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 #include <linux/jiffies.h>
  56
  57 #define N_CHANS 8
  58
  59 enum waveform_state_bits {
  60         WAVEFORM_AI_RUNNING,
  61         WAVEFORM_AO_RUNNING
  62 };
  63
  64 /* Data unique to this driver */
  65 struct waveform_private {
  66         struct timer_list ai_timer;     /* timer for AI commands */
  67         u64 ai_convert_time;            /* time of next AI conversion in usec */
  68         unsigned int wf_amplitude;      /* waveform amplitude in microvolts */
  69         unsigned int wf_period;         /* waveform period in microseconds */
  70         unsigned int wf_current;        /* current time in waveform period */
  71         unsigned long state_bits;
  72         unsigned int ai_scan_period;    /* AI scan period in usec */
  73         unsigned int ai_convert_period; /* AI conversion period in usec */
  74         struct timer_list ao_timer;     /* timer for AO commands */
  75         u64 ao_last_scan_time;          /* time of previous AO scan in usec */
  76         unsigned int ao_scan_period;    /* AO scan period in usec */
  77         unsigned short ao_loopbacks[N_CHANS];
  78 };
  79
  80 /* fake analog input ranges */
  81 static const struct comedi_lrange waveform_ai_ranges = {
  82         2, {
  83                 BIP_RANGE(10),
  84                 BIP_RANGE(5)
  85         }
  86 };
  87
  88 static unsigned short fake_sawtooth(struct comedi_device *dev,
  89                                     unsigned int range_index,
  90                                     unsigned int current_time)
  91 {
  92         struct waveform_private *devpriv = dev->private;
  93         struct comedi_subdevice *s = dev->read_subdev;
  94         unsigned int offset = s->maxdata / 2;
  95         u64 value;
  96         const struct comedi_krange *krange =
  97             &s->range_table->range[range_index];
  98         u64 binary_amplitude;
  99
 100         binary_amplitude = s->maxdata;
 101         binary_amplitude *= devpriv->wf_amplitude;
 102         do_div(binary_amplitude, krange->max - krange->min);
 103
 104         value = current_time;
 105         value *= binary_amplitude * 2;
 106         do_div(value, devpriv->wf_period);
 107         value += offset;
 108         /* get rid of sawtooth's dc offset and clamp value */
 109         if (value < binary_amplitude) {
 110                 value = 0;                      /* negative saturation */
 111         } else {
 112                 value -= binary_amplitude;
 113                 if (value > s->maxdata)
 114                         value = s->maxdata;     /* positive saturation */
 115         }
 116
 117         return value;
 118 }
 119
 120 static unsigned short fake_squarewave(struct comedi_device *dev,
 121                                       unsigned int range_index,
 122                                       unsigned int current_time)
 123 {
 124         struct waveform_private *devpriv = dev->private;
 125         struct comedi_subdevice *s = dev->read_subdev;
 126         unsigned int offset = s->maxdata / 2;
 127         u64 value;
 128         const struct comedi_krange *krange =
 129             &s->range_table->range[range_index];
 130
 131         value = s->maxdata;
 132         value *= devpriv->wf_amplitude;
 133         do_div(value, krange->max - krange->min);
 134
 135         /* get one of two values for square-wave and clamp */
 136         if (current_time < devpriv->wf_period / 2) {
 137                 if (offset < value)
 138                         value = 0;              /* negative saturation */
 139                 else
 140                         value = offset - value;
 141         } else {
 142                 value += offset;
 143                 if (value > s->maxdata)
 144                         value = s->maxdata;     /* positive saturation */
 145         }
 146
 147         return value;
 148 }
 149
 150 static unsigned short fake_flatline(struct comedi_device *dev,
 151                                     unsigned int range_index,
 152                                     unsigned int current_time)
 153 {
 154         return dev->read_subdev->maxdata / 2;
 155 }
 156
 157 /* generates a different waveform depending on what channel is read */
 158 static unsigned short fake_waveform(struct comedi_device *dev,
 159                                     unsigned int channel, unsigned int range,
 160                                     unsigned int current_time)
 161 {
 162         enum {
 163                 SAWTOOTH_CHAN,
 164                 SQUARE_CHAN,
 165         };
 166         switch (channel) {
 167         case SAWTOOTH_CHAN:
 168                 return fake_sawtooth(dev, range, current_time);
 169         case SQUARE_CHAN:
 170                 return fake_squarewave(dev, range, current_time);
 171         default:
 172                 break;
 173         }
 174
 175         return fake_flatline(dev, range, current_time);
 176 }
 177
 178 /*
 179  * This is the background routine used to generate arbitrary data.
