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) may require 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 __aligned(IIO_DMA_MINALIGN);
  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,
 163                                              chan->scan_type.realbits - 1);
 164
 165                 return IIO_VAL_INT;
 166         case IIO_CHAN_INFO_SCALE:
 167                 scale_mv = st->vref_mv;
 168                 if (st->mode == AD7266_MODE_DIFF)
 169                         scale_mv *= 2;
 170                 if (st->range == AD7266_RANGE_2VREF)
 171                         scale_mv *= 2;
 172
 173                 *val = scale_mv;
 174                 *val2 = chan->scan_type.realbits;
 175                 return IIO_VAL_FRACTIONAL_LOG2;
 176         case IIO_CHAN_INFO_OFFSET:
 177                 if (st->range == AD7266_RANGE_2VREF &&
 178                         st->mode != AD7266_MODE_DIFF)
 179                         *val = 2048;
 180                 else
 181                         *val = 0;
 182                 return IIO_VAL_INT;
 183         }
 184         return -EINVAL;
 185 }
 186
 187 #define AD7266_CHAN(_chan, _sign) {                     \
 188         .type = IIO_VOLTAGE,                            \
 189         .indexed = 1,                                   \
 190         .channel = (_chan),                             \
 191         .address = (_chan),                             \
 192         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),   \
 193         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
 194                 | BIT(IIO_CHAN_INFO_OFFSET),                    \
 195         .scan_index = (_chan),                          \
 196         .scan_type = {                                  \
 197                 .sign = (_sign),                        \
 198                 .realbits = 12,                         \
 199                 .storagebits = 16,                      \
 200                 .shift = 2,                             \
 201                 .endianness = IIO_BE,                   \
 202         },                                              \
 203 }
 204
 205 #define AD7266_DECLARE_SINGLE_ENDED_CHANNELS(_name, _sign) \
 206 const struct iio_chan_spec ad7266_channels_##_name[] = { \
 207         AD7266_CHAN(0, (_sign)), \
 208         AD7266_CHAN(1, (_sign)), \
 209         AD7266_CHAN(2, (_sign)), \
 210         AD7266_CHAN(3, (_sign)), \
 211         AD7266_CHAN(4, (_sign)), \
 212         AD7266_CHAN(5, (_sign)), \
 213         AD7266_CHAN(6, (_sign)), \
 214         AD7266_CHAN(7, (_sign)), \
 215         AD7266_CHAN(8, (_sign)), \
 216         AD7266_CHAN(9, (_sign)), \
 217         AD7266_CHAN(10, (_sign)), \
 218         AD7266_CHAN(11, (_sign)), \
 219         IIO_CHAN_SOFT_TIMESTAMP(13), \
 220 }
 221
 222 #define AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(_name, _sign) \
 223 const struct iio_chan_spec ad7266_channels_##_name##_fixed[] = { \
 224         AD7266_CHAN(0, (_sign)), \
 225         AD7266_CHAN(1, (_sign)), \
 226         IIO_CHAN_SOFT_TIMESTAMP(2), \
 227 }
 228
 229 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS(u, 'u');
 230 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS(s, 's');
 231 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(u, 'u');
 232 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(s, 's');
 233
 234 #define AD7266_CHAN_DIFF(_chan, _sign) {                        \
 235         .type = IIO_VOLTAGE,                            \
 236         .indexed = 1,                                   \
 237         .channel = (_chan) * 2,                         \
 238         .channel2 = (_chan) * 2 + 1,                    \
 239         .address = (_chan),                             \
 240         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),   \
 241         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE)    \
 242                 | BIT(IIO_CHAN_INFO_OFFSET),                    \
 243         .scan_index = (_chan),                          \
 244         .scan_type = {                                  \
 245                 .sign = _sign,                  \
 246                 .realbits = 12,                         \
 247                 .storagebits = 16,                      \
 248                 .shift = 2,                             \
 249                 .endianness = IIO_BE,                   \
 250         },                                              \
 251         .differential = 1,                              \
 252 }
 253
 254 #define AD7266_DECLARE_DIFF_CHANNELS(_name, _sign) \
 255 const struct iio_chan_spec ad7266_channels_diff_##_name[] = { \
