1/*
2    comedi/drivers/comedi_test.c
3
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.
8
9    Copyright (C) 2002 Joachim Wuttke <Joachim.Wuttke@icn.siemens.de>
10    Copyright (C) 2002 Frank Mori Hess <fmhess@users.sourceforge.net>
11
12    COMEDI - Linux Control and Measurement Device Interface
13    Copyright (C) 2000 David A. Schleef <ds@schleef.org>
14
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.
19
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.
24*/
25/*
26Driver: comedi_test
27Description: generates fake waveforms
28Author: Joachim Wuttke <Joachim.Wuttke@icn.siemens.de>, Frank Mori Hess
29  <fmhess@users.sourceforge.net>, ds
30Devices:
31Status: works
32Updated: Sat, 16 Mar 2002 17:34:48 -0800
33
34This driver is mainly for testing purposes, but can also be used to
35generate sample waveforms on systems that don't have data acquisition
36hardware.
37
38Configuration options:
39  [0] - Amplitude in microvolts for fake waveforms (default 1 volt)
40  [1] - Period in microseconds for fake waveforms (default 0.1 sec)
41
42Generates a sawtooth wave on channel 0, square wave on channel 1, additional
43waveforms could be added to other channels (currently they return flatline
44zero volts).
45
46*/
47
48#include <linux/module.h>
49#include "../comedidev.h"
50
51#include <asm/div64.h>
52
53#include "comedi_fc.h"
54#include <linux/timer.h>
55
56#define N_CHANS 8
57
58/* Data unique to this driver */
59struct 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];
70};
71
72/* 1000 nanosec in a microsec */
73static const int nano_per_micro = 1000;
74
75/* fake analog input ranges */
76static const struct comedi_lrange waveform_ai_ranges = {
77	2, {
78		BIP_RANGE(10),
79		BIP_RANGE(5)
80	}
81};
82
83static unsigned short fake_sawtooth(struct comedi_device *dev,
84				    unsigned int range_index,
85				    unsigned long current_time)
86{
87	struct waveform_private *devpriv = dev->private;
88	struct comedi_subdevice *s = dev->read_subdev;
89	unsigned int offset = s->maxdata / 2;
90	u64 value;
91	const struct comedi_krange *krange =
92	    &s->range_table->range[range_index];
93	u64 binary_amplitude;
94
95	binary_amplitude = s->maxdata;
96	binary_amplitude *= devpriv->uvolt_amplitude;
97	do_div(binary_amplitude, krange->max - krange->min);
98
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 */
104
105	return offset + value;
106}
107
108static unsigned short fake_squarewave(struct comedi_device *dev,
109				      unsigned int range_index,
110				      unsigned long current_time)
111{
112	struct waveform_private *devpriv = dev->private;
113	struct comedi_subdevice *s = dev->read_subdev;
114	unsigned int offset = s->maxdata / 2;
115	u64 value;
116	const struct comedi_krange *krange =
117	    &s->range_table->range[range_index];
118	current_time %= devpriv->usec_period;
119
120	value = s->maxdata;
121	value *= devpriv->uvolt_amplitude;
122	do_div(value, krange->max - krange->min);
123
124	if (current_time < devpriv->usec_period / 2)
125		value *= -1;
126
127	return offset + value;
128}
129
130static unsigned short fake_flatline(struct comedi_device *dev,
131				    unsigned int range_index,
132				    unsigned long current_time)
133{
134	return dev->read_subdev->maxdata / 2;
135}
136
137/* generates a different waveform depending on what channel is read */
138static unsigned short fake_waveform(struct comedi_device *dev,
139				    unsigned int channel, unsigned int range,
140				    unsigned long current_time)
141{
142	enum {
143		SAWTOOTH_CHAN,
144		SQUARE_CHAN,
145	};
146	switch (channel) {
147	case SAWTOOTH_CHAN:
148		return fake_sawtooth(dev, range, current_time);
149	case SQUARE_CHAN:
150		return fake_squarewave(dev, range, current_time);
151	default:
152		break;
153	}
154
155	return fake_flatline(dev, range, current_time);
156}
157
158/*
159   This is the background routine used to generate arbitrary data.
160   It should run in the background; therefore it is scheduled by
161   a timer mechanism.
