xref: /drivers/staging/comedi/drivers/skel.c

/*
    comedi/drivers/skel.c
    Skeleton code for a Comedi driver

    COMEDI - Linux Control and Measurement Device Interface
    Copyright (C) 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.

    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: skel
Description: Skeleton driver, an example for driver writers
Devices:
Author: ds
Updated: Mon, 18 Mar 2002 15:34:01 -0800
Status: works

This driver is a documented example on how Comedi drivers are
written.

Configuration Options:
  none
*/

/*
 * The previous block comment is used to automatically generate
 * documentation in Comedi and Comedilib.  The fields:
 *
 * Driver: the name of the driver
 * Description: a short phrase describing the driver.  Don't list boards.
 * Devices: a full list of the boards that attempt to be supported by
 *   the driver.  Format is "(manufacturer) board name [comedi name]",
 *   where comedi_name is the name that is used to configure the board.
 *   See the comment near board_name: in the struct comedi_driver structure
 *   below.  If (manufacturer) or [comedi name] is missing, the previous
 *   value is used.
 * Author: you
 * Updated: date when the _documentation_ was last updated.  Use 'date -R'
 *   to get a value for this.
 * Status: a one-word description of the status.  Valid values are:
 *   works - driver works correctly on most boards supported, and
 *     passes comedi_test.
 *   unknown - unknown.  Usually put there by ds.
 *   experimental - may not work in any particular release.  Author
 *     probably wants assistance testing it.
 *   bitrotten - driver has not been update in a long time, probably
 *     doesn't work, and probably is missing support for significant
 *     Comedi interface features.
 *   untested - author probably wrote it "blind", and is believed to
 *     work, but no confirmation.
 *
 * These headers should be followed by a blank line, and any comments
 * you wish to say about the driver.  The comment area is the place
 * to put any known bugs, limitations, unsupported features, supported
 * command triggers, whether or not commands are supported on particular
 * subdevices, etc.
 *
 * Somewhere in the comment should be information about configuration
 * options that are used with comedi_config.
 */

#include "../comedidev.h"

#include <linux/pci.h>		/* for PCI devices */

/* Imaginary registers for the imaginary board */

#define SKEL_SIZE 0

#define SKEL_START_AI_CONV	0
#define SKEL_AI_READ		0

/*
 * 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.
 */
struct skel_board {
	const char *name;
	int ai_chans;
	int ai_bits;
	int have_dio;
};

static const struct skel_board skel_boards[] = {
	{
	 .name = "skel-100",
	 .ai_chans = 16,
	 .ai_bits = 12,
	 .have_dio = 1,
	 },
	{
	 .name = "skel-200",
	 .ai_chans = 8,
	 .ai_bits = 16,
	 .have_dio = 0,
	 },
};

/* This is used by modprobe to translate PCI IDs to drivers.  Should
 * only be used for PCI and ISA-PnP devices */
/* Please add your PCI vendor ID to comedidev.h, and it will be forwarded
 * upstream. */
#define PCI_VENDOR_ID_SKEL 0xdafe
static DEFINE_PCI_DEVICE_TABLE(skel_pci_table) = {
	{
	PCI_VENDOR_ID_SKEL, 0x0100, PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0}, {
	PCI_VENDOR_ID_SKEL, 0x0200, PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0}, {
	0}
};

MODULE_DEVICE_TABLE(pci, skel_pci_table);

/*
 * Useful for shorthand access to the particular board structure
 */
#define thisboard ((const struct skel_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 struct comedi_device struct.
 */
struct skel_private {

	int data;

	/* would be useful for a PCI device */
	struct pci_dev *pci_dev;

	/* Used for AO readback */
	unsigned int ao_readback[2];
};

/*
 * most drivers define the following macro to make it easy to
 * access the private structure.
 */
#define devpriv ((struct skel_private *)dev->private)

/*
 * The struct 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 int skel_attach(struct comedi_device *dev, struct comedi_devconfig *it);
static int skel_detach(struct comedi_device *dev);
static struct comedi_driver driver_skel = {
	.driver_name = "dummy",
	.module = THIS_MODULE,
	.attach = skel_attach,
	.detach = skel_detach,
/* It is not necessary to implement the following members if you are
 * writing a driver for a ISA PnP or PCI card */
	/* Most drivers will support multiple types of boards by
	 * having an array of board structures.  These were defined
	 * in skel_boards[] above.  Note that the element 'name'
	 * was first in the structure -- Comedi uses this fact to
	 * extract the name of the board without knowing any details
	 * about the structure except for its length.
	 * When a device is attached (by comedi_config), the name
	 * of the device is given to Comedi, and Comedi tries to
	 * match it by going through the list of board names.  If
	 * there is a match, the address of the pointer is put
	 * into dev->board_ptr and driver->attach() is called.
	 *
	 * Note that these are not necessary if you can determine
	 * the type of board in software.  ISA PnP, PCI, and PCMCIA
	 * devices are such boards.
	 */
	.board_name = &skel_boards[0].name,
	.offset = sizeof(struct skel_board),
	.num_names = ARRAY_SIZE(skel_boards),
};

