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 * most drivers define the following macro to make it easy to
150 * access the private structure.
152 #define devpriv ((struct skel_private *)dev->private)
155 * The struct comedi_driver structure tells the Comedi core module
156 * which functions to call to configure/deconfigure (attach/detach)
157 * the board, and also about the kernel module that contains
160 static int skel_attach(struct comedi_device
*dev
, struct comedi_devconfig
*it
);
161 static void skel_detach(struct comedi_device
*dev
);
162 static struct comedi_driver driver_skel
= {
163 .driver_name
= "dummy",
164 .module
= THIS_MODULE
,
165 .attach
= skel_attach
,
166 .detach
= skel_detach
,
167 /* It is not necessary to implement the following members if you are
168 * writing a driver for a ISA PnP or PCI card */
169 /* Most drivers will support multiple types of boards by
170 * having an array of board structures. These were defined
171 * in skel_boards[] above. Note that the element 'name'
172 * was first in the structure -- Comedi uses this fact to
173 * extract the name of the board without knowing any details
174 * about the structure except for its length.
175 * When a device is attached (by comedi_config), the name
176 * of the device is given to Comedi, and Comedi tries to
177 * match it by going through the list of board names. If
178 * there is a match, the address of the pointer is put
179 * into dev->board_ptr and driver->attach() is called.
181 * Note that these are not necessary if you can determine
182 * the type of board in software. ISA PnP, PCI, and PCMCIA
183 * devices are such boards.
185 .board_name
= &skel_boards
[0].name
,
186 .offset
= sizeof(struct skel_board
),
187 .num_names
= ARRAY_SIZE(skel_boards
),
190 static int skel_ai_rinsn(struct comedi_device
*dev
, struct comedi_subdevice
*s
,
191 struct comedi_insn
*insn
, unsigned int *data
);
192 static int skel_ao_winsn(struct comedi_device
*dev
, struct comedi_subdevice
*s
,
193 struct comedi_insn
*insn
, unsigned int *data
);
194 static int skel_ao_rinsn(struct comedi_device
*dev
, struct comedi_subdevice
*s
,
195 struct comedi_insn
*insn
, unsigned int *data
);
196 static int skel_dio_insn_bits(struct comedi_device
*dev
,
197 struct comedi_subdevice
*s
,
198 struct comedi_insn
*insn
, unsigned int *data
);
199 static int skel_dio_insn_config(struct comedi_device
*dev
,
200 struct comedi_subdevice
*s
,
201 struct comedi_insn
*insn
, unsigned int *data
);
202 static int skel_ai_cmdtest(struct comedi_device
*dev
,
203 struct comedi_subdevice
*s
, struct comedi_cmd
*cmd
);
204 static int skel_ns_to_timer(unsigned int *ns
, int round
);
207 * Attach is called by the Comedi core to configure the driver
208 * for a particular board. If you specified a board_name array
209 * in the driver structure, dev->board_ptr contains that
212 static int skel_attach(struct comedi_device
*dev
, struct comedi_devconfig
*it
)
214 struct comedi_subdevice
*s
;
217 pr_info("comedi%d: skel: ", dev
->minor
);
220 * If you can probe the device to determine what device in a series
221 * it is, this is the place to do it. Otherwise, dev->board_ptr
222 * should already be initialized.
224 /* dev->board_ptr = skel_probe(dev, it); */
227 * Initialize dev->board_name. Note that we can use the "thisboard"
228 * macro now, since we just initialized it in the last line.
230 dev
->board_name
= thisboard
->name
;
233 * Allocate the private structure area. alloc_private() is a
234 * convenient macro defined in comedidev.h.
236 if (alloc_private(dev
, sizeof(struct skel_private
)) < 0)
239 ret
= comedi_alloc_subdevices(dev
, 3);
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 pr_info("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 void skel_detach(struct comedi_device
*dev
)
303 * "instructions" read/write data in "one-shot" or "software-triggered"
306 static int skel_ai_rinsn(struct comedi_device
*dev
, struct comedi_subdevice
*s
,
307 struct comedi_insn
*insn
, unsigned int *data
)
313 /* a typical programming sequence */
315 /* write channel to multiplexer */
316 /* outw(chan,dev->iobase + SKEL_MUX); */
318 /* don't wait for mux to settle */
320 /* convert n samples */
321 for (n
= 0; n
< insn
->n
; n
++) {
322 /* trigger conversion */
323 /* outw(0,dev->iobase + SKEL_CONVERT); */
326 /* wait for conversion to end */
327 for (i
= 0; i
< TIMEOUT
; i
++) {
329 /* status = inb(dev->iobase + SKEL_STATUS); */
334 /* printk() should be used instead of printk()
335 * whenever the code can be called from real-time. */
336 pr_info("timeout\n");
341 /* d = inw(dev->iobase + SKEL_AI_DATA); */
344 /* mangle the data as necessary */
345 d
^= 1 << (thisboard
->ai_bits
- 1);
350 /* return the number of samples read/written */
355 * cmdtest tests a particular command to see if it is valid.
