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 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 <linux/comedidev.h>
77 #include <linux/pci.h> /* for PCI devices */
80 /* Imaginary registers for the imaginary board */
84 #define SKEL_START_AI_CONV 0
85 #define SKEL_AI_READ 0
88 * Board descriptions for two imaginary boards. Describing the
89 * boards in this way is optional, and completely driver-dependent.
90 * Some drivers use arrays such as this, other do not.
92 typedef struct skel_board_struct{
98 static 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 struct pci_device_id skel_pci_table[] __devinitdata = {
119 { PCI_VENDOR_ID_SKEL, 0x0100, PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0 },
120 { 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 ((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 comedi_device struct. */
136 /* would be useful for a PCI device */
137 struct pci_dev *pci_dev;
139 /* Used for AO readback */
140 lsampl_t 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 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(comedi_device *dev,comedi_devconfig *it);
155 static int skel_detach(comedi_device *dev);
156 static comedi_driver driver_skel={
157 driver_name: "dummy",
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(comedi_device *dev,comedi_subdevice *s,comedi_insn *insn,lsampl_t *data);
185 static int skel_ao_winsn(comedi_device *dev,comedi_subdevice *s,comedi_insn *insn,lsampl_t *data);
186 static int skel_ao_rinsn(comedi_device *dev,comedi_subdevice *s,comedi_insn *insn,lsampl_t *data);
187 static int skel_dio_insn_bits(comedi_device *dev,comedi_subdevice *s,
188 comedi_insn *insn,lsampl_t *data);
189 static int skel_dio_insn_config(comedi_device *dev,comedi_subdevice *s,
190 comedi_insn *insn,lsampl_t *data);
191 static int skel_ai_cmdtest(comedi_device *dev,comedi_subdevice *s,
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(comedi_device *dev,comedi_devconfig *it)
205 printk("comedi%d: skel: ",dev->minor);
208 * If you can probe the device to determine what device in a series
209 * it is, this is the place to do it. Otherwise, dev->board_ptr
210 * should already be initialized.
212 //dev->board_ptr = skel_probe(dev);
215 * Initialize dev->board_name. Note that we can use the "thisboard"
216 * macro now, since we just initialized it in the last line.
218 dev->board_name = thisboard->name;
221 * Allocate the private structure area. alloc_private() is a
222 * convenient macro defined in comedidev.h.
224 if(alloc_private(dev,sizeof(skel_private))<0)
228 * Allocate the subdevice structures. alloc_subdevice() is a
229 * convenient macro defined in comedidev.h.
231 if(alloc_subdevices(dev, 3)<0)
235 //dev->read_subdev=s;
236 /* analog input subdevice */
237 s->type=COMEDI_SUBD_AI;
238 /* we support single-ended (ground) and differential */
239 s->subdev_flags=SDF_READABLE|SDF_GROUND|SDF_DIFF;
240 s->n_chan=thisboard->ai_chans;
241 s->maxdata=(1<<thisboard->ai_bits)-1;
242 s->range_table=&range_bipolar10;
243 s->len_chanlist=16; /* This is the maximum chanlist length that
244 the board can handle */
245 s->insn_read = skel_ai_rinsn;
246 // s->subdev_flags |= SDF_CMD_READ;
247 // s->do_cmd = skel_ai_cmd;
248 s->do_cmdtest = skel_ai_cmdtest;
251 /* analog output subdevice */
252 s->type=COMEDI_SUBD_AO;
253 s->subdev_flags=SDF_WRITABLE;
256 s->range_table=&range_bipolar5;
257 s->insn_write = skel_ao_winsn;
258 s->insn_read = skel_ao_rinsn;
261 /* digital i/o subdevice */
262 if(thisboard->have_dio){
263 s->type=COMEDI_SUBD_DIO;
264 s->subdev_flags=SDF_READABLE|SDF_WRITABLE;
267 s->range_table=&range_digital;
268 s->insn_bits = skel_dio_insn_bits;
269 s->insn_config = skel_dio_insn_config;
271 s->type = COMEDI_SUBD_UNUSED;
274 printk("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 int skel_detach(comedi_device *dev)
290 printk("comedi%d: skel: remove\n",dev->minor);
296 * "instructions" read/write data in "one-shot" or "software-triggered"
299 static int skel_ai_rinsn(comedi_device *dev,comedi_subdevice *s,comedi_insn *insn,lsampl_t *data)
305 /* a typical programming sequence */
307 /* write channel to multiplexer */
308 //outw(chan,dev->iobase + SKEL_MUX);
310 /* don't wait for mux to settle */
312 /* convert n samples */
313 for(n=0;n<insn->n;n++){
314 /* trigger conversion */
315 //outw(0,dev->iobase + SKEL_CONVERT);
318 /* wait for conversion to end */
319 for(i=0;i<TIMEOUT;i++){
321 //status = inb(dev->iobase + SKEL_STATUS);
325 /* rt_printk() should be used instead of printk()
326 * whenever the code can be called from real-time. */
327 rt_printk("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 */
345 static int skel_ai_cmdtest(comedi_device *dev,comedi_subdevice *s,
351 /* cmdtest tests a particular command to see if it is valid.
