drivers/iio/adc/ad7791.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * AD7787/AD7788/AD7789/AD7790/AD7791 SPI ADC driver
   4  *
   5  * Copyright 2012 Analog Devices Inc.
   6  *  Author: Lars-Peter Clausen <lars@metafoo.de>
   7  */
   8
   9 #include <linux/interrupt.h>
  10 #include <linux/device.h>
  11 #include <linux/kernel.h>
  12 #include <linux/slab.h>
  13 #include <linux/sysfs.h>
  14 #include <linux/spi/spi.h>
  15 #include <linux/regulator/consumer.h>
  16 #include <linux/err.h>
  17 #include <linux/sched.h>
  18 #include <linux/delay.h>
  19 #include <linux/module.h>
  20
  21 #include <linux/iio/iio.h>
  22 #include <linux/iio/sysfs.h>
  23 #include <linux/iio/buffer.h>
  24 #include <linux/iio/trigger.h>
  25 #include <linux/iio/trigger_consumer.h>
  26 #include <linux/iio/triggered_buffer.h>
  27 #include <linux/iio/adc/ad_sigma_delta.h>
  28
  29 #include <linux/platform_data/ad7791.h>
  30
  31 #define AD7791_REG_COMM                 0x0 /* For writes */
  32 #define AD7791_REG_STATUS               0x0 /* For reads */
  33 #define AD7791_REG_MODE                 0x1
  34 #define AD7791_REG_FILTER               0x2
  35 #define AD7791_REG_DATA                 0x3
  36
  37 #define AD7791_MODE_CONTINUOUS          0x00
  38 #define AD7791_MODE_SINGLE              0x02
  39 #define AD7791_MODE_POWERDOWN           0x03
  40
  41 #define AD7791_CH_AIN1P_AIN1N           0x00
  42 #define AD7791_CH_AIN2                  0x01
  43 #define AD7791_CH_AIN1N_AIN1N           0x02
  44 #define AD7791_CH_AVDD_MONITOR          0x03
  45
  46 #define AD7791_FILTER_CLK_DIV_1         (0x0 << 4)
  47 #define AD7791_FILTER_CLK_DIV_2         (0x1 << 4)
  48 #define AD7791_FILTER_CLK_DIV_4         (0x2 << 4)
  49 #define AD7791_FILTER_CLK_DIV_8         (0x3 << 4)
  50 #define AD7791_FILTER_CLK_MASK          (0x3 << 4)
  51 #define AD7791_FILTER_RATE_120          0x0
  52 #define AD7791_FILTER_RATE_100          0x1
  53 #define AD7791_FILTER_RATE_33_3         0x2
  54 #define AD7791_FILTER_RATE_20           0x3
  55 #define AD7791_FILTER_RATE_16_6         0x4
  56 #define AD7791_FILTER_RATE_16_7         0x5
  57 #define AD7791_FILTER_RATE_13_3         0x6
  58 #define AD7791_FILTER_RATE_9_5          0x7
  59 #define AD7791_FILTER_RATE_MASK         0x7
  60
  61 #define AD7791_MODE_BUFFER              BIT(1)
  62 #define AD7791_MODE_UNIPOLAR            BIT(2)
  63 #define AD7791_MODE_BURNOUT             BIT(3)
  64 #define AD7791_MODE_SEL_MASK            (0x3 << 6)
  65 #define AD7791_MODE_SEL(x)              ((x) << 6)
  66
  67 #define __AD7991_CHANNEL(_si, _channel1, _channel2, _address, _bits, \
  68         _storagebits, _shift, _extend_name, _type, _mask_all) \
  69         { \
  70                 .type = (_type), \
  71                 .differential = (_channel2 == -1 ? 0 : 1), \
  72                 .indexed = 1, \
  73                 .channel = (_channel1), \
  74                 .channel2 = (_channel2), \
  75                 .address = (_address), \
  76                 .extend_name = (_extend_name), \
  77                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
  78                         BIT(IIO_CHAN_INFO_OFFSET), \
  79                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
  80                 .info_mask_shared_by_all = _mask_all, \
  81                 .scan_index = (_si), \
  82                 .scan_type = { \
  83                         .sign = 'u', \
  84                         .realbits = (_bits), \
  85                         .storagebits = (_storagebits), \
  86                         .shift = (_shift), \
  87                         .endianness = IIO_BE, \
  88                 }, \
  89         }
  90
  91 #define AD7991_SHORTED_CHANNEL(_si, _channel, _address, _bits, \
  92         _storagebits, _shift) \
  93         __AD7991_CHANNEL(_si, _channel, _channel, _address, _bits, \