356 * Using the cmdtest ioctl, a user can create a valid cmd
357 * and then have it executes by the cmd ioctl.
359 * cmdtest returns 1,2,3,4 or 0, depending on which tests
360 * the command passes.
362 static int skel_ai_cmdtest(struct comedi_device
*dev
,
363 struct comedi_subdevice
*s
,
364 struct comedi_cmd
*cmd
)
369 /* Step 1 : check if triggers are trivially valid */
371 err
|= cfc_check_trigger_src(&cmd
->start_src
, TRIG_NOW
);
372 err
|= cfc_check_trigger_src(&cmd
->scan_begin_src
,
373 TRIG_TIMER
| TRIG_EXT
);
374 err
|= cfc_check_trigger_src(&cmd
->convert_src
, TRIG_TIMER
| TRIG_EXT
);
375 err
|= cfc_check_trigger_src(&cmd
->scan_end_src
, TRIG_COUNT
);
376 err
|= cfc_check_trigger_src(&cmd
->stop_src
, TRIG_COUNT
| TRIG_NONE
);
381 /* Step 2a : make sure trigger sources are unique */
383 err
|= cfc_check_trigger_is_unique(cmd
->scan_begin_src
);
384 err
|= cfc_check_trigger_is_unique(cmd
->convert_src
);
385 err
|= cfc_check_trigger_is_unique(cmd
->stop_src
);
387 /* Step 2b : and mutually compatible */
392 /* step 3: make sure arguments are trivially compatible */
394 if (cmd
->start_arg
!= 0) {
398 #define MAX_SPEED 10000 /* in nanoseconds */
399 #define MIN_SPEED 1000000000 /* in nanoseconds */
401 if (cmd
->scan_begin_src
== TRIG_TIMER
) {
402 if (cmd
->scan_begin_arg
< MAX_SPEED
) {
403 cmd
->scan_begin_arg
= MAX_SPEED
;
406 if (cmd
->scan_begin_arg
> MIN_SPEED
) {
407 cmd
->scan_begin_arg
= MIN_SPEED
;
411 /* external trigger */
412 /* should be level/edge, hi/lo specification here */
413 /* should specify multiple external triggers */
414 if (cmd
->scan_begin_arg
> 9) {
415 cmd
->scan_begin_arg
= 9;
419 if (cmd
->convert_src
== TRIG_TIMER
) {
420 if (cmd
->convert_arg
< MAX_SPEED
) {
421 cmd
->convert_arg
= MAX_SPEED
;
424 if (cmd
->convert_arg
> MIN_SPEED
) {
425 cmd
->convert_arg
= MIN_SPEED
;
429 /* external trigger */
431 if (cmd
->convert_arg
> 9) {
432 cmd
->convert_arg
= 9;
437 if (cmd
->scan_end_arg
!= cmd
->chanlist_len
) {
438 cmd
->scan_end_arg
= cmd
->chanlist_len
;
441 if (cmd
->stop_src
== TRIG_COUNT
) {
442 if (cmd
->stop_arg
> 0x00ffffff) {
443 cmd
->stop_arg
= 0x00ffffff;
448 if (cmd
->stop_arg
!= 0) {
457 /* step 4: fix up any arguments */
459 if (cmd
->scan_begin_src
== TRIG_TIMER
) {
460 tmp
= cmd
->scan_begin_arg
;
461 skel_ns_to_timer(&cmd
->scan_begin_arg
,
462 cmd
->flags
& TRIG_ROUND_MASK
);
463 if (tmp
!= cmd
->scan_begin_arg
)
466 if (cmd
->convert_src
== TRIG_TIMER
) {
467 tmp
= cmd
->convert_arg
;
468 skel_ns_to_timer(&cmd
->convert_arg
,
469 cmd
->flags
& TRIG_ROUND_MASK
);
470 if (tmp
!= cmd
->convert_arg
)
472 if (cmd
->scan_begin_src
== TRIG_TIMER
&&
473 cmd
->scan_begin_arg
<
474 cmd
->convert_arg
* cmd
->scan_end_arg
) {
475 cmd
->scan_begin_arg
=
476 cmd
->convert_arg
* cmd
->scan_end_arg
;
487 /* This function doesn't require a particular form, this is just
488 * what happens to be used in some of the drivers. It should
489 * convert ns nanoseconds to a counter value suitable for programming
490 * the device. Also, it should adjust ns so that it cooresponds to
491 * the actual time that the device will use. */
492 static int skel_ns_to_timer(unsigned int *ns
, int round
)
495 /* if your timing is done through two cascaded timers, the
496 * i8253_cascade_ns_to_timer() function in 8253.h can be
497 * very helpful. There are also i8254_load() and i8254_mm_load()
498 * which can be used to load values into the ubiquitous 8254 counters
504 static int skel_ao_winsn(struct comedi_device
*dev
, struct comedi_subdevice
*s
,
505 struct comedi_insn
*insn
, unsigned int *data
)
508 int chan
= CR_CHAN(insn
->chanspec
);
510 pr_info("skel_ao_winsn\n");
511 /* Writing a list of values to an AO channel is probably not
512 * very useful, but that's how the interface is defined. */
513 for (i
= 0; i
< insn
->n
; i
++) {
514 /* a typical programming sequence */
515 /* outw(data[i],dev->iobase + SKEL_DA0 + chan); */
516 devpriv
->ao_readback
[chan
] = data
[i
];
519 /* return the number of samples read/written */
523 /* AO subdevices should have a read insn as well as a write insn.
