drivers/iio/adc/ti-adc12138.c

   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/spi/spi.h>
  15 #include <linux/iio/iio.h>
  16 #include <linux/iio/buffer.h>
  17 #include <linux/iio/trigger.h>
  18 #include <linux/iio/triggered_buffer.h>
  19 #include <linux/iio/trigger_consumer.h>
  20 #include <linux/regulator/consumer.h>
  21
  22 #define ADC12138_MODE_AUTO_CAL                  0x08
  23 #define ADC12138_MODE_READ_STATUS               0x0c
  24 #define ADC12138_MODE_ACQUISITION_TIME_6        0x0e
  25 #define ADC12138_MODE_ACQUISITION_TIME_10       0x4e
  26 #define ADC12138_MODE_ACQUISITION_TIME_18       0x8e
  27 #define ADC12138_MODE_ACQUISITION_TIME_34       0xce
  28
  29 #define ADC12138_STATUS_CAL                     BIT(6)
  30
  31 enum {
  32         adc12130,
  33         adc12132,
  34         adc12138,
  35 };
  36
  37 struct adc12138 {
  38         struct spi_device *spi;
  39         unsigned int id;
  40         /* conversion clock */
  41         struct clk *cclk;
  42         /* positive analog voltage reference */
  43         struct regulator *vref_p;
  44         /* negative analog voltage reference */
  45         struct regulator *vref_n;
  46         struct mutex lock;
  47         struct completion complete;
  48         /* The number of cclk periods for the S/H's acquisition time */
  49         unsigned int acquisition_time;
  50
  51         u8 tx_buf[2] ____cacheline_aligned;
  52         u8 rx_buf[2];
  53 };
  54
  55 #define ADC12138_VOLTAGE_CHANNEL(chan)                                  \
  56         {                                                               \
  57                 .type = IIO_VOLTAGE,                                    \
  58                 .indexed = 1,                                           \
  59                 .channel = chan,                                        \
  60                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
  61                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE)    \
  62                                         | BIT(IIO_CHAN_INFO_OFFSET),    \
  63                 .scan_index = chan,                                     \
  64                 .scan_type = {                                          \
  65                         .sign = 's',                                    \
  66                         .realbits = 13,                                 \
  67                         .storagebits = 16,                              \
  68                         .shift = 3,                                     \
  69                         .endianness = IIO_BE,                           \
  70                 },                                                      \
  71         }
  72
  73 #define ADC12138_VOLTAGE_CHANNEL_DIFF(chan1, chan2, si)                 \
  74         {                                                               \
  75                 .type = IIO_VOLTAGE,                                    \
  76                 .indexed = 1,                                           \
  77                 .channel = (chan1),                                     \
  78                 .channel2 = (chan2),                                    \
  79                 .differential = 1,                                      \
  80                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
  81                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE)    \
  82                                         | BIT(IIO_CHAN_INFO_OFFSET),    \
  83                 .scan_index = si,                                       \
  84                 .scan_type = {                                          \
  85                         .sign = 's',                                    \
  86                         .realbits = 13,                                 \
  87                         .storagebits = 16,                              \
  88                         .shift = 3,                                     \
  89                         .endianness = IIO_BE,                           \
  90                 },                                                      \
  91         }
  92
