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);
128 /* this structure is for data unique to this hardware driver. If
129 several hardware drivers keep similar information in this structure,
130 feel free to suggest moving the variable to the struct comedi_device struct.
132 struct skel_private {
136 /* would be useful for a PCI device */
137 struct pci_dev *pci_dev;
139 /* Used for AO readback */
140 unsigned int ao_readback[2];
144 * The struct comedi_driver structure tells the Comedi core module
145 * which functions to call to configure/deconfigure (attach/detach)
146 * the board, and also about the kernel module that contains
149 static int skel_attach(struct comedi_device *dev, struct comedi_devconfig *it);
150 static void skel_detach(struct comedi_device *dev);
151 static struct comedi_driver driver_skel = {
152 .driver_name = "dummy",
153 .module = THIS_MODULE,
154 .attach = skel_attach,
155 .detach = skel_detach,
156 /* It is not necessary to implement the following members if you are
157 * writing a driver for a ISA PnP or PCI card */
158 /* Most drivers will support multiple types of boards by
159 * having an array of board structures. These were defined
160 * in skel_boards[] above. Note that the element 'name'
161 * was first in the structure -- Comedi uses this fact to
162 * extract the name of the board without knowing any details
163 * about the structure except for its length.
164 * When a device is attached (by comedi_config), the name
165 * of the device is given to Comedi, and Comedi tries to
166 * match it by going through the list of board names. If
167 * there is a match, the address of the pointer is put
168 * into dev->board_ptr and driver->attach() is called.
170 * Note that these are not necessary if you can determine
171 * the type of board in software. ISA PnP, PCI, and PCMCIA
172 * devices are such boards.
174 .board_name = &skel_boards[0].name,
175 .offset = sizeof(struct skel_board),
176 .num_names = ARRAY_SIZE(skel_boards),
179 static int skel_ai_rinsn(struct comedi_device *dev, struct comedi_subdevice *s,
180 struct comedi_insn *insn, unsigned int *data);
181 static int skel_ao_winsn(struct comedi_device *dev, struct comedi_subdevice *s,
182 struct comedi_insn *insn, unsigned int *data);
183 static int skel_ao_rinsn(struct comedi_device *dev, struct comedi_subdevice *s,
184 struct comedi_insn *insn, unsigned int *data);
185 static int skel_dio_insn_bits(struct comedi_device *dev,
186 struct comedi_subdevice *s,
187 struct comedi_insn *insn, unsigned int *data);
188 static int skel_dio_insn_config(struct comedi_device *dev,
189 struct comedi_subdevice *s,
190 struct comedi_insn *insn, unsigned int *data);
191 static int skel_ai_cmdtest(struct comedi_device *dev,
192 struct comedi_subdevice *s, struct comedi_cmd *cmd);
193 static int skel_ns_to_timer(unsigned int *ns, int round);
196 * Attach is called by the Comedi core to configure the driver
197 * for a particular board. If you specified a board_name array
198 * in the driver structure, dev->board_ptr contains that
201 static int skel_attach(struct comedi_device *dev, struct comedi_devconfig *it)
203 const struct skel_board *thisboard;
204 struct skel_private *devpriv;
205 struct comedi_subdevice *s;
208 pr_info("comedi%d: skel: ", dev->minor);
211 * If you can probe the device to determine what device in a series
212 * it is, this is the place to do it. Otherwise, dev->board_ptr
213 * should already be initialized.
215 /* dev->board_ptr = skel_probe(dev, it); */
217 thisboard = comedi_board(dev);
219 * Initialize dev->board_name.
