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          * Maximum size needed: 16x 2 bytes ADC data + 8 bytes timestamp.
  52          * Less may be need if not all channels are enabled, as long as
  53          * the 8 byte alignment of the timestamp is maintained.
  54          */
  55         __be16 data[20] __aligned(8);
  56
  57         u8 tx_buf[2] ____cacheline_aligned;
  58         u8 rx_buf[2];
  59 };
  60
  61 #define ADC12138_VOLTAGE_CHANNEL(chan)                                  \
  62         {                                                               \
  63                 .type = IIO_VOLTAGE,                                    \
  64                 .indexed = 1,                                           \
  65                 .channel = chan,                                        \
  66                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
  67                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE)    \
  68                                         | BIT(IIO_CHAN_INFO_OFFSET),    \
  69                 .scan_index = chan,                                     \
  70                 .scan_type = {                                          \
  71                         .sign = 's',                                    \
  72                         .realbits = 13,                                 \
  73                         .storagebits = 16,                              \
  74                         .shift = 3,                                     \
  75                         .endianness = IIO_BE,                           \
  76                 },                                                      \
  77         }
  78
  79 #define ADC12138_VOLTAGE_CHANNEL_DIFF(chan1, chan2, si)                 \
  80         {                                                               \
  81                 .type = IIO_VOLTAGE,                                    \
  82                 .indexed = 1,                                           \
  83                 .channel = (chan1),                                     \
  84                 .channel2 = (chan2),                                    \
  85                 .differential = 1,                                      \
  86                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
  87                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE)    \
  88                                         | BIT(IIO_CHAN_INFO_OFFSET),    \
  89                 .scan_index = si,                                       \
  90                 .scan_type = {                                          \
  91                         .sign = 's',                                    \
  92                         .realbits = 13,                                 \
  93                         .storagebits = 16,                              \
  94                         .shift = 3,                                     \
  95                         .endianness = IIO_BE,                           \
  96                 },                                                      \
  97         }
  98
  99 static const struct iio_chan_spec adc12132_channels[] = {
 100         ADC12138_VOLTAGE_CHANNEL(0),
 101         ADC12138_VOLTAGE_CHANNEL(1),
 102         ADC12138_VOLTAGE_CHANNEL_DIFF(0, 1, 2),
 103         ADC12138_VOLTAGE_CHANNEL_DIFF(1, 0, 3),
 104         IIO_CHAN_SOFT_TIMESTAMP(4),
 105 };
 106
 107 static const struct iio_chan_spec adc12138_channels[] = {
 108         ADC12138_VOLTAGE_CHANNEL(0),
 109         ADC12138_VOLTAGE_CHANNEL(1),
 110         ADC12138_VOLTAGE_CHANNEL(2),
 111         ADC12138_VOLTAGE_CHANNEL(3),
 112         ADC12138_VOLTAGE_CHANNEL(4),
 113         ADC12138_VOLTAGE_CHANNEL(5),
 114         ADC12138_VOLTAGE_CHANNEL(6),
 115         ADC12138_VOLTAGE_CHANNEL(7),
 116         ADC12138_VOLTAGE_CHANNEL_DIFF(0, 1, 8),
 117         ADC12138_VOLTAGE_CHANNEL_DIFF(1, 0, 9),
 118         ADC12138_VOLTAGE_CHANNEL_DIFF(2, 3, 10),
 119         ADC12138_VOLTAGE_CHANNEL_DIFF(3, 2, 11),
 120         ADC12138_VOLTAGE_CHANNEL_DIFF(4, 5, 12),
 121         ADC12138_VOLTAGE_CHANNEL_DIFF(5, 4, 13),
 122         ADC12138_VOLTAGE_CHANNEL_DIFF(6, 7, 14),
 123         ADC12138_VOLTAGE_CHANNEL_DIFF(7, 6, 15),
 124         IIO_CHAN_SOFT_TIMESTAMP(16),
 125 };
 126
 127 static int adc12138_mode_programming(struct adc12138 *adc, u8 mode,
 128                                      void *rx_buf, int len)
 129 {
 130         struct spi_transfer xfer = {
 131                 .tx_buf = adc->tx_buf,
 132                 .rx_buf = adc->rx_buf,
 133                 .len = len,
 134         };
 135         int ret;
 136
 137         /* Skip unused bits for ADC12130 and ADC12132 */
 138         if (adc->id != adc12138)
 139                 mode = (mode & 0xc0) | ((mode & 0x0f) << 2);
 140
 141         adc->tx_buf[0] = mode;
 142
 143         ret = spi_sync_transfer(adc->spi, &xfer, 1);
 144         if (ret)
 145                 return ret;
 146
 147         memcpy(rx_buf, adc->rx_buf, len);
 148
 149         return 0;
 150 }
 151
 152 static int adc12138_read_status(struct adc12138 *adc)
 153 {
 154         u8 rx_buf[2];
 155         int ret;
 156
