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comedi/drivers/comedi_test.c
Generates fake waveform signals that can be read through
the command interface. It does _not_ read from any board;
it just generates deterministic waveforms.
Useful for various testing purposes.
Copyright (C) 2002 Joachim Wuttke <Joachim.Wuttke@icn.siemens.de>
Copyright (C) 2002 Frank Mori Hess <fmhess@users.sourceforge.net>
COMEDI - Linux Control and Measurement Device Interface
Copyright (C) 2000 David A. Schleef <ds@schleef.org>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
*/
/*
Driver: comedi_test
Description: generates fake waveforms
Author: Joachim Wuttke <Joachim.Wuttke@icn.siemens.de>, Frank Mori Hess
<fmhess@users.sourceforge.net>, ds
Devices:
Status: works
Updated: Sat, 16 Mar 2002 17:34:48 -0800
This driver is mainly for testing purposes, but can also be used to
generate sample waveforms on systems that don't have data acquisition
hardware.
Configuration options:
[0] - Amplitude in microvolts for fake waveforms (default 1 volt)
[1] - Period in microseconds for fake waveforms (default 0.1 sec)
Generates a sawtooth wave on channel 0, square wave on channel 1, additional
waveforms could be added to other channels (currently they return flatline
zero volts).
*/
#include <linux/module.h>
#include "../comedidev.h"
#include <asm/div64.h>
#include "comedi_fc.h"
#include <linux/timer.h>
#define N_CHANS 8
/* Data unique to this driver */
struct waveform_private {
struct timer_list timer;
struct timeval last; /* time last timer interrupt occurred */
unsigned int uvolt_amplitude; /* waveform amplitude in microvolts */
unsigned long usec_period; /* waveform period in microseconds */
unsigned long usec_current; /* current time (mod waveform period) */
unsigned long usec_remainder; /* usec since last scan */
unsigned long ai_count; /* number of conversions remaining */
unsigned int scan_period; /* scan period in usec */
unsigned int convert_period; /* conversion period in usec */
unsigned int ao_loopbacks[N_CHANS];
};
/* 1000 nanosec in a microsec */
static const int nano_per_micro = 1000;
/* fake analog input ranges */
static const struct comedi_lrange waveform_ai_ranges = {
2, {
BIP_RANGE(10),
BIP_RANGE(5)
}
};
static unsigned short fake_sawtooth(struct comedi_device *dev,
unsigned int range_index,
unsigned long current_time)
{
struct waveform_private *devpriv = dev->private;
struct comedi_subdevice *s = dev->read_subdev;
unsigned int offset = s->maxdata / 2;
u64 value;
const struct comedi_krange *krange =
&s->range_table->range[range_index];
u64 binary_amplitude;
binary_amplitude = s->maxdata;
binary_amplitude *= devpriv->uvolt_amplitude;
do_div(binary_amplitude, krange->max - krange->min);
current_time %= devpriv->usec_period;
value = current_time;
value *= binary_amplitude * 2;
do_div(value, devpriv->usec_period);
value -= binary_amplitude; /* get rid of sawtooth's dc offset */
return offset + value;
}
static unsigned short fake_squarewave(struct comedi_device *dev,
unsigned int range_index,
unsigned long current_time)
{
struct waveform_private *devpriv = dev->private;
struct comedi_subdevice *s = dev->read_subdev;
unsigned int offset = s->maxdata / 2;
u64 value;
const struct comedi_krange *krange =
&s->range_table->range[range_index];
current_time %= devpriv->usec_period;
value = s->maxdata;
value *= devpriv->uvolt_amplitude;
do_div(value, krange->max - krange->min);
if (current_time < devpriv->usec_period / 2)
value *= -1;
return offset + value;
}
static unsigned short fake_flatline(struct comedi_device *dev,
unsigned int range_index,
unsigned long current_time)
{
return dev->read_subdev->maxdata / 2;
}
/* generates a different waveform depending on what channel is read */
static unsigned short fake_waveform(struct comedi_device *dev,
unsigned int channel, unsigned int range,
unsigned long current_time)
{
enum {
SAWTOOTH_CHAN,
SQUARE_CHAN,
};
switch (channel) {
case SAWTOOTH_CHAN:
return fake_sawtooth(dev, range, current_time);
case SQUARE_CHAN:
return fake_squarewave(dev, range, current_time);
default:
break;
}
return fake_flatline(dev, range, current_time);
}
/*
This is the background routine used to generate arbitrary data.
It should run in the background; therefore it is scheduled by
a timer mechanism.