352 * Using the cmdtest ioctl, a user can create a valid cmd
353 * and then have it executes by the cmd ioctl.
355 * cmdtest returns 1,2,3,4 or 0, depending on which tests
356 * the command passes. */
358 /* step 1: make sure trigger sources are trivially valid */
361 cmd->start_src &= TRIG_NOW;
362 if(!cmd->start_src || tmp!=cmd->start_src)err++;
364 tmp=cmd->scan_begin_src;
365 cmd->scan_begin_src &= TRIG_TIMER|TRIG_EXT;
366 if(!cmd->scan_begin_src || tmp!=cmd->scan_begin_src)err++;
368 tmp=cmd->convert_src;
369 cmd->convert_src &= TRIG_TIMER|TRIG_EXT;
370 if(!cmd->convert_src || tmp!=cmd->convert_src)err++;
372 tmp=cmd->scan_end_src;
373 cmd->scan_end_src &= TRIG_COUNT;
374 if(!cmd->scan_end_src || tmp!=cmd->scan_end_src)err++;
377 cmd->stop_src &= TRIG_COUNT|TRIG_NONE;
378 if(!cmd->stop_src || tmp!=cmd->stop_src)err++;
382 /* step 2: make sure trigger sources are unique and mutually compatible */
384 /* note that mutual compatiblity is not an issue here */
385 if(cmd->scan_begin_src!=TRIG_TIMER &&
386 cmd->scan_begin_src!=TRIG_EXT)err++;
387 if(cmd->convert_src!=TRIG_TIMER &&
388 cmd->convert_src!=TRIG_EXT)err++;
389 if(cmd->stop_src!=TRIG_COUNT &&
390 cmd->stop_src!=TRIG_NONE)err++;
394 /* step 3: make sure arguments are trivially compatible */
396 if(cmd->start_arg!=0){
401 #define MAX_SPEED 10000 /* in nanoseconds */
402 #define MIN_SPEED 1000000000 /* in nanoseconds */
404 if(cmd->scan_begin_src==TRIG_TIMER){
405 if(cmd->scan_begin_arg<MAX_SPEED){
406 cmd->scan_begin_arg=MAX_SPEED;
409 if(cmd->scan_begin_arg>MIN_SPEED){
410 cmd->scan_begin_arg=MIN_SPEED;
414 /* external trigger */
415 /* should be level/edge, hi/lo specification here */
416 /* should specify multiple external triggers */
417 if(cmd->scan_begin_arg>9){
418 cmd->scan_begin_arg=9;
422 if(cmd->convert_src==TRIG_TIMER){
423 if(cmd->convert_arg<MAX_SPEED){
424 cmd->convert_arg=MAX_SPEED;
427 if(cmd->convert_arg>MIN_SPEED){
428 cmd->convert_arg=MIN_SPEED;
432 /* external trigger */
434 if(cmd->convert_arg>9){
440 if(cmd->scan_end_arg!=cmd->chanlist_len){
441 cmd->scan_end_arg=cmd->chanlist_len;
444 if(cmd->stop_src==TRIG_COUNT){
445 if(cmd->stop_arg>0x00ffffff){
446 cmd->stop_arg=0x00ffffff;
451 if(cmd->stop_arg!=0){
459 /* step 4: fix up any arguments */
461 if(cmd->scan_begin_src==TRIG_TIMER){
462 tmp=cmd->scan_begin_arg;
463 skel_ns_to_timer(&cmd->scan_begin_arg,cmd->flags&TRIG_ROUND_MASK);
464 if(tmp!=cmd->scan_begin_arg)err++;
466 if(cmd->convert_src==TRIG_TIMER){
467 tmp=cmd->convert_arg;
468 skel_ns_to_timer(&cmd->convert_arg,cmd->flags&TRIG_ROUND_MASK);
469 if(tmp!=cmd->convert_arg)err++;
470 if(cmd->scan_begin_src==TRIG_TIMER &&
471 cmd->scan_begin_arg<cmd->convert_arg*cmd->scan_end_arg){
472 cmd->scan_begin_arg=cmd->convert_arg*cmd->scan_end_arg;
482 /* This function doesn't require a particular form, this is just
