1 /* 2 * Support code for Analog Devices Sigma-Delta ADCs 3 * 4 * Copyright 2012 Analog Devices Inc. 5 * Author: Lars-Peter Clausen <lars@metafoo.de> 6 * 7 * Licensed under the GPL-2. 8 */ 9 10 #include <linux/interrupt.h> 11 #include <linux/device.h> 12 #include <linux/kernel.h> 13 #include <linux/slab.h> 14 #include <linux/spi/spi.h> 15 #include <linux/err.h> 16 #include <linux/module.h> 17 18 #include <linux/iio/iio.h> 19 #include <linux/iio/sysfs.h> 20 #include <linux/iio/buffer.h> 21 #include <linux/iio/trigger.h> 22 #include <linux/iio/trigger_consumer.h> 23 #include <linux/iio/triggered_buffer.h> 24 #include <linux/iio/adc/ad_sigma_delta.h> 25 26 #include <asm/unaligned.h> 27 28 29 #define AD_SD_COMM_CHAN_MASK 0x3 30 31 #define AD_SD_REG_COMM 0x00 32 #define AD_SD_REG_DATA 0x03 33 34 /** 35 * ad_sd_set_comm() - Set communications register 36 * 37 * @sigma_delta: The sigma delta device 38 * @comm: New value for the communications register 39 */ 40 void ad_sd_set_comm(struct ad_sigma_delta *sigma_delta, uint8_t comm) 41 { 42 /* Some variants use the lower two bits of the communications register 43 * to select the channel */ 44 sigma_delta->comm = comm & AD_SD_COMM_CHAN_MASK; 45 } 46 EXPORT_SYMBOL_GPL(ad_sd_set_comm); 47 48 /** 49 * ad_sd_write_reg() - Write a register 50 * 51 * @sigma_delta: The sigma delta device 52 * @reg: Address of the register 53 * @size: Size of the register (0-3) 54 * @val: Value to write to the register 55 * 56 * Returns 0 on success, an error code otherwise. 57 **/ 58 int ad_sd_write_reg(struct ad_sigma_delta *sigma_delta, unsigned int reg, 59 unsigned int size, unsigned int val) 60 { 61 uint8_t *data = sigma_delta->data; 62 struct spi_transfer t = { 63 .tx_buf = data, 64 .len = size + 1, 65 .cs_change = sigma_delta->bus_locked, 66 }; 67 struct spi_message m; 68 int ret; 69 70 data[0] = (reg << sigma_delta->info->addr_shift) | sigma_delta->comm; 71 72 switch (size) { 73 case 3: 74 data[1] = val >> 16; 75 data[2] = val >> 8; 76 data[3] = val; 77 break; 78 case 2: 79 put_unaligned_be16(val, &data[1]); 80 break; 81 case 1: 82 data[1] = val; 83 break; 84 case 0: 85 break; 86 default: 87 return -EINVAL; 88 } 89 90 spi_message_init(&m); 91 spi_message_add_tail(&t, &m); 92 93 if (sigma_delta->bus_locked) 94 ret = spi_sync_locked(sigma_delta->spi, &m); 95 else 96 ret = spi_sync(sigma_delta->spi, &m); 97 98 return ret; 99 } 100 EXPORT_SYMBOL_GPL(ad_sd_write_reg); 101 102 static int ad_sd_read_reg_raw(struct ad_sigma_delta *sigma_delta, 103 unsigned int reg, unsigned int size, uint8_t *val) 104 { 105 uint8_t *data = sigma_delta->data; 106 int ret; 107 struct spi_transfer t[] = { 108 { 109 .tx_buf = data, 110 .len = 1, 111 }, { 112 .rx_buf = val, 113 .len = size, 114 .cs_change = sigma_delta->bus_locked, 115 }, 116 }; 117 struct spi_message m; 118 119 spi_message_init(&m); 120 121 if (sigma_delta->info->has_registers) { 122 data[0] = reg << sigma_delta->info->addr_shift; 123 data[0] |= sigma_delta->info->read_mask; 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 reinit_completion(&sigma_delta->completion); 221 222 ret = ad_sigma_delta_set_mode(sigma_delta, mode); 223 if (ret < 0) 224 goto out; 225 226 sigma_delta->irq_dis = false; 227 enable_irq(sigma_delta->spi->irq); 