->stop_src;
	stop_mask = TRIG_COUNT | TRIG_NONE;
	if (thisboard->register_layout == labpc_1200_layout)
		stop_mask |= TRIG_EXT;
	cmd->stop_src &= stop_mask;
	if (!cmd->stop_src || tmp != cmd->stop_src)
		err++;

	if (err)
		return 1;

	/* step 2: make sure trigger sources are unique and mutually compatible */

	if (cmd->start_src != TRIG_NOW && cmd->start_src != TRIG_EXT)
		err++;
	if (cmd->scan_begin_src != TRIG_TIMER &&
	    cmd->scan_begin_src != TRIG_FOLLOW &&
	    cmd->scan_begin_src != TRIG_EXT)
		err++;
	if (cmd->convert_src != TRIG_TIMER && cmd->convert_src != TRIG_EXT)
		err++;
	if (cmd->stop_src != TRIG_COUNT &&
	    cmd->stop_src != TRIG_EXT && cmd->stop_src != TRIG_NONE)
		err++;

	/* can't have external stop and start triggers at once */
	if (cmd->start_src == TRIG_EXT && cmd->stop_src == TRIG_EXT)
		err++;

	if (err)
		return 2;

	/* step 3: make sure arguments are trivially compatible */

	if (cmd->start_arg == TRIG_NOW && cmd->start_arg != 0) {
		cmd->start_arg = 0;
		err++;
	}

	if (!cmd->chanlist_len)
		err++;

	if (cmd->scan_end_arg != cmd->chanlist_len) {
		cmd->scan_end_arg = cmd->chanlist_len;
		err++;
	}

	if (cmd->convert_src == TRIG_TIMER) {
		if (cmd->convert_arg < thisboard->ai_speed) {
			cmd->convert_arg = thisboard->ai_speed;
			err++;
		}
	}
	/* make sure scan timing is not too fast */
	if (cmd->scan_begin_src == TRIG_TIMER) {
		if (cmd->convert_src == TRIG_TIMER &&
		    cmd->scan_begin_arg <
		    cmd->convert_arg * cmd->chanlist_len) {
			cmd->scan_begin_arg =
			    cmd->convert_arg * cmd->chanlist_len;
			err++;
		}
		if (cmd->scan_begin_arg <
		    thisboard->ai_speed * cmd->chanlist_len) {
			cmd->scan_begin_arg =
			    thisboard->ai_speed * cmd->chanlist_len;
			err++;
		}
	}
	/* stop source */
	switch (cmd->stop_src) {
	case TRIG_COUNT:
		if (!cmd->stop_arg) {
			cmd->stop_arg = 1;
			err++;
		}
		break;
	case TRIG_NONE:
		if (cmd->stop_arg != 0) {
			cmd->stop_arg = 0;
			err++;
		}
		break;
		/*
		 * TRIG_EXT doesn't care since it doesn't
		 * trigger off a numbered channel
		 */
	default:
		break;
	}

	if (err)
		return 3;

	/* step 4: fix up any arguments */

	tmp = cmd->convert_arg;
	tmp2 = cmd->scan_begin_arg;
	labpc_adc_timing(dev, cmd);
	if (tmp != cmd->convert_arg || tmp2 != cmd->scan_begin_arg)
		err++;

	if (err)
		return 4;

	if (labpc_ai_chanlist_invalid(dev, cmd))
		return 5;

	return 0;
}

static int labpc_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
{
	int channel, range, aref;
	unsigned long irq_flags;
	int ret;
	struct comedi_async *async = s->async;
	struct comedi_cmd *cmd = &async->cmd;
	enum transfer_type xfer;
	unsigned long flags;

	if (!dev->irq) {
		comedi_error(dev, "no irq assigned, cannot perform command");
		return -1;
	}

	range = CR_RANGE(cmd->chanlist[0]);
	aref = CR_AREF(cmd->chanlist[0]);

	/* make sure board is disabled before setting up acquisition */
	spin_lock_irqsave(&dev->spinlock, flags);
	devpriv->command2_bits &= ~SWTRIG_BIT & ~HWTRIG_BIT & ~PRETRIG_BIT;
	devpriv->write_byte(devpriv->command2_bits, dev->iobase + COMMAND2_REG);
	spin_unlock_irqrestore(&dev->spinlock, flags);

	devpriv->command3_bits = 0;
	devpriv->write_byte(devpriv->command3_bits, dev->iobase + COMMAND3_REG);

	/*  initialize software conversion count */
	if (cmd->stop_src == TRIG_COUNT)
		devpriv->count = cmd->stop_arg * cmd->chanlist_len;

	/*  setup hardware conversion counter */
	if (cmd->stop_src == TRIG_EXT) {
		/*
		 * load counter a1 with count of 3
		 * (pc+ manual says this is minimum allowed) using mode 0
		 */
		ret = labpc_counter_load(dev, dev->iobase + COUNTER_A_BASE_REG,
					 1, 3, 0);
		if (ret < 0) {
			comedi_error(dev, "error loading counter a1");
			return -1;
		}
	} else			/*
				 * otherwise, just put a1 in mode 0
				 * with no count to set its output low
				 */
		devpriv->write_byte(INIT_A1_BITS,
				    dev->iobase + COUNTER_A_CONTROL_REG);

