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.
91 typedef struct skel_board_struct {
97 static const skel_board skel_boards[] = {
112 /* This is used by modprobe to translate PCI IDs to drivers. Should
113 * only be used for PCI and ISA-PnP devices */
114 /* Please add your PCI vendor ID to comedidev.h, and it will be forwarded
116 #define PCI_VENDOR_ID_SKEL 0xdafe
117 static DEFINE_PCI_DEVICE_TABLE(skel_pci_table) = {
118 {PCI_VENDOR_ID_SKEL, 0x0100, PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0},
119 {PCI_VENDOR_ID_SKEL, 0x0200, PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0},
123 MODULE_DEVICE_TABLE(pci, skel_pci_table);
126 * Useful for shorthand access to the particular board structure
128 #define thisboard ((const skel_board *)dev->board_ptr)
130 /* this structure is for data unique to this hardware driver. If
131 several hardware drivers keep similar information in this structure,
132 feel free to suggest moving the variable to the struct comedi_device struct. */
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];
143 * most drivers define the following macro to make it easy to
144 * access the private structure.
146 #define devpriv ((skel_private *)dev->private)
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 int skel_detach(struct comedi_device * dev);
156 static struct comedi_driver driver_skel = {
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(skel_board),
181 num_names:sizeof(skel_boards) / sizeof(skel_board),
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, struct comedi_subdevice * s,
191 struct comedi_insn * insn, unsigned int * data);
192 static int skel_dio_insn_config(struct comedi_device * dev, struct comedi_subdevice * s,
193 struct comedi_insn * insn, unsigned int * data);
194 static int skel_ai_cmdtest(struct comedi_device * dev, struct comedi_subdevice * s,
195 struct comedi_cmd * cmd);
196 static int skel_ns_to_timer(unsigned int *ns, int round);
199 * Attach is called by the Comedi core to configure the driver
200 * for a particular board. If you specified a board_name array
201 * in the driver structure, dev->board_ptr contains that
204 static int skel_attach(struct comedi_device * dev, struct comedi_devconfig * it)
206 struct comedi_subdevice *s;
208 printk("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);
218 * Initialize dev->board_name. Note that we can use the "thisboard"
219 * macro now, since we just initialized it in the last line.
221 dev->board_name = thisboard->name;
224 * Allocate the private structure area. alloc_private() is a
225 * convenient macro defined in comedidev.h.
227 if (alloc_private(dev, sizeof(skel_private)) < 0)
231 * Allocate the subdevice structures. alloc_subdevice() is a
232 * convenient macro defined in comedidev.h.
234 if (alloc_subdevices(dev, 3) < 0)
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;
249 // s->subdev_flags |= SDF_CMD_READ;
250 // s->do_cmd = skel_ai_cmd;
251 s->do_cmdtest = skel_ai_cmdtest;
253 s = dev->subdevices + 1;
254 /* analog output subdevice */
255 s->type = COMEDI_SUBD_AO;
256 s->subdev_flags = SDF_WRITABLE;
259 s->range_table = &range_bipolar5;
260 s->insn_write = skel_ao_winsn;
261 s->insn_read = skel_ao_rinsn;
263 s = dev->subdevices + 2;
264 /* digital i/o subdevice */
265 if (thisboard->have_dio) {
266 s->type = COMEDI_SUBD_DIO;
267 s->subdev_flags = SDF_READABLE | SDF_WRITABLE;
270 s->range_table = &range_digital;
271 s->insn_bits = skel_dio_insn_bits;
272 s->insn_config = skel_dio_insn_config;
274 s->type = COMEDI_SUBD_UNUSED;
277 printk("attached\n");
283 * _detach is called to deconfigure a device. It should deallocate
285 * This function is also called when _attach() fails, so it should be
286 * careful not to release resources that were not necessarily
287 * allocated by _attach(). dev->private and dev->subdevices are
288 * deallocated automatically by the core.
