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/interrupt.h> 10 #include <linux/device.h> 11 #include <linux/kernel.h> 12 #include <linux/slab.h> 13 #include <linux/spi/spi.h> 14 #include <linux/err.h> 15 #include <linux/module.h> 16 17 #include <linux/iio/iio.h> 18 #include <linux/iio/sysfs.h> 19 #include <linux/iio/buffer.h> 20 #include <linux/iio/trigger.h> 21 #include <linux/iio/trigger_consumer.h> 22 #include <linux/iio/triggered_buffer.h> 23 #include <linux/iio/adc/ad_sigma_delta.h> 24 25 #include <asm/unaligned.h> 26 27 28 #define AD_SD_COMM_CHAN_MASK 0x3 29 30 #define AD_SD_REG_COMM 0x00 31 #define AD_SD_REG_DATA 0x03 32 33 /** 34 * ad_sd_set_comm() - Set communications register 35 * 36 * @sigma_delta: The sigma delta device 37 * @comm: New value for the communications register 38 */ 39 void ad_sd_set_comm(struct ad_sigma_delta *sigma_delta, uint8_t comm) 40 { 41 /* Some variants use the lower two bits of the communications register 42 * to select the channel */ 43 sigma_delta->comm = comm & AD_SD_COMM_CHAN_MASK; 44 } 45 EXPORT_SYMBOL_GPL(ad_sd_set_comm); 46 47 /** 48 * ad_sd_write_reg() - Write a register 49 * 50 * @sigma_delta: The sigma delta device 51 * @reg: Address of the register 52 * @size: Size of the register (0-3) 53 * @val: Value to write to the register 54 * 55 * Returns 0 on success, an error code otherwise. 56 **/ 57 int ad_sd_write_reg(struct ad_sigma_delta *sigma_delta, unsigned int reg, 58 unsigned int size, unsigned int val) 59 { 60 uint8_t *data = sigma_delta->data; 61 struct spi_transfer t = { 62 .tx_buf = data, 63 .len = size + 1, 64 .cs_change = sigma_delta->keep_cs_asserted, 65 }; 66 struct spi_message m; 67 int ret; 68 69 data[0] = (reg << sigma_delta->info->addr_shift) | sigma_delta->comm; 70 71 switch (size) { 72 case 3: 73 data[1] = val >> 16; 74 data[2] = val >> 8; 75 data[3] = val; 76 break; 77 case 2: 78 put_unaligned_be16(val, &data[1]); 79 break; 80 case 1: 81 data[1] = val; 82 break; 83 case 0: 84 break; 85 default: 86 return -EINVAL; 87 } 88 89 spi_message_init(&m); 90 spi_message_add_tail(&t, &m); 91 92 if (sigma_delta->bus_locked) 93 ret = spi_sync_locked(sigma_delta->spi, &m); 94 else 95 ret = spi_sync(sigma_delta->spi, &m); 96 97 return ret; 98 } 99 EXPORT_SYMBOL_GPL(ad_sd_write_reg); 100 101 static int ad_sd_read_reg_raw(struct ad_sigma_delta *sigma_delta, 102 unsigned int reg, unsigned int size, uint8_t *val) 103 { 104 uint8_t *data = sigma_delta->data; 105 int ret; 106 struct spi_transfer t[] = { 107 { 108 .tx_buf = data, 109 .len = 1, 110 }, { 111 .rx_buf = val, 112 .len = size, 113 .cs_change = sigma_delta->bus_locked, 114 }, 115 }; 116 struct spi_message m; 117 118 spi_message_init(&m); 119 120 if (sigma_delta->info->has_registers) { 121 data[0] = reg << sigma_delta->info->addr_shift; 122 data[0] |= sigma_delta->info->read_mask; 123 data[0] |= sigma_delta->comm; 124 spi_message_add_tail(&t[0], &m); 125 } 126 spi_message_add_tail(&t[1], &m); 127 128 if (sigma_delta->bus_locked) 129 ret = spi_sync_locked(sigma_delta->spi, &m); 130 else 131 ret = spi_sync(sigma_delta->spi, &m); 132 133 return ret; 134 } 135 136 /** 137 * ad_sd_read_reg() - Read a register 138 * 139 * @sigma_delta: The sigma delta device 140 * @reg: Address of the register 141 * @size: Size of the register (1-4) 142 * @val: Read value 143 * 144 * Returns 0 on success, an error code otherwise. 