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 #include "comedi_fc.h"
81 /* Imaginary registers for the imaginary board */
85 #define SKEL_START_AI_CONV 0
86 #define SKEL_AI_READ 0
89 * Board descriptions for two imaginary boards. Describing the
90 * boards in this way is optional, and completely driver-dependent.
91 * Some drivers use arrays such as this, other do not.
100 static const struct skel_board skel_boards[] = {
115 /* This is used by modprobe to translate PCI IDs to drivers. Should
116 * only be used for PCI and ISA-PnP devices */
117 /* Please add your PCI vendor ID to comedidev.h, and it will be forwarded
119 #define PCI_VENDOR_ID_SKEL 0xdafe
120 static DEFINE_PCI_DEVICE_TABLE(skel_pci_table) = {
121 { PCI_DEVICE(PCI_VENDOR_ID_SKEL, 0x0100) },
122 { PCI_DEVICE(PCI_VENDOR_ID_SKEL, 0x0200) },
126 MODULE_DEVICE_TABLE(pci, skel_pci_table);
129 * Useful for shorthand access to the particular board structure
131 #define thisboard ((const struct skel_board *)dev->board_ptr)
133 /* this structure is for data unique to this hardware driver. If
134 several hardware drivers keep similar information in this structure,
135 feel free to suggest moving the variable to the struct comedi_device struct.
137 struct skel_private {
141 /* would be useful for a PCI device */
142 struct pci_dev *pci_dev;
144 /* Used for AO readback */
145 unsigned int ao_readback[2];
149 * The struct comedi_driver structure tells the Comedi core module
150 * which functions to call to configure/deconfigure (attach/detach)
151 * the board, and also about the kernel module that contains
154 static int skel_attach(struct comedi_device *dev, struct comedi_devconfig *it);
155 static void skel_detach(struct comedi_device *dev);
156 static struct comedi_driver driver_skel = {
157 .driver_name = "dummy",
158 .module = THIS_MODULE,
159 .attach = skel_attach,
160 .detach = skel_detach,
161 /* It is not necessary to implement the following members if you are
162 * writing a driver for a ISA PnP or PCI card */
163 /* Most drivers will support multiple types of boards by
164 * having an array of board structures. These were defined
165 * in skel_boards[] above. Note that the element 'name'
166 * was first in the structure -- Comedi uses this fact to
167 * extract the name of the board without knowing any details
168 * about the structure except for its length.
169 * When a device is attached (by comedi_config), the name
170 * of the device is given to Comedi, and Comedi tries to
171 * match it by going through the list of board names. If
172 * there is a match, the address of the pointer is put
173 * into dev->board_ptr and driver->attach() is called.
175 * Note that these are not necessary if you can determine
176 * the type of board in software. ISA PnP, PCI, and PCMCIA
177 * devices are such boards.
179 .board_name = &skel_boards[0].name,
180 .offset = sizeof(struct skel_board),
181 .num_names = ARRAY_SIZE(skel_boards),
184 static int skel_ai_rinsn(struct comedi_device *dev, struct comedi_subdevice *s,
185 struct comedi_insn *insn, unsigned int *data);
186 static int skel_ao_winsn(struct comedi_device *dev, struct comedi_subdevice *s,
187 struct comedi_insn *insn, unsigned int *data);
188 static int skel_ao_rinsn(struct comedi_device *dev, struct comedi_subdevice *s,
189 struct comedi_insn *insn, unsigned int *data);
190 static int skel_dio_insn_bits(struct comedi_device *dev,
191 struct comedi_subdevice *s,
192 struct comedi_insn *insn, unsigned int *data);
193 static int skel_dio_insn_config(struct comedi_device *dev,
194 struct comedi_subdevice *s,
195 struct comedi_insn *insn, unsigned int *data);
196 static int skel_ai_cmdtest(struct comedi_device *dev,
197 struct comedi_subdevice *s, struct comedi_cmd *cmd);
198 static int skel_ns_to_timer(unsigned int *ns, int round);
201 * Attach is called by the Comedi core to configure the driver
202 * for a particular board. If you specified a board_name array
203 * in the driver structure, dev->board_ptr contains that
206 static int skel_attach(struct comedi_device *dev, struct comedi_devconfig *it)
208 struct skel_private *devpriv;
209 struct comedi_subdevice *s;
212 pr_info("comedi%d: skel: ", dev->minor);
215 * If you can probe the device to determine what device in a series
216 * it is, this is the place to do it. Otherwise, dev->board_ptr
217 * should already be initialized.
