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         .postenable = &iio_triggered_buffer_postenable,
  78         .predisable = &iio_triggered_buffer_predisable,
  79         .postdisable = &ad7266_postdisable,
  80 };
  81
  82 static irqreturn_t ad7266_trigger_handler(int irq, void *p)
  83 {
  84         struct iio_poll_func *pf = p;
  85         struct iio_dev *indio_dev = pf->indio_dev;
  86         struct ad7266_state *st = iio_priv(indio_dev);
  87         int ret;
  88
  89         ret = spi_read(st->spi, st->data.sample, 4);
  90         if (ret == 0) {
  91                 iio_push_to_buffers_with_timestamp(indio_dev, &st->data,
  92                             pf->timestamp);
  93         }
  94
  95         iio_trigger_notify_done(indio_dev->trig);
  96
  97         return IRQ_HANDLED;
  98 }
  99
 100 static void ad7266_select_input(struct ad7266_state *st, unsigned int nr)
 101 {
 102         unsigned int i;
 103
 104         if (st->fixed_addr)
 105                 return;
 106
 107         switch (st->mode) {
 108         case AD7266_MODE_SINGLE_ENDED:
 109                 nr >>= 1;
 110                 break;
 111         case AD7266_MODE_PSEUDO_DIFF:
 112                 nr |= 1;
 113                 break;
 114         case AD7266_MODE_DIFF:
 115                 nr &= ~1;
 116                 break;
 117         }
 118
 119         for (i = 0; i < 3; ++i)
 120                 gpiod_set_value(st->gpios[i], (bool)(nr & BIT(i)));
 121 }
 122
 123 static int ad7266_update_scan_mode(struct iio_dev *indio_dev,
 124         const unsigned long *scan_mask)
 125 {
 126         struct ad7266_state *st = iio_priv(indio_dev);
 127         unsigned int nr = find_first_bit(scan_mask, indio_dev->masklength);
 128
 129         ad7266_select_input(st, nr);
 130
 131         return 0;
 132 }
 133
 134 static int ad7266_read_single(struct ad7266_state *st, int *val,
 135         unsigned int address)
 136 {
 137         int ret;
 138
 139         ad7266_select_input(st, address);
 140
 141         ret = spi_sync(st->spi, &st->single_msg);
 142         *val = be16_to_cpu(st->data.sample[address % 2]);
 143
 144         return ret;
 145 }
 146
 147 static int ad7266_read_raw(struct iio_dev *indio_dev,
 148         struct iio_chan_spec const *chan, int *val, int *val2, long m)
 149 {
 150         struct ad7266_state *st = iio_priv(indio_dev);
 151         unsigned long scale_mv;
 152         int ret;
 153
 154         switch (m) {
 155         case IIO_CHAN_INFO_RAW:
 156                 ret = iio_device_claim_direct_mode(indio_dev);
 157                 if (ret)
 158                         return ret;
 159                 ret = ad7266_read_single(st, val, chan->address);
 160                 iio_device_release_direct_mode(indio_dev);
 161
 162                 *val = (*val >> 2) & 0xfff;
 163                 if (chan->scan_type.sign == 's')
 164                         *val = sign_extend32(*val, 11);
 165
 166                 return IIO_VAL_INT;
 167         case IIO_CHAN_INFO_SCALE:
 168                 scale_mv = st->vref_mv;
 169                 if (st->mode == AD7266_MODE_DIFF)
 170                         scale_mv *= 2;
 171                 if (st->range == AD7266_RANGE_2VREF)
 172                         scale_mv *= 2;
 173
 174                 *val = scale_mv;
 175                 *val2 = chan->scan_type.realbits;
 176                 return IIO_VAL_FRACTIONAL_LOG2;
 177         case IIO_CHAN_INFO_OFFSET:
 178                 if (st->range == AD7266_RANGE_2VREF &&
 179                         st->mode != AD7266_MODE_DIFF)
 180                         *val = 2048;
 181                 else
 182                         *val = 0;
 183                 return IIO_VAL_INT;
 184         }
 185         return -EINVAL;
 186 }
 187
 188 #define AD7266_CHAN(_chan, _sign) {                     \
 189         .type = IIO_VOLTAGE,                            \
 190         .indexed = 1,                                   \
 191         .channel = (_chan),                             \
 192         .address = (_chan),                             \
 193         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),   \
 194         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
 195                 | BIT(IIO_CHAN_INFO_OFFSET),                    \