static int skel_ai_rinsn(struct comedi_device *dev, struct comedi_subdevice *s,
			 struct comedi_insn *insn, unsigned int *data);
static int skel_ao_winsn(struct comedi_device *dev, struct comedi_subdevice *s,
			 struct comedi_insn *insn, unsigned int *data);
static int skel_ao_rinsn(struct comedi_device *dev, struct comedi_subdevice *s,
			 struct comedi_insn *insn, unsigned int *data);
static int skel_dio_insn_bits(struct comedi_device *dev,
			      struct comedi_subdevice *s,
			      struct comedi_insn *insn, unsigned int *data);
static int skel_dio_insn_config(struct comedi_device *dev,
				struct comedi_subdevice *s,
				struct comedi_insn *insn, unsigned int *data);
static int skel_ai_cmdtest(struct comedi_device *dev,
			   struct comedi_subdevice *s, struct comedi_cmd *cmd);
static int skel_ns_to_timer(unsigned int *ns, int round);

/*
 * Attach is called by the Comedi core to configure the driver
 * for a particular board.  If you specified a board_name array
 * in the driver structure, dev->board_ptr contains that
 * address.
 */
static int skel_attach(struct comedi_device *dev, struct comedi_devconfig *it)
{
	struct comedi_subdevice *s;

	pr_info("comedi%d: skel: ", dev->minor);

/*
 * If you can probe the device to determine what device in a series
 * it is, this is the place to do it.  Otherwise, dev->board_ptr
 * should already be initialized.
 */
	/* dev->board_ptr = skel_probe(dev, it); */

/*
 * Initialize dev->board_name.  Note that we can use the "thisboard"
 * macro now, since we just initialized it in the last line.
 */
	dev->board_name = thisboard->name;

/*
 * Allocate the private structure area.  alloc_private() is a
 * convenient macro defined in comedidev.h.
 */
	if (alloc_private(dev, sizeof(struct skel_private)) < 0)
		return -ENOMEM;

/*
 * Allocate the subdevice structures.  alloc_subdevice() is a
 * convenient macro defined in comedidev.h.
 */
	if (alloc_subdevices(dev, 3) < 0)
		return -ENOMEM;

	s = dev->subdevices + 0;
	/* dev->read_subdev=s; */
	/* analog input subdevice */
	s->type = COMEDI_SUBD_AI;
	/* we support single-ended (ground) and differential */
	s->subdev_flags = SDF_READABLE | SDF_GROUND | SDF_DIFF;
	s->n_chan = thisboard->ai_chans;
	s->maxdata = (1 << thisboard->ai_bits) - 1;
	s->range_table = &range_bipolar10;
	s->len_chanlist = 16;	/* This is the maximum chanlist length that
				   the board can handle */
	s->insn_read = skel_ai_rinsn;
/*
*       s->subdev_flags |= SDF_CMD_READ;
*       s->do_cmd = skel_ai_cmd;
*/
	s->do_cmdtest = skel_ai_cmdtest;

	s = dev->subdevices + 1;
	/* analog output subdevice */
	s->type = COMEDI_SUBD_AO;
	s->subdev_flags = SDF_WRITABLE;
	s->n_chan = 1;
	s->maxdata = 0xffff;
	s->range_table = &range_bipolar5;
	s->insn_write = skel_ao_winsn;
	s->insn_read = skel_ao_rinsn;

	s = dev->subdevices + 2;
	/* digital i/o subdevice */
	if (thisboard->have_dio) {
		s->type = COMEDI_SUBD_DIO;
		s->subdev_flags = SDF_READABLE | SDF_WRITABLE;
		s->n_chan = 16;
		s->maxdata = 1;
		s->range_table = &range_digital;
		s->insn_bits = skel_dio_insn_bits;
		s->insn_config = skel_dio_insn_config;
	} else {
		s->type = COMEDI_SUBD_UNUSED;
	}

	pr_info("attached\n");

	return 0;
}

/*
 * _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 skel_detach(struct comedi_device *dev)
{
	pr_info("comedi%d: skel: remove\n", dev->minor);

	return 0;
}

/*
 * "instructions" read/write data in "one-shot" or "software-triggered"
 * mode.
 */
static int skel_ai_rinsn(struct comedi_device *dev, struct comedi_subdevice *s,
			 struct comedi_insn *insn, unsigned int *data)
{
	int n, i;
	unsigned int d;
	unsigned int status;

	/* a typical programming sequence */

	/* write channel to multiplexer */
	/* outw(chan,dev->iobase + SKEL_MUX); */

	/* don't wait for mux to settle */

	/* convert n samples */
	for (n = 0; n < insn->n; n++) {
		/* trigger conversion */
		/* outw(0,dev->iobase + SKEL_CONVERT); */

