2 comedi/drivers/comedi_test.c
4 Generates fake waveform signals that can be read through
5 the command interface. It does _not_ read from any board;
6 it just generates deterministic waveforms.
7 Useful for various testing purposes.
9 Copyright (C) 2002 Joachim Wuttke <Joachim.Wuttke@icn.siemens.de>
10 Copyright (C) 2002 Frank Mori Hess <fmhess@users.sourceforge.net>
12 COMEDI - Linux Control and Measurement Device Interface
13 Copyright (C) 2000 David A. Schleef <ds@schleef.org>
15 This program is free software; you can redistribute it and/or modify
16 it under the terms of the GNU General Public License as published by
17 the Free Software Foundation; either version 2 of the License, or
18 (at your option) any later version.
20 This program is distributed in the hope that it will be useful,
21 but WITHOUT ANY WARRANTY; without even the implied warranty of
22 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
23 GNU General Public License for more details.
25 You should have received a copy of the GNU General Public License
26 along with this program; if not, write to the Free Software
27 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
29 ************************************************************************/
32 Description: generates fake waveforms
33 Author: Joachim Wuttke <Joachim.Wuttke@icn.siemens.de>, Frank Mori Hess
34 <fmhess@users.sourceforge.net>, ds
37 Updated: Sat, 16 Mar 2002 17:34:48 -0800
39 This driver is mainly for testing purposes, but can also be used to
40 generate sample waveforms on systems that don't have data acquisition
43 Configuration options:
44 [0] - Amplitude in microvolts for fake waveforms (default 1 volt)
45 [1] - Period in microseconds for fake waveforms (default 0.1 sec)
47 Generates a sawtooth wave on channel 0, square wave on channel 1, additional
48 waveforms could be added to other channels (currently they return flatline
53 #include "../comedidev.h"
55 #include <asm/div64.h>
57 #include "comedi_fc.h"
58 #include <linux/timer.h>
62 /* Data unique to this driver */
63 struct waveform_private {
64 struct timer_list timer;
65 struct timeval last; /* time last timer interrupt occurred */
66 unsigned int uvolt_amplitude; /* waveform amplitude in microvolts */
67 unsigned long usec_period; /* waveform period in microseconds */
68 unsigned long usec_current; /* current time (mod waveform period) */
69 unsigned long usec_remainder; /* usec since last scan */
70 unsigned long ai_count; /* number of conversions remaining */
71 unsigned int scan_period; /* scan period in usec */
72 unsigned int convert_period; /* conversion period in usec */
73 unsigned int ao_loopbacks[N_CHANS];
76 /* 1000 nanosec in a microsec */
77 static const int nano_per_micro = 1000;
79 /* fake analog input ranges */
80 static const struct comedi_lrange waveform_ai_ranges = {
88 static unsigned short fake_sawtooth(struct comedi_device *dev,
89 unsigned int range_index,
90 unsigned long current_time)
92 struct waveform_private *devpriv = dev->private;
93 struct comedi_subdevice *s = dev->read_subdev;
94 unsigned int offset = s->maxdata / 2;
96 const struct comedi_krange *krange =
97 &s->range_table->range[range_index];
100 binary_amplitude = s->maxdata;
101 binary_amplitude *= devpriv->uvolt_amplitude;
102 do_div(binary_amplitude, krange->max - krange->min);
104 current_time %= devpriv->usec_period;
105 value = current_time;
106 value *= binary_amplitude * 2;
107 do_div(value, devpriv->usec_period);
108 value -= binary_amplitude; /* get rid of sawtooth's dc offset */
110 return offset + value;
113 static unsigned short fake_squarewave(struct comedi_device *dev,
114 unsigned int range_index,
115 unsigned long current_time)
117 struct waveform_private *devpriv = dev->private;
118 struct comedi_subdevice *s = dev->read_subdev;
119 unsigned int offset = s->maxdata / 2;
121 const struct comedi_krange *krange =
122 &s->range_table->range[range_index];
123 current_time %= devpriv->usec_period;
126 value *= devpriv->uvolt_amplitude;
127 do_div(value, krange->max - krange->min);
129 if (current_time < devpriv->usec_period / 2)
132 return offset + value;
135 static unsigned short fake_flatline(struct comedi_device *dev,
136 unsigned int range_index,
137 unsigned long current_time)
139 return dev->read_subdev->maxdata / 2;
142 /* generates a different waveform depending on what channel is read */
143 static unsigned short fake_waveform(struct comedi_device *dev,
144 unsigned int channel, unsigned int range,
145 unsigned long current_time)
153 return fake_sawtooth(dev, range, current_time);
156 return fake_squarewave(dev, range, current_time);
162 return fake_flatline(dev, range, current_time);