 196         .scan_index = (_chan),                          \
 197         .scan_type = {                                  \
 198                 .sign = (_sign),                        \
 199                 .realbits = 12,                         \
 200                 .storagebits = 16,                      \
 201                 .shift = 2,                             \
 202                 .endianness = IIO_BE,                   \
 203         },                                              \
 204 }
 205
 206 #define AD7266_DECLARE_SINGLE_ENDED_CHANNELS(_name, _sign) \
 207 const struct iio_chan_spec ad7266_channels_##_name[] = { \
 208         AD7266_CHAN(0, (_sign)), \
 209         AD7266_CHAN(1, (_sign)), \
 210         AD7266_CHAN(2, (_sign)), \
 211         AD7266_CHAN(3, (_sign)), \
 212         AD7266_CHAN(4, (_sign)), \
 213         AD7266_CHAN(5, (_sign)), \
 214         AD7266_CHAN(6, (_sign)), \
 215         AD7266_CHAN(7, (_sign)), \
 216         AD7266_CHAN(8, (_sign)), \
 217         AD7266_CHAN(9, (_sign)), \
 218         AD7266_CHAN(10, (_sign)), \
 219         AD7266_CHAN(11, (_sign)), \
 220         IIO_CHAN_SOFT_TIMESTAMP(13), \
 221 }
 222
 223 #define AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(_name, _sign) \
 224 const struct iio_chan_spec ad7266_channels_##_name##_fixed[] = { \
 225         AD7266_CHAN(0, (_sign)), \
 226         AD7266_CHAN(1, (_sign)), \
 227         IIO_CHAN_SOFT_TIMESTAMP(2), \
 228 }
 229
 230 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS(u, 'u');
 231 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS(s, 's');
 232 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(u, 'u');
 233 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(s, 's');
 234
 235 #define AD7266_CHAN_DIFF(_chan, _sign) {                        \
 236         .type = IIO_VOLTAGE,                            \
 237         .indexed = 1,                                   \
 238         .channel = (_chan) * 2,                         \
 239         .channel2 = (_chan) * 2 + 1,                    \
 240         .address = (_chan),                             \
 241         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),   \
 242         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE)    \
 243                 | BIT(IIO_CHAN_INFO_OFFSET),                    \
 244         .scan_index = (_chan),                          \
 245         .scan_type = {                                  \
 246                 .sign = _sign,                  \
 247                 .realbits = 12,                         \
 248                 .storagebits = 16,                      \
 249                 .shift = 2,                             \
 250                 .endianness = IIO_BE,                   \
 251         },                                              \
 252         .differential = 1,                              \
 253 }
 254
 255 #define AD7266_DECLARE_DIFF_CHANNELS(_name, _sign) \
 256 const struct iio_chan_spec ad7266_channels_diff_##_name[] = { \
 257         AD7266_CHAN_DIFF(0, (_sign)), \
 258         AD7266_CHAN_DIFF(1, (_sign)), \
 259         AD7266_CHAN_DIFF(2, (_sign)), \
 260         AD7266_CHAN_DIFF(3, (_sign)), \
 261         AD7266_CHAN_DIFF(4, (_sign)), \
 262         AD7266_CHAN_DIFF(5, (_sign)), \
 263         IIO_CHAN_SOFT_TIMESTAMP(6), \
 264 }
 265
 266 static AD7266_DECLARE_DIFF_CHANNELS(s, 's');
 267 static AD7266_DECLARE_DIFF_CHANNELS(u, 'u');
 268
 269 #define AD7266_DECLARE_DIFF_CHANNELS_FIXED(_name, _sign) \
 270 const struct iio_chan_spec ad7266_channels_diff_fixed_##_name[] = { \
 271         AD7266_CHAN_DIFF(0, (_sign)), \
 272         AD7266_CHAN_DIFF(1, (_sign)), \
 273         IIO_CHAN_SOFT_TIMESTAMP(2), \
 274 }
 275
 276 static AD7266_DECLARE_DIFF_CHANNELS_FIXED(s, 's');
 277 static AD7266_DECLARE_DIFF_CHANNELS_FIXED(u, 'u');
 278
 279 static const struct iio_info ad7266_info = {
 280         .read_raw = &ad7266_read_raw,
 281         .update_scan_mode = &ad7266_update_scan_mode,
 282 };
 283
 284 static const unsigned long ad7266_available_scan_masks[] = {
 285         0x003,
 286         0x00c,
 287         0x030,
 288         0x0c0,
 289         0x300,
 290         0xc00,
 291         0x000,
 292 };
 293
 294 static const unsigned long ad7266_available_scan_masks_diff[] = {
 295         0x003,
 296         0x00c,
 297         0x030,