483 * what happens to be used in some of the drivers. It should
484 * convert ns nanoseconds to a counter value suitable for programming
485 * the device. Also, it should adjust ns so that it cooresponds to
486 * the actual time that the device will use. */
487 static int skel_ns_to_timer(unsigned int *ns,int round)
490 /* if your timing is done through two cascaded timers, the
491 * i8253_cascade_ns_to_timer() function in 8253.h can be
492 * very helpful. There are also i8254_load() and i8254_mm_load()
493 * which can be used to load values into the ubiquitous 8254 counters
500 static int skel_ao_winsn(comedi_device *dev,comedi_subdevice *s,comedi_insn *insn,lsampl_t *data)
503 int chan = CR_CHAN(insn->chanspec);
505 printk("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(comedi_device *dev,comedi_subdevice *s,comedi_insn *insn,lsampl_t *data)
523 int chan = CR_CHAN(insn->chanspec);
525 for(i=0;i<insn->n;i++)
526 data[i] = devpriv->ao_readback[chan];
531 /* DIO devices are slightly special. Although it is possible to
532 * implement the insn_read/insn_write interface, it is much more
533 * useful to applications if you implement the insn_bits interface.
534 * This allows packed reading/writing of the DIO channels. The
535 * comedi core can convert between insn_bits and insn_read/write */
536 static int skel_dio_insn_bits(comedi_device *dev,comedi_subdevice *s,
537 comedi_insn *insn,lsampl_t *data)
539 if(insn->n!=2)return -EINVAL;
541 /* The insn data is a mask in data[0] and the new data
542 * in data[1], each channel cooresponding to a bit. */
544 s->state &= ~data[0];
545 s->state |= data[0]&data[1];
546 /* Write out the new digital output lines */
547 //outw(s->state,dev->iobase + SKEL_DIO);
550 /* on return, data[1] contains the value of the digital
551 * input and output lines. */
552 //data[1]=inw(dev->iobase + SKEL_DIO);
553 /* or we could just return the software copy of the output values if
554 * it was a purely digital output subdevice */
560 static int skel_dio_insn_config(comedi_device *dev,comedi_subdevice *s,
561 comedi_insn *insn,lsampl_t *data)
563 int chan=CR_CHAN(insn->chanspec);
565 /* The input or output configuration of each digital line is
566 * configured by a special insn_config instruction. chanspec
567 * contains the channel to be changed, and data[0] contains the
568 * value COMEDI_INPUT or COMEDI_OUTPUT. */
571 case INSN_CONFIG_DIO_OUTPUT:
572 s->io_bits |= 1<<chan;
574 case INSN_CONFIG_DIO_INPUT:
575 s->io_bits &= ~(1<<chan);
577 case INSN_CONFIG_DIO_QUERY:
578 data[1] = (s->io_bits & (1 << chan)) ? COMEDI_OUTPUT : COMEDI_INPUT;
585 //outw(s->io_bits,dev->iobase + SKEL_DIO_CONFIG);
591 * A convenient macro that defines init_module() and cleanup_module(),
594 COMEDI_INITCLEANUP(driver_skel);