 180  * It should run in the background; therefore it is scheduled by
 181  * a timer mechanism.
 182  */
 183 static void waveform_ai_timer(unsigned long arg)
 184 {
 185         struct comedi_device *dev = (struct comedi_device *)arg;
 186         struct waveform_private *devpriv = dev->private;
 187         struct comedi_subdevice *s = dev->read_subdev;
 188         struct comedi_async *async = s->async;
 189         struct comedi_cmd *cmd = &async->cmd;
 190         u64 now;
 191         unsigned int nsamples;
 192         unsigned int time_increment;
 193
 194         /* check command is still active */
 195         if (!test_bit(WAVEFORM_AI_RUNNING, &devpriv->state_bits))
 196                 return;
 197
 198         now = ktime_to_us(ktime_get());
 199         nsamples = comedi_nsamples_left(s, UINT_MAX);
 200
 201         while (nsamples && devpriv->ai_convert_time < now) {
 202                 unsigned int chanspec = cmd->chanlist[async->cur_chan];
 203                 unsigned short sample;
 204
 205                 sample = fake_waveform(dev, CR_CHAN(chanspec),
 206                                        CR_RANGE(chanspec), devpriv->wf_current);
 207                 if (comedi_buf_write_samples(s, &sample, 1) == 0)
 208                         goto overrun;
 209                 time_increment = devpriv->ai_convert_period;
 210                 if (async->scan_progress == 0) {
 211                         /* done last conversion in scan, so add dead time */
 212                         time_increment += devpriv->ai_scan_period -
 213                                           devpriv->ai_convert_period *
 214                                           cmd->scan_end_arg;
 215                 }
 216                 devpriv->wf_current += time_increment;
 217                 if (devpriv->wf_current >= devpriv->wf_period)
 218                         devpriv->wf_current %= devpriv->wf_period;
 219                 devpriv->ai_convert_time += time_increment;
 220                 nsamples--;
 221         }
 222
 223         if (cmd->stop_src == TRIG_COUNT && async->scans_done >= cmd->stop_arg) {
 224                 async->events |= COMEDI_CB_EOA;
 225         } else {
 226                 if (devpriv->ai_convert_time > now)
 227                         time_increment = devpriv->ai_convert_time - now;
 228                 else
 229                         time_increment = 1;
 230                 mod_timer(&devpriv->ai_timer,
 231                           jiffies + usecs_to_jiffies(time_increment));
 232         }
 233
 234 overrun:
 235         comedi_handle_events(dev, s);
 236 }
 237
 238 static int waveform_ai_cmdtest(struct comedi_device *dev,
 239                                struct comedi_subdevice *s,
 240                                struct comedi_cmd *cmd)
 241 {
 242         int err = 0;
 243         unsigned int arg, limit;
 244
 245         /* Step 1 : check if triggers are trivially valid */
 246
 247         err |= comedi_check_trigger_src(&cmd->start_src, TRIG_NOW);
 248         err |= comedi_check_trigger_src(&cmd->scan_begin_src,
 249                                         TRIG_FOLLOW | TRIG_TIMER);
 250         err |= comedi_check_trigger_src(&cmd->convert_src,
 251                                         TRIG_NOW | TRIG_TIMER);
 252         err |= comedi_check_trigger_src(&cmd->scan_end_src, TRIG_COUNT);
 253         err |= comedi_check_trigger_src(&cmd->stop_src, TRIG_COUNT | TRIG_NONE);
 254
 255         if (err)
 256                 return 1;
 257
 258         /* Step 2a : make sure trigger sources are unique */
 259
 260         err |= comedi_check_trigger_is_unique(cmd->convert_src);