  94                 _storagebits, _shift, "shorted", IIO_VOLTAGE, \
  95                 BIT(IIO_CHAN_INFO_SAMP_FREQ))
  96
  97 #define AD7991_CHANNEL(_si, _channel, _address, _bits, \
  98         _storagebits, _shift) \
  99         __AD7991_CHANNEL(_si, _channel, -1, _address, _bits, \
 100                 _storagebits, _shift, NULL, IIO_VOLTAGE, \
 101                  BIT(IIO_CHAN_INFO_SAMP_FREQ))
 102
 103 #define AD7991_DIFF_CHANNEL(_si, _channel1, _channel2, _address, _bits, \
 104         _storagebits, _shift) \
 105         __AD7991_CHANNEL(_si, _channel1, _channel2, _address, _bits, \
 106                 _storagebits, _shift, NULL, IIO_VOLTAGE, \
 107                 BIT(IIO_CHAN_INFO_SAMP_FREQ))
 108
 109 #define AD7991_SUPPLY_CHANNEL(_si, _channel, _address, _bits, _storagebits, \
 110         _shift) \
 111         __AD7991_CHANNEL(_si, _channel, -1, _address, _bits, \
 112                 _storagebits, _shift, "supply", IIO_VOLTAGE, \
 113                 BIT(IIO_CHAN_INFO_SAMP_FREQ))
 114
 115 #define DECLARE_AD7787_CHANNELS(name, bits, storagebits) \
 116 const struct iio_chan_spec name[] = { \
 117         AD7991_DIFF_CHANNEL(0, 0, 0, AD7791_CH_AIN1P_AIN1N, \
 118                 (bits), (storagebits), 0), \
 119         AD7991_CHANNEL(1, 1, AD7791_CH_AIN2, (bits), (storagebits), 0), \
 120         AD7991_SHORTED_CHANNEL(2, 0, AD7791_CH_AIN1N_AIN1N, \
 121                 (bits), (storagebits), 0), \
 122         AD7991_SUPPLY_CHANNEL(3, 2, AD7791_CH_AVDD_MONITOR,  \
 123                 (bits), (storagebits), 0), \
 124         IIO_CHAN_SOFT_TIMESTAMP(4), \
 125 }
 126
 127 #define DECLARE_AD7791_CHANNELS(name, bits, storagebits) \
 128 const struct iio_chan_spec name[] = { \
 129         AD7991_DIFF_CHANNEL(0, 0, 0, AD7791_CH_AIN1P_AIN1N, \
 130                 (bits), (storagebits), 0), \
 131         AD7991_SHORTED_CHANNEL(1, 0, AD7791_CH_AIN1N_AIN1N, \
 132                 (bits), (storagebits), 0), \
 133         AD7991_SUPPLY_CHANNEL(2, 1, AD7791_CH_AVDD_MONITOR, \
 134                 (bits), (storagebits), 0), \
 135         IIO_CHAN_SOFT_TIMESTAMP(3), \
 136 }
 137
 138 static DECLARE_AD7787_CHANNELS(ad7787_channels, 24, 32);
 139 static DECLARE_AD7791_CHANNELS(ad7790_channels, 16, 16);
 140 static DECLARE_AD7791_CHANNELS(ad7791_channels, 24, 32);
 141
 142 enum {
 143         AD7787,
 144         AD7788,
 145         AD7789,
 146         AD7790,
 147         AD7791,
 148 };
 149
 150 enum ad7791_chip_info_flags {
 151         AD7791_FLAG_HAS_FILTER          = (1 << 0),
 152         AD7791_FLAG_HAS_BUFFER          = (1 << 1),
 153         AD7791_FLAG_HAS_UNIPOLAR        = (1 << 2),
 154         AD7791_FLAG_HAS_BURNOUT         = (1 << 3),
 155 };
 156
 157 struct ad7791_chip_info {
 158         const struct iio_chan_spec *channels;
 159         unsigned int num_channels;
 160         enum ad7791_chip_info_flags flags;
 161 };
 162
 163 static const struct ad7791_chip_info ad7791_chip_infos[] = {
 164         [AD7787] = {
 165                 .channels = ad7787_channels,
 166                 .num_channels = ARRAY_SIZE(ad7787_channels),
 167                 .flags = AD7791_FLAG_HAS_FILTER | AD7791_FLAG_HAS_BUFFER |
 168                         AD7791_FLAG_HAS_UNIPOLAR | AD7791_FLAG_HAS_BURNOUT,
 169         },
 170         [AD7788] = {
 171                 .channels = ad7790_channels,
 172                 .num_channels = ARRAY_SIZE(ad7790_channels),
 173                 .flags = AD7791_FLAG_HAS_UNIPOLAR,
 174         },
 175         [AD7789] = {
 176                 .channels = ad7791_channels,
 177                 .num_channels = ARRAY_SIZE(ad7791_channels),
 178                 .flags = AD7791_FLAG_HAS_UNIPOLAR,
 179         },
 180         [AD7790] = {
 181                 .channels = ad7790_channels,
 182                 .num_channels = ARRAY_SIZE(ad7790_channels),
