drivers/iio/adc/ti-adc12138.c

   1 /*
   2  * ADC12130/ADC12132/ADC12138 12-bit plus sign ADC driver
   3  *
   4  * Copyright (c) 2016 Akinobu Mita <akinobu.mita@gmail.com>
   5  *
   6  * This file is subject to the terms and conditions of version 2 of
   7  * the GNU General Public License.  See the file COPYING in the main
   8  * directory of this archive for more details.
   9  *
  10  * Datasheet: http://www.ti.com/lit/ds/symlink/adc12138.pdf
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/completion.h>
  16 #include <linux/clk.h>
  17 #include <linux/spi/spi.h>
  18 #include <linux/iio/iio.h>
  19 #include <linux/iio/buffer.h>
  20 #include <linux/iio/trigger.h>
  21 #include <linux/iio/triggered_buffer.h>
  22 #include <linux/iio/trigger_consumer.h>
  23 #include <linux/regulator/consumer.h>
  24
  25 #define ADC12138_MODE_AUTO_CAL                  0x08
  26 #define ADC12138_MODE_READ_STATUS               0x0c
  27 #define ADC12138_MODE_ACQUISITION_TIME_6        0x0e
  28 #define ADC12138_MODE_ACQUISITION_TIME_10       0x4e
  29 #define ADC12138_MODE_ACQUISITION_TIME_18       0x8e
  30 #define ADC12138_MODE_ACQUISITION_TIME_34       0xce
  31
  32 #define ADC12138_STATUS_CAL                     BIT(6)
  33
  34 enum {
  35         adc12130,
  36         adc12132,
  37         adc12138,
  38 };
  39
  40 struct adc12138 {
  41         struct spi_device *spi;
  42         unsigned int id;
  43         /* conversion clock */
  44         struct clk *cclk;
  45         /* positive analog voltage reference */
  46         struct regulator *vref_p;
  47         /* negative analog voltage reference */
  48         struct regulator *vref_n;
  49         struct mutex lock;
  50         struct completion complete;
  51         /* The number of cclk periods for the S/H's acquisition time */
  52         unsigned int acquisition_time;
  53
  54         u8 tx_buf[2] ____cacheline_aligned;
  55         u8 rx_buf[2];
  56 };
  57
  58 #define ADC12138_VOLTAGE_CHANNEL(chan)                                  \
  59         {                                                               \
  60                 .type = IIO_VOLTAGE,                                    \
  61                 .indexed = 1,                                           \
  62                 .channel = chan,                                        \
  63                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
  64                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE)    \
  65                                         | BIT(IIO_CHAN_INFO_OFFSET),    \
  66                 .scan_index = chan,                                     \
  67                 .scan_type = {                                          \
  68                         .sign = 's',                                    \
  69                         .realbits = 13,                                 \
  70                         .storagebits = 16,                              \
  71                         .shift = 3,                                     \
  72                         .endianness = IIO_BE,                           \
  73                 },                                                      \
  74         }
  75
  76 #define ADC12138_VOLTAGE_CHANNEL_DIFF(chan1, chan2, si)                 \
  77         {                                                               \
  78                 .type = IIO_VOLTAGE,                                    \
  79                 .indexed = 1,                                           \
  80                 .channel = (chan1),                                     \
  81                 .channel2 = (chan2),                                    \
  82                 .differential = 1,                                      \
  83                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
  84                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE)    \
  85                                         | BIT(IIO_CHAN_INFO_OFFSET),    \
  86                 .scan_index = si,                                       \
  87                 .scan_type = {                                          \
  88                         .sign = 's',                                    \
  89                         .realbits = 13,                                 \