228 timeout = wait_for_completion_timeout(&sigma_delta->completion, 2 * HZ); 229 if (timeout == 0) { 230 sigma_delta->irq_dis = true; 231 disable_irq_nosync(sigma_delta->spi->irq); 232 ret = -EIO; 233 } else { 234 ret = 0; 235 } 236 out: 237 sigma_delta->bus_locked = false; 238 spi_bus_unlock(sigma_delta->spi->master); 239 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE); 240 241 return ret; 242 } 243 244 /** 245 * ad_sd_calibrate_all() - Performs channel calibration 246 * @sigma_delta: The sigma delta device 247 * @cb: Array of channels and calibration type to perform 248 * @n: Number of items in cb 249 * 250 * Returns 0 on success, an error code otherwise. 251 **/ 252 int ad_sd_calibrate_all(struct ad_sigma_delta *sigma_delta, 253 const struct ad_sd_calib_data *cb, unsigned int n) 254 { 255 unsigned int i; 256 int ret; 257 258 for (i = 0; i < n; i++) { 259 ret = ad_sd_calibrate(sigma_delta, cb[i].mode, cb[i].channel); 260 if (ret) 261 return ret; 262 } 263 264 return 0; 265 } 266 EXPORT_SYMBOL_GPL(ad_sd_calibrate_all); 267 268 /** 269 * ad_sigma_delta_single_conversion() - Performs a single data conversion 270 * @indio_dev: The IIO device 271 * @chan: The conversion is done for this channel 272 * @val: Pointer to the location where to store the read value 273 * 274 * Returns: 0 on success, an error value otherwise. 275 */ 276 int ad_sigma_delta_single_conversion(struct iio_dev *indio_dev, 277 const struct iio_chan_spec *chan, int *val) 278 { 279 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 280 unsigned int sample, raw_sample; 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 reinit_completion(&sigma_delta->completion); 292 293 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_SINGLE); 294 295 sigma_delta->irq_dis = false; 296 enable_irq(sigma_delta->spi->irq); 297 ret = wait_for_completion_interruptible_timeout( 298 &sigma_delta->completion, HZ); 299 300 sigma_delta->bus_locked = false; 301 spi_bus_unlock(sigma_delta->spi->master); 302 303 if (ret == 0) 304 ret = -EIO; 305 if (ret < 0) 306 goto out; 307 308 ret = ad_sd_read_reg(sigma_delta, AD_SD_REG_DATA, 309 DIV_ROUND_UP(chan->scan_type.realbits + chan->scan_type.shift, 8), 310 &raw_sample); 311 312 out: 313 if (!sigma_delta->irq_dis) { 314 disable_irq_nosync(sigma_delta->spi->irq); 315 sigma_delta->irq_dis = true; 316 } 317 318 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE); 319 mutex_unlock(&indio_dev->mlock); 320 321 if (ret) 322 return ret; 323 324 sample = raw_sample >> chan->scan_type.shift; 325 sample &= (1 << chan->scan_type.realbits) - 1; 326 *val = sample; 327 328 ret = ad_sigma_delta_postprocess_sample(sigma_delta, raw_sample); 329 if (ret) 330 return ret; 331 332 return IIO_VAL_INT; 333 } 334 EXPORT_SYMBOL_GPL(ad_sigma_delta_single_conversion); 335 336 static int ad_sd_buffer_postenable(struct iio_dev *indio_dev) 337 { 338 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 339 unsigned int channel; 340 int ret; 341 342 ret = iio_triggered_buffer_postenable(indio_dev); 343 if (ret < 0) 344 return ret; 345 346 channel = find_first_bit(indio_dev->active_scan_mask, 347 indio_dev->masklength); 348 ret = ad_sigma_delta_set_channel(sigma_delta, 349 indio_dev->channels[channel].address); 350 if (ret) 