1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Support code for Analog Devices Sigma-Delta ADCs 4 * 5 * Copyright 2012 Analog Devices Inc. 6 * Author: Lars-Peter Clausen <lars@metafoo.de> 7 */ 8 9 #include <linux/align.h> 10 #include <linux/bitmap.h> 11 #include <linux/bitops.h> 12 #include <linux/cleanup.h> 13 #include <linux/completion.h> 14 #include <linux/device.h> 15 #include <linux/err.h> 16 #include <linux/export.h> 17 #include <linux/find.h> 18 #include <linux/gpio/consumer.h> 19 #include <linux/interrupt.h> 20 #include <linux/module.h> 21 #include <linux/property.h> 22 #include <linux/slab.h> 23 #include <linux/spi/offload/consumer.h> 24 #include <linux/spi/spi.h> 25 #include <linux/spinlock.h> 26 #include <linux/string.h> 27 #include <linux/types.h> 28 #include <linux/unaligned.h> 29 30 #include <linux/iio/adc/ad_sigma_delta.h> 31 #include <linux/iio/buffer-dmaengine.h> 32 #include <linux/iio/buffer.h> 33 #include <linux/iio/iio.h> 34 #include <linux/iio/trigger_consumer.h> 35 #include <linux/iio/trigger.h> 36 #include <linux/iio/triggered_buffer.h> 37 38 #define AD_SD_COMM_CHAN_MASK 0x3 39 40 #define AD_SD_REG_COMM 0x00 41 #define AD_SD_REG_STATUS 0x00 42 #define AD_SD_REG_DATA 0x03 43 44 #define AD_SD_REG_STATUS_RDY 0x80 45 46 /** 47 * ad_sd_set_comm() - Set communications register 48 * 49 * @sigma_delta: The sigma delta device 50 * @comm: New value for the communications register 51 */ 52 void ad_sd_set_comm(struct ad_sigma_delta *sigma_delta, u8 comm) 53 { 54 /* Some variants use the lower two bits of the communications register 55 * to select the channel */ 56 sigma_delta->comm = comm & AD_SD_COMM_CHAN_MASK; 57 } 58 EXPORT_SYMBOL_NS_GPL(ad_sd_set_comm, "IIO_AD_SIGMA_DELTA"); 59 60 /** 61 * ad_sd_write_reg() - Write a register 62 * 63 * @sigma_delta: The sigma delta device 64 * @reg: Address of the register 65 * @size: Size of the register (0-3) 66 * @val: Value to write to the register 67 * 68 * Returns 0 on success, an error code otherwise. 69 **/ 70 int ad_sd_write_reg(struct ad_sigma_delta *sigma_delta, unsigned int reg, 71 unsigned int size, unsigned int val) 72 { 73 u8 *data = sigma_delta->tx_buf; 74 struct spi_transfer t = { 75 .tx_buf = data, 76 .len = size + 1, 77 .cs_change = sigma_delta->keep_cs_asserted, 78 }; 79 struct spi_message m; 80 int ret; 81 82 data[0] = (reg << sigma_delta->info->addr_shift) | sigma_delta->comm; 83 84 switch (size) { 85 case 3: 86 put_unaligned_be24(val, &data[1]); 87 break; 88 case 2: 89 put_unaligned_be16(val, &data[1]); 90 break; 91 case 1: 92 data[1] = val; 93 break; 94 case 0: 95 break; 96 default: 97 return -EINVAL; 98 } 99 100 spi_message_init(&m); 101 spi_message_add_tail(&t, &m); 102 103 if (sigma_delta->bus_locked) 104 ret = spi_sync_locked(sigma_delta->spi, &m); 105 else 106 ret = spi_sync(sigma_delta->spi, &m); 107 108 return ret; 109 } 110 EXPORT_SYMBOL_NS_GPL(ad_sd_write_reg, "IIO_AD_SIGMA_DELTA"); 111 112 static void ad_sd_set_read_reg_addr(struct ad_sigma_delta *sigma_delta, u8 reg, 113 u8 *data) 114 { 115 data[0] = reg << sigma_delta->info->addr_shift; 116 data[0] |= sigma_delta->info->read_mask; 117 data[0] |= sigma_delta->comm; 118 } 119 120 static int ad_sd_read_reg_raw(struct ad_sigma_delta *sigma_delta, 121 unsigned int reg, unsigned int size, u8 *val) 122 { 123 u8 *data = sigma_delta->tx_buf; 124 int ret; 125 struct spi_transfer t[] = { 126 { 127 .tx_buf = data, 128 .len = 1, 129 }, { 130 .rx_buf = val, 131 .len = size, 132 .cs_change = sigma_delta->keep_cs_asserted, 133 }, 134 }; 135 struct spi_message m; 136 137 spi_message_init(&m); 138 139 if (sigma_delta->info->has_registers) { 140 ad_sd_set_read_reg_addr(sigma_delta, reg, data); 141 spi_message_add_tail(&t[0], &m); 142 } 143 spi_message_add_tail(&t[1], &m); 144 145 if (sigma_delta->bus_locked) 146 ret = spi_sync_locked(sigma_delta->spi, &m); 147 else 148 ret = spi_sync(sigma_delta->spi, &m); 149 150 return ret; 151 } 152 153 /** 154 * ad_sd_read_reg() - Read a register 155 * 156 * @sigma_delta: The sigma delta device 157 * @reg: Address of the register 158 * @size: Size of the register (1-4) 159 * @val: Read value 160 * 161 * Returns 0 on success, an error code otherwise. 162 **/ 163 int ad_sd_read_reg(struct ad_sigma_delta *sigma_delta, 164 unsigned int reg, unsigned int size, unsigned int *val) 165 { 166 int ret; 167 168 ret = ad_sd_read_reg_raw(sigma_delta, reg, size, sigma_delta->rx_buf); 169 if (ret < 0) 170 goto out; 171 172 switch (size) { 173 case 4: 174 *val = get_unaligned_be32(sigma_delta->rx_buf); 175 break; 176 case 3: 177 *val = get_unaligned_be24(sigma_delta->rx_buf); 178 break; 179 case 2: 180 *val = get_unaligned_be16(sigma_delta->rx_buf); 181 break; 182 case 1: 183 *val = sigma_delta->rx_buf[0]; 184 break; 185 default: 186 ret = -EINVAL; 187 break; 188 } 189 190 out: 191 return ret; 192 } 193 EXPORT_SYMBOL_NS_GPL(ad_sd_read_reg, "IIO_AD_SIGMA_DELTA"); 194 195 /** 196 * ad_sd_reset() - Reset the serial interface 197 * 198 * @sigma_delta: The sigma delta device 199 * 200 * Returns 0 on success, an error code otherwise. 201 **/ 202 int ad_sd_reset(struct ad_sigma_delta *sigma_delta) 203 { 204 unsigned int reset_length = sigma_delta->info->num_resetclks; 205 unsigned int size; 206 u8 *buf; 207 int ret; 208 209 size = BITS_TO_BYTES(reset_length); 210 buf = kcalloc(size, sizeof(*buf), GFP_KERNEL); 211 if (!buf) 212 return -ENOMEM; 213 214 memset(buf, 0xff, size); 215 ret = spi_write(sigma_delta->spi, buf, size); 216 kfree(buf); 217 218 return ret; 219 } 220 EXPORT_SYMBOL_NS_GPL(ad_sd_reset, "IIO_AD_SIGMA_DELTA"); 221 222 static bool ad_sd_disable_irq(struct ad_sigma_delta *sigma_delta) 223 { 224 guard(spinlock_irqsave)(&sigma_delta->irq_lock); 225 226 /* It's already off, return false to indicate nothing was changed */ 227 if (sigma_delta->irq_dis) 228 return false; 229 230 sigma_delta->irq_dis = true; 231 disable_irq_nosync(sigma_delta->irq_line); 232 return true; 233 } 234 235 static void ad_sd_enable_irq(struct ad_sigma_delta *sigma_delta) 236 { 237 guard(spinlock_irqsave)(&sigma_delta->irq_lock); 238 239 sigma_delta->irq_dis = false; 240 enable_irq(sigma_delta->irq_line); 241 } 242 243 #define AD_SD_CLEAR_DATA_BUFLEN 9 244 245 /* Called with `sigma_delta->bus_locked == true` only. */ 246 static int ad_sigma_delta_clear_pending_event(struct ad_sigma_delta *sigma_delta) 247 { 248 bool pending_event; 249 unsigned int data_read_len = BITS_TO_BYTES(sigma_delta->info->num_resetclks); 250 u8 *data; 251 struct spi_transfer t[] = { 252 { 253 .len = 1, 254 }, { 255 .len = data_read_len, 256 } 257 }; 258 struct spi_message m; 259 int ret; 260 261 /* 262 * Read R̅D̅Y̅ pin (if possible) or status register to check if there is an 263 * old event. 