--- /dev/null
+/*
+ dummy_waveform.c driver
+
+ 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.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, write to the Free Software
+ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+************************************************************************/
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/malloc.h>
+#include <linux/errno.h>
+#include <linux/delay.h>
+#include <linux/timer.h>
+#include <linux/time.h>
+#include <linux/init.h>
+#include <linux/comedidev.h>
+
+/* Board descriptions */
+typedef struct waveform_board_struct{
+ char *name;
+ int ai_chans;
+ int ai_bits;
+ int have_dio;
+} waveform_board;
+static waveform_board waveform_boards[] = {
+ {
+ name: "dummy_waveform",
+ ai_chans: 8,
+ ai_bits: 16,
+ have_dio: 0,
+ },
+};
+#define thisboard ((waveform_board *)dev->board_ptr)
+
+/* Data unique to this driver */
+typedef struct{
+ struct timer_list timer;
+ struct timeval last; // time at which last timer interrupt occured
+ unsigned int uvolt_amplitude; // waveform amplitude in microvolts
+ unsigned long usec_period; // waveform period in microseconds
+ unsigned long usec_current; // current time (modulo waveform period)
+ volatile unsigned long ai_count; // number of conversions remaining
+ volatile unsigned timer_running : 1;
+} waveform_private;
+#define devpriv ((waveform_private *)dev->private)
+
+static int waveform_attach(comedi_device *dev,comedi_devconfig *it);
+static int waveform_detach(comedi_device *dev);
+static comedi_driver driver_waveform={
+ driver_name: "dummy_waveform",
+ module: THIS_MODULE,
+ attach: waveform_attach,
+ detach: waveform_detach,
+ board_name: waveform_boards,
+ offset: sizeof(waveform_board),
+ num_names: sizeof(waveform_boards) / sizeof(waveform_board),
+};
+
+static int waveform_ai_cmdtest(comedi_device *dev,comedi_subdevice *s,
+ comedi_cmd *cmd);
+static int waveform_ai_cmd(comedi_device *dev, comedi_subdevice *s);
+static int waveform_ai_cancel(comedi_device *dev, comedi_subdevice *s);
+static int waveform_ai_insn_read(comedi_device *dev, comedi_subdevice *s, comedi_insn *insn, lsampl_t *data);
+static sampl_t fake_sawtooth(comedi_device *dev, unsigned long 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.
+*/
+void waveform_ai_interrupt(unsigned long arg)
+{
+ comedi_device *dev = (comedi_device*) arg;
+ comedi_async *async = dev->read_subdev->async;
+ comedi_cmd *cmd = &async->cmd;
+ unsigned long i;
+ // all times in microsec
+ unsigned long elapsed_time;
+ unsigned int num_scans;
+ unsigned int scan_period = async->cmd.scan_begin_arg / 1000;
+ unsigned int remainder = devpriv->usec_current % scan_period;
+ struct timeval now;
+
+ 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 = (remainder + elapsed_time) / scan_period;
+
+ async->events = 0;
+
+ for(i = 0; i < num_scans; i++)
+ {
+ comedi_buf_put(async,
+ fake_sawtooth(dev, devpriv->usec_current + i * scan_period));
+ devpriv->ai_count++;
+ if(cmd->stop_src == TRIG_COUNT && devpriv->ai_count >= cmd->stop_arg)
+ {
+ async->events |= COMEDI_CB_EOA;
+ break;
+ }
+ }
+
+ devpriv->usec_current += elapsed_time;
+ devpriv->usec_current %= devpriv->usec_period;
+
+ async->events |= COMEDI_CB_BLOCK;
+
+ if((async->events & COMEDI_CB_EOA) == 0 && devpriv->timer_running)
+ mod_timer(&devpriv->timer, jiffies + 1);
+
+ comedi_event(dev, dev->read_subdev, async->events);
+}
+
+static int waveform_attach(comedi_device *dev,comedi_devconfig *it)
+{
+ comedi_subdevice *s;
+ int amplitude = it->options[0];
+ int period = it->options[1];
+
+ printk("comedi%d: dummy_waveform: ", dev->minor);
+
+ dev->board_name = thisboard->name;
+
+ if(alloc_private(dev, sizeof(waveform_private)) < 0)
+ 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;
+
+ printk("%i microvolt, %li microsecond waveform ", devpriv->uvolt_amplitude, devpriv->usec_period);
+ dev->n_subdevices = 1;
+ if(alloc_subdevices(dev) < 0) return -ENOMEM;
+
+ s = dev->subdevices + 0;
+ dev->read_subdev = s;
+ /* analog input subdevice */
+ s->type = COMEDI_SUBD_AI;
+ s->subdev_flags = SDF_READABLE | SDF_GROUND;
+ s->n_chan = thisboard->ai_chans;
+ s->maxdata = (1 << thisboard->ai_bits) - 1;
+ s->range_table = &range_bipolar10;
+ s->len_chanlist = 16;
+ s->insn_read = waveform_ai_insn_read; // apparently, we do not need waveform_ai_rinsn;
+ s->do_cmd = waveform_ai_cmd;
+ s->do_cmdtest = waveform_ai_cmdtest;
+ s->cancel = waveform_ai_cancel;
+
