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 <linux/timer.h>
54 #include <linux/ktime.h>
58 enum waveform_state_bits {
59 WAVEFORM_AI_RUNNING = 0
62 /* Data unique to this driver */
63 struct waveform_private {
64 struct timer_list timer;
65 ktime_t 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 state_bits;
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 = {
87 static unsigned short fake_sawtooth(struct comedi_device *dev,
88 unsigned int range_index,
89 unsigned long current_time)
91 struct waveform_private *devpriv = dev->private;
92 struct comedi_subdevice *s = dev->read_subdev;
93 unsigned int offset = s->maxdata / 2;
95 const struct comedi_krange *krange =
96 &s->range_table->range[range_index];
99 binary_amplitude = s->maxdata;
100 binary_amplitude *= devpriv->uvolt_amplitude;
101 do_div(binary_amplitude, krange->max - krange->min);
103 current_time %= devpriv->usec_period;
104 value = current_time;
105 value *= binary_amplitude * 2;
106 do_div(value, devpriv->usec_period);
107 value -= binary_amplitude; /* get rid of sawtooth's dc offset */
109 return offset + value;
112 static unsigned short fake_squarewave(struct comedi_device *dev,
113 unsigned int range_index,
114 unsigned long current_time)
116 struct waveform_private *devpriv = dev->private;
117 struct comedi_subdevice *s = dev->read_subdev;
118 unsigned int offset = s->maxdata / 2;
120 const struct comedi_krange *krange =
121 &s->range_table->range[range_index];
122 current_time %= devpriv->usec_period;
125 value *= devpriv->uvolt_amplitude;
126 do_div(value, krange->max - krange->min);
128 if (current_time < devpriv->usec_period / 2)
131 return offset + value;
134 static unsigned short fake_flatline(struct comedi_device *dev,
135 unsigned int range_index,
136 unsigned long current_time)
138 return dev->read_subdev->maxdata / 2;
141 /* generates a different waveform depending on what channel is read */
142 static unsigned short fake_waveform(struct comedi_device *dev,
143 unsigned int channel, unsigned int range,
144 unsigned long current_time)
152 return fake_sawtooth(dev, range, current_time);
154 return fake_squarewave(dev, range, current_time);
159 return fake_flatline(dev, range, current_time);
163 This is the background routine used to generate arbitrary data.
164 It should run in the background; therefore it is scheduled by
167 static void waveform_ai_interrupt(unsigned long arg)
169 struct comedi_device *dev = (struct comedi_device *)arg;
170 struct waveform_private *devpriv = dev->private;
171 struct comedi_subdevice *s = dev->read_subdev;
172 struct comedi_async *async = s->async;
173 struct comedi_cmd *cmd = &async->cmd;
175 /* all times in microsec */
176 unsigned long elapsed_time;
177 unsigned int num_scans;
180 /* check command is still active */
181 if (!test_bit(WAVEFORM_AI_RUNNING, &devpriv->state_bits))
186 elapsed_time = ktime_to_us(ktime_sub(now, devpriv->last));
189 (devpriv->usec_remainder + elapsed_time) / devpriv->scan_period;
190 devpriv->usec_remainder =
191 (devpriv->usec_remainder + elapsed_time) % devpriv->scan_period;
193 num_scans = comedi_nscans_left(s, num_scans);
194 for (i = 0; i < num_scans; i++) {
195 for (j = 0; j < cmd->chanlist_len; j++) {
196 unsigned short sample;
198 sample = fake_waveform(dev, CR_CHAN(cmd->chanlist[j]),
199 CR_RANGE(cmd->chanlist[j]),
200 devpriv->usec_current +
201 i * devpriv->scan_period +
202 j * devpriv->convert_period);
203 comedi_buf_write_samples(s, &sample, 1);
207 devpriv->usec_current += elapsed_time;
208 devpriv->usec_current %= devpriv->usec_period;
210 if (cmd->stop_src == TRIG_COUNT && async->scans_done >= cmd->stop_arg)
211 async->events |= COMEDI_CB_EOA;
213 mod_timer(&devpriv->timer, jiffies + 1);
215 comedi_handle_events(dev, s);
218 static int waveform_ai_cmdtest(struct comedi_device *dev,
219 struct comedi_subdevice *s,
220 struct comedi_cmd *cmd)
225 /* Step 1 : check if triggers are trivially valid */
227 err |= comedi_check_trigger_src(&cmd->start_src, TRIG_NOW);
228 err |= comedi_check_trigger_src(&cmd->scan_begin_src, TRIG_TIMER);
229 err |= comedi_check_trigger_src(&cmd->convert_src,
230 TRIG_NOW | TRIG_TIMER);
231 err |= comedi_check_trigger_src(&cmd->scan_end_src, TRIG_COUNT);
232 err |= comedi_check_trigger_src(&cmd->stop_src, TRIG_COUNT | TRIG_NONE);
237 /* Step 2a : make sure trigger sources are unique */