	/*  figure out what method we will use to transfer data */
	if (devpriv->dma_chan &&	/*  need a dma channel allocated */
		/*
		 * dma unsafe at RT priority,
		 * and too much setup time for TRIG_WAKE_EOS for
		 */
	    (cmd->flags & (TRIG_WAKE_EOS | TRIG_RT)) == 0 &&
	    /*  only available on the isa boards */
	    thisboard->bustype == isa_bustype) {
		xfer = isa_dma_transfer;
		/* pc-plus has no fifo-half full interrupt */
	} else if (thisboard->register_layout == labpc_1200_layout &&
		   /*  wake-end-of-scan should interrupt on fifo not empty */
		   (cmd->flags & TRIG_WAKE_EOS) == 0 &&
		   /*  make sure we are taking more than just a few points */
		   (cmd->stop_src != TRIG_COUNT || devpriv->count > 256)) {
		xfer = fifo_half_full_transfer;
	} else
		xfer = fifo_not_empty_transfer;
	devpriv->current_transfer = xfer;

	/*  setup command6 register for 1200 boards */
	if (thisboard->register_layout == labpc_1200_layout) {
		/*  reference inputs to ground or common? */
		if (aref != AREF_GROUND)
			devpriv->command6_bits |= ADC_COMMON_BIT;
		else
			devpriv->command6_bits &= ~ADC_COMMON_BIT;
		/*  bipolar or unipolar range? */
		if (thisboard->ai_range_is_unipolar[range])
			devpriv->command6_bits |= ADC_UNIP_BIT;
		else
			devpriv->command6_bits &= ~ADC_UNIP_BIT;
		/*  interrupt on fifo half full? */
		if (xfer == fifo_half_full_transfer)
			devpriv->command6_bits |= ADC_FHF_INTR_EN_BIT;
		else
			devpriv->command6_bits &= ~ADC_FHF_INTR_EN_BIT;
		/*  enable interrupt on counter a1 terminal count? */
		if (cmd->stop_src == TRIG_EXT)
			devpriv->command6_bits |= A1_INTR_EN_BIT;
		else
			devpriv->command6_bits &= ~A1_INTR_EN_BIT;
		/*  are we scanning up or down through channels? */
		if (labpc_ai_scan_mode(cmd) == MODE_MULT_CHAN_UP)
			devpriv->command6_bits |= ADC_SCAN_UP_BIT;
		else
			devpriv->command6_bits &= ~ADC_SCAN_UP_BIT;
		/*  write to register */
		devpriv->write_byte(devpriv->command6_bits,
				    dev->iobase + COMMAND6_REG);
	}

	/* setup channel list, etc (command1 register) */
	devpriv->command1_bits = 0;
	if (labpc_ai_scan_mode(cmd) == MODE_MULT_CHAN_UP)
		channel = CR_CHAN(cmd->chanlist[cmd->chanlist_len - 1]);
	else
		channel = CR_CHAN(cmd->chanlist[0]);
	/* munge channel bits for differential / scan disabled mode */
	if ((labpc_ai_scan_mode(cmd) == MODE_SINGLE_CHAN ||
	     labpc_ai_scan_mode(cmd) == MODE_SINGLE_CHAN_INTERVAL) &&
	    aref == AREF_DIFF)
		channel *= 2;
	devpriv->command1_bits |= ADC_CHAN_BITS(channel);
	devpriv->command1_bits |= thisboard->ai_range_code[range];
	devpriv->write_byte(devpriv->command1_bits, dev->iobase + COMMAND1_REG);
	/* manual says to set scan enable bit on second pass */
	if (labpc_ai_scan_mode(cmd) == MODE_MULT_CHAN_UP ||
	    labpc_ai_scan_mode(cmd) == MODE_MULT_CHAN_DOWN) {
		devpriv->command1_bits |= ADC_SCAN_EN_BIT;
		/* need a brief delay before enabling scan, or scan
		 * list will get screwed when you switch
		 * between scan up to scan down mode - dunno why */
		udelay(1);
		devpriv->write_byte(devpriv->command1_bits,
				    dev->iobase + COMMAND1_REG);
	}
	/*  setup any external triggering/pacing (command4 register) */
	devpriv->command4_bits = 0;
	if (cmd->convert_src != TRIG_EXT)
		devpriv->command4_bits |= EXT_CONVERT_DISABLE_BIT;
	/* XXX should discard first scan when using interval scanning
	 * since manual says it is not synced with scan clock */
	if (labpc_use_continuous_mode(cmd) == 0) {
		devpriv->command4_bits |= INTERVAL_SCAN_EN_BIT;
		if (cmd->scan_begin_src == TRIG_EXT)
			devpriv->command4_bits |= EXT_SCAN_EN_BIT;
	}
	/*  single-ended/differential */
	if (aref == AREF_DIFF)
		devpriv->command4_bits |= ADC_DIFF_BIT;
	devpriv->write_byte(devpriv->command4_bits, dev->iobase + COMMAND4_REG);

	devpriv->write_byte(cmd->chanlist_len,
			    dev->iobase + INTERVAL_COUNT_REG);
	/*  load count */
	devpriv->write_byte(INTERVAL_LOAD_BITS,
			    dev->iobase + INTERVAL_LOAD_REG);

	if (cmd->convert_src == TRIG_TIMER || cmd->scan_begin_src == TRIG_TIMER) {
		/*  set up pacing */
		labpc_adc_timing(dev, cmd);
		/*  load counter b0 in mode 3 */
		ret = labpc_counter_load(dev, dev->iobase + COUNTER_B_BASE_REG,
					 0, devpriv->divisor_b0, 3);
		if (ret < 0) {
			comedi_error(dev, "error loading counter b0");
			return -1;
		}
	}
	/*  set up conversion pacing */
	if (labpc_ai_convert_period(cmd)) {
		/*  load counter a0 in mode 2 */
		ret = labpc_counter_load(dev, dev->iobase + COUNTER_A_BASE_REG,
					 0, devpriv->divisor_a0, 2);
		if (ret < 0) {
			comedi_error(dev, "error loading counter a0");
			return -1;
		}
	} else
		devpriv->write_byte(INIT_A0_BITS,
				    dev->iobase + COUNTER_A_CONTROL_REG);