219 /* dev->board_ptr = skel_probe(dev, it); */
222 * Initialize dev->board_name. Note that we can use the "thisboard"
223 * macro now, since we just initialized it in the last line.
225 dev->board_name = thisboard->name;
227 /* Allocate the private data */
228 devpriv = kzalloc(sizeof(*devpriv), GFP_KERNEL);
231 dev->private = devpriv;
233 ret = comedi_alloc_subdevices(dev, 3);
237 s = &dev->subdevices[0];
238 /* dev->read_subdev=s; */
239 /* analog input subdevice */
240 s->type = COMEDI_SUBD_AI;
241 /* we support single-ended (ground) and differential */
242 s->subdev_flags = SDF_READABLE | SDF_GROUND | SDF_DIFF;
243 s->n_chan = thisboard->ai_chans;
244 s->maxdata = (1 << thisboard->ai_bits) - 1;
245 s->range_table = &range_bipolar10;
246 s->len_chanlist = 16; /* This is the maximum chanlist length that
247 the board can handle */
248 s->insn_read = skel_ai_rinsn;
250 * s->subdev_flags |= SDF_CMD_READ;
251 * s->do_cmd = skel_ai_cmd;
253 s->do_cmdtest = skel_ai_cmdtest;
255 s = &dev->subdevices[1];
256 /* analog output subdevice */
257 s->type = COMEDI_SUBD_AO;
258 s->subdev_flags = SDF_WRITABLE;
261 s->range_table = &range_bipolar5;
262 s->insn_write = skel_ao_winsn;
263 s->insn_read = skel_ao_rinsn;
265 s = &dev->subdevices[2];
266 /* digital i/o subdevice */
267 if (thisboard->have_dio) {
268 s->type = COMEDI_SUBD_DIO;
269 s->subdev_flags = SDF_READABLE | SDF_WRITABLE;
272 s->range_table = &range_digital;
273 s->insn_bits = skel_dio_insn_bits;
274 s->insn_config = skel_dio_insn_config;
276 s->type = COMEDI_SUBD_UNUSED;
279 pr_info("attached\n");
285 * _detach is called to deconfigure a device. It should deallocate
287 * This function is also called when _attach() fails, so it should be
288 * careful not to release resources that were not necessarily
289 * allocated by _attach(). dev->private and dev->subdevices are
290 * deallocated automatically by the core.
292 static void skel_detach(struct comedi_device *dev)
297 * "instructions" read/write data in "one-shot" or "software-triggered"
300 static int skel_ai_rinsn(struct comedi_device *dev, struct comedi_subdevice *s,
301 struct comedi_insn *insn, unsigned int *data)
307 /* a typical programming sequence */
309 /* write channel to multiplexer */
310 /* outw(chan,dev->iobase + SKEL_MUX); */
312 /* don't wait for mux to settle */
314 /* convert n samples */
315 for (n = 0; n < insn->n; n++) {
316 /* trigger conversion */
317 /* outw(0,dev->iobase + SKEL_CONVERT); */
320 /* wait for conversion to end */
321 for (i = 0; i < TIMEOUT; i++) {
323 /* status = inb(dev->iobase + SKEL_STATUS); */
328 /* printk() should be used instead of printk()
329 * whenever the code can be called from real-time. */
330 pr_info("timeout\n");
335 /* d = inw(dev->iobase + SKEL_AI_DATA); */
338 /* mangle the data as necessary */
339 d ^= 1 << (thisboard->ai_bits - 1);
344 /* return the number of samples read/written */
349 * cmdtest tests a particular command to see if it is valid.
350 * Using the cmdtest ioctl, a user can create a valid cmd
351 * and then have it executes by the cmd ioctl.
353 * cmdtest returns 1,2,3,4 or 0, depending on which tests
354 * the command passes.
