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 static int ad_sd_calibrate(struct ad_sigma_delta *sigma_delta, 181 unsigned int mode, unsigned int channel) 182 { 183 int ret; 184 185 ret = ad_sigma_delta_set_channel(sigma_delta, channel); 186 if (ret) 187 return ret; 188 189 spi_bus_lock(sigma_delta->spi->master); 190 sigma_delta->bus_locked = true; 191 reinit_completion(&sigma_delta->completion); 192 193 ret = ad_sigma_delta_set_mode(sigma_delta, mode); 194 if (ret < 0) 195 goto out; 196 197 sigma_delta->irq_dis = false; 198 enable_irq(sigma_delta->spi->irq); 199 ret = wait_for_completion_timeout(&sigma_delta->completion, 2*HZ); 200 if (ret == 0) { 201 sigma_delta->irq_dis = true; 202 disable_irq_nosync(sigma_delta->spi->irq); 203 ret = -EIO; 204 } else { 205 ret = 0; 206 } 207 out: 208 sigma_delta->bus_locked = false; 209 spi_bus_unlock(sigma_delta->spi->master); 210 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE); 211 212 return ret; 213 } 214 215 /** 216 * ad_sd_calibrate_all() - Performs channel calibration 217 * @sigma_delta: The sigma delta device 218 * @cb: Array of channels and calibration type to perform 219 * @n: Number of items in cb 220 * 221 * Returns 0 on success, an error code otherwise. 222 **/ 223 int ad_sd_calibrate_all(struct ad_sigma_delta *sigma_delta, 224 const struct ad_sd_calib_data *cb, unsigned int n) 225 { 226 unsigned int i; 227 int ret; 228 229 for (i = 0; i < n; i++) { 230 ret = ad_sd_calibrate(sigma_delta, cb[i].mode, cb[i].channel); 231 if (ret) 232 return ret; 233 } 234 235 return 0; 236 } 237 EXPORT_SYMBOL_GPL(ad_sd_calibrate_all); 238 239 /** 240 * ad_sigma_delta_single_conversion() - Performs a single data conversion 241 * @indio_dev: The IIO device 242 * @chan: The conversion is done for this channel 243 * @val: Pointer to the location where to store the read value 244 * 245 * Returns: 0 on success, an error value otherwise. 246 */ 247 int ad_sigma_delta_single_conversion(struct iio_dev *indio_dev, 248 const struct iio_chan_spec *chan, int *val) 249 { 250 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 251 unsigned int sample, raw_sample; 252 int ret = 0; 253 254 if (iio_buffer_enabled(indio_dev)) 255 return -EBUSY; 256 257 mutex_lock(&indio_dev->mlock); 258 ad_sigma_delta_set_channel(sigma_delta, chan->address); 259 260 spi_bus_lock(sigma_delta->spi->master); 261 sigma_delta->bus_locked = true; 262 reinit_completion(&sigma_delta->completion); 263 264 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_SINGLE); 265 266 sigma_delta->irq_dis = false; 267 enable_irq(sigma_delta->spi->irq); 268 ret = wait_for_completion_interruptible_timeout( 269 &sigma_delta->completion, HZ); 270 271 sigma_delta->bus_locked = false; 272 spi_bus_unlock(sigma_delta->spi->master); 273 274 if (ret == 0) 275 ret = -EIO; 276 if (ret < 0) 277 goto out; 278 279 ret = ad_sd_read_reg(sigma_delta, AD_SD_REG_DATA, 280 DIV_ROUND_UP(chan->scan_type.realbits + chan->scan_type.shift, 8), 281 &raw_sample); 282 283 out: 284 if (!sigma_delta->irq_dis) { 285 disable_irq_nosync(sigma_delta->spi->irq); 286 sigma_delta->irq_dis = true; 287 } 288 289 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE); 290 mutex_unlock(&indio_dev->mlock); 291 292 if (ret) 293 return ret; 294 295 sample = raw_sample >> chan->scan_type.shift; 296 sample &= (1 << chan->scan_type.realbits) - 1; 297 *val = sample; 298 299 ret = ad_sigma_delta_postprocess_sample(sigma_delta, raw_sample); 300 if (ret) 301 return ret; 302 303 return IIO_VAL_INT; 304 } 305 