3 Skeleton code for a Comedi driver
5 COMEDI - Linux Control and Measurement Device Interface
6 Copyright (C) 2000 David A. Schleef <ds@schleef.org>
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2 of the License, or
11 (at your option) any later version.
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with this program; if not, write to the Free Software
20 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
25 Description: Skeleton driver, an example for driver writers
28 Updated: Mon, 18 Mar 2002 15:34:01 -0800
31 This driver is a documented example on how Comedi drivers are
34 Configuration Options:
39 * The previous block comment is used to automatically generate
40 * documentation in Comedi and Comedilib. The fields:
42 * Driver: the name of the driver
43 * Description: a short phrase describing the driver. Don't list boards.
44 * Devices: a full list of the boards that attempt to be supported by
45 * the driver. Format is "(manufacturer) board name [comedi name]",
46 * where comedi_name is the name that is used to configure the board.
47 * See the comment near board_name: in the struct comedi_driver structure
48 * below. If (manufacturer) or [comedi name] is missing, the previous
51 * Updated: date when the _documentation_ was last updated. Use 'date -R'
52 * to get a value for this.
53 * Status: a one-word description of the status. Valid values are:
54 * works - driver works correctly on most boards supported, and
56 * unknown - unknown. Usually put there by ds.
57 * experimental - may not work in any particular release. Author
58 * probably wants assistance testing it.
59 * bitrotten - driver has not been update in a long time, probably
60 * doesn't work, and probably is missing support for significant
61 * Comedi interface features.
62 * untested - author probably wrote it "blind", and is believed to
63 * work, but no confirmation.
65 * These headers should be followed by a blank line, and any comments
66 * you wish to say about the driver. The comment area is the place
67 * to put any known bugs, limitations, unsupported features, supported
68 * command triggers, whether or not commands are supported on particular
71 * Somewhere in the comment should be information about configuration
72 * options that are used with comedi_config.
75 #include "../comedidev.h"
77 #include <linux/pci.h> /* for PCI devices */
79 /* Imaginary registers for the imaginary board */
83 #define SKEL_START_AI_CONV 0
84 #define SKEL_AI_READ 0
87 * Board descriptions for two imaginary boards. Describing the
88 * boards in this way is optional, and completely driver-dependent.
89 * Some drivers use arrays such as this, other do not.
98 static const struct skel_board skel_boards[] = {
113 /* This is used by modprobe to translate PCI IDs to drivers. Should
114 * only be used for PCI and ISA-PnP devices */
115 /* Please add your PCI vendor ID to comedidev.h, and it will be forwarded
117 #define PCI_VENDOR_ID_SKEL 0xdafe
118 static DEFINE_PCI_DEVICE_TABLE(skel_pci_table) = {
120 PCI_VENDOR_ID_SKEL, 0x0100, PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0}, {
121 PCI_VENDOR_ID_SKEL, 0x0200, PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0}, {
125 MODULE_DEVICE_TABLE(pci, skel_pci_table);
128 * Useful for shorthand access to the particular board structure
130 #define thisboard ((const struct skel_board *)dev->board_ptr)
132 /* this structure is for data unique to this hardware driver. If
133 several hardware drivers keep similar information in this structure,
134 feel free to suggest moving the variable to the struct comedi_device struct. */
135 struct skel_private {
139 /* would be useful for a PCI device */
140 struct pci_dev *pci_dev;
142 /* Used for AO readback */
143 unsigned int ao_readback[2];
147 * most drivers define the following macro to make it easy to
148 * access the private structure.
150 #define devpriv ((struct skel_private *)dev->private)
153 * The struct comedi_driver structure tells the Comedi core module
154 * which functions to call to configure/deconfigure (attach/detach)
155 * the board, and also about the kernel module that contains
158 static int skel_attach(struct comedi_device *dev, struct comedi_devconfig *it);
159 static int skel_detach(struct comedi_device *dev);
160 static struct comedi_driver driver_skel = {
161 .driver_name = "dummy",
162 .module = THIS_MODULE,
163 .attach = skel_attach,
164 .detach = skel_detach,
165 /* It is not necessary to implement the following members if you are
166 * writing a driver for a ISA PnP or PCI card */
167 /* Most drivers will support multiple types of boards by
168 * having an array of board structures. These were defined
169 * in skel_boards[] above. Note that the element 'name'
170 * was first in the structure -- Comedi uses this fact to
171 * extract the name of the board without knowing any details
172 * about the structure except for its length.
173 * When a device is attached (by comedi_config), the name
174 * of the device is given to Comedi, and Comedi tries to
175 * match it by going through the list of board names. If
176 * there is a match, the address of the pointer is put
177 * into dev->board_ptr and driver->attach() is called.