 157         ret = adc12138_mode_programming(adc, ADC12138_MODE_READ_STATUS,
 158                                         rx_buf, 2);
 159         if (ret)
 160                 return ret;
 161
 162         return (rx_buf[0] << 1) | (rx_buf[1] >> 7);
 163 }
 164
 165 static int __adc12138_start_conv(struct adc12138 *adc,
 166                                  struct iio_chan_spec const *channel,
 167                                  void *data, int len)
 168
 169 {
 170         static const u8 ch_to_mux[] = { 0, 4, 1, 5, 2, 6, 3, 7 };
 171         u8 mode = (ch_to_mux[channel->channel] << 4) |
 172                   (channel->differential ? 0 : 0x80);
 173
 174         return adc12138_mode_programming(adc, mode, data, len);
 175 }
 176
 177 static int adc12138_start_conv(struct adc12138 *adc,
 178                                struct iio_chan_spec const *channel)
 179 {
 180         u8 trash;
 181
 182         return __adc12138_start_conv(adc, channel, &trash, 1);
 183 }
 184
 185 static int adc12138_start_and_read_conv(struct adc12138 *adc,
 186                                         struct iio_chan_spec const *channel,
 187                                         __be16 *data)
 188 {
 189         return __adc12138_start_conv(adc, channel, data, 2);
 190 }
 191
 192 static int adc12138_read_conv_data(struct adc12138 *adc, __be16 *value)
 193 {
 194         /* Issue a read status instruction and read previous conversion data */
 195         return adc12138_mode_programming(adc, ADC12138_MODE_READ_STATUS,
 196                                          value, sizeof(*value));
 197 }
 198
 199 static int adc12138_wait_eoc(struct adc12138 *adc, unsigned long timeout)
 200 {
 201         if (!wait_for_completion_timeout(&adc->complete, timeout))
 202                 return -ETIMEDOUT;
 203
 204         return 0;
 205 }
 206
 207 static int adc12138_adc_conversion(struct adc12138 *adc,
 208                                    struct iio_chan_spec const *channel,
 209                                    __be16 *value)
 210 {
 211         int ret;
 212
 213         reinit_completion(&adc->complete);
 214
 215         ret = adc12138_start_conv(adc, channel);
 216         if (ret)
 217                 return ret;
 218
 219         ret = adc12138_wait_eoc(adc, msecs_to_jiffies(100));
 220         if (ret)
 221                 return ret;
 222
 223         return adc12138_read_conv_data(adc, value);
 224 }
 225
 226 static int adc12138_read_raw(struct iio_dev *iio,
 227                              struct iio_chan_spec const *channel, int *value,
 228                              int *shift, long mask)
 229 {
 230         struct adc12138 *adc = iio_priv(iio);
 231         int ret;
 232         __be16 data;
 233
 234         switch (mask) {
 235         case IIO_CHAN_INFO_RAW:
 236                 mutex_lock(&adc->lock);
 237                 ret = adc12138_adc_conversion(adc, channel, &data);
 238                 mutex_unlock(&adc->lock);
 239                 if (ret)
 240                         return ret;
 241
 242                 *value = sign_extend32(be16_to_cpu(data) >> 3, 12);
 243
 244                 return IIO_VAL_INT;
 245         case IIO_CHAN_INFO_SCALE:
 246                 ret = regulator_get_voltage(adc->vref_p);
 247                 if (ret < 0)
 248                         return ret;
 249                 *value = ret;
 250
 251                 if (!IS_ERR(adc->vref_n)) {
 252                         ret = regulator_get_voltage(adc->vref_n);
 253                         if (ret < 0)
 254                                 return ret;
 255                         *value -= ret;
 256                 }
 257
 258                 /* convert regulator output voltage to mV */
 259                 *value /= 1000;
 260                 *shift = channel->scan_type.realbits - 1;
 261
 262                 return IIO_VAL_FRACTIONAL_LOG2;
 263         case IIO_CHAN_INFO_OFFSET:
 264                 if (!IS_ERR(adc->vref_n)) {
 265                         *value = regulator_get_voltage(adc->vref_n);
 266                         if (*value < 0)
 267                                 return *value;
 268                 } else {
 269                         *value = 0;
 270                 }
 271
 272                 /* convert regulator output voltage to mV */
 273                 *value /= 1000;
 274
 275                 return IIO_VAL_INT;
 276         }
 277
 278         return -EINVAL;
 279 }
 280
 281 static const struct iio_info adc12138_info = {
 282         .read_raw = adc12138_read_raw,
 283 };
 284
 285 static int adc12138_init(struct adc12138 *adc)
 286 {
 287         int ret;
 288         int status;
 289         u8 mode;
 290         u8 trash;
 291
 292         reinit_completion(&adc->complete);
 293
 294         ret = adc12138_mode_programming(adc, ADC12138_MODE_AUTO_CAL, &trash, 1);
 295         if (ret)
 296                 return ret;
 297
 298         /* data output at this time has no significance */
 299         status = adc12138_read_status(adc);
 300         if (status < 0)
 301                 return status;
 302
 303         adc12138_wait_eoc(adc, msecs_to_jiffies(100));
 304
 305         status = adc12138_read_status(adc);
