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.
27 Description: generates fake waveforms
28 Author: Joachim Wuttke <Joachim.Wuttke@icn.siemens.de>, Frank Mori Hess
29 <fmhess@users.sourceforge.net>, ds
32 Updated: Sat, 16 Mar 2002 17:34:48 -0800
34 This driver is mainly for testing purposes, but can also be used to
35 generate sample waveforms on systems that don't have data acquisition
38 Configuration options:
39 [0] - Amplitude in microvolts for fake waveforms (default 1 volt)
40 [1] - Period in microseconds for fake waveforms (default 0.1 sec)
42 Generates a sawtooth wave on channel 0, square wave on channel 1, additional
43 waveforms could be added to other channels (currently they return flatline
48 #include <linux/module.h>
49 #include "../comedidev.h"
51 #include <asm/div64.h>
53 #include "comedi_fc.h"
54 #include <linux/timer.h>
58 /* Data unique to this driver */
59 struct waveform_private {
60 struct timer_list timer;
61 struct timeval last; /* time last timer interrupt occurred */
62 unsigned int uvolt_amplitude; /* waveform amplitude in microvolts */
63 unsigned long usec_period; /* waveform period in microseconds */
64 unsigned long usec_current; /* current time (mod waveform period) */
65 unsigned long usec_remainder; /* usec since last scan */
66 unsigned long ai_count; /* number of conversions remaining */
67 unsigned int scan_period; /* scan period in usec */
68 unsigned int convert_period; /* conversion period in usec */
69 unsigned int ao_loopbacks[N_CHANS];
72 /* 1000 nanosec in a microsec */
73 static const int nano_per_micro = 1000;
75 /* fake analog input ranges */
76 static const struct comedi_lrange waveform_ai_ranges = {
84 static unsigned short fake_sawtooth(struct comedi_device *dev,
85 unsigned int range_index,
86 unsigned long current_time)
88 struct waveform_private *devpriv = dev->private;
89 struct comedi_subdevice *s = dev->read_subdev;
90 unsigned int offset = s->maxdata / 2;
92 const struct comedi_krange *krange =
93 &s->range_table->range[range_index];
96 binary_amplitude = s->maxdata;
97 binary_amplitude *= devpriv->uvolt_amplitude;
98 do_div(binary_amplitude, krange->max - krange->min);
100 current_time %= devpriv->usec_period;
101 value = current_time;
102 value *= binary_amplitude * 2;
103 do_div(value, devpriv->usec_period);
104 value -= binary_amplitude; /* get rid of sawtooth's dc offset */
106 return offset + value;
109 static unsigned short fake_squarewave(struct comedi_device *dev,
110 unsigned int range_index,
111 unsigned long current_time)
113 struct waveform_private *devpriv = dev->private;
114 struct comedi_subdevice *s = dev->read_subdev;
115 unsigned int offset = s->maxdata / 2;
117 const struct comedi_krange *krange =
118 &s->range_table->range[range_index];
119 current_time %= devpriv->usec_period;
122 value *= devpriv->uvolt_amplitude;
123 do_div(value, krange->max - krange->min);
125 if (current_time < devpriv->usec_period / 2)
128 return offset + value;
131 static unsigned short fake_flatline(struct comedi_device *dev,
132 unsigned int range_index,
133 unsigned long current_time)
135 return dev->read_subdev->maxdata / 2;
138 /* generates a different waveform depending on what channel is read */
139 static unsigned short fake_waveform(struct comedi_device *dev,
140 unsigned int channel, unsigned int range,
141 unsigned long current_time)
149 return fake_sawtooth(dev, range, current_time);
152 return fake_squarewave(dev, range, current_time);
158 return fake_flatline(dev, range, current_time);