  90                         .storagebits = 16,                              \
  91                         .shift = 3,                                     \
  92                         .endianness = IIO_BE,                           \
  93                 },                                                      \
  94         }
  95
  96 static const struct iio_chan_spec adc12132_channels[] = {
  97         ADC12138_VOLTAGE_CHANNEL(0),
  98         ADC12138_VOLTAGE_CHANNEL(1),
  99         ADC12138_VOLTAGE_CHANNEL_DIFF(0, 1, 2),
 100         ADC12138_VOLTAGE_CHANNEL_DIFF(1, 0, 3),
 101         IIO_CHAN_SOFT_TIMESTAMP(4),
 102 };
 103
 104 static const struct iio_chan_spec adc12138_channels[] = {
 105         ADC12138_VOLTAGE_CHANNEL(0),
 106         ADC12138_VOLTAGE_CHANNEL(1),
 107         ADC12138_VOLTAGE_CHANNEL(2),
 108         ADC12138_VOLTAGE_CHANNEL(3),
 109         ADC12138_VOLTAGE_CHANNEL(4),
 110         ADC12138_VOLTAGE_CHANNEL(5),
 111         ADC12138_VOLTAGE_CHANNEL(6),
 112         ADC12138_VOLTAGE_CHANNEL(7),
 113         ADC12138_VOLTAGE_CHANNEL_DIFF(0, 1, 8),
 114         ADC12138_VOLTAGE_CHANNEL_DIFF(1, 0, 9),
 115         ADC12138_VOLTAGE_CHANNEL_DIFF(2, 3, 10),
 116         ADC12138_VOLTAGE_CHANNEL_DIFF(3, 2, 11),
 117         ADC12138_VOLTAGE_CHANNEL_DIFF(4, 5, 12),
 118         ADC12138_VOLTAGE_CHANNEL_DIFF(5, 4, 13),
 119         ADC12138_VOLTAGE_CHANNEL_DIFF(6, 7, 14),
 120         ADC12138_VOLTAGE_CHANNEL_DIFF(7, 6, 15),
 121         IIO_CHAN_SOFT_TIMESTAMP(16),
 122 };
 123
 124 static int adc12138_mode_programming(struct adc12138 *adc, u8 mode,
 125                                      void *rx_buf, int len)
 126 {
 127         struct spi_transfer xfer = {
 128                 .tx_buf = adc->tx_buf,
 129                 .rx_buf = adc->rx_buf,
 130                 .len = len,
 131         };
 132         int ret;
 133
 134         /* Skip unused bits for ADC12130 and ADC12132 */
 135         if (adc->id != adc12138)
 136                 mode = (mode & 0xc0) | ((mode & 0x0f) << 2);
 137
 138         adc->tx_buf[0] = mode;
 139
 140         ret = spi_sync_transfer(adc->spi, &xfer, 1);
 141         if (ret)
 142                 return ret;
 143
 144         memcpy(rx_buf, adc->rx_buf, len);
 145
 146         return 0;
 147 }
 148
 149 static int adc12138_read_status(struct adc12138 *adc)
 150 {
 151         u8 rx_buf[2];
 152         int ret;
 153
 154         ret = adc12138_mode_programming(adc, ADC12138_MODE_READ_STATUS,
 155                                         rx_buf, 2);
 156         if (ret)
 157                 return ret;
 158
 159         return (rx_buf[0] << 1) | (rx_buf[1] >> 7);
 160 }
 161
 162 static int __adc12138_start_conv(struct adc12138 *adc,
 163                                  struct iio_chan_spec const *channel,
 164                                  void *data, int len)
 165
 166 {
 167         static const u8 ch_to_mux[] = { 0, 4, 1, 5, 2, 6, 3, 7 };
 168         u8 mode = (ch_to_mux[channel->channel] << 4) |
 169                   (channel->differential ? 0 : 0x80);
 170
 171         return adc12138_mode_programming(adc, mode, data, len);
 172 }
 173
 174 static int adc12138_start_conv(struct adc12138 *adc,
 175                                struct iio_chan_spec const *channel)
 176 {
 177         u8 trash;
 178
 179         return __adc12138_start_conv(adc, channel, &trash, 1);
 180 }
 181
 182 static int adc12138_start_and_read_conv(struct adc12138 *adc,
 183                                         struct iio_chan_spec const *channel,
 184                                         __be16 *data)
 185 {
 186         return __adc12138_start_conv(adc, channel, data, 2);
 187 }
 188
 189 static int adc12138_read_conv_data(struct adc12138 *adc, __be16 *value)
 190 {
 191         /* Issue a read status instruction and read previous conversion data */
 192         return adc12138_mode_programming(adc, ADC12138_MODE_READ_STATUS,
 193                                          value, sizeof(*value));
 194 }
 195
 196 static int adc12138_wait_eoc(struct adc12138 *adc, unsigned long timeout)
 197 {
 198         if (!wait_for_completion_timeout(&adc->complete, timeout))
 199                 return -ETIMEDOUT;
 200
 201         return 0;
 202 }
 203
 204 static int adc12138_adc_conversion(struct adc12138 *adc,