221 dev->board_name = thisboard->name;
223 /* Allocate the private data */
224 devpriv = kzalloc(sizeof(*devpriv), GFP_KERNEL);
227 dev->private = devpriv;
229 ret = comedi_alloc_subdevices(dev, 3);
233 s = &dev->subdevices[0];
234 /* dev->read_subdev=s; */
235 /* analog input subdevice */
236 s->type = COMEDI_SUBD_AI;
237 /* we support single-ended (ground) and differential */
238 s->subdev_flags = SDF_READABLE | SDF_GROUND | SDF_DIFF;
239 s->n_chan = thisboard->ai_chans;
240 s->maxdata = (1 << thisboard->ai_bits) - 1;
241 s->range_table = &range_bipolar10;
242 s->len_chanlist = 16; /* This is the maximum chanlist length that
243 the board can handle */
244 s->insn_read = skel_ai_rinsn;
246 * s->subdev_flags |= SDF_CMD_READ;
247 * s->do_cmd = skel_ai_cmd;
249 s->do_cmdtest = skel_ai_cmdtest;
251 s = &dev->subdevices[1];
252 /* analog output subdevice */
253 s->type = COMEDI_SUBD_AO;
254 s->subdev_flags = SDF_WRITABLE;
257 s->range_table = &range_bipolar5;
258 s->insn_write = skel_ao_winsn;
259 s->insn_read = skel_ao_rinsn;
261 s = &dev->subdevices[2];
262 /* digital i/o subdevice */
263 if (thisboard->have_dio) {
264 s->type = COMEDI_SUBD_DIO;
265 s->subdev_flags = SDF_READABLE | SDF_WRITABLE;
268 s->range_table = &range_digital;
269 s->insn_bits = skel_dio_insn_bits;
270 s->insn_config = skel_dio_insn_config;
272 s->type = COMEDI_SUBD_UNUSED;
275 pr_info("attached\n");
281 * _detach is called to deconfigure a device. It should deallocate
283 * This function is also called when _attach() fails, so it should be
284 * careful not to release resources that were not necessarily
285 * allocated by _attach(). dev->private and dev->subdevices are
286 * deallocated automatically by the core.
288 static void skel_detach(struct comedi_device *dev)
293 * "instructions" read/write data in "one-shot" or "software-triggered"
296 static int skel_ai_rinsn(struct comedi_device *dev, struct comedi_subdevice *s,
297 struct comedi_insn *insn, unsigned int *data)
299 const struct skel_board *thisboard = comedi_board(dev);
304 /* a typical programming sequence */
306 /* write channel to multiplexer */
307 /* outw(chan,dev->iobase + SKEL_MUX); */
309 /* don't wait for mux to settle */
311 /* convert n samples */
312 for (n = 0; n < insn->n; n++) {
313 /* trigger conversion */
314 /* outw(0,dev->iobase + SKEL_CONVERT); */
317 /* wait for conversion to end */
318 for (i = 0; i < TIMEOUT; i++) {
320 /* status = inb(dev->iobase + SKEL_STATUS); */
325 /* printk() should be used instead of printk()
326 * whenever the code can be called from real-time. */
327 pr_info("timeout\n");
332 /* d = inw(dev->iobase + SKEL_AI_DATA); */
335 /* mangle the data as necessary */
336 d ^= 1 << (thisboard->ai_bits - 1);
341 /* return the number of samples read/written */
346 * cmdtest tests a particular command to see if it is valid.
347 * Using the cmdtest ioctl, a user can create a valid cmd
348 * and then have it executes by the cmd ioctl.
350 * cmdtest returns 1,2,3,4 or 0, depending on which tests
351 * the command passes.