 298         0x000,
 299 };
 300
 301 static const unsigned long ad7266_available_scan_masks_fixed[] = {
 302         0x003,
 303         0x000,
 304 };
 305
 306 struct ad7266_chan_info {
 307         const struct iio_chan_spec *channels;
 308         unsigned int num_channels;
 309         const unsigned long *scan_masks;
 310 };
 311
 312 #define AD7266_CHAN_INFO_INDEX(_differential, _signed, _fixed) \
 313         (((_differential) << 2) | ((_signed) << 1) | ((_fixed) << 0))
 314
 315 static const struct ad7266_chan_info ad7266_chan_infos[] = {
 316         [AD7266_CHAN_INFO_INDEX(0, 0, 0)] = {
 317                 .channels = ad7266_channels_u,
 318                 .num_channels = ARRAY_SIZE(ad7266_channels_u),
 319                 .scan_masks = ad7266_available_scan_masks,
 320         },
 321         [AD7266_CHAN_INFO_INDEX(0, 0, 1)] = {
 322                 .channels = ad7266_channels_u_fixed,
 323                 .num_channels = ARRAY_SIZE(ad7266_channels_u_fixed),
 324                 .scan_masks = ad7266_available_scan_masks_fixed,
 325         },
 326         [AD7266_CHAN_INFO_INDEX(0, 1, 0)] = {
 327                 .channels = ad7266_channels_s,
 328                 .num_channels = ARRAY_SIZE(ad7266_channels_s),
 329                 .scan_masks = ad7266_available_scan_masks,
 330         },
 331         [AD7266_CHAN_INFO_INDEX(0, 1, 1)] = {
 332                 .channels = ad7266_channels_s_fixed,
 333                 .num_channels = ARRAY_SIZE(ad7266_channels_s_fixed),
 334                 .scan_masks = ad7266_available_scan_masks_fixed,
 335         },
 336         [AD7266_CHAN_INFO_INDEX(1, 0, 0)] = {
 337                 .channels = ad7266_channels_diff_u,
 338                 .num_channels = ARRAY_SIZE(ad7266_channels_diff_u),
 339                 .scan_masks = ad7266_available_scan_masks_diff,
 340         },
 341         [AD7266_CHAN_INFO_INDEX(1, 0, 1)] = {
 342                 .channels = ad7266_channels_diff_fixed_u,
 343                 .num_channels = ARRAY_SIZE(ad7266_channels_diff_fixed_u),
 344                 .scan_masks = ad7266_available_scan_masks_fixed,
 345         },
 346         [AD7266_CHAN_INFO_INDEX(1, 1, 0)] = {
 347                 .channels = ad7266_channels_diff_s,
 348                 .num_channels = ARRAY_SIZE(ad7266_channels_diff_s),
 349                 .scan_masks = ad7266_available_scan_masks_diff,
 350         },
 351         [AD7266_CHAN_INFO_INDEX(1, 1, 1)] = {
 352                 .channels = ad7266_channels_diff_fixed_s,
 353                 .num_channels = ARRAY_SIZE(ad7266_channels_diff_fixed_s),
 354                 .scan_masks = ad7266_available_scan_masks_fixed,
 355         },
 356 };
 357
 358 static void ad7266_init_channels(struct iio_dev *indio_dev)
 359 {
 360         struct ad7266_state *st = iio_priv(indio_dev);
 361         bool is_differential, is_signed;
 362         const struct ad7266_chan_info *chan_info;
 363         int i;
 364
 365         is_differential = st->mode != AD7266_MODE_SINGLE_ENDED;
 366         is_signed = (st->range == AD7266_RANGE_2VREF) |
 367                     (st->mode == AD7266_MODE_DIFF);
 368
 369         i = AD7266_CHAN_INFO_INDEX(is_differential, is_signed, st->fixed_addr);
 370         chan_info = &ad7266_chan_infos[i];
 371
 372         indio_dev->channels = chan_info->channels;
 373         indio_dev->num_channels = chan_info->num_channels;
 374         indio_dev->available_scan_masks = chan_info->scan_masks;
 375         indio_dev->masklength = chan_info->num_channels - 1;
 376 }
 377
 378 static const char * const ad7266_gpio_labels[] = {
 379         "ad0", "ad1", "ad2",
 380 };
 381
 382 static int ad7266_probe(struct spi_device *spi)
 383 {
 384         struct ad7266_platform_data *pdata = spi->dev.platform_data;
 385         struct iio_dev *indio_dev;
 386         struct ad7266_state *st;
 387         unsigned int i;
 388         int ret;
 389
 390         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
 391         if (indio_dev == NULL)
 392                 return -ENOMEM;
 393
 394         st = iio_priv(indio_dev);
 395
 396         st->reg = devm_regulator_get_optional(&spi->dev, "vref");
 397         if (!IS_ERR(st->reg)) {
 398                 ret = regulator_enable(st->reg);
 399                 if (ret)
 400                         return ret;
 401