 205                                    struct iio_chan_spec const *channel,
 206                                    __be16 *value)
 207 {
 208         int ret;
 209
 210         reinit_completion(&adc->complete);
 211
 212         ret = adc12138_start_conv(adc, channel);
 213         if (ret)
 214                 return ret;
 215
 216         ret = adc12138_wait_eoc(adc, msecs_to_jiffies(100));
 217         if (ret)
 218                 return ret;
 219
 220         return adc12138_read_conv_data(adc, value);
 221 }
 222
 223 static int adc12138_read_raw(struct iio_dev *iio,
 224                              struct iio_chan_spec const *channel, int *value,
 225                              int *shift, long mask)
 226 {
 227         struct adc12138 *adc = iio_priv(iio);
 228         int ret;
 229         __be16 data;
 230
 231         switch (mask) {
 232         case IIO_CHAN_INFO_RAW:
 233                 mutex_lock(&adc->lock);
 234                 ret = adc12138_adc_conversion(adc, channel, &data);
 235                 mutex_unlock(&adc->lock);
 236                 if (ret)
 237                         return ret;
 238
 239                 *value = sign_extend32(be16_to_cpu(data) >> 3, 12);
 240
 241                 return IIO_VAL_INT;
 242         case IIO_CHAN_INFO_SCALE:
 243                 ret = regulator_get_voltage(adc->vref_p);
 244                 if (ret < 0)
 245                         return ret;
 246                 *value = ret;
 247
 248                 if (!IS_ERR(adc->vref_n)) {
 249                         ret = regulator_get_voltage(adc->vref_n);
 250                         if (ret < 0)
 251                                 return ret;
 252                         *value -= ret;
 253                 }
 254
 255                 /* convert regulator output voltage to mV */
 256                 *value /= 1000;
 257                 *shift = channel->scan_type.realbits - 1;
 258
 259                 return IIO_VAL_FRACTIONAL_LOG2;
 260         case IIO_CHAN_INFO_OFFSET:
 261                 if (!IS_ERR(adc->vref_n)) {
 262                         *value = regulator_get_voltage(adc->vref_n);
 263                         if (*value < 0)
 264                                 return *value;
 265                 } else {
 266                         *value = 0;
 267                 }
 268
 269                 /* convert regulator output voltage to mV */
 270                 *value /= 1000;
 271
 272                 return IIO_VAL_INT;
 273         }
 274
 275         return -EINVAL;
 276 }
 277
 278 static const struct iio_info adc12138_info = {
 279         .read_raw = adc12138_read_raw,
 280 };
 281
 282 static int adc12138_init(struct adc12138 *adc)
 283 {
 284         int ret;
 285         int status;
 286         u8 mode;
 287         u8 trash;
 288
 289         reinit_completion(&adc->complete);
 290
 291         ret = adc12138_mode_programming(adc, ADC12138_MODE_AUTO_CAL, &trash, 1);
 292         if (ret)
 293                 return ret;
 294
 295         /* data output at this time has no significance */
 296         status = adc12138_read_status(adc);
 297         if (status < 0)
 298                 return status;
 299
 300         adc12138_wait_eoc(adc, msecs_to_jiffies(100));
 301
 302         status = adc12138_read_status(adc);
 303         if (status & ADC12138_STATUS_CAL) {
 304                 dev_warn(&adc->spi->dev,
 305                         "Auto Cal sequence is still in progress: %#x\n",
 306                         status);
 307                 return -EIO;
 308         }
 309
 310         switch (adc->acquisition_time) {
 311         case 6:
 312                 mode = ADC12138_MODE_ACQUISITION_TIME_6;
 313                 break;
 314         case 10:
 315                 mode = ADC12138_MODE_ACQUISITION_TIME_10;
 316                 break;
 317         case 18:
 318                 mode = ADC12138_MODE_ACQUISITION_TIME_18;
 319                 break;
 320         case 34:
 321                 mode = ADC12138_MODE_ACQUISITION_TIME_34;
 322                 break;
 323         default:
 324                 return -EINVAL;
 325         }
 326
 327         return adc12138_mode_programming(adc, mode, &trash, 1);
 328 }
 329
 330 static irqreturn_t adc12138_trigger_handler(int irq, void *p)
 331 {
 332         struct iio_poll_func *pf = p;