 183                 .flags = AD7791_FLAG_HAS_FILTER | AD7791_FLAG_HAS_BUFFER |
 184                         AD7791_FLAG_HAS_BURNOUT,
 185         },
 186         [AD7791] = {
 187                 .channels = ad7791_channels,
 188                 .num_channels = ARRAY_SIZE(ad7791_channels),
 189                 .flags = AD7791_FLAG_HAS_FILTER | AD7791_FLAG_HAS_BUFFER |
 190                         AD7791_FLAG_HAS_UNIPOLAR | AD7791_FLAG_HAS_BURNOUT,
 191         },
 192 };
 193
 194 struct ad7791_state {
 195         struct ad_sigma_delta sd;
 196         uint8_t mode;
 197         uint8_t filter;
 198
 199         struct regulator *reg;
 200         const struct ad7791_chip_info *info;
 201 };
 202
 203 static const int ad7791_sample_freq_avail[8][2] = {
 204         [AD7791_FILTER_RATE_120] =  { 120, 0 },
 205         [AD7791_FILTER_RATE_100] =  { 100, 0 },
 206         [AD7791_FILTER_RATE_33_3] = { 33,  300000 },
 207         [AD7791_FILTER_RATE_20] =   { 20,  0 },
 208         [AD7791_FILTER_RATE_16_6] = { 16,  600000 },
 209         [AD7791_FILTER_RATE_16_7] = { 16,  700000 },
 210         [AD7791_FILTER_RATE_13_3] = { 13,  300000 },
 211         [AD7791_FILTER_RATE_9_5] =  { 9,   500000 },
 212 };
 213
 214 static struct ad7791_state *ad_sigma_delta_to_ad7791(struct ad_sigma_delta *sd)
 215 {
 216         return container_of(sd, struct ad7791_state, sd);
 217 }
 218
 219 static int ad7791_set_channel(struct ad_sigma_delta *sd, unsigned int channel)
 220 {
 221         ad_sd_set_comm(sd, channel);
 222
 223         return 0;
 224 }
 225
 226 static int ad7791_set_mode(struct ad_sigma_delta *sd,
 227         enum ad_sigma_delta_mode mode)
 228 {
 229         struct ad7791_state *st = ad_sigma_delta_to_ad7791(sd);
 230
 231         switch (mode) {
 232         case AD_SD_MODE_CONTINUOUS:
 233                 mode = AD7791_MODE_CONTINUOUS;
 234                 break;
 235         case AD_SD_MODE_SINGLE:
 236                 mode = AD7791_MODE_SINGLE;
 237                 break;
 238         case AD_SD_MODE_IDLE:
 239         case AD_SD_MODE_POWERDOWN:
 240                 mode = AD7791_MODE_POWERDOWN;
 241                 break;
 242         }
 243
 244         st->mode &= ~AD7791_MODE_SEL_MASK;
 245         st->mode |= AD7791_MODE_SEL(mode);
 246
 247         return ad_sd_write_reg(sd, AD7791_REG_MODE, sizeof(st->mode), st->mode);
 248 }
 249
 250 static const struct ad_sigma_delta_info ad7791_sigma_delta_info = {
 251         .set_channel = ad7791_set_channel,
 252         .set_mode = ad7791_set_mode,
 253         .has_registers = true,
 254         .addr_shift = 4,
 255         .read_mask = BIT(3),
 256         .irq_flags = IRQF_TRIGGER_FALLING,
 257 };
 258
 259 static int ad7791_read_raw(struct iio_dev *indio_dev,
 260         const struct iio_chan_spec *chan, int *val, int *val2, long info)
 261 {
 262         struct ad7791_state *st = iio_priv(indio_dev);
 263         bool unipolar = !!(st->mode & AD7791_MODE_UNIPOLAR);
 264         unsigned int rate;
 265
 266         switch (info) {
 267         case IIO_CHAN_INFO_RAW:
 268                 return ad_sigma_delta_single_conversion(indio_dev, chan, val);
 269         case IIO_CHAN_INFO_OFFSET:
 270                 /**
 271                  * Unipolar: 0 to VREF
 272                  * Bipolar -VREF to VREF
 273                  **/
 274                 if (unipolar)
 275                         *val = 0;
 276                 else
 277                         *val = -(1 << (chan->scan_type.realbits - 1));
 278                 return IIO_VAL_INT;
 279         case IIO_CHAN_INFO_SCALE:
 280                 /* The monitor channel uses an internal reference. */
 281                 if (chan->address == AD7791_CH_AVDD_MONITOR) {
 282                         /*
 283                          * The signal is attenuated by a factor of 5 and
 284                          * compared against a 1.17V internal reference.
