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 /* 55 * Some variants use the lower two bits of the communications register 56 * to select the channel. 57 */ 58 sigma_delta->comm = comm & AD_SD_COMM_CHAN_MASK; 59 } 60 EXPORT_SYMBOL_NS_GPL(ad_sd_set_comm, "IIO_AD_SIGMA_DELTA"); 61 62 /** 63 * ad_sd_write_reg() - Write a register 64 * 65 * @sigma_delta: The sigma delta device 66 * @reg: Address of the register 67 * @size: Size of the register (0-3) 68 * @val: Value to write to the register 69 * 70 * Returns 0 on success, an error code otherwise. 71 **/ 72 int ad_sd_write_reg(struct ad_sigma_delta *sigma_delta, unsigned int reg, 73 unsigned int size, unsigned int val) 74 { 75 u8 *data = sigma_delta->tx_buf; 76 struct spi_transfer t = { 77 .tx_buf = data, 78 .len = size + 1, 79 .cs_change = sigma_delta->keep_cs_asserted, 80 }; 81 struct spi_message m; 82 int ret; 83 84 data[0] = (reg << sigma_delta->info->addr_shift) | sigma_delta->comm; 85 86 switch (size) { 87 case 3: 88 put_unaligned_be24(val, &data[1]); 89 break; 90 case 2: 91 put_unaligned_be16(val, &data[1]); 92 break; 93 case 1: 94 data[1] = val; 95 break; 96 case 0: 97 break; 98 default: 99 return -EINVAL; 100 } 101 102 spi_message_init(&m); 103 spi_message_add_tail(&t, &m); 104 105 if (sigma_delta->bus_locked) 106 ret = spi_sync_locked(sigma_delta->spi, &m); 107 else 108 ret = spi_sync(sigma_delta->spi, &m); 109 110 return ret; 111 } 112 EXPORT_SYMBOL_NS_GPL(ad_sd_write_reg, "IIO_AD_SIGMA_DELTA"); 113 114 static void ad_sd_set_read_reg_addr(struct ad_sigma_delta *sigma_delta, u8 reg, 115 u8 *data) 116 { 117 data[0] = reg << sigma_delta->info->addr_shift; 118 data[0] |= sigma_delta->info->read_mask; 119 data[0] |= sigma_delta->comm; 120 } 121 122 static int ad_sd_read_reg_raw(struct ad_sigma_delta *sigma_delta, 123 unsigned int reg, unsigned int size, u8 *val) 124 { 125 u8 *data = sigma_delta->tx_buf; 126 int ret; 127 struct spi_transfer t[] = { 128 { 129 .tx_buf = data, 130 .len = 1, 131 }, { 132 .rx_buf = val, 133 .len = size, 134 .cs_change = sigma_delta->keep_cs_asserted, 135 }, 136 }; 137 struct spi_message m; 138 139 spi_message_init(&m); 140 141 if (sigma_delta->info->has_registers) { 142 ad_sd_set_read_reg_addr(sigma_delta, reg, data); 143 spi_message_add_tail(&t[0], &m); 144 } 145 spi_message_add_tail(&t[1], &m); 146 147 if (sigma_delta->bus_locked) 148 ret = spi_sync_locked(sigma_delta->spi, &m); 149 else 150 ret = spi_sync(sigma_delta->spi, &m); 151 152 return ret; 153 } 154 155 /** 156 * ad_sd_read_reg() - Read a register 157 * 158 * @sigma_delta: The sigma delta device 159 * @reg: Address of the register 160 * @size: Size of the register (1-4) 161 * @val: Read value 162 * 163 * Returns 0 on success, an error code otherwise. 164 **/ 165 int ad_sd_read_reg(struct ad_sigma_delta *sigma_delta, 166 unsigned int reg, unsigned int size, unsigned int *val) 167 { 168 int ret; 169 170 ret = ad_sd_read_reg_raw(sigma_delta, reg, size, sigma_delta->rx_buf); 171 if (ret < 0) 172 goto out; 173 174 switch (size) { 175 case 4: 176 *val = get_unaligned_be32(sigma_delta->rx_buf); 177 break; 178 case 3: 179 *val = get_unaligned_be24(sigma_delta->rx_buf); 180 break; 181 case 2: 182 *val = get_unaligned_be16(sigma_delta->rx_buf); 183 break; 184 case 1: 185 *val = sigma_delta->rx_buf[0]; 186 break; 187 default: 188 ret = -EINVAL; 189 break; 190 } 191 192 out: 193 return ret; 194 } 195 EXPORT_SYMBOL_NS_GPL(ad_sd_read_reg, "IIO_AD_SIGMA_DELTA"); 196 197 /** 198 * ad_sd_reset() - Reset the serial interface 199 * 200 * @sigma_delta: The sigma delta device 201 * 202 * Returns 0 on success, an error code otherwise. 