166 This is the background routine used to generate arbitrary data.
167 It should run in the background; therefore it is scheduled by
170 static void waveform_ai_interrupt(unsigned long arg)
172 struct comedi_device *dev = (struct comedi_device *)arg;
173 struct waveform_private *devpriv = dev->private;
174 struct comedi_async *async = dev->read_subdev->async;
175 struct comedi_cmd *cmd = &async->cmd;
177 /* all times in microsec */
178 unsigned long elapsed_time;
179 unsigned int num_scans;
181 bool stopping = false;
183 do_gettimeofday(&now);
186 1000000 * (now.tv_sec - devpriv->last.tv_sec) + now.tv_usec -
187 devpriv->last.tv_usec;
190 (devpriv->usec_remainder + elapsed_time) / devpriv->scan_period;
191 devpriv->usec_remainder =
192 (devpriv->usec_remainder + elapsed_time) % devpriv->scan_period;
195 if (cmd->stop_src == TRIG_COUNT) {
196 unsigned int remaining = cmd->stop_arg - devpriv->ai_count;
197 if (num_scans >= remaining) {
198 /* about to finish */
199 num_scans = remaining;
204 for (i = 0; i < num_scans; i++) {
205 for (j = 0; j < cmd->chanlist_len; j++) {
206 unsigned short sample;
207 sample = fake_waveform(dev, CR_CHAN(cmd->chanlist[j]),
208 CR_RANGE(cmd->chanlist[j]),
209 devpriv->usec_current +
210 i * devpriv->scan_period +
211 j * devpriv->convert_period);
212 cfc_write_to_buffer(dev->read_subdev, sample);
216 devpriv->ai_count += i;
217 devpriv->usec_current += elapsed_time;
218 devpriv->usec_current %= devpriv->usec_period;
221 async->events |= COMEDI_CB_EOA;
223 mod_timer(&devpriv->timer, jiffies + 1);
225 comedi_event(dev, dev->read_subdev);
228 static int waveform_ai_cmdtest(struct comedi_device *dev,
229 struct comedi_subdevice *s,
230 struct comedi_cmd *cmd)
235 /* Step 1 : check if triggers are trivially valid */
237 err |= cfc_check_trigger_src(&cmd->start_src, TRIG_NOW);
238 err |= cfc_check_trigger_src(&cmd->scan_begin_src, TRIG_TIMER);
239 err |= cfc_check_trigger_src(&cmd->convert_src, TRIG_NOW | TRIG_TIMER);
240 err |= cfc_check_trigger_src(&cmd->scan_end_src, TRIG_COUNT);
241 err |= cfc_check_trigger_src(&cmd->stop_src, TRIG_COUNT | TRIG_NONE);
246 /* Step 2a : make sure trigger sources are unique */
248 err |= cfc_check_trigger_is_unique(cmd->convert_src);
249 err |= cfc_check_trigger_is_unique(cmd->stop_src);
251 /* Step 2b : and mutually compatible */
256 /* Step 3: check if arguments are trivially valid */
258 err |= cfc_check_trigger_arg_is(&cmd->start_arg, 0);
260 if (cmd->convert_src == TRIG_NOW)
261 err |= cfc_check_trigger_arg_is(&cmd->convert_arg, 0);
263 if (cmd->scan_begin_src == TRIG_TIMER) {
264 err |= cfc_check_trigger_arg_min(&cmd->scan_begin_arg,
266 if (cmd->convert_src == TRIG_TIMER)
267 err |= cfc_check_trigger_arg_min(&cmd->scan_begin_arg,
268 cmd->convert_arg * cmd->chanlist_len);
271 err |= cfc_check_trigger_arg_min(&cmd->chanlist_len, 1);
272 err |= cfc_check_trigger_arg_is(&cmd->scan_end_arg, cmd->chanlist_len);
274 if (cmd->stop_src == TRIG_COUNT)
275 err |= cfc_check_trigger_arg_min(&cmd->stop_arg, 1);
277 err |= cfc_check_trigger_arg_is(&cmd->stop_arg, 0);
282 /* step 4: fix up any arguments */
284 if (cmd->scan_begin_src == TRIG_TIMER) {
285 tmp = cmd->scan_begin_arg;
286 /* round to nearest microsec */
287 cmd->scan_begin_arg =
288 nano_per_micro * ((tmp +
289 (nano_per_micro / 2)) / nano_per_micro);
290 if (tmp != cmd->scan_begin_arg)
293 if (cmd->convert_src == TRIG_TIMER) {
294 tmp = cmd->convert_arg;
295 /* round to nearest microsec */
297 nano_per_micro * ((tmp +
298 (nano_per_micro / 2)) / nano_per_micro);
299 if (tmp != cmd->convert_arg)
309 static int waveform_ai_cmd(struct comedi_device *dev,
310 struct comedi_subdevice *s)
312 struct waveform_private *devpriv = dev->private;