353 static int skel_ai_cmdtest(struct comedi_device *dev,
354 struct comedi_subdevice *s,
355 struct comedi_cmd *cmd)
360 /* Step 1 : check if triggers are trivially valid */
362 err |= cfc_check_trigger_src(&cmd->start_src, TRIG_NOW);
363 err |= cfc_check_trigger_src(&cmd->scan_begin_src,
364 TRIG_TIMER | TRIG_EXT);
365 err |= cfc_check_trigger_src(&cmd->convert_src, TRIG_TIMER | TRIG_EXT);
366 err |= cfc_check_trigger_src(&cmd->scan_end_src, TRIG_COUNT);
367 err |= cfc_check_trigger_src(&cmd->stop_src, TRIG_COUNT | TRIG_NONE);
372 /* Step 2a : make sure trigger sources are unique */
374 err |= cfc_check_trigger_is_unique(cmd->scan_begin_src);
375 err |= cfc_check_trigger_is_unique(cmd->convert_src);
376 err |= cfc_check_trigger_is_unique(cmd->stop_src);
378 /* Step 2b : and mutually compatible */
383 /* step 3: make sure arguments are trivially compatible */
385 if (cmd->start_arg != 0) {
389 #define MAX_SPEED 10000 /* in nanoseconds */
390 #define MIN_SPEED 1000000000 /* in nanoseconds */
392 if (cmd->scan_begin_src == TRIG_TIMER) {
393 if (cmd->scan_begin_arg < MAX_SPEED) {
394 cmd->scan_begin_arg = MAX_SPEED;
397 if (cmd->scan_begin_arg > MIN_SPEED) {
398 cmd->scan_begin_arg = MIN_SPEED;
402 /* external trigger */
403 /* should be level/edge, hi/lo specification here */
404 /* should specify multiple external triggers */
405 if (cmd->scan_begin_arg > 9) {
406 cmd->scan_begin_arg = 9;
410 if (cmd->convert_src == TRIG_TIMER) {
411 if (cmd->convert_arg < MAX_SPEED) {
412 cmd->convert_arg = MAX_SPEED;
415 if (cmd->convert_arg > MIN_SPEED) {
416 cmd->convert_arg = MIN_SPEED;
420 /* external trigger */
422 if (cmd->convert_arg > 9) {
423 cmd->convert_arg = 9;
428 if (cmd->scan_end_arg != cmd->chanlist_len) {
429 cmd->scan_end_arg = cmd->chanlist_len;
432 if (cmd->stop_src == TRIG_COUNT) {
433 if (cmd->stop_arg > 0x00ffffff) {
434 cmd->stop_arg = 0x00ffffff;
439 if (cmd->stop_arg != 0) {
448 /* step 4: fix up any arguments */
450 if (cmd->scan_begin_src == TRIG_TIMER) {
451 tmp = cmd->scan_begin_arg;
452 skel_ns_to_timer(&cmd->scan_begin_arg,
453 cmd->flags & TRIG_ROUND_MASK);
454 if (tmp != cmd->scan_begin_arg)
457 if (cmd->convert_src == TRIG_TIMER) {
458 tmp = cmd->convert_arg;
459 skel_ns_to_timer(&cmd->convert_arg,
460 cmd->flags & TRIG_ROUND_MASK);
461 if (tmp != cmd->convert_arg)
463 if (cmd->scan_begin_src == TRIG_TIMER &&
464 cmd->scan_begin_arg <
465 cmd->convert_arg * cmd->scan_end_arg) {
466 cmd->scan_begin_arg =
467 cmd->convert_arg * cmd->scan_end_arg;
478 /* This function doesn't require a particular form, this is just
479 * what happens to be used in some of the drivers. It should
480 * convert ns nanoseconds to a counter value suitable for programming
481 * the device. Also, it should adjust ns so that it cooresponds to
482 * the actual time that the device will use. */
483 static int skel_ns_to_timer(unsigned int *ns, int round)
486 /* if your timing is done through two cascaded timers, the
487 * i8253_cascade_ns_to_timer() function in 8253.h can be
488 * very helpful. There are also i8254_load() and i8254_mm_load()
489 * which can be used to load values into the ubiquitous 8254 counters
495 static int skel_ao_winsn(struct comedi_device *dev, struct comedi_subdevice *s,
496 struct comedi_insn *insn, unsigned int *data)
498 struct skel_private *devpriv = dev->private;
500 int chan = CR_CHAN(insn->chanspec);
502 pr_info("skel_ao_winsn\n");
503 /* Writing a list of values to an AO channel is probably not
504 * very useful, but that's how the interface is defined. */
505 for (i = 0; i < insn->n; i++) {
506 /* a typical programming sequence */
507 /* outw(data[i],dev->iobase + SKEL_DA0 + chan); */
508 devpriv->ao_readback[chan] = data[i];
511 /* return the number of samples read/written */
515 /* AO subdevices should have a read insn as well as a write insn.
