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 put_unaligned_be24(val, &data[1]); 74 break; 75 case 2: 76 put_unaligned_be16(val, &data[1]); 77 break; 78 case 1: 79 data[1] = val; 80 break; 81 case 0: 82 break; 83 default: 84 return -EINVAL; 85 } 86 87 spi_message_init(&m); 88 spi_message_add_tail(&t, &m); 89 90 if (sigma_delta->bus_locked) 91 ret = spi_sync_locked(sigma_delta->spi, &m); 92 else 93 ret = spi_sync(sigma_delta->spi, &m); 94 95 return ret; 96 } 97 EXPORT_SYMBOL_GPL(ad_sd_write_reg); 98 99 static int ad_sd_read_reg_raw(struct ad_sigma_delta *sigma_delta, 100 unsigned int reg, unsigned int size, uint8_t *val) 101 { 102 uint8_t *data = sigma_delta->data; 103 int ret; 104 struct spi_transfer t[] = { 105 { 106 .tx_buf = data, 107 .len = 1, 108 }, { 109 .rx_buf = val, 110 .len = size, 111 .cs_change = sigma_delta->bus_locked, 112 }, 113 }; 114 struct spi_message m; 115 116 spi_message_init(&m); 117 118 if (sigma_delta->info->has_registers) { 119 data[0] = reg << sigma_delta->info->addr_shift; 120 data[0] |= sigma_delta->info->read_mask; 121 data[0] |= sigma_delta->comm; 122 spi_message_add_tail(&t[0], &m); 123 } 124 spi_message_add_tail(&t[1], &m); 125 126 if (sigma_delta->bus_locked) 127 ret = spi_sync_locked(sigma_delta->spi, &m); 128 else 129 ret = spi_sync(sigma_delta->spi, &m); 130 131 return ret; 132 } 133 134 /** 135 * ad_sd_read_reg() - Read a register 136 * 137 * @sigma_delta: The sigma delta device 138 * @reg: Address of the register 139 * @size: Size of the register (1-4) 140 * @val: Read value 141 * 142 * Returns 0 on success, an error code otherwise. 143 **/ 144 int ad_sd_read_reg(struct ad_sigma_delta *sigma_delta, 145 unsigned int reg, unsigned int size, unsigned int *val) 146 { 147 int ret; 148 149 ret = ad_sd_read_reg_raw(sigma_delta, reg, size, sigma_delta->data); 150 if (ret < 0) 151 goto out; 152 153 switch (size) { 154 case 4: 155 *val = get_unaligned_be32(sigma_delta->data); 156 break; 157 case 3: 158 *val = get_unaligned_be24(&sigma_delta->data[0]); 159 break; 160 case 2: 161 *val = get_unaligned_be16(sigma_delta->data); 162 break; 163 case 1: 164 *val = sigma_delta->data[0]; 165 break; 166 default: 167 ret = -EINVAL; 168 break; 169 } 170 171 out: 172 return ret; 173 } 174 EXPORT_SYMBOL_GPL(ad_sd_read_reg); 175 176 /** 177 * ad_sd_reset() - Reset the serial interface 178 * 179 * @sigma_delta: The sigma delta device 180 * @reset_length: Number of SCLKs with DIN = 1 181 * 182 * Returns 0 on success, an error code otherwise. 183 **/ 184 int ad_sd_reset(struct ad_sigma_delta *sigma_delta, 185 unsigned int reset_length) 186 { 187 uint8_t *buf; 188 unsigned int size; 189 int ret; 190 191 size = DIV_ROUND_UP(reset_length, 8); 192 buf = kcalloc(size, sizeof(*buf), GFP_KERNEL); 193 if (!buf) 194 return -ENOMEM; 195 196 memset(buf, 0xff, size); 197 ret = spi_write(sigma_delta->spi, buf, size); 198 kfree(buf); 199 200 return ret; 201 } 202 EXPORT_SYMBOL_GPL(ad_sd_reset); 203 204 int ad_sd_calibrate(struct ad_sigma_delta *sigma_delta, 205 unsigned int mode, unsigned int channel) 206 { 207 int ret; 208 unsigned long timeout; 209 210 ret = ad_sigma_delta_set_channel(sigma_delta, channel); 211 if (ret) 212 return ret; 213 214 spi_bus_lock(sigma_delta->spi->master); 215 sigma_delta->bus_locked = true; 216 sigma_delta->keep_cs_asserted = true; 217 reinit_completion(&sigma_delta->completion); 218 219 ret = ad_sigma_delta_set_mode(sigma_delta, mode); 220 if (ret < 0) 221 goto out; 222 