524 * Usually this means copying a value stored in devpriv. */
525 static int skel_ao_rinsn(struct comedi_device
*dev
, struct comedi_subdevice
*s
,
526 struct comedi_insn
*insn
, unsigned int *data
)
529 int chan
= CR_CHAN(insn
->chanspec
);
531 for (i
= 0; i
< insn
->n
; i
++)
532 data
[i
] = devpriv
->ao_readback
[chan
];
537 /* DIO devices are slightly special. Although it is possible to
538 * implement the insn_read/insn_write interface, it is much more
539 * useful to applications if you implement the insn_bits interface.
540 * This allows packed reading/writing of the DIO channels. The
541 * comedi core can convert between insn_bits and insn_read/write */
542 static int skel_dio_insn_bits(struct comedi_device
*dev
,
543 struct comedi_subdevice
*s
,
544 struct comedi_insn
*insn
, unsigned int *data
)
546 /* The insn data is a mask in data[0] and the new data
547 * in data[1], each channel cooresponding to a bit. */
549 s
->state
&= ~data
[0];
550 s
->state
|= data
[0] & data
[1];
551 /* Write out the new digital output lines */
552 /* outw(s->state,dev->iobase + SKEL_DIO); */
555 /* on return, data[1] contains the value of the digital
556 * input and output lines. */
557 /* data[1]=inw(dev->iobase + SKEL_DIO); */
558 /* or we could just return the software copy of the output values if
559 * it was a purely digital output subdevice */
560 /* data[1]=s->state; */
565 static int skel_dio_insn_config(struct comedi_device
*dev
,
566 struct comedi_subdevice
*s
,
567 struct comedi_insn
*insn
, unsigned int *data
)
569 int chan
= CR_CHAN(insn
->chanspec
);
571 /* The input or output configuration of each digital line is
572 * configured by a special insn_config instruction. chanspec
573 * contains the channel to be changed, and data[0] contains the
574 * value COMEDI_INPUT or COMEDI_OUTPUT. */
576 case INSN_CONFIG_DIO_OUTPUT
:
577 s
->io_bits
|= 1 << chan
;
579 case INSN_CONFIG_DIO_INPUT
:
580 s
->io_bits
&= ~(1 << chan
);
582 case INSN_CONFIG_DIO_QUERY
:
584 (s
->io_bits
& (1 << chan
)) ? COMEDI_OUTPUT
: COMEDI_INPUT
;
591 /* outw(s->io_bits,dev->iobase + SKEL_DIO_CONFIG); */
596 #ifdef CONFIG_COMEDI_PCI_DRIVERS
597 static int __devinit
driver_skel_pci_probe(struct pci_dev
*dev
,
598 const struct pci_device_id
*ent
)
600 return comedi_pci_auto_config(dev
, &driver_skel
);
603 static void __devexit
driver_skel_pci_remove(struct pci_dev
*dev
)
605 comedi_pci_auto_unconfig(dev
);
608 static struct pci_driver driver_skel_pci_driver
= {
609 .id_table
= skel_pci_table
,
610 .probe
= &driver_skel_pci_probe
,
611 .remove
= __devexit_p(&driver_skel_pci_remove
)
614 static int __init
driver_skel_init_module(void)
618 retval
= comedi_driver_register(&driver_skel
);
622 driver_skel_pci_driver
.name
= (char *)driver_skel
.driver_name
;
623 return pci_register_driver(&driver_skel_pci_driver
);
626 static void __exit
driver_skel_cleanup_module(void)
628 pci_unregister_driver(&driver_skel_pci_driver
);
629 comedi_driver_unregister(&driver_skel
);
632 module_init(driver_skel_init_module
);
633 module_exit(driver_skel_cleanup_module
);
635 static int __init
driver_skel_init_module(void)
637 return comedi_driver_register(&driver_skel
);
640 static void __exit
driver_skel_cleanup_module(void)
642 comedi_driver_unregister(&driver_skel
);
645 module_init(driver_skel_init_module
);
646 module_exit(driver_skel_cleanup_module
);
649 MODULE_AUTHOR("Comedi http://www.comedi.org");
650 MODULE_DESCRIPTION("Comedi low-level driver");
651 MODULE_LICENSE("GPL");