356 static int skel_ai_cmdtest(struct comedi_device *dev,
357 struct comedi_subdevice *s,
358 struct comedi_cmd *cmd)
363 /* Step 1 : check if triggers are trivially valid */
365 err |= cfc_check_trigger_src(&cmd->start_src, TRIG_NOW);
366 err |= cfc_check_trigger_src(&cmd->scan_begin_src,
367 TRIG_TIMER | TRIG_EXT);
368 err |= cfc_check_trigger_src(&cmd->convert_src, TRIG_TIMER | TRIG_EXT);
369 err |= cfc_check_trigger_src(&cmd->scan_end_src, TRIG_COUNT);
370 err |= cfc_check_trigger_src(&cmd->stop_src, TRIG_COUNT | TRIG_NONE);
375 /* Step 2a : make sure trigger sources are unique */
377 err |= cfc_check_trigger_is_unique(cmd->scan_begin_src);
378 err |= cfc_check_trigger_is_unique(cmd->convert_src);
379 err |= cfc_check_trigger_is_unique(cmd->stop_src);
381 /* Step 2b : and mutually compatible */
386 /* step 3: make sure arguments are trivially compatible */
388 if (cmd->start_arg != 0) {
392 #define MAX_SPEED 10000 /* in nanoseconds */
393 #define MIN_SPEED 1000000000 /* in nanoseconds */
395 if (cmd->scan_begin_src == TRIG_TIMER) {
396 if (cmd->scan_begin_arg < MAX_SPEED) {
397 cmd->scan_begin_arg = MAX_SPEED;
400 if (cmd->scan_begin_arg > MIN_SPEED) {
401 cmd->scan_begin_arg = MIN_SPEED;
405 /* external trigger */
406 /* should be level/edge, hi/lo specification here */
407 /* should specify multiple external triggers */
408 if (cmd->scan_begin_arg > 9) {
409 cmd->scan_begin_arg = 9;
413 if (cmd->convert_src == TRIG_TIMER) {
414 if (cmd->convert_arg < MAX_SPEED) {
415 cmd->convert_arg = MAX_SPEED;
418 if (cmd->convert_arg > MIN_SPEED) {
419 cmd->convert_arg = MIN_SPEED;
423 /* external trigger */
425 if (cmd->convert_arg > 9) {
426 cmd->convert_arg = 9;
431 if (cmd->scan_end_arg != cmd->chanlist_len) {
432 cmd->scan_end_arg = cmd->chanlist_len;
435 if (cmd->stop_src == TRIG_COUNT) {
436 if (cmd->stop_arg > 0x00ffffff) {
437 cmd->stop_arg = 0x00ffffff;
442 if (cmd->stop_arg != 0) {
451 /* step 4: fix up any arguments */
453 if (cmd->scan_begin_src == TRIG_TIMER) {
454 tmp = cmd->scan_begin_arg;
455 skel_ns_to_timer(&cmd->scan_begin_arg,
456 cmd->flags & TRIG_ROUND_MASK);
457 if (tmp != cmd->scan_begin_arg)
460 if (cmd->convert_src == TRIG_TIMER) {
461 tmp = cmd->convert_arg;
462 skel_ns_to_timer(&cmd->convert_arg,
463 cmd->flags & TRIG_ROUND_MASK);
464 if (tmp != cmd->convert_arg)
466 if (cmd->scan_begin_src == TRIG_TIMER &&
467 cmd->scan_begin_arg <
468 cmd->convert_arg * cmd->scan_end_arg) {
469 cmd->scan_begin_arg =
470 cmd->convert_arg * cmd->scan_end_arg;
481 /* This function doesn't require a particular form, this is just
482 * what happens to be used in some of the drivers. It should
483 * convert ns nanoseconds to a counter value suitable for programming
484 * the device. Also, it should adjust ns so that it cooresponds to
485 * the actual time that the device will use. */
486 static int skel_ns_to_timer(unsigned int *ns, int round)
489 /* if your timing is done through two cascaded timers, the
490 * i8253_cascade_ns_to_timer() function in 8253.h can be
491 * very helpful. There are also i8254_load() and i8254_mm_load()
492 * which can be used to load values into the ubiquitous 8254 counters
498 static int skel_ao_winsn(struct comedi_device *dev, struct comedi_subdevice *s,
499 struct comedi_insn *insn, unsigned int *data)
501 struct skel_private *devpriv = dev->private;
503 int chan = CR_CHAN(insn->chanspec);
505 pr_info("skel_ao_winsn\n");
506 /* Writing a list of values to an AO channel is probably not
507 * very useful, but that's how the interface is defined. */
508 for (i = 0; i < insn->n; i++) {
509 /* a typical programming sequence */
510 /* outw(data[i],dev->iobase + SKEL_DA0 + chan); */
511 devpriv->ao_readback[chan] = data[i];
514 /* return the number of samples read/written */
518 /* AO subdevices should have a read insn as well as a write insn.