239 err |= comedi_check_trigger_is_unique(cmd->convert_src);
240 err |= comedi_check_trigger_is_unique(cmd->stop_src);
242 /* Step 2b : and mutually compatible */
247 /* Step 3: check if arguments are trivially valid */
249 err |= comedi_check_trigger_arg_is(&cmd->start_arg, 0);
251 if (cmd->convert_src == TRIG_NOW)
252 err |= comedi_check_trigger_arg_is(&cmd->convert_arg, 0);
254 if (cmd->scan_begin_src == TRIG_TIMER) {
255 err |= comedi_check_trigger_arg_min(&cmd->scan_begin_arg,
257 if (cmd->convert_src == TRIG_TIMER) {
258 err |= comedi_check_trigger_arg_min(&cmd->
265 err |= comedi_check_trigger_arg_min(&cmd->chanlist_len, 1);
266 err |= comedi_check_trigger_arg_is(&cmd->scan_end_arg,
269 if (cmd->stop_src == TRIG_COUNT)
270 err |= comedi_check_trigger_arg_min(&cmd->stop_arg, 1);
272 err |= comedi_check_trigger_arg_is(&cmd->stop_arg, 0);
277 /* step 4: fix up any arguments */
279 if (cmd->scan_begin_src == TRIG_TIMER) {
280 arg = cmd->scan_begin_arg;
281 /* round to nearest microsec */
282 arg = nano_per_micro *
283 ((arg + (nano_per_micro / 2)) / nano_per_micro);
284 err |= comedi_check_trigger_arg_is(&cmd->scan_begin_arg, arg);
286 if (cmd->convert_src == TRIG_TIMER) {
287 arg = cmd->convert_arg;
288 /* round to nearest microsec */
289 arg = nano_per_micro *
290 ((arg + (nano_per_micro / 2)) / nano_per_micro);
291 err |= comedi_check_trigger_arg_is(&cmd->convert_arg, arg);
300 static int waveform_ai_cmd(struct comedi_device *dev,
301 struct comedi_subdevice *s)
303 struct waveform_private *devpriv = dev->private;
304 struct comedi_cmd *cmd = &s->async->cmd;
306 if (cmd->flags & CMDF_PRIORITY) {
307 dev_err(dev->class_dev,
308 "commands at RT priority not supported in this driver\n");
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 devpriv->last = ktime_get();
320 devpriv->usec_current =
321 ((u32)ktime_to_us(devpriv->last)) % devpriv->usec_period;
322 devpriv->usec_remainder = 0;
324 devpriv->timer.expires = jiffies + 1;
325 /* mark command as active */
326 smp_mb__before_atomic();
327 set_bit(WAVEFORM_AI_RUNNING, &devpriv->state_bits);
328 smp_mb__after_atomic();
329 add_timer(&devpriv->timer);
333 static int waveform_ai_cancel(struct comedi_device *dev,
334 struct comedi_subdevice *s)
336 struct waveform_private *devpriv = dev->private;
338 /* mark command as no longer active */
339 clear_bit(WAVEFORM_AI_RUNNING, &devpriv->state_bits);
340 smp_mb__after_atomic();
341 /* cannot call del_timer_sync() as may be called from timer routine */
342 del_timer(&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 = comedi_alloc_devpriv(dev, sizeof(*devpriv));
386 /* set default amplitude and period */
388 amplitude = 1000000; /* 1 volt */
390 period = 100000; /* 0.1 sec */
392 devpriv->uvolt_amplitude = amplitude;
393 devpriv->usec_period = period;
395 ret = comedi_alloc_subdevices(dev, 2);
399 s = &dev->subdevices[0];
400 dev->read_subdev = s;
401 /* analog input subdevice */
402 s->type = COMEDI_SUBD_AI;
403 s->subdev_flags = SDF_READABLE | SDF_GROUND | SDF_CMD_READ;
406 s->range_table = &waveform_ai_ranges;
407 s->len_chanlist = s->n_chan * 2;
408 s->insn_read = waveform_ai_insn_read;
409 s->do_cmd = waveform_ai_cmd;
410 s->do_cmdtest = waveform_ai_cmdtest;
411 s->cancel = waveform_ai_cancel;
413 s = &dev->subdevices[1];
414 dev->write_subdev = s;
415 /* analog output subdevice (loopback) */
416 s->type = COMEDI_SUBD_AO;
417 s->subdev_flags = SDF_WRITABLE | SDF_GROUND;
420 s->range_table = &waveform_ai_ranges;
421 s->insn_write = waveform_ao_insn_write;
423 /* Our default loopback value is just a 0V flatline */
424 for (i = 0; i < s->n_chan; i++)
425 devpriv->ao_loopbacks[i] = s->maxdata / 2;
427 setup_timer(&devpriv->timer, waveform_ai_interrupt,
430 dev_info(dev->class_dev,
431 "%s: %i microvolt, %li microsecond waveform attached\n",
433 devpriv->uvolt_amplitude, devpriv->usec_period);
438 static void waveform_detach(struct comedi_device *dev)
440 struct waveform_private *devpriv = dev->private;
443 del_timer_sync(&devpriv->timer);
446 static struct comedi_driver waveform_driver = {
447 .driver_name = "comedi_test",
448 .module = THIS_MODULE,
449 .attach = waveform_attach,
450 .detach = waveform_detach,
452 module_comedi_driver(waveform_driver);
454 MODULE_AUTHOR("Comedi http://www.comedi.org");
455 MODULE_DESCRIPTION("Comedi low-level driver");
456 MODULE_LICENSE("GPL");