203 **/ 204 int ad_sd_reset(struct ad_sigma_delta *sigma_delta) 205 { 206 unsigned int reset_length = sigma_delta->info->num_resetclks; 207 unsigned int size; 208 u8 *buf; 209 int ret; 210 211 size = BITS_TO_BYTES(reset_length); 212 buf = kcalloc(size, sizeof(*buf), GFP_KERNEL); 213 if (!buf) 214 return -ENOMEM; 215 216 memset(buf, 0xff, size); 217 ret = spi_write(sigma_delta->spi, buf, size); 218 kfree(buf); 219 220 return ret; 221 } 222 EXPORT_SYMBOL_NS_GPL(ad_sd_reset, "IIO_AD_SIGMA_DELTA"); 223 224 static bool ad_sd_disable_irq(struct ad_sigma_delta *sigma_delta) 225 { 226 guard(spinlock_irqsave)(&sigma_delta->irq_lock); 227 228 /* It's already off, return false to indicate nothing was changed */ 229 if (sigma_delta->irq_dis) 230 return false; 231 232 sigma_delta->irq_dis = true; 233 disable_irq_nosync(sigma_delta->irq_line); 234 return true; 235 } 236 237 static void ad_sd_enable_irq(struct ad_sigma_delta *sigma_delta) 238 { 239 guard(spinlock_irqsave)(&sigma_delta->irq_lock); 240 241 sigma_delta->irq_dis = false; 242 enable_irq(sigma_delta->irq_line); 243 } 244 245 #define AD_SD_CLEAR_DATA_BUFLEN 9 246 247 /* Called with `sigma_delta->bus_locked == true` only. */ 248 static int ad_sigma_delta_clear_pending_event(struct ad_sigma_delta *sigma_delta) 249 { 250 bool pending_event; 251 unsigned int data_read_len = BITS_TO_BYTES(sigma_delta->info->num_resetclks); 252 u8 *data; 253 struct spi_transfer t[] = { 254 { 255 .len = 1, 256 }, { 257 .len = data_read_len, 258 } 259 }; 260 struct spi_message m; 261 int ret; 262 263 /* 264 * Read R̅D̅Y̅ pin (if possible) or status register to check if there is an 265 * old event. For devices with neither an RDY GPIO nor registers, 266 * ad_sd_read_reg() transmits no address byte and clocks raw MISO bytes, 267 * which is indistinguishable from reading conversion data and would 268 * partially consume a pending result. Skip the check for such devices. 269 * 270 * This is safe for all current registerless devices: ad7191 and ad7780 271 * (with powerdown GPIO) are reset between conversions by CS deassertion, 272 * so there is no stale result to drain; ad7780 (without powerdown GPIO) 273 * and max11205 are continuously-converting and cycle ~DRDY at the output 274 * data rate regardless of whether the previous result was read, so the 275 * next falling edge fires naturally. 276 * 277 * A future registerless device that holds ~DRDY asserted until data is 278 * read would be broken by this early return and would need either 279 * num_resetclks set or a rdy-gpio. 280 */ 281 if (sigma_delta->rdy_gpiod) { 282 pending_event = gpiod_get_value(sigma_delta->rdy_gpiod); 283 } else if (sigma_delta->info->has_registers) { 284 unsigned int status_reg; 285 286 ret = ad_sd_read_reg(sigma_delta, AD_SD_REG_STATUS, 1, &status_reg); 287 if (ret) 288 return ret; 289 290 pending_event = !(status_reg & AD_SD_REG_STATUS_RDY); 291 } else { 292 return 0; 293 } 294 295 if (!pending_event) 296 return 0; 297 298 /* 299 * With num_resetclks = 0, data_read_len is 0 and the drain sequence 300 * below would compute memset(data + 2, 0xff, 0 - 1), underflowing to 301 * SIZE_MAX and corrupting the heap. There is no safe way to drain the 302 * stale result without knowing the data register size; it will be 303 * consumed by the first ad_sd_read_reg() call in 304 * ad_sigma_delta_single_conversion(). 