 261         err |= comedi_check_trigger_is_unique(cmd->stop_src);
 262
 263         /* Step 2b : and mutually compatible */
 264
 265         if (cmd->scan_begin_src == TRIG_FOLLOW && cmd->convert_src == TRIG_NOW)
 266                 err |= -EINVAL;         /* scan period would be 0 */
 267
 268         if (err)
 269                 return 2;
 270
 271         /* Step 3: check if arguments are trivially valid */
 272
 273         err |= comedi_check_trigger_arg_is(&cmd->start_arg, 0);
 274
 275         if (cmd->convert_src == TRIG_NOW) {
 276                 err |= comedi_check_trigger_arg_is(&cmd->convert_arg, 0);
 277         } else {        /* cmd->convert_src == TRIG_TIMER */
 278                 if (cmd->scan_begin_src == TRIG_FOLLOW) {
 279                         err |= comedi_check_trigger_arg_min(&cmd->convert_arg,
 280                                                             NSEC_PER_USEC);
 281                 }
 282         }
 283
 284         if (cmd->scan_begin_src == TRIG_FOLLOW) {
 285                 err |= comedi_check_trigger_arg_is(&cmd->scan_begin_arg, 0);
 286         } else {        /* cmd->scan_begin_src == TRIG_TIMER */
 287                 err |= comedi_check_trigger_arg_min(&cmd->scan_begin_arg,
 288                                                     NSEC_PER_USEC);
 289         }
 290
 291         err |= comedi_check_trigger_arg_min(&cmd->chanlist_len, 1);
 292         err |= comedi_check_trigger_arg_is(&cmd->scan_end_arg,
 293                                            cmd->chanlist_len);
 294
 295         if (cmd->stop_src == TRIG_COUNT)
 296                 err |= comedi_check_trigger_arg_min(&cmd->stop_arg, 1);
 297         else    /* cmd->stop_src == TRIG_NONE */
 298                 err |= comedi_check_trigger_arg_is(&cmd->stop_arg, 0);
 299
 300         if (err)
 301                 return 3;
 302
 303         /* step 4: fix up any arguments */
 304
 305         if (cmd->convert_src == TRIG_TIMER) {
 306                 /* round convert_arg to nearest microsecond */
 307                 arg = cmd->convert_arg;
 308                 arg = min(arg,
 309                           rounddown(UINT_MAX, (unsigned int)NSEC_PER_USEC));
 310                 arg = NSEC_PER_USEC * DIV_ROUND_CLOSEST(arg, NSEC_PER_USEC);
 311                 if (cmd->scan_begin_arg == TRIG_TIMER) {
 312                         /* limit convert_arg to keep scan_begin_arg in range */
 313                         limit = UINT_MAX / cmd->scan_end_arg;
 314                         limit = rounddown(limit, (unsigned int)NSEC_PER_SEC);
 315                         arg = min(arg, limit);
 316                 }
 317                 err |= comedi_check_trigger_arg_is(&cmd->convert_arg, arg);
 318         }
 319
 320         if (cmd->scan_begin_src == TRIG_TIMER) {
 321                 /* round scan_begin_arg to nearest microsecond */
 322                 arg = cmd->scan_begin_arg;
 323                 arg = min(arg,
 324                           rounddown(UINT_MAX, (unsigned int)NSEC_PER_USEC));
 325                 arg = NSEC_PER_USEC * DIV_ROUND_CLOSEST(arg, NSEC_PER_USEC);
 326                 if (cmd->convert_src == TRIG_TIMER) {
 327                         /* but ensure scan_begin_arg is large enough */
 328                         arg = max(arg, cmd->convert_arg * cmd->scan_end_arg);
 329                 }
 330                 err |= comedi_check_trigger_arg_is(&cmd->scan_begin_arg, arg);
 331         }
 332
 333         if (err)
 334                 return 4;
 335
 336         return 0;
 337 }
 338
 339 static int waveform_ai_cmd(struct comedi_device *dev,
 340                            struct comedi_subdevice *s)