	/*  set up scan pacing */
	if (labpc_ai_scan_period(cmd)) {
		/*  load counter b1 in mode 2 */
		ret = labpc_counter_load(dev, dev->iobase + COUNTER_B_BASE_REG,
					 1, devpriv->divisor_b1, 2);
		if (ret < 0) {
			comedi_error(dev, "error loading counter b1");
			return -1;
		}
	}

	labpc_clear_adc_fifo(dev);

	/*  set up dma transfer */
	if (xfer == isa_dma_transfer) {
		irq_flags = claim_dma_lock();
		disable_dma(devpriv->dma_chan);
		/* clear flip-flop to make sure 2-byte registers for
		 * count and address get set correctly */
		clear_dma_ff(devpriv->dma_chan);
		set_dma_addr(devpriv->dma_chan,
			     virt_to_bus(devpriv->dma_buffer));
		/*  set appropriate size of transfer */
		devpriv->dma_transfer_size = labpc_suggest_transfer_size(*cmd);
		if (cmd->stop_src == TRIG_COUNT &&
		    devpriv->count * sample_size < devpriv->dma_transfer_size) {
			devpriv->dma_transfer_size =
			    devpriv->count * sample_size;
		}
		set_dma_count(devpriv->dma_chan, devpriv->dma_transfer_size);
		enable_dma(devpriv->dma_chan);
		release_dma_lock(irq_flags);
		/*  enable board's dma */
		devpriv->command3_bits |= DMA_EN_BIT | DMATC_INTR_EN_BIT;
	} else
		devpriv->command3_bits &= ~DMA_EN_BIT & ~DMATC_INTR_EN_BIT;

	/*  enable error interrupts */
	devpriv->command3_bits |= ERR_INTR_EN_BIT;
	/*  enable fifo not empty interrupt? */
	if (xfer == fifo_not_empty_transfer)
		devpriv->command3_bits |= ADC_FNE_INTR_EN_BIT;
	else
		devpriv->command3_bits &= ~ADC_FNE_INTR_EN_BIT;
	devpriv->write_byte(devpriv->command3_bits, dev->iobase + COMMAND3_REG);

	/*  startup acquisition */

	/*  command2 reg */
	/*  use 2 cascaded counters for pacing */
	spin_lock_irqsave(&dev->spinlock, flags);
	devpriv->command2_bits |= CASCADE_BIT;
	switch (cmd->start_src) {
	case TRIG_EXT:
		devpriv->command2_bits |= HWTRIG_BIT;
		devpriv->command2_bits &= ~PRETRIG_BIT & ~SWTRIG_BIT;
		break;
	case TRIG_NOW:
		devpriv->command2_bits |= SWTRIG_BIT;
		devpriv->command2_bits &= ~PRETRIG_BIT & ~HWTRIG_BIT;
		break;
	default:
		comedi_error(dev, "bug with start_src");
		return -1;
		break;
	}
	switch (cmd->stop_src) {
	case TRIG_EXT:
		devpriv->command2_bits |= HWTRIG_BIT | PRETRIG_BIT;
		break;
	case TRIG_COUNT:
	case TRIG_NONE:
		break;
	default:
		comedi_error(dev, "bug with stop_src");
		return -1;
	}
	devpriv->write_byte(devpriv->command2_bits, dev->iobase + COMMAND2_REG);
	spin_unlock_irqrestore(&dev->spinlock, flags);

	return 0;
}

/* interrupt service routine */
static irqreturn_t labpc_interrupt(int irq, void *d)
{
	struct comedi_device *dev = d;
	struct comedi_subdevice *s = dev->read_subdev;
	struct comedi_async *async;
	struct comedi_cmd *cmd;

	if (dev->attached == 0) {
		comedi_error(dev, "premature interrupt");
		return IRQ_HANDLED;
	}

	async = s->async;
	cmd = &async->cmd;
	async->events = 0;

	/* read board status */
	devpriv->status1_bits = devpriv->read_byte(dev->iobase + STATUS1_REG);
	if (thisboard->register_layout == labpc_1200_layout)
		devpriv->status2_bits =
		    devpriv->read_byte(dev->iobase + STATUS2_REG);

	if ((devpriv->status1_bits & (DMATC_BIT | TIMER_BIT | OVERFLOW_BIT |
				      OVERRUN_BIT | DATA_AVAIL_BIT)) == 0
	    && (devpriv->status2_bits & A1_TC_BIT) == 0
	    && (devpriv->status2_bits & FNHF_BIT)) {
		return IRQ_NONE;
	}

	if (devpriv->status1_bits & OVERRUN_BIT) {
		/* clear error interrupt */
		devpriv->write_byte(0x1, dev->iobase + ADC_CLEAR_REG);
		async->events |= COMEDI_CB_ERROR | COMEDI_CB_EOA;
		comedi_event(dev, s);
		comedi_error(dev, "overrun");
		return IRQ_HANDLED;
	}