179 * Note that these are not necessary if you can determine
180 * the type of board in software. ISA PnP, PCI, and PCMCIA
181 * devices are such boards.
183 .board_name = &skel_boards[0].name,
184 .offset = sizeof(struct skel_board),
185 .num_names = ARRAY_SIZE(skel_boards),
188 static int skel_ai_rinsn(struct comedi_device *dev, struct comedi_subdevice *s,
189 struct comedi_insn *insn, unsigned int *data);
190 static int skel_ao_winsn(struct comedi_device *dev, struct comedi_subdevice *s,
191 struct comedi_insn *insn, unsigned int *data);
192 static int skel_ao_rinsn(struct comedi_device *dev, struct comedi_subdevice *s,
193 struct comedi_insn *insn, unsigned int *data);
194 static int skel_dio_insn_bits(struct comedi_device *dev,
195 struct comedi_subdevice *s,
196 struct comedi_insn *insn, unsigned int *data);
197 static int skel_dio_insn_config(struct comedi_device *dev,
198 struct comedi_subdevice *s,
199 struct comedi_insn *insn, unsigned int *data);
200 static int skel_ai_cmdtest(struct comedi_device *dev,
201 struct comedi_subdevice *s, struct comedi_cmd *cmd);
202 static int skel_ns_to_timer(unsigned int *ns, int round);
205 * Attach is called by the Comedi core to configure the driver
206 * for a particular board. If you specified a board_name array
207 * in the driver structure, dev->board_ptr contains that
210 static int skel_attach(struct comedi_device *dev, struct comedi_devconfig *it)
212 struct comedi_subdevice *s;
214 printk("comedi%d: skel: ", dev->minor);
217 * If you can probe the device to determine what device in a series
218 * it is, this is the place to do it. Otherwise, dev->board_ptr
219 * should already be initialized.
221 /* dev->board_ptr = skel_probe(dev, it); */
224 * Initialize dev->board_name. Note that we can use the "thisboard"
225 * macro now, since we just initialized it in the last line.
227 dev->board_name = thisboard->name;
230 * Allocate the private structure area. alloc_private() is a
231 * convenient macro defined in comedidev.h.
233 if (alloc_private(dev, sizeof(struct skel_private)) < 0)
237 * Allocate the subdevice structures. alloc_subdevice() is a
238 * convenient macro defined in comedidev.h.
240 if (alloc_subdevices(dev, 3) < 0)
243 s = dev->subdevices + 0;
244 /* dev->read_subdev=s; */
245 /* analog input subdevice */
246 s->type = COMEDI_SUBD_AI;
247 /* we support single-ended (ground) and differential */
248 s->subdev_flags = SDF_READABLE | SDF_GROUND | SDF_DIFF;
249 s->n_chan = thisboard->ai_chans;
250 s->maxdata = (1 << thisboard->ai_bits) - 1;
251 s->range_table = &range_bipolar10;
252 s->len_chanlist = 16; /* This is the maximum chanlist length that
253 the board can handle */
254 s->insn_read = skel_ai_rinsn;
256 * s->subdev_flags |= SDF_CMD_READ;
257 * s->do_cmd = skel_ai_cmd;
259 s->do_cmdtest = skel_ai_cmdtest;
261 s = dev->subdevices + 1;
262 /* analog output subdevice */
263 s->type = COMEDI_SUBD_AO;
264 s->subdev_flags = SDF_WRITABLE;
267 s->range_table = &range_bipolar5;
268 s->insn_write = skel_ao_winsn;
269 s->insn_read = skel_ao_rinsn;
271 s = dev->subdevices + 2;
272 /* digital i/o subdevice */
273 if (thisboard->have_dio) {
274 s->type = COMEDI_SUBD_DIO;
275 s->subdev_flags = SDF_READABLE | SDF_WRITABLE;
278 s->range_table = &range_digital;
279 s->insn_bits = skel_dio_insn_bits;
280 s->insn_config = skel_dio_insn_config;
282 s->type = COMEDI_SUBD_UNUSED;
285 printk("attached\n");
291 * _detach is called to deconfigure a device. It should deallocate
293 * This function is also called when _attach() fails, so it should be
294 * careful not to release resources that were not necessarily
295 * allocated by _attach(). dev->private and dev->subdevices are
296 * deallocated automatically by the core.
