1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * ADC12130/ADC12132/ADC12138 12-bit plus sign ADC driver 4 * 5 * Copyright (c) 2016 Akinobu Mita <akinobu.mita@gmail.com> 6 * 7 * Datasheet: http://www.ti.com/lit/ds/symlink/adc12138.pdf 8 */ 9 10 #include <linux/module.h> 11 #include <linux/interrupt.h> 12 #include <linux/completion.h> 13 #include <linux/clk.h> 14 #include <linux/property.h> 15 #include <linux/spi/spi.h> 16 #include <linux/iio/iio.h> 17 #include <linux/iio/buffer.h> 18 #include <linux/iio/trigger.h> 19 #include <linux/iio/triggered_buffer.h> 20 #include <linux/iio/trigger_consumer.h> 21 #include <linux/regulator/consumer.h> 22 23 #define ADC12138_MODE_AUTO_CAL 0x08 24 #define ADC12138_MODE_READ_STATUS 0x0c 25 #define ADC12138_MODE_ACQUISITION_TIME_6 0x0e 26 #define ADC12138_MODE_ACQUISITION_TIME_10 0x4e 27 #define ADC12138_MODE_ACQUISITION_TIME_18 0x8e 28 #define ADC12138_MODE_ACQUISITION_TIME_34 0xce 29 30 #define ADC12138_STATUS_CAL BIT(6) 31 32 enum { 33 adc12130, 34 adc12132, 35 adc12138, 36 }; 37 38 struct adc12138 { 39 struct spi_device *spi; 40 unsigned int id; 41 /* conversion clock */ 42 struct clk *cclk; 43 /* positive analog voltage reference */ 44 struct regulator *vref_p; 45 /* negative analog voltage reference */ 46 struct regulator *vref_n; 47 struct mutex lock; 48 struct completion complete; 49 /* The number of cclk periods for the S/H's acquisition time */ 50 unsigned int acquisition_time; 51 /* 52 * Maximum size needed: 16x 2 bytes ADC data + 8 bytes timestamp. 53 * Less may be need if not all channels are enabled, as long as 54 * the 8 byte alignment of the timestamp is maintained. 55 */ 56 __be16 data[20] __aligned(8); 57 58 u8 tx_buf[2] __aligned(IIO_DMA_MINALIGN); 59 u8 rx_buf[2]; 60 }; 61 62 #define ADC12138_VOLTAGE_CHANNEL(chan) \ 63 { \ 64 .type = IIO_VOLTAGE, \ 65 .indexed = 1, \ 66 .channel = chan, \ 67 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 68 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \ 69 | BIT(IIO_CHAN_INFO_OFFSET), \ 70 .scan_index = chan, \ 71 .scan_type = { \ 72 .sign = 's', \ 73 .realbits = 13, \ 74 .storagebits = 16, \ 75 .shift = 3, \ 76 .endianness = IIO_BE, \ 77 }, \ 78 } 79 80 #define ADC12138_VOLTAGE_CHANNEL_DIFF(chan1, chan2, si) \ 81 { \ 82 .type = IIO_VOLTAGE, \ 83 .indexed = 1, \ 84 .channel = (chan1), \ 85 .channel2 = (chan2), \ 86 .differential = 1, \ 87 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 88 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \ 89 | BIT(IIO_CHAN_INFO_OFFSET), \ 90 .scan_index = si, \ 91 .scan_type = { \ 92 .sign = 's', \ 93 .realbits = 13, \ 94 .storagebits = 16, \ 95 .shift = 3, \ 96 .endianness = IIO_BE, \ 97 }, \ 98 } 99 100 static const struct iio_chan_spec adc12132_channels[] = { 101 ADC12138_VOLTAGE_CHANNEL(0), 102 ADC12138_VOLTAGE_CHANNEL(1), 103 ADC12138_VOLTAGE_CHANNEL_DIFF(0, 1, 2), 104 ADC12138_VOLTAGE_CHANNEL_DIFF(1, 0, 3), 105 IIO_CHAN_SOFT_TIMESTAMP(4), 106 }; 107 108 static const struct iio_chan_spec adc12138_channels[] = { 109 ADC12138_VOLTAGE_CHANNEL(0), 110 ADC12138_VOLTAGE_CHANNEL(1), 111 ADC12138_VOLTAGE_CHANNEL(2), 112 ADC12138_VOLTAGE_CHANNEL(3), 113 ADC12138_VOLTAGE_CHANNEL(4), 114 ADC12138_VOLTAGE_CHANNEL(5), 115 ADC12138_VOLTAGE_CHANNEL(6), 116 ADC12138_VOLTAGE_CHANNEL(7), 117 ADC12138_VOLTAGE_CHANNEL_DIFF(0, 1, 8), 118 ADC12138_VOLTAGE_CHANNEL_DIFF(1, 0, 9), 119 ADC12138_VOLTAGE_CHANNEL_DIFF(2, 3, 10), 120 ADC12138_VOLTAGE_CHANNEL_DIFF(3, 2, 11), 121 ADC12138_VOLTAGE_CHANNEL_DIFF(4, 5, 12), 122 