519 * Usually this means copying a value stored in devpriv. */
520 static int skel_ao_rinsn(struct comedi_device *dev, struct comedi_subdevice *s,
521 struct comedi_insn *insn, unsigned int *data)
523 struct skel_private *devpriv = dev->private;
525 int chan = CR_CHAN(insn->chanspec);
527 for (i = 0; i < insn->n; i++)
528 data[i] = devpriv->ao_readback[chan];
533 /* DIO devices are slightly special. Although it is possible to
534 * implement the insn_read/insn_write interface, it is much more
535 * useful to applications if you implement the insn_bits interface.
536 * This allows packed reading/writing of the DIO channels. The
537 * comedi core can convert between insn_bits and insn_read/write */
538 static int skel_dio_insn_bits(struct comedi_device *dev,
539 struct comedi_subdevice *s,
540 struct comedi_insn *insn, unsigned int *data)
542 /* The insn data is a mask in data[0] and the new data
543 * in data[1], each channel cooresponding to a bit. */
545 s->state &= ~data[0];
546 s->state |= data[0] & data[1];
547 /* Write out the new digital output lines */
548 /* outw(s->state,dev->iobase + SKEL_DIO); */
551 /* on return, data[1] contains the value of the digital
552 * input and output lines. */
553 /* data[1]=inw(dev->iobase + SKEL_DIO); */
554 /* or we could just return the software copy of the output values if
555 * it was a purely digital output subdevice */
556 /* data[1]=s->state; */
561 static int skel_dio_insn_config(struct comedi_device *dev,
562 struct comedi_subdevice *s,
563 struct comedi_insn *insn, unsigned int *data)
565 int chan = CR_CHAN(insn->chanspec);
567 /* The input or output configuration of each digital line is
568 * configured by a special insn_config instruction. chanspec
569 * contains the channel to be changed, and data[0] contains the
570 * value COMEDI_INPUT or COMEDI_OUTPUT. */
572 case INSN_CONFIG_DIO_OUTPUT:
573 s->io_bits |= 1 << chan;
575 case INSN_CONFIG_DIO_INPUT:
576 s->io_bits &= ~(1 << chan);
578 case INSN_CONFIG_DIO_QUERY:
580 (s->io_bits & (1 << chan)) ? COMEDI_OUTPUT : COMEDI_INPUT;
587 /* outw(s->io_bits,dev->iobase + SKEL_DIO_CONFIG); */
592 #ifdef CONFIG_COMEDI_PCI_DRIVERS
593 static int __devinit driver_skel_pci_probe(struct pci_dev *dev,
594 const struct pci_device_id *ent)
596 return comedi_pci_auto_config(dev, &driver_skel);
599 static void __devexit driver_skel_pci_remove(struct pci_dev *dev)
601 comedi_pci_auto_unconfig(dev);
604 static struct pci_driver driver_skel_pci_driver = {
605 .id_table = skel_pci_table,
606 .probe = &driver_skel_pci_probe,
607 .remove = __devexit_p(&driver_skel_pci_remove)
610 static int __init driver_skel_init_module(void)
614 retval = comedi_driver_register(&driver_skel);
618 driver_skel_pci_driver.name = (char *)driver_skel.driver_name;
619 return pci_register_driver(&driver_skel_pci_driver);
622 static void __exit driver_skel_cleanup_module(void)
624 pci_unregister_driver(&driver_skel_pci_driver);
625 comedi_driver_unregister(&driver_skel);
628 module_init(driver_skel_init_module);
629 module_exit(driver_skel_cleanup_module);
631 static int __init driver_skel_init_module(void)
633 return comedi_driver_register(&driver_skel);
636 static void __exit driver_skel_cleanup_module(void)
638 comedi_driver_unregister(&driver_skel);
641 module_init(driver_skel_init_module);
642 module_exit(driver_skel_cleanup_module);
645 MODULE_AUTHOR("Comedi http://www.comedi.org");
646 MODULE_DESCRIPTION("Comedi low-level driver");
647 MODULE_LICENSE("GPL");