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; 212 213 ret = ad_sigma_delta_set_channel(sigma_delta, channel); 214 if (ret) 215 return ret; 216 217 spi_bus_lock(sigma_delta->spi->master); 218 sigma_delta->bus_locked = true; 219 reinit_completion(&sigma_delta->completion); 220 221 ret = ad_sigma_delta_set_mode(sigma_delta, mode); 222 if (ret < 0) 223 goto out; 224 225 sigma_delta->irq_dis = false; 226 enable_irq(sigma_delta->spi->irq); 227 ret = wait_for_completion_timeout(&sigma_delta->completion, 2*HZ); 228 if (ret == 0) { 229 sigma_delta->irq_dis = true; 230 disable_irq_nosync(sigma_delta->spi->irq); 231 ret = -EIO; 232 } else { 233 ret = 0; 234 } 235 out: 236 sigma_delta->bus_locked = false; 237 spi_bus_unlock(sigma_delta->spi->master); 238 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE); 239 240 return ret; 241 } 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 int ret = 0; 281 282 if (iio_buffer_enabled(indio_dev)) 283 return -EBUSY; 284 285 mutex_lock(&indio_dev->mlock); 286 ad_sigma_delta_set_channel(sigma_delta, chan->address); 287 288 spi_bus_lock(sigma_delta->spi->master); 289 sigma_delta->bus_locked = true; 290 reinit_completion(&sigma_delta->completion); 291 292 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_SINGLE); 293 294 sigma_delta->irq_dis = false; 295 enable_irq(sigma_delta->spi->irq); 296 ret = wait_for_completion_interruptible_timeout( 297 &sigma_delta->completion, HZ); 298 299 sigma_delta->bus_locked = false; 300 spi_bus_unlock(sigma_delta->spi->master); 301 302 if (ret == 0) 303 ret = -EIO; 304 if (ret < 0) 305 goto out; 306 307 ret = ad_sd_read_reg(sigma_delta, AD_SD_REG_DATA, 308 DIV_ROUND_UP(chan->scan_type.realbits + chan->scan_type.shift, 8), 309 &raw_sample); 310 311 out: 312 if (!sigma_delta->irq_dis) { 313 disable_irq_nosync(sigma_delta->spi->irq); 314 sigma_delta->irq_dis = true; 315 } 316 317 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE); 318 mutex_unlock(&indio_dev->mlock); 319 320 if (ret) 321 return ret; 322 323 sample = raw_sample >> chan->scan_type.shift; 324 sample &= (1 << chan->scan_type.realbits) - 1; 325 *val = sample; 326 327 ret = ad_sigma_delta_postprocess_sample(sigma_delta, raw_sample); 328 if (ret) 329 return ret; 330 331 return IIO_VAL_INT; 332 } 333 EXPORT_SYMBOL_GPL(ad_sigma_delta_single_conversion); 334 335 static int ad_sd_buffer_postenable(struct iio_dev *indio_dev) 336 { 337 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 338 unsigned int channel; 339 int ret; 340 341 ret = iio_triggered_buffer_postenable(indio_dev); 342 if (ret < 0) 343 return ret; 344 345 channel = find_first_bit(indio_dev->active_scan_mask, 346 indio_dev->masklength); 347 ret = ad_sigma_delta_set_channel(sigma_delta, 348 indio_dev->channels[channel].address); 349 if (ret) 350 goto err_predisable; 351 352 spi_bus_lock(sigma_delta->spi->master); 353 sigma_delta->bus_locked = true; 354 ret = ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_CONTINUOUS); 355 if (ret) 356 goto err_unlock; 357 358 sigma_delta->irq_dis = false; 359 enable_irq(sigma_delta->spi->irq); 360 361 return 0; 362 363 err_unlock: 364 spi_bus_unlock(sigma_delta->spi->master); 365 err_predisable: 366 367 return ret; 368 } 369 370 static int ad_sd_buffer_postdisable(struct iio_dev *indio_dev) 371 { 372 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 373 374 reinit_completion(&sigma_delta->completion); 375 wait_for_completion_timeout(&sigma_delta->completion, HZ); 376 377 if (!sigma_delta->irq_dis) { 378 disable_irq_nosync(sigma_delta->spi->irq); 379 sigma_delta->irq_dis = true; 380 } 381 382 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE); 383 384 sigma_delta->bus_locked = false; 385 return spi_bus_unlock(sigma_delta->spi->master); 386 } 387 388 static irqreturn_t ad_sd_trigger_handler(int irq, void *p) 389 { 390 struct iio_poll_func *pf = p; 391 struct iio_dev *indio_dev = pf->indio_dev; 392 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 393 unsigned int reg_size; 394 uint8_t data[16]; 395 int ret; 396 397 memset(data, 0x00, 16); 398 399 reg_size = indio_dev->channels[0].scan_type.realbits + 400 indio_dev->channels[0].scan_type.shift; 401 reg_size = DIV_ROUND_UP(reg_size, 8); 402 403 switch (reg_size) { 404 case 4: 405 case 2: 406 case 1: 407 ret = ad_sd_read_reg_raw(sigma_delta, AD_SD_REG_DATA, 408 reg_size, &data[0]); 409 break; 410 case 3: 411 /* We store 24 bit samples in a 32 bit word. Keep the upper 412 * byte set to zero. */ 413 ret = ad_sd_read_reg_raw(sigma_delta, AD_SD_REG_DATA, 414 reg_size, &data[1]); 415 break; 416 } 417 418 iio_push_to_buffers_with_timestamp(indio_dev, data, pf->timestamp); 