305 */ 306 if (!data_read_len) 307 return 0; 308 309 /* 310 * In general the size of the data register is unknown. It varies from 311 * device to device, might be one byte longer if CONTROL.DATA_STATUS is 312 * set and even varies on some devices depending on which input is 313 * selected. So send one byte to start reading the data register and 314 * then just clock for some bytes with DIN (aka MOSI) high to not 315 * confuse the register access state machine after the data register was 316 * completely read. Note however that the sequence length must be 317 * shorter than the reset procedure. 318 */ 319 320 data = kzalloc(data_read_len + 1, GFP_KERNEL); 321 if (!data) 322 return -ENOMEM; 323 324 spi_message_init(&m); 325 if (sigma_delta->info->has_registers) { 326 unsigned int data_reg = sigma_delta->info->data_reg ?: AD_SD_REG_DATA; 327 328 ad_sd_set_read_reg_addr(sigma_delta, data_reg, data); 329 t[0].tx_buf = data; 330 spi_message_add_tail(&t[0], &m); 331 } 332 333 /* 334 * The first transferred byte is part of the real data register, 335 * so this doesn't need to be 0xff. In the remaining 336 * `data_read_len - 1` bytes are less than $num_resetclks ones. 337 */ 338 t[1].tx_buf = data + 1; 339 data[1] = 0x00; 340 memset(data + 2, 0xff, data_read_len - 1); 341 spi_message_add_tail(&t[1], &m); 342 343 ret = spi_sync_locked(sigma_delta->spi, &m); 344 345 kfree(data); 346 347 return ret; 348 } 349 350 int ad_sd_calibrate(struct ad_sigma_delta *sigma_delta, 351 unsigned int mode, unsigned int channel) 352 { 353 int ret; 354 unsigned long time_left; 355 356 ret = ad_sigma_delta_set_channel(sigma_delta, channel); 357 if (ret) 358 return ret; 359 360 spi_bus_lock(sigma_delta->spi->controller); 361 sigma_delta->bus_locked = true; 362 sigma_delta->keep_cs_asserted = true; 363 reinit_completion(&sigma_delta->completion); 364 365 ret = ad_sigma_delta_clear_pending_event(sigma_delta); 366 if (ret) 367 goto out; 368 369 ret = ad_sigma_delta_set_mode(sigma_delta, mode); 370 if (ret < 0) 371 goto out; 372 373 ad_sd_enable_irq(sigma_delta); 374 time_left = wait_for_completion_timeout(&sigma_delta->completion, 2 * HZ); 375 if (time_left == 0) { 376 ad_sd_disable_irq(sigma_delta); 377 ret = -EIO; 378 } else { 379 ret = 0; 380 } 381 out: 382 sigma_delta->keep_cs_asserted = false; 383 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE); 384 ad_sigma_delta_disable_one(sigma_delta, channel); 385 sigma_delta->bus_locked = false; 386 spi_bus_unlock(sigma_delta->spi->controller); 387 388 return ret; 389 } 390 EXPORT_SYMBOL_NS_GPL(ad_sd_calibrate, "IIO_AD_SIGMA_DELTA"); 391 392 /** 393 * ad_sd_calibrate_all() - Performs channel calibration 394 * @sigma_delta: The sigma delta device 395 * @cb: Array of channels and calibration type to perform 396 * @n: Number of items in cb 397 * 398 * Returns 0 on success, an error code otherwise. 399 **/ 400 int ad_sd_calibrate_all(struct ad_sigma_delta *sigma_delta, 401 const struct ad_sd_calib_data *cb, unsigned int n) 402 { 403 unsigned int i; 404 int ret; 405 406 for (i = 0; i < n; i++) { 407 ret = ad_sd_calibrate(sigma_delta, cb[i].mode, cb[i].channel); 408 if (ret) 409 return ret; 410 } 411 412 return 0; 413 } 414 EXPORT_SYMBOL_NS_GPL(ad_sd_calibrate_all, "IIO_AD_SIGMA_DELTA"); 415 416 /** 417 * ad_sigma_delta_single_conversion() - Performs a single data conversion 418 * @indio_dev: The IIO device 419 * @chan: The conversion is done for this channel 420 * @val: Pointer to the location where to store the read value 421 * 422 * Returns: 0 on success, an error value otherwise. 