264 */ 265 if (sigma_delta->rdy_gpiod) { 266 pending_event = gpiod_get_value(sigma_delta->rdy_gpiod); 267 } else { 268 unsigned int status_reg; 269 270 ret = ad_sd_read_reg(sigma_delta, AD_SD_REG_STATUS, 1, &status_reg); 271 if (ret) 272 return ret; 273 274 pending_event = !(status_reg & AD_SD_REG_STATUS_RDY); 275 } 276 277 if (!pending_event) 278 return 0; 279 280 /* 281 * In general the size of the data register is unknown. It varies from 282 * device to device, might be one byte longer if CONTROL.DATA_STATUS is 283 * set and even varies on some devices depending on which input is 284 * selected. So send one byte to start reading the data register and 285 * then just clock for some bytes with DIN (aka MOSI) high to not 286 * confuse the register access state machine after the data register was 287 * completely read. Note however that the sequence length must be 288 * shorter than the reset procedure. 289 */ 290 291 data = kzalloc(data_read_len + 1, GFP_KERNEL); 292 if (!data) 293 return -ENOMEM; 294 295 spi_message_init(&m); 296 if (sigma_delta->info->has_registers) { 297 unsigned int data_reg = sigma_delta->info->data_reg ?: AD_SD_REG_DATA; 298 299 ad_sd_set_read_reg_addr(sigma_delta, data_reg, data); 300 t[0].tx_buf = data; 301 spi_message_add_tail(&t[0], &m); 302 } 303 304 /* 305 * The first transferred byte is part of the real data register, 306 * so this doesn't need to be 0xff. In the remaining 307 * `data_read_len - 1` bytes are less than $num_resetclks ones. 308 */ 309 t[1].tx_buf = data + 1; 310 data[1] = 0x00; 311 memset(data + 2, 0xff, data_read_len - 1); 312 spi_message_add_tail(&t[1], &m); 313 314 ret = spi_sync_locked(sigma_delta->spi, &m); 315 316 kfree(data); 317 318 return ret; 319 } 320 321 int ad_sd_calibrate(struct ad_sigma_delta *sigma_delta, 322 unsigned int mode, unsigned int channel) 323 { 324 int ret; 325 unsigned long time_left; 326 327 ret = ad_sigma_delta_set_channel(sigma_delta, channel); 328 if (ret) 329 return ret; 330 331 spi_bus_lock(sigma_delta->spi->controller); 332 sigma_delta->bus_locked = true; 333 sigma_delta->keep_cs_asserted = true; 334 reinit_completion(&sigma_delta->completion); 335 336 ret = ad_sigma_delta_clear_pending_event(sigma_delta); 337 if (ret) 338 goto out; 339 340 ret = ad_sigma_delta_set_mode(sigma_delta, mode); 341 if (ret < 0) 342 goto out; 343 344 ad_sd_enable_irq(sigma_delta); 345 time_left = wait_for_completion_timeout(&sigma_delta->completion, 2 * HZ); 346 if (time_left == 0) { 347 ad_sd_disable_irq(sigma_delta); 348 ret = -EIO; 349 } else { 350 ret = 0; 351 } 352 out: 353 sigma_delta->keep_cs_asserted = false; 354 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE); 355 ad_sigma_delta_disable_one(sigma_delta, channel); 356 sigma_delta->bus_locked = false; 357 spi_bus_unlock(sigma_delta->spi->controller); 358 359 return ret; 360 } 361 EXPORT_SYMBOL_NS_GPL(ad_sd_calibrate, "IIO_AD_SIGMA_DELTA"); 362 363 /** 364 * ad_sd_calibrate_all() - Performs channel calibration 365 * @sigma_delta: The sigma delta device 366 * @cb: Array of channels and calibration type to perform 367 * @n: Number of items in cb 368 * 369 * Returns 0 on success, an error code otherwise. 370 **/ 371 int ad_sd_calibrate_all(struct ad_sigma_delta *sigma_delta, 372 const struct ad_sd_calib_data *cb, unsigned int n) 373 { 374 unsigned int i; 375 int ret; 376 377 for (i = 0; i < n; i++) { 378 ret = ad_sd_calibrate(sigma_delta, cb[i].mode, cb[i].channel); 379 if (ret) 380 return ret; 381 } 382 383 return 0; 384 } 385 EXPORT_SYMBOL_NS_GPL(ad_sd_calibrate_all, "IIO_AD_SIGMA_DELTA"); 386 387 /** 388 * ad_sigma_delta_single_conversion() - Performs a single data conversion 389 * @indio_dev: The IIO device 390 * @chan: The conversion is done for this channel 391 * @val: Pointer to the location where to store the read value 392 * 393 * Returns: 0 on success, an error value otherwise. 