Staging: comedi: add cb_pcidda driver

Driver for the ComputerBoards / MeasurementComputing PCI-DDA series.

From: Ivan Martinez <ivanmr@altavista.com>
Cc: David Schleef <ds@schleef.org>
Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: Frank Mori Hess <fmhess@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/comedi/drivers/cb_pcidda.c

+/*
+    comedi/drivers/cb_pcidda.c
+    This intends to be a driver for the ComputerBoards / MeasurementComputing
+    PCI-DDA series.
+
+	 Copyright (C) 2001 Ivan Martinez <ivanmr@altavista.com>
+    Copyright (C) 2001 Frank Mori Hess <fmhess@users.sourceforge.net>
+
+    COMEDI - Linux Control and Measurement Device Interface
+    Copyright (C) 1997-8 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.
+
+    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: cb_pcidda
+Description: MeasurementComputing PCI-DDA series
+Author: Ivan Martinez <ivanmr@altavista.com>, Frank Mori Hess <fmhess@users.sourceforge.net>
+Status: Supports 08/16, 04/16, 02/16, 08/12, 04/12, and 02/12
+Devices: [Measurement Computing] PCI-DDA08/12 (cb_pcidda), PCI-DDA04/12,
+  PCI-DDA02/12, PCI-DDA08/16, PCI-DDA04/16, PCI-DDA02/16
+
+Configuration options:
+  [0] - PCI bus of device (optional)
+  [1] - PCI slot of device (optional)
+  If bus/slot is not specified, the first available PCI
+  device will be used.
+
+Only simple analog output writing is supported.
+
+So far it has only been tested with:
+  - PCI-DDA08/12
+Please report success/failure with other different cards to
+<comedi@comedi.org>.
+*/
+
+#include "../comedidev.h"
+
+#include "comedi_pci.h"
+#include "8255.h"
+
+#define PCI_VENDOR_ID_CB	0x1307	// PCI vendor number of ComputerBoards
+#define N_BOARDS	10	// Number of boards in cb_pcidda_boards
+#define EEPROM_SIZE	128	// number of entries in eeprom
+#define MAX_AO_CHANNELS 8	// maximum number of ao channels for supported boards
+
+/* PCI-DDA base addresses */
+#define DIGITALIO_BADRINDEX	2
+	// DIGITAL I/O is pci_dev->resource[2]
+#define DIGITALIO_SIZE 8
+	// DIGITAL I/O uses 8 I/O port addresses
+#define DAC_BADRINDEX	3
+	// DAC is pci_dev->resource[3]
+
+/* Digital I/O registers */
+#define PORT1A 0		// PORT 1A DATA
+
+#define PORT1B 1		// PORT 1B DATA
+
+#define PORT1C 2		// PORT 1C DATA
+
+#define CONTROL1 3		// CONTROL REGISTER 1
+
+#define PORT2A 4		// PORT 2A DATA
+
+#define PORT2B 5		// PORT 2B DATA
+
+#define PORT2C 6		// PORT 2C DATA
+
+#define CONTROL2 7		// CONTROL REGISTER 2
+
+/* DAC registers */
+#define DACONTROL	0	// D/A CONTROL REGISTER
+#define	SU	0000001		// Simultaneous update enabled
+#define NOSU	0000000		// Simultaneous update disabled
+#define	ENABLEDAC	0000002	// Enable specified DAC
+#define	DISABLEDAC	0000000	// Disable specified DAC
+#define RANGE2V5	0000000	// 2.5V
+#define RANGE5V	0000200		// 5V
+#define RANGE10V	0000300	// 10V
+#define UNIP	0000400		// Unipolar outputs
+#define BIP	0000000		// Bipolar outputs
+
+#define DACALIBRATION1	4	// D/A CALIBRATION REGISTER 1
+//write bits