	if (devpriv->current_transfer == isa_dma_transfer) {
		/*
		 * if a dma terminal count of external stop trigger
		 * has occurred
		 */
		if (devpriv->status1_bits & DMATC_BIT ||
		    (thisboard->register_layout == labpc_1200_layout
		     && devpriv->status2_bits & A1_TC_BIT)) {
			handle_isa_dma(dev);
		}
	} else
		labpc_drain_fifo(dev);

	if (devpriv->status1_bits & TIMER_BIT) {
		comedi_error(dev, "handled timer interrupt?");
		/*  clear it */
		devpriv->write_byte(0x1, dev->iobase + TIMER_CLEAR_REG);
	}

	if (devpriv->status1_bits & OVERFLOW_BIT) {
		/*  clear error interrupt */
		devpriv->write_byte(0x1, dev->iobase + ADC_CLEAR_REG);
		async->events |= COMEDI_CB_ERROR | COMEDI_CB_EOA;
		comedi_event(dev, s);
		comedi_error(dev, "overflow");
		return IRQ_HANDLED;
	}
	/*  handle external stop trigger */
	if (cmd->stop_src == TRIG_EXT) {
		if (devpriv->status2_bits & A1_TC_BIT) {
			labpc_drain_dregs(dev);
			labpc_cancel(dev, s);
			async->events |= COMEDI_CB_EOA;
		}
	}

	/* TRIG_COUNT end of acquisition */
	if (cmd->stop_src == TRIG_COUNT) {
		if (devpriv->count == 0) {
			labpc_cancel(dev, s);
			async->events |= COMEDI_CB_EOA;
		}
	}

	comedi_event(dev, s);
	return IRQ_HANDLED;
}

/* read all available samples from ai fifo */
static int labpc_drain_fifo(struct comedi_device *dev)
{
	unsigned int lsb, msb;
	short data;
	struct comedi_async *async = dev->read_subdev->async;
	const int timeout = 10000;
	unsigned int i;

	devpriv->status1_bits = devpriv->read_byte(dev->iobase + STATUS1_REG);

	for (i = 0; (devpriv->status1_bits & DATA_AVAIL_BIT) && i < timeout;
	     i++) {
		/*  quit if we have all the data we want */
		if (async->cmd.stop_src == TRIG_COUNT) {
			if (devpriv->count == 0)
				break;
			devpriv->count--;
		}
		lsb = devpriv->read_byte(dev->iobase + ADC_FIFO_REG);
		msb = devpriv->read_byte(dev->iobase + ADC_FIFO_REG);
		data = (msb << 8) | lsb;
		cfc_write_to_buffer(dev->read_subdev, data);
		devpriv->status1_bits =
		    devpriv->read_byte(dev->iobase + STATUS1_REG);
	}
	if (i == timeout) {
		comedi_error(dev, "ai timeout, fifo never empties");
		async->events |= COMEDI_CB_ERROR | COMEDI_CB_EOA;
		return -1;
	}

	return 0;
}

static void labpc_drain_dma(struct comedi_device *dev)
{
	struct comedi_subdevice *s = dev->read_subdev;
	struct comedi_async *async = s->async;
	int status;
	unsigned long flags;
	unsigned int max_points, num_points, residue, leftover;
	int i;

	status = devpriv->status1_bits;

	flags = claim_dma_lock();
	disable_dma(devpriv->dma_chan);
	/* clear flip-flop to make sure 2-byte registers for
	 * count and address get set correctly */
	clear_dma_ff(devpriv->dma_chan);

	/*  figure out how many points to read */
	max_points = devpriv->dma_transfer_size / sample_size;
	/* residue is the number of points left to be done on the dma
	 * transfer.  It should always be zero at this point unless
	 * the stop_src is set to external triggering.
	 */
	residue = get_dma_residue(devpriv->dma_chan) / sample_size;
	num_points = max_points - residue;
	if (devpriv->count < num_points && async->cmd.stop_src == TRIG_COUNT)
		num_points = devpriv->count;

	/*  figure out how many points will be stored next time */
	leftover = 0;
	if (async->cmd.stop_src != TRIG_COUNT) {
		leftover = devpriv->dma_transfer_size / sample_size;
	} else if (devpriv->count > num_points) {
		leftover = devpriv->count - num_points;
		if (leftover > max_points)
			leftover = max_points;
	}

	/* write data to comedi buffer */
	for (i = 0; i < num_points; i++)
		cfc_write_to_buffer(s, devpriv->dma_buffer[i]);

	if (async->cmd.stop_src == TRIG_COUNT)
		devpriv->count -= num_points;

	/*  set address and count for next transfer */
	set_dma_addr(devpriv->dma_chan, virt_to_bus(devpriv->dma_buffer));
	set_dma_count(devpriv->dma_chan, leftover * sample_size);
	release_dma_lock(flags);

	async->events |= COMEDI_CB_BLOCK;
}

static void handle_isa_dma(struct comedi_device *dev)
{
	labpc_drain_dma(dev);

	enable_dma(devpriv->dma_chan);

	/*  clear dma tc interrupt */
	devpriv->write_byte(0x1, dev->iobase + DMATC_CLEAR_REG);
}