145 **/ 146 int ad_sd_read_reg(struct ad_sigma_delta *sigma_delta, 147 unsigned int reg, unsigned int size, unsigned int *val) 148 { 149 int ret; 150 151 ret = ad_sd_read_reg_raw(sigma_delta, reg, size, sigma_delta->data); 152 if (ret < 0) 153 goto out; 154 155 switch (size) { 156 case 4: 157 *val = get_unaligned_be32(sigma_delta->data); 158 break; 159 case 3: 160 *val = (sigma_delta->data[0] << 16) | 161 (sigma_delta->data[1] << 8) | 162 sigma_delta->data[2]; 163 break; 164 case 2: 165 *val = get_unaligned_be16(sigma_delta->data); 166 break; 167 case 1: 168 *val = sigma_delta->data[0]; 169 break; 170 default: 171 ret = -EINVAL; 172 break; 173 } 174 175 out: 176 return ret; 177 } 178 EXPORT_SYMBOL_GPL(ad_sd_read_reg); 179 180 /** 181 * ad_sd_reset() - Reset the serial interface 182 * 183 * @sigma_delta: The sigma delta device 184 * @reset_length: Number of SCLKs with DIN = 1 185 * 186 * Returns 0 on success, an error code otherwise. 187 **/ 188 int ad_sd_reset(struct ad_sigma_delta *sigma_delta, 189 unsigned int reset_length) 190 { 191 uint8_t *buf; 192 unsigned int size; 193 int ret; 194 195 size = DIV_ROUND_UP(reset_length, 8); 196 buf = kcalloc(size, sizeof(*buf), GFP_KERNEL); 197 if (!buf) 198 return -ENOMEM; 199 200 memset(buf, 0xff, size); 201 ret = spi_write(sigma_delta->spi, buf, size); 202 kfree(buf); 203 204 return ret; 205 } 206 EXPORT_SYMBOL_GPL(ad_sd_reset); 207 208 static int ad_sd_calibrate(struct ad_sigma_delta *sigma_delta, 209 unsigned int mode, unsigned int channel) 210 { 211 int ret; 212 unsigned long timeout; 213 214 ret = ad_sigma_delta_set_channel(sigma_delta, channel); 215 if (ret) 216 return ret; 217 218 spi_bus_lock(sigma_delta->spi->master); 219 sigma_delta->bus_locked = true; 220 sigma_delta->keep_cs_asserted = true; 221 reinit_completion(&sigma_delta->completion); 222 223 ret = ad_sigma_delta_set_mode(sigma_delta, mode); 224 if (ret < 0) 225 goto out; 226 227 sigma_delta->irq_dis = false; 228 enable_irq(sigma_delta->spi->irq); 229 timeout = wait_for_completion_timeout(&sigma_delta->completion, 2 * HZ); 230 if (timeout == 0) { 231 sigma_delta->irq_dis = true; 232 disable_irq_nosync(sigma_delta->spi->irq); 233 ret = -EIO; 234 } else { 235 ret = 0; 236 } 237 out: 238 sigma_delta->keep_cs_asserted = false; 239 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE); 240 sigma_delta->bus_locked = false; 241 spi_bus_unlock(sigma_delta->spi->master); 242 243 return ret; 244 } 245 246 /** 247 * ad_sd_calibrate_all() - Performs channel calibration 248 * @sigma_delta: The sigma delta device 249 * @cb: Array of channels and calibration type to perform 250 * @n: Number of items in cb 251 * 252 * Returns 0 on success, an error code otherwise. 