+#define	SERIAL_IN_BIT	0x1	// serial data input for eeprom, caldacs, reference dac
+#define	CAL_CHANNEL_MASK	(0x7 << 1)
+#define	CAL_CHANNEL_BITS(channel)	(((channel) << 1) & CAL_CHANNEL_MASK)
+//read bits
+#define	CAL_COUNTER_MASK	0x1f
+#define	CAL_COUNTER_OVERFLOW_BIT	0x20	// calibration counter overflow status bit
+#define	AO_BELOW_REF_BIT	0x40	// analog output is less than reference dac voltage
+#define	SERIAL_OUT_BIT	0x80	// serial data out, for reading from eeprom
+
+#define DACALIBRATION2	6	// D/A CALIBRATION REGISTER 2
+#define	SELECT_EEPROM_BIT	0x1	// send serial data in to eeprom
+#define	DESELECT_REF_DAC_BIT	0x2	// don't send serial data to MAX542 reference dac
+#define	DESELECT_CALDAC_BIT(n)	(0x4 << (n))	// don't send serial data to caldac n
+#define	DUMMY_BIT	0x40	// manual says to set this bit with no explanation
+
+#define DADATA	8		// FIRST D/A DATA REGISTER (0)
+
+static const comedi_lrange cb_pcidda_ranges = {
+	6,
+	{
+			BIP_RANGE(10),
+			BIP_RANGE(5),
+			BIP_RANGE(2.5),
+			UNI_RANGE(10),
+			UNI_RANGE(5),
+			UNI_RANGE(2.5),
+		}
+};
+
+/*
+ * Board descriptions for two imaginary boards.  Describing the
+ * boards in this way is optional, and completely driver-dependent.
+ * Some drivers use arrays such as this, other do not.
+ */
+typedef struct cb_pcidda_board_struct {
+	const char *name;
+	char status;		// Driver status:
+	// 0 - tested
+	// 1 - manual read, not tested
+	// 2 - manual not read
+	unsigned short device_id;
+	int ao_chans;
+	int ao_bits;
+	const comedi_lrange *ranges;
+} cb_pcidda_board;
+static const cb_pcidda_board cb_pcidda_boards[] = {
+	{
+	      name:	"pci-dda02/12",
+	      status:	1,
+	      device_id:0x20,
+	      ao_chans:2,
+	      ao_bits:	12,
+	      ranges:	&cb_pcidda_ranges,
+		},
+	{
+	      name:	"pci-dda04/12",
+	      status:	1,
+	      device_id:0x21,
+	      ao_chans:4,
+	      ao_bits:	12,
+	      ranges:	&cb_pcidda_ranges,
+		},
+	{
+	      name:	"pci-dda08/12",
+	      status:	0,
+	      device_id:0x22,
+	      ao_chans:8,
+	      ao_bits:	12,
+	      ranges:	&cb_pcidda_ranges,
+		},
+	{
+	      name:	"pci-dda02/16",
+	      status:	2,
+	      device_id:0x23,
+	      ao_chans:2,
+	      ao_bits:	16,
+	      ranges:	&cb_pcidda_ranges,
+		},
+	{
+	      name:	"pci-dda04/16",
+	      status:	2,
+	      device_id:0x24,
+	      ao_chans:4,
+	      ao_bits:	16,
+	      ranges:	&cb_pcidda_ranges,
+		},
+	{
+	      name:	"pci-dda08/16",
+	      status:	0,
+	      device_id:0x25,
+	      ao_chans:8,
+	      ao_bits:	16,
+	      ranges:	&cb_pcidda_ranges,
+		},
+};
+
+static DEFINE_PCI_DEVICE_TABLE(cb_pcidda_pci_table) = {
+	{PCI_VENDOR_ID_CB, 0x0020, PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0},
+	{PCI_VENDOR_ID_CB, 0x0021, PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0},
+	{PCI_VENDOR_ID_CB, 0x0022, PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0},
+	{PCI_VENDOR_ID_CB, 0x0023, PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0},