 306         if (status & ADC12138_STATUS_CAL) {
 307                 dev_warn(&adc->spi->dev,
 308                         "Auto Cal sequence is still in progress: %#x\n",
 309                         status);
 310                 return -EIO;
 311         }
 312
 313         switch (adc->acquisition_time) {
 314         case 6:
 315                 mode = ADC12138_MODE_ACQUISITION_TIME_6;
 316                 break;
 317         case 10:
 318                 mode = ADC12138_MODE_ACQUISITION_TIME_10;
 319                 break;
 320         case 18:
 321                 mode = ADC12138_MODE_ACQUISITION_TIME_18;
 322                 break;
 323         case 34:
 324                 mode = ADC12138_MODE_ACQUISITION_TIME_34;
 325                 break;
 326         default:
 327                 return -EINVAL;
 328         }
 329
 330         return adc12138_mode_programming(adc, mode, &trash, 1);
 331 }
 332
 333 static irqreturn_t adc12138_trigger_handler(int irq, void *p)
 334 {
 335         struct iio_poll_func *pf = p;
 336         struct iio_dev *indio_dev = pf->indio_dev;
 337         struct adc12138 *adc = iio_priv(indio_dev);
 338         __be16 trash;
 339         int ret;
 340         int scan_index;
 341         int i = 0;
 342
 343         mutex_lock(&adc->lock);
 344
 345         for_each_set_bit(scan_index, indio_dev->active_scan_mask,
 346                          indio_dev->masklength) {
 347                 const struct iio_chan_spec *scan_chan =
 348                                 &indio_dev->channels[scan_index];
 349
 350                 reinit_completion(&adc->complete);
 351
 352                 ret = adc12138_start_and_read_conv(adc, scan_chan,
 353                                         i ? &adc->data[i - 1] : &trash);
 354                 if (ret) {
 355                         dev_warn(&adc->spi->dev,
 356                                  "failed to start conversion\n");
 357                         goto out;
 358                 }
 359
 360                 ret = adc12138_wait_eoc(adc, msecs_to_jiffies(100));
 361                 if (ret) {
 362                         dev_warn(&adc->spi->dev, "wait eoc timeout\n");
 363                         goto out;
 364                 }
 365
 366                 i++;
 367         }
 368
 369         if (i) {
 370                 ret = adc12138_read_conv_data(adc, &adc->data[i - 1]);
 371                 if (ret) {
 372                         dev_warn(&adc->spi->dev,
 373                                  "failed to get conversion data\n");
 374                         goto out;
 375                 }
 376         }
 377
 378         iio_push_to_buffers_with_timestamp(indio_dev, adc->data,
 379                                            iio_get_time_ns(indio_dev));
 380 out:
 381         mutex_unlock(&adc->lock);
 382
 383         iio_trigger_notify_done(indio_dev->trig);
 384
 385         return IRQ_HANDLED;
 386 }
 387
 388 static irqreturn_t adc12138_eoc_handler(int irq, void *p)
 389 {
 390         struct iio_dev *indio_dev = p;
 391         struct adc12138 *adc = iio_priv(indio_dev);
 392
 393         complete(&adc->complete);
 394
 395         return IRQ_HANDLED;
 396 }
 397
 398 static int adc12138_probe(struct spi_device *spi)
 399 {
 400         struct iio_dev *indio_dev;
 401         struct adc12138 *adc;
 402         int ret;
 403
 404         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));
 405         if (!indio_dev)
 406                 return -ENOMEM;
 407
 408         adc = iio_priv(indio_dev);
 409         adc->spi = spi;
 410         adc->id = spi_get_device_id(spi)->driver_data;
 411         mutex_init(&adc->lock);
 412         init_completion(&adc->complete);
 413
 414         indio_dev->name = spi_get_device_id(spi)->name;
 415         indio_dev->info = &adc12138_info;
 416         indio_dev->modes = INDIO_DIRECT_MODE;
 417
 418         switch (adc->id) {
 419         case adc12130:
 420         case adc12132:
 421                 indio_dev->channels = adc12132_channels;
 422                 indio_dev->num_channels = ARRAY_SIZE(adc12132_channels);
 423                 break;
 424         case adc12138:
 425                 indio_dev->channels = adc12138_channels;
 426                 indio_dev->num_channels = ARRAY_SIZE(adc12138_channels);
 427                 break;
 428         default:
 429                 return -EINVAL;
 430         }
 431
 432         ret = of_property_read_u32(spi->dev.of_node, "ti,acquisition-time",
 433                                    &adc->acquisition_time);
 434         if (ret)
 435                 adc->acquisition_time = 10;
 436
 437         adc->cclk = devm_clk_get(&spi->dev, NULL);
 438         if (IS_ERR(adc->cclk))
 439                 return PTR_ERR(adc->cclk);
 440
 441         adc->vref_p = devm_regulator_get(&spi->dev, "vref-p");
 442         if (IS_ERR(adc->vref_p))
 443                 return PTR_ERR(adc->vref_p);
 444
 445         adc->vref_n = devm_regulator_get_optional(&spi->dev, "vref-n");
 446         if (IS_ERR(adc->vref_n)) {
 447                 /*
 448                  * Assume vref_n is 0V if an optional regulator is not
 449                  * specified, otherwise return the error code.