423 */ 424 int ad_sigma_delta_single_conversion(struct iio_dev *indio_dev, 425 const struct iio_chan_spec *chan, int *val) 426 { 427 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 428 unsigned int sample, raw_sample; 429 unsigned int data_reg; 430 int ret = 0; 431 432 if (!iio_device_claim_direct(indio_dev)) 433 return -EBUSY; 434 435 ret = ad_sigma_delta_set_channel(sigma_delta, chan->address); 436 if (ret) 437 goto out_release; 438 439 spi_bus_lock(sigma_delta->spi->controller); 440 sigma_delta->bus_locked = true; 441 sigma_delta->keep_cs_asserted = true; 442 reinit_completion(&sigma_delta->completion); 443 444 ret = ad_sigma_delta_clear_pending_event(sigma_delta); 445 if (ret) 446 goto out_unlock; 447 448 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_SINGLE); 449 450 ad_sd_enable_irq(sigma_delta); 451 ret = wait_for_completion_interruptible_timeout( 452 &sigma_delta->completion, HZ); 453 454 if (ret == 0) 455 ret = -EIO; 456 if (ret < 0) 457 goto out; 458 459 if (sigma_delta->info->data_reg != 0) 460 data_reg = sigma_delta->info->data_reg; 461 else 462 data_reg = AD_SD_REG_DATA; 463 464 ret = ad_sd_read_reg(sigma_delta, data_reg, 465 BITS_TO_BYTES(chan->scan_type.realbits + chan->scan_type.shift), 466 &raw_sample); 467 468 out: 469 ad_sd_disable_irq(sigma_delta); 470 471 out_unlock: 472 sigma_delta->keep_cs_asserted = false; 473 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE); 474 ad_sigma_delta_disable_one(sigma_delta, chan->address); 475 sigma_delta->bus_locked = false; 476 spi_bus_unlock(sigma_delta->spi->controller); 477 out_release: 478 iio_device_release_direct(indio_dev); 479 480 if (ret) 481 return ret; 482 483 sample = raw_sample >> chan->scan_type.shift; 484 sample &= (1 << chan->scan_type.realbits) - 1; 485 *val = sample; 486 487 ret = ad_sigma_delta_postprocess_sample(sigma_delta, raw_sample); 488 if (ret) 489 return ret; 490 491 return IIO_VAL_INT; 492 } 493 EXPORT_SYMBOL_NS_GPL(ad_sigma_delta_single_conversion, "IIO_AD_SIGMA_DELTA"); 494 495 static int ad_sd_buffer_postenable(struct iio_dev *indio_dev) 496 { 497 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 498 const struct iio_scan_type *scan_type = &indio_dev->channels[0].scan_type; 499 struct spi_transfer *xfer = sigma_delta->sample_xfer; 500 unsigned int i, slot, channel; 501 u8 *samples_buf; 502 int ret; 503 504 if (sigma_delta->num_slots == 1) { 505 channel = find_first_bit(indio_dev->active_scan_mask, 506 iio_get_masklength(indio_dev)); 507 ret = ad_sigma_delta_set_channel(sigma_delta, 508 indio_dev->channels[channel].address); 509 if (ret) 510 return ret; 511 slot = 1; 512 } else { 513 /* 514 * At this point update_scan_mode already enabled the required channels. 515 * For sigma-delta sequencer drivers with multiple slots, an update_scan_mode 516 * implementation is mandatory. 