ADC12138_VOLTAGE_CHANNEL_DIFF(5, 4, 13), 123 ADC12138_VOLTAGE_CHANNEL_DIFF(6, 7, 14), 124 ADC12138_VOLTAGE_CHANNEL_DIFF(7, 6, 15), 125 IIO_CHAN_SOFT_TIMESTAMP(16), 126 }; 127 128 static int adc12138_mode_programming(struct adc12138 *adc, u8 mode, 129 void *rx_buf, int len) 130 { 131 struct spi_transfer xfer = { 132 .tx_buf = adc->tx_buf, 133 .rx_buf = adc->rx_buf, 134 .len = len, 135 }; 136 int ret; 137 138 /* Skip unused bits for ADC12130 and ADC12132 */ 139 if (adc->id != adc12138) 140 mode = (mode & 0xc0) | ((mode & 0x0f) << 2); 141 142 adc->tx_buf[0] = mode; 143 144 ret = spi_sync_transfer(adc->spi, &xfer, 1); 145 if (ret) 146 return ret; 147 148 memcpy(rx_buf, adc->rx_buf, len); 149 150 return 0; 151 } 152 153 static int adc12138_read_status(struct adc12138 *adc) 154 { 155 u8 rx_buf[2]; 156 int ret; 157 158 ret = adc12138_mode_programming(adc, ADC12138_MODE_READ_STATUS, 159 rx_buf, 2); 160 if (ret) 161 return ret; 162 163 return (rx_buf[0] << 1) | (rx_buf[1] >> 7); 164 } 165 166 static int __adc12138_start_conv(struct adc12138 *adc, 167 struct iio_chan_spec const *channel, 168 void *data, int len) 169 170 { 171 static const u8 ch_to_mux[] = { 0, 4, 1, 5, 2, 6, 3, 7 }; 172 u8 mode = (ch_to_mux[channel->channel] << 4) | 173 (channel->differential ? 0 : 0x80); 174 175 return adc12138_mode_programming(adc, mode, data, len); 176 } 177 178 static int adc12138_start_conv(struct adc12138 *adc, 179 struct iio_chan_spec const *channel) 180 { 181 u8 trash; 182 183 return __adc12138_start_conv(adc, channel, &trash, 1); 184 } 185 186 static int adc12138_start_and_read_conv(struct adc12138 *adc, 187 struct iio_chan_spec const *channel, 188 __be16 *data) 189 { 190 return __adc12138_start_conv(adc, channel, data, 2); 191 } 192 193 static int adc12138_read_conv_data(struct adc12138 *adc, __be16 *value) 194 { 195 /* Issue a read status instruction and read previous conversion data */ 196 return adc12138_mode_programming(adc, ADC12138_MODE_READ_STATUS, 197 value, sizeof(*value)); 198 } 199 200 static int adc12138_wait_eoc(struct adc12138 *adc, unsigned long timeout) 201 { 202 if (!wait_for_completion_timeout(&adc->complete, timeout)) 203 return -ETIMEDOUT; 204 205 return 0; 206 } 207 208 static int adc12138_adc_conversion(struct adc12138 *adc, 209 struct iio_chan_spec const *channel, 210 __be16 *value) 211 { 212 int ret; 213 214 reinit_completion(&adc->complete); 215 216 ret = adc12138_start_conv(adc, channel); 217 if (ret) 218 return ret; 219 220 ret = adc12138_wait_eoc(adc, msecs_to_jiffies(100)); 221 if (ret) 222 return ret; 223 224 return adc12138_read_conv_data(adc, value); 225 } 226 227 static int adc12138_read_raw(struct iio_dev *iio, 228 struct iio_chan_spec const *channel, int *value, 229 int *shift, long mask) 230 { 231 struct adc12138 *adc = iio_priv(iio); 232 int ret; 233 __be16 data; 234 235 switch (mask) { 236 case IIO_CHAN_INFO_RAW: 237 mutex_lock(&adc->lock); 238 ret = adc12138_adc_conversion(adc, channel, &data); 239 mutex_unlock(&adc->lock); 240 if (ret) 241 return ret; 242 243 *value = sign_extend32(be16_to_cpu(data) >> channel->scan_type.shift, 244 channel->scan_type.realbits - 1); 245 246 return IIO_VAL_INT; 247 case IIO_CHAN_INFO_SCALE: 248 ret = regulator_get_voltage(adc->vref_p); 249 if (ret < 0) 250 return ret; 251 *value = ret; 252 253 if (!IS_ERR(adc->vref_n)) { 254 ret = regulator_get_voltage(adc->vref_n); 255 if (ret < 0) 256 return ret; 257 *value -= ret; 258 } 259 260 /* convert regulator output voltage to mV */ 261 *value /= 1000; 262 *shift = channel->scan_type.realbits - 1; 263 264 return IIO_VAL_FRACTIONAL_LOG2; 265 case IIO_CHAN_INFO_OFFSET: 266 if (!IS_ERR(adc->vref_n)) { 267 *value = regulator_get_voltage(adc->vref_n); 268 if (*value < 0) 269 return *value; 270 } else { 271 *value = 0; 272 } 273 274 /* convert regulator output voltage to mV */ 275 *value /= 1000; 276 277 return IIO_VAL_INT; 278 } 279 280 return -EINVAL; 281 } 282 283 static const struct iio_info adc12138_info = { 284 .read_raw = adc12138_read_raw, 285 }; 286 287 static int adc12138_init(struct adc12138 *adc) 288 { 289 int ret; 290 int status; 291 u8 mode; 292 u8 trash; 293 294 reinit_completion(&adc->complete); 295 296 ret = adc12138_mode_programming(adc, ADC12138_MODE_AUTO_CAL, &trash, 1); 297 if (ret) 298 return ret; 299 300 /* data output at this time has no significance */ 301 status = adc12138_read_status(adc); 302 if (status < 0) 303 return status; 304 305 adc12138_wait_eoc(adc, msecs_to_jiffies(100)); 306 307 status = adc12138_read_status(adc); 308 if (status & ADC12138_STATUS_CAL) { 309 dev_warn(&adc->spi->dev, 310 "Auto Cal sequence is still in progress: %#x\n", 311 status); 312 return -EIO; 313 } 314 315 switch (adc->acquisition_time) { 316 case 6: 317 mode = ADC12138_MODE_ACQUISITION_TIME_6; 318 break; 319 case 10: 320 mode = ADC12138_MODE_ACQUISITION_TIME_10; 321 break; 322 case 18: 323 mode = ADC12138_MODE_ACQUISITION_TIME_18; 324 break; 325 case 34: 326 mode = ADC12138_MODE_ACQUISITION_TIME_34; 327 break; 328 default: 329 return -EINVAL; 330 } 331 332 return adc12138_mode_programming(adc, mode, &trash, 1); 333 } 334 335 static irqreturn_t adc12138_trigger_handler(int irq, void *p) 336 { 337 struct iio_poll_func *pf = p; 338 struct iio_dev *indio_dev = pf->indio_dev; 339 struct adc12138 *adc = iio_priv(indio_dev); 340 __be16 trash; 341 int ret; 342 int scan_index; 343 int i = 0; 344 345 mutex_lock(&adc->lock); 346 347 for_each_set_bit(scan_index, indio_dev->active_scan_mask, 348 indio_dev->masklength) { 349 const struct iio_chan_spec *scan_chan = 350 &indio_dev->channels[scan_index]; 351 352 reinit_completion(&adc->complete); 353 354 ret = adc12138_start_and_read_conv(adc, scan_chan, 355 i ? &adc->data[i - 1] : &trash); 356 if (ret) { 357 dev_warn(&adc->spi->dev, 358 "failed to start conversion\n"); 359 goto out; 360 } 361 362 ret = adc12138_wait_eoc(adc, msecs_to_jiffies(100)); 363 if (ret) { 364 dev_warn(&adc->spi->dev, "wait eoc timeout\n"); 365 goto out; 366 } 367 368 i++; 369 } 370 371 if (i) { 372 ret = adc12138_read_conv_data(adc, &adc->data[i - 1]); 373 if (ret) { 374 dev_warn(&adc->spi->dev, 375 "failed to get conversion data\n"); 376 goto out; 377 } 378 } 379 380 iio_push_to_buffers_with_timestamp(indio_dev, adc->data, 381 iio_get_time_ns(indio_dev)); 382 out: 383 mutex_unlock(&adc->lock); 384 385 iio_trigger_notify_done(indio_dev->trig); 386 387 return IRQ_HANDLED; 388 } 389 390 static irqreturn_t adc12138_eoc_handler(int irq, void *p) 391 { 392 struct iio_dev *indio_dev = p; 393 struct adc12138 *adc = iio_priv(indio_dev); 394 395 complete(&adc->complete); 396 397 return IRQ_HANDLED; 398 } 399 400 static int adc12138_probe(struct spi_device *spi) 401 { 402 struct iio_dev *indio_dev; 403 struct adc12138 *adc; 404 int ret; 405 406 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc)); 407 if (!indio_dev) 408 return -ENOMEM; 409 410 adc = iio_priv(indio_dev); 411 adc->spi = spi; 412 adc->id = spi_get_device_id(spi)->driver_data; 413 mutex_init(&adc->lock); 414 init_completion(&adc->complete); 415 416 indio_dev->name = spi_get_device_id(spi)->name; 417 indio_dev->info = &adc12138_info; 418 indio_dev->modes = INDIO_DIRECT_MODE; 419 420 switch (adc->id) { 421 case adc12130: 422 case adc12132: 423 indio_dev->channels = adc12132_channels; 424 indio_dev->num_channels = ARRAY_SIZE(adc12132_channels); 425 break; 426 case adc12138: 427 indio_dev->channels = adc12138_channels; 428 indio_dev->num_channels = ARRAY_SIZE(adc12138_channels); 429 break; 430 default: 431 return -EINVAL; 432 } 433 434 ret = device_property_read_u32(&spi->dev, "ti,acquisition-time", 435 &adc->acquisition_time); 436 if (ret) 437 adc->acquisition_time = 10; 438 439 adc->cclk = devm_clk_get(&spi->dev, NULL); 440 if (IS_ERR(adc->cclk)) 441 return PTR_ERR(adc->cclk); 442 443 adc->vref_p = devm_regulator_get(&spi->dev, "vref-p"); 444 if (IS_ERR(adc->vref_p)) 445 return PTR_ERR(adc->vref_p); 446 447 adc->vref_n = devm_regulator_get_optional(&spi->dev, "vref-n"); 448 if (IS_ERR(adc->vref_n)) { 449 /* 450 * Assume vref_n is 0V if an optional regulator is not 451 * specified, otherwise return the error code. 452 */ 453 ret = PTR_ERR(adc->vref_n); 454 if (ret != -ENODEV) 455 return ret; 456 } 457 458 ret = devm_request_irq(&spi->dev, spi->irq, adc12138_eoc_handler, 459 IRQF_TRIGGER_RISING, indio_dev->name, indio_dev); 460 if (ret) 461 return ret; 462 463 ret = clk_prepare_enable(adc->cclk); 464 if (ret) 465 return ret; 466 467 ret = regulator_enable(adc->vref_p); 468 if (ret) 469 goto err_clk_disable; 470 471 if (!IS_ERR(adc->vref_n)) { 472 ret = regulator_enable(adc->vref_n); 473 if (ret) 474 goto err_vref_p_disable; 475 } 476 477 ret = adc12138_init(adc); 478 if (ret) 479 goto err_vref_n_disable; 480 481 spi_set_drvdata(spi, indio_dev); 482 483 ret = iio_triggered_buffer_setup(indio_dev, NULL, 484 adc12138_trigger_handler, NULL); 485 if (ret) 486 goto err_vref_n_disable; 487 488 ret = iio_device_register(indio_dev); 489 if (ret) 490 goto err_buffer_cleanup; 491 492 return 0; 493 err_buffer_cleanup: 494 iio_triggered_buffer_cleanup(indio_dev); 495 err_vref_n_disable: 496 if (!IS_ERR(adc->vref_n)) 497 regulator_disable(adc->vref_n); 498 err_vref_p_disable: 499 regulator_disable(adc->vref_p); 500 err_clk_disable: 501 clk_disable_unprepare(adc->cclk); 502 503 return ret; 504 } 505 506 static void adc12138_remove(struct spi_device *spi) 507 { 508 struct iio_dev *indio_dev = spi_get_drvdata(spi); 509 struct adc12138 *adc = iio_priv(indio_dev); 510 511 iio_device_unregister(indio_dev); 512 iio_triggered_buffer_cleanup(indio_dev); 513 if (!IS_ERR(adc->vref_n)) 514 regulator_disable(adc->vref_n); 515 regulator_disable(adc->vref_p); 516 clk_disable_unprepare(adc->cclk); 517 } 518 519 static const struct of_device_id adc12138_dt_ids[] = { 520 { .compatible = "ti,adc12130", }, 521 { .compatible = "ti,adc12132", }, 522 { .compatible = "ti,adc12138", }, 523 {} 524 }; 525 MODULE_DEVICE_TABLE(of, adc12138_dt_ids); 526 527 static const struct spi_device_id adc12138_id[] = { 528 { "adc12130", adc12130 }, 529 { "adc12132", adc12132 }, 530 { "adc12138", adc12138 }, 531 {} 532 }; 533 MODULE_DEVICE_TABLE(spi, adc12138_id); 534 535 static struct spi_driver adc12138_driver = { 536 .driver = { 537 .name = "adc12138", 538 .of_match_table = adc12138_dt_ids, 539 }, 540 .probe = adc12138_probe, 541 .remove = adc12138_remove, 542 .id_table = adc12138_id, 543 }; 544 module_spi_driver(adc12138_driver); 545 546 MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>"); 547 MODULE_DESCRIPTION("ADC12130/ADC12132/ADC12138 driver"); 548 MODULE_LICENSE("GPL v2"); 549