drivers/iio/adc/ad7266.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * AD7266/65 SPI ADC driver
   4  *
   5  * Copyright 2012 Analog Devices Inc.
   6  */
   7
   8 #include <linux/device.h>
   9 #include <linux/kernel.h>
  10 #include <linux/slab.h>
  11 #include <linux/spi/spi.h>
  12 #include <linux/regulator/consumer.h>
  13 #include <linux/err.h>
  14 #include <linux/gpio/consumer.h>
  15 #include <linux/module.h>
  16
  17 #include <linux/interrupt.h>
  18
  19 #include <linux/iio/iio.h>
  20 #include <linux/iio/buffer.h>
  21 #include <linux/iio/trigger_consumer.h>
  22 #include <linux/iio/triggered_buffer.h>
  23
  24 #include <linux/platform_data/ad7266.h>
  25
  26 struct ad7266_state {
  27         struct spi_device       *spi;
  28         struct regulator        *reg;
  29         unsigned long           vref_mv;
  30
  31         struct spi_transfer     single_xfer[3];
  32         struct spi_message      single_msg;
  33
  34         enum ad7266_range       range;
  35         enum ad7266_mode        mode;
  36         bool                    fixed_addr;
  37         struct gpio_desc        *gpios[3];
  38
  39         /*
  40          * DMA (thus cache coherency maintenance) requires the
  41          * transfer buffers to live in their own cache lines.
  42          * The buffer needs to be large enough to hold two samples (4 bytes) and
  43          * the naturally aligned timestamp (8 bytes).
  44          */
  45         struct {
  46                 __be16 sample[2];
  47                 s64 timestamp;
  48         } data ____cacheline_aligned;
  49 };
  50
  51 static int ad7266_wakeup(struct ad7266_state *st)
  52 {
  53         /* Any read with >= 2 bytes will wake the device */
  54         return spi_read(st->spi, &st->data.sample[0], 2);
  55 }
  56
  57 static int ad7266_powerdown(struct ad7266_state *st)
  58 {
  59         /* Any read with < 2 bytes will powerdown the device */
  60         return spi_read(st->spi, &st->data.sample[0], 1);
  61 }
  62
  63 static int ad7266_preenable(struct iio_dev *indio_dev)
  64 {
  65         struct ad7266_state *st = iio_priv(indio_dev);
  66         return ad7266_wakeup(st);
  67 }
  68
  69 static int ad7266_postdisable(struct iio_dev *indio_dev)
  70 {
  71         struct ad7266_state *st = iio_priv(indio_dev);
  72         return ad7266_powerdown(st);
  73 }
  74
  75 static const struct iio_buffer_setup_ops iio_triggered_buffer_setup_ops = {
  76         .preenable = &ad7266_preenable,
  77         .postdisable = &ad7266_postdisable,
  78 };
  79
  80 static irqreturn_t ad7266_trigger_handler(int irq, void *p)
  81 {
  82         struct iio_poll_func *pf = p;
  83         struct iio_dev *indio_dev = pf->indio_dev;
  84         struct ad7266_state *st = iio_priv(indio_dev);
  85         int ret;
  86
  87         ret = spi_read(st->spi, st->data.sample, 4);
  88         if (ret == 0) {
  89                 iio_push_to_buffers_with_timestamp(indio_dev, &st->data,
  90                             pf->timestamp);
  91         }
  92
  93         iio_trigger_notify_done(indio_dev->trig);
  94
  95         return IRQ_HANDLED;
  96 }
  97
  98 static void ad7266_select_input(struct ad7266_state *st, unsigned int nr)
  99 {
 100         unsigned int i;
 101
 102         if (st->fixed_addr)
 103                 return;
 104
 105         switch (st->mode) {
 106         case AD7266_MODE_SINGLE_ENDED:
 107                 nr >>= 1;
 108                 break;
 109         case AD7266_MODE_PSEUDO_DIFF:
 110                 nr |= 1;
 111                 break;
 112         case AD7266_MODE_DIFF:
 113                 nr &= ~1;
 114                 break;
 115         }
 116
 117         for (i = 0; i < 3; ++i)
 118                 gpiod_set_value(st->gpios[i], (bool)(nr & BIT(i)));
 119 }
 120
 121 static int ad7266_update_scan_mode(struct iio_dev *indio_dev,
 122         const unsigned long *scan_mask)