394 */ 395 int ad_sigma_delta_single_conversion(struct iio_dev *indio_dev, 396 const struct iio_chan_spec *chan, int *val) 397 { 398 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 399 unsigned int sample, raw_sample; 400 unsigned int data_reg; 401 int ret = 0; 402 403 if (!iio_device_claim_direct(indio_dev)) 404 return -EBUSY; 405 406 ret = ad_sigma_delta_set_channel(sigma_delta, chan->address); 407 if (ret) 408 goto out_release; 409 410 spi_bus_lock(sigma_delta->spi->controller); 411 sigma_delta->bus_locked = true; 412 sigma_delta->keep_cs_asserted = true; 413 reinit_completion(&sigma_delta->completion); 414 415 ret = ad_sigma_delta_clear_pending_event(sigma_delta); 416 if (ret) 417 goto out_unlock; 418 419 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_SINGLE); 420 421 ad_sd_enable_irq(sigma_delta); 422 ret = wait_for_completion_interruptible_timeout( 423 &sigma_delta->completion, HZ); 424 425 if (ret == 0) 426 ret = -EIO; 427 if (ret < 0) 428 goto out; 429 430 if (sigma_delta->info->data_reg != 0) 431 data_reg = sigma_delta->info->data_reg; 432 else 433 data_reg = AD_SD_REG_DATA; 434 435 ret = ad_sd_read_reg(sigma_delta, data_reg, 436 BITS_TO_BYTES(chan->scan_type.realbits + chan->scan_type.shift), 437 &raw_sample); 438 439 out: 440 ad_sd_disable_irq(sigma_delta); 441 442 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE); 443 ad_sigma_delta_disable_one(sigma_delta, chan->address); 444 445 out_unlock: 446 sigma_delta->keep_cs_asserted = false; 447 sigma_delta->bus_locked = false; 448 spi_bus_unlock(sigma_delta->spi->controller); 449 out_release: 450 iio_device_release_direct(indio_dev); 451 452 if (ret) 453 return ret; 454 455 sample = raw_sample >> chan->scan_type.shift; 456 sample &= (1 << chan->scan_type.realbits) - 1; 457 *val = sample; 458 459 ret = ad_sigma_delta_postprocess_sample(sigma_delta, raw_sample); 460 if (ret) 461 return ret; 462 463 return IIO_VAL_INT; 464 } 465 EXPORT_SYMBOL_NS_GPL(ad_sigma_delta_single_conversion, "IIO_AD_SIGMA_DELTA"); 466 467 static int ad_sd_buffer_postenable(struct iio_dev *indio_dev) 468 { 469 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 470 const struct iio_scan_type *scan_type = &indio_dev->channels[0].scan_type; 471 struct spi_transfer *xfer = sigma_delta->sample_xfer; 472 unsigned int i, slot, channel; 473 u8 *samples_buf; 474 int ret; 475 476 if (sigma_delta->num_slots == 1) { 477 channel = find_first_bit(indio_dev->active_scan_mask, 478 iio_get_masklength(indio_dev)); 479 ret = ad_sigma_delta_set_channel(sigma_delta, 480 indio_dev->channels[channel].address); 481 if (ret) 482 return ret; 483 slot = 1; 484 } else { 485 /* 486 * At this point update_scan_mode already enabled the required channels. 487 * For sigma-delta sequencer drivers with multiple slots, an update_scan_mode 488 * implementation is mandatory. 