290 static int skel_detach(struct comedi_device * dev)
292 printk("comedi%d: skel: remove\n", dev->minor);
298 * "instructions" read/write data in "one-shot" or "software-triggered"
301 static int skel_ai_rinsn(struct comedi_device * dev, struct comedi_subdevice * s,
302 struct comedi_insn * insn, unsigned int * data)
308 /* a typical programming sequence */
310 /* write channel to multiplexer */
311 //outw(chan,dev->iobase + SKEL_MUX);
313 /* don't wait for mux to settle */
315 /* convert n samples */
316 for (n = 0; n < insn->n; n++) {
317 /* trigger conversion */
318 //outw(0,dev->iobase + SKEL_CONVERT);
321 /* wait for conversion to end */
322 for (i = 0; i < TIMEOUT; i++) {
324 //status = inb(dev->iobase + SKEL_STATUS);
329 /* rt_printk() should be used instead of printk()
330 * whenever the code can be called from real-time. */
331 rt_printk("timeout\n");
336 //d = inw(dev->iobase + SKEL_AI_DATA);
339 /* mangle the data as necessary */
340 d ^= 1 << (thisboard->ai_bits - 1);
345 /* return the number of samples read/written */
349 static int skel_ai_cmdtest(struct comedi_device * dev, struct comedi_subdevice * s,
350 struct comedi_cmd * cmd)
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 /* step 1: make sure trigger sources are trivially valid */
364 tmp = cmd->start_src;
365 cmd->start_src &= TRIG_NOW;
366 if (!cmd->start_src || tmp != cmd->start_src)
369 tmp = cmd->scan_begin_src;
370 cmd->scan_begin_src &= TRIG_TIMER | TRIG_EXT;
371 if (!cmd->scan_begin_src || tmp != cmd->scan_begin_src)
374 tmp = cmd->convert_src;
375 cmd->convert_src &= TRIG_TIMER | TRIG_EXT;
376 if (!cmd->convert_src || tmp != cmd->convert_src)
379 tmp = cmd->scan_end_src;
380 cmd->scan_end_src &= TRIG_COUNT;
381 if (!cmd->scan_end_src || tmp != cmd->scan_end_src)
385 cmd->stop_src &= TRIG_COUNT | TRIG_NONE;
386 if (!cmd->stop_src || tmp != cmd->stop_src)
392 /* step 2: make sure trigger sources are unique and mutually compatible */
394 /* note that mutual compatiblity is not an issue here */
395 if (cmd->scan_begin_src != TRIG_TIMER &&
396 cmd->scan_begin_src != TRIG_EXT)
398 if (cmd->convert_src != TRIG_TIMER && cmd->convert_src != TRIG_EXT)
400 if (cmd->stop_src != TRIG_COUNT && cmd->stop_src != TRIG_NONE)
406 /* step 3: make sure arguments are trivially compatible */
408 if (cmd->start_arg != 0) {
412 #define MAX_SPEED 10000 /* in nanoseconds */
413 #define MIN_SPEED 1000000000 /* in nanoseconds */
415 if (cmd->scan_begin_src == TRIG_TIMER) {
416 if (cmd->scan_begin_arg < MAX_SPEED) {
417 cmd->scan_begin_arg = MAX_SPEED;
420 if (cmd->scan_begin_arg > MIN_SPEED) {
421 cmd->scan_begin_arg = MIN_SPEED;
425 /* external trigger */
426 /* should be level/edge, hi/lo specification here */
427 /* should specify multiple external triggers */
428 if (cmd->scan_begin_arg > 9) {
429 cmd->scan_begin_arg = 9;
433 if (cmd->convert_src == TRIG_TIMER) {
434 if (cmd->convert_arg < MAX_SPEED) {
435 cmd->convert_arg = MAX_SPEED;
438 if (cmd->convert_arg > MIN_SPEED) {
439 cmd->convert_arg = MIN_SPEED;
443 /* external trigger */
445 if (cmd->convert_arg > 9) {
446 cmd->convert_arg = 9;
451 if (cmd->scan_end_arg != cmd->chanlist_len) {
452 cmd->scan_end_arg = cmd->chanlist_len;
455 if (cmd->stop_src == TRIG_COUNT) {
456 if (cmd->stop_arg > 0x00ffffff) {
457 cmd->stop_arg = 0x00ffffff;
462 if (cmd->stop_arg != 0) {
471 /* step 4: fix up any arguments */
473 if (cmd->scan_begin_src == TRIG_TIMER) {
474 tmp = cmd->scan_begin_arg;
475 skel_ns_to_timer(&cmd->scan_begin_arg,
476 cmd->flags & TRIG_ROUND_MASK);
477 if (tmp != cmd->scan_begin_arg)
480 if (cmd->convert_src == TRIG_TIMER) {
481 tmp = cmd->convert_arg;
482 skel_ns_to_timer(&cmd->convert_arg,
483 cmd->flags & TRIG_ROUND_MASK);
484 if (tmp != cmd->convert_arg)