 123 {
 124         struct ad7266_state *st = iio_priv(indio_dev);
 125         unsigned int nr = find_first_bit(scan_mask, indio_dev->masklength);
 126
 127         ad7266_select_input(st, nr);
 128
 129         return 0;
 130 }
 131
 132 static int ad7266_read_single(struct ad7266_state *st, int *val,
 133         unsigned int address)
 134 {
 135         int ret;
 136
 137         ad7266_select_input(st, address);
 138
 139         ret = spi_sync(st->spi, &st->single_msg);
 140         *val = be16_to_cpu(st->data.sample[address % 2]);
 141
 142         return ret;
 143 }
 144
 145 static int ad7266_read_raw(struct iio_dev *indio_dev,
 146         struct iio_chan_spec const *chan, int *val, int *val2, long m)
 147 {
 148         struct ad7266_state *st = iio_priv(indio_dev);
 149         unsigned long scale_mv;
 150         int ret;
 151
 152         switch (m) {
 153         case IIO_CHAN_INFO_RAW:
 154                 ret = iio_device_claim_direct_mode(indio_dev);
 155                 if (ret)
 156                         return ret;
 157                 ret = ad7266_read_single(st, val, chan->address);
 158                 iio_device_release_direct_mode(indio_dev);
 159
 160                 *val = (*val >> 2) & 0xfff;
 161                 if (chan->scan_type.sign == 's')
 162                         *val = sign_extend32(*val, 11);
 163
 164                 return IIO_VAL_INT;
 165         case IIO_CHAN_INFO_SCALE:
 166                 scale_mv = st->vref_mv;
 167                 if (st->mode == AD7266_MODE_DIFF)
 168                         scale_mv *= 2;
 169                 if (st->range == AD7266_RANGE_2VREF)
 170                         scale_mv *= 2;
 171
 172                 *val = scale_mv;
 173                 *val2 = chan->scan_type.realbits;
 174                 return IIO_VAL_FRACTIONAL_LOG2;
 175         case IIO_CHAN_INFO_OFFSET:
 176                 if (st->range == AD7266_RANGE_2VREF &&
 177                         st->mode != AD7266_MODE_DIFF)
 178                         *val = 2048;
 179                 else
 180                         *val = 0;
 181                 return IIO_VAL_INT;
 182         }
 183         return -EINVAL;
 184 }
 185
 186 #define AD7266_CHAN(_chan, _sign) {                     \
 187         .type = IIO_VOLTAGE,                            \
 188         .indexed = 1,                                   \
 189         .channel = (_chan),                             \
 190         .address = (_chan),                             \
 191         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),   \
 192         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
 193                 | BIT(IIO_CHAN_INFO_OFFSET),                    \
 194         .scan_index = (_chan),                          \
 195         .scan_type = {                                  \
 196                 .sign = (_sign),                        \
 197                 .realbits = 12,                         \
 198                 .storagebits = 16,                      \
 199                 .shift = 2,                             \
 200                 .endianness = IIO_BE,                   \
 201         },                                              \
 202 }
 203
 204 #define AD7266_DECLARE_SINGLE_ENDED_CHANNELS(_name, _sign) \
 205 const struct iio_chan_spec ad7266_channels_##_name[] = { \
 206         AD7266_CHAN(0, (_sign)), \
 207         AD7266_CHAN(1, (_sign)), \
 208         AD7266_CHAN(2, (_sign)), \
 209         AD7266_CHAN(3, (_sign)), \
 210         AD7266_CHAN(4, (_sign)), \
 211         AD7266_CHAN(5, (_sign)), \
 212         AD7266_CHAN(6, (_sign)), \
 213         AD7266_CHAN(7, (_sign)), \
 214         AD7266_CHAN(8, (_sign)), \
 215         AD7266_CHAN(9, (_sign)), \
 216         AD7266_CHAN(10, (_sign)), \
 217         AD7266_CHAN(11, (_sign)), \
 218         IIO_CHAN_SOFT_TIMESTAMP(13), \
 219 }
 220