223 sigma_delta->irq_dis = false; 224 enable_irq(sigma_delta->spi->irq); 225 timeout = wait_for_completion_timeout(&sigma_delta->completion, 2 * HZ); 226 if (timeout == 0) { 227 sigma_delta->irq_dis = true; 228 disable_irq_nosync(sigma_delta->spi->irq); 229 ret = -EIO; 230 } else { 231 ret = 0; 232 } 233 out: 234 sigma_delta->keep_cs_asserted = false; 235 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE); 236 sigma_delta->bus_locked = false; 237 spi_bus_unlock(sigma_delta->spi->master); 238 239 return ret; 240 } 241 EXPORT_SYMBOL_GPL(ad_sd_calibrate); 242 243 /** 244 * ad_sd_calibrate_all() - Performs channel calibration 245 * @sigma_delta: The sigma delta device 246 * @cb: Array of channels and calibration type to perform 247 * @n: Number of items in cb 248 * 249 * Returns 0 on success, an error code otherwise. 250 **/ 251 int ad_sd_calibrate_all(struct ad_sigma_delta *sigma_delta, 252 const struct ad_sd_calib_data *cb, unsigned int n) 253 { 254 unsigned int i; 255 int ret; 256 257 for (i = 0; i < n; i++) { 258 ret = ad_sd_calibrate(sigma_delta, cb[i].mode, cb[i].channel); 259 if (ret) 260 return ret; 261 } 262 263 return 0; 264 } 265 EXPORT_SYMBOL_GPL(ad_sd_calibrate_all); 266 267 /** 268 * ad_sigma_delta_single_conversion() - Performs a single data conversion 269 * @indio_dev: The IIO device 270 * @chan: The conversion is done for this channel 271 * @val: Pointer to the location where to store the read value 272 * 273 * Returns: 0 on success, an error value otherwise. 274 */ 275 int ad_sigma_delta_single_conversion(struct iio_dev *indio_dev, 276 const struct iio_chan_spec *chan, int *val) 277 { 278 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 279 unsigned int sample, raw_sample; 280 unsigned int data_reg; 281 int ret = 0; 282 283 if (iio_buffer_enabled(indio_dev)) 284 return -EBUSY; 285 286 mutex_lock(&indio_dev->mlock); 287 ad_sigma_delta_set_channel(sigma_delta, chan->address); 288 289 spi_bus_lock(sigma_delta->spi->master); 290 sigma_delta->bus_locked = true; 291 sigma_delta->keep_cs_asserted = true; 292 reinit_completion(&sigma_delta->completion); 293 294 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_SINGLE); 295 296 sigma_delta->irq_dis = false; 297 enable_irq(sigma_delta->spi->irq); 298 ret = wait_for_completion_interruptible_timeout( 299 &sigma_delta->completion, HZ); 300 301 if (ret == 0) 302 ret = -EIO; 303 if (ret < 0) 304 goto out; 305 306 if (sigma_delta->info->data_reg != 0) 307 data_reg = sigma_delta->info->data_reg; 308 else 309 data_reg = AD_SD_REG_DATA; 310 311 ret = ad_sd_read_reg(sigma_delta, data_reg, 312 DIV_ROUND_UP(chan->scan_type.realbits + chan->scan_type.shift, 8), 313 &raw_sample); 314 315 out: 316 if (!sigma_delta->irq_dis) { 317 disable_irq_nosync(sigma_delta->spi->irq); 318 sigma_delta->irq_dis = true; 319 } 320 321 sigma_delta->keep_cs_asserted = false; 322 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE); 323 sigma_delta->bus_locked = false; 324 spi_bus_unlock(sigma_delta->spi->master); 325 mutex_unlock(&indio_dev->mlock); 326 327 if (ret) 328 return ret; 329 330 sample = raw_sample >> chan->scan_type.shift; 331 sample &= (1 << chan->scan_type.realbits) - 1; 332 *val = sample; 333 334 ret = ad_sigma_delta_postprocess_sample(sigma_delta, raw_sample); 335 if (ret) 336 return ret; 337 338 return IIO_VAL_INT; 339 } 340 EXPORT_SYMBOL_GPL(ad_sigma_delta_single_conversion); 341 342 static int ad_sd_buffer_postenable(struct iio_dev *indio_dev) 343 { 344 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 345 unsigned int channel; 346 int ret; 347 348 channel = find_first_bit(indio_dev->active_scan_mask, 349 indio_dev->masklength); 350 ret = ad_sigma_delta_set_channel(sigma_delta, 351 indio_dev->channels[channel].address); 352 if (ret) 353 return ret; 354 355 spi_bus_lock(sigma_delta->spi->master); 356 sigma_delta->bus_locked = true; 357 sigma_delta->keep_cs_asserted = true; 358 359 ret = ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_CONTINUOUS); 360 if (ret) 361 goto err_unlock; 362 363 sigma_delta->irq_dis = false; 364 enable_irq(sigma_delta->spi->irq); 365 366 return 0; 367 368 err_unlock: 369 spi_bus_unlock(sigma_delta->spi->master); 370 371 return ret; 372 } 373 374 static int ad_sd_buffer_postdisable(struct iio_dev *indio_dev) 375 { 376 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 377 378 reinit_completion(&sigma_delta->completion); 379 wait_for_completion_timeout(&sigma_delta->completion, HZ); 380 381 if (!sigma_delta->irq_dis) { 382 disable_irq_nosync(sigma_delta->spi->irq); 383 sigma_delta->irq_dis = true; 384 } 385 386 sigma_delta->keep_cs_asserted = false; 387 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE); 388 389 sigma_delta->bus_locked = false; 390 return spi_bus_unlock(sigma_delta->spi->master); 391 } 392 393 static irqreturn_t ad_sd_trigger_handler(int irq, void *p) 394 { 395 struct iio_poll_func *pf = p; 396 struct iio_dev *indio_dev = pf->indio_dev; 397 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 398 unsigned int reg_size; 399 unsigned int data_reg; 400 uint8_t data[16]; 401 402 memset(data, 0x00, 16); 403 404 reg_size = indio_dev->channels[0].scan_type.realbits + 405 indio_dev->channels[0].scan_type.shift; 406 reg_size = DIV_ROUND_UP(reg_size, 8); 407 408 if (sigma_delta->info->data_reg != 0) 409 data_reg = sigma_delta->info->data_reg; 410 else 411 data_reg = AD_SD_REG_DATA; 412 413 switch (reg_size) { 414 case 4: 415 case 2: 416 case 1: 417 ad_sd_read_reg_raw(sigma_delta, data_reg, reg_size, &data[0]); 418 break; 419 case 3: 420 /* We store 24 bit samples in a 32 bit word. Keep the upper 421 * byte set to zero. */ 422 ad_sd_read_reg_raw(sigma_delta, data_reg, reg_size, &data[1]); 423 break; 424 } 425 426 iio_push_to_buffers_with_timestamp(indio_dev, data, pf->timestamp); 427 428 iio_trigger_notify_done(indio_dev->trig); 429 sigma_delta->irq_dis = false; 430 enable_irq(sigma_delta->spi->irq); 431 432 return IRQ_HANDLED; 433 } 434 435 static const struct iio_buffer_setup_ops ad_sd_buffer_setup_ops = { 436 .postenable = &ad_sd_buffer_postenable, 437 .postdisable = &ad_sd_buffer_postdisable, 438 .validate_scan_mask = &iio_validate_scan_mask_onehot, 439 }; 440 441 static irqreturn_t ad_sd_data_rdy_trig_poll(int irq, void *private) 442 { 443 struct ad_sigma_delta *sigma_delta = private; 444 445 complete(&sigma_delta->completion); 446 disable_irq_nosync(irq); 447 sigma_delta->irq_dis = true; 448 iio_trigger_poll(sigma_delta->trig); 449 450 return IRQ_HANDLED; 451 } 452 453 /** 454 * ad_sd_validate_trigger() - validate_trigger callback for ad_sigma_delta devices 455 * @indio_dev: The IIO device 456 * @trig: The new trigger 457 * 458 * Returns: 0 if the 'trig' matches the trigger registered by the ad_sigma_delta 459 * device, -EINVAL otherwise. 