162*/
163static void waveform_ai_interrupt(unsigned long arg)
164{
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;
169	unsigned int i, j;
170	/* all times in microsec */
171	unsigned long elapsed_time;
172	unsigned int num_scans;
173	struct timeval now;
174	bool stopping = false;
175
176	do_gettimeofday(&now);
177
178	elapsed_time =
179	    1000000 * (now.tv_sec - devpriv->last.tv_sec) + now.tv_usec -
180	    devpriv->last.tv_usec;
181	devpriv->last = now;
182	num_scans =
183	    (devpriv->usec_remainder + elapsed_time) / devpriv->scan_period;
184	devpriv->usec_remainder =
185	    (devpriv->usec_remainder + elapsed_time) % devpriv->scan_period;
186
187	if (cmd->stop_src == TRIG_COUNT) {
188		unsigned int remaining = cmd->stop_arg - devpriv->ai_count;
189
190		if (num_scans >= remaining) {
191			/* about to finish */
192			num_scans = remaining;
193			stopping = true;
194		}
195	}
196
197	for (i = 0; i < num_scans; i++) {
198		for (j = 0; j < cmd->chanlist_len; j++) {
199			unsigned short sample;
200
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);
207		}
208	}
209
210	devpriv->ai_count += i;
211	devpriv->usec_current += elapsed_time;
212	devpriv->usec_current %= devpriv->usec_period;
213
214	if (stopping)
215		async->events |= COMEDI_CB_EOA;
216	else
217		mod_timer(&devpriv->timer, jiffies + 1);
218
219	comedi_event(dev, dev->read_subdev);
220}
221
222static int waveform_ai_cmdtest(struct comedi_device *dev,
223			       struct comedi_subdevice *s,
224			       struct comedi_cmd *cmd)
225{
226	int err = 0;
227	unsigned int arg;
228
229	/* Step 1 : check if triggers are trivially valid */
230
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);
236
237	if (err)
238		return 1;
239
240	/* Step 2a : make sure trigger sources are unique */
241
242	err |= cfc_check_trigger_is_unique(cmd->convert_src);
243	err |= cfc_check_trigger_is_unique(cmd->stop_src);
244
245	/* Step 2b : and mutually compatible */
246
247	if (err)
248		return 2;
249
250	/* Step 3: check if arguments are trivially valid */
251
252	err |= cfc_check_trigger_arg_is(&cmd->start_arg, 0);
253
254	if (cmd->convert_src == TRIG_NOW)
255		err |= cfc_check_trigger_arg_is(&cmd->convert_arg, 0);
256
257	if (cmd->scan_begin_src == TRIG_TIMER) {
258		err |= cfc_check_trigger_arg_min(&cmd->scan_begin_arg,
259						 nano_per_micro);
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);
263	}
264
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);
267
268	if (cmd->stop_src == TRIG_COUNT)
269		err |= cfc_check_trigger_arg_min(&cmd->stop_arg, 1);
270	else	/* TRIG_NONE */
271		err |= cfc_check_trigger_arg_is(&cmd->stop_arg, 0);
272
273	if (err)
274		return 3;
275
276	/* step 4: fix up any arguments */
277
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);
284	}
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);
291	}
292
293	if (err)
294		return 4;
295
296	return 0;
297}
298
299static int waveform_ai_cmd(struct comedi_device *dev,
300			   struct comedi_subdevice *s)
301{
302	struct waveform_private *devpriv = dev->private;
303	struct comedi_cmd *cmd = &s->async->cmd;
304
305	if (cmd->flags & CMDF_PRIORITY) {
306		dev_err(dev->class_dev,
307			"commands at RT priority not supported in this driver\n");
308		return -1;
309	}
310
311	devpriv->ai_count = 0;