  93 static const struct iio_chan_spec adc12132_channels[] = {
  94         ADC12138_VOLTAGE_CHANNEL(0),
  95         ADC12138_VOLTAGE_CHANNEL(1),
  96         ADC12138_VOLTAGE_CHANNEL_DIFF(0, 1, 2),
  97         ADC12138_VOLTAGE_CHANNEL_DIFF(1, 0, 3),
  98         IIO_CHAN_SOFT_TIMESTAMP(4),
  99 };
 100
 101 static const struct iio_chan_spec adc12138_channels[] = {
 102         ADC12138_VOLTAGE_CHANNEL(0),
 103         ADC12138_VOLTAGE_CHANNEL(1),
 104         ADC12138_VOLTAGE_CHANNEL(2),
 105         ADC12138_VOLTAGE_CHANNEL(3),
 106         ADC12138_VOLTAGE_CHANNEL(4),
 107         ADC12138_VOLTAGE_CHANNEL(5),
 108         ADC12138_VOLTAGE_CHANNEL(6),
 109         ADC12138_VOLTAGE_CHANNEL(7),
 110         ADC12138_VOLTAGE_CHANNEL_DIFF(0, 1, 8),
 111         ADC12138_VOLTAGE_CHANNEL_DIFF(1, 0, 9),
 112         ADC12138_VOLTAGE_CHANNEL_DIFF(2, 3, 10),
 113         ADC12138_VOLTAGE_CHANNEL_DIFF(3, 2, 11),
 114         ADC12138_VOLTAGE_CHANNEL_DIFF(4, 5, 12),
 115         ADC12138_VOLTAGE_CHANNEL_DIFF(5, 4, 13),
 116         ADC12138_VOLTAGE_CHANNEL_DIFF(6, 7, 14),
 117         ADC12138_VOLTAGE_CHANNEL_DIFF(7, 6, 15),
 118         IIO_CHAN_SOFT_TIMESTAMP(16),
 119 };
 120
 121 static int adc12138_mode_programming(struct adc12138 *adc, u8 mode,
 122                                      void *rx_buf, int len)
 123 {
 124         struct spi_transfer xfer = {
 125                 .tx_buf = adc->tx_buf,
 126                 .rx_buf = adc->rx_buf,
 127                 .len = len,
 128         };
 129         int ret;
 130
 131         /* Skip unused bits for ADC12130 and ADC12132 */
 132         if (adc->id != adc12138)
 133                 mode = (mode & 0xc0) | ((mode & 0x0f) << 2);
 134
 135         adc->tx_buf[0] = mode;
 136
 137         ret = spi_sync_transfer(adc->spi, &xfer, 1);
 138         if (ret)
 139                 return ret;
 140
 141         memcpy(rx_buf, adc->rx_buf, len);
 142
 143         return 0;
 144 }
 145
 146 static int adc12138_read_status(struct adc12138 *adc)
 147 {
 148         u8 rx_buf[2];
 149         int ret;
 150
 151         ret = adc12138_mode_programming(adc, ADC12138_MODE_READ_STATUS,
 152                                         rx_buf, 2);
 153         if (ret)
 154                 return ret;
 155
 156         return (rx_buf[0] << 1) | (rx_buf[1] >> 7);
 157 }
 158
 159 static int __adc12138_start_conv(struct adc12138 *adc,
 160                                  struct iio_chan_spec const *channel,
 161                                  void *data, int len)
 162
 163 {
 164         static const u8 ch_to_mux[] = { 0, 4, 1, 5, 2, 6, 3, 7 };
 165         u8 mode = (ch_to_mux[channel->channel] << 4) |
 166                   (channel->differential ? 0 : 0x80);
 167
 168         return adc12138_mode_programming(adc, mode, data, len);
 169 }
 170
 171 static int adc12138_start_conv(struct adc12138 *adc,
 172                                struct iio_chan_spec const *channel)
 173 {
 174         u8 trash;
 175
 176         return __adc12138_start_conv(adc, channel, &trash, 1);
 177 }
 178
 179 static int adc12138_start_and_read_conv(struct adc12138 *adc,
 180                                         struct iio_chan_spec const *channel,
 181                                         __be16 *data)
 182 {
 183         return __adc12138_start_conv(adc, channel, data, 2);
 184 }
 185
 186 static int adc12138_read_conv_data(struct adc12138 *adc, __be16 *value)
 187 {
 188         /* Issue a read status instruction and read previous conversion data */
 189         return adc12138_mode_programming(adc, ADC12138_MODE_READ_STATUS,
 190                                          value, sizeof(*value));
 191 }
 192
 193 static int adc12138_wait_eoc(struct adc12138 *adc, unsigned long timeout)
 194 {
 195         if (!wait_for_completion_timeout(&adc->complete, timeout))
 196                 return -ETIMEDOUT;
 197
 198         return 0;
 199 }
 200
 201 static int adc12138_adc_conversion(struct adc12138 *adc,
 202                                    struct iio_chan_spec const *channel,
 203                                    __be16 *value)
 204 {
 205         int ret;
 206
 207         reinit_completion(&adc->complete);
 208