298 static int skel_detach(struct comedi_device *dev)
300 printk("comedi%d: skel: remove\n", dev->minor);
306 * "instructions" read/write data in "one-shot" or "software-triggered"
309 static int skel_ai_rinsn(struct comedi_device *dev, struct comedi_subdevice *s,
310 struct comedi_insn *insn, unsigned int *data)
316 /* a typical programming sequence */
318 /* write channel to multiplexer */
319 /* outw(chan,dev->iobase + SKEL_MUX); */
321 /* don't wait for mux to settle */
323 /* convert n samples */
324 for (n = 0; n < insn->n; n++) {
325 /* trigger conversion */
326 /* outw(0,dev->iobase + SKEL_CONVERT); */
329 /* wait for conversion to end */
330 for (i = 0; i < TIMEOUT; i++) {
332 /* status = inb(dev->iobase + SKEL_STATUS); */
337 /* printk() should be used instead of printk()
338 * whenever the code can be called from real-time. */
344 /* d = inw(dev->iobase + SKEL_AI_DATA); */
347 /* mangle the data as necessary */
348 d ^= 1 << (thisboard->ai_bits - 1);
353 /* return the number of samples read/written */
357 static int skel_ai_cmdtest(struct comedi_device *dev,
358 struct comedi_subdevice *s, struct comedi_cmd *cmd)
363 /* cmdtest tests a particular command to see if it is valid.
364 * Using the cmdtest ioctl, a user can create a valid cmd
365 * and then have it executes by the cmd ioctl.
367 * cmdtest returns 1,2,3,4 or 0, depending on which tests
368 * the command passes. */
370 /* step 1: make sure trigger sources are trivially valid */
372 tmp = cmd->start_src;
373 cmd->start_src &= TRIG_NOW;
374 if (!cmd->start_src || tmp != cmd->start_src)
377 tmp = cmd->scan_begin_src;
378 cmd->scan_begin_src &= TRIG_TIMER | TRIG_EXT;
379 if (!cmd->scan_begin_src || tmp != cmd->scan_begin_src)
382 tmp = cmd->convert_src;
383 cmd->convert_src &= TRIG_TIMER | TRIG_EXT;
384 if (!cmd->convert_src || tmp != cmd->convert_src)
387 tmp = cmd->scan_end_src;
388 cmd->scan_end_src &= TRIG_COUNT;
389 if (!cmd->scan_end_src || tmp != cmd->scan_end_src)
393 cmd->stop_src &= TRIG_COUNT | TRIG_NONE;
394 if (!cmd->stop_src || tmp != cmd->stop_src)
400 /* step 2: make sure trigger sources are unique and mutually compatible */
402 /* note that mutual compatibility is not an issue here */
403 if (cmd->scan_begin_src != TRIG_TIMER &&
404 cmd->scan_begin_src != TRIG_EXT)
406 if (cmd->convert_src != TRIG_TIMER && cmd->convert_src != TRIG_EXT)
408 if (cmd->stop_src != TRIG_COUNT && cmd->stop_src != TRIG_NONE)
414 /* step 3: make sure arguments are trivially compatible */
416 if (cmd->start_arg != 0) {
420 #define MAX_SPEED 10000 /* in nanoseconds */
421 #define MIN_SPEED 1000000000 /* in nanoseconds */
423 if (cmd->scan_begin_src == TRIG_TIMER) {
424 if (cmd->scan_begin_arg < MAX_SPEED) {
425 cmd->scan_begin_arg = MAX_SPEED;
428 if (cmd->scan_begin_arg > MIN_SPEED) {
429 cmd->scan_begin_arg = MIN_SPEED;
433 /* external trigger */
434 /* should be level/edge, hi/lo specification here */
435 /* should specify multiple external triggers */
436 if (cmd->scan_begin_arg > 9) {
437 cmd->scan_begin_arg = 9;
441 if (cmd->convert_src == TRIG_TIMER) {
442 if (cmd->convert_arg < MAX_SPEED) {
443 cmd->convert_arg = MAX_SPEED;
446 if (cmd->convert_arg > MIN_SPEED) {
447 cmd->convert_arg = MIN_SPEED;
451 /* external trigger */
453 if (cmd->convert_arg > 9) {
454 cmd->convert_arg = 9;
459 if (cmd->scan_end_arg != cmd->chanlist_len) {
460 cmd->scan_end_arg = cmd->chanlist_len;
463 if (cmd->stop_src == TRIG_COUNT) {
464 if (cmd->stop_arg > 0x00ffffff) {
465 cmd->stop_arg = 0x00ffffff;
470 if (cmd->stop_arg != 0) {
479 /* step 4: fix up any arguments */
481 if (cmd->scan_begin_src == TRIG_TIMER) {
482 tmp = cmd->scan_begin_arg;
483 skel_ns_to_timer(&cmd->scan_begin_arg,
484 cmd->flags & TRIG_ROUND_MASK);
485 if (tmp != cmd->scan_begin_arg)
488 if (cmd->convert_src == TRIG_TIMER) {
489 tmp = cmd->convert_arg;
490 skel_ns_to_timer(&cmd->convert_arg,
