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 "../comedidev.h"
50 #include <asm/div64.h>
52 #include "comedi_fc.h"
53 #include <linux/timer.h>
57 /* Data unique to this driver */
58 struct waveform_private {
59 struct timer_list timer;
60 struct timeval last; /* time last timer interrupt occurred */
61 unsigned int uvolt_amplitude; /* waveform amplitude in microvolts */
62 unsigned long usec_period; /* waveform period in microseconds */
63 unsigned long usec_current; /* current time (mod waveform period) */
64 unsigned long usec_remainder; /* usec since last scan */
65 unsigned long ai_count; /* number of conversions remaining */
66 unsigned int scan_period; /* scan period in usec */
67 unsigned int convert_period; /* conversion period in usec */
68 unsigned int ao_loopbacks[N_CHANS];
71 /* 1000 nanosec in a microsec */
72 static const int nano_per_micro = 1000;
74 /* fake analog input ranges */
75 static const struct comedi_lrange waveform_ai_ranges = {
83 static unsigned short fake_sawtooth(struct comedi_device *dev,
84 unsigned int range_index,
85 unsigned long current_time)
87 struct waveform_private *devpriv = dev->private;
88 struct comedi_subdevice *s = dev->read_subdev;
89 unsigned int offset = s->maxdata / 2;
91 const struct comedi_krange *krange =
92 &s->range_table->range[range_index];
95 binary_amplitude = s->maxdata;
96 binary_amplitude *= devpriv->uvolt_amplitude;
97 do_div(binary_amplitude, krange->max - krange->min);
99 current_time %= devpriv->usec_period;
100 value = current_time;
101 value *= binary_amplitude * 2;
102 do_div(value, devpriv->usec_period);
103 value -= binary_amplitude; /* get rid of sawtooth's dc offset */
105 return offset + value;
108 static unsigned short fake_squarewave(struct comedi_device *dev,
109 unsigned int range_index,
110 unsigned long current_time)
112 struct waveform_private *devpriv = dev->private;
113 struct comedi_subdevice *s = dev->read_subdev;
114 unsigned int offset = s->maxdata / 2;
116 const struct comedi_krange *krange =
117 &s->range_table->range[range_index];
118 current_time %= devpriv->usec_period;
121 value *= devpriv->uvolt_amplitude;
122 do_div(value, krange->max - krange->min);
124 if (current_time < devpriv->usec_period / 2)
127 return offset + value;
130 static unsigned short fake_flatline(struct comedi_device *dev,
131 unsigned int range_index,
132 unsigned long current_time)
134 return dev->read_subdev->maxdata / 2;
137 /* generates a different waveform depending on what channel is read */
138 static unsigned short fake_waveform(struct comedi_device *dev,
139 unsigned int channel, unsigned int range,
140 unsigned long current_time)
148 return fake_sawtooth(dev, range, current_time);
151 return fake_squarewave(dev, range, current_time);
157 return fake_flatline(dev, range, current_time);
161 This is the background routine used to generate arbitrary data.
162 It should run in the background; therefore it is scheduled by
165 static void waveform_ai_interrupt(unsigned long arg)
167 struct comedi_device *dev = (struct comedi_device *)arg;
168 struct waveform_private *devpriv = dev->private;
169 struct comedi_async *async = dev->read_subdev->async;
170 struct comedi_cmd *cmd = &async->cmd;
172 /* all times in microsec */
173 unsigned long elapsed_time;
174 unsigned int num_scans;
176 bool stopping = false;
178 do_gettimeofday(&now);
181 1000000 * (now.tv_sec - devpriv->last.tv_sec) + now.tv_usec -
182 devpriv->last.tv_usec;
185 (devpriv->usec_remainder + elapsed_time) / devpriv->scan_period;
186 devpriv->usec_remainder =
187 (devpriv->usec_remainder + elapsed_time) % devpriv->scan_period;
190 if (cmd->stop_src == TRIG_COUNT) {
191 unsigned int remaining = cmd->stop_arg - devpriv->ai_count;
192 if (num_scans >= remaining) {
193 /* about to finish */
194 num_scans = remaining;
199 for (i = 0; i < num_scans; i++) {
200 for (j = 0; j < cmd->chanlist_len; j++) {
201 unsigned short sample;
202 sample = fake_waveform(dev, CR_CHAN(cmd->chanlist[j]),
203 CR_RANGE(cmd->chanlist[j]),
204 devpriv->usec_current +
205 i * devpriv->scan_period +
206 j * devpriv->convert_period);
207 cfc_write_to_buffer(dev->read_subdev, sample);
211 devpriv->ai_count += i;