 209         ret = adc12138_start_conv(adc, channel);
 210         if (ret)
 211                 return ret;
 212
 213         ret = adc12138_wait_eoc(adc, msecs_to_jiffies(100));
 214         if (ret)
 215                 return ret;
 216
 217         return adc12138_read_conv_data(adc, value);
 218 }
 219
 220 static int adc12138_read_raw(struct iio_dev *iio,
 221                              struct iio_chan_spec const *channel, int *value,
 222                              int *shift, long mask)
 223 {
 224         struct adc12138 *adc = iio_priv(iio);
 225         int ret;
 226         __be16 data;
 227
 228         switch (mask) {
 229         case IIO_CHAN_INFO_RAW:
 230                 mutex_lock(&adc->lock);
 231                 ret = adc12138_adc_conversion(adc, channel, &data);
 232                 mutex_unlock(&adc->lock);
 233                 if (ret)
 234                         return ret;
 235
 236                 *value = sign_extend32(be16_to_cpu(data) >> 3, 12);
 237
 238                 return IIO_VAL_INT;
 239         case IIO_CHAN_INFO_SCALE:
 240                 ret = regulator_get_voltage(adc->vref_p);
 241                 if (ret < 0)
 242                         return ret;
 243                 *value = ret;
 244
 245                 if (!IS_ERR(adc->vref_n)) {
 246                         ret = regulator_get_voltage(adc->vref_n);
 247                         if (ret < 0)
 248                                 return ret;
 249                         *value -= ret;
 250                 }
 251
 252                 /* convert regulator output voltage to mV */
 253                 *value /= 1000;
 254                 *shift = channel->scan_type.realbits - 1;
 255
 256                 return IIO_VAL_FRACTIONAL_LOG2;
 257         case IIO_CHAN_INFO_OFFSET:
 258                 if (!IS_ERR(adc->vref_n)) {
 259                         *value = regulator_get_voltage(adc->vref_n);
 260                         if (*value < 0)
 261                                 return *value;
 262                 } else {
 263                         *value = 0;
 264                 }
 265
 266                 /* convert regulator output voltage to mV */
 267                 *value /= 1000;
 268
 269                 return IIO_VAL_INT;
 270         }
 271
 272         return -EINVAL;
 273 }
 274
 275 static const struct iio_info adc12138_info = {
 276         .read_raw = adc12138_read_raw,
 277 };
 278
 279 static int adc12138_init(struct adc12138 *adc)
 280 {
 281         int ret;
 282         int status;
 283         u8 mode;
 284         u8 trash;
 285
 286         reinit_completion(&adc->complete);
 287
 288         ret = adc12138_mode_programming(adc, ADC12138_MODE_AUTO_CAL, &trash, 1);
 289         if (ret)
 290                 return ret;
 291
 292         /* data output at this time has no significance */
 293         status = adc12138_read_status(adc);
 294         if (status < 0)
 295                 return status;
 296
 297         adc12138_wait_eoc(adc, msecs_to_jiffies(100));
 298
 299         status = adc12138_read_status(adc);
 300         if (status & ADC12138_STATUS_CAL) {
 301                 dev_warn(&adc->spi->dev,
 302                         "Auto Cal sequence is still in progress: %#x\n",
 303                         status);
 304                 return -EIO;
 305         }
 306
 307         switch (adc->acquisition_time) {
 308         case 6:
 309                 mode = ADC12138_MODE_ACQUISITION_TIME_6;
 310                 break;
 311         case 10:
 312                 mode = ADC12138_MODE_ACQUISITION_TIME_10;
 313                 break;
 314         case 18:
 315                 mode = ADC12138_MODE_ACQUISITION_TIME_18;
 316                 break;
 317         case 34:
 318                 mode = ADC12138_MODE_ACQUISITION_TIME_34;
 319                 break;
 320         default:
 321                 return -EINVAL;
 322         }
 323
 324         return adc12138_mode_programming(adc, mode, &trash, 1);
 325 }
 326
 327 static irqreturn_t adc12138_trigger_handler(int irq, void *p)
 328 {
 329         struct iio_poll_func *pf = p;
 330         struct iio_dev *indio_dev = pf->indio_dev;
 331         struct adc12138 *adc = iio_priv(indio_dev);