517 */ 518 slot = 0; 519 iio_for_each_active_channel(indio_dev, i) { 520 sigma_delta->slots[slot] = indio_dev->channels[i].address; 521 slot++; 522 } 523 } 524 525 sigma_delta->active_slots = slot; 526 sigma_delta->current_slot = 0; 527 528 if (ad_sigma_delta_has_spi_offload(sigma_delta)) { 529 xfer[1].offload_flags = SPI_OFFLOAD_XFER_RX_STREAM; 530 xfer[1].bits_per_word = scan_type->realbits; 531 xfer[1].len = spi_bpw_to_bytes(scan_type->realbits); 532 } else { 533 unsigned int samples_buf_size, scan_size; 534 535 if (sigma_delta->active_slots > 1) { 536 ret = ad_sigma_delta_append_status(sigma_delta, true); 537 if (ret) 538 return ret; 539 } 540 541 samples_buf_size = 542 ALIGN(slot * BITS_TO_BYTES(scan_type->storagebits), 543 sizeof(s64)); 544 samples_buf_size += sizeof(s64); 545 samples_buf = devm_krealloc(&sigma_delta->spi->dev, 546 sigma_delta->samples_buf, 547 samples_buf_size, GFP_KERNEL); 548 if (!samples_buf) 549 return -ENOMEM; 550 551 sigma_delta->samples_buf = samples_buf; 552 scan_size = BITS_TO_BYTES(scan_type->realbits + scan_type->shift); 553 /* For 24-bit data, there is an extra byte of padding. */ 554 xfer[1].rx_buf = &sigma_delta->rx_buf[scan_size == 3 ? 1 : 0]; 555 xfer[1].len = scan_size + (sigma_delta->status_appended ? 1 : 0); 556 } 557 xfer[1].cs_change = 1; 558 559 if (sigma_delta->info->has_registers) { 560 xfer[0].tx_buf = &sigma_delta->sample_addr; 561 xfer[0].len = 1; 562 563 ad_sd_set_read_reg_addr(sigma_delta, 564 sigma_delta->info->data_reg ?: AD_SD_REG_DATA, 565 &sigma_delta->sample_addr); 566 spi_message_init_with_transfers(&sigma_delta->sample_msg, xfer, 2); 567 } else { 568 spi_message_init_with_transfers(&sigma_delta->sample_msg, 569 &xfer[1], 1); 570 } 571 572 sigma_delta->sample_msg.offload = sigma_delta->offload; 573 574 ret = spi_optimize_message(sigma_delta->spi, &sigma_delta->sample_msg); 575 if (ret) 576 return ret; 577 578 spi_bus_lock(sigma_delta->spi->controller); 579 sigma_delta->bus_locked = true; 580 sigma_delta->keep_cs_asserted = true; 581 582 ret = ad_sigma_delta_clear_pending_event(sigma_delta); 583 if (ret) 584 goto err_unlock; 585 586 ret = ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_CONTINUOUS); 587 if (ret) 588 goto err_unlock; 589 590 if (ad_sigma_delta_has_spi_offload(sigma_delta)) { 591 struct spi_offload_trigger_config config = { 592 .type = SPI_OFFLOAD_TRIGGER_DATA_READY, 593 }; 594 595 ret = spi_offload_trigger_enable(sigma_delta->offload, 596 sigma_delta->offload_trigger, 597 &config); 598 if (ret) 599 goto err_unlock; 600 } else { 601 ad_sd_enable_irq(sigma_delta); 602 } 603 604 return 0; 605 606 err_unlock: 607 sigma_delta->keep_cs_asserted = false; 608 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE); 609 sigma_delta->bus_locked = false; 610 spi_bus_unlock(sigma_delta->spi->controller); 611 spi_unoptimize_message(&sigma_delta->sample_msg); 612 613 return ret; 614 } 615 616 static int ad_sd_buffer_predisable(struct iio_dev *indio_dev) 617 { 618 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 619 620 if (ad_sigma_delta_has_spi_offload(sigma_delta)) { 621 spi_offload_trigger_disable(sigma_delta->offload, 622 sigma_delta->offload_trigger); 623 } else { 624 reinit_completion(&sigma_delta->completion); 625 wait_for_completion_timeout(&sigma_delta->completion, HZ); 626 627 ad_sd_disable_irq(sigma_delta); 628 } 629 630 sigma_delta->keep_cs_asserted = false; 631 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE); 632 633 if (sigma_delta->status_appended) 634 ad_sigma_delta_append_status(sigma_delta, false); 635 636 ad_sigma_delta_disable_all(sigma_delta); 637 sigma_delta->bus_locked = false; 638 spi_bus_unlock(sigma_delta->spi->controller); 639 spi_unoptimize_message(&sigma_delta->sample_msg); 640 641 