253 **/ 254 int ad_sd_calibrate_all(struct ad_sigma_delta *sigma_delta, 255 const struct ad_sd_calib_data *cb, unsigned int n) 256 { 257 unsigned int i; 258 int ret; 259 260 for (i = 0; i < n; i++) { 261 ret = ad_sd_calibrate(sigma_delta, cb[i].mode, cb[i].channel); 262 if (ret) 263 return ret; 264 } 265 266 return 0; 267 } 268 EXPORT_SYMBOL_GPL(ad_sd_calibrate_all); 269 270 /** 271 * ad_sigma_delta_single_conversion() - Performs a single data conversion 272 * @indio_dev: The IIO device 273 * @chan: The conversion is done for this channel 274 * @val: Pointer to the location where to store the read value 275 * 276 * Returns: 0 on success, an error value otherwise. 277 */ 278 int ad_sigma_delta_single_conversion(struct iio_dev *indio_dev, 279 const struct iio_chan_spec *chan, int *val) 280 { 281 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 282 unsigned int sample, raw_sample; 283 unsigned int data_reg; 284 int ret = 0; 285 286 if (iio_buffer_enabled(indio_dev)) 287 return -EBUSY; 288 289 mutex_lock(&indio_dev->mlock); 290 ad_sigma_delta_set_channel(sigma_delta, chan->address); 291 292 spi_bus_lock(sigma_delta->spi->master); 293 sigma_delta->bus_locked = true; 294 sigma_delta->keep_cs_asserted = true; 295 reinit_completion(&sigma_delta->completion); 296 297 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_SINGLE); 298 299 sigma_delta->irq_dis = false; 300 enable_irq(sigma_delta->spi->irq); 301 ret = wait_for_completion_interruptible_timeout( 302 &sigma_delta->completion, HZ); 303 304 if (ret == 0) 305 ret = -EIO; 306 if (ret < 0) 307 goto out; 308 309 if (sigma_delta->info->data_reg != 0) 310 data_reg = sigma_delta->info->data_reg; 311 else 312 data_reg = AD_SD_REG_DATA; 313 314 ret = ad_sd_read_reg(sigma_delta, data_reg, 315 DIV_ROUND_UP(chan->scan_type.realbits + chan->scan_type.shift, 8), 316 &raw_sample); 317 318 out: 319 if (!sigma_delta->irq_dis) { 320 disable_irq_nosync(sigma_delta->spi->irq); 321 sigma_delta->irq_dis = true; 322 } 323 324 sigma_delta->keep_cs_asserted = false; 325 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE); 326 sigma_delta->bus_locked = false; 327 spi_bus_unlock(sigma_delta->spi->master); 328 mutex_unlock(&indio_dev->mlock); 329 330 if (ret) 331 return ret; 332 333 sample = raw_sample >> chan->scan_type.shift; 334 sample &= (1 << chan->scan_type.realbits) - 1; 335 *val = sample; 336 337 ret = ad_sigma_delta_postprocess_sample(sigma_delta, raw_sample); 338 if (ret) 339 return ret; 340 341 return IIO_VAL_INT; 342 } 343 EXPORT_SYMBOL_GPL(ad_sigma_delta_single_conversion); 344 345 static int ad_sd_buffer_postenable(struct iio_dev *indio_dev) 346 { 347 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 348 unsigned int channel; 349 int ret; 350 351 ret = iio_triggered_buffer_postenable(indio_dev); 352 if (ret < 0) 353 return ret; 354 355 channel = find_first_bit(indio_dev->active_scan_mask, 356 indio_dev->masklength); 357 ret = ad_sigma_delta_set_channel(sigma_delta, 358 indio_dev->channels[channel].address); 359 if (ret) 360 goto err_predisable; 361 362 spi_bus_lock(sigma_delta->spi->master); 363 sigma_delta->bus_locked = true; 364 sigma_delta->keep_cs_asserted = true; 365 366 ret = ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_CONTINUOUS); 367 if (ret) 368 goto err_unlock; 369 370 sigma_delta->irq_dis = false; 371 enable_irq(sigma_delta->spi->irq); 372 373 return 0; 374 375 err_unlock: 376 