460 */ 461 int ad_sd_validate_trigger(struct iio_dev *indio_dev, struct iio_trigger *trig) 462 { 463 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 464 465 if (sigma_delta->trig != trig) 466 return -EINVAL; 467 468 return 0; 469 } 470 EXPORT_SYMBOL_GPL(ad_sd_validate_trigger); 471 472 static const struct iio_trigger_ops ad_sd_trigger_ops = { 473 }; 474 475 static int ad_sd_probe_trigger(struct iio_dev *indio_dev) 476 { 477 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 478 int ret; 479 480 sigma_delta->trig = iio_trigger_alloc("%s-dev%d", indio_dev->name, 481 indio_dev->id); 482 if (sigma_delta->trig == NULL) { 483 ret = -ENOMEM; 484 goto error_ret; 485 } 486 sigma_delta->trig->ops = &ad_sd_trigger_ops; 487 init_completion(&sigma_delta->completion); 488 489 ret = request_irq(sigma_delta->spi->irq, 490 ad_sd_data_rdy_trig_poll, 491 sigma_delta->info->irq_flags, 492 indio_dev->name, 493 sigma_delta); 494 if (ret) 495 goto error_free_trig; 496 497 if (!sigma_delta->irq_dis) { 498 sigma_delta->irq_dis = true; 499 disable_irq_nosync(sigma_delta->spi->irq); 500 } 501 sigma_delta->trig->dev.parent = &sigma_delta->spi->dev; 502 iio_trigger_set_drvdata(sigma_delta->trig, sigma_delta); 503 504 ret = iio_trigger_register(sigma_delta->trig); 505 if (ret) 506 goto error_free_irq; 507 508 /* select default trigger */ 509 indio_dev->trig = iio_trigger_get(sigma_delta->trig); 510 511 return 0; 512 513 error_free_irq: 514 free_irq(sigma_delta->spi->irq, sigma_delta); 515 error_free_trig: 516 iio_trigger_free(sigma_delta->trig); 517 error_ret: 518 return ret; 519 } 520 521 static void ad_sd_remove_trigger(struct iio_dev *indio_dev) 522 { 523 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 524 525 iio_trigger_unregister(sigma_delta->trig); 526 free_irq(sigma_delta->spi->irq, sigma_delta); 527 iio_trigger_free(sigma_delta->trig); 528 } 529 530 /** 531 * ad_sd_setup_buffer_and_trigger() - 532 * @indio_dev: The IIO device 533 */ 534 int ad_sd_setup_buffer_and_trigger(struct iio_dev *indio_dev) 535 { 536 int ret; 537 538 ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time, 539 &ad_sd_trigger_handler, &ad_sd_buffer_setup_ops); 540 if (ret) 541 return ret; 542 543 ret = ad_sd_probe_trigger(indio_dev); 544 if (ret) { 545 iio_triggered_buffer_cleanup(indio_dev); 546 return ret; 547 } 548 549 return 0; 550 } 551 EXPORT_SYMBOL_GPL(ad_sd_setup_buffer_and_trigger); 552 553 /** 554 * ad_sd_cleanup_buffer_and_trigger() - 555 * @indio_dev: The IIO device 556 */ 557 void ad_sd_cleanup_buffer_and_trigger(struct iio_dev *indio_dev) 558 { 559 ad_sd_remove_trigger(indio_dev); 560 iio_triggered_buffer_cleanup(indio_dev); 561 } 562 EXPORT_SYMBOL_GPL(ad_sd_cleanup_buffer_and_trigger); 563 564 /** 565 * ad_sd_init() - Initializes a ad_sigma_delta struct 566 * @sigma_delta: The ad_sigma_delta device 567 * @indio_dev: The IIO device which the Sigma Delta device is used for 568 * @spi: The SPI device for the ad_sigma_delta device 569 * @info: Device specific callbacks and options 570 * 571 * This function needs to be called before any other operations are performed on 572 * the ad_sigma_delta struct. 573 */ 574 int ad_sd_init(struct ad_sigma_delta *sigma_delta, struct iio_dev *indio_dev, 575 struct spi_device *spi, const struct ad_sigma_delta_info *info) 576 { 577 sigma_delta->spi = spi; 578 sigma_delta->info = info; 579 iio_device_set_drvdata(indio_dev, sigma_delta); 580 581 return 0; 582 } 583 EXPORT_SYMBOL_GPL(ad_sd_init); 584 585 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); 586 MODULE_DESCRIPTION("Analog Devices Sigma-Delta ADCs"); 587 MODULE_LICENSE("GPL v2"); 588