 221 #define AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(_name, _sign) \
 222 const struct iio_chan_spec ad7266_channels_##_name##_fixed[] = { \
 223         AD7266_CHAN(0, (_sign)), \
 224         AD7266_CHAN(1, (_sign)), \
 225         IIO_CHAN_SOFT_TIMESTAMP(2), \
 226 }
 227
 228 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS(u, 'u');
 229 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS(s, 's');
 230 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(u, 'u');
 231 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(s, 's');
 232
 233 #define AD7266_CHAN_DIFF(_chan, _sign) {                        \
 234         .type = IIO_VOLTAGE,                            \
 235         .indexed = 1,                                   \
 236         .channel = (_chan) * 2,                         \
 237         .channel2 = (_chan) * 2 + 1,                    \
 238         .address = (_chan),                             \
 239         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),   \
 240         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE)    \
 241                 | BIT(IIO_CHAN_INFO_OFFSET),                    \
 242         .scan_index = (_chan),                          \
 243         .scan_type = {                                  \
 244                 .sign = _sign,                  \
 245                 .realbits = 12,                         \
 246                 .storagebits = 16,                      \
 247                 .shift = 2,                             \
 248                 .endianness = IIO_BE,                   \
 249         },                                              \
 250         .differential = 1,                              \
 251 }
 252
 253 #define AD7266_DECLARE_DIFF_CHANNELS(_name, _sign) \
 254 const struct iio_chan_spec ad7266_channels_diff_##_name[] = { \
 255         AD7266_CHAN_DIFF(0, (_sign)), \
 256         AD7266_CHAN_DIFF(1, (_sign)), \
 257         AD7266_CHAN_DIFF(2, (_sign)), \
 258         AD7266_CHAN_DIFF(3, (_sign)), \
 259         AD7266_CHAN_DIFF(4, (_sign)), \
 260         AD7266_CHAN_DIFF(5, (_sign)), \
 261         IIO_CHAN_SOFT_TIMESTAMP(6), \
 262 }
 263
 264 static AD7266_DECLARE_DIFF_CHANNELS(s, 's');
 265 static AD7266_DECLARE_DIFF_CHANNELS(u, 'u');
 266
 267 #define AD7266_DECLARE_DIFF_CHANNELS_FIXED(_name, _sign) \
 268 const struct iio_chan_spec ad7266_channels_diff_fixed_##_name[] = { \
 269         AD7266_CHAN_DIFF(0, (_sign)), \
 270         AD7266_CHAN_DIFF(1, (_sign)), \
 271         IIO_CHAN_SOFT_TIMESTAMP(2), \
 272 }
 273
 274 static AD7266_DECLARE_DIFF_CHANNELS_FIXED(s, 's');
 275 static AD7266_DECLARE_DIFF_CHANNELS_FIXED(u, 'u');
 276
 277 static const struct iio_info ad7266_info = {
 278         .read_raw = &ad7266_read_raw,
 279         .update_scan_mode = &ad7266_update_scan_mode,
 280 };
 281
 282 static const unsigned long ad7266_available_scan_masks[] = {
 283         0x003,
 284         0x00c,
 285         0x030,
 286         0x0c0,
 287         0x300,
 288         0xc00,
 289         0x000,
 290 };
 291
 292 static const unsigned long ad7266_available_scan_masks_diff[] = {
 293         0x003,
 294         0x00c,
 295         0x030,
 296         0x000,
 297 };
 298
 299 static const unsigned long ad7266_available_scan_masks_fixed[] = {
 300         0x003,
 301         0x000,
 302 };
 303
 304 struct ad7266_chan_info {
 305         const struct iio_chan_spec *channels;
 306         unsigned int num_channels;
 307         const unsigned long *scan_masks;
 308 };
 309
 310 #define AD7266_CHAN_INFO_INDEX(_differential, _signed, _fixed) \
 311         (((_differential) << 2) | ((_signed) << 1) | ((_fixed) << 0))
 312
 313 static const struct ad7266_chan_info ad7266_chan_infos[] = {
 314         [AD7266_CHAN_INFO_INDEX(0, 0, 0)] = {
 315                 .channels = ad7266_channels_u,
 316                 .num_channels = ARRAY_SIZE(ad7266_channels_u),