 402                 ret = regulator_get_voltage(st->reg);
 403                 if (ret < 0)
 404                         goto error_disable_reg;
 405
 406                 st->vref_mv = ret / 1000;
 407         } else {
 408                 /* Any other error indicates that the regulator does exist */
 409                 if (PTR_ERR(st->reg) != -ENODEV)
 410                         return PTR_ERR(st->reg);
 411                 /* Use internal reference */
 412                 st->vref_mv = 2500;
 413         }
 414
 415         if (pdata) {
 416                 st->fixed_addr = pdata->fixed_addr;
 417                 st->mode = pdata->mode;
 418                 st->range = pdata->range;
 419
 420                 if (!st->fixed_addr) {
 421                         for (i = 0; i < ARRAY_SIZE(st->gpios); ++i) {
 422                                 st->gpios[i] = devm_gpiod_get(&spi->dev,
 423                                                       ad7266_gpio_labels[i],
 424                                                       GPIOD_OUT_LOW);
 425                                 if (IS_ERR(st->gpios[i])) {
 426                                         ret = PTR_ERR(st->gpios[i]);
 427                                         goto error_disable_reg;
 428                                 }
 429                         }
 430                 }
 431         } else {
 432                 st->fixed_addr = true;
 433                 st->range = AD7266_RANGE_VREF;
 434                 st->mode = AD7266_MODE_DIFF;
 435         }
 436
 437         spi_set_drvdata(spi, indio_dev);
 438         st->spi = spi;
 439
 440         indio_dev->dev.parent = &spi->dev;
 441         indio_dev->dev.of_node = spi->dev.of_node;
 442         indio_dev->name = spi_get_device_id(spi)->name;
 443         indio_dev->modes = INDIO_DIRECT_MODE;
 444         indio_dev->info = &ad7266_info;
 445
 446         ad7266_init_channels(indio_dev);
 447
 448         /* wakeup */
 449         st->single_xfer[0].rx_buf = &st->data.sample[0];
 450         st->single_xfer[0].len = 2;
 451         st->single_xfer[0].cs_change = 1;
 452         /* conversion */
 453         st->single_xfer[1].rx_buf = st->data.sample;
 454         st->single_xfer[1].len = 4;
 455         st->single_xfer[1].cs_change = 1;
 456         /* powerdown */
 457         st->single_xfer[2].tx_buf = &st->data.sample[0];
 458         st->single_xfer[2].len = 1;
 459
 460         spi_message_init(&st->single_msg);
 461         spi_message_add_tail(&st->single_xfer[0], &st->single_msg);
 462         spi_message_add_tail(&st->single_xfer[1], &st->single_msg);
 463         spi_message_add_tail(&st->single_xfer[2], &st->single_msg);
 464
 465         ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
 466                 &ad7266_trigger_handler, &iio_triggered_buffer_setup_ops);
 467         if (ret)
 468                 goto error_disable_reg;
 469
 470         ret = iio_device_register(indio_dev);
 471         if (ret)
 472                 goto error_buffer_cleanup;
 473
 474         return 0;
 475
 476 error_buffer_cleanup:
 477         iio_triggered_buffer_cleanup(indio_dev);
 478 error_disable_reg:
 479         if (!IS_ERR(st->reg))
 480                 regulator_disable(st->reg);
 481
 482         return ret;
 483 }
 484
 485 static int ad7266_remove(struct spi_device *spi)
 486 {
 487         struct iio_dev *indio_dev = spi_get_drvdata(spi);
 488         struct ad7266_state *st = iio_priv(indio_dev);
 489
 490         iio_device_unregister(indio_dev);
 491         iio_triggered_buffer_cleanup(indio_dev);
 492         if (!IS_ERR(st->reg))
 493                 regulator_disable(st->reg);
 494
 495         return 0;
 496 }
 497
 498 static const struct spi_device_id ad7266_id[] = {
 499         {"ad7265", 0},
 500         {"ad7266", 0},
 501         { }
 502 };
 503 MODULE_DEVICE_TABLE(spi, ad7266_id);
 504
 505 static struct spi_driver ad7266_driver = {
 506         .driver = {
 507                 .name   = "ad7266",
 508         },
 509         .probe          = ad7266_probe,
 510         .remove         = ad7266_remove,
 511         .id_table       = ad7266_id,
 512 };
 513 module_spi_driver(ad7266_driver);
 514
 515 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
 516 MODULE_DESCRIPTION("Analog Devices AD7266/65 ADC");
 517 MODULE_LICENSE("GPL v2");