drivers/staging/comedi/drivers/comedi_test.c

   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
  26 /*
  27  * Driver: comedi_test
  28  * Description: generates fake waveforms
  29  * Author: Joachim Wuttke <Joachim.Wuttke@icn.siemens.de>, Frank Mori Hess
  30  *   <fmhess@users.sourceforge.net>, ds
  31  * Devices:
  32  * Status: works
  33  * Updated: Sat, 16 Mar 2002 17:34:48 -0800
  34  *
  35  * This driver is mainly for testing purposes, but can also be used to
  36  * generate sample waveforms on systems that don't have data acquisition
  37  * hardware.
  38  *
  39  * Configuration options:
  40  *   [0] - Amplitude in microvolts for fake waveforms (default 1 volt)
  41  *   [1] - Period in microseconds for fake waveforms (default 0.1 sec)
  42  *
  43  * Generates a sawtooth wave on channel 0, square wave on channel 1, additional
  44  * waveforms could be added to other channels (currently they return flatline
  45  * zero volts).
  46  */
  47
  48 #include <linux/module.h>
  49 #include "../comedidev.h"
  50
  51 #include <asm/div64.h>
  52
  53 #include <linux/timer.h>
  54 #include <linux/ktime.h>
  55
  56 #define N_CHANS 8
  57
  58 enum waveform_state_bits {
  59         WAVEFORM_AI_RUNNING = 0
  60 };
  61
  62 /* Data unique to this driver */
  63 struct waveform_private {
  64         struct timer_list timer;
  65         u64 ai_last_scan_time;          /* time of last AI scan in usec */
  66         unsigned int uvolt_amplitude;   /* waveform amplitude in microvolts */
  67         unsigned int usec_period;       /* waveform period in microseconds */
  68         unsigned int usec_current;      /* current time (mod waveform period) */
  69         unsigned long state_bits;
  70         unsigned int scan_period;       /* scan period in usec */
  71         unsigned int convert_period;    /* conversion period in usec */
  72         unsigned int ao_loopbacks[N_CHANS];
  73 };
  74
  75 /* fake analog input ranges */
  76 static const struct comedi_lrange waveform_ai_ranges = {
  77         2, {
  78                 BIP_RANGE(10),
  79                 BIP_RANGE(5)
  80         }
  81 };
  82
  83 static unsigned short fake_sawtooth(struct comedi_device *dev,
  84                                     unsigned int range_index,
  85                                     unsigned int 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         value = current_time;
 100         value *= binary_amplitude * 2;
 101         do_div(value, devpriv->usec_period);
 102         value += offset;
 103         /* get rid of sawtooth's dc offset and clamp value */
 104         if (value < binary_amplitude) {
 105                 value = 0;                      /* negative saturation */
 106         } else {
 107                 value -= binary_amplitude;
 108                 if (value > s->maxdata)
 109                         value = s->maxdata;     /* positive saturation */
 110         }
 111
 112         return value;
 113 }
 114
 115 static unsigned short fake_squarewave(struct comedi_device *dev,
 116                                       unsigned int range_index,
 117                                       unsigned int current_time)
 118 {
 119         struct waveform_private *devpriv = dev->private;
 120         struct comedi_subdevice *s = dev->read_subdev;
 121         unsigned int offset = s->maxdata / 2;
 122         u64 value;
 123         const struct comedi_krange *krange =
 124             &s->range_table->range[range_index];
 125
 126         value = s->maxdata;
 127         value *= devpriv->uvolt_amplitude;
 128         do_div(value, krange->max - krange->min);
 129
 130         /* get one of two values for square-wave and clamp */
 131         if (current_time < devpriv->usec_period / 2) {
 132                 if (offset < value)
 133                         value = 0;              /* negative saturation */
 134                 else
 135                         value = offset - value;
 136         } else {
 137                 value += offset;
 138                 if (value > s->maxdata)
 139                         value = s->maxdata;     /* positive saturation */
 140         }
 141
 142         return value;
 143 }
 144
 145 static unsigned short fake_flatline(struct comedi_device *dev,
 146                                     unsigned int range_index,
 147                                     unsigned int current_time)
 148 {
 149         return dev->read_subdev->maxdata / 2;
 150 }
 151
 152 /* generates a different waveform depending on what channel is read */
 153 static unsigned short fake_waveform(struct comedi_device *dev,
 154                                     unsigned int channel, unsigned int range,
 155                                     unsigned int current_time)
 156 {
 157         enum {
 158                 SAWTOOTH_CHAN,
 159                 SQUARE_CHAN,
 160         };
 161         switch (channel) {
 162         case SAWTOOTH_CHAN:
 163                 return fake_sawtooth(dev, range, current_time);
 164         case SQUARE_CHAN:
 165                 return fake_squarewave(dev, range, current_time);
 166         default:
 167                 break;
 168         }
 169
 170         return fake_flatline(dev, range, current_time);
 171 }
 172
 173 /*
 174  * This is the background routine used to generate arbitrary data.
