dt2811.c (17782B)
1// SPDX-License-Identifier: GPL-2.0+ 2/* 3 * Comedi driver for Data Translation DT2811 4 * 5 * COMEDI - Linux Control and Measurement Device Interface 6 * Copyright (C) David A. Schleef <ds@schleef.org> 7 */ 8 9/* 10 * Driver: dt2811 11 * Description: Data Translation DT2811 12 * Author: ds 13 * Devices: [Data Translation] DT2811-PGL (dt2811-pgl), DT2811-PGH (dt2811-pgh) 14 * Status: works 15 * 16 * Configuration options: 17 * [0] - I/O port base address 18 * [1] - IRQ (optional, needed for async command support) 19 * [2] - A/D reference (# of analog inputs) 20 * 0 = single-ended (16 channels) 21 * 1 = differential (8 channels) 22 * 2 = pseudo-differential (16 channels) 23 * [3] - A/D range (deprecated, see below) 24 * [4] - D/A 0 range (deprecated, see below) 25 * [5] - D/A 1 range (deprecated, see below) 26 * 27 * Notes: 28 * - A/D ranges are not programmable but the gain is. The AI subdevice has 29 * a range_table containing all the possible analog input range/gain 30 * options for the dt2811-pgh or dt2811-pgl. Use the range that matches 31 * your board configuration and the desired gain to correctly convert 32 * between data values and physical units and to set the correct output 33 * gain. 34 * - D/A ranges are not programmable. The AO subdevice has a range_table 35 * containing all the possible analog output ranges. Use the range 36 * that matches your board configuration to convert between data 37 * values and physical units. 38 */ 39 40#include <linux/module.h> 41#include <linux/interrupt.h> 42#include <linux/delay.h> 43#include <linux/comedi/comedidev.h> 44 45/* 46 * Register I/O map 47 */ 48#define DT2811_ADCSR_REG 0x00 /* r/w A/D Control/Status */ 49#define DT2811_ADCSR_ADDONE BIT(7) /* r 1=A/D conv done */ 50#define DT2811_ADCSR_ADERROR BIT(6) /* r 1=A/D error */ 51#define DT2811_ADCSR_ADBUSY BIT(5) /* r 1=A/D busy */ 52#define DT2811_ADCSR_CLRERROR BIT(4) 53#define DT2811_ADCSR_DMAENB BIT(3) /* r/w 1=dma ena */ 54#define DT2811_ADCSR_INTENB BIT(2) /* r/w 1=interrupts ena */ 55#define DT2811_ADCSR_ADMODE(x) (((x) & 0x3) << 0) 56 57#define DT2811_ADGCR_REG 0x01 /* r/w A/D Gain/Channel */ 58#define DT2811_ADGCR_GAIN(x) (((x) & 0x3) << 6) 59#define DT2811_ADGCR_CHAN(x) (((x) & 0xf) << 0) 60 61#define DT2811_ADDATA_LO_REG 0x02 /* r A/D Data low byte */ 62#define DT2811_ADDATA_HI_REG 0x03 /* r A/D Data high byte */ 63 64#define DT2811_DADATA_LO_REG(x) (0x02 + ((x) * 2)) /* w D/A Data low */ 65#define DT2811_DADATA_HI_REG(x) (0x03 + ((x) * 2)) /* w D/A Data high */ 66 67#define DT2811_DI_REG 0x06 /* r Digital Input Port 0 */ 68#define DT2811_DO_REG 0x06 /* w Digital Output Port 1 */ 69 70#define DT2811_TMRCTR_REG 0x07 /* r/w Timer/Counter */ 71#define DT2811_TMRCTR_MANTISSA(x) (((x) & 0x7) << 3) 72#define DT2811_TMRCTR_EXPONENT(x) (((x) & 0x7) << 0) 73 74#define DT2811_OSC_BASE 1666 /* 600 kHz = 1666.6667ns */ 75 76/* 77 * Timer frequency control: 78 * DT2811_TMRCTR_MANTISSA DT2811_TMRCTR_EXPONENT 79 * val divisor frequency val multiply divisor/divide frequency by 80 * 0 1 600 kHz 0 1 81 * 1 10 60 kHz 1 10 82 * 2 2 300 kHz 2 100 83 * 3 3 200 kHz 3 1000 84 * 4 4 150 kHz 4 10000 85 * 5 5 120 kHz 5 100000 86 * 6 6 100 kHz 6 1000000 87 * 7 12 50 kHz 7 10000000 88 */ 89static const unsigned int dt2811_clk_dividers[] = { 90 1, 10, 2, 3, 4, 5, 6, 12 91}; 92 93static const unsigned int dt2811_clk_multipliers[] = { 94 1, 10, 100, 1000, 10000, 100000, 1000000, 10000000 95}; 96 97/* 98 * The Analog Input range is set using jumpers on the board. 