EXPORT_SYMBOL_GPL(ad_sigma_delta_single_conversion); 306 307 static int ad_sd_buffer_postenable(struct iio_dev *indio_dev) 308 { 309 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 310 unsigned int channel; 311 int ret; 312 313 ret = iio_triggered_buffer_postenable(indio_dev); 314 if (ret < 0) 315 return ret; 316 317 channel = find_first_bit(indio_dev->active_scan_mask, 318 indio_dev->masklength); 319 ret = ad_sigma_delta_set_channel(sigma_delta, 320 indio_dev->channels[channel].address); 321 if (ret) 322 goto err_predisable; 323 324 spi_bus_lock(sigma_delta->spi->master); 325 sigma_delta->bus_locked = true; 326 ret = ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_CONTINUOUS); 327 if (ret) 328 goto err_unlock; 329 330 sigma_delta->irq_dis = false; 331 enable_irq(sigma_delta->spi->irq); 332 333 return 0; 334 335 err_unlock: 336 spi_bus_unlock(sigma_delta->spi->master); 337 err_predisable: 338 339 return ret; 340 } 341 342 static int ad_sd_buffer_postdisable(struct iio_dev *indio_dev) 343 { 344 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 345 346 reinit_completion(&sigma_delta->completion); 347 wait_for_completion_timeout(&sigma_delta->completion, HZ); 348 349 if (!sigma_delta->irq_dis) { 350 disable_irq_nosync(sigma_delta->spi->irq); 351 sigma_delta->irq_dis = true; 352 } 353 354 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE); 355 356 sigma_delta->bus_locked = false; 357 return spi_bus_unlock(sigma_delta->spi->master); 358 } 359 360 static irqreturn_t ad_sd_trigger_handler(int irq, void *p) 361 { 362 struct iio_poll_func *pf = p; 363 struct iio_dev *indio_dev = pf->indio_dev; 364 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 365 unsigned int reg_size; 366 uint8_t data[16]; 367 int ret; 368 369 memset(data, 0x00, 16); 370 371 reg_size = indio_dev->channels[0].scan_type.realbits + 372 indio_dev->channels[0].scan_type.shift; 373 reg_size = DIV_ROUND_UP(reg_size, 8); 374 375 switch (reg_size) { 376 case 4: 377 case 2: 378 case 1: 379 ret = ad_sd_read_reg_raw(sigma_delta, AD_SD_REG_DATA, 380 reg_size, &data[0]); 381 break; 382 case 3: 383 /* We store 24 bit samples in a 32 bit word. Keep the upper 384 * byte set to zero. */ 385 ret = ad_sd_read_reg_raw(sigma_delta, AD_SD_REG_DATA, 386 reg_size, &data[1]); 387 break; 388 } 389 390 iio_push_to_buffers_with_timestamp(indio_dev, data, pf->timestamp); 391 392 iio_trigger_notify_done(indio_dev->trig); 393 sigma_delta->irq_dis = false; 394 enable_irq(sigma_delta->spi->irq); 395 396 return IRQ_HANDLED; 397 } 398 399 static const struct iio_buffer_setup_ops ad_sd_buffer_setup_ops = { 400 .postenable = &ad_sd_buffer_postenable, 401 .predisable = &iio_triggered_buffer_predisable, 402 .postdisable = &ad_sd_buffer_postdisable, 403 .validate_scan_mask = &iio_validate_scan_mask_onehot, 404 }; 405 406 static irqreturn_t ad_sd_data_rdy_trig_poll(int irq, void *private) 407 { 408 struct ad_sigma_delta *sigma_delta = private; 409 410 complete(&sigma_delta->completion); 411 disable_irq_nosync(irq); 412 sigma_delta->irq_dis = true; 413 iio_trigger_poll(sigma_delta->trig, iio_get_time_ns()); 414 415 return IRQ_HANDLED; 416 } 417 418 /** 419 * ad_sd_validate_trigger() - validate_trigger callback for ad_sigma_delta devices 420 * @indio_dev: The IIO device 421 * @trig: The new trigger 422 * 423 * Returns: 0 if the 'trig' matches the trigger registered by the ad_sigma_delta 424 * device, -EINVAL otherwise. 