162 This is the background routine used to generate arbitrary data.
163 It should run in the background; therefore it is scheduled by
166 static void waveform_ai_interrupt(unsigned long arg)
168 struct comedi_device *dev = (struct comedi_device *)arg;
169 struct waveform_private *devpriv = dev->private;
170 struct comedi_async *async = dev->read_subdev->async;
171 struct comedi_cmd *cmd = &async->cmd;
173 /* all times in microsec */
174 unsigned long elapsed_time;
175 unsigned int num_scans;
177 bool stopping = false;
179 do_gettimeofday(&now);
182 1000000 * (now.tv_sec - devpriv->last.tv_sec) + now.tv_usec -
183 devpriv->last.tv_usec;
186 (devpriv->usec_remainder + elapsed_time) / devpriv->scan_period;
187 devpriv->usec_remainder =
188 (devpriv->usec_remainder + elapsed_time) % devpriv->scan_period;
191 if (cmd->stop_src == TRIG_COUNT) {
192 unsigned int remaining = cmd->stop_arg - devpriv->ai_count;
193 if (num_scans >= remaining) {
194 /* about to finish */
195 num_scans = remaining;
200 for (i = 0; i < num_scans; i++) {
201 for (j = 0; j < cmd->chanlist_len; j++) {
202 unsigned short sample;
203 sample = fake_waveform(dev, CR_CHAN(cmd->chanlist[j]),
204 CR_RANGE(cmd->chanlist[j]),
205 devpriv->usec_current +
206 i * devpriv->scan_period +
207 j * devpriv->convert_period);
208 cfc_write_to_buffer(dev->read_subdev, sample);
212 devpriv->ai_count += i;
213 devpriv->usec_current += elapsed_time;
214 devpriv->usec_current %= devpriv->usec_period;
217 async->events |= COMEDI_CB_EOA;
219 mod_timer(&devpriv->timer, jiffies + 1);
221 comedi_event(dev, dev->read_subdev);
224 static int waveform_ai_cmdtest(struct comedi_device *dev,
225 struct comedi_subdevice *s,
226 struct comedi_cmd *cmd)
231 /* Step 1 : check if triggers are trivially valid */
233 err |= cfc_check_trigger_src(&cmd->start_src, TRIG_NOW);
234 err |= cfc_check_trigger_src(&cmd->scan_begin_src, TRIG_TIMER);
235 err |= cfc_check_trigger_src(&cmd->convert_src, TRIG_NOW | TRIG_TIMER);
236 err |= cfc_check_trigger_src(&cmd->scan_end_src, TRIG_COUNT);
237 err |= cfc_check_trigger_src(&cmd->stop_src, TRIG_COUNT | TRIG_NONE);
242 /* Step 2a : make sure trigger sources are unique */
244 err |= cfc_check_trigger_is_unique(cmd->convert_src);
245 err |= cfc_check_trigger_is_unique(cmd->stop_src);
247 /* Step 2b : and mutually compatible */
252 /* Step 3: check if arguments are trivially valid */
254 err |= cfc_check_trigger_arg_is(&cmd->start_arg, 0);
256 if (cmd->convert_src == TRIG_NOW)
257 err |= cfc_check_trigger_arg_is(&cmd->convert_arg, 0);
259 if (cmd->scan_begin_src == TRIG_TIMER) {
260 err |= cfc_check_trigger_arg_min(&cmd->scan_begin_arg,
262 if (cmd->convert_src == TRIG_TIMER)
263 err |= cfc_check_trigger_arg_min(&cmd->scan_begin_arg,
264 cmd->convert_arg * cmd->chanlist_len);
267 err |= cfc_check_trigger_arg_min(&cmd->chanlist_len, 1);
268 err |= cfc_check_trigger_arg_is(&cmd->scan_end_arg, cmd->chanlist_len);
270 if (cmd->stop_src == TRIG_COUNT)
271 err |= cfc_check_trigger_arg_min(&cmd->stop_arg, 1);
273 err |= cfc_check_trigger_arg_is(&cmd->stop_arg, 0);
278 /* step 4: fix up any arguments */
280 if (cmd->scan_begin_src == TRIG_TIMER) {
281 tmp = cmd->scan_begin_arg;
282 /* round to nearest microsec */
283 cmd->scan_begin_arg =
284 nano_per_micro * ((tmp +
285 (nano_per_micro / 2)) / nano_per_micro);
286 if (tmp != cmd->scan_begin_arg)
289 if (cmd->convert_src == TRIG_TIMER) {
290 tmp = cmd->convert_arg;
291 /* round to nearest microsec */
293 nano_per_micro * ((tmp +
294 (nano_per_micro / 2)) / nano_per_micro);
295 if (tmp != cmd->convert_arg)
305 static int waveform_ai_cmd(struct comedi_device *dev,
306 struct comedi_subdevice *s)
308 struct waveform_private *devpriv = dev->private;