 341 {
 342         struct waveform_private *devpriv = dev->private;
 343         struct comedi_cmd *cmd = &s->async->cmd;
 344         unsigned int first_convert_time;
 345         u64 wf_current;
 346
 347         if (cmd->flags & CMDF_PRIORITY) {
 348                 dev_err(dev->class_dev,
 349                         "commands at RT priority not supported in this driver\n");
 350                 return -1;
 351         }
 352
 353         if (cmd->convert_src == TRIG_NOW)
 354                 devpriv->ai_convert_period = 0;
 355         else            /* cmd->convert_src == TRIG_TIMER */
 356                 devpriv->ai_convert_period = cmd->convert_arg / NSEC_PER_USEC;
 357
 358         if (cmd->scan_begin_src == TRIG_FOLLOW) {
 359                 devpriv->ai_scan_period = devpriv->ai_convert_period *
 360                                           cmd->scan_end_arg;
 361         } else {        /* cmd->scan_begin_src == TRIG_TIMER */
 362                 devpriv->ai_scan_period = cmd->scan_begin_arg / NSEC_PER_USEC;
 363         }
 364
 365         /*
 366          * Simulate first conversion to occur at convert period after
 367          * conversion timer starts.  If scan_begin_src is TRIG_FOLLOW, assume
 368          * the conversion timer starts immediately.  If scan_begin_src is
 369          * TRIG_TIMER, assume the conversion timer starts after the scan
 370          * period.
 371          */
 372         first_convert_time = devpriv->ai_convert_period;
 373         if (cmd->scan_begin_src == TRIG_TIMER)
 374                 first_convert_time += devpriv->ai_scan_period;
 375         devpriv->ai_convert_time = ktime_to_us(ktime_get()) +
 376                                    first_convert_time;
 377
 378         /* Determine time within waveform period at time of conversion. */
 379         wf_current = devpriv->ai_convert_time;
 380         devpriv->wf_current = do_div(wf_current, devpriv->wf_period);
 381
 382         /*
 383          * Schedule timer to expire just after first conversion time.
 384          * Seem to need an extra jiffy here, otherwise timer expires slightly
 385          * early!
 386          */
 387         devpriv->ai_timer.expires =
 388                 jiffies + usecs_to_jiffies(devpriv->ai_convert_period) + 1;
 389
 390         /* mark command as active */
 391         smp_mb__before_atomic();
 392         set_bit(WAVEFORM_AI_RUNNING, &devpriv->state_bits);
 393         smp_mb__after_atomic();
 394         add_timer(&devpriv->ai_timer);
 395         return 0;
 396 }
 397
 398 static int waveform_ai_cancel(struct comedi_device *dev,
 399                               struct comedi_subdevice *s)
 400 {
 401         struct waveform_private *devpriv = dev->private;
 402
 403         /* mark command as no longer active */
 404         clear_bit(WAVEFORM_AI_RUNNING, &devpriv->state_bits);
 405         smp_mb__after_atomic();
 406         /* cannot call del_timer_sync() as may be called from timer routine */
 407         del_timer(&devpriv->ai_timer);
 408         return 0;
 409 }
 410
 411 static int waveform_ai_insn_read(struct comedi_device *dev,
 412                                  struct comedi_subdevice *s,
 413                                  struct comedi_insn *insn, unsigned int *data)
 414 {
 415         struct waveform_private *devpriv = dev->private;
 416         int i, chan = CR_CHAN(insn->chanspec);
 417
 418         for (i = 0; i < insn->n; i++)
 419                 data[i] = devpriv->ao_loopbacks[chan];
 420
 421         return insn->n;
 422 }
 423
 424 /*
 425  * This is the background routine to handle AO commands, scheduled by
 426  * a timer mechanism.