+	{PCI_VENDOR_ID_CB, 0x0024, PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0},
+	{PCI_VENDOR_ID_CB, 0x0025, PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0},
+	{0}
+};
+
+MODULE_DEVICE_TABLE(pci, cb_pcidda_pci_table);
+
+/*
+ * Useful for shorthand access to the particular board structure
+ */
+#define thisboard ((const cb_pcidda_board *)dev->board_ptr)
+
+/* this structure is for data unique to this hardware driver.  If
+   several hardware drivers keep similar information in this structure,
+   feel free to suggest moving the variable to the comedi_device struct.  */
+typedef struct {
+	int data;
+
+	/* would be useful for a PCI device */
+	struct pci_dev *pci_dev;
+
+	unsigned long digitalio;
+	unsigned long dac;
+	//unsigned long control_status;
+	//unsigned long adc_fifo;
+	unsigned int dac_cal1_bits;	// bits last written to da calibration register 1
+	unsigned int ao_range[MAX_AO_CHANNELS];	// current range settings for output channels
+	u16 eeprom_data[EEPROM_SIZE];	// software copy of board's eeprom
+} cb_pcidda_private;
+
+/*
+ * most drivers define the following macro to make it easy to
+ * access the private structure.
+ */
+#define devpriv ((cb_pcidda_private *)dev->private)
+
+static int cb_pcidda_attach(comedi_device * dev, comedi_devconfig * it);
+static int cb_pcidda_detach(comedi_device * dev);
+//static int cb_pcidda_ai_rinsn(comedi_device *dev,comedi_subdevice *s,comedi_insn *insn,lsampl_t *data);
+static int cb_pcidda_ao_winsn(comedi_device * dev, comedi_subdevice * s,
+	comedi_insn * insn, lsampl_t * data);
+//static int cb_pcidda_ai_cmd(comedi_device *dev,comedi_subdevice *s);
+//static int cb_pcidda_ai_cmdtest(comedi_device *dev,comedi_subdevice *s, comedi_cmd *cmd);
+//static int cb_pcidda_ns_to_timer(unsigned int *ns,int round);
+static unsigned int cb_pcidda_serial_in(comedi_device * dev);
+static void cb_pcidda_serial_out(comedi_device * dev, unsigned int value,
+	unsigned int num_bits);
+static unsigned int cb_pcidda_read_eeprom(comedi_device * dev,
+	unsigned int address);
+static void cb_pcidda_calibrate(comedi_device * dev, unsigned int channel,
+	unsigned int range);
+
+/*
+ * The comedi_driver structure tells the Comedi core module
+ * which functions to call to configure/deconfigure (attach/detach)
+ * the board, and also about the kernel module that contains
+ * the device code.
+ */
+static comedi_driver driver_cb_pcidda = {
+      driver_name:"cb_pcidda",
+      module:THIS_MODULE,
+      attach:cb_pcidda_attach,
+      detach:cb_pcidda_detach,
+};
+
+/*
+ * Attach is called by the Comedi core to configure the driver
+ * for a particular board.
+ */
+static int cb_pcidda_attach(comedi_device * dev, comedi_devconfig * it)
+{
+	comedi_subdevice *s;
+	struct pci_dev *pcidev;
+	int index;
+
+	printk("comedi%d: cb_pcidda: ", dev->minor);
+
+/*
+ * Allocate the private structure area.
+ */
+	if (alloc_private(dev, sizeof(cb_pcidda_private)) < 0)
+		return -ENOMEM;
+
+/*
+ * Probe the device to determine what device in the series it is.