351 goto err_predisable; 352 353 spi_bus_lock(sigma_delta->spi->master); 354 sigma_delta->bus_locked = true; 355 ret = ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_CONTINUOUS); 356 if (ret) 357 goto err_unlock; 358 359 sigma_delta->irq_dis = false; 360 enable_irq(sigma_delta->spi->irq); 361 362 return 0; 363 364 err_unlock: 365 spi_bus_unlock(sigma_delta->spi->master); 366 err_predisable: 367 368 return ret; 369 } 370 371 static int ad_sd_buffer_postdisable(struct iio_dev *indio_dev) 372 { 373 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 374 375 reinit_completion(&sigma_delta->completion); 376 wait_for_completion_timeout(&sigma_delta->completion, HZ); 377 378 if (!sigma_delta->irq_dis) { 379 disable_irq_nosync(sigma_delta->spi->irq); 380 sigma_delta->irq_dis = true; 381 } 382 383 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE); 384 385 sigma_delta->bus_locked = false; 386 return spi_bus_unlock(sigma_delta->spi->master); 387 } 388 389 static irqreturn_t ad_sd_trigger_handler(int irq, void *p) 390 { 391 struct iio_poll_func *pf = p; 392 struct iio_dev *indio_dev = pf->indio_dev; 393 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 394 unsigned int reg_size; 395 uint8_t data[16]; 396 int ret; 397 398 memset(data, 0x00, 16); 399 400 reg_size = indio_dev->channels[0].scan_type.realbits + 401 indio_dev->channels[0].scan_type.shift; 402 reg_size = DIV_ROUND_UP(reg_size, 8); 403 404 switch (reg_size) { 405 case 4: 406 case 2: 407 case 1: 408 ret = ad_sd_read_reg_raw(sigma_delta, AD_SD_REG_DATA, 409 reg_size, &data[0]); 410 break; 411 case 3: 412 /* We store 24 bit samples in a 32 bit word. Keep the upper 413 * byte set to zero. */ 414 ret = ad_sd_read_reg_raw(sigma_delta, AD_SD_REG_DATA, 415 reg_size, &data[1]); 416 break; 417 } 418 419 iio_push_to_buffers_with_timestamp(indio_dev, data, pf->timestamp); 420 421 iio_trigger_notify_done(indio_dev->trig); 422 sigma_delta->irq_dis = false; 423 enable_irq(sigma_delta->spi->irq); 424 425 return IRQ_HANDLED; 426 } 427 428 static const struct iio_buffer_setup_ops ad_sd_buffer_setup_ops = { 429 .postenable = &ad_sd_buffer_postenable, 430 .predisable = &iio_triggered_buffer_predisable, 431 .postdisable = &ad_sd_buffer_postdisable, 432 .validate_scan_mask = &iio_validate_scan_mask_onehot, 433 }; 434 435 static irqreturn_t ad_sd_data_rdy_trig_poll(int irq, void *private) 436 { 437 struct ad_sigma_delta *sigma_delta = private; 438 439 complete(&sigma_delta->completion); 440 disable_irq_nosync(irq); 441 sigma_delta->irq_dis = true; 442 iio_trigger_poll(sigma_delta->trig); 443 444 return IRQ_HANDLED; 445 } 446 447 /** 448 * ad_sd_validate_trigger() - validate_trigger callback for ad_sigma_delta devices 449 * @indio_dev: The IIO device 450 * @trig: The new trigger 451 * 452 * Returns: 0 if the 'trig' matches the trigger registered by the ad_sigma_delta 453 * device, -EINVAL otherwise. 