return 0; 642 } 643 644 static irqreturn_t ad_sd_trigger_handler(int irq, void *p) 645 { 646 struct iio_poll_func *pf = p; 647 struct iio_dev *indio_dev = pf->indio_dev; 648 const struct iio_scan_type *scan_type = &indio_dev->channels[0].scan_type; 649 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 650 u8 *data = sigma_delta->rx_buf; 651 unsigned int sample_size; 652 unsigned int sample_pos; 653 unsigned int status_pos; 654 unsigned int reg_size; 655 int ret; 656 657 reg_size = BITS_TO_BYTES(scan_type->realbits + scan_type->shift); 658 /* For 24-bit data, there is an extra byte of padding. */ 659 status_pos = reg_size + (reg_size == 3 ? 1 : 0); 660 661 ret = spi_sync_locked(sigma_delta->spi, &sigma_delta->sample_msg); 662 if (ret) 663 goto irq_handled; 664 665 /* 666 * For devices sampling only one channel at 667 * once, there is no need for sample number tracking. 668 */ 669 if (sigma_delta->active_slots == 1) { 670 iio_push_to_buffers_with_timestamp(indio_dev, data, pf->timestamp); 671 goto irq_handled; 672 } 673 674 if (sigma_delta->status_appended) { 675 u8 converted_channel; 676 677 converted_channel = data[status_pos] & sigma_delta->info->status_ch_mask; 678 if (converted_channel != sigma_delta->slots[sigma_delta->current_slot]) { 679 /* 680 * Desync occurred during continuous sampling of multiple channels. 681 * Drop this incomplete sample and start from first channel again. 682 */ 683 684 sigma_delta->current_slot = 0; 685 goto irq_handled; 686 } 687 } 688 689 sample_size = BITS_TO_BYTES(scan_type->storagebits); 690 sample_pos = sample_size * sigma_delta->current_slot; 691 memcpy(&sigma_delta->samples_buf[sample_pos], data, sample_size); 692 sigma_delta->current_slot++; 693 694 if (sigma_delta->current_slot == sigma_delta->active_slots) { 695 sigma_delta->current_slot = 0; 696 iio_push_to_buffers_with_timestamp(indio_dev, sigma_delta->samples_buf, 697 pf->timestamp); 698 } 699 700 irq_handled: 701 iio_trigger_notify_done(indio_dev->trig); 702 ad_sd_enable_irq(sigma_delta); 703 704 return IRQ_HANDLED; 705 } 706 707 static bool ad_sd_validate_scan_mask(struct iio_dev *indio_dev, const unsigned long *mask) 708 { 709 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 710 711 return bitmap_weight(mask, iio_get_masklength(indio_dev)) <= sigma_delta->num_slots; 712 } 713 714 static const struct iio_buffer_setup_ops ad_sd_buffer_setup_ops = { 715 .postenable = &ad_sd_buffer_postenable, 716 .predisable = &ad_sd_buffer_predisable, 717 .validate_scan_mask = &ad_sd_validate_scan_mask, 718 }; 719 720 static irqreturn_t ad_sd_data_rdy_trig_poll(int irq, void *private) 721 { 722 struct ad_sigma_delta *sigma_delta = private; 723 724 /* 725 * AD7124 and a few others use the same physical line for interrupt 726 * reporting (R̅D̅Y̅) and MISO. 727 * As MISO toggles when reading a register, this likely results in a 728 * pending interrupt. This has two consequences: a) The irq might 729 * trigger immediately after it's enabled even though the conversion 730 * isn't done yet; and b) checking the STATUS register's R̅D̅Y̅ flag is 731 * off-limits as reading that would trigger another irq event. 732 * 733 * So read the MOSI line as GPIO (if available) and only trigger the irq 734 * if the line is active. Without such a GPIO assume this is a valid 735 * interrupt. 736 * 737 * Also as disable_irq_nosync() is used to disable the irq, only act if 738 * the irq wasn't disabled before. 