+ */
+	printk("\n");
+
+	for (pcidev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, NULL);
+		pcidev != NULL;
+		pcidev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, pcidev)) {
+		if (pcidev->vendor == PCI_VENDOR_ID_CB) {
+			if (it->options[0] || it->options[1]) {
+				if (pcidev->bus->number != it->options[0] ||
+					PCI_SLOT(pcidev->devfn) !=
+					it->options[1]) {
+					continue;
+				}
+			}
+			for (index = 0; index < N_BOARDS; index++) {
+				if (cb_pcidda_boards[index].device_id ==
+					pcidev->device) {
+					goto found;
+				}
+			}
+		}
+	}
+	if (!pcidev) {
+		printk("Not a ComputerBoards/MeasurementComputing card on requested position\n");
+		return -EIO;
+	}
+      found:
+	devpriv->pci_dev = pcidev;
+	dev->board_ptr = cb_pcidda_boards + index;
+	// "thisboard" macro can be used from here.
+	printk("Found %s at requested position\n", thisboard->name);
+
+	/*
+	 * Enable PCI device and request regions.
+	 */
+	if (comedi_pci_enable(pcidev, thisboard->name)) {
+		printk("cb_pcidda: failed to enable PCI device and request regions\n");
+		return -EIO;
+	}
+
+/*
+ * Allocate the I/O ports.
+ */
+	devpriv->digitalio =
+		pci_resource_start(devpriv->pci_dev, DIGITALIO_BADRINDEX);
+	devpriv->dac = pci_resource_start(devpriv->pci_dev, DAC_BADRINDEX);
+
+/*
+ * Warn about the status of the driver.
+ */
+	if (thisboard->status == 2)
+		printk("WARNING: DRIVER FOR THIS BOARD NOT CHECKED WITH MANUAL. " "WORKS ASSUMING FULL COMPATIBILITY WITH PCI-DDA08/12. " "PLEASE REPORT USAGE TO <ivanmr@altavista.com>.\n");
+
+/*
+ * Initialize dev->board_name.
+ */
+	dev->board_name = thisboard->name;
+
+/*
+ * Allocate the subdevice structures.
+ */
+	if (alloc_subdevices(dev, 3) < 0)
+		return -ENOMEM;
+
+	s = dev->subdevices + 0;
+	/* analog output subdevice */
+	s->type = COMEDI_SUBD_AO;
+	s->subdev_flags = SDF_WRITABLE;
+	s->n_chan = thisboard->ao_chans;
+	s->maxdata = (1 << thisboard->ao_bits) - 1;
+	s->range_table = thisboard->ranges;
+	s->insn_write = cb_pcidda_ao_winsn;
+//      s->subdev_flags |= SDF_CMD_READ;
+//      s->do_cmd = cb_pcidda_ai_cmd;
+//      s->do_cmdtest = cb_pcidda_ai_cmdtest;
+
+	// two 8255 digital io subdevices
+	s = dev->subdevices + 1;
+	subdev_8255_init(dev, s, NULL, devpriv->digitalio);
+	s = dev->subdevices + 2;
+	subdev_8255_init(dev, s, NULL, devpriv->digitalio + PORT2A);
+
+	printk(" eeprom:");
+	for (index = 0; index < EEPROM_SIZE; index++) {
+		devpriv->eeprom_data[index] = cb_pcidda_read_eeprom(dev, index);
+		printk(" %i:0x%x ", index, devpriv->eeprom_data[index]);
+	}
+	printk("\n");
+
+	// set calibrations dacs
+	for (index = 0; index < thisboard->ao_chans; index++)
+		cb_pcidda_calibrate(dev, index, devpriv->ao_range[index]);
+
+	return 1;
+}
+
+/*
+ * _detach is called to deconfigure a device.  It should deallocate
+ * resources.
+ * This function is also called when _attach() fails, so it should be
+ * careful not to release resources that were not necessarily
+ * allocated by _attach().  dev->private and dev->subdevices are
+ * deallocated automatically by the core.
+ */
+static int cb_pcidda_detach(comedi_device * dev)
+{
+/*
+ * Deallocate the I/O ports.