489 */ 490 slot = 0; 491 iio_for_each_active_channel(indio_dev, i) { 492 sigma_delta->slots[slot] = indio_dev->channels[i].address; 493 slot++; 494 } 495 } 496 497 sigma_delta->active_slots = slot; 498 sigma_delta->current_slot = 0; 499 500 if (ad_sigma_delta_has_spi_offload(sigma_delta)) { 501 xfer[1].offload_flags = SPI_OFFLOAD_XFER_RX_STREAM; 502 xfer[1].bits_per_word = scan_type->realbits; 503 xfer[1].len = spi_bpw_to_bytes(scan_type->realbits); 504 } else { 505 unsigned int samples_buf_size, scan_size; 506 507 if (sigma_delta->active_slots > 1) { 508 ret = ad_sigma_delta_append_status(sigma_delta, true); 509 if (ret) 510 return ret; 511 } 512 513 samples_buf_size = 514 ALIGN(slot * BITS_TO_BYTES(scan_type->storagebits), 515 sizeof(s64)); 516 samples_buf_size += sizeof(s64); 517 samples_buf = devm_krealloc(&sigma_delta->spi->dev, 518 sigma_delta->samples_buf, 519 samples_buf_size, GFP_KERNEL); 520 if (!samples_buf) 521 return -ENOMEM; 522 523 sigma_delta->samples_buf = samples_buf; 524 scan_size = BITS_TO_BYTES(scan_type->realbits + scan_type->shift); 525 /* For 24-bit data, there is an extra byte of padding. */ 526 xfer[1].rx_buf = &sigma_delta->rx_buf[scan_size == 3 ? 1 : 0]; 527 xfer[1].len = scan_size + (sigma_delta->status_appended ? 1 : 0); 528 } 529 xfer[1].cs_change = 1; 530 531 if (sigma_delta->info->has_registers) { 532 xfer[0].tx_buf = &sigma_delta->sample_addr; 533 xfer[0].len = 1; 534 535 ad_sd_set_read_reg_addr(sigma_delta, 536 sigma_delta->info->data_reg ?: AD_SD_REG_DATA, 537 &sigma_delta->sample_addr); 538 spi_message_init_with_transfers(&sigma_delta->sample_msg, xfer, 2); 539 } else { 540 spi_message_init_with_transfers(&sigma_delta->sample_msg, 541 &xfer[1], 1); 542 } 543 544 sigma_delta->sample_msg.offload = sigma_delta->offload; 545 546 ret = spi_optimize_message(sigma_delta->spi, &sigma_delta->sample_msg); 547 if (ret) 548 return ret; 549 550 spi_bus_lock(sigma_delta->spi->controller); 551 sigma_delta->bus_locked = true; 552 sigma_delta->keep_cs_asserted = true; 553 554 ret = ad_sigma_delta_clear_pending_event(sigma_delta); 555 if (ret) 556 goto err_unlock; 557 558 ret = ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_CONTINUOUS); 559 if (ret) 560 goto err_unlock; 561 562 if (ad_sigma_delta_has_spi_offload(sigma_delta)) { 563 struct spi_offload_trigger_config config = { 564 .type = SPI_OFFLOAD_TRIGGER_DATA_READY, 565 }; 566 567 ret = spi_offload_trigger_enable(sigma_delta->offload, 568 sigma_delta->offload_trigger, 569 &config); 570 if (ret) 571 goto err_unlock; 572 } else { 573 ad_sd_enable_irq(sigma_delta); 574 } 575 576 return 0; 577 578 err_unlock: 579 spi_bus_unlock(sigma_delta->spi->controller); 580 spi_unoptimize_message(&sigma_delta->sample_msg); 581 582 return ret; 583 } 584 585 static int ad_sd_buffer_predisable(struct iio_dev *indio_dev) 586 { 587 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 588 589 if (ad_sigma_delta_has_spi_offload(sigma_delta)) { 590 spi_offload_trigger_disable(sigma_delta->offload, 591 sigma_delta->offload_trigger); 592 } else { 593 reinit_completion(&sigma_delta->completion); 594 wait_for_completion_timeout(&sigma_delta->completion, HZ); 595 596 ad_sd_disable_irq(sigma_delta); 597 } 598 599 sigma_delta->keep_cs_asserted = false; 600 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE); 601 602 if (sigma_delta->status_appended) 603 ad_sigma_delta_append_status(sigma_delta, false); 604 605 ad_sigma_delta_disable_all(sigma_delta); 606 sigma_delta->bus_locked = false; 607 spi_bus_unlock(sigma_delta->spi->controller); 608 spi_unoptimize_message(&sigma_delta->sample_msg); 609 610 return 0; 611 } 612 613 static