99 * 100 * Input Range W9 W10 101 * -5V to +5V In Out 102 * -2.5V to +2.5V In In 103 * 0V to +5V Out In 104 * 105 * The gain may be set to 1, 2, 4, or 8 (on the dt2811-pgh) or to 106 * 1, 10, 100, 500 (on the dt2811-pgl). 107 */ 108static const struct comedi_lrange dt2811_pgh_ai_ranges = { 109 12, { 110 BIP_RANGE(5), /* range 0: gain=1 */ 111 BIP_RANGE(2.5), /* range 1: gain=2 */ 112 BIP_RANGE(1.25), /* range 2: gain=4 */ 113 BIP_RANGE(0.625), /* range 3: gain=8 */ 114 115 BIP_RANGE(2.5), /* range 0+4: gain=1 */ 116 BIP_RANGE(1.25), /* range 1+4: gain=2 */ 117 BIP_RANGE(0.625), /* range 2+4: gain=4 */ 118 BIP_RANGE(0.3125), /* range 3+4: gain=8 */ 119 120 UNI_RANGE(5), /* range 0+8: gain=1 */ 121 UNI_RANGE(2.5), /* range 1+8: gain=2 */ 122 UNI_RANGE(1.25), /* range 2+8: gain=4 */ 123 UNI_RANGE(0.625) /* range 3+8: gain=8 */ 124 } 125}; 126 127static const struct comedi_lrange dt2811_pgl_ai_ranges = { 128 12, { 129 BIP_RANGE(5), /* range 0: gain=1 */ 130 BIP_RANGE(0.5), /* range 1: gain=10 */ 131 BIP_RANGE(0.05), /* range 2: gain=100 */ 132 BIP_RANGE(0.01), /* range 3: gain=500 */ 133 134 BIP_RANGE(2.5), /* range 0+4: gain=1 */ 135 BIP_RANGE(0.25), /* range 1+4: gain=10 */ 136 BIP_RANGE(0.025), /* range 2+4: gain=100 */ 137 BIP_RANGE(0.005), /* range 3+4: gain=500 */ 138 139 UNI_RANGE(5), /* range 0+8: gain=1 */ 140 UNI_RANGE(0.5), /* range 1+8: gain=10 */ 141 UNI_RANGE(0.05), /* range 2+8: gain=100 */ 142 UNI_RANGE(0.01) /* range 3+8: gain=500 */ 143 } 144}; 145 146/* 147 * The Analog Output range is set per-channel using jumpers on the board. 148 * 149 * DAC0 Jumpers DAC1 Jumpers 150 * Output Range W5 W6 W7 W8 W1 W2 W3 W4 151 * -5V to +5V In Out In Out In Out In Out 152 * -2.5V to +2.5V In Out Out In In Out Out In 153 * 0 to +5V Out In Out In Out In Out In 154 */ 155static const struct comedi_lrange dt2811_ao_ranges = { 156 3, { 157 BIP_RANGE(5), /* default setting from factory */ 158 BIP_RANGE(2.5), 159 UNI_RANGE(5) 160 } 161}; 162 163struct dt2811_board { 164 const char *name; 165 unsigned int is_pgh:1; 166}; 167 168static const struct dt2811_board dt2811_boards[] = { 169 { 170 .name = "dt2811-pgh", 171 .is_pgh = 1, 172 }, { 173 .name = "dt2811-pgl", 174 }, 175}; 176 177struct dt2811_private { 178 unsigned int ai_divisor; 179}; 180 181static unsigned int dt2811_ai_read_sample(struct comedi_device *dev, 182 struct comedi_subdevice *s) 183{ 184 unsigned int val; 185 186 val = inb(dev->iobase + DT2811_ADDATA_LO_REG) | 187 (inb(dev->iobase + DT2811_ADDATA_HI_REG) << 8); 188 189 return val & s->maxdata; 190} 191 192static irqreturn_t dt2811_interrupt(int irq, void *d) 193{ 194 struct comedi_device *dev = d; 195 struct comedi_subdevice *s = dev->read_subdev; 196 struct comedi_async *async = s->async; 197 struct comedi_cmd *cmd = &async->cmd; 198 unsigned int status; 199 200 if (!dev->attached) 201 return IRQ_NONE; 202 203 status = inb(dev->iobase + DT2811_ADCSR_REG); 204 205 if (status & DT2811_ADCSR_ADERROR) { 206 async->events |= COMEDI_CB_OVERFLOW; 207 208 outb(status | DT2811_ADCSR_CLRERROR, 209 dev->iobase + DT2811_ADCSR_REG); 210 } 211 212 if (status & DT2811_ADCSR_ADDONE) { 213 unsigned short val; 214 215 val = dt2811_ai_read_sample(dev, s); 216 comedi_buf_write_samples(s, &val, 1); 217 } 218 219 if (cmd->stop_src == TRIG_COUNT && async->scans_done >= cmd->stop_arg) 220 async->events |= COMEDI_CB_EOA; 221 222 comedi_handle_events(dev, s); 223 224 return IRQ_HANDLED; 225} 226 227static int dt2811_ai_cancel(struct comedi_device *dev, 228 struct comedi_subdevice *s) 229{ 230 /* 231 * Mode 0 232 * Single conversion 233 * 234 * Loading a chanspec will trigger a conversion. 235 */ 236 outb(DT2811_ADCSR_ADMODE(0), dev->iobase + DT2811_ADCSR_REG); 237 238 return 0; 239} 240 241static void dt2811_ai_set_chanspec(struct comedi_device *dev, 242 unsigned int chanspec) 243{ 244 unsigned int chan = CR_CHAN(chanspec); 245 unsigned int range = CR_RANGE(chanspec); 246 247 outb(DT2811_ADGCR_CHAN(chan) | DT2811_ADGCR_GAIN(range), 248 dev->iobase + DT2811_ADGCR_REG); 249} 250 251static int dt2811_ai_cmd(struct comedi_device *dev, 252 struct comedi_subdevice *s) 253{ 254 struct dt2811_private *devpriv = dev->private; 255 struct comedi_cmd *cmd = &s->async->cmd; 256 unsigned int mode; 257 258 if (cmd->start_src == TRIG_NOW) { 259 /* 260 * Mode 1 261 * Continuous conversion, internal trigger and clock 262 * 263 * This resets the trigger flip-flop, disabling A/D strobes. 264 * The timer/counter register is loaded with the division 265 * ratio which will give the required sample rate. 266 * 267 * Loading the first chanspec sets the trigger flip-flop, 268 * enabling the timer/counter. A/D strobes are then generated 269 * at the rate set by the internal clock/divider. 270 */ 271 mode = DT2811_ADCSR_ADMODE(1); 272 } else { /* TRIG_EXT */ 273 if (cmd->convert_src == TRIG_TIMER) { 274 /* 275 * Mode 2 276 * Continuous conversion, external trigger 277 * 278 * Similar to Mode 1, with the exception that the 279 * trigger flip-flop must be set by a negative edge 280 * on the external trigger input. 281 */ 282 mode = DT2811_ADCSR_ADMODE(2); 283 } else { /* TRIG_EXT */ 284 /* 285 * Mode 3 286 * Continuous conversion, external trigger, clock 287 * 288 * Similar to Mode 2, with the exception that the 289 * conversion rate is set by the frequency on the 290 * external clock/divider. 291 */ 292 mode = DT2811_ADCSR_ADMODE(3); 293 } 294 } 295 outb(mode | DT2811_ADCSR_INTENB, dev->iobase + DT2811_ADCSR_REG); 296 297 /* load timer */ 298 outb(devpriv->ai_divisor, dev->iobase + DT2811_TMRCTR_REG); 299 300 /* load chanspec - enables timer */ 301 dt2811_ai_set_chanspec(dev, cmd->chanlist[0]); 302 303 return 0; 304} 305 306static unsigned int dt2811_ns_to_timer(unsigned int *nanosec, 307 unsigned int flags) 308{ 309 unsigned long long ns; 310 unsigned int ns_lo = COMEDI_MIN_SPEED; 311 unsigned int ns_hi = 0; 312 unsigned int divisor_hi = 0; 313 unsigned int divisor_lo = 0; 314 unsigned int _div; 315 unsigned int _mult; 316 317 /* 318 * Work through all the divider/multiplier values to find the two 319 * closest divisors to generate the requested nanosecond timing. 