+ */
+	if (devpriv) {
+		if (devpriv->pci_dev) {
+			if (devpriv->dac) {
+				comedi_pci_disable(devpriv->pci_dev);
+			}
+			pci_dev_put(devpriv->pci_dev);
+		}
+	}
+	// cleanup 8255
+	if (dev->subdevices) {
+		subdev_8255_cleanup(dev, dev->subdevices + 1);
+		subdev_8255_cleanup(dev, dev->subdevices + 2);
+	}
+
+	printk("comedi%d: cb_pcidda: remove\n", dev->minor);
+
+	return 0;
+}
+
+/*
+ * I will program this later... ;-)
+ */
+#if 0
+static int cb_pcidda_ai_cmd(comedi_device * dev, comedi_subdevice * s)
+{
+	printk("cb_pcidda_ai_cmd\n");
+	printk("subdev: %d\n", cmd->subdev);
+	printk("flags: %d\n", cmd->flags);
+	printk("start_src: %d\n", cmd->start_src);
+	printk("start_arg: %d\n", cmd->start_arg);
+	printk("scan_begin_src: %d\n", cmd->scan_begin_src);
+	printk("convert_src: %d\n", cmd->convert_src);
+	printk("convert_arg: %d\n", cmd->convert_arg);
+	printk("scan_end_src: %d\n", cmd->scan_end_src);
+	printk("scan_end_arg: %d\n", cmd->scan_end_arg);
+	printk("stop_src: %d\n", cmd->stop_src);
+	printk("stop_arg: %d\n", cmd->stop_arg);
+	printk("chanlist_len: %d\n", cmd->chanlist_len);
+}
+#endif
+
+#if 0
+static int cb_pcidda_ai_cmdtest(comedi_device * dev, comedi_subdevice * s,
+	comedi_cmd * cmd)
+{
+	int err = 0;
+	int tmp;
+
+	/* cmdtest tests a particular command to see if it is valid.
+	 * Using the cmdtest ioctl, a user can create a valid cmd
+	 * and then have it executes by the cmd ioctl.
+	 *
+	 * cmdtest returns 1,2,3,4 or 0, depending on which tests
+	 * the command passes. */
+
+	/* step 1: make sure trigger sources are trivially valid */
+
+	tmp = cmd->start_src;
+	cmd->start_src &= TRIG_NOW;
+	if (!cmd->start_src || tmp != cmd->start_src)
+		err++;
+
+	tmp = cmd->scan_begin_src;
+	cmd->scan_begin_src &= TRIG_TIMER | 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;
+	cmd->stop_src &= TRIG_COUNT | TRIG_NONE;
+	if (!cmd->stop_src || tmp != cmd->stop_src)
+		err++;
+
+	if (err)
+		return 1;
+
+	/* step 2: make sure trigger sources are unique and mutually compatible */
+
+	/* note that mutual compatiblity is not an issue here */
+	if (cmd->scan_begin_src != TRIG_TIMER
+		&& cmd->scan_begin_src != TRIG_EXT)
+		err++;
+	if (cmd->convert_src != TRIG_TIMER && cmd->convert_src != TRIG_EXT)
+		err++;
+	if (cmd->stop_src != TRIG_TIMER && cmd->stop_src != TRIG_EXT)
+		err++;
+
+	if (err)
+		return 2;
+
+	/* step 3: make sure arguments are trivially compatible */
+
+	if (cmd->start_arg != 0) {
+		cmd->start_arg = 0;
+		err++;
+	}
+#define MAX_SPEED	10000	/* in nanoseconds */
+#define MIN_SPEED	1000000000	/* in nanoseconds */
+
+	if (cmd->scan_begin_src == TRIG_TIMER) {
+		if (cmd->scan_begin_arg < MAX_SPEED) {
+			cmd->scan_begin_arg = MAX_SPEED;
+			err++;
+		}
+		if (cmd->scan_begin_arg > MIN_SPEED) {
+			cmd->scan_begin_arg = MIN_SPEED;
+			err++;
+		}
+	} else {
+		/* external trigger */
+		/* should be level/edge, hi/lo specification here */
+		/* should specify multiple external triggers */
+		if (cmd->scan_begin_arg > 9) {
+			cmd->scan_begin_arg = 9;