/* makes sure all data acquired by board is transferred to comedi (used
 * when acquisition is terminated by stop_src == TRIG_EXT). */
static void labpc_drain_dregs(struct comedi_device *dev)
{
	if (devpriv->current_transfer == isa_dma_transfer)
		labpc_drain_dma(dev);

	labpc_drain_fifo(dev);
}

static int labpc_ai_rinsn(struct comedi_device *dev, struct comedi_subdevice *s,
			  struct comedi_insn *insn, unsigned int *data)
{
	int i, n;
	int chan, range;
	int lsb, msb;
	int timeout = 1000;
	unsigned long flags;

	/*  disable timed conversions */
	spin_lock_irqsave(&dev->spinlock, flags);
	devpriv->command2_bits &= ~SWTRIG_BIT & ~HWTRIG_BIT & ~PRETRIG_BIT;
	devpriv->write_byte(devpriv->command2_bits, dev->iobase + COMMAND2_REG);
	spin_unlock_irqrestore(&dev->spinlock, flags);

	/*  disable interrupt generation and dma */
	devpriv->command3_bits = 0;
	devpriv->write_byte(devpriv->command3_bits, dev->iobase + COMMAND3_REG);

	/* set gain and channel */
	devpriv->command1_bits = 0;
	chan = CR_CHAN(insn->chanspec);
	range = CR_RANGE(insn->chanspec);
	devpriv->command1_bits |= thisboard->ai_range_code[range];
	/* munge channel bits for differential/scan disabled mode */
	if (CR_AREF(insn->chanspec) == AREF_DIFF)
		chan *= 2;
	devpriv->command1_bits |= ADC_CHAN_BITS(chan);
	devpriv->write_byte(devpriv->command1_bits, dev->iobase + COMMAND1_REG);

	/* setup command6 register for 1200 boards */
	if (thisboard->register_layout == labpc_1200_layout) {
		/*  reference inputs to ground or common? */
		if (CR_AREF(insn->chanspec) != AREF_GROUND)
			devpriv->command6_bits |= ADC_COMMON_BIT;
		else
			devpriv->command6_bits &= ~ADC_COMMON_BIT;
		/* bipolar or unipolar range? */
		if (thisboard->ai_range_is_unipolar[range])
			devpriv->command6_bits |= ADC_UNIP_BIT;
		else
			devpriv->command6_bits &= ~ADC_UNIP_BIT;
		/* don't interrupt on fifo half full */
		devpriv->command6_bits &= ~ADC_FHF_INTR_EN_BIT;
		/* don't enable interrupt on counter a1 terminal count? */
		devpriv->command6_bits &= ~A1_INTR_EN_BIT;
		/* write to register */
		devpriv->write_byte(devpriv->command6_bits,
				    dev->iobase + COMMAND6_REG);
	}
	/* setup command4 register */
	devpriv->command4_bits = 0;
	devpriv->command4_bits |= EXT_CONVERT_DISABLE_BIT;
	/* single-ended/differential */
	if (CR_AREF(insn->chanspec) == AREF_DIFF)
		devpriv->command4_bits |= ADC_DIFF_BIT;
	devpriv->write_byte(devpriv->command4_bits, dev->iobase + COMMAND4_REG);

	/*
	 * initialize pacer counter output to make sure it doesn't
	 * cause any problems
	 */
	devpriv->write_byte(INIT_A0_BITS, dev->iobase + COUNTER_A_CONTROL_REG);

	labpc_clear_adc_fifo(dev);

	for (n = 0; n < insn->n; n++) {
		/* trigger conversion */
		devpriv->write_byte(0x1, dev->iobase + ADC_CONVERT_REG);

		for (i = 0; i < timeout; i++) {
			if (devpriv->read_byte(dev->iobase +
					       STATUS1_REG) & DATA_AVAIL_BIT)
				break;
			udelay(1);
		}
		if (i == timeout) {
			comedi_error(dev, "timeout");
			return -ETIME;
		}
		lsb = devpriv->read_byte(dev->iobase + ADC_FIFO_REG);
		msb = devpriv->read_byte(dev->iobase + ADC_FIFO_REG);
		data[n] = (msb << 8) | lsb;
	}

	return n;
}

/* analog output insn */
static int labpc_ao_winsn(struct comedi_device *dev, struct comedi_subdevice *s,
			  struct comedi_insn *insn, unsigned int *data)
{
	int channel, range;
	unsigned long flags;
	int lsb, msb;

	channel = CR_CHAN(insn->chanspec);

	/* turn off pacing of analog output channel */
	/* note: hardware bug in daqcard-1200 means pacing cannot
	 * be independently enabled/disabled for its the two channels */
	spin_lock_irqsave(&dev->spinlock, flags);
	devpriv->command2_bits &= ~DAC_PACED_BIT(channel);
	devpriv->write_byte(devpriv->command2_bits, dev->iobase + COMMAND2_REG);
	spin_unlock_irqrestore(&dev->spinlock, flags);

	/* set range */
	if (thisboard->register_layout == labpc_1200_layout) {
		range = CR_RANGE(insn->chanspec);
		if (range & AO_RANGE_IS_UNIPOLAR)
			devpriv->command6_bits |= DAC_UNIP_BIT(channel);
		else
			devpriv->command6_bits &= ~DAC_UNIP_BIT(channel);
		/*  write to register */
		devpriv->write_byte(devpriv->command6_bits,
				    dev->iobase + COMMAND6_REG);
	}
	/* send data */
	lsb = data[0] & 0xff;
	msb = (data[0] >> 8) & 0xff;
	devpriv->write_byte(lsb, dev->iobase + DAC_LSB_REG(channel));
	devpriv->write_byte(msb, dev->iobase + DAC_MSB_REG(channel));