 175  * It should run in the background; therefore it is scheduled by
 176  * a timer mechanism.
 177  */
 178 static void waveform_ai_interrupt(unsigned long arg)
 179 {
 180         struct comedi_device *dev = (struct comedi_device *)arg;
 181         struct waveform_private *devpriv = dev->private;
 182         struct comedi_subdevice *s = dev->read_subdev;
 183         struct comedi_async *async = s->async;
 184         struct comedi_cmd *cmd = &async->cmd;
 185         unsigned int i, j;
 186         unsigned long elapsed_time;
 187         unsigned int num_scans;
 188
 189         /* check command is still active */
 190         if (!test_bit(WAVEFORM_AI_RUNNING, &devpriv->state_bits))
 191                 return;
 192
 193         elapsed_time = ktime_to_us(ktime_get()) - devpriv->ai_last_scan_time;
 194         num_scans = elapsed_time / devpriv->scan_period;
 195
 196         num_scans = comedi_nscans_left(s, num_scans);
 197         for (i = 0; i < num_scans; i++) {
 198                 unsigned int scan_remain_period = devpriv->scan_period;
 199
 200                 for (j = 0; j < cmd->chanlist_len; j++) {
 201                         unsigned short sample;
 202
 203                         if (devpriv->usec_current >= devpriv->usec_period)
 204                                 devpriv->usec_current %= devpriv->usec_period;
 205                         sample = fake_waveform(dev, CR_CHAN(cmd->chanlist[j]),
 206                                                CR_RANGE(cmd->chanlist[j]),
 207                                                devpriv->usec_current);
 208                         comedi_buf_write_samples(s, &sample, 1);
 209                         devpriv->usec_current += devpriv->convert_period;
 210                         scan_remain_period -= devpriv->convert_period;
 211                 }
 212                 devpriv->usec_current += scan_remain_period;
 213                 devpriv->ai_last_scan_time += devpriv->scan_period;
 214         }
 215         if (devpriv->usec_current >= devpriv->usec_period)
 216                 devpriv->usec_current %= devpriv->usec_period;
 217
 218         if (cmd->stop_src == TRIG_COUNT && async->scans_done >= cmd->stop_arg)
 219                 async->events |= COMEDI_CB_EOA;
 220         else
 221                 mod_timer(&devpriv->timer, jiffies + 1);
 222
 223         comedi_handle_events(dev, s);
 224 }
 225
 226 static int waveform_ai_cmdtest(struct comedi_device *dev,
 227                                struct comedi_subdevice *s,
 228                                struct comedi_cmd *cmd)
 229 {
 230         int err = 0;
 231         unsigned int arg, limit;
 232
 233         /* Step 1 : check if triggers are trivially valid */
 234
 235         err |= comedi_check_trigger_src(&cmd->start_src, TRIG_NOW);
 236         err |= comedi_check_trigger_src(&cmd->scan_begin_src,
 237                                         TRIG_FOLLOW | TRIG_TIMER);
 238         err |= comedi_check_trigger_src(&cmd->convert_src,
 239                                         TRIG_NOW | TRIG_TIMER);
 240         err |= comedi_check_trigger_src(&cmd->scan_end_src, TRIG_COUNT);
 241         err |= comedi_check_trigger_src(&cmd->stop_src, TRIG_COUNT | TRIG_NONE);
 242
 243         if (err)
 244                 return 1;
 245
 246         /* Step 2a : make sure trigger sources are unique */
 247
 248         err |= comedi_check_trigger_is_unique(cmd->convert_src);
 249         err |= comedi_check_trigger_is_unique(cmd->stop_src);
 250
 251         /* Step 2b : and mutually compatible */
 252
 253         if (cmd->scan_begin_src == TRIG_FOLLOW && cmd->convert_src == TRIG_NOW)
 254                 err |= -EINVAL;         /* scan period would be 0 */
 255
 256         if (err)
 257                 return 2;
 258
 259         /* Step 3: check if arguments are trivially valid */
 260
 261         err |= comedi_check_trigger_arg_is(&cmd->start_arg, 0);
 262
 263         if (cmd->convert_src == TRIG_NOW) {
 264                 err |= comedi_check_trigger_arg_is(&cmd->convert_arg, 0);
 265         } else {        /* cmd->convert_src == TRIG_TIMER */
 266                 if (cmd->scan_begin_src == TRIG_FOLLOW) {
 267                         err |= comedi_check_trigger_arg_min(&cmd->convert_arg,
 268                                                             NSEC_PER_USEC);
 269                 }
 270         }
 271
 272         if (cmd->scan_begin_src == TRIG_FOLLOW) {