+			err++;
+		}
+	}
+	if (cmd->convert_src == TRIG_TIMER) {
+		if (cmd->convert_arg < MAX_SPEED) {
+			cmd->convert_arg = MAX_SPEED;
+			err++;
+		}
+		if (cmd->convert_arg > MIN_SPEED) {
+			cmd->convert_arg = MIN_SPEED;
+			err++;
+		}
+	} else {
+		/* external trigger */
+		/* see above */
+		if (cmd->convert_arg > 9) {
+			cmd->convert_arg = 9;
+			err++;
+		}
+	}
+
+	if (cmd->scan_end_arg != cmd->chanlist_len) {
+		cmd->scan_end_arg = cmd->chanlist_len;
+		err++;
+	}
+	if (cmd->stop_src == TRIG_COUNT) {
+		if (cmd->stop_arg > 0x00ffffff) {
+			cmd->stop_arg = 0x00ffffff;
+			err++;
+		}
+	} else {
+		/* TRIG_NONE */
+		if (cmd->stop_arg != 0) {
+			cmd->stop_arg = 0;
+			err++;
+		}
+	}
+
+	if (err)
+		return 3;
+
+	/* step 4: fix up any arguments */
+
+	if (cmd->scan_begin_src == TRIG_TIMER) {
+		tmp = cmd->scan_begin_arg;
+		cb_pcidda_ns_to_timer(&cmd->scan_begin_arg,
+			cmd->flags & TRIG_ROUND_MASK);
+		if (tmp != cmd->scan_begin_arg)
+			err++;
+	}
+	if (cmd->convert_src == TRIG_TIMER) {
+		tmp = cmd->convert_arg;
+		cb_pcidda_ns_to_timer(&cmd->convert_arg,
+			cmd->flags & TRIG_ROUND_MASK);
+		if (tmp != cmd->convert_arg)
+			err++;
+		if (cmd->scan_begin_src == TRIG_TIMER &&
+			cmd->scan_begin_arg <
+			cmd->convert_arg * cmd->scan_end_arg) {
+			cmd->scan_begin_arg =
+				cmd->convert_arg * cmd->scan_end_arg;
+			err++;
+		}
+	}
+
+	if (err)
+		return 4;
+
+	return 0;
+}
+#endif
+
+/* This function doesn't require a particular form, this is just
+ * what happens to be used in some of the drivers.  It should
+ * convert ns nanoseconds to a counter value suitable for programming
+ * the device.  Also, it should adjust ns so that it cooresponds to
+ * the actual time that the device will use. */
+#if 0
+static int cb_pcidda_ns_to_timer(unsigned int *ns, int round)
+{
+	/* trivial timer */
+	return *ns;
+}
+#endif
+
+static int cb_pcidda_ao_winsn(comedi_device * dev, comedi_subdevice * s,
+	comedi_insn * insn, lsampl_t * data)
+{
+	unsigned int command;
+	unsigned int channel, range;
+
+	channel = CR_CHAN(insn->chanspec);
+	range = CR_RANGE(insn->chanspec);
+
+	// adjust calibration dacs if range has changed
+	if (range != devpriv->ao_range[channel])
+		cb_pcidda_calibrate(dev, channel, range);
+
+	/* output channel configuration */
+	command = NOSU | ENABLEDAC;
+
+	/* output channel range */
+	switch (range) {
+	case 0:
+		command |= BIP | RANGE10V;
+		break;
+	case 1:
+		command |= BIP | RANGE5V;
+		break;
+	case 2:
+		command |= BIP | RANGE2V5;
+		break;
+	case 3:
+		command |= UNIP | RANGE10V;
+		break;
+	case 4:
+		command |= UNIP | RANGE5V;
+		break;
+	case 5:
+		command |= UNIP | RANGE2V5;
+		break;
+	};
+
+	/* output channel specification */
+	command |= channel << 2;
+	outw(command, devpriv->dac + DACONTROL);
+
+	/* write data */
+	outw(data[0], devpriv->dac + DADATA + channel * 2);
+
+	/* return the number of samples read/written */
+	return 1;
+}
+
+// lowlevel read from eeprom
+static unsigned int cb_pcidda_serial_in(comedi_device * dev)