#define TIMEOUT 100
		/* wait for conversion to end */
		for (i = 0; i < TIMEOUT; i++) {
			status = 1;
			/* status = inb(dev->iobase + SKEL_STATUS); */
			if (status)
				break;
		}
		if (i == TIMEOUT) {
			/* printk() should be used instead of printk()
			 * whenever the code can be called from real-time. */
			pr_info("timeout\n");
			return -ETIMEDOUT;
		}

		/* read data */
		/* d = inw(dev->iobase + SKEL_AI_DATA); */
		d = 0;

		/* mangle the data as necessary */
		d ^= 1 << (thisboard->ai_bits - 1);

		data[n] = d;
	}

	/* return the number of samples read/written */
	return n;
}

static int skel_ai_cmdtest(struct comedi_device *dev,
			   struct comedi_subdevice *s, struct 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 compatibility 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_COUNT && cmd->stop_src != TRIG_NONE)
		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;
		skel_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;
		skel_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;
}

/* 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. */
static int skel_ns_to_timer(unsigned int *ns, int round)
{
	/* trivial timer */
	/* if your timing is done through two cascaded timers, the
	 * i8253_cascade_ns_to_timer() function in 8253.h can be
	 * very helpful.  There are also i8254_load() and i8254_mm_load()
	 * which can be used to load values into the ubiquitous 8254 counters
	 */

	return *ns;
}

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

	pr_info("skel_ao_winsn\n");
	/* Writing a list of values to an AO channel is probably not
	 * very useful, but that's how the interface is defined. */
	for (i = 0; i < insn->n; i++) {
		/* a typical programming sequence */
		/* outw(data[i],dev->iobase + SKEL_DA0 + chan); */
		devpriv->ao_readback[chan] = data[i];
	}

	/* return the number of samples read/written */
	return i;
}

/* AO subdevices should have a read insn as well as a write insn.
 * Usually this means copying a value stored in devpriv. */
static int skel_ao_rinsn(struct comedi_device *dev, struct comedi_subdevice *s,
			 struct comedi_insn *insn, unsigned int *data)
{
	int i;
	int chan = CR_CHAN(insn->chanspec);

	for (i = 0; i < insn->n; i++)
		data[i] = devpriv->ao_readback[chan];

	return i;
}

/* DIO devices are slightly special.  Although it is possible to
 * implement the insn_read/insn_write interface, it is much more
 * useful to applications if you implement the insn_bits interface.
 * This allows packed reading/writing of the DIO channels.  The
 * comedi core can convert between insn_bits and insn_read/write */
static int skel_dio_insn_bits(struct comedi_device *dev,
			      struct comedi_subdevice *s,
			      struct comedi_insn *insn, unsigned int *data)
{
	if (insn->n != 2)
		return -EINVAL;

	/* The insn data is a mask in data[0] and the new data
	 * in data[1], each channel cooresponding to a bit. */
	if (data[0]) {
		s->state &= ~data[0];
		s->state |= data[0] & data[1];
		/* Write out the new digital output lines */
		/* outw(s->state,dev->iobase + SKEL_DIO); */
	}

	/* on return, data[1] contains the value of the digital
	 * input and output lines. */
	/* data[1]=inw(dev->iobase + SKEL_DIO); */
	/* or we could just return the software copy of the output values if
	 * it was a purely digital output subdevice */
	/* data[1]=s->state; */

	return 2;
}

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

	/* The input or output configuration of each digital line is
	 * configured by a special insn_config instruction.  chanspec
	 * contains the channel to be changed, and data[0] contains the
	 * value COMEDI_INPUT or COMEDI_OUTPUT. */
	switch (data[0]) {
	case INSN_CONFIG_DIO_OUTPUT:
		s->io_bits |= 1 << chan;
		break;
	case INSN_CONFIG_DIO_INPUT:
		s->io_bits &= ~(1 << chan);
		break;
	case INSN_CONFIG_DIO_QUERY:
		data[1] =
		    (s->io_bits & (1 << chan)) ? COMEDI_OUTPUT : COMEDI_INPUT;
		return insn->n;
		break;
	default:
		return -EINVAL;
		break;
	}
	/* outw(s->io_bits,dev->iobase + SKEL_DIO_CONFIG); */

	return insn->n;
}

static int __init driver_skel_init_module(void)
{
	return comedi_driver_register(&driver_skel);
}

static void __exit driver_skel_cleanup_module(void)
{
	comedi_driver_unregister(&driver_skel);
}

module_init(driver_skel_init_module);
module_exit(driver_skel_cleanup_module);
/* If you are writing a PCI driver you should use COMEDI_PCI_INITCLEANUP
 * instead.
 */
/* COMEDI_PCI_INITCLEANUP(driver_skel, skel_pci_table) */

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