454 */ 455 int ad_sd_validate_trigger(struct iio_dev *indio_dev, struct iio_trigger *trig) 456 { 457 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 458 459 if (sigma_delta->trig != trig) 460 return -EINVAL; 461 462 return 0; 463 } 464 EXPORT_SYMBOL_GPL(ad_sd_validate_trigger); 465 466 static const struct iio_trigger_ops ad_sd_trigger_ops = { 467 }; 468 469 static int ad_sd_probe_trigger(struct iio_dev *indio_dev) 470 { 471 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 472 int ret; 473 474 sigma_delta->trig = iio_trigger_alloc("%s-dev%d", indio_dev->name, 475 indio_dev->id); 476 if (sigma_delta->trig == NULL) { 477 ret = -ENOMEM; 478 goto error_ret; 479 } 480 sigma_delta->trig->ops = &ad_sd_trigger_ops; 481 init_completion(&sigma_delta->completion); 482 483 ret = request_irq(sigma_delta->spi->irq, 484 ad_sd_data_rdy_trig_poll, 485 IRQF_TRIGGER_LOW, 486 indio_dev->name, 487 sigma_delta); 488 if (ret) 489 goto error_free_trig; 490 491 if (!sigma_delta->irq_dis) { 492 sigma_delta->irq_dis = true; 493 disable_irq_nosync(sigma_delta->spi->irq); 494 } 495 sigma_delta->trig->dev.parent = &sigma_delta->spi->dev; 496 iio_trigger_set_drvdata(sigma_delta->trig, sigma_delta); 497 498 ret = iio_trigger_register(sigma_delta->trig); 499 if (ret) 500 goto error_free_irq; 501 502 /* select default trigger */ 503 indio_dev->trig = iio_trigger_get(sigma_delta->trig); 504 505 return 0; 506 507 error_free_irq: 508 free_irq(sigma_delta->spi->irq, sigma_delta); 509 error_free_trig: 510 iio_trigger_free(sigma_delta->trig); 511 error_ret: 512 return ret; 513 } 514 515 static void ad_sd_remove_trigger(struct iio_dev *indio_dev) 516 { 517 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 518 519 iio_trigger_unregister(sigma_delta->trig); 520 free_irq(sigma_delta->spi->irq, sigma_delta); 521 iio_trigger_free(sigma_delta->trig); 522 } 523 524 /** 525 * ad_sd_setup_buffer_and_trigger() - 526 * @indio_dev: The IIO device 527 */ 528 int ad_sd_setup_buffer_and_trigger(struct iio_dev *indio_dev) 529 { 530 int ret; 531 532 ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time, 533 &ad_sd_trigger_handler, &ad_sd_buffer_setup_ops); 534 if (ret) 535 return ret; 536 537 ret = ad_sd_probe_trigger(indio_dev); 538 if (ret) { 539 iio_triggered_buffer_cleanup(indio_dev); 540 return ret; 541 } 542 543 return 0; 544 } 545 EXPORT_SYMBOL_GPL(ad_sd_setup_buffer_and_trigger); 546 547 /** 548 * ad_sd_cleanup_buffer_and_trigger() - 549 * @indio_dev: The IIO device 550 */ 551 void ad_sd_cleanup_buffer_and_trigger(struct iio_dev *indio_dev) 552 { 553 ad_sd_remove_trigger(indio_dev); 554 iio_triggered_buffer_cleanup(indio_dev); 555 } 556 EXPORT_SYMBOL_GPL(ad_sd_cleanup_buffer_and_trigger); 557 558 /** 559 * ad_sd_init() - Initializes a ad_sigma_delta struct 560 * @sigma_delta: The ad_sigma_delta device 561 * @indio_dev: The IIO device which the Sigma Delta device is used for 562 * @spi: The SPI device for the ad_sigma_delta device 563 * @info: Device specific callbacks and options 564 * 565 * This function needs to be called before any other operations are performed on 566 * the ad_sigma_delta struct. 567 */ 568 int ad_sd_init(struct ad_sigma_delta *sigma_delta, struct iio_dev *indio_dev, 569 struct spi_device *spi, const struct ad_sigma_delta_info *info) 570 { 571 sigma_delta->spi = spi; 572 sigma_delta->info = info; 573 iio_device_set_drvdata(indio_dev, sigma_delta); 574 575 return 0; 576 } 577 EXPORT_SYMBOL_GPL(ad_sd_init); 578 579 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); 580 MODULE_DESCRIPTION("Analog Devices Sigma-Delta ADCs"); 581 MODULE_LICENSE("GPL v2"); 582