+{
+	unsigned int value = 0;
+	int i;
+	const int value_width = 16;	// number of bits wide values are
+
+	for (i = 1; i <= value_width; i++) {
+		// read bits most significant bit first
+		if (inw_p(devpriv->dac + DACALIBRATION1) & SERIAL_OUT_BIT) {
+			value |= 1 << (value_width - i);
+		}
+	}
+
+	return value;
+}
+
+// lowlevel write to eeprom/dac
+static void cb_pcidda_serial_out(comedi_device * dev, unsigned int value,
+	unsigned int num_bits)
+{
+	int i;
+
+	for (i = 1; i <= num_bits; i++) {
+		// send bits most significant bit first
+		if (value & (1 << (num_bits - i)))
+			devpriv->dac_cal1_bits |= SERIAL_IN_BIT;
+		else
+			devpriv->dac_cal1_bits &= ~SERIAL_IN_BIT;
+		outw_p(devpriv->dac_cal1_bits, devpriv->dac + DACALIBRATION1);
+	}
+}
+
+// reads a 16 bit value from board's eeprom
+static unsigned int cb_pcidda_read_eeprom(comedi_device * dev,
+	unsigned int address)
+{
+	unsigned int i;
+	unsigned int cal2_bits;
+	unsigned int value;
+	const int max_num_caldacs = 4;	// one caldac for every two dac channels
+	const int read_instruction = 0x6;	// bits to send to tell eeprom we want to read
+	const int instruction_length = 3;
+	const int address_length = 8;
+
+	// send serial output stream to eeprom
+	cal2_bits = SELECT_EEPROM_BIT | DESELECT_REF_DAC_BIT | DUMMY_BIT;
+	// deactivate caldacs (one caldac for every two channels)
+	for (i = 0; i < max_num_caldacs; i++) {
+		cal2_bits |= DESELECT_CALDAC_BIT(i);
+	}
+	outw_p(cal2_bits, devpriv->dac + DACALIBRATION2);
+
+	// tell eeprom we want to read
+	cb_pcidda_serial_out(dev, read_instruction, instruction_length);
+	// send address we want to read from
+	cb_pcidda_serial_out(dev, address, address_length);
+
+	value = cb_pcidda_serial_in(dev);
+
+	// deactivate eeprom
+	cal2_bits &= ~SELECT_EEPROM_BIT;
+	outw_p(cal2_bits, devpriv->dac + DACALIBRATION2);
+
+	return value;
+}
+
+// writes to 8 bit calibration dacs
+static void cb_pcidda_write_caldac(comedi_device * dev, unsigned int caldac,
+	unsigned int channel, unsigned int value)
+{
+	unsigned int cal2_bits;
+	unsigned int i;
+	const int num_channel_bits = 3;	// caldacs use 3 bit channel specification
+	const int num_caldac_bits = 8;	// 8 bit calibration dacs
+	const int max_num_caldacs = 4;	// one caldac for every two dac channels
+
+	/* write 3 bit channel */
+	cb_pcidda_serial_out(dev, channel, num_channel_bits);
+	// write 8 bit caldac value
+	cb_pcidda_serial_out(dev, value, num_caldac_bits);
+
+	// latch stream into appropriate caldac
+	// deselect reference dac
+	cal2_bits = DESELECT_REF_DAC_BIT | DUMMY_BIT;
+	// deactivate caldacs (one caldac for every two channels)
+	for (i = 0; i < max_num_caldacs; i++) {
+		cal2_bits |= DESELECT_CALDAC_BIT(i);
+	}
+	// activate the caldac we want
+	cal2_bits &= ~DESELECT_CALDAC_BIT(caldac);
+	outw_p(cal2_bits, devpriv->dac + DACALIBRATION2);
+	// deactivate caldac
+	cal2_bits |= DESELECT_CALDAC_BIT(caldac);
+	outw_p(cal2_bits, devpriv->dac + DACALIBRATION2);
+}
+
+// returns caldac that calibrates given analog out channel