 333         struct iio_dev *indio_dev = pf->indio_dev;
 334         struct adc12138 *adc = iio_priv(indio_dev);
 335         __be16 data[20] = { }; /* 16x 2 bytes ADC data + 8 bytes timestamp */
 336         __be16 trash;
 337         int ret;
 338         int scan_index;
 339         int i = 0;
 340
 341         mutex_lock(&adc->lock);
 342
 343         for_each_set_bit(scan_index, indio_dev->active_scan_mask,
 344                          indio_dev->masklength) {
 345                 const struct iio_chan_spec *scan_chan =
 346                                 &indio_dev->channels[scan_index];
 347
 348                 reinit_completion(&adc->complete);
 349
 350                 ret = adc12138_start_and_read_conv(adc, scan_chan,
 351                                                    i ? &data[i - 1] : &trash);
 352                 if (ret) {
 353                         dev_warn(&adc->spi->dev,
 354                                  "failed to start conversion\n");
 355                         goto out;
 356                 }
 357
 358                 ret = adc12138_wait_eoc(adc, msecs_to_jiffies(100));
 359                 if (ret) {
 360                         dev_warn(&adc->spi->dev, "wait eoc timeout\n");
 361                         goto out;
 362                 }
 363
 364                 i++;
 365         }
 366
 367         if (i) {
 368                 ret = adc12138_read_conv_data(adc, &data[i - 1]);
 369                 if (ret) {
 370                         dev_warn(&adc->spi->dev,
 371                                  "failed to get conversion data\n");
 372                         goto out;
 373                 }
 374         }
 375
 376         iio_push_to_buffers_with_timestamp(indio_dev, data,
 377                                            iio_get_time_ns(indio_dev));
 378 out:
 379         mutex_unlock(&adc->lock);
 380
 381         iio_trigger_notify_done(indio_dev->trig);
 382
 383         return IRQ_HANDLED;
 384 }
 385
 386 static irqreturn_t adc12138_eoc_handler(int irq, void *p)
 387 {
 388         struct iio_dev *indio_dev = p;
 389         struct adc12138 *adc = iio_priv(indio_dev);
 390
 391         complete(&adc->complete);
 392
 393         return IRQ_HANDLED;
 394 }
 395
 396 static int adc12138_probe(struct spi_device *spi)
 397 {
 398         struct iio_dev *indio_dev;
 399         struct adc12138 *adc;
 400         int ret;
 401
 402         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));
 403         if (!indio_dev)
 404                 return -ENOMEM;
 405
 406         adc = iio_priv(indio_dev);
 407         adc->spi = spi;
 408         adc->id = spi_get_device_id(spi)->driver_data;
 409         mutex_init(&adc->lock);
 410         init_completion(&adc->complete);
 411
 412         indio_dev->name = spi_get_device_id(spi)->name;
 413         indio_dev->dev.parent = &spi->dev;
 414         indio_dev->info = &adc12138_info;
 415         indio_dev->modes = INDIO_DIRECT_MODE;
 416
 417         switch (adc->id) {
 418         case adc12130:
 419         case adc12132:
 420                 indio_dev->channels = adc12132_channels;
 421                 indio_dev->num_channels = ARRAY_SIZE(adc12132_channels);
 422                 break;
 423         case adc12138:
 424                 indio_dev->channels = adc12138_channels;
 425                 indio_dev->num_channels = ARRAY_SIZE(adc12138_channels);
 426                 break;
 427         default:
 428                 return -EINVAL;
 429         }
 430
 431         ret = of_property_read_u32(spi->dev.of_node, "ti,acquisition-time",
 432                                    &adc->acquisition_time);
 433         if (ret)
 434                 adc->acquisition_time = 10;
 435
 436         adc->cclk = devm_clk_get(&spi->dev, NULL);
 437         if (IS_ERR(adc->cclk))
 438                 return PTR_ERR(adc->cclk);
 439
 440         adc->vref_p = devm_regulator_get(&spi->dev, "vref-p");
 441         if (IS_ERR(adc->vref_p))
 442                 return PTR_ERR(adc->vref_p);
 443
 444         adc->vref_n = devm_regulator_get_optional(&spi->dev, "vref-n");
 445         if (IS_ERR(adc->vref_n)) {
 446                 /*
 447                  * Assume vref_n is 0V if an optional regulator is not
 448                  * specified, otherwise return the error code.