 332         __be16 data[20] = { }; /* 16x 2 bytes ADC data + 8 bytes timestamp */
 333         __be16 trash;
 334         int ret;
 335         int scan_index;
 336         int i = 0;
 337
 338         mutex_lock(&adc->lock);
 339
 340         for_each_set_bit(scan_index, indio_dev->active_scan_mask,
 341                          indio_dev->masklength) {
 342                 const struct iio_chan_spec *scan_chan =
 343                                 &indio_dev->channels[scan_index];
 344
 345                 reinit_completion(&adc->complete);
 346
 347                 ret = adc12138_start_and_read_conv(adc, scan_chan,
 348                                                    i ? &data[i - 1] : &trash);
 349                 if (ret) {
 350                         dev_warn(&adc->spi->dev,
 351                                  "failed to start conversion\n");
 352                         goto out;
 353                 }
 354
 355                 ret = adc12138_wait_eoc(adc, msecs_to_jiffies(100));
 356                 if (ret) {
 357                         dev_warn(&adc->spi->dev, "wait eoc timeout\n");
 358                         goto out;
 359                 }
 360
 361                 i++;
 362         }
 363
 364         if (i) {
 365                 ret = adc12138_read_conv_data(adc, &data[i - 1]);
 366                 if (ret) {
 367                         dev_warn(&adc->spi->dev,
 368                                  "failed to get conversion data\n");
 369                         goto out;
 370                 }
 371         }
 372
 373         iio_push_to_buffers_with_timestamp(indio_dev, data,
 374                                            iio_get_time_ns(indio_dev));
 375 out:
 376         mutex_unlock(&adc->lock);
 377
 378         iio_trigger_notify_done(indio_dev->trig);
 379
 380         return IRQ_HANDLED;
 381 }
 382
 383 static irqreturn_t adc12138_eoc_handler(int irq, void *p)
 384 {
 385         struct iio_dev *indio_dev = p;
 386         struct adc12138 *adc = iio_priv(indio_dev);
 387
 388         complete(&adc->complete);
 389
 390         return IRQ_HANDLED;
 391 }
 392
 393 static int adc12138_probe(struct spi_device *spi)
 394 {
 395         struct iio_dev *indio_dev;
 396         struct adc12138 *adc;
 397         int ret;
 398
 399         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));
 400         if (!indio_dev)
 401                 return -ENOMEM;
 402
 403         adc = iio_priv(indio_dev);
 404         adc->spi = spi;
 405         adc->id = spi_get_device_id(spi)->driver_data;
 406         mutex_init(&adc->lock);
 407         init_completion(&adc->complete);
 408
 409         indio_dev->name = spi_get_device_id(spi)->name;
 410         indio_dev->dev.parent = &spi->dev;
 411         indio_dev->info = &adc12138_info;
 412         indio_dev->modes = INDIO_DIRECT_MODE;
 413
 414         switch (adc->id) {
 415         case adc12130:
 416         case adc12132:
 417                 indio_dev->channels = adc12132_channels;
 418                 indio_dev->num_channels = ARRAY_SIZE(adc12132_channels);
 419                 break;
 420         case adc12138:
 421                 indio_dev->channels = adc12138_channels;
 422                 indio_dev->num_channels = ARRAY_SIZE(adc12138_channels);
 423                 break;
 424         default:
 425                 return -EINVAL;
 426         }
 427
 428         ret = of_property_read_u32(spi->dev.of_node, "ti,acquisition-time",
 429                                    &adc->acquisition_time);
 430         if (ret)
 431                 adc->acquisition_time = 10;
 432
 433         adc->cclk = devm_clk_get(&spi->dev, NULL);
 434         if (IS_ERR(adc->cclk))
 435                 return PTR_ERR(adc->cclk);
 436
 437         adc->vref_p = devm_regulator_get(&spi->dev, "vref-p");
 438         if (IS_ERR(adc->vref_p))
 439                 return PTR_ERR(adc->vref_p);
 440
 441         adc->vref_n = devm_regulator_get_optional(&spi->dev, "vref-n");
 442         if (IS_ERR(adc->vref_n)) {
 443                 /*
 444                  * Assume vref_n is 0V if an optional regulator is not
 445                  * specified, otherwise return the error code.