 273                 err |= comedi_check_trigger_arg_is(&cmd->scan_begin_arg, 0);
 274         } else {        /* cmd->scan_begin_src == TRIG_TIMER */
 275                 err |= comedi_check_trigger_arg_min(&cmd->scan_begin_arg,
 276                                                     NSEC_PER_USEC);
 277         }
 278
 279         err |= comedi_check_trigger_arg_min(&cmd->chanlist_len, 1);
 280         err |= comedi_check_trigger_arg_is(&cmd->scan_end_arg,
 281                                            cmd->chanlist_len);
 282
 283         if (cmd->stop_src == TRIG_COUNT)
 284                 err |= comedi_check_trigger_arg_min(&cmd->stop_arg, 1);
 285         else    /* cmd->stop_src == TRIG_NONE */
 286                 err |= comedi_check_trigger_arg_is(&cmd->stop_arg, 0);
 287
 288         if (err)
 289                 return 3;
 290
 291         /* step 4: fix up any arguments */
 292
 293         if (cmd->convert_src == TRIG_TIMER) {
 294                 /* round convert_arg to nearest microsecond */
 295                 arg = cmd->convert_arg;
 296                 arg = min(arg,
 297                           rounddown(UINT_MAX, (unsigned int)NSEC_PER_USEC));
 298                 arg = NSEC_PER_USEC * DIV_ROUND_CLOSEST(arg, NSEC_PER_USEC);
 299                 if (cmd->scan_begin_arg == TRIG_TIMER) {
 300                         /* limit convert_arg to keep scan_begin_arg in range */
 301                         limit = UINT_MAX / cmd->scan_end_arg;
 302                         limit = rounddown(limit, (unsigned int)NSEC_PER_SEC);
 303                         arg = min(arg, limit);
 304                 }
 305                 err |= comedi_check_trigger_arg_is(&cmd->convert_arg, arg);
 306         }
 307
 308         if (cmd->scan_begin_src == TRIG_TIMER) {
 309                 /* round scan_begin_arg to nearest microsecond */
 310                 arg = cmd->scan_begin_arg;
 311                 arg = min(arg,
 312                           rounddown(UINT_MAX, (unsigned int)NSEC_PER_USEC));
 313                 arg = NSEC_PER_USEC * DIV_ROUND_CLOSEST(arg, NSEC_PER_USEC);
 314                 if (cmd->convert_src == TRIG_TIMER) {
 315                         /* but ensure scan_begin_arg is large enough */
 316                         arg = max(arg, cmd->convert_arg * cmd->scan_end_arg);
 317                 }
 318                 err |= comedi_check_trigger_arg_is(&cmd->scan_begin_arg, arg);
 319         }
 320
 321         if (err)
 322                 return 4;
 323
 324         return 0;
 325 }
 326
 327 static int waveform_ai_cmd(struct comedi_device *dev,
 328                            struct comedi_subdevice *s)
 329 {
 330         struct waveform_private *devpriv = dev->private;
 331         struct comedi_cmd *cmd = &s->async->cmd;
 332         u64 usec_current;
 333
 334         if (cmd->flags & CMDF_PRIORITY) {
 335                 dev_err(dev->class_dev,
 336                         "commands at RT priority not supported in this driver\n");
 337                 return -1;
 338         }
 339
 340         if (cmd->convert_src == TRIG_NOW)
 341                 devpriv->convert_period = 0;
 342         else            /* cmd->convert_src == TRIG_TIMER */
 343                 devpriv->convert_period = cmd->convert_arg / NSEC_PER_USEC;
 344
 345         if (cmd->scan_begin_src == TRIG_FOLLOW) {
 346                 devpriv->scan_period = devpriv->convert_period *
 347                                        cmd->scan_end_arg;
 348         } else {        /* cmd->scan_begin_src == TRIG_TIMER */
 349                 devpriv->scan_period = cmd->scan_begin_arg / NSEC_PER_USEC;
 350         }
 351
 352         devpriv->ai_last_scan_time = ktime_to_us(ktime_get());
 353         /* Determine time within waveform period. */
 354         usec_current = devpriv->ai_last_scan_time;
 355         devpriv->usec_current = do_div(usec_current, devpriv->usec_period);
 356
 357         devpriv->timer.expires = jiffies + 1;
 358         /* mark command as active */
 359         smp_mb__before_atomic();
 360         set_bit(WAVEFORM_AI_RUNNING, &devpriv->state_bits);
 361         smp_mb__after_atomic();
 362         add_timer(&devpriv->timer);
 363         return 0;
 364 }
 365
 366 static int waveform_ai_cancel(struct comedi_device *dev,
 367                               struct comedi_subdevice *s)
 368 {
 369         struct waveform_private *devpriv = dev->private;