313 struct comedi_cmd *cmd = &s->async->cmd;
315 if (cmd->flags & TRIG_RT) {
317 "commands at RT priority not supported in this driver");
321 devpriv->ai_count = 0;
322 devpriv->scan_period = cmd->scan_begin_arg / nano_per_micro;
324 if (cmd->convert_src == TRIG_NOW)
325 devpriv->convert_period = 0;
326 else if (cmd->convert_src == TRIG_TIMER)
327 devpriv->convert_period = cmd->convert_arg / nano_per_micro;
329 comedi_error(dev, "bug setting conversion period");
333 do_gettimeofday(&devpriv->last);
334 devpriv->usec_current = devpriv->last.tv_usec % devpriv->usec_period;
335 devpriv->usec_remainder = 0;
337 devpriv->timer.expires = jiffies + 1;
338 add_timer(&devpriv->timer);
342 static int waveform_ai_cancel(struct comedi_device *dev,
343 struct comedi_subdevice *s)
345 struct waveform_private *devpriv = dev->private;
347 del_timer_sync(&devpriv->timer);
351 static int waveform_ai_insn_read(struct comedi_device *dev,
352 struct comedi_subdevice *s,
353 struct comedi_insn *insn, unsigned int *data)
355 struct waveform_private *devpriv = dev->private;
356 int i, chan = CR_CHAN(insn->chanspec);
358 for (i = 0; i < insn->n; i++)
359 data[i] = devpriv->ao_loopbacks[chan];
364 static int waveform_ao_insn_write(struct comedi_device *dev,
365 struct comedi_subdevice *s,
366 struct comedi_insn *insn, unsigned int *data)
368 struct waveform_private *devpriv = dev->private;
369 int i, chan = CR_CHAN(insn->chanspec);
371 for (i = 0; i < insn->n; i++)
372 devpriv->ao_loopbacks[chan] = data[i];
377 static int waveform_attach(struct comedi_device *dev,
378 struct comedi_devconfig *it)
380 struct waveform_private *devpriv;
381 struct comedi_subdevice *s;
382 int amplitude = it->options[0];
383 int period = it->options[1];
387 devpriv = kzalloc(sizeof(*devpriv), GFP_KERNEL);
390 dev->private = devpriv;
392 /* set default amplitude and period */
394 amplitude = 1000000; /* 1 volt */
396 period = 100000; /* 0.1 sec */
398 devpriv->uvolt_amplitude = amplitude;
399 devpriv->usec_period = period;
401 ret = comedi_alloc_subdevices(dev, 2);
405 s = &dev->subdevices[0];
406 dev->read_subdev = s;
407 /* analog input subdevice */
408 s->type = COMEDI_SUBD_AI;
409 s->subdev_flags = SDF_READABLE | SDF_GROUND | SDF_CMD_READ;
412 s->range_table = &waveform_ai_ranges;
413 s->len_chanlist = s->n_chan * 2;
414 s->insn_read = waveform_ai_insn_read;
415 s->do_cmd = waveform_ai_cmd;
416 s->do_cmdtest = waveform_ai_cmdtest;
417 s->cancel = waveform_ai_cancel;
419 s = &dev->subdevices[1];
420 dev->write_subdev = s;
421 /* analog output subdevice (loopback) */
422 s->type = COMEDI_SUBD_AO;
423 s->subdev_flags = SDF_WRITEABLE | SDF_GROUND;
426 s->range_table = &waveform_ai_ranges;
427 s->len_chanlist = s->n_chan * 2;
428 s->insn_write = waveform_ao_insn_write;
430 s->do_cmdtest = NULL;
433 /* Our default loopback value is just a 0V flatline */
434 for (i = 0; i < s->n_chan; i++)
435 devpriv->ao_loopbacks[i] = s->maxdata / 2;
437 init_timer(&(devpriv->timer));
438 devpriv->timer.function = waveform_ai_interrupt;
439 devpriv->timer.data = (unsigned long)dev;
441 dev_info(dev->class_dev,
442 "%s: %i microvolt, %li microsecond waveform attached\n",
444 devpriv->uvolt_amplitude, devpriv->usec_period);
449 static void waveform_detach(struct comedi_device *dev)
451 struct waveform_private *devpriv = dev->private;
454 waveform_ai_cancel(dev, dev->read_subdev);
457 static struct comedi_driver waveform_driver = {
458 .driver_name = "comedi_test",
459 .module = THIS_MODULE,
460 .attach = waveform_attach,
461 .detach = waveform_detach,
463 module_comedi_driver(waveform_driver);
465 MODULE_AUTHOR("Comedi http://www.comedi.org");
466 MODULE_DESCRIPTION("Comedi low-level driver");
467 MODULE_LICENSE("GPL");