312	devpriv->scan_period = cmd->scan_begin_arg / nano_per_micro;
313
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;
318
319	do_gettimeofday(&devpriv->last);
320	devpriv->usec_current = devpriv->last.tv_usec % devpriv->usec_period;
321	devpriv->usec_remainder = 0;
322
323	devpriv->timer.expires = jiffies + 1;
324	add_timer(&devpriv->timer);
325	return 0;
326}
327
328static int waveform_ai_cancel(struct comedi_device *dev,
329			      struct comedi_subdevice *s)
330{
331	struct waveform_private *devpriv = dev->private;
332
333	del_timer_sync(&devpriv->timer);
334	return 0;
335}
336
337static int waveform_ai_insn_read(struct comedi_device *dev,
338				 struct comedi_subdevice *s,
339				 struct comedi_insn *insn, unsigned int *data)
340{
341	struct waveform_private *devpriv = dev->private;
342	int i, chan = CR_CHAN(insn->chanspec);
343
344	for (i = 0; i < insn->n; i++)
345		data[i] = devpriv->ao_loopbacks[chan];
346
347	return insn->n;
348}
349
350static int waveform_ao_insn_write(struct comedi_device *dev,
351				  struct comedi_subdevice *s,
352				  struct comedi_insn *insn, unsigned int *data)
353{
354	struct waveform_private *devpriv = dev->private;
355	int i, chan = CR_CHAN(insn->chanspec);
356
357	for (i = 0; i < insn->n; i++)
358		devpriv->ao_loopbacks[chan] = data[i];
359
360	return insn->n;
361}
362
363static int waveform_attach(struct comedi_device *dev,
364			   struct comedi_devconfig *it)
365{
366	struct waveform_private *devpriv;
367	struct comedi_subdevice *s;
368	int amplitude = it->options[0];
369	int period = it->options[1];
370	int i;
371	int ret;
372
373	devpriv = comedi_alloc_devpriv(dev, sizeof(*devpriv));
374	if (!devpriv)
375		return -ENOMEM;
376
377	/* set default amplitude and period */
378	if (amplitude <= 0)
379		amplitude = 1000000;	/* 1 volt */
380	if (period <= 0)
381		period = 100000;	/* 0.1 sec */
382
383	devpriv->uvolt_amplitude = amplitude;
384	devpriv->usec_period = period;
385
386	ret = comedi_alloc_subdevices(dev, 2);
387	if (ret)
388		return ret;
389
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;
395	s->n_chan = N_CHANS;
396	s->maxdata = 0xffff;
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;
403
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;
409	s->n_chan = N_CHANS;
410	s->maxdata = 0xffff;
411	s->range_table = &waveform_ai_ranges;
412	s->insn_write = waveform_ao_insn_write;
413
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;
417
418	init_timer(&devpriv->timer);
419	devpriv->timer.function = waveform_ai_interrupt;
420	devpriv->timer.data = (unsigned long)dev;
421
422	dev_info(dev->class_dev,
423		 "%s: %i microvolt, %li microsecond waveform attached\n",
424		 dev->board_name,
425		 devpriv->uvolt_amplitude, devpriv->usec_period);
426
427	return 0;
428}
429
430static void waveform_detach(struct comedi_device *dev)
431{
432	struct waveform_private *devpriv = dev->private;
433
434	if (devpriv)
435		waveform_ai_cancel(dev, dev->read_subdev);
436}
437
438static struct comedi_driver waveform_driver = {
439	.driver_name	= "comedi_test",
440	.module		= THIS_MODULE,
441	.attach		= waveform_attach,
442	.detach		= waveform_detach,
443};
444module_comedi_driver(waveform_driver);
445
446MODULE_AUTHOR("Comedi http://www.comedi.org");
447MODULE_DESCRIPTION("Comedi low-level driver");
448MODULE_LICENSE("GPL");
449