 256         AD7266_CHAN_DIFF(0, (_sign)), \
 257         AD7266_CHAN_DIFF(1, (_sign)), \
 258         AD7266_CHAN_DIFF(2, (_sign)), \
 259         AD7266_CHAN_DIFF(3, (_sign)), \
 260         AD7266_CHAN_DIFF(4, (_sign)), \
 261         AD7266_CHAN_DIFF(5, (_sign)), \
 262         IIO_CHAN_SOFT_TIMESTAMP(6), \
 263 }
 264
 265 static AD7266_DECLARE_DIFF_CHANNELS(s, 's');
 266 static AD7266_DECLARE_DIFF_CHANNELS(u, 'u');
 267
 268 #define AD7266_DECLARE_DIFF_CHANNELS_FIXED(_name, _sign) \
 269 const struct iio_chan_spec ad7266_channels_diff_fixed_##_name[] = { \
 270         AD7266_CHAN_DIFF(0, (_sign)), \
 271         AD7266_CHAN_DIFF(1, (_sign)), \
 272         IIO_CHAN_SOFT_TIMESTAMP(2), \
 273 }
 274
 275 static AD7266_DECLARE_DIFF_CHANNELS_FIXED(s, 's');
 276 static AD7266_DECLARE_DIFF_CHANNELS_FIXED(u, 'u');
 277
 278 static const struct iio_info ad7266_info = {
 279         .read_raw = &ad7266_read_raw,
 280         .update_scan_mode = &ad7266_update_scan_mode,
 281 };
 282
 283 static const unsigned long ad7266_available_scan_masks[] = {
 284         0x003,
 285         0x00c,
 286         0x030,
 287         0x0c0,
 288         0x300,
 289         0xc00,
 290         0x000,
 291 };
 292
 293 static const unsigned long ad7266_available_scan_masks_diff[] = {
 294         0x003,
 295         0x00c,
 296         0x030,
 297         0x000,
 298 };
 299
 300 static const unsigned long ad7266_available_scan_masks_fixed[] = {
 301         0x003,
 302         0x000,
 303 };
 304
 305 struct ad7266_chan_info {
 306         const struct iio_chan_spec *channels;
 307         unsigned int num_channels;
 308         const unsigned long *scan_masks;
 309 };
 310
 311 #define AD7266_CHAN_INFO_INDEX(_differential, _signed, _fixed) \
 312         (((_differential) << 2) | ((_signed) << 1) | ((_fixed) << 0))
 313
 314 static const struct ad7266_chan_info ad7266_chan_infos[] = {
 315         [AD7266_CHAN_INFO_INDEX(0, 0, 0)] = {
 316                 .channels = ad7266_channels_u,
 317                 .num_channels = ARRAY_SIZE(ad7266_channels_u),
 318                 .scan_masks = ad7266_available_scan_masks,
 319         },
 320         [AD7266_CHAN_INFO_INDEX(0, 0, 1)] = {
 321                 .channels = ad7266_channels_u_fixed,
 322                 .num_channels = ARRAY_SIZE(ad7266_channels_u_fixed),
 323                 .scan_masks = ad7266_available_scan_masks_fixed,
 324         },
 325         [AD7266_CHAN_INFO_INDEX(0, 1, 0)] = {
 326                 .channels = ad7266_channels_s,
 327                 .num_channels = ARRAY_SIZE(ad7266_channels_s),
 328                 .scan_masks = ad7266_available_scan_masks,
 329         },
 330         [AD7266_CHAN_INFO_INDEX(0, 1, 1)] = {
 331                 .channels = ad7266_channels_s_fixed,
 332                 .num_channels = ARRAY_SIZE(ad7266_channels_s_fixed),
 333                 .scan_masks = ad7266_available_scan_masks_fixed,
 334         },
 335         [AD7266_CHAN_INFO_INDEX(1, 0, 0)] = {
 336                 .channels = ad7266_channels_diff_u,
 337                 .num_channels = ARRAY_SIZE(ad7266_channels_diff_u),
 338                 .scan_masks = ad7266_available_scan_masks_diff,
 339         },
 340         [AD7266_CHAN_INFO_INDEX(1, 0, 1)] = {
 341                 .channels = ad7266_channels_diff_fixed_u,
 342                 .num_channels = ARRAY_SIZE(ad7266_channels_diff_fixed_u),
 343                 .scan_masks = ad7266_available_scan_masks_fixed,
 344         },
 345         [AD7266_CHAN_INFO_INDEX(1, 1, 0)] = {
 346                 .channels = ad7266_channels_diff_s,
 347                 .num_channels = ARRAY_SIZE(ad7266_channels_diff_s),
 348                 .scan_masks = ad7266_available_scan_masks_diff,
 349         },
 350         [AD7266_CHAN_INFO_INDEX(1, 1, 1)] = {
 351                 .channels = ad7266_channels_diff_fixed_s,
 352                 .num_channels = ARRAY_SIZE(ad7266_channels_diff_fixed_s),
 353                 .scan_masks = ad7266_available_scan_masks_fixed,
 354         },
 355 };
 356
 357 static void ad7266_init_channels(struct iio_dev *indio_dev)
 358 {
 359         struct ad7266_state *st = iio_priv(indio_dev);
 360         bool is_differential, is_signed;
 361         const struct ad7266_chan_info *chan_info;
 362         int i;
 363
 364         is_differential = st->mode != AD7266_MODE_SINGLE_ENDED;
 365         is_signed = (st->range == AD7266_RANGE_2VREF) |
 366                     (st->mode == AD7266_MODE_DIFF);
 367
 368         i = AD7266_CHAN_INFO_INDEX(is_differential, is_signed, st->fixed_addr);
 369         chan_info = &ad7266_chan_infos[i];
 370
 371         indio_dev->channels = chan_info->channels;