 285                          */
 286                         *val = 1170 * 5;
 287                 } else {
 288                         int voltage_uv;
 289
 290                         voltage_uv = regulator_get_voltage(st->reg);
 291                         if (voltage_uv < 0)
 292                                 return voltage_uv;
 293
 294                         *val = voltage_uv / 1000;
 295                 }
 296                 if (unipolar)
 297                         *val2 = chan->scan_type.realbits;
 298                 else
 299                         *val2 = chan->scan_type.realbits - 1;
 300
 301                 return IIO_VAL_FRACTIONAL_LOG2;
 302         case IIO_CHAN_INFO_SAMP_FREQ:
 303                 rate = st->filter & AD7791_FILTER_RATE_MASK;
 304                 *val = ad7791_sample_freq_avail[rate][0];
 305                 *val2 = ad7791_sample_freq_avail[rate][1];
 306                 return IIO_VAL_INT_PLUS_MICRO;
 307         }
 308
 309         return -EINVAL;
 310 }
 311
 312 static int ad7791_write_raw(struct iio_dev *indio_dev,
 313         struct iio_chan_spec const *chan, int val, int val2, long mask)
 314 {
 315         struct ad7791_state *st = iio_priv(indio_dev);
 316         int ret, i;
 317
 318         ret = iio_device_claim_direct_mode(indio_dev);
 319         if (ret)
 320                 return ret;
 321
 322         switch (mask) {
 323         case IIO_CHAN_INFO_SAMP_FREQ:
 324                 for (i = 0; i < ARRAY_SIZE(ad7791_sample_freq_avail); i++) {
 325                         if (ad7791_sample_freq_avail[i][0] == val &&
 326                             ad7791_sample_freq_avail[i][1] == val2)
 327                                 break;
 328                 }
 329
 330                 if (i == ARRAY_SIZE(ad7791_sample_freq_avail)) {
 331                         ret = -EINVAL;
 332                         break;
 333                 }
 334
 335                 st->filter &= ~AD7791_FILTER_RATE_MASK;
 336                 st->filter |= i;
 337                 ad_sd_write_reg(&st->sd, AD7791_REG_FILTER,
 338                                 sizeof(st->filter),
 339                                 st->filter);
 340                 break;
 341         default:
 342                 ret = -EINVAL;
 343         }
 344
 345         iio_device_release_direct_mode(indio_dev);
 346         return ret;
 347 }
 348
 349 static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("120 100 33.3 20 16.7 16.6 13.3 9.5");
 350
 351 static struct attribute *ad7791_attributes[] = {
 352         &iio_const_attr_sampling_frequency_available.dev_attr.attr,
 353         NULL
 354 };
 355
 356 static const struct attribute_group ad7791_attribute_group = {
 357         .attrs = ad7791_attributes,
 358 };
 359
 360 static const struct iio_info ad7791_info = {
 361         .read_raw = &ad7791_read_raw,
 362         .write_raw = &ad7791_write_raw,
 363         .attrs = &ad7791_attribute_group,
 364         .validate_trigger = ad_sd_validate_trigger,
 365 };
 366
 367 static const struct iio_info ad7791_no_filter_info = {
 368         .read_raw = &ad7791_read_raw,
 369         .write_raw = &ad7791_write_raw,
 370         .validate_trigger = ad_sd_validate_trigger,
 371 };
 372
 373 static int ad7791_setup(struct ad7791_state *st,
 374                         const struct ad7791_platform_data *pdata)
 375 {
 376         /* Set to poweron-reset default values */
 377         st->mode = AD7791_MODE_BUFFER;