	/* remember value for readback */
	devpriv->ao_value[channel] = data[0];

	return 1;
}

/* analog output readback insn */
static int labpc_ao_rinsn(struct comedi_device *dev, struct comedi_subdevice *s,
			  struct comedi_insn *insn, unsigned int *data)
{
	data[0] = devpriv->ao_value[CR_CHAN(insn->chanspec)];

	return 1;
}

static int labpc_calib_read_insn(struct comedi_device *dev,
				 struct comedi_subdevice *s,
				 struct comedi_insn *insn, unsigned int *data)
{
	data[0] = devpriv->caldac[CR_CHAN(insn->chanspec)];

	return 1;
}

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

	write_caldac(dev, channel, data[0]);
	return 1;
}

static int labpc_eeprom_read_insn(struct comedi_device *dev,
				  struct comedi_subdevice *s,
				  struct comedi_insn *insn, unsigned int *data)
{
	data[0] = devpriv->eeprom_data[CR_CHAN(insn->chanspec)];

	return 1;
}

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

	/*  only allow writes to user area of eeprom */
	if (channel < 16 || channel > 127) {
		printk
		    ("eeprom writes are only allowed to channels 16 through 127 (the pointer and user areas)");
		return -EINVAL;
	}

	ret = labpc_eeprom_write(dev, channel, data[0]);
	if (ret < 0)
		return ret;

	return 1;
}

/* utility function that suggests a dma transfer size in bytes */
static unsigned int labpc_suggest_transfer_size(struct comedi_cmd cmd)
{
	unsigned int size;
	unsigned int freq;

	if (cmd.convert_src == TRIG_TIMER)
		freq = 1000000000 / cmd.convert_arg;
	/* return some default value */
	else
		freq = 0xffffffff;

	/* make buffer fill in no more than 1/3 second */
	size = (freq / 3) * sample_size;

	/* set a minimum and maximum size allowed */
	if (size > dma_buffer_size)
		size = dma_buffer_size - dma_buffer_size % sample_size;
	else if (size < sample_size)
		size = sample_size;

	return size;
}

/* figures out what counter values to use based on command */
static void labpc_adc_timing(struct comedi_device *dev, struct comedi_cmd *cmd)
{
	/* max value for 16 bit counter in mode 2 */
	const int max_counter_value = 0x10000;
	/* min value for 16 bit counter in mode 2 */
	const int min_counter_value = 2;
	unsigned int base_period;

	/*
	 * if both convert and scan triggers are TRIG_TIMER, then they
	 * both rely on counter b0
	 */
	if (labpc_ai_convert_period(cmd) && labpc_ai_scan_period(cmd)) {
		/*
		 * pick the lowest b0 divisor value we can (for maximum input
		 * clock speed on convert and scan counters)
		 */
		devpriv->divisor_b0 = (labpc_ai_scan_period(cmd) - 1) /
		    (LABPC_TIMER_BASE * max_counter_value) + 1;
		if (devpriv->divisor_b0 < min_counter_value)
			devpriv->divisor_b0 = min_counter_value;
		if (devpriv->divisor_b0 > max_counter_value)
			devpriv->divisor_b0 = max_counter_value;

		base_period = LABPC_TIMER_BASE * devpriv->divisor_b0;

		/*  set a0 for conversion frequency and b1 for scan frequency */
		switch (cmd->flags & TRIG_ROUND_MASK) {
		default:
		case TRIG_ROUND_NEAREST:
			devpriv->divisor_a0 =
			    (labpc_ai_convert_period(cmd) +
			     (base_period / 2)) / base_period;
			devpriv->divisor_b1 =
			    (labpc_ai_scan_period(cmd) +
			     (base_period / 2)) / base_period;
			break;
		case TRIG_ROUND_UP:
			devpriv->divisor_a0 =
			    (labpc_ai_convert_period(cmd) + (base_period -
							     1)) / base_period;
			devpriv->divisor_b1 =
			    (labpc_ai_scan_period(cmd) + (base_period -
							  1)) / base_period;
			break;
		case TRIG_ROUND_DOWN:
			devpriv->divisor_a0 =
			    labpc_ai_convert_period(cmd) / base_period;
			devpriv->divisor_b1 =
			    labpc_ai_scan_period(cmd) / base_period;
			break;
		}
		/*  make sure a0 and b1 values are acceptable */
		if (devpriv->divisor_a0 < min_counter_value)
			devpriv->divisor_a0 = min_counter_value;
		if (devpriv->divisor_a0 > max_counter_value)
			devpriv->divisor_a0 = max_counter_value;
		if (devpriv->divisor_b1 < min_counter_value)
			devpriv->divisor_b1 = min_counter_value;
		if (devpriv->divisor_b1 > max_counter_value)
			devpriv->divisor_b1 = max_counter_value;
		/*  write corrected timings to command */
		labpc_set_ai_convert_period(cmd,
					    base_period * devpriv->divisor_a0);
		labpc_set_ai_scan_period(cmd,
					 base_period * devpriv->divisor_b1);
		/*
		 * if only one TRIG_TIMER is used, we can employ the generic
		 * cascaded timing functions
		 */
	} else if (labpc_ai_scan_period(cmd)) {
		unsigned int scan_period;