+ init_timer(&(devpriv->timer));
+ devpriv->timer.function = waveform_ai_interrupt;
+ devpriv->timer.data = (unsigned long) dev;
+
+ printk("attached\n");
+
+ return 1;
+}
+
+static int waveform_detach(comedi_device *dev)
+{
+ printk("comedi%d: dummy_waveform: remove\n",dev->minor);
+
+ if(dev->private)
+ {
+ waveform_ai_cancel(dev, dev->read_subdev);
+ }
+
+ return 0;
+}
+
+static int waveform_ai_cmdtest(comedi_device *dev,comedi_subdevice *s,
+ comedi_cmd *cmd)
+{
+ int err = 0;
+ int tmp;
+
+ /* step 1: make sure trigger sources are trivially valid */
+
+ tmp = cmd->start_src;
+ cmd->start_src &= TRIG_NOW;
+ if(!cmd->start_src || tmp != cmd->start_src) err++;
+
+ tmp = cmd->scan_begin_src;
+ cmd->scan_begin_src &= TRIG_TIMER;
+ if(!cmd->scan_begin_src || tmp != cmd->scan_begin_src) err++;
+
+ tmp = cmd->convert_src;
+ cmd->convert_src &= TRIG_NOW;
+ if(!cmd->convert_src || tmp != cmd->convert_src) err++;
+
+ tmp = cmd->scan_end_src;
+ cmd->scan_end_src &= TRIG_COUNT;
+ if(!cmd->scan_end_src || tmp != cmd->scan_end_src) err++;
+
+ tmp=cmd->stop_src;
+ cmd->stop_src &= TRIG_COUNT | TRIG_NONE;
+ if(!cmd->stop_src || tmp!=cmd->stop_src) err++;
+
+ if(err) return 1;
+
+ /* step 2: make sure trigger sources are unique and mutually compatible */
+
+ if(cmd->stop_src != TRIG_COUNT &&
+ cmd->stop_src != TRIG_NONE) err++;
+
+ if(err)return 2;
+
+ /* step 3: make sure arguments are trivially compatible */
+
+ if(cmd->start_arg != 0)
+ {
+ cmd->start_arg = 0;
+ err++;
+ }
+ if(cmd->convert_arg != 0)
+ {
+ cmd->convert_arg = 0;
+ err++;
+ }
+ if(cmd->scan_begin_src == TRIG_TIMER)
+ {
+ if(cmd->scan_begin_arg < 1000)
+ cmd->scan_begin_arg = 1000;
+ }
+
+ // XXX these checks are generic and should go in core if not there already
+ if(!cmd->chanlist_len)
+ {
+ cmd->chanlist_len = 1;
+ err++;
+ }
+ if(cmd->scan_end_arg != cmd->chanlist_len)
+ {
+ cmd->scan_end_arg = cmd->chanlist_len;
+ err++;
+ }
+
+ if(cmd->stop_src == TRIG_COUNT)
+ {
+ if(!cmd->stop_arg)
+ {
+ cmd->stop_arg = 1;
+ err++;
+ }
+ } else
+ { /* TRIG_NONE */
+ if(cmd->stop_arg != 0)
+ {
+ cmd->stop_arg = 0;
+ err++;
+ }
+ }
+
+ if(err)return 3;
+
+ /* step 4: fix up any arguments */
+
+ if(cmd->scan_begin_src == TRIG_TIMER)
+ {
+ const int nano_per_micro = 1000;
+ tmp = cmd->scan_begin_arg;
+ // round to nearest microsec
+ cmd->scan_begin_arg = nano_per_micro * ((tmp + (nano_per_micro / 2)) / nano_per_micro);
+ if(tmp != cmd->scan_begin_arg) err++;
+ }
+
+ if(err) return 4;
+
+ return 0;
+}
+
+static int waveform_ai_cmd(comedi_device *dev, comedi_subdevice *s)
+{
+ comedi_cmd *cmd = &s->async->cmd;
+
+ devpriv->timer_running = 1;
+
+ if(cmd->stop_src == TRIG_COUNT)
+ devpriv->ai_count = 0;
+
+ do_gettimeofday(&devpriv->last);
+ devpriv->usec_current = 0;
+
+ devpriv->timer.expires = jiffies + 1;
+ add_timer(&devpriv->timer);
+ return 0;
+}
+
+static int waveform_ai_cancel(comedi_device *dev, comedi_subdevice *s)
+{
+ devpriv->timer_running = 0;
+ del_timer(&devpriv->timer);
+ return 0;
+}
+
+// divides an unsigned long long
+unsigned long long my_ull_div(unsigned long long numerator, unsigned long denominator)
+{
+ u32 value;
+ unsigned long long remainder;
+ unsigned int shift = 0;
+ const unsigned long max_u32 = 0xffffffff;
+
+ if(numerator <= max_u32)
+ {
+ // numerator is small enough that we can return correct result
+ value = numerator;
+ return value / denominator;
+ }
+
+ remainder = numerator;
+
+ // otherwise shift most significant bits into 32 bit variable
+ while(numerator > max_u32)
+ {
+ numerator >>= 1;
+ shift++;
+ }
+ value = numerator;
+ value /= denominator;
+ value <<= shift;
+
+ remainder -= ((unsigned long long) value) * denominator;
+
+ return value + my_ull_div(remainder, denominator);
+}
+
+static sampl_t fake_sawtooth(comedi_device *dev, unsigned long current_time)
+{
+ comedi_subdevice *s = dev->read_subdev;
+ unsigned int offset = s->maxdata / 2;
+ unsigned long long value = 0;
+
+ current_time %= devpriv->usec_period;
+ value = current_time;
+ value *= s->maxdata;
+ value = my_ull_div(value, devpriv->usec_period);
+ value *= devpriv->uvolt_amplitude;
+ value = my_ull_div(value, 20000000); // XXX
+
+ return offset + value;
+}
+
+static int waveform_ai_insn_read(comedi_device *dev, comedi_subdevice *s, comedi_insn *insn, lsampl_t *data)
+{
+ int i;
+ for(i = 0; i < insn->n; i++)
+ data[i] = i;
+
+ return insn->n;
+}
+
+COMEDI_INITCLEANUP(driver_waveform);
+
projects / comedi.git / commitdiff