 372         indio_dev->num_channels = chan_info->num_channels;
 373         indio_dev->available_scan_masks = chan_info->scan_masks;
 374         indio_dev->masklength = chan_info->num_channels - 1;
 375 }
 376
 377 static const char * const ad7266_gpio_labels[] = {
 378         "ad0", "ad1", "ad2",
 379 };
 380
 381 static void ad7266_reg_disable(void *reg)
 382 {
 383         regulator_disable(reg);
 384 }
 385
 386 static int ad7266_probe(struct spi_device *spi)
 387 {
 388         struct ad7266_platform_data *pdata = spi->dev.platform_data;
 389         struct iio_dev *indio_dev;
 390         struct ad7266_state *st;
 391         unsigned int i;
 392         int ret;
 393
 394         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
 395         if (indio_dev == NULL)
 396                 return -ENOMEM;
 397
 398         st = iio_priv(indio_dev);
 399
 400         st->reg = devm_regulator_get_optional(&spi->dev, "vref");
 401         if (!IS_ERR(st->reg)) {
 402                 ret = regulator_enable(st->reg);
 403                 if (ret)
 404                         return ret;
 405
 406                 ret = devm_add_action_or_reset(&spi->dev, ad7266_reg_disable, st->reg);
 407                 if (ret)
 408                         return ret;
 409
 410                 ret = regulator_get_voltage(st->reg);
 411                 if (ret < 0)
 412                         return ret;
 413
 414                 st->vref_mv = ret / 1000;
 415         } else {
 416                 /* Any other error indicates that the regulator does exist */
 417                 if (PTR_ERR(st->reg) != -ENODEV)
 418                         return PTR_ERR(st->reg);
 419                 /* Use internal reference */
 420                 st->vref_mv = 2500;
 421         }
 422
 423         if (pdata) {
 424                 st->fixed_addr = pdata->fixed_addr;
 425                 st->mode = pdata->mode;
 426                 st->range = pdata->range;
 427
 428                 if (!st->fixed_addr) {
 429                         for (i = 0; i < ARRAY_SIZE(st->gpios); ++i) {
 430                                 st->gpios[i] = devm_gpiod_get(&spi->dev,
 431                                                       ad7266_gpio_labels[i],
 432                                                       GPIOD_OUT_LOW);
 433                                 if (IS_ERR(st->gpios[i])) {
 434                                         ret = PTR_ERR(st->gpios[i]);
 435                                         return ret;
 436                                 }
 437                         }
 438                 }
 439         } else {
 440                 st->fixed_addr = true;
 441                 st->range = AD7266_RANGE_VREF;
 442                 st->mode = AD7266_MODE_DIFF;
 443         }
 444
 445         st->spi = spi;
 446
 447         indio_dev->name = spi_get_device_id(spi)->name;
 448         indio_dev->modes = INDIO_DIRECT_MODE;
 449         indio_dev->info = &ad7266_info;
 450
 451         ad7266_init_channels(indio_dev);
 452
 453         /* wakeup */
 454         st->single_xfer[0].rx_buf = &st->data.sample[0];
 455         st->single_xfer[0].len = 2;
 456         st->single_xfer[0].cs_change = 1;
 457         /* conversion */
 458         st->single_xfer[1].rx_buf = st->data.sample;
 459         st->single_xfer[1].len = 4;
 460         st->single_xfer[1].cs_change = 1;
 461         /* powerdown */
 462         st->single_xfer[2].tx_buf = &st->data.sample[0];
 463         st->single_xfer[2].len = 1;
 464
 465         spi_message_init(&st->single_msg);
 466         spi_message_add_tail(&st->single_xfer[0], &st->single_msg);
 467         spi_message_add_tail(&st->single_xfer[1], &st->single_msg);
 468         spi_message_add_tail(&st->single_xfer[2], &st->single_msg);
 469
 470         ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev, &iio_pollfunc_store_time,
 471                 &ad7266_trigger_handler, &iio_triggered_buffer_setup_ops);
 472         if (ret)
 473                 return ret;
 474
 475         return devm_iio_device_register(&spi->dev, indio_dev);
 476 }
 477
 478 static const struct spi_device_id ad7266_id[] = {
 479         {"ad7265", 0},
 480         {"ad7266", 0},
 481         { }
 482 };
 483 MODULE_DEVICE_TABLE(spi, ad7266_id);
 484
 485 static struct spi_driver ad7266_driver = {
 486         .driver = {
 487                 .name   = "ad7266",
 488         },
 489         .probe          = ad7266_probe,
 490         .id_table       = ad7266_id,
 491 };
 492 module_spi_driver(ad7266_driver);
 493
 494 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
 495 MODULE_DESCRIPTION("Analog Devices AD7266/65 ADC");
 496 MODULE_LICENSE("GPL v2");