491 cmd->flags & TRIG_ROUND_MASK);
492 if (tmp != cmd->convert_arg)
494 if (cmd->scan_begin_src == TRIG_TIMER &&
495 cmd->scan_begin_arg <
496 cmd->convert_arg * cmd->scan_end_arg) {
497 cmd->scan_begin_arg =
498 cmd->convert_arg * cmd->scan_end_arg;
509 /* This function doesn't require a particular form, this is just
510 * what happens to be used in some of the drivers. It should
511 * convert ns nanoseconds to a counter value suitable for programming
512 * the device. Also, it should adjust ns so that it cooresponds to
513 * the actual time that the device will use. */
514 static int skel_ns_to_timer(unsigned int *ns, int round)
517 /* if your timing is done through two cascaded timers, the
518 * i8253_cascade_ns_to_timer() function in 8253.h can be
519 * very helpful. There are also i8254_load() and i8254_mm_load()
520 * which can be used to load values into the ubiquitous 8254 counters
526 static int skel_ao_winsn(struct comedi_device *dev, struct comedi_subdevice *s,
527 struct comedi_insn *insn, unsigned int *data)
530 int chan = CR_CHAN(insn->chanspec);
532 printk("skel_ao_winsn\n");
533 /* Writing a list of values to an AO channel is probably not
534 * very useful, but that's how the interface is defined. */
535 for (i = 0; i < insn->n; i++) {
536 /* a typical programming sequence */
537 /* outw(data[i],dev->iobase + SKEL_DA0 + chan); */
538 devpriv->ao_readback[chan] = data[i];
541 /* return the number of samples read/written */
545 /* AO subdevices should have a read insn as well as a write insn.
546 * Usually this means copying a value stored in devpriv. */
547 static int skel_ao_rinsn(struct comedi_device *dev, struct comedi_subdevice *s,
548 struct comedi_insn *insn, unsigned int *data)
551 int chan = CR_CHAN(insn->chanspec);
553 for (i = 0; i < insn->n; i++)
554 data[i] = devpriv->ao_readback[chan];
559 /* DIO devices are slightly special. Although it is possible to
560 * implement the insn_read/insn_write interface, it is much more
561 * useful to applications if you implement the insn_bits interface.
562 * This allows packed reading/writing of the DIO channels. The
563 * comedi core can convert between insn_bits and insn_read/write */
564 static int skel_dio_insn_bits(struct comedi_device *dev,
565 struct comedi_subdevice *s,
566 struct comedi_insn *insn, unsigned int *data)
571 /* The insn data is a mask in data[0] and the new data
572 * in data[1], each channel cooresponding to a bit. */
574 s->state &= ~data[0];
575 s->state |= data[0] & data[1];
576 /* Write out the new digital output lines */
577 /* outw(s->state,dev->iobase + SKEL_DIO); */
580 /* on return, data[1] contains the value of the digital
581 * input and output lines. */
582 /* data[1]=inw(dev->iobase + SKEL_DIO); */
583 /* or we could just return the software copy of the output values if
584 * it was a purely digital output subdevice */
585 /* data[1]=s->state; */
590 static int skel_dio_insn_config(struct comedi_device *dev,
591 struct comedi_subdevice *s,
592 struct comedi_insn *insn, unsigned int *data)
594 int chan = CR_CHAN(insn->chanspec);
596 /* The input or output configuration of each digital line is
597 * configured by a special insn_config instruction. chanspec
598 * contains the channel to be changed, and data[0] contains the
599 * value COMEDI_INPUT or COMEDI_OUTPUT. */
601 case INSN_CONFIG_DIO_OUTPUT:
602 s->io_bits |= 1 << chan;
604 case INSN_CONFIG_DIO_INPUT:
605 s->io_bits &= ~(1 << chan);
607 case INSN_CONFIG_DIO_QUERY:
609 (s->io_bits & (1 << chan)) ? COMEDI_OUTPUT : COMEDI_INPUT;
616 /* outw(s->io_bits,dev->iobase + SKEL_DIO_CONFIG); */
622 * A convenient macro that defines init_module() and cleanup_module(),
625 COMEDI_INITCLEANUP(driver_skel);
626 /* If you are writing a PCI driver you should use COMEDI_PCI_INITCLEANUP instead.
628 /* COMEDI_PCI_INITCLEANUP(driver_skel, skel_pci_table) */