irqreturn_t ad_sd_trigger_handler(int irq, void *p) 614 { 615 struct iio_poll_func *pf = p; 616 struct iio_dev *indio_dev = pf->indio_dev; 617 const struct iio_scan_type *scan_type = &indio_dev->channels[0].scan_type; 618 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 619 u8 *data = sigma_delta->rx_buf; 620 unsigned int sample_size; 621 unsigned int sample_pos; 622 unsigned int status_pos; 623 unsigned int reg_size; 624 int ret; 625 626 reg_size = BITS_TO_BYTES(scan_type->realbits + scan_type->shift); 627 /* For 24-bit data, there is an extra byte of padding. */ 628 status_pos = reg_size + (reg_size == 3 ? 1 : 0); 629 630 ret = spi_sync_locked(sigma_delta->spi, &sigma_delta->sample_msg); 631 if (ret) 632 goto irq_handled; 633 634 /* 635 * For devices sampling only one channel at 636 * once, there is no need for sample number tracking. 637 */ 638 if (sigma_delta->active_slots == 1) { 639 iio_push_to_buffers_with_timestamp(indio_dev, data, pf->timestamp); 640 goto irq_handled; 641 } 642 643 if (sigma_delta->status_appended) { 644 u8 converted_channel; 645 646 converted_channel = data[status_pos] & sigma_delta->info->status_ch_mask; 647 if (converted_channel != sigma_delta->slots[sigma_delta->current_slot]) { 648 /* 649 * Desync occurred during continuous sampling of multiple channels. 650 * Drop this incomplete sample and start from first channel again. 651 */ 652 653 sigma_delta->current_slot = 0; 654 goto irq_handled; 655 } 656 } 657 658 sample_size = BITS_TO_BYTES(scan_type->storagebits); 659 sample_pos = sample_size * sigma_delta->current_slot; 660 memcpy(&sigma_delta->samples_buf[sample_pos], data, sample_size); 661 sigma_delta->current_slot++; 662 663 if (sigma_delta->current_slot == sigma_delta->active_slots) { 664 sigma_delta->current_slot = 0; 665 iio_push_to_buffers_with_timestamp(indio_dev, sigma_delta->samples_buf, 666 pf->timestamp); 667 } 668 669 irq_handled: 670 iio_trigger_notify_done(indio_dev->trig); 671 ad_sd_enable_irq(sigma_delta); 672 673 return IRQ_HANDLED; 674 } 675 676 static bool ad_sd_validate_scan_mask(struct iio_dev *indio_dev, const unsigned long *mask) 677 { 678 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 679 680 return bitmap_weight(mask, iio_get_masklength(indio_dev)) <= sigma_delta->num_slots; 681 } 682 683 static const struct iio_buffer_setup_ops ad_sd_buffer_setup_ops = { 684 .postenable = &ad_sd_buffer_postenable, 685 .predisable = &ad_sd_buffer_predisable, 686 .validate_scan_mask = &ad_sd_validate_scan_mask, 687 }; 688 689 static irqreturn_t ad_sd_data_rdy_trig_poll(int irq, void *private) 690 { 691 struct ad_sigma_delta *sigma_delta = private; 692 693 /* 694 * AD7124 and a few others use the same physical line for interrupt 695 * reporting (R̅D̅Y̅) and MISO. 696 * As MISO toggles when reading a register, this likely results in a 697 * pending interrupt. This has two consequences: a) The irq might 698 * trigger immediately after it's enabled even though the conversion 699 * isn't done yet; and b) checking the STATUS register's R̅D̅Y̅ flag is 700 * off-limits as reading that would trigger another irq event. 701 * 702 * So read the MOSI line as GPIO (if available) and only trigger the irq 703 * if the line is active. Without such a GPIO assume this is a valid 704 * interrupt. 705 * 706 * Also as disable_irq_nosync() is used to disable the irq, only act if 707 * the irq wasn't disabled before. 