320 */ 321 for (_div = 0; _div <= 7; _div++) { 322 for (_mult = 0; _mult <= 7; _mult++) { 323 unsigned int div = dt2811_clk_dividers[_div]; 324 unsigned int mult = dt2811_clk_multipliers[_mult]; 325 unsigned long long divider = div * mult; 326 unsigned int divisor = DT2811_TMRCTR_MANTISSA(_div) | 327 DT2811_TMRCTR_EXPONENT(_mult); 328 329 /* 330 * The timer can be configured to run at a slowest 331 * speed of 0.005hz (600 Khz/120000000), which requires 332 * 37-bits to represent the nanosecond value. Limit the 333 * slowest timing to what comedi handles (32-bits). 334 */ 335 ns = divider * DT2811_OSC_BASE; 336 if (ns > COMEDI_MIN_SPEED) 337 continue; 338 339 /* Check for fastest found timing */ 340 if (ns <= *nanosec && ns > ns_hi) { 341 ns_hi = ns; 342 divisor_hi = divisor; 343 } 344 /* Check for slowest found timing */ 345 if (ns >= *nanosec && ns < ns_lo) { 346 ns_lo = ns; 347 divisor_lo = divisor; 348 } 349 } 350 } 351 352 /* 353 * The slowest found timing will be invalid if the requested timing 354 * is faster than what can be generated by the timer. Fix it so that 355 * CMDF_ROUND_UP returns valid timing. 356 */ 357 if (ns_lo == COMEDI_MIN_SPEED) { 358 ns_lo = ns_hi; 359 divisor_lo = divisor_hi; 360 } 361 /* 362 * The fastest found timing will be invalid if the requested timing 363 * is less than what can be generated by the timer. Fix it so that 364 * CMDF_ROUND_NEAREST and CMDF_ROUND_DOWN return valid timing. 365 */ 366 if (ns_hi == 0) { 367 ns_hi = ns_lo; 368 divisor_hi = divisor_lo; 369 } 370 371 switch (flags & CMDF_ROUND_MASK) { 372 case CMDF_ROUND_NEAREST: 373 default: 374 if (ns_hi - *nanosec < *nanosec - ns_lo) { 375 *nanosec = ns_lo; 376 return divisor_lo; 377 } 378 *nanosec = ns_hi; 379 return divisor_hi; 380 case CMDF_ROUND_UP: 381 *nanosec = ns_lo; 382 return divisor_lo; 383 case CMDF_ROUND_DOWN: 384 *nanosec = ns_hi; 385 return divisor_hi; 386 } 387} 388 389static int dt2811_ai_cmdtest(struct comedi_device *dev, 390 struct comedi_subdevice *s, 391 struct comedi_cmd *cmd) 392{ 393 struct dt2811_private *devpriv = dev->private; 394 unsigned int arg; 395 int err = 0; 396 397 /* Step 1 : check if triggers are trivially valid */ 398 399 err |= comedi_check_trigger_src(&cmd->start_src, TRIG_NOW | TRIG_EXT); 400 err |= comedi_check_trigger_src(&cmd->scan_begin_src, TRIG_FOLLOW); 401 err |= comedi_check_trigger_src(&cmd->convert_src, 402 TRIG_TIMER | TRIG_EXT); 403 err |= comedi_check_trigger_src(&cmd->scan_end_src, TRIG_COUNT); 404 err |= comedi_check_trigger_src(&cmd->stop_src, TRIG_COUNT | TRIG_NONE); 405 406 if (err) 407 return 1; 408 409 /* Step 2a : make sure trigger sources are unique */ 410 411 err |= comedi_check_trigger_is_unique(cmd->start_src); 412 err |= comedi_check_trigger_is_unique(cmd->convert_src); 413 err |= comedi_check_trigger_is_unique(cmd->stop_src); 414 415 /* Step 2b : and mutually compatible */ 416 417 if (cmd->convert_src == TRIG_EXT && cmd->start_src != TRIG_EXT) 418 err |= -EINVAL; 419 420 if (err) 421 return 2; 422 423 /* Step 3: check if arguments are trivially valid */ 424 425 err |= comedi_check_trigger_arg_is(&cmd->start_arg, 0); 426 err |= comedi_check_trigger_arg_is(&cmd->scan_begin_arg, 0); 427 if (cmd->convert_src == TRIG_TIMER) 428 err |= comedi_check_trigger_arg_min(&cmd->convert_arg, 12500); 429 err |= comedi_check_trigger_arg_is(&cmd->scan_end_arg, 430 cmd->chanlist_len); 431 if (cmd->stop_src == TRIG_COUNT) 432 err |= comedi_check_trigger_arg_min(&cmd->stop_arg, 1); 433 else /* TRIG_NONE */ 434 err |= comedi_check_trigger_arg_is(&cmd->stop_arg, 0); 435 436 if (err) 437 return 3; 438 439 /* Step 4: fix up any arguments */ 440 441 if (cmd->convert_src == TRIG_TIMER) { 442 arg = cmd->convert_arg; 443 devpriv->ai_divisor = dt2811_ns_to_timer(&arg, cmd->flags); 444 err |= comedi_check_trigger_arg_is(&cmd->convert_arg, arg); 445 } else { /* TRIG_EXT */ 446 /* The convert_arg is used to set the divisor. */ 447 devpriv->ai_divisor = cmd->convert_arg; 448 } 449 450 if (err) 451 return 4; 452 453 /* Step 5: check channel list if it exists */ 454 455 return 0; 456} 457 458static int dt2811_ai_eoc(struct comedi_device *dev, 459 struct comedi_subdevice *s, 460 struct comedi_insn *insn, 461 unsigned long context) 462{ 463 unsigned int status; 464 465 status = inb(dev->iobase + DT2811_ADCSR_REG); 466 if ((status & DT2811_ADCSR_ADBUSY) == 0) 467 return 0; 468 return -EBUSY; 469} 470 471static int dt2811_ai_insn_read(struct comedi_device *dev, 472 struct comedi_subdevice *s, 473 struct comedi_insn *insn, 474 unsigned int *data) 475{ 476 int ret; 477 int i; 478 479 /* We will already be in Mode 0 */ 480 for (i = 0; i < insn->n; i++) { 481 /* load chanspec and trigger conversion */ 482 dt2811_ai_set_chanspec(dev, insn->chanspec); 483 484 ret = comedi_timeout(dev, s, insn, dt2811_ai_eoc, 0); 485 if (ret) 486 return ret; 487 488 data[i] = dt2811_ai_read_sample(dev, s); 489 } 490 491 return insn->n; 492} 493 494static int dt2811_ao_insn_write(struct comedi_device *dev, 495 struct comedi_subdevice *s, 496 struct comedi_insn *insn, 497 unsigned int *data) 498{ 499 unsigned int chan = CR_CHAN(insn->chanspec); 500 unsigned int val = s->readback[chan]; 501 int i; 502 503 for (i = 0; i < insn->n; i++) { 504 val = data[i]; 505 outb(val & 0xff, dev->iobase + DT2811_DADATA_LO_REG(chan)); 506 outb((val >> 8) & 0xff, 507 dev->iobase + DT2811_DADATA_HI_REG(chan)); 508 } 509 s->readback[chan] = val; 510 511 return insn->n; 512} 513 514static int dt2811_di_insn_bits(struct comedi_device *dev, 515 struct comedi_subdevice *s, 516 struct comedi_insn *insn, 517 unsigned int *data) 518{ 519 data[1] = inb(dev->iobase + DT2811_DI_REG); 520 521 return insn->n; 522} 523 524static int dt2811_do_insn_bits(struct comedi_device *dev, 525 struct comedi_subdevice *s, 526 struct comedi_insn *insn, 527 unsigned int *data) 528{ 529 if (comedi_dio_update_state(s, data)) 530 outb(s->state, dev->iobase + DT2811_DO_REG); 531 532 data[1] = s->state; 533 534 return insn->n; 535} 536 537static void dt2811_reset(struct comedi_device *dev) 538{ 539 /* This is