 427  */
 428 static void waveform_ao_timer(unsigned long arg)
 429 {
 430         struct comedi_device *dev = (struct comedi_device *)arg;
 431         struct waveform_private *devpriv = dev->private;
 432         struct comedi_subdevice *s = dev->write_subdev;
 433         struct comedi_async *async = s->async;
 434         struct comedi_cmd *cmd = &async->cmd;
 435         u64 now;
 436         u64 scans_since;
 437         unsigned int scans_avail = 0;
 438
 439         /* check command is still active */
 440         if (!test_bit(WAVEFORM_AO_RUNNING, &devpriv->state_bits))
 441                 return;
 442
 443         /* determine number of scan periods since last time */
 444         now = ktime_to_us(ktime_get());
 445         scans_since = now - devpriv->ao_last_scan_time;
 446         do_div(scans_since, devpriv->ao_scan_period);
 447         if (scans_since) {
 448                 unsigned int i;
 449
 450                 /* determine scans in buffer, limit to scans to do this time */
 451                 scans_avail = comedi_nscans_left(s, 0);
 452                 if (scans_avail > scans_since)
 453                         scans_avail = scans_since;
 454                 if (scans_avail) {
 455                         /* skip all but the last scan to save processing time */
 456                         if (scans_avail > 1) {
 457                                 unsigned int skip_bytes, nbytes;
 458
 459                                 skip_bytes =
 460                                 comedi_samples_to_bytes(s, cmd->scan_end_arg *
 461                                                            (scans_avail - 1));
 462                                 nbytes = comedi_buf_read_alloc(s, skip_bytes);
 463                                 comedi_buf_read_free(s, nbytes);
 464                                 comedi_inc_scan_progress(s, nbytes);
 465                                 if (nbytes < skip_bytes) {
 466                                         /* unexpected underrun! (cancelled?) */
 467                                         async->events |= COMEDI_CB_OVERFLOW;
 468                                         goto underrun;
 469                                 }
 470                         }
 471                         /* output the last scan */
 472                         for (i = 0; i < cmd->scan_end_arg; i++) {
 473                                 unsigned int chan = CR_CHAN(cmd->chanlist[i]);
 474
 475                                 if (comedi_buf_read_samples(s,
 476                                                             &devpriv->
 477                                                              ao_loopbacks[chan],
 478                                                             1) == 0) {
 479                                         /* unexpected underrun! (cancelled?) */
 480                                         async->events |= COMEDI_CB_OVERFLOW;
 481                                         goto underrun;
 482                                 }
 483                         }
 484                         /* advance time of last scan */
 485                         devpriv->ao_last_scan_time +=
 486                                 (u64)scans_avail * devpriv->ao_scan_period;
 487                 }
 488         }
 489         if (cmd->stop_src == TRIG_COUNT && async->scans_done >= cmd->stop_arg) {
 490                 async->events |= COMEDI_CB_EOA;
 491         } else if (scans_avail < scans_since) {
 492                 async->events |= COMEDI_CB_OVERFLOW;
 493         } else {
 494                 unsigned int time_inc = devpriv->ao_last_scan_time +
 495                                         devpriv->ao_scan_period - now;
 496
 497                 mod_timer(&devpriv->ao_timer,
 498                           jiffies + usecs_to_jiffies(time_inc));
 499         }
 500
 501 underrun:
 502         comedi_handle_events(dev, s);
 503 }
 504
 505 static int waveform_ao_inttrig_start(struct comedi_device *dev,
 506                                      struct comedi_subdevice *s,
 507                                      unsigned int trig_num)
 508 {