spi_bus_unlock(sigma_delta->spi->master); 377 err_predisable: 378 379 return ret; 380 } 381 382 static int ad_sd_buffer_postdisable(struct iio_dev *indio_dev) 383 { 384 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 385 386 reinit_completion(&sigma_delta->completion); 387 wait_for_completion_timeout(&sigma_delta->completion, HZ); 388 389 if (!sigma_delta->irq_dis) { 390 disable_irq_nosync(sigma_delta->spi->irq); 391 sigma_delta->irq_dis = true; 392 } 393 394 sigma_delta->keep_cs_asserted = false; 395 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE); 396 397 sigma_delta->bus_locked = false; 398 return spi_bus_unlock(sigma_delta->spi->master); 399 } 400 401 static irqreturn_t ad_sd_trigger_handler(int irq, void *p) 402 { 403 struct iio_poll_func *pf = p; 404 struct iio_dev *indio_dev = pf->indio_dev; 405 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 406 unsigned int reg_size; 407 unsigned int data_reg; 408 uint8_t data[16]; 409 int ret; 410 411 memset(data, 0x00, 16); 412 413 reg_size = indio_dev->channels[0].scan_type.realbits + 414 indio_dev->channels[0].scan_type.shift; 415 reg_size = DIV_ROUND_UP(reg_size, 8); 416 417 if (sigma_delta->info->data_reg != 0) 418 data_reg = sigma_delta->info->data_reg; 419 else 420 data_reg = AD_SD_REG_DATA; 421 422 switch (reg_size) { 423 case 4: 424 case 2: 425 case 1: 426 ret = ad_sd_read_reg_raw(sigma_delta, data_reg, reg_size, 427 &data[0]); 428 break; 429 case 3: 430 /* We store 24 bit samples in a 32 bit word. Keep the upper 431 * byte set to zero. */ 432 ret = ad_sd_read_reg_raw(sigma_delta, data_reg, reg_size, 433 &data[1]); 434 break; 435 } 436 437 iio_push_to_buffers_with_timestamp(indio_dev, data, pf->timestamp); 438 439 iio_trigger_notify_done(indio_dev->trig); 440 sigma_delta->irq_dis = false; 441 enable_irq(sigma_delta->spi->irq); 442 443 return IRQ_HANDLED; 444 } 445 446 static const struct iio_buffer_setup_ops ad_sd_buffer_setup_ops = { 447 .postenable = &ad_sd_buffer_postenable, 448 .predisable = &iio_triggered_buffer_predisable, 449 .postdisable = &ad_sd_buffer_postdisable, 450 .validate_scan_mask = &iio_validate_scan_mask_onehot, 451 }; 452 453 static irqreturn_t ad_sd_data_rdy_trig_poll(int irq, void *private) 454 { 455 struct ad_sigma_delta *sigma_delta = private; 456 457 complete(&sigma_delta->completion); 458 disable_irq_nosync(irq); 459 sigma_delta->irq_dis = true; 460 iio_trigger_poll(sigma_delta->trig); 461 462 return IRQ_HANDLED; 463 } 464 465 /** 466 * ad_sd_validate_trigger() - validate_trigger callback for ad_sigma_delta devices 467 * @indio_dev: The IIO device 468 * @trig: The new trigger 469 * 470 * Returns: 0 if the 'trig' matches the trigger registered by the ad_sigma_delta 471 * device, -EINVAL otherwise. 