425 */ 426 int ad_sd_validate_trigger(struct iio_dev *indio_dev, struct iio_trigger *trig) 427 { 428 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 429 430 if (sigma_delta->trig != trig) 431 return -EINVAL; 432 433 return 0; 434 } 435 EXPORT_SYMBOL_GPL(ad_sd_validate_trigger); 436 437 static const struct iio_trigger_ops ad_sd_trigger_ops = { 438 .owner = THIS_MODULE, 439 }; 440 441 static int ad_sd_probe_trigger(struct iio_dev *indio_dev) 442 { 443 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 444 int ret; 445 446 sigma_delta->trig = iio_trigger_alloc("%s-dev%d", indio_dev->name, 447 indio_dev->id); 448 if (sigma_delta->trig == NULL) { 449 ret = -ENOMEM; 450 goto error_ret; 451 } 452 sigma_delta->trig->ops = &ad_sd_trigger_ops; 453 init_completion(&sigma_delta->completion); 454 455 ret = request_irq(sigma_delta->spi->irq, 456 ad_sd_data_rdy_trig_poll, 457 IRQF_TRIGGER_LOW, 458 indio_dev->name, 459 sigma_delta); 460 if (ret) 461 goto error_free_trig; 462 463 if (!sigma_delta->irq_dis) { 464 sigma_delta->irq_dis = true; 465 disable_irq_nosync(sigma_delta->spi->irq); 466 } 467 sigma_delta->trig->dev.parent = &sigma_delta->spi->dev; 468 iio_trigger_set_drvdata(sigma_delta->trig, sigma_delta); 469 470 ret = iio_trigger_register(sigma_delta->trig); 471 if (ret) 472 goto error_free_irq; 473 474 /* select default trigger */ 475 indio_dev->trig = sigma_delta->trig; 476 477 return 0; 478 479 error_free_irq: 480 free_irq(sigma_delta->spi->irq, sigma_delta); 481 error_free_trig: 482 iio_trigger_free(sigma_delta->trig); 483 error_ret: 484 return ret; 485 } 486 487 static void ad_sd_remove_trigger(struct iio_dev *indio_dev) 488 { 489 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); 490 491 iio_trigger_unregister(sigma_delta->trig); 492 free_irq(sigma_delta->spi->irq, sigma_delta); 493 iio_trigger_free(sigma_delta->trig); 494 } 495 496 /** 497 * ad_sd_setup_buffer_and_trigger() - 498 * @indio_dev: The IIO device 499 */ 500 int ad_sd_setup_buffer_and_trigger(struct iio_dev *indio_dev) 501 { 502 int ret; 503 504 ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time, 505 &ad_sd_trigger_handler, &ad_sd_buffer_setup_ops); 506 if (ret) 507 return ret; 508 509 ret = ad_sd_probe_trigger(indio_dev); 510 if (ret) { 511 iio_triggered_buffer_cleanup(indio_dev); 512 return ret; 513 } 514 515 return 0; 516 } 517 EXPORT_SYMBOL_GPL(ad_sd_setup_buffer_and_trigger); 518 519 /** 520 * ad_sd_cleanup_buffer_and_trigger() - 521 * @indio_dev: The IIO device 522 */ 523 void ad_sd_cleanup_buffer_and_trigger(struct iio_dev *indio_dev) 524 { 525 ad_sd_remove_trigger(indio_dev); 526 iio_triggered_buffer_cleanup(indio_dev); 527 } 528 EXPORT_SYMBOL_GPL(ad_sd_cleanup_buffer_and_trigger); 529 530 /** 531 * ad_sd_init() - Initializes a ad_sigma_delta struct 532 * @sigma_delta: The ad_sigma_delta device 533 * @indio_dev: The IIO device which the Sigma Delta device is used for 534 * @spi: The SPI device for the ad_sigma_delta device 535 * @info: Device specific callbacks and options 536 * 537 * This function needs to be called before any other operations are performed on 538 * the ad_sigma_delta struct. 539 */ 540 int ad_sd_init(struct ad_sigma_delta *sigma_delta, struct iio_dev *indio_dev, 541 struct spi_device *spi, const struct ad_sigma_delta_info *info) 542 { 543 sigma_delta->spi = spi; 544 sigma_delta->info = info; 545 iio_device_set_drvdata(indio_dev, sigma_delta); 546 547 return 0; 548 } 549 EXPORT_SYMBOL_GPL(ad_sd_init); 550 551 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); 552 MODULE_DESCRIPTION("Analog Devices Sigma-Delta ADCs"); 553 MODULE_LICENSE("GPL v2"); 554