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 = {
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);
150 return fake_squarewave(dev, range, current_time);
155 return fake_flatline(dev, range, current_time);
159 This is the background routine used to generate arbitrary data.
160 It should run in the background; therefore it is scheduled by
163 static void waveform_ai_interrupt(unsigned long arg)
165 struct comedi_device *dev = (struct comedi_device *)arg;
166 struct waveform_private *devpriv = dev->private;
167 struct comedi_async *async = dev->read_subdev->async;
168 struct comedi_cmd *cmd = &async->cmd;
170 /* all times in microsec */
171 unsigned long elapsed_time;
172 unsigned int num_scans;
174 bool stopping = false;
176 do_gettimeofday(&now);
179 1000000 * (now.tv_sec - devpriv->last.tv_sec) + now.tv_usec -
180 devpriv->last.tv_usec;
183 (devpriv->usec_remainder + elapsed_time) / devpriv->scan_period;
184 devpriv->usec_remainder =
185 (devpriv->usec_remainder + elapsed_time) % devpriv->scan_period;
187 if (cmd->stop_src == TRIG_COUNT) {
188 unsigned int remaining = cmd->stop_arg - devpriv->ai_count;
190 if (num_scans >= remaining) {
191 /* about to finish */
192 num_scans = remaining;
197 for (i = 0; i < num_scans; i++) {
198 for (j = 0; j < cmd->chanlist_len; j++) {
199 unsigned short sample;
201 sample = fake_waveform(dev, CR_CHAN(cmd->chanlist[j]),
202 CR_RANGE(cmd->chanlist[j]),
203 devpriv->usec_current +
204 i * devpriv->scan_period +
205 j * devpriv->convert_period);
206 cfc_write_to_buffer(dev->read_subdev, sample);
210 devpriv->ai_count += i;
211 devpriv->usec_current += elapsed_time;
212 devpriv->usec_current %= devpriv->usec_period;
215 async->events |= COMEDI_CB_EOA;
217 mod_timer(&devpriv->timer, jiffies + 1);
219 comedi_event(dev, dev->read_subdev);
222 static int waveform_ai_cmdtest(struct comedi_device *dev,
223 struct comedi_subdevice *s,
224 struct comedi_cmd *cmd)
229 /* Step 1 : check if triggers are trivially valid */
231 err |= cfc_check_trigger_src(&cmd->start_src, TRIG_NOW);
232 err |= cfc_check_trigger_src(&cmd->scan_begin_src, TRIG_TIMER);
233 err |= cfc_check_trigger_src(&cmd->convert_src, TRIG_NOW | TRIG_TIMER);
234 err |= cfc_check_trigger_src(&cmd->scan_end_src, TRIG_COUNT);
235 err |= cfc_check_trigger_src(&cmd->stop_src, TRIG_COUNT | TRIG_NONE);
240 /* Step 2a : make sure trigger sources are unique */
242 err |= cfc_check_trigger_is_unique(cmd->convert_src);
243 err |= cfc_check_trigger_is_unique(cmd->stop_src);
245 /* Step 2b : and mutually compatible */
250 /* Step 3: check if arguments are trivially valid */
252 err |= cfc_check_trigger_arg_is(&cmd->start_arg, 0);
254 if (cmd->convert_src == TRIG_NOW)
255 err |= cfc_check_trigger_arg_is(&cmd->convert_arg, 0);
257 if (cmd->scan_begin_src == TRIG_TIMER) {
258 err |= cfc_check_trigger_arg_min(&cmd->scan_begin_arg,
260 if (cmd->convert_src == TRIG_TIMER)
261 err |= cfc_check_trigger_arg_min(&cmd->scan_begin_arg,
262 cmd->convert_arg * cmd->chanlist_len);
265 err |= cfc_check_trigger_arg_min(&cmd->chanlist_len, 1);
266 err |= cfc_check_trigger_arg_is(&cmd->scan_end_arg, cmd->chanlist_len);
268 if (cmd->stop_src == TRIG_COUNT)
269 err |= cfc_check_trigger_arg_min(&cmd->stop_arg, 1);
271 err |= cfc_check_trigger_arg_is(&cmd->stop_arg, 0);
276 /* step 4: fix up any arguments */
278 if (cmd->scan_begin_src == TRIG_TIMER) {
279 arg = cmd->scan_begin_arg;
280 /* round to nearest microsec */
281 arg = nano_per_micro *
282 ((arg + (nano_per_micro / 2)) / nano_per_micro);
283 err |= cfc_check_trigger_arg_is(&cmd->scan_begin_arg, arg);
285 if (cmd->convert_src == TRIG_TIMER) {
286 arg = cmd->convert_arg;
287 /* round to nearest microsec */
288 arg = nano_per_micro *
289 ((arg + (nano_per_micro / 2)) / nano_per_micro);