 449                  */
 450                 ret = PTR_ERR(adc->vref_n);
 451                 if (ret != -ENODEV)
 452                         return ret;
 453         }
 454
 455         ret = devm_request_irq(&spi->dev, spi->irq, adc12138_eoc_handler,
 456                                IRQF_TRIGGER_RISING, indio_dev->name, indio_dev);
 457         if (ret)
 458                 return ret;
 459
 460         ret = clk_prepare_enable(adc->cclk);
 461         if (ret)
 462                 return ret;
 463
 464         ret = regulator_enable(adc->vref_p);
 465         if (ret)
 466                 goto err_clk_disable;
 467
 468         if (!IS_ERR(adc->vref_n)) {
 469                 ret = regulator_enable(adc->vref_n);
 470                 if (ret)
 471                         goto err_vref_p_disable;
 472         }
 473
 474         ret = adc12138_init(adc);
 475         if (ret)
 476                 goto err_vref_n_disable;
 477
 478         spi_set_drvdata(spi, indio_dev);
 479
 480         ret = iio_triggered_buffer_setup(indio_dev, NULL,
 481                                          adc12138_trigger_handler, NULL);
 482         if (ret)
 483                 goto err_vref_n_disable;
 484
 485         ret = iio_device_register(indio_dev);
 486         if (ret)
 487                 goto err_buffer_cleanup;
 488
 489         return 0;
 490 err_buffer_cleanup:
 491         iio_triggered_buffer_cleanup(indio_dev);
 492 err_vref_n_disable:
 493         if (!IS_ERR(adc->vref_n))
 494                 regulator_disable(adc->vref_n);
 495 err_vref_p_disable:
 496         regulator_disable(adc->vref_p);
 497 err_clk_disable:
 498         clk_disable_unprepare(adc->cclk);
 499
 500         return ret;
 501 }
 502
 503 static int adc12138_remove(struct spi_device *spi)
 504 {
 505         struct iio_dev *indio_dev = spi_get_drvdata(spi);
 506         struct adc12138 *adc = iio_priv(indio_dev);
 507
 508         iio_device_unregister(indio_dev);
 509         iio_triggered_buffer_cleanup(indio_dev);
 510         if (!IS_ERR(adc->vref_n))
 511                 regulator_disable(adc->vref_n);
 512         regulator_disable(adc->vref_p);
 513         clk_disable_unprepare(adc->cclk);
 514
 515         return 0;
 516 }
 517
 518 #ifdef CONFIG_OF
 519
 520 static const struct of_device_id adc12138_dt_ids[] = {
 521         { .compatible = "ti,adc12130", },
 522         { .compatible = "ti,adc12132", },
 523         { .compatible = "ti,adc12138", },
 524         {}
 525 };
 526 MODULE_DEVICE_TABLE(of, adc12138_dt_ids);
 527
 528 #endif
 529
 530 static const struct spi_device_id adc12138_id[] = {
 531         { "adc12130", adc12130 },
 532         { "adc12132", adc12132 },
 533         { "adc12138", adc12138 },
 534         {}
 535 };
 536 MODULE_DEVICE_TABLE(spi, adc12138_id);
 537
 538 static struct spi_driver adc12138_driver = {
 539         .driver = {
 540                 .name = "adc12138",
 541                 .of_match_table = of_match_ptr(adc12138_dt_ids),
 542         },
 543         .probe = adc12138_probe,
 544         .remove = adc12138_remove,
 545         .id_table = adc12138_id,
 546 };
 547 module_spi_driver(adc12138_driver);
 548
 549 MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>");
 550 MODULE_DESCRIPTION("ADC12130/ADC12132/ADC12138 driver");
 551 MODULE_LICENSE("GPL v2");