 370
 371         /* mark command as no longer active */
 372         clear_bit(WAVEFORM_AI_RUNNING, &devpriv->state_bits);
 373         smp_mb__after_atomic();
 374         /* cannot call del_timer_sync() as may be called from timer routine */
 375         del_timer(&devpriv->timer);
 376         return 0;
 377 }
 378
 379 static int waveform_ai_insn_read(struct comedi_device *dev,
 380                                  struct comedi_subdevice *s,
 381                                  struct comedi_insn *insn, unsigned int *data)
 382 {
 383         struct waveform_private *devpriv = dev->private;
 384         int i, chan = CR_CHAN(insn->chanspec);
 385
 386         for (i = 0; i < insn->n; i++)
 387                 data[i] = devpriv->ao_loopbacks[chan];
 388
 389         return insn->n;
 390 }
 391
 392 static int waveform_ao_insn_write(struct comedi_device *dev,
 393                                   struct comedi_subdevice *s,
 394                                   struct comedi_insn *insn, unsigned int *data)
 395 {
 396         struct waveform_private *devpriv = dev->private;
 397         int i, chan = CR_CHAN(insn->chanspec);
 398
 399         for (i = 0; i < insn->n; i++)
 400                 devpriv->ao_loopbacks[chan] = data[i];
 401
 402         return insn->n;
 403 }
 404
 405 static int waveform_attach(struct comedi_device *dev,
 406                            struct comedi_devconfig *it)
 407 {
 408         struct waveform_private *devpriv;
 409         struct comedi_subdevice *s;
 410         int amplitude = it->options[0];
 411         int period = it->options[1];
 412         int i;
 413         int ret;
 414
 415         devpriv = comedi_alloc_devpriv(dev, sizeof(*devpriv));
 416         if (!devpriv)
 417                 return -ENOMEM;
 418
 419         /* set default amplitude and period */
 420         if (amplitude <= 0)
 421                 amplitude = 1000000;    /* 1 volt */
 422         if (period <= 0)
 423                 period = 100000;        /* 0.1 sec */
 424
 425         devpriv->uvolt_amplitude = amplitude;
 426         devpriv->usec_period = period;
 427
 428         ret = comedi_alloc_subdevices(dev, 2);
 429         if (ret)
 430                 return ret;
 431
 432         s = &dev->subdevices[0];
 433         dev->read_subdev = s;
 434         /* analog input subdevice */
 435         s->type = COMEDI_SUBD_AI;
 436         s->subdev_flags = SDF_READABLE | SDF_GROUND | SDF_CMD_READ;
 437         s->n_chan = N_CHANS;
 438         s->maxdata = 0xffff;
 439         s->range_table = &waveform_ai_ranges;
 440         s->len_chanlist = s->n_chan * 2;
 441         s->insn_read = waveform_ai_insn_read;
 442         s->do_cmd = waveform_ai_cmd;
 443         s->do_cmdtest = waveform_ai_cmdtest;
 444         s->cancel = waveform_ai_cancel;
 445
 446         s = &dev->subdevices[1];
 447         dev->write_subdev = s;
 448         /* analog output subdevice (loopback) */
 449         s->type = COMEDI_SUBD_AO;
 450         s->subdev_flags = SDF_WRITABLE | SDF_GROUND;
 451         s->n_chan = N_CHANS;
 452         s->maxdata = 0xffff;
 453         s->range_table = &waveform_ai_ranges;
 454         s->insn_write = waveform_ao_insn_write;
 455
 456         /* Our default loopback value is just a 0V flatline */
 457         for (i = 0; i < s->n_chan; i++)
 458                 devpriv->ao_loopbacks[i] = s->maxdata / 2;
 459
 460         setup_timer(&devpriv->timer, waveform_ai_interrupt,
 461                     (unsigned long)dev);
 462
 463         dev_info(dev->class_dev,
 464                  "%s: %u microvolt, %u microsecond waveform attached\n",
 465                  dev->board_name,
 466                  devpriv->uvolt_amplitude, devpriv->usec_period);
 467
 468         return 0;
 469 }
 470
 471 static void waveform_detach(struct comedi_device *dev)
 472 {
 473         struct waveform_private *devpriv = dev->private;
 474
 475         if (devpriv)
 476                 del_timer_sync(&devpriv->timer);
 477 }
 478
 479 static struct comedi_driver waveform_driver = {
 480         .driver_name    = "comedi_test",
 481         .module         = THIS_MODULE,
 482         .attach         = waveform_attach,
 483         .detach         = waveform_detach,
 484 };
 485 module_comedi_driver(waveform_driver);
 486
 487 MODULE_AUTHOR("Comedi http://www.comedi.org");
 488 MODULE_DESCRIPTION("Comedi low-level driver");
 489 MODULE_LICENSE("GPL");