290 err |= cfc_check_trigger_arg_is(&cmd->convert_arg, arg);
299 static int waveform_ai_cmd(struct comedi_device *dev,
300 struct comedi_subdevice *s)
302 struct waveform_private *devpriv = dev->private;
303 struct comedi_cmd *cmd = &s->async->cmd;
305 if (cmd->flags & TRIG_RT) {
306 dev_err(dev->class_dev,
307 "commands at RT priority not supported in this driver\n");
311 devpriv->ai_count = 0;
312 devpriv->scan_period = cmd->scan_begin_arg / nano_per_micro;
314 if (cmd->convert_src == TRIG_NOW)
315 devpriv->convert_period = 0;
316 else /* TRIG_TIMER */
317 devpriv->convert_period = cmd->convert_arg / nano_per_micro;
319 do_gettimeofday(&devpriv->last);
320 devpriv->usec_current = devpriv->last.tv_usec % devpriv->usec_period;
321 devpriv->usec_remainder = 0;
323 devpriv->timer.expires = jiffies + 1;
324 add_timer(&devpriv->timer);
328 static int waveform_ai_cancel(struct comedi_device *dev,
329 struct comedi_subdevice *s)
331 struct waveform_private *devpriv = dev->private;
333 del_timer_sync(&devpriv->timer);
337 static int waveform_ai_insn_read(struct comedi_device *dev,
338 struct comedi_subdevice *s,
339 struct comedi_insn *insn, unsigned int *data)
341 struct waveform_private *devpriv = dev->private;
342 int i, chan = CR_CHAN(insn->chanspec);
344 for (i = 0; i < insn->n; i++)
345 data[i] = devpriv->ao_loopbacks[chan];
350 static int waveform_ao_insn_write(struct comedi_device *dev,
351 struct comedi_subdevice *s,
352 struct comedi_insn *insn, unsigned int *data)
354 struct waveform_private *devpriv = dev->private;
355 int i, chan = CR_CHAN(insn->chanspec);
357 for (i = 0; i < insn->n; i++)
358 devpriv->ao_loopbacks[chan] = data[i];
363 static int waveform_attach(struct comedi_device *dev,
364 struct comedi_devconfig *it)
366 struct waveform_private *devpriv;
367 struct comedi_subdevice *s;
368 int amplitude = it->options[0];
369 int period = it->options[1];
373 devpriv = comedi_alloc_devpriv(dev, sizeof(*devpriv));
377 /* set default amplitude and period */
379 amplitude = 1000000; /* 1 volt */
381 period = 100000; /* 0.1 sec */
383 devpriv->uvolt_amplitude = amplitude;
384 devpriv->usec_period = period;
386 ret = comedi_alloc_subdevices(dev, 2);
390 s = &dev->subdevices[0];
391 dev->read_subdev = s;
392 /* analog input subdevice */
393 s->type = COMEDI_SUBD_AI;
394 s->subdev_flags = SDF_READABLE | SDF_GROUND | SDF_CMD_READ;
397 s->range_table = &waveform_ai_ranges;
398 s->len_chanlist = s->n_chan * 2;
399 s->insn_read = waveform_ai_insn_read;
400 s->do_cmd = waveform_ai_cmd;
401 s->do_cmdtest = waveform_ai_cmdtest;
402 s->cancel = waveform_ai_cancel;
404 s = &dev->subdevices[1];
405 dev->write_subdev = s;
406 /* analog output subdevice (loopback) */
407 s->type = COMEDI_SUBD_AO;
408 s->subdev_flags = SDF_WRITEABLE | SDF_GROUND;
411 s->range_table = &waveform_ai_ranges;
412 s->insn_write = waveform_ao_insn_write;
414 /* Our default loopback value is just a 0V flatline */
415 for (i = 0; i < s->n_chan; i++)
416 devpriv->ao_loopbacks[i] = s->maxdata / 2;
418 init_timer(&(devpriv->timer));
419 devpriv->timer.function = waveform_ai_interrupt;
420 devpriv->timer.data = (unsigned long)dev;
422 dev_info(dev->class_dev,
423 "%s: %i microvolt, %li microsecond waveform attached\n",
425 devpriv->uvolt_amplitude, devpriv->usec_period);
430 static void waveform_detach(struct comedi_device *dev)
432 struct waveform_private *devpriv = dev->private;
435 waveform_ai_cancel(dev, dev->read_subdev);
438 static struct comedi_driver waveform_driver = {
439 .driver_name = "comedi_test",
440 .module = THIS_MODULE,
441 .attach = waveform_attach,
442 .detach = waveform_detach,
444 module_comedi_driver(waveform_driver);
446 MODULE_AUTHOR("Comedi http://www.comedi.org");
447 MODULE_DESCRIPTION("Comedi low-level driver");
448 MODULE_LICENSE("GPL");