 446                  */
 447                 ret = PTR_ERR(adc->vref_n);
 448                 if (ret != -ENODEV)
 449                         return ret;
 450         }
 451
 452         ret = devm_request_irq(&spi->dev, spi->irq, adc12138_eoc_handler,
 453                                IRQF_TRIGGER_RISING, indio_dev->name, indio_dev);
 454         if (ret)
 455                 return ret;
 456
 457         ret = clk_prepare_enable(adc->cclk);
 458         if (ret)
 459                 return ret;
 460
 461         ret = regulator_enable(adc->vref_p);
 462         if (ret)
 463                 goto err_clk_disable;
 464
 465         if (!IS_ERR(adc->vref_n)) {
 466                 ret = regulator_enable(adc->vref_n);
 467                 if (ret)
 468                         goto err_vref_p_disable;
 469         }
 470
 471         ret = adc12138_init(adc);
 472         if (ret)
 473                 goto err_vref_n_disable;
 474
 475         spi_set_drvdata(spi, indio_dev);
 476
 477         ret = iio_triggered_buffer_setup(indio_dev, NULL,
 478                                          adc12138_trigger_handler, NULL);
 479         if (ret)
 480                 goto err_vref_n_disable;
 481
 482         ret = iio_device_register(indio_dev);
 483         if (ret)
 484                 goto err_buffer_cleanup;
 485
 486         return 0;
 487 err_buffer_cleanup:
 488         iio_triggered_buffer_cleanup(indio_dev);
 489 err_vref_n_disable:
 490         if (!IS_ERR(adc->vref_n))
 491                 regulator_disable(adc->vref_n);
 492 err_vref_p_disable:
 493         regulator_disable(adc->vref_p);
 494 err_clk_disable:
 495         clk_disable_unprepare(adc->cclk);
 496
 497         return ret;
 498 }
 499
 500 static int adc12138_remove(struct spi_device *spi)
 501 {
 502         struct iio_dev *indio_dev = spi_get_drvdata(spi);
 503         struct adc12138 *adc = iio_priv(indio_dev);
 504
 505         iio_device_unregister(indio_dev);
 506         iio_triggered_buffer_cleanup(indio_dev);
 507         if (!IS_ERR(adc->vref_n))
 508                 regulator_disable(adc->vref_n);
 509         regulator_disable(adc->vref_p);
 510         clk_disable_unprepare(adc->cclk);
 511
 512         return 0;
 513 }
 514
 515 #ifdef CONFIG_OF
 516
 517 static const struct of_device_id adc12138_dt_ids[] = {
 518         { .compatible = "ti,adc12130", },
 519         { .compatible = "ti,adc12132", },
 520         { .compatible = "ti,adc12138", },
 521         {}
 522 };
 523 MODULE_DEVICE_TABLE(of, adc12138_dt_ids);
 524
 525 #endif
 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 = of_match_ptr(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");