Staging: comedi: add skeleton driver

Example skeleton comedi driver

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

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 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.
+ */
+typedef struct skel_board_struct {
+	const char *name;
+	int ai_chans;
+	int ai_bits;
+	int have_dio;
+} skel_board;
+static const 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 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 comedi_device struct.  */
+typedef struct {
+	int data;
+
+	/* would be useful for a PCI device */
+	struct pci_dev *pci_dev;
+
+	/* Used for AO readback */
+	lsampl_t ao_readback[2];
+} skel_private;
+/*
+ * most drivers define the following macro to make it easy to
+ * access the private structure.
+ */
+#define devpriv ((skel_private *)dev->private)
+
+/*
+ * 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 int skel_attach(comedi_device * dev, comedi_devconfig * it);
+static int skel_detach(comedi_device * dev);
+static 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(skel_board),
+      num_names:sizeof(skel_boards) / sizeof(skel_board),
+};
+
+static int skel_ai_rinsn(comedi_device * dev, comedi_subdevice * s,
+	comedi_insn * insn, lsampl_t * data);
+static int skel_ao_winsn(comedi_device * dev, comedi_subdevice * s,
+	comedi_insn * insn, lsampl_t * data);
+static int skel_ao_rinsn(comedi_device * dev, comedi_subdevice * s,
+	comedi_insn * insn, lsampl_t * data);
+static int skel_dio_insn_bits(comedi_device * dev, comedi_subdevice * s,
+	comedi_insn * insn, lsampl_t * data);
+static int skel_dio_insn_config(comedi_device * dev, comedi_subdevice * s,
+	comedi_insn * insn, lsampl_t * data);
+static int skel_ai_cmdtest(comedi_device * dev, comedi_subdevice * s,
+	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(comedi_device * dev, comedi_devconfig * it)
+{
+	comedi_subdevice *s;
+
+	printk("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(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;
+	}
+
+	printk("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(comedi_device * dev)
+{
+	printk("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(comedi_device * dev, comedi_subdevice * s,
+	comedi_insn * insn, lsampl_t * 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) {
+			/* rt_printk() should be used instead of printk()
+			 * whenever the code can be called from real-time. */
+			rt_printk("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(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_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(comedi_device * dev, comedi_subdevice * s,
+	comedi_insn * insn, lsampl_t * data)
+{
+	int i;
+	int chan = CR_CHAN(insn->chanspec);
+
+	printk("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(comedi_device * dev, comedi_subdevice * s,
+	comedi_insn * insn, lsampl_t * 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(comedi_device * dev, comedi_subdevice * s,
+	comedi_insn * insn, lsampl_t * 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(comedi_device * dev, comedi_subdevice * s,
+	comedi_insn * insn, lsampl_t * 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;
+}
+
+/*
+ * A convenient macro that defines init_module() and cleanup_module(),
+ * as necessary.
+ */
+COMEDI_INITCLEANUP(driver_skel);
+/* If you are writing a PCI driver you should use COMEDI_PCI_INITCLEANUP instead.
+*/
+// COMEDI_PCI_INITCLEANUP(driver_skel, skel_pci_table)