419 420 iio_trigger_notify_done(indio_dev->trig); 421 sigma_delta->irq_dis = false; 422 enable_irq(sigma_delta->spi->irq); 423 424 return IRQ_HANDLED; 425 } 426 427 static const struct iio_buffer_setup_ops ad_sd_buffer_setup_ops = { 428 .postenable = &ad_sd_buffer_postenable, 429 .predisable = &iio_triggered_buffer_predisable, 430 .postdisable = &ad_sd_buffer_postdisable, 431 .validate_scan_mask = &iio_validate_scan_mask_onehot, 432 }; 433 434 static irqreturn_t ad_sd_data_rdy_trig_poll(int irq, void *private) 435 { 436 struct ad_sigma_delta *sigma_delta = private; 437 438 complete(&sigma_delta->completion); 439 disable_irq_nosync(irq); 440 sigma_delta->irq_dis = true; 441 iio_trigger_poll(sigma_delta->trig); 442 443 return IRQ_HANDLED; 444 } 445 446 /** 447 * ad_sd_validate_trigger() - validate_trigger callback for ad_sigma_delta devices 448 * @indio_dev: The IIO device 449 * @trig: The new trigger 450 * 451 * Returns: 0 if the 'trig' matches the trigger registered by the ad_sigma_delta 452 * device, -EINVAL otherwise. 453 */ 454 int ad_sd_validate_trigger(struct iio_dev *indio_dev, struct iio_trigger *trig) 455 { 456 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 457 458 if (sigma_delta->trig != trig) 459 return -EINVAL; 460 461 return 0; 462 } 463 EXPORT_SYMBOL_GPL(ad_sd_validate_trigger); 464 465 static const struct iio_trigger_ops ad_sd_trigger_ops = { 466 }; 467 468 static int ad_sd_probe_trigger(struct iio_dev *indio_dev) 469 { 470 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 471 int ret; 472 473 sigma_delta->trig = iio_trigger_alloc("%s-dev%d", indio_dev->name, 474 indio_dev->id); 475 if (sigma_delta->trig == NULL) { 476 ret = -ENOMEM; 477 goto error_ret; 478 } 479 sigma_delta->trig->ops = &ad_sd_trigger_ops; 480 init_completion(&sigma_delta->completion); 481 482 ret = request_irq(sigma_delta->spi->irq, 483 ad_sd_data_rdy_trig_poll, 484 IRQF_TRIGGER_LOW, 485 indio_dev->name, 486 sigma_delta); 487 if (ret) 488 goto error_free_trig; 489 490 if (!sigma_delta->irq_dis) { 491 sigma_delta->irq_dis = true; 492 disable_irq_nosync(sigma_delta->spi->irq); 493 } 494 sigma_delta->trig->dev.parent = &sigma_delta->spi->dev; 495 iio_trigger_set_drvdata(sigma_delta->trig, sigma_delta); 496 497 ret = iio_trigger_register(sigma_delta->trig); 498 if (ret) 499 goto error_free_irq; 500 501 /* select default trigger */ 502 indio_dev->trig = iio_trigger_get(sigma_delta->trig); 503 504 return 0; 505 506 error_free_irq: 507 free_irq(sigma_delta->spi->irq, sigma_delta); 508 error_free_trig: 509 iio_trigger_free(sigma_delta->trig); 510 error_ret: 511 return ret; 512 } 513 514 static void ad_sd_remove_trigger(struct iio_dev *indio_dev) 515 { 516 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 517 518 iio_trigger_unregister(sigma_delta->trig); 519 free_irq(sigma_delta->spi->irq, sigma_delta); 520 iio_trigger_free(sigma_delta->trig); 521 } 522 523 /** 524 * ad_sd_setup_buffer_and_trigger() - 525 * @indio_dev: The IIO device 526 */ 527 int ad_sd_setup_buffer_and_trigger(struct iio_dev *indio_dev) 528 { 529 int ret; 530 531 ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time, 532 &ad_sd_trigger_handler, &ad_sd_buffer_setup_ops); 533 if (ret) 534 return ret; 535 536 ret = ad_sd_probe_trigger(indio_dev); 537 if (ret) { 538 iio_triggered_buffer_cleanup(indio_dev); 539 return ret; 540 } 541 542 return 0; 543 } 544 EXPORT_SYMBOL_GPL(ad_sd_setup_buffer_and_trigger); 545 546 /** 547 * ad_sd_cleanup_buffer_and_trigger() - 548 * @indio_dev: The IIO device 549 */ 550 void ad_sd_cleanup_buffer_and_trigger(struct iio_dev *indio_dev) 551 { 552 ad_sd_remove_trigger(indio_dev); 553 iio_triggered_buffer_cleanup(indio_dev); 554 } 555 EXPORT_SYMBOL_GPL(ad_sd_cleanup_buffer_and_trigger); 556 557 /** 558 * ad_sd_init() - Initializes a ad_sigma_delta struct 559 * @sigma_delta: The ad_sigma_delta device 560 * @indio_dev: The IIO device which the Sigma Delta device is used for 561 * @spi: The SPI device for the ad_sigma_delta device 562 * @info: Device specific callbacks and options 563 * 564 * This function needs to be called before any other operations are performed on 565 * the ad_sigma_delta struct. 566 */ 567 int ad_sd_init(struct ad_sigma_delta *sigma_delta, struct iio_dev *indio_dev, 568 struct spi_device *spi, const struct ad_sigma_delta_info *info) 569 { 570 sigma_delta->spi = spi; 571 sigma_delta->info = info; 572 iio_device_set_drvdata(indio_dev, sigma_delta); 573 574 return 0; 575 } 576 EXPORT_SYMBOL_GPL(ad_sd_init); 577 578 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); 579 MODULE_DESCRIPTION("Analog Devices Sigma-Delta ADCs"); 580 MODULE_LICENSE("GPL v2"); 581