212 devpriv->usec_current += elapsed_time;
213 devpriv->usec_current %= devpriv->usec_period;
216 async->events |= COMEDI_CB_EOA;
218 mod_timer(&devpriv->timer, jiffies + 1);
220 comedi_event(dev, dev->read_subdev);
223 static int waveform_ai_cmdtest(struct comedi_device *dev,
224 struct comedi_subdevice *s,
225 struct comedi_cmd *cmd)
230 /* Step 1 : check if triggers are trivially valid */
232 err |= cfc_check_trigger_src(&cmd->start_src, TRIG_NOW);
233 err |= cfc_check_trigger_src(&cmd->scan_begin_src, TRIG_TIMER);
234 err |= cfc_check_trigger_src(&cmd->convert_src, TRIG_NOW | TRIG_TIMER);
235 err |= cfc_check_trigger_src(&cmd->scan_end_src, TRIG_COUNT);
236 err |= cfc_check_trigger_src(&cmd->stop_src, TRIG_COUNT | TRIG_NONE);
241 /* Step 2a : make sure trigger sources are unique */
243 err |= cfc_check_trigger_is_unique(cmd->convert_src);
244 err |= cfc_check_trigger_is_unique(cmd->stop_src);
246 /* Step 2b : and mutually compatible */
251 /* Step 3: check if arguments are trivially valid */
253 err |= cfc_check_trigger_arg_is(&cmd->start_arg, 0);
255 if (cmd->convert_src == TRIG_NOW)
256 err |= cfc_check_trigger_arg_is(&cmd->convert_arg, 0);
258 if (cmd->scan_begin_src == TRIG_TIMER) {
259 err |= cfc_check_trigger_arg_min(&cmd->scan_begin_arg,
261 if (cmd->convert_src == TRIG_TIMER)
262 err |= cfc_check_trigger_arg_min(&cmd->scan_begin_arg,
263 cmd->convert_arg * cmd->chanlist_len);
266 err |= cfc_check_trigger_arg_min(&cmd->chanlist_len, 1);
267 err |= cfc_check_trigger_arg_is(&cmd->scan_end_arg, cmd->chanlist_len);
269 if (cmd->stop_src == TRIG_COUNT)
270 err |= cfc_check_trigger_arg_min(&cmd->stop_arg, 1);
272 err |= cfc_check_trigger_arg_is(&cmd->stop_arg, 0);
277 /* step 4: fix up any arguments */
279 if (cmd->scan_begin_src == TRIG_TIMER) {
280 tmp = cmd->scan_begin_arg;
281 /* round to nearest microsec */
282 cmd->scan_begin_arg =
283 nano_per_micro * ((tmp +
284 (nano_per_micro / 2)) / nano_per_micro);
285 if (tmp != cmd->scan_begin_arg)
288 if (cmd->convert_src == TRIG_TIMER) {
289 tmp = cmd->convert_arg;
290 /* round to nearest microsec */
292 nano_per_micro * ((tmp +
293 (nano_per_micro / 2)) / nano_per_micro);
294 if (tmp != cmd->convert_arg)
304 static int waveform_ai_cmd(struct comedi_device *dev,
305 struct comedi_subdevice *s)
307 struct waveform_private *devpriv = dev->private;
308 struct comedi_cmd *cmd = &s->async->cmd;
310 if (cmd->flags & TRIG_RT) {
312 "commands at RT priority not supported in this driver");
316 devpriv->ai_count = 0;
317 devpriv->scan_period = cmd->scan_begin_arg / nano_per_micro;
319 if (cmd->convert_src == TRIG_NOW)
320 devpriv->convert_period = 0;
321 else if (cmd->convert_src == TRIG_TIMER)
322 devpriv->convert_period = cmd->convert_arg / nano_per_micro;
324 comedi_error(dev, "bug setting conversion period");
328 do_gettimeofday(&devpriv->last);
329 devpriv->usec_current = devpriv->last.tv_usec % devpriv->usec_period;
330 devpriv->usec_remainder = 0;
332 devpriv->timer.expires = jiffies + 1;
333 add_timer(&devpriv->timer);
337 static int waveform_ai_cancel(struct comedi_device *dev,
338 struct comedi_subdevice *s)
340 struct waveform_private *devpriv = dev->private;
342 del_timer_sync(&devpriv->timer);
346 static int waveform_ai_insn_read(struct comedi_device *dev,
347 struct comedi_subdevice *s,
348 struct comedi_insn *insn, unsigned int *data)
350 struct waveform_private *devpriv = dev->private;
351 int i, chan = CR_CHAN(insn->chanspec);
353 for (i = 0; i < insn->n; i++)
354 data[i] = devpriv->ao_loopbacks[chan];
359 static int waveform_ao_insn_write(struct comedi_device *dev,
360 struct comedi_subdevice *s,
361 struct comedi_insn *insn, unsigned int *data)
363 struct waveform_private *devpriv = dev->private;
364 int i, chan = CR_CHAN(insn->chanspec);
366 for (i = 0; i < insn->n; i++)
367 devpriv->ao_loopbacks[chan] = data[i];
372 static int waveform_attach(struct comedi_device *dev,
373 struct comedi_devconfig *it)
375 struct waveform_private *devpriv;
376 struct comedi_subdevice *s;
377 int amplitude = it->options[0];
378 int period = it->options[1];
382 devpriv = kzalloc(sizeof(*devpriv), GFP_KERNEL);
385 dev->private = 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");