 450                  */
 451                 ret = PTR_ERR(adc->vref_n);
 452                 if (ret != -ENODEV)
 453                         return ret;
 454         }
 455
 456         ret = devm_request_irq(&spi->dev, spi->irq, adc12138_eoc_handler,
 457                                IRQF_TRIGGER_RISING, indio_dev->name, indio_dev);
 458         if (ret)
 459                 return ret;
 460
 461         ret = clk_prepare_enable(adc->cclk);
 462         if (ret)
 463                 return ret;
 464
 465         ret = regulator_enable(adc->vref_p);
 466         if (ret)
 467                 goto err_clk_disable;
 468
 469         if (!IS_ERR(adc->vref_n)) {
 470                 ret = regulator_enable(adc->vref_n);
 471                 if (ret)
 472                         goto err_vref_p_disable;
 473         }
 474
 475         ret = adc12138_init(adc);
 476         if (ret)
 477                 goto err_vref_n_disable;
 478
 479         spi_set_drvdata(spi, indio_dev);
 480
 481         ret = iio_triggered_buffer_setup(indio_dev, NULL,
 482                                          adc12138_trigger_handler, NULL);
 483         if (ret)
 484                 goto err_vref_n_disable;
 485
 486         ret = iio_device_register(indio_dev);
 487         if (ret)
 488                 goto err_buffer_cleanup;
 489
 490         return 0;
 491 err_buffer_cleanup:
 492         iio_triggered_buffer_cleanup(indio_dev);
 493 err_vref_n_disable:
 494         if (!IS_ERR(adc->vref_n))
 495                 regulator_disable(adc->vref_n);
 496 err_vref_p_disable:
 497         regulator_disable(adc->vref_p);
 498 err_clk_disable:
 499         clk_disable_unprepare(adc->cclk);
 500
 501         return ret;
 502 }
 503
 504 static int adc12138_remove(struct spi_device *spi)
 505 {
 506         struct iio_dev *indio_dev = spi_get_drvdata(spi);
 507         struct adc12138 *adc = iio_priv(indio_dev);
 508
 509         iio_device_unregister(indio_dev);
 510         iio_triggered_buffer_cleanup(indio_dev);
 511         if (!IS_ERR(adc->vref_n))
 512                 regulator_disable(adc->vref_n);
 513         regulator_disable(adc->vref_p);
 514         clk_disable_unprepare(adc->cclk);
 515
 516         return 0;
 517 }
 518
 519 #ifdef CONFIG_OF
 520
 521 static const struct of_device_id adc12138_dt_ids[] = {
 522         { .compatible = "ti,adc12130", },
 523         { .compatible = "ti,adc12132", },
 524         { .compatible = "ti,adc12138", },
 525         {}
 526 };
 527 MODULE_DEVICE_TABLE(of, adc12138_dt_ids);
 528
 529 #endif
 530
 531 static const struct spi_device_id adc12138_id[] = {
 532         { "adc12130", adc12130 },
 533         { "adc12132", adc12132 },
 534         { "adc12138", adc12138 },
 535         {}
 536 };
 537 MODULE_DEVICE_TABLE(spi, adc12138_id);
 538
 539 static struct spi_driver adc12138_driver = {
 540         .driver = {
 541                 .name = "adc12138",
 542                 .of_match_table = of_match_ptr(adc12138_dt_ids),
 543         },
 544         .probe = adc12138_probe,
 545         .remove = adc12138_remove,
 546         .id_table = adc12138_id,
 547 };
 548 module_spi_driver(adc12138_driver);
 549
 550 MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>");
 551 MODULE_DESCRIPTION("ADC12130/ADC12132/ADC12138 driver");
 552 MODULE_LICENSE("GPL v2");