739 */ 740 if ((!sigma_delta->rdy_gpiod || gpiod_get_value(sigma_delta->rdy_gpiod)) && 741 ad_sd_disable_irq(sigma_delta)) { 742 complete(&sigma_delta->completion); 743 if (sigma_delta->trig) 744 iio_trigger_poll(sigma_delta->trig); 745 746 return IRQ_HANDLED; 747 } 748 749 return IRQ_NONE; 750 } 751 752 /** 753 * ad_sd_validate_trigger() - validate_trigger callback for ad_sigma_delta devices 754 * @indio_dev: The IIO device 755 * @trig: The new trigger 756 * 757 * Returns: 0 if the 'trig' matches the trigger registered by the ad_sigma_delta 758 * device, -EINVAL otherwise. 759 */ 760 int ad_sd_validate_trigger(struct iio_dev *indio_dev, struct iio_trigger *trig) 761 { 762 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 763 764 if (sigma_delta->trig != trig) 765 return -EINVAL; 766 767 return 0; 768 } 769 EXPORT_SYMBOL_NS_GPL(ad_sd_validate_trigger, "IIO_AD_SIGMA_DELTA"); 770 771 static int devm_ad_sd_probe_trigger(struct device *dev, struct iio_dev *indio_dev) 772 { 773 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 774 unsigned long irq_flags = irq_get_trigger_type(sigma_delta->irq_line); 775 int ret; 776 777 init_completion(&sigma_delta->completion); 778 779 sigma_delta->irq_dis = true; 780 781 /* the IRQ core clears IRQ_DISABLE_UNLAZY flag when freeing an IRQ */ 782 irq_set_status_flags(sigma_delta->irq_line, IRQ_DISABLE_UNLAZY); 783 784 /* Allow overwriting the flags from firmware */ 785 if (!irq_flags) 786 irq_flags = sigma_delta->info->irq_flags; 787 788 ret = devm_request_irq(dev, sigma_delta->irq_line, 789 ad_sd_data_rdy_trig_poll, 790 irq_flags | IRQF_NO_AUTOEN, 791 indio_dev->name, 792 sigma_delta); 793 if (ret) 794 return ret; 795 796 if (ad_sigma_delta_has_spi_offload(sigma_delta)) { 797 sigma_delta->offload_trigger = 798 devm_spi_offload_trigger_get(dev, sigma_delta->offload, 799 SPI_OFFLOAD_TRIGGER_DATA_READY); 800 if (IS_ERR(sigma_delta->offload_trigger)) 801 return dev_err_probe(dev, PTR_ERR(sigma_delta->offload_trigger), 802 "Failed to get SPI offload trigger\n"); 803 } else { 804 if (dev != &sigma_delta->spi->dev) 805 return dev_err_probe(dev, -EFAULT, 806 "Trigger parent should be '%s', got '%s'\n", 807 dev_name(dev), dev_name(&sigma_delta->spi->dev)); 808 809 sigma_delta->trig = devm_iio_trigger_alloc(dev, "%s-dev%d", 810 indio_dev->name, iio_device_id(indio_dev)); 811 if (!sigma_delta->trig) 812 return -ENOMEM; 813 814 iio_trigger_set_drvdata(sigma_delta->trig, sigma_delta); 815 816 ret = devm_iio_trigger_register(dev, sigma_delta->trig); 817 if (ret) 818 return ret; 819 820 /* select default trigger */ 821 indio_dev->trig = iio_trigger_get(sigma_delta->trig); 822 } 823 824 return 0; 825 } 826 827 /** 828 * devm_ad_sd_setup_buffer_and_trigger() - Device-managed buffer & trigger setup 829 * @dev: Device object to which to bind the life-time of the resources attached 830 * @indio_dev: The IIO device 831 */ 832 int devm_ad_sd_setup_buffer_and_trigger(struct device *dev, struct iio_dev *indio_dev) 833 { 834 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 835 int ret; 836 837 sigma_delta->slots = devm_kcalloc(dev, sigma_delta->num_slots, 838 sizeof(*sigma_delta->slots), GFP_KERNEL); 839 if (!sigma_delta->slots) 840 return -ENOMEM; 841 842 if (ad_sigma_delta_has_spi_offload(sigma_delta)) { 843 struct dma_chan *rx_dma; 844 845 rx_dma = devm_spi_offload_rx_stream_request_dma_chan(dev, 846 sigma_delta->offload); 847 if (IS_ERR(rx_dma)) 848 return dev_err_probe(dev, PTR_ERR(rx_dma), 849 "Failed to get RX DMA channel\n"); 850 851 ret = devm_iio_dmaengine_buffer_setup_with_handle(dev, indio_dev, 852 rx_dma, IIO_BUFFER_DIRECTION_IN); 853 if (ret) 854 return dev_err_probe(dev, ret, "Cannot setup DMA buffer\n"); 855 856 indio_dev->setup_ops = &ad_sd_buffer_setup_ops; 857 } else { 858 ret = devm_iio_triggered_buffer_setup(dev, indio_dev, 859 &iio_pollfunc_store_time, 860 &ad_sd_trigger_handler, 861 &ad_sd_buffer_setup_ops); 862 if (ret) 863 return ret; 864 } 865 866 return devm_ad_sd_probe_trigger(dev, indio_dev); 867 } 868 EXPORT_SYMBOL_NS_GPL(devm_ad_sd_setup_buffer_and_trigger, "IIO_AD_SIGMA_DELTA"); 869 870 /** 871 * ad_sd_init() - Initializes a ad_sigma_delta struct 872 * @sigma_delta: The ad_sigma_delta device 873 * @indio_dev: The IIO device which the Sigma Delta device is used for 874 * @spi: The SPI device for the ad_sigma_delta device 875 * @info: Device specific callbacks and options 876 * 877 * This function needs to be called before any other operations are performed on 878 * the ad_sigma_delta struct. 879 */ 880 int ad_sd_init(struct ad_sigma_delta *sigma_delta, struct iio_dev *indio_dev, 881 struct spi_device *spi, const struct ad_sigma_delta_info *info) 882 { 883 sigma_delta->spi = spi; 884 sigma_delta->info = info; 885 886 /* If the field is unset in ad_sigma_delta_info, assume there can only be 1 slot. */ 887 if (!info->num_slots) 888 sigma_delta->num_slots = 1; 889 else 890 sigma_delta->num_slots = info->num_slots; 891 892 if (sigma_delta->num_slots > 1) { 893 if (!indio_dev->info->update_scan_mode) { 894 dev_err(&spi->dev, "iio_dev lacks update_scan_mode().\n"); 895 return -EINVAL; 896 } 897 898 if (!info->disable_all) { 899 dev_err(&spi->dev, "ad_sigma_delta_info lacks disable_all().\n"); 900 return -EINVAL; 901 } 902 } 903 904 spin_lock_init(&sigma_delta->irq_lock); 905 906 if (info->has_named_irqs) { 907 sigma_delta->irq_line = fwnode_irq_get_byname(dev_fwnode(&spi->dev), 908 "rdy"); 909 if (sigma_delta->irq_line < 0) 910 return dev_err_probe(&spi->dev, sigma_delta->irq_line, 911 "Interrupt 'rdy' is required\n"); 912 } else { 913 sigma_delta->irq_line = spi->irq; 914 } 915 916 sigma_delta->rdy_gpiod = devm_gpiod_get_optional(&spi->dev, "rdy", GPIOD_IN); 917 if (IS_ERR(sigma_delta->rdy_gpiod)) 918 return dev_err_probe(&spi->dev, PTR_ERR(sigma_delta->rdy_gpiod), 919 "Failed to find rdy gpio\n"); 920 921 if (sigma_delta->rdy_gpiod && !sigma_delta->irq_line) { 922 sigma_delta->irq_line = gpiod_to_irq(sigma_delta->rdy_gpiod); 923 if (sigma_delta->irq_line < 0) 924 return sigma_delta->irq_line; 925 } 926 927 if (info->supports_spi_offload) { 928 struct spi_offload_config offload_config = { 929 .capability_flags = SPI_OFFLOAD_CAP_TRIGGER | 930 SPI_OFFLOAD_CAP_RX_STREAM_DMA, 931 }; 932 int ret; 933 934 sigma_delta->offload = devm_spi_offload_get(&spi->dev, spi, 935 &offload_config); 936 ret = PTR_ERR_OR_ZERO(sigma_delta->offload); 937 if (ret && ret != -ENODEV) 938 return dev_err_probe(&spi->dev, ret, "Failed to get SPI offload\n"); 939 } 940 941 iio_device_set_drvdata(indio_dev, sigma_delta); 942 943 return 0; 944 } 945 EXPORT_SYMBOL_NS_GPL(ad_sd_init, "IIO_AD_SIGMA_DELTA"); 946 947 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); 948 MODULE_DESCRIPTION("Analog Devices Sigma-Delta ADCs"); 949 MODULE_LICENSE("GPL v2"); 950 MODULE_IMPORT_NS("IIO_DMAENGINE_BUFFER"); 951