 509         struct waveform_private *devpriv = dev->private;
 510         struct comedi_async *async = s->async;
 511         struct comedi_cmd *cmd = &async->cmd;
 512
 513         if (trig_num != cmd->start_arg)
 514                 return -EINVAL;
 515
 516         async->inttrig = NULL;
 517
 518         devpriv->ao_last_scan_time = ktime_to_us(ktime_get());
 519         devpriv->ao_timer.expires =
 520                 jiffies + usecs_to_jiffies(devpriv->ao_scan_period);
 521
 522         /* mark command as active */
 523         smp_mb__before_atomic();
 524         set_bit(WAVEFORM_AO_RUNNING, &devpriv->state_bits);
 525         smp_mb__after_atomic();
 526         add_timer(&devpriv->ao_timer);
 527
 528         return 1;
 529 }
 530
 531 static int waveform_ao_cmdtest(struct comedi_device *dev,
 532                                struct comedi_subdevice *s,
 533                                struct comedi_cmd *cmd)
 534 {
 535         int err = 0;
 536         unsigned int arg;
 537
 538         /* Step 1 : check if triggers are trivially valid */
 539
 540         err |= comedi_check_trigger_src(&cmd->start_src, TRIG_INT);
 541         err |= comedi_check_trigger_src(&cmd->scan_begin_src, TRIG_TIMER);
 542         err |= comedi_check_trigger_src(&cmd->convert_src, TRIG_NOW);
 543         err |= comedi_check_trigger_src(&cmd->scan_end_src, TRIG_COUNT);
 544         err |= comedi_check_trigger_src(&cmd->stop_src, TRIG_COUNT | TRIG_NONE);
 545
 546         if (err)
 547                 return 1;
 548
 549         /* Step 2a : make sure trigger sources are unique */
 550
 551         err |= comedi_check_trigger_is_unique(cmd->stop_src);
 552
 553         /* Step 2b : and mutually compatible */
 554
 555         if (err)
 556                 return 2;
 557
 558         /* Step 3: check if arguments are trivially valid */
 559
 560         err |= comedi_check_trigger_arg_min(&cmd->scan_begin_arg,
 561                                             NSEC_PER_USEC);
 562         err |= comedi_check_trigger_arg_is(&cmd->convert_arg, 0);
 563         err |= comedi_check_trigger_arg_min(&cmd->chanlist_len, 1);
 564         err |= comedi_check_trigger_arg_is(&cmd->scan_end_arg,
 565                                            cmd->chanlist_len);
 566         if (cmd->stop_src == TRIG_COUNT)
 567                 err |= comedi_check_trigger_arg_min(&cmd->stop_arg, 1);
 568         else    /* cmd->stop_src == TRIG_NONE */
 569                 err |= comedi_check_trigger_arg_is(&cmd->stop_arg, 0);
 570
 571         if (err)
 572                 return 3;
 573
 574         /* step 4: fix up any arguments */
 575
 576         /* round scan_begin_arg to nearest microsecond */
 577         arg = cmd->scan_begin_arg;
 578         arg = min(arg, rounddown(UINT_MAX, (unsigned int)NSEC_PER_USEC));
 579         arg = NSEC_PER_USEC * DIV_ROUND_CLOSEST(arg, NSEC_PER_USEC);
 580         err |= comedi_check_trigger_arg_is(&cmd->scan_begin_arg, arg);
 581
 582         if (err)
 583                 return 4;
 584
 585         return 0;
 586 }
 587
 588 static int waveform_ao_cmd(struct comedi_device *dev,
 589                            struct comedi_subdevice *s)
 590 {
 591         struct waveform_private *devpriv = dev->private;
 592         struct comedi_cmd *cmd = &s->async->cmd;
 593
 594         if (cmd->flags & CMDF_PRIORITY) {
 595                 dev_err(dev->class_dev,
 596                         "commands at RT priority not supported in this driver\n");
 597                 return -1;
 598         }
 599
 600         devpriv->ao_scan_period = cmd->scan_begin_arg / NSEC_PER_USEC;
 601         s->async->inttrig = waveform_ao_inttrig_start;
 602         return 0;
 603 }
 604
 605 static int waveform_ao_cancel(struct comedi_device *dev,
 606                               struct comedi_subdevice *s)
 607 {
 608         struct waveform_private *devpriv = dev->private;
 609
 610         s->async->inttrig = NULL;
 611         /* mark command as no longer active */
 612         clear_bit(WAVEFORM_AO_RUNNING, &devpriv->state_bits);
 613         smp_mb__after_atomic();
 614         /* cannot call del_timer_sync() as may be called from timer routine */