516 * Usually this means copying a value stored in devpriv. */
517 static int skel_ao_rinsn(struct comedi_device *dev, struct comedi_subdevice *s,
518 struct comedi_insn *insn, unsigned int *data)
520 struct skel_private *devpriv = dev->private;
522 int chan = CR_CHAN(insn->chanspec);
524 for (i = 0; i < insn->n; i++)
525 data[i] = devpriv->ao_readback[chan];
530 /* DIO devices are slightly special. Although it is possible to
531 * implement the insn_read/insn_write interface, it is much more
532 * useful to applications if you implement the insn_bits interface.
533 * This allows packed reading/writing of the DIO channels. The
534 * comedi core can convert between insn_bits and insn_read/write */
535 static int skel_dio_insn_bits(struct comedi_device *dev,
536 struct comedi_subdevice *s,
537 struct comedi_insn *insn, unsigned int *data)
539 /* The insn data is a mask in data[0] and the new data
540 * in data[1], each channel cooresponding to a bit. */
542 s->state &= ~data[0];
543 s->state |= data[0] & data[1];
544 /* Write out the new digital output lines */
545 /* outw(s->state,dev->iobase + SKEL_DIO); */
548 /* on return, data[1] contains the value of the digital
549 * input and output lines. */
550 /* data[1]=inw(dev->iobase + SKEL_DIO); */
551 /* or we could just return the software copy of the output values if
552 * it was a purely digital output subdevice */
553 /* data[1]=s->state; */
558 static int skel_dio_insn_config(struct comedi_device *dev,
559 struct comedi_subdevice *s,
560 struct comedi_insn *insn, unsigned int *data)
562 int chan = CR_CHAN(insn->chanspec);
564 /* The input or output configuration of each digital line is
565 * configured by a special insn_config instruction. chanspec
566 * contains the channel to be changed, and data[0] contains the
567 * value COMEDI_INPUT or COMEDI_OUTPUT. */
569 case INSN_CONFIG_DIO_OUTPUT:
570 s->io_bits |= 1 << chan;
572 case INSN_CONFIG_DIO_INPUT:
573 s->io_bits &= ~(1 << chan);
575 case INSN_CONFIG_DIO_QUERY:
577 (s->io_bits & (1 << chan)) ? COMEDI_OUTPUT : COMEDI_INPUT;
584 /* outw(s->io_bits,dev->iobase + SKEL_DIO_CONFIG); */
589 #ifdef CONFIG_COMEDI_PCI_DRIVERS
590 static int __devinit driver_skel_pci_probe(struct pci_dev *dev,
591 const struct pci_device_id *ent)
593 return comedi_pci_auto_config(dev, &driver_skel);
596 static void __devexit driver_skel_pci_remove(struct pci_dev *dev)
598 comedi_pci_auto_unconfig(dev);
601 static struct pci_driver driver_skel_pci_driver = {
602 .id_table = skel_pci_table,
603 .probe = &driver_skel_pci_probe,
604 .remove = __devexit_p(&driver_skel_pci_remove)
607 static int __init driver_skel_init_module(void)
611 retval = comedi_driver_register(&driver_skel);
615 driver_skel_pci_driver.name = (char *)driver_skel.driver_name;
616 return pci_register_driver(&driver_skel_pci_driver);
619 static void __exit driver_skel_cleanup_module(void)
621 pci_unregister_driver(&driver_skel_pci_driver);
622 comedi_driver_unregister(&driver_skel);
625 module_init(driver_skel_init_module);
626 module_exit(driver_skel_cleanup_module);
628 module_comedi_driver(driver_skel);
631 MODULE_AUTHOR("Comedi http://www.comedi.org");
632 MODULE_DESCRIPTION("Comedi low-level driver");
633 MODULE_LICENSE("GPL");