*/
static void waveform_ai_interrupt(unsigned long arg)
{
struct comedi_device *dev = (struct comedi_device *)arg;
struct waveform_private *devpriv = dev->private;
struct comedi_async *async = dev->read_subdev->async;
struct comedi_cmd *cmd = &async->cmd;
unsigned int i, j;
/* all times in microsec */
unsigned long elapsed_time;
unsigned int num_scans;
struct timeval now;
bool stopping = false;
do_gettimeofday(&now);
elapsed_time =
1000000 * (now.tv_sec - devpriv->last.tv_sec) + now.tv_usec -
devpriv->last.tv_usec;
devpriv->last = now;
num_scans =
(devpriv->usec_remainder + elapsed_time) / devpriv->scan_period;
devpriv->usec_remainder =
(devpriv->usec_remainder + elapsed_time) % devpriv->scan_period;
if (cmd->stop_src == TRIG_COUNT) {
unsigned int remaining = cmd->stop_arg - devpriv->ai_count;
if (num_scans >= remaining) {
/* about to finish */
num_scans = remaining;
stopping = true;
}
}
for (i = 0; i < num_scans; i++) {
for (j = 0; j < cmd->chanlist_len; j++) {
unsigned short sample;
sample = fake_waveform(dev, CR_CHAN(cmd->chanlist[j]),
CR_RANGE(cmd->chanlist[j]),
devpriv->usec_current +
i * devpriv->scan_period +
j * devpriv->convert_period);
cfc_write_to_buffer(dev->read_subdev, sample);
}
}
devpriv->ai_count += i;
devpriv->usec_current += elapsed_time;
devpriv->usec_current %= devpriv->usec_period;
if (stopping)
async->events |= COMEDI_CB_EOA;
else
mod_timer(&devpriv->timer, jiffies + 1);
comedi_event(dev, dev->read_subdev);
}
static int waveform_ai_cmdtest(struct comedi_device *dev,
struct comedi_subdevice *s,
struct comedi_cmd *cmd)
{
int err = 0;
unsigned int arg;
/* Step 1 : check if triggers are trivially valid */
err |= cfc_check_trigger_src(&cmd->start_src, TRIG_NOW);
err |= cfc_check_trigger_src(&cmd->scan_begin_src, TRIG_TIMER);
err |= cfc_check_trigger_src(&cmd->convert_src, TRIG_NOW | TRIG_TIMER);
err |= cfc_check_trigger_src(&cmd->scan_end_src, TRIG_COUNT);
err |= cfc_check_trigger_src(&cmd->stop_src, TRIG_COUNT | TRIG_NONE);
if (err)
return 1;
/* Step 2a : make sure trigger sources are unique */
err |= cfc_check_trigger_is_unique(cmd->convert_src);
err |= cfc_check_trigger_is_unique(cmd->stop_src);
/* Step 2b : and mutually compatible */
if (err)
return 2;
/* Step 3: check if arguments are trivially valid */
err |= cfc_check_trigger_arg_is(&cmd->start_arg, 0);
if (cmd->convert_src == TRIG_NOW)
err |= cfc_check_trigger_arg_is(&cmd->convert_arg, 0);
if (cmd->scan_begin_src == TRIG_TIMER) {
err |= cfc_check_trigger_arg_min(&cmd->scan_begin_arg,
nano_per_micro);
if (cmd->convert_src == TRIG_TIMER)
err |= cfc_check_trigger_arg_min(&cmd->scan_begin_arg,
cmd->convert_arg * cmd->chanlist_len);
}
err |= cfc_check_trigger_arg_min(&cmd->chanlist_len, 1);
err |= cfc_check_trigger_arg_is(&cmd->scan_end_arg, cmd->chanlist_len);
if (cmd->stop_src == TRIG_COUNT)
err |= cfc_check_trigger_arg_min(&cmd->stop_arg, 1);
else /* TRIG_NONE */
err |= cfc_check_trigger_arg_is(&cmd->stop_arg, 0);
if (err)
return 3;
/* step 4: fix up any arguments */
if (cmd->scan_begin_src == TRIG_TIMER) {
arg = cmd->scan_begin_arg;
/* round to nearest microsec */
arg = nano_per_micro *
((arg + (nano_per_micro / 2)) / nano_per_micro);
err |= cfc_check_trigger_arg_is(&cmd->scan_begin_arg, arg);
}
if (cmd->convert_src == TRIG_TIMER) {
arg = cmd->convert_arg;
/* round to nearest microsec */
arg = nano_per_micro *
((arg + (nano_per_micro / 2)) / nano_per_micro);
err |= cfc_check_trigger_arg_is(&cmd->convert_arg, arg);
}
if (err)
return 4;
return 0;
}
static int waveform_ai_cmd(struct comedi_device *dev,
struct comedi_subdevice *s)
{
struct waveform_private *devpriv = dev->private;