		scan_period = labpc_ai_scan_period(cmd);
		/*
		 * calculate cascaded counter values
		 * that give desired scan timing
		 */
		i8253_cascade_ns_to_timer_2div(LABPC_TIMER_BASE,
					       &(devpriv->divisor_b1),
					       &(devpriv->divisor_b0),
					       &scan_period,
					       cmd->flags & TRIG_ROUND_MASK);
		labpc_set_ai_scan_period(cmd, scan_period);
	} else if (labpc_ai_convert_period(cmd)) {
		unsigned int convert_period;

		convert_period = labpc_ai_convert_period(cmd);
		/*
		 * calculate cascaded counter values
		 * that give desired conversion timing
		 */
		i8253_cascade_ns_to_timer_2div(LABPC_TIMER_BASE,
					       &(devpriv->divisor_a0),
					       &(devpriv->divisor_b0),
					       &convert_period,
					       cmd->flags & TRIG_ROUND_MASK);
		labpc_set_ai_convert_period(cmd, convert_period);
	}
}

static int labpc_dio_mem_callback(int dir, int port, int data,
				  unsigned long iobase)
{
	if (dir) {
		writeb(data, (void *)(iobase + port));
		return 0;
	} else {
		return readb((void *)(iobase + port));
	}
}

/* lowlevel write to eeprom/dac */
static void labpc_serial_out(struct comedi_device *dev, unsigned int value,
			     unsigned int value_width)
{
	int i;

	for (i = 1; i <= value_width; i++) {
		/*  clear serial clock */
		devpriv->command5_bits &= ~SCLOCK_BIT;
		/*  send bits most significant bit first */
		if (value & (1 << (value_width - i)))
			devpriv->command5_bits |= SDATA_BIT;
		else
			devpriv->command5_bits &= ~SDATA_BIT;
		udelay(1);
		devpriv->write_byte(devpriv->command5_bits,
				    dev->iobase + COMMAND5_REG);
		/*  set clock to load bit */
		devpriv->command5_bits |= SCLOCK_BIT;
		udelay(1);
		devpriv->write_byte(devpriv->command5_bits,
				    dev->iobase + COMMAND5_REG);
	}
}

/* lowlevel read from eeprom */
static unsigned int labpc_serial_in(struct comedi_device *dev)
{
	unsigned int value = 0;
	int i;
	const int value_width = 8;	/*  number of bits wide values are */

	for (i = 1; i <= value_width; i++) {
		/*  set serial clock */
		devpriv->command5_bits |= SCLOCK_BIT;
		udelay(1);
		devpriv->write_byte(devpriv->command5_bits,
				    dev->iobase + COMMAND5_REG);
		/*  clear clock bit */
		devpriv->command5_bits &= ~SCLOCK_BIT;
		udelay(1);
		devpriv->write_byte(devpriv->command5_bits,
				    dev->iobase + COMMAND5_REG);
		/*  read bits most significant bit first */
		udelay(1);
		devpriv->status2_bits =
		    devpriv->read_byte(dev->iobase + STATUS2_REG);
		if (devpriv->status2_bits & EEPROM_OUT_BIT)
			value |= 1 << (value_width - i);
	}

	return value;
}

static unsigned int labpc_eeprom_read(struct comedi_device *dev,
				      unsigned int address)
{
	unsigned int value;
	/*  bits to tell eeprom to expect a read */
	const int read_instruction = 0x3;
	/*  8 bit write lengths to eeprom */
	const int write_length = 8;

	/*  enable read/write to eeprom */
	devpriv->command5_bits &= ~EEPROM_EN_BIT;
	udelay(1);
	devpriv->write_byte(devpriv->command5_bits, dev->iobase + COMMAND5_REG);
	devpriv->command5_bits |= EEPROM_EN_BIT | EEPROM_WRITE_UNPROTECT_BIT;
	udelay(1);
	devpriv->write_byte(devpriv->command5_bits, dev->iobase + COMMAND5_REG);

	/*  send read instruction */
	labpc_serial_out(dev, read_instruction, write_length);
	/*  send 8 bit address to read from */
	labpc_serial_out(dev, address, write_length);
	/*  read result */
	value = labpc_serial_in(dev);

	/*  disable read/write to eeprom */
	devpriv->command5_bits &= ~EEPROM_EN_BIT & ~EEPROM_WRITE_UNPROTECT_BIT;
	udelay(1);
	devpriv->write_byte(devpriv->command5_bits, dev->iobase + COMMAND5_REG);

	return value;
}

static int labpc_eeprom_write(struct comedi_device *dev,
				unsigned int address, unsigned int value)
{
	const int write_enable_instruction = 0x6;
	const int write_instruction = 0x2;
	const int write_length = 8;	/*  8 bit write lengths to eeprom */
	const int write_in_progress_bit = 0x1;
	const int timeout = 10000;
	int i;

	/*  make sure there isn't already a write in progress */
	for (i = 0; i < timeout; i++) {
		if ((labpc_eeprom_read_status(dev) & write_in_progress_bit) ==
		    0)
			break;
	}
	if (i == timeout) {
		comedi_error(dev, "eeprom write timed out");
		return -ETIME;
	}
	/*  update software copy of eeprom */
	devpriv->eeprom_data[address] = value;