 615         del_timer(&devpriv->ao_timer);
 616         return 0;
 617 }
 618
 619 static int waveform_ao_insn_write(struct comedi_device *dev,
 620                                   struct comedi_subdevice *s,
 621                                   struct comedi_insn *insn, unsigned int *data)
 622 {
 623         struct waveform_private *devpriv = dev->private;
 624         int i, chan = CR_CHAN(insn->chanspec);
 625
 626         for (i = 0; i < insn->n; i++)
 627                 devpriv->ao_loopbacks[chan] = data[i];
 628
 629         return insn->n;
 630 }
 631
 632 static int waveform_attach(struct comedi_device *dev,
 633                            struct comedi_devconfig *it)
 634 {
 635         struct waveform_private *devpriv;
 636         struct comedi_subdevice *s;
 637         int amplitude = it->options[0];
 638         int period = it->options[1];
 639         int i;
 640         int ret;
 641
 642         devpriv = comedi_alloc_devpriv(dev, sizeof(*devpriv));
 643         if (!devpriv)
 644                 return -ENOMEM;
 645
 646         /* set default amplitude and period */
 647         if (amplitude <= 0)
 648                 amplitude = 1000000;    /* 1 volt */
 649         if (period <= 0)
 650                 period = 100000;        /* 0.1 sec */
 651
 652         devpriv->wf_amplitude = amplitude;
 653         devpriv->wf_period = period;
 654
 655         ret = comedi_alloc_subdevices(dev, 2);
 656         if (ret)
 657                 return ret;
 658
 659         s = &dev->subdevices[0];
 660         dev->read_subdev = s;
 661         /* analog input subdevice */
 662         s->type = COMEDI_SUBD_AI;
 663         s->subdev_flags = SDF_READABLE | SDF_GROUND | SDF_CMD_READ;
 664         s->n_chan = N_CHANS;
 665         s->maxdata = 0xffff;
 666         s->range_table = &waveform_ai_ranges;
 667         s->len_chanlist = s->n_chan * 2;
 668         s->insn_read = waveform_ai_insn_read;
 669         s->do_cmd = waveform_ai_cmd;
 670         s->do_cmdtest = waveform_ai_cmdtest;
 671         s->cancel = waveform_ai_cancel;
 672
 673         s = &dev->subdevices[1];
 674         dev->write_subdev = s;
 675         /* analog output subdevice (loopback) */
 676         s->type = COMEDI_SUBD_AO;
 677         s->subdev_flags = SDF_WRITABLE | SDF_GROUND | SDF_CMD_WRITE;
 678         s->n_chan = N_CHANS;
 679         s->maxdata = 0xffff;
 680         s->range_table = &waveform_ai_ranges;
 681         s->len_chanlist = s->n_chan;
 682         s->insn_write = waveform_ao_insn_write;
 683         s->insn_read = waveform_ai_insn_read;   /* do same as AI insn_read */
 684         s->do_cmd = waveform_ao_cmd;
 685         s->do_cmdtest = waveform_ao_cmdtest;
 686         s->cancel = waveform_ao_cancel;
 687
 688         /* Our default loopback value is just a 0V flatline */
 689         for (i = 0; i < s->n_chan; i++)
 690                 devpriv->ao_loopbacks[i] = s->maxdata / 2;
 691
 692         setup_timer(&devpriv->ai_timer, waveform_ai_timer, (unsigned long)dev);
 693         setup_timer(&devpriv->ao_timer, waveform_ao_timer, (unsigned long)dev);
 694
 695         dev_info(dev->class_dev,
 696                  "%s: %u microvolt, %u microsecond waveform attached\n",
 697                  dev->board_name,
 698                  devpriv->wf_amplitude, devpriv->wf_period);
 699
 700         return 0;
 701 }
 702
 703 static void waveform_detach(struct comedi_device *dev)
 704 {
 705         struct waveform_private *devpriv = dev->private;
 706
 707         if (devpriv) {
 708                 del_timer_sync(&devpriv->ai_timer);
 709                 del_timer_sync(&devpriv->ao_timer);
 710         }
 711 }
 712
 713 static struct comedi_driver waveform_driver = {
 714         .driver_name    = "comedi_test",
 715         .module         = THIS_MODULE,
 716         .attach         = waveform_attach,
 717         .detach         = waveform_detach,
 718 };
 719 module_comedi_driver(waveform_driver);
 720
 721 MODULE_AUTHOR("Comedi http://www.comedi.org");
 722 MODULE_DESCRIPTION("Comedi low-level driver");
 723 MODULE_LICENSE("GPL");