+static unsigned int caldac_number(unsigned int channel)
+{
+	return channel / 2;
+}
+
+// returns caldac channel that provides fine gain for given ao channel
+static unsigned int fine_gain_channel(unsigned int ao_channel)
+{
+	return 4 * (ao_channel % 2);
+}
+
+// returns caldac channel that provides coarse gain for given ao channel
+static unsigned int coarse_gain_channel(unsigned int ao_channel)
+{
+	return 1 + 4 * (ao_channel % 2);
+}
+
+// returns caldac channel that provides coarse offset for given ao channel
+static unsigned int coarse_offset_channel(unsigned int ao_channel)
+{
+	return 2 + 4 * (ao_channel % 2);
+}
+
+// returns caldac channel that provides fine offset for given ao channel
+static unsigned int fine_offset_channel(unsigned int ao_channel)
+{
+	return 3 + 4 * (ao_channel % 2);
+}
+
+// returns eeprom address that provides offset for given ao channel and range
+static unsigned int offset_eeprom_address(unsigned int ao_channel,
+	unsigned int range)
+{
+	return 0x7 + 2 * range + 12 * ao_channel;
+}
+
+// returns eeprom address that provides gain calibration for given ao channel and range
+static unsigned int gain_eeprom_address(unsigned int ao_channel,
+	unsigned int range)
+{
+	return 0x8 + 2 * range + 12 * ao_channel;
+}
+
+// returns upper byte of eeprom entry, which gives the coarse adjustment values
+static unsigned int eeprom_coarse_byte(unsigned int word)
+{
+	return (word >> 8) & 0xff;
+}
+
+// returns lower byte of eeprom entry, which gives the fine adjustment values
+static unsigned int eeprom_fine_byte(unsigned int word)
+{
+	return word & 0xff;
+}
+
+// set caldacs to eeprom values for given channel and range
+static void cb_pcidda_calibrate(comedi_device * dev, unsigned int channel,
+	unsigned int range)
+{
+	unsigned int coarse_offset, fine_offset, coarse_gain, fine_gain;
+
+	// remember range so we can tell when we need to readjust calibration
+	devpriv->ao_range[channel] = range;
+
+	// get values from eeprom data
+	coarse_offset =
+		eeprom_coarse_byte(devpriv->
+		eeprom_data[offset_eeprom_address(channel, range)]);
+	fine_offset =
+		eeprom_fine_byte(devpriv->
+		eeprom_data[offset_eeprom_address(channel, range)]);
+	coarse_gain =
+		eeprom_coarse_byte(devpriv->
+		eeprom_data[gain_eeprom_address(channel, range)]);
+	fine_gain =
+		eeprom_fine_byte(devpriv->
+		eeprom_data[gain_eeprom_address(channel, range)]);
+
+	// set caldacs
+	cb_pcidda_write_caldac(dev, caldac_number(channel),
+		coarse_offset_channel(channel), coarse_offset);
+	cb_pcidda_write_caldac(dev, caldac_number(channel),
+		fine_offset_channel(channel), fine_offset);
+	cb_pcidda_write_caldac(dev, caldac_number(channel),
+		coarse_gain_channel(channel), coarse_gain);
+	cb_pcidda_write_caldac(dev, caldac_number(channel),
+		fine_gain_channel(channel), fine_gain);
+}
+
+/*
+ * A convenient macro that defines init_module() and cleanup_module(),
+ * as necessary.
+ */
+COMEDI_PCI_INITCLEANUP(driver_cb_pcidda, cb_pcidda_pci_table);