486 if (cmd->scan_begin_src == TRIG_TIMER &&
487 cmd->scan_begin_arg <
488 cmd->convert_arg * cmd->scan_end_arg) {
489 cmd->scan_begin_arg =
490 cmd->convert_arg * cmd->scan_end_arg;
501 /* This function doesn't require a particular form, this is just
502 * what happens to be used in some of the drivers. It should
503 * convert ns nanoseconds to a counter value suitable for programming
504 * the device. Also, it should adjust ns so that it cooresponds to
505 * the actual time that the device will use. */
506 static int skel_ns_to_timer(unsigned int *ns, int round)
509 /* if your timing is done through two cascaded timers, the
510 * i8253_cascade_ns_to_timer() function in 8253.h can be
511 * very helpful. There are also i8254_load() and i8254_mm_load()
512 * which can be used to load values into the ubiquitous 8254 counters
518 static int skel_ao_winsn(struct comedi_device * dev, struct comedi_subdevice * s,
519 struct comedi_insn * insn, unsigned int * data)
522 int chan = CR_CHAN(insn->chanspec);
524 printk("skel_ao_winsn\n");
525 /* Writing a list of values to an AO channel is probably not
526 * very useful, but that's how the interface is defined. */
527 for (i = 0; i < insn->n; i++) {
528 /* a typical programming sequence */
529 //outw(data[i],dev->iobase + SKEL_DA0 + chan);
530 devpriv->ao_readback[chan] = data[i];
533 /* return the number of samples read/written */
537 /* AO subdevices should have a read insn as well as a write insn.
538 * Usually this means copying a value stored in devpriv. */
539 static int skel_ao_rinsn(struct comedi_device * dev, struct comedi_subdevice * s,
540 struct comedi_insn * insn, unsigned int * data)
543 int chan = CR_CHAN(insn->chanspec);
545 for (i = 0; i < insn->n; i++)
546 data[i] = devpriv->ao_readback[chan];
551 /* DIO devices are slightly special. Although it is possible to
552 * implement the insn_read/insn_write interface, it is much more
553 * useful to applications if you implement the insn_bits interface.
554 * This allows packed reading/writing of the DIO channels. The
555 * comedi core can convert between insn_bits and insn_read/write */
556 static int skel_dio_insn_bits(struct comedi_device * dev, struct comedi_subdevice * s,
557 struct comedi_insn * insn, unsigned int * data)
562 /* The insn data is a mask in data[0] and the new data
563 * in data[1], each channel cooresponding to a bit. */
565 s->state &= ~data[0];
566 s->state |= data[0] & data[1];
567 /* Write out the new digital output lines */
568 //outw(s->state,dev->iobase + SKEL_DIO);
571 /* on return, data[1] contains the value of the digital
572 * input and output lines. */
573 //data[1]=inw(dev->iobase + SKEL_DIO);
574 /* or we could just return the software copy of the output values if
575 * it was a purely digital output subdevice */
581 static int skel_dio_insn_config(struct comedi_device * dev, struct comedi_subdevice * s,
582 struct comedi_insn * insn, unsigned int * data)
584 int chan = CR_CHAN(insn->chanspec);
586 /* The input or output configuration of each digital line is
587 * configured by a special insn_config instruction. chanspec
588 * contains the channel to be changed, and data[0] contains the
589 * value COMEDI_INPUT or COMEDI_OUTPUT. */
591 case INSN_CONFIG_DIO_OUTPUT:
592 s->io_bits |= 1 << chan;
594 case INSN_CONFIG_DIO_INPUT:
595 s->io_bits &= ~(1 << chan);
597 case INSN_CONFIG_DIO_QUERY:
600 io_bits & (1 << chan)) ? COMEDI_OUTPUT : COMEDI_INPUT;
607 //outw(s->io_bits,dev->iobase + SKEL_DIO_CONFIG);
613 * A convenient macro that defines init_module() and cleanup_module(),
616 COMEDI_INITCLEANUP(driver_skel);
617 /* If you are writing a PCI driver you should use COMEDI_PCI_INITCLEANUP instead.
619 // COMEDI_PCI_INITCLEANUP(driver_skel, skel_pci_table)