 317                 .scan_masks = ad7266_available_scan_masks,
 318         },
 319         [AD7266_CHAN_INFO_INDEX(0, 0, 1)] = {
 320                 .channels = ad7266_channels_u_fixed,
 321                 .num_channels = ARRAY_SIZE(ad7266_channels_u_fixed),
 322                 .scan_masks = ad7266_available_scan_masks_fixed,
 323         },
 324         [AD7266_CHAN_INFO_INDEX(0, 1, 0)] = {
 325                 .channels = ad7266_channels_s,
 326                 .num_channels = ARRAY_SIZE(ad7266_channels_s),
 327                 .scan_masks = ad7266_available_scan_masks,
 328         },
 329         [AD7266_CHAN_INFO_INDEX(0, 1, 1)] = {
 330                 .channels = ad7266_channels_s_fixed,
 331                 .num_channels = ARRAY_SIZE(ad7266_channels_s_fixed),
 332                 .scan_masks = ad7266_available_scan_masks_fixed,
 333         },
 334         [AD7266_CHAN_INFO_INDEX(1, 0, 0)] = {
 335                 .channels = ad7266_channels_diff_u,
 336                 .num_channels = ARRAY_SIZE(ad7266_channels_diff_u),
 337                 .scan_masks = ad7266_available_scan_masks_diff,
 338         },
 339         [AD7266_CHAN_INFO_INDEX(1, 0, 1)] = {
 340                 .channels = ad7266_channels_diff_fixed_u,
 341                 .num_channels = ARRAY_SIZE(ad7266_channels_diff_fixed_u),
 342                 .scan_masks = ad7266_available_scan_masks_fixed,
 343         },
 344         [AD7266_CHAN_INFO_INDEX(1, 1, 0)] = {
 345                 .channels = ad7266_channels_diff_s,
 346                 .num_channels = ARRAY_SIZE(ad7266_channels_diff_s),
 347                 .scan_masks = ad7266_available_scan_masks_diff,
 348         },
 349         [AD7266_CHAN_INFO_INDEX(1, 1, 1)] = {
 350                 .channels = ad7266_channels_diff_fixed_s,
 351                 .num_channels = ARRAY_SIZE(ad7266_channels_diff_fixed_s),
 352                 .scan_masks = ad7266_available_scan_masks_fixed,
 353         },
 354 };
 355
 356 static void ad7266_init_channels(struct iio_dev *indio_dev)
 357 {
 358         struct ad7266_state *st = iio_priv(indio_dev);
 359         bool is_differential, is_signed;
 360         const struct ad7266_chan_info *chan_info;
 361         int i;
 362
 363         is_differential = st->mode != AD7266_MODE_SINGLE_ENDED;
 364         is_signed = (st->range == AD7266_RANGE_2VREF) |
 365                     (st->mode == AD7266_MODE_DIFF);
 366
 367         i = AD7266_CHAN_INFO_INDEX(is_differential, is_signed, st->fixed_addr);
 368         chan_info = &ad7266_chan_infos[i];
 369
 370         indio_dev->channels = chan_info->channels;
 371         indio_dev->num_channels = chan_info->num_channels;
 372         indio_dev->available_scan_masks = chan_info->scan_masks;
 373         indio_dev->masklength = chan_info->num_channels - 1;
 374 }
 375
 376 static const char * const ad7266_gpio_labels[] = {
 377         "ad0", "ad1", "ad2",
 378 };
 379
 380 static int ad7266_probe(struct spi_device *spi)
 381 {
 382         struct ad7266_platform_data *pdata = spi->dev.platform_data;
 383         struct iio_dev *indio_dev;
 384         struct ad7266_state *st;
 385         unsigned int i;
 386         int ret;
 387
 388         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
 389         if (indio_dev == NULL)
 390                 return -ENOMEM;
 391
 392         st = iio_priv(indio_dev);
 393
 394         st->reg = devm_regulator_get_optional(&spi->dev, "vref");
 395         if (!IS_ERR(st->reg)) {
 396                 ret = regulator_enable(st->reg);
 397                 if (ret)
 398                         return ret;
 399
 400                 ret = regulator_get_voltage(st->reg);
 401                 if (ret < 0)
 402                         goto error_disable_reg;
 403
 404                 st->vref_mv = ret / 1000;
 405         } else {
 406                 /* Any other error indicates that the regulator does exist */