309 struct comedi_cmd *cmd = &s->async->cmd;
311 if (cmd->flags & TRIG_RT) {
313 "commands at RT priority not supported in this driver");
317 devpriv->ai_count = 0;
318 devpriv->scan_period = cmd->scan_begin_arg / nano_per_micro;
320 if (cmd->convert_src == TRIG_NOW)
321 devpriv->convert_period = 0;
322 else if (cmd->convert_src == TRIG_TIMER)
323 devpriv->convert_period = cmd->convert_arg / nano_per_micro;
325 comedi_error(dev, "bug setting conversion period");
329 do_gettimeofday(&devpriv->last);
330 devpriv->usec_current = devpriv->last.tv_usec % devpriv->usec_period;
331 devpriv->usec_remainder = 0;
333 devpriv->timer.expires = jiffies + 1;
334 add_timer(&devpriv->timer);
338 static int waveform_ai_cancel(struct comedi_device *dev,
339 struct comedi_subdevice *s)
341 struct waveform_private *devpriv = dev->private;
343 del_timer_sync(&devpriv->timer);
347 static int waveform_ai_insn_read(struct comedi_device *dev,
348 struct comedi_subdevice *s,
349 struct comedi_insn *insn, unsigned int *data)
351 struct waveform_private *devpriv = dev->private;
352 int i, chan = CR_CHAN(insn->chanspec);
354 for (i = 0; i < insn->n; i++)
355 data[i] = devpriv->ao_loopbacks[chan];
360 static int waveform_ao_insn_write(struct comedi_device *dev,
361 struct comedi_subdevice *s,
362 struct comedi_insn *insn, unsigned int *data)
364 struct waveform_private *devpriv = dev->private;
365 int i, chan = CR_CHAN(insn->chanspec);
367 for (i = 0; i < insn->n; i++)
368 devpriv->ao_loopbacks[chan] = data[i];
373 static int waveform_attach(struct comedi_device *dev,
374 struct comedi_devconfig *it)
376 struct waveform_private *devpriv;
377 struct comedi_subdevice *s;
378 int amplitude = it->options[0];
379 int period = it->options[1];
383 devpriv = comedi_alloc_devpriv(dev, sizeof(*devpriv));
387 /* set default amplitude and period */
389 amplitude = 1000000; /* 1 volt */
391 period = 100000; /* 0.1 sec */
393 devpriv->uvolt_amplitude = amplitude;
394 devpriv->usec_period = period;
396 ret = comedi_alloc_subdevices(dev, 2);
400 s = &dev->subdevices[0];
401 dev->read_subdev = s;
402 /* analog input subdevice */
403 s->type = COMEDI_SUBD_AI;
404 s->subdev_flags = SDF_READABLE | SDF_GROUND | SDF_CMD_READ;
407 s->range_table = &waveform_ai_ranges;
408 s->len_chanlist = s->n_chan * 2;
409 s->insn_read = waveform_ai_insn_read;
410 s->do_cmd = waveform_ai_cmd;
411 s->do_cmdtest = waveform_ai_cmdtest;
412 s->cancel = waveform_ai_cancel;
414 s = &dev->subdevices[1];
415 dev->write_subdev = s;
416 /* analog output subdevice (loopback) */
417 s->type = COMEDI_SUBD_AO;
418 s->subdev_flags = SDF_WRITEABLE | SDF_GROUND;
421 s->range_table = &waveform_ai_ranges;
422 s->len_chanlist = s->n_chan * 2;
423 s->insn_write = waveform_ao_insn_write;
425 s->do_cmdtest = NULL;
428 /* Our default loopback value is just a 0V flatline */
429 for (i = 0; i < s->n_chan; i++)
430 devpriv->ao_loopbacks[i] = s->maxdata / 2;
432 init_timer(&(devpriv->timer));
433 devpriv->timer.function = waveform_ai_interrupt;
434 devpriv->timer.data = (unsigned long)dev;
436 dev_info(dev->class_dev,
437 "%s: %i microvolt, %li microsecond waveform attached\n",
439 devpriv->uvolt_amplitude, devpriv->usec_period);
444 static void waveform_detach(struct comedi_device *dev)
446 struct waveform_private *devpriv = dev->private;
449 waveform_ai_cancel(dev, dev->read_subdev);
452 static struct comedi_driver waveform_driver = {
453 .driver_name = "comedi_test",
454 .module = THIS_MODULE,
455 .attach = waveform_attach,
456 .detach = waveform_detach,
458 module_comedi_driver(waveform_driver);
460 MODULE_AUTHOR("Comedi http://www.comedi.org");
461 MODULE_DESCRIPTION("Comedi low-level driver");
462 MODULE_LICENSE("GPL");