 378         st->filter = AD7791_FILTER_RATE_16_6;
 379
 380         if (!pdata)
 381                 return 0;
 382
 383         if ((st->info->flags & AD7791_FLAG_HAS_BUFFER) && !pdata->buffered)
 384                 st->mode &= ~AD7791_MODE_BUFFER;
 385
 386         if ((st->info->flags & AD7791_FLAG_HAS_BURNOUT) &&
 387                 pdata->burnout_current)
 388                 st->mode |= AD7791_MODE_BURNOUT;
 389
 390         if ((st->info->flags & AD7791_FLAG_HAS_UNIPOLAR) && pdata->unipolar)
 391                 st->mode |= AD7791_MODE_UNIPOLAR;
 392
 393         return ad_sd_write_reg(&st->sd, AD7791_REG_MODE, sizeof(st->mode),
 394                 st->mode);
 395 }
 396
 397 static void ad7791_reg_disable(void *reg)
 398 {
 399         regulator_disable(reg);
 400 }
 401
 402 static int ad7791_probe(struct spi_device *spi)
 403 {
 404         const struct ad7791_platform_data *pdata = dev_get_platdata(&spi->dev);
 405         struct iio_dev *indio_dev;
 406         struct ad7791_state *st;
 407         int ret;
 408
 409         if (!spi->irq) {
 410                 dev_err(&spi->dev, "Missing IRQ.\n");
 411                 return -ENXIO;
 412         }
 413
 414         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
 415         if (!indio_dev)
 416                 return -ENOMEM;
 417
 418         st = iio_priv(indio_dev);
 419
 420         st->reg = devm_regulator_get(&spi->dev, "refin");
 421         if (IS_ERR(st->reg))
 422                 return PTR_ERR(st->reg);
 423
 424         ret = regulator_enable(st->reg);
 425         if (ret)
 426                 return ret;
 427
 428         ret = devm_add_action_or_reset(&spi->dev, ad7791_reg_disable, st->reg);
 429         if (ret)
 430                 return ret;
 431
 432         st->info = &ad7791_chip_infos[spi_get_device_id(spi)->driver_data];
 433         ad_sd_init(&st->sd, indio_dev, spi, &ad7791_sigma_delta_info);
 434
 435         indio_dev->name = spi_get_device_id(spi)->name;
 436         indio_dev->modes = INDIO_DIRECT_MODE;
 437         indio_dev->channels = st->info->channels;
 438         indio_dev->num_channels = st->info->num_channels;
 439         if (st->info->flags & AD7791_FLAG_HAS_FILTER)
 440                 indio_dev->info = &ad7791_info;
 441         else
 442                 indio_dev->info = &ad7791_no_filter_info;
 443
 444         ret = devm_ad_sd_setup_buffer_and_trigger(&spi->dev, indio_dev);
 445         if (ret)
 446                 return ret;
 447
 448         ret = ad7791_setup(st, pdata);
 449         if (ret)
 450                 return ret;
 451
 452         return devm_iio_device_register(&spi->dev, indio_dev);
 453 }
 454
 455 static const struct spi_device_id ad7791_spi_ids[] = {
 456         { "ad7787", AD7787 },
 457         { "ad7788", AD7788 },
 458         { "ad7789", AD7789 },
 459         { "ad7790", AD7790 },
 460         { "ad7791", AD7791 },
 461         {}
 462 };
 463 MODULE_DEVICE_TABLE(spi, ad7791_spi_ids);
 464
 465 static struct spi_driver ad7791_driver = {
 466         .driver = {
 467                 .name   = "ad7791",
 468         },
 469         .probe          = ad7791_probe,
 470         .id_table       = ad7791_spi_ids,
 471 };
 472 module_spi_driver(ad7791_driver);
 473
 474 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
 475 MODULE_DESCRIPTION("Analog Devices AD7787/AD7788/AD7789/AD7790/AD7791 ADC driver");
 476 MODULE_LICENSE("GPL v2");
 477 MODULE_IMPORT_NS("IIO_AD_SIGMA_DELTA");