708 */ 709 if ((!sigma_delta->rdy_gpiod || gpiod_get_value(sigma_delta->rdy_gpiod)) && 710 ad_sd_disable_irq(sigma_delta)) { 711 complete(&sigma_delta->completion); 712 if (sigma_delta->trig) 713 iio_trigger_poll(sigma_delta->trig); 714 715 return IRQ_HANDLED; 716 } 717 718 return IRQ_NONE; 719 } 720 721 /** 722 * ad_sd_validate_trigger() - validate_trigger callback for ad_sigma_delta devices 723 * @indio_dev: The IIO device 724 * @trig: The new trigger 725 * 726 * Returns: 0 if the 'trig' matches the trigger registered by the ad_sigma_delta 727 * device, -EINVAL otherwise. 728 */ 729 int ad_sd_validate_trigger(struct iio_dev *indio_dev, struct iio_trigger *trig) 730 { 731 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 732 733 if (sigma_delta->trig != trig) 734 return -EINVAL; 735 736 return 0; 737 } 738 EXPORT_SYMBOL_NS_GPL(ad_sd_validate_trigger, "IIO_AD_SIGMA_DELTA"); 739 740 static int devm_ad_sd_probe_trigger(struct device *dev, struct iio_dev *indio_dev) 741 { 742 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 743 unsigned long irq_flags = irq_get_trigger_type(sigma_delta->irq_line); 744 int ret; 745 746 init_completion(&sigma_delta->completion); 747 748 sigma_delta->irq_dis = true; 749 750 /* the IRQ core clears IRQ_DISABLE_UNLAZY flag when freeing an IRQ */ 751 irq_set_status_flags(sigma_delta->irq_line, IRQ_DISABLE_UNLAZY); 752 753 /* Allow overwriting the flags from firmware */ 754 if (!irq_flags) 755 irq_flags = sigma_delta->info->irq_flags; 756 757 ret = devm_request_irq(dev, sigma_delta->irq_line, 758 ad_sd_data_rdy_trig_poll, 759 irq_flags | IRQF_NO_AUTOEN, 760 indio_dev->name, 761 sigma_delta); 762 if (ret) 763 return ret; 764 765 if (ad_sigma_delta_has_spi_offload(sigma_delta)) { 766 sigma_delta->offload_trigger = 767 devm_spi_offload_trigger_get(dev, sigma_delta->offload, 768 SPI_OFFLOAD_TRIGGER_DATA_READY); 769 if (IS_ERR(sigma_delta->offload_trigger)) 770 return dev_err_probe(dev, PTR_ERR(sigma_delta->offload_trigger), 771 "Failed to get SPI offload trigger\n"); 772 } else { 773 if (dev != &sigma_delta->spi->dev) 774 return dev_err_probe(dev, -EFAULT, 775 "Trigger parent should be '%s', got '%s'\n", 776 dev_name(dev), dev_name(&sigma_delta->spi->dev)); 777 778 sigma_delta->trig = devm_iio_trigger_alloc(dev, "%s-dev%d", 779 indio_dev->name, iio_device_id(indio_dev)); 780 if (!sigma_delta->trig) 781 return -ENOMEM; 782 783 iio_trigger_set_drvdata(sigma_delta->trig, sigma_delta); 784 785 ret = devm_iio_trigger_register(dev, sigma_delta->trig); 786 if (ret) 787 return ret; 788 789 /* select default trigger */ 790 indio_dev->trig = iio_trigger_get(sigma_delta->trig); 791 } 792 793 return 0; 794 } 795 796 /** 797 * devm_ad_sd_setup_buffer_and_trigger() - Device-managed buffer & trigger setup 798 * @dev: Device object to which to bind the life-time of the resources attached 799 * @indio_dev: The IIO device 800 */ 801 int devm_ad_sd_setup_buffer_and_trigger(struct device *dev, struct iio_dev *indio_dev) 802 { 803 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 804 int ret; 805 806 sigma_delta->slots = devm_kcalloc(dev, sigma_delta->num_slots, 807 sizeof(*sigma_delta->slots), GFP_KERNEL); 808 if (!sigma_delta->slots) 809 return -ENOMEM; 810 811 if (ad_sigma_delta_has_spi_offload(sigma_delta)) { 812 struct dma_chan *rx_dma; 813 814 rx_dma = devm_spi_offload_rx_stream_request_dma_chan(dev, 815 sigma_delta->offload); 816 if (IS_ERR(rx_dma)) 