the initialization sequence from the users manual */ 540 outb(DT2811_ADCSR_ADMODE(0), dev->iobase + DT2811_ADCSR_REG); 541 usleep_range(100, 1000); 542 inb(dev->iobase + DT2811_ADDATA_LO_REG); 543 inb(dev->iobase + DT2811_ADDATA_HI_REG); 544 outb(DT2811_ADCSR_ADMODE(0) | DT2811_ADCSR_CLRERROR, 545 dev->iobase + DT2811_ADCSR_REG); 546} 547 548static int dt2811_attach(struct comedi_device *dev, struct comedi_devconfig *it) 549{ 550 const struct dt2811_board *board = dev->board_ptr; 551 struct dt2811_private *devpriv; 552 struct comedi_subdevice *s; 553 int ret; 554 555 devpriv = comedi_alloc_devpriv(dev, sizeof(*devpriv)); 556 if (!devpriv) 557 return -ENOMEM; 558 559 ret = comedi_request_region(dev, it->options[0], 0x8); 560 if (ret) 561 return ret; 562 563 dt2811_reset(dev); 564 565 /* IRQ's 2,3,5,7 are valid for async command support */ 566 if (it->options[1] <= 7 && (BIT(it->options[1]) & 0xac)) { 567 ret = request_irq(it->options[1], dt2811_interrupt, 0, 568 dev->board_name, dev); 569 if (ret == 0) 570 dev->irq = it->options[1]; 571 } 572 573 ret = comedi_alloc_subdevices(dev, 4); 574 if (ret) 575 return ret; 576 577 /* Analog Input subdevice */ 578 s = &dev->subdevices[0]; 579 s->type = COMEDI_SUBD_AI; 580 s->subdev_flags = SDF_READABLE | 581 ((it->options[2] == 1) ? SDF_DIFF : 582 (it->options[2] == 2) ? SDF_COMMON : SDF_GROUND); 583 s->n_chan = (it->options[2] == 1) ? 8 : 16; 584 s->maxdata = 0x0fff; 585 s->range_table = board->is_pgh ? &dt2811_pgh_ai_ranges 586 : &dt2811_pgl_ai_ranges; 587 s->insn_read = dt2811_ai_insn_read; 588 if (dev->irq) { 589 dev->read_subdev = s; 590 s->subdev_flags |= SDF_CMD_READ; 591 s->len_chanlist = 1; 592 s->do_cmdtest = dt2811_ai_cmdtest; 593 s->do_cmd = dt2811_ai_cmd; 594 s->cancel = dt2811_ai_cancel; 595 } 596 597 /* Analog Output subdevice */ 598 s = &dev->subdevices[1]; 599 s->type = COMEDI_SUBD_AO; 600 s->subdev_flags = SDF_WRITABLE; 601 s->n_chan = 2; 602 s->maxdata = 0x0fff; 603 s->range_table = &dt2811_ao_ranges; 604 s->insn_write = dt2811_ao_insn_write; 605 606 ret = comedi_alloc_subdev_readback(s); 607 if (ret) 608 return ret; 609 610 /* Digital Input subdevice */ 611 s = &dev->subdevices[2]; 612 s->type = COMEDI_SUBD_DI; 613 s->subdev_flags = SDF_READABLE; 614 s->n_chan = 8; 615 s->maxdata = 1; 616 s->range_table = &range_digital; 617 s->insn_bits = dt2811_di_insn_bits; 618 619 /* Digital Output subdevice */ 620 s = &dev->subdevices[3]; 621 s->type = COMEDI_SUBD_DO; 622 s->subdev_flags = SDF_WRITABLE; 623 s->n_chan = 8; 624 s->maxdata = 1; 625 s->range_table = &range_digital; 626 s->insn_bits = dt2811_do_insn_bits; 627 628 return 0; 629} 630 631static struct comedi_driver dt2811_driver = { 632 .driver_name = "dt2811", 633 .module = THIS_MODULE, 634 .attach = dt2811_attach, 635 .detach = comedi_legacy_detach, 636 .board_name = &dt2811_boards[0].name, 637 .num_names = ARRAY_SIZE(dt2811_boards), 638 .offset = sizeof(struct dt2811_board), 639}; 640module_comedi_driver(dt2811_driver); 641 642MODULE_AUTHOR("Comedi https://www.comedi.org"); 643MODULE_DESCRIPTION("Comedi driver for Data Translation DT2811 series boards"); 644MODULE_LICENSE("GPL");