	/*  enable read/write to eeprom */
	devpriv->command5_bits &= ~EEPROM_EN_BIT;
	udelay(1);
	devpriv->write_byte(devpriv->command5_bits, dev->iobase + COMMAND5_REG);
	devpriv->command5_bits |= EEPROM_EN_BIT | EEPROM_WRITE_UNPROTECT_BIT;
	udelay(1);
	devpriv->write_byte(devpriv->command5_bits, dev->iobase + COMMAND5_REG);

	/*  send write_enable instruction */
	labpc_serial_out(dev, write_enable_instruction, write_length);
	devpriv->command5_bits &= ~EEPROM_EN_BIT;
	udelay(1);
	devpriv->write_byte(devpriv->command5_bits, dev->iobase + COMMAND5_REG);

	/*  send write instruction */
	devpriv->command5_bits |= EEPROM_EN_BIT;
	udelay(1);
	devpriv->write_byte(devpriv->command5_bits, dev->iobase + COMMAND5_REG);
	labpc_serial_out(dev, write_instruction, write_length);
	/*  send 8 bit address to write to */
	labpc_serial_out(dev, address, write_length);
	/*  write value */
	labpc_serial_out(dev, value, write_length);
	devpriv->command5_bits &= ~EEPROM_EN_BIT;
	udelay(1);
	devpriv->write_byte(devpriv->command5_bits, dev->iobase + COMMAND5_REG);

	/*  disable read/write to eeprom */
	devpriv->command5_bits &= ~EEPROM_EN_BIT & ~EEPROM_WRITE_UNPROTECT_BIT;
	udelay(1);
	devpriv->write_byte(devpriv->command5_bits, dev->iobase + COMMAND5_REG);

	return 0;
}

static unsigned int labpc_eeprom_read_status(struct comedi_device *dev)
{
	unsigned int value;
	const int read_status_instruction = 0x5;
	const int write_length = 8;	/*  8 bit write lengths to eeprom */

	/*  enable read/write to eeprom */
	devpriv->command5_bits &= ~EEPROM_EN_BIT;
	udelay(1);
	devpriv->write_byte(devpriv->command5_bits, dev->iobase + COMMAND5_REG);
	devpriv->command5_bits |= EEPROM_EN_BIT | EEPROM_WRITE_UNPROTECT_BIT;
	udelay(1);
	devpriv->write_byte(devpriv->command5_bits, dev->iobase + COMMAND5_REG);

	/*  send read status instruction */
	labpc_serial_out(dev, read_status_instruction, write_length);
	/*  read result */
	value = labpc_serial_in(dev);

	/*  disable read/write to eeprom */
	devpriv->command5_bits &= ~EEPROM_EN_BIT & ~EEPROM_WRITE_UNPROTECT_BIT;
	udelay(1);
	devpriv->write_byte(devpriv->command5_bits, dev->iobase + COMMAND5_REG);

	return value;
}

/* writes to 8 bit calibration dacs */
static void write_caldac(struct comedi_device *dev, unsigned int channel,
			 unsigned int value)
{
	if (value == devpriv->caldac[channel])
		return;
	devpriv->caldac[channel] = value;

	/*  clear caldac load bit and make sure we don't write to eeprom */
	devpriv->command5_bits &=
	    ~CALDAC_LOAD_BIT & ~EEPROM_EN_BIT & ~EEPROM_WRITE_UNPROTECT_BIT;
	udelay(1);
	devpriv->write_byte(devpriv->command5_bits, dev->iobase + COMMAND5_REG);

	/*  write 4 bit channel */
	labpc_serial_out(dev, channel, 4);
	/*  write 8 bit caldac value */
	labpc_serial_out(dev, value, 8);

	/*  set and clear caldac bit to load caldac value */
	devpriv->command5_bits |= CALDAC_LOAD_BIT;
	udelay(1);
	devpriv->write_byte(devpriv->command5_bits, dev->iobase + COMMAND5_REG);
	devpriv->command5_bits &= ~CALDAC_LOAD_BIT;
	udelay(1);
	devpriv->write_byte(devpriv->command5_bits, dev->iobase + COMMAND5_REG);
}

#ifdef CONFIG_COMEDI_PCI
static int __devinit driver_labpc_pci_probe(struct pci_dev *dev,
					    const struct pci_device_id *ent)
{
	return comedi_pci_auto_config(dev, driver_labpc.driver_name);
}

static void __devexit driver_labpc_pci_remove(struct pci_dev *dev)
{
	comedi_pci_auto_unconfig(dev);
}

static struct pci_driver driver_labpc_pci_driver = {
	.id_table = labpc_pci_table,
	.probe = &driver_labpc_pci_probe,
	.remove = __devexit_p(&driver_labpc_pci_remove)
};

static int __init driver_labpc_init_module(void)
{
	int retval;

	retval = comedi_driver_register(&driver_labpc);
	if (retval < 0)
		return retval;

	driver_labpc_pci_driver.name = (char *)driver_labpc.driver_name;
	return pci_register_driver(&driver_labpc_pci_driver);
}

static void __exit driver_labpc_cleanup_module(void)
{
	pci_unregister_driver(&driver_labpc_pci_driver);
	comedi_driver_unregister(&driver_labpc);
}

module_init(driver_labpc_init_module);
module_exit(driver_labpc_cleanup_module);
#else
static int __init driver_labpc_init_module(void)
{
	return comedi_driver_register(&driver_labpc);
}

static void __exit driver_labpc_cleanup_module(void)
{
	comedi_driver_unregister(&driver_labpc);
}

module_init(driver_labpc_init_module);
module_exit(driver_labpc_cleanup_module);
#endif


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