 407                 if (PTR_ERR(st->reg) != -ENODEV)
 408                         return PTR_ERR(st->reg);
 409                 /* Use internal reference */
 410                 st->vref_mv = 2500;
 411         }
 412
 413         if (pdata) {
 414                 st->fixed_addr = pdata->fixed_addr;
 415                 st->mode = pdata->mode;
 416                 st->range = pdata->range;
 417
 418                 if (!st->fixed_addr) {
 419                         for (i = 0; i < ARRAY_SIZE(st->gpios); ++i) {
 420                                 st->gpios[i] = devm_gpiod_get(&spi->dev,
 421                                                       ad7266_gpio_labels[i],
 422                                                       GPIOD_OUT_LOW);
 423                                 if (IS_ERR(st->gpios[i])) {
 424                                         ret = PTR_ERR(st->gpios[i]);
 425                                         goto error_disable_reg;
 426                                 }
 427                         }
 428                 }
 429         } else {
 430                 st->fixed_addr = true;
 431                 st->range = AD7266_RANGE_VREF;
 432                 st->mode = AD7266_MODE_DIFF;
 433         }
 434
 435         spi_set_drvdata(spi, indio_dev);
 436         st->spi = spi;
 437
 438         indio_dev->name = spi_get_device_id(spi)->name;
 439         indio_dev->modes = INDIO_DIRECT_MODE;
 440         indio_dev->info = &ad7266_info;
 441
 442         ad7266_init_channels(indio_dev);
 443
 444         /* wakeup */
 445         st->single_xfer[0].rx_buf = &st->data.sample[0];
 446         st->single_xfer[0].len = 2;
 447         st->single_xfer[0].cs_change = 1;
 448         /* conversion */
 449         st->single_xfer[1].rx_buf = st->data.sample;
 450         st->single_xfer[1].len = 4;
 451         st->single_xfer[1].cs_change = 1;
 452         /* powerdown */
 453         st->single_xfer[2].tx_buf = &st->data.sample[0];
 454         st->single_xfer[2].len = 1;
 455
 456         spi_message_init(&st->single_msg);
 457         spi_message_add_tail(&st->single_xfer[0], &st->single_msg);
 458         spi_message_add_tail(&st->single_xfer[1], &st->single_msg);
 459         spi_message_add_tail(&st->single_xfer[2], &st->single_msg);
 460
 461         ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
 462                 &ad7266_trigger_handler, &iio_triggered_buffer_setup_ops);
 463         if (ret)
 464                 goto error_disable_reg;
 465
 466         ret = iio_device_register(indio_dev);
 467         if (ret)
 468                 goto error_buffer_cleanup;
 469
 470         return 0;
 471
 472 error_buffer_cleanup:
 473         iio_triggered_buffer_cleanup(indio_dev);
 474 error_disable_reg:
 475         if (!IS_ERR(st->reg))
 476                 regulator_disable(st->reg);
 477
 478         return ret;
 479 }
 480
 481 static int ad7266_remove(struct spi_device *spi)
 482 {
 483         struct iio_dev *indio_dev = spi_get_drvdata(spi);
 484         struct ad7266_state *st = iio_priv(indio_dev);
 485
 486         iio_device_unregister(indio_dev);
 487         iio_triggered_buffer_cleanup(indio_dev);
 488         if (!IS_ERR(st->reg))
 489                 regulator_disable(st->reg);
 490
 491         return 0;
 492 }
 493
 494 static const struct spi_device_id ad7266_id[] = {
 495         {"ad7265", 0},
 496         {"ad7266", 0},
 497         { }
 498 };
 499 MODULE_DEVICE_TABLE(spi, ad7266_id);
 500
 501 static struct spi_driver ad7266_driver = {
 502         .driver = {
 503                 .name   = "ad7266",
 504         },
 505         .probe          = ad7266_probe,
 506         .remove         = ad7266_remove,
 507         .id_table       = ad7266_id,
 508 };
 509 module_spi_driver(ad7266_driver);
 510
 511 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
 512 MODULE_DESCRIPTION("Analog Devices AD7266/65 ADC");
 513 MODULE_LICENSE("GPL v2");