472 */ 473 int ad_sd_validate_trigger(struct iio_dev *indio_dev, struct iio_trigger *trig) 474 { 475 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 476 477 if (sigma_delta->trig != trig) 478 return -EINVAL; 479 480 return 0; 481 } 482 EXPORT_SYMBOL_GPL(ad_sd_validate_trigger); 483 484 static const struct iio_trigger_ops ad_sd_trigger_ops = { 485 }; 486 487 static int ad_sd_probe_trigger(struct iio_dev *indio_dev) 488 { 489 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 490 int ret; 491 492 sigma_delta->trig = iio_trigger_alloc("%s-dev%d", indio_dev->name, 493 indio_dev->id); 494 if (sigma_delta->trig == NULL) { 495 ret = -ENOMEM; 496 goto error_ret; 497 } 498 sigma_delta->trig->ops = &ad_sd_trigger_ops; 499 init_completion(&sigma_delta->completion); 500 501 ret = request_irq(sigma_delta->spi->irq, 502 ad_sd_data_rdy_trig_poll, 503 IRQF_TRIGGER_LOW, 504 indio_dev->name, 505 sigma_delta); 506 if (ret) 507 goto error_free_trig; 508 509 if (!sigma_delta->irq_dis) { 510 sigma_delta->irq_dis = true; 511 disable_irq_nosync(sigma_delta->spi->irq); 512 } 513 sigma_delta->trig->dev.parent = &sigma_delta->spi->dev; 514 iio_trigger_set_drvdata(sigma_delta->trig, sigma_delta); 515 516 ret = iio_trigger_register(sigma_delta->trig); 517 if (ret) 518 goto error_free_irq; 519 520 /* select default trigger */ 521 indio_dev->trig = iio_trigger_get(sigma_delta->trig); 522 523 return 0; 524 525 error_free_irq: 526 free_irq(sigma_delta->spi->irq, sigma_delta); 527 error_free_trig: 528 iio_trigger_free(sigma_delta->trig); 529 error_ret: 530 return ret; 531 } 532 533 static void ad_sd_remove_trigger(struct iio_dev *indio_dev) 534 { 535 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 536 537 iio_trigger_unregister(sigma_delta->trig); 538 free_irq(sigma_delta->spi->irq, sigma_delta); 539 iio_trigger_free(sigma_delta->trig); 540 } 541 542 /** 543 * ad_sd_setup_buffer_and_trigger() - 544 * @indio_dev: The IIO device 545 */ 546 int ad_sd_setup_buffer_and_trigger(struct iio_dev *indio_dev) 547 { 548 int ret; 549 550 ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time, 551 &ad_sd_trigger_handler, &ad_sd_buffer_setup_ops); 552 if (ret) 553 return ret; 554 555 ret = ad_sd_probe_trigger(indio_dev); 556 if (ret) { 557 iio_triggered_buffer_cleanup(indio_dev); 558 return ret; 559 } 560 561 return 0; 562 } 563 EXPORT_SYMBOL_GPL(ad_sd_setup_buffer_and_trigger); 564 565 /** 566 * ad_sd_cleanup_buffer_and_trigger() - 567 * @indio_dev: The IIO device 568 */ 569 void ad_sd_cleanup_buffer_and_trigger(struct iio_dev *indio_dev) 570 { 571 ad_sd_remove_trigger(indio_dev); 572 iio_triggered_buffer_cleanup(indio_dev); 573 } 574 EXPORT_SYMBOL_GPL(ad_sd_cleanup_buffer_and_trigger); 575 576 /** 577 * ad_sd_init() - Initializes a ad_sigma_delta struct 578 * @sigma_delta: The ad_sigma_delta device 579 * @indio_dev: The IIO device which the Sigma Delta device is used for 580 * @spi: The SPI device for the ad_sigma_delta device 581 * @info: Device specific callbacks and options 582 * 583 * This function needs to be called before any other operations are performed on 584 * the ad_sigma_delta struct. 585 */ 586 int ad_sd_init(struct ad_sigma_delta *sigma_delta, struct iio_dev *indio_dev, 587 struct spi_device *spi, const struct ad_sigma_delta_info *info) 588 { 589 sigma_delta->spi = spi; 590 sigma_delta->info = info; 591 iio_device_set_drvdata(indio_dev, sigma_delta); 592 593 return 0; 594 } 595 EXPORT_SYMBOL_GPL(ad_sd_init); 596 597 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); 598 MODULE_DESCRIPTION("Analog Devices Sigma-Delta ADCs"); 599 MODULE_LICENSE("GPL v2"); 600