struct comedi_cmd *cmd = &s->async->cmd;
if (cmd->flags & CMDF_PRIORITY) {
dev_err(dev->class_dev,
"commands at RT priority not supported in this driver\n");
return -1;
}
devpriv->ai_count = 0;
devpriv->scan_period = cmd->scan_begin_arg / nano_per_micro;
if (cmd->convert_src == TRIG_NOW)
devpriv->convert_period = 0;
else /* TRIG_TIMER */
devpriv->convert_period = cmd->convert_arg / nano_per_micro;
do_gettimeofday(&devpriv->last);
devpriv->usec_current = devpriv->last.tv_usec % devpriv->usec_period;
devpriv->usec_remainder = 0;
devpriv->timer.expires = jiffies + 1;
add_timer(&devpriv->timer);
return 0;
}
static int waveform_ai_cancel(struct comedi_device *dev,
struct comedi_subdevice *s)
{
struct waveform_private *devpriv = dev->private;
del_timer_sync(&devpriv->timer);
return 0;
}
static int waveform_ai_insn_read(struct comedi_device *dev,
struct comedi_subdevice *s,
struct comedi_insn *insn, unsigned int *data)
{
struct waveform_private *devpriv = dev->private;
int i, chan = CR_CHAN(insn->chanspec);
for (i = 0; i < insn->n; i++)
data[i] = devpriv->ao_loopbacks[chan];
return insn->n;
}
static int waveform_ao_insn_write(struct comedi_device *dev,
struct comedi_subdevice *s,
struct comedi_insn *insn, unsigned int *data)
{
struct waveform_private *devpriv = dev->private;
int i, chan = CR_CHAN(insn->chanspec);
for (i = 0; i < insn->n; i++)
devpriv->ao_loopbacks[chan] = data[i];
return insn->n;
}
static int waveform_attach(struct comedi_device *dev,
struct comedi_devconfig *it)
{
struct waveform_private *devpriv;
struct comedi_subdevice *s;
int amplitude = it->options[0];
int period = it->options[1];
int i;
int ret;
devpriv = comedi_alloc_devpriv(dev, sizeof(*devpriv));
if (!devpriv)
return -ENOMEM;
/* set default amplitude and period */
if (amplitude <= 0)
amplitude = 1000000; /* 1 volt */
if (period <= 0)
period = 100000; /* 0.1 sec */
devpriv->uvolt_amplitude = amplitude;
devpriv->usec_period = period;
ret = comedi_alloc_subdevices(dev, 2);
if (ret)
return ret;
s = &dev->subdevices[0];
dev->read_subdev = s;
/* analog input subdevice */
s->type = COMEDI_SUBD_AI;
s->subdev_flags = SDF_READABLE | SDF_GROUND | SDF_CMD_READ;
s->n_chan = N_CHANS;
s->maxdata = 0xffff;
s->range_table = &waveform_ai_ranges;
s->len_chanlist = s->n_chan * 2;
s->insn_read = waveform_ai_insn_read;
s->do_cmd = waveform_ai_cmd;
s->do_cmdtest = waveform_ai_cmdtest;
s->cancel = waveform_ai_cancel;
s = &dev->subdevices[1];
dev->write_subdev = s;
/* analog output subdevice (loopback) */
s->type = COMEDI_SUBD_AO;
s->subdev_flags = SDF_WRITEABLE | SDF_GROUND;
s->n_chan = N_CHANS;
s->maxdata = 0xffff;
s->range_table = &waveform_ai_ranges;
s->insn_write = waveform_ao_insn_write;
/* Our default loopback value is just a 0V flatline */
for (i = 0; i < s->n_chan; i++)
devpriv->ao_loopbacks[i] = s->maxdata / 2;
init_timer(&devpriv->timer);
devpriv->timer.function = waveform_ai_interrupt;
devpriv->timer.data = (unsigned long)dev;
dev_info(dev->class_dev,
"%s: %i microvolt, %li microsecond waveform attached\n",
dev->board_name,
devpriv->uvolt_amplitude, devpriv->usec_period);
return 0;
}
static void waveform_detach(struct comedi_device *dev)
{
struct waveform_private *devpriv = dev->private;
if (devpriv)
waveform_ai_cancel(dev, dev->read_subdev);
}
static struct comedi_driver waveform_driver = {
.driver_name = "comedi_test",
.module = THIS_MODULE,
.attach = waveform_attach,
.detach = waveform_detach,
};
module_comedi_driver(waveform_driver);
MODULE_AUTHOR("Comedi http://www.comedi.org");
MODULE_DESCRIPTION("Comedi low-level driver");
MODULE_LICENSE("GPL");
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