817 return dev_err_probe(dev, PTR_ERR(rx_dma), 818 "Failed to get RX DMA channel\n"); 819 820 ret = devm_iio_dmaengine_buffer_setup_with_handle(dev, indio_dev, 821 rx_dma, IIO_BUFFER_DIRECTION_IN); 822 if (ret) 823 return dev_err_probe(dev, ret, "Cannot setup DMA buffer\n"); 824 825 indio_dev->setup_ops = &ad_sd_buffer_setup_ops; 826 } else { 827 ret = devm_iio_triggered_buffer_setup(dev, indio_dev, 828 &iio_pollfunc_store_time, 829 &ad_sd_trigger_handler, 830 &ad_sd_buffer_setup_ops); 831 if (ret) 832 return ret; 833 } 834 835 return devm_ad_sd_probe_trigger(dev, indio_dev); 836 } 837 EXPORT_SYMBOL_NS_GPL(devm_ad_sd_setup_buffer_and_trigger, "IIO_AD_SIGMA_DELTA"); 838 839 /** 840 * ad_sd_init() - Initializes a ad_sigma_delta struct 841 * @sigma_delta: The ad_sigma_delta device 842 * @indio_dev: The IIO device which the Sigma Delta device is used for 843 * @spi: The SPI device for the ad_sigma_delta device 844 * @info: Device specific callbacks and options 845 * 846 * This function needs to be called before any other operations are performed on 847 * the ad_sigma_delta struct. 848 */ 849 int ad_sd_init(struct ad_sigma_delta *sigma_delta, struct iio_dev *indio_dev, 850 struct spi_device *spi, const struct ad_sigma_delta_info *info) 851 { 852 sigma_delta->spi = spi; 853 sigma_delta->info = info; 854 855 /* If the field is unset in ad_sigma_delta_info, assume there can only be 1 slot. */ 856 if (!info->num_slots) 857 sigma_delta->num_slots = 1; 858 else 859 sigma_delta->num_slots = info->num_slots; 860 861 if (sigma_delta->num_slots > 1) { 862 if (!indio_dev->info->update_scan_mode) { 863 dev_err(&spi->dev, "iio_dev lacks update_scan_mode().\n"); 864 return -EINVAL; 865 } 866 867 if (!info->disable_all) { 868 dev_err(&spi->dev, "ad_sigma_delta_info lacks disable_all().\n"); 869 return -EINVAL; 870 } 871 } 872 873 spin_lock_init(&sigma_delta->irq_lock); 874 875 if (info->has_named_irqs) { 876 sigma_delta->irq_line = fwnode_irq_get_byname(dev_fwnode(&spi->dev), 877 "rdy"); 878 if (sigma_delta->irq_line < 0) 879 return dev_err_probe(&spi->dev, sigma_delta->irq_line, 880 "Interrupt 'rdy' is required\n"); 881 } else { 882 sigma_delta->irq_line = spi->irq; 883 } 884 885 sigma_delta->rdy_gpiod = devm_gpiod_get_optional(&spi->dev, "rdy", GPIOD_IN); 886 if (IS_ERR(sigma_delta->rdy_gpiod)) 887 return dev_err_probe(&spi->dev, PTR_ERR(sigma_delta->rdy_gpiod), 888 "Failed to find rdy gpio\n"); 889 890 if (sigma_delta->rdy_gpiod && !sigma_delta->irq_line) { 891 sigma_delta->irq_line = gpiod_to_irq(sigma_delta->rdy_gpiod); 892 if (sigma_delta->irq_line < 0) 893 return sigma_delta->irq_line; 894 } 895 896 if (info->supports_spi_offload) { 897 struct spi_offload_config offload_config = { 898 .capability_flags = SPI_OFFLOAD_CAP_TRIGGER | 899 SPI_OFFLOAD_CAP_RX_STREAM_DMA, 900 }; 901 int ret; 902 903 sigma_delta->offload = devm_spi_offload_get(&spi->dev, spi, 904 &offload_config); 905 ret = PTR_ERR_OR_ZERO(sigma_delta->offload); 906 if (ret && ret != -ENODEV) 907 return dev_err_probe(&spi->dev, ret, "Failed to get SPI offload\n"); 908 } 909 910 iio_device_set_drvdata(indio_dev, sigma_delta); 911 912 return 0; 913 } 914 EXPORT_SYMBOL_NS_GPL(ad_sd_init, "IIO_AD_SIGMA_DELTA"); 915 916 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); 917 MODULE_DESCRIPTION("Analog Devices Sigma-Delta ADCs"); 918 MODULE_LICENSE("GPL v2"); 919 MODULE_IMPORT_NS("IIO_DMAENGINE_BUFFER"); 920