linux/drivers/iio/adc/ad7780.c
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   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * AD7170/AD7171 and AD7780/AD7781 SPI ADC driver
   4 *
   5 * Copyright 2011 Analog Devices Inc.
   6 * Copyright 2019 Renato Lui Geh
   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/gpio/consumer.h>
  19#include <linux/module.h>
  20#include <linux/bits.h>
  21
  22#include <linux/iio/iio.h>
  23#include <linux/iio/sysfs.h>
  24#include <linux/iio/adc/ad_sigma_delta.h>
  25
  26#define AD7780_RDY              BIT(7)
  27#define AD7780_FILTER           BIT(6)
  28#define AD7780_ERR              BIT(5)
  29#define AD7780_ID1              BIT(4)
  30#define AD7780_ID0              BIT(3)
  31#define AD7780_GAIN             BIT(2)
  32
  33#define AD7170_ID               0
  34#define AD7171_ID               1
  35#define AD7780_ID               1
  36#define AD7781_ID               0
  37
  38#define AD7780_ID_MASK          (AD7780_ID0 | AD7780_ID1)
  39
  40#define AD7780_PATTERN_GOOD     1
  41#define AD7780_PATTERN_MASK     GENMASK(1, 0)
  42
  43#define AD7170_PATTERN_GOOD     5
  44#define AD7170_PATTERN_MASK     GENMASK(2, 0)
  45
  46#define AD7780_GAIN_MIDPOINT    64
  47#define AD7780_FILTER_MIDPOINT  13350
  48
  49static const unsigned int ad778x_gain[2]      = { 1, 128 };
  50static const unsigned int ad778x_odr_avail[2] = { 10000, 16700 };
  51
  52struct ad7780_chip_info {
  53        struct iio_chan_spec    channel;
  54        unsigned int            pattern_mask;
  55        unsigned int            pattern;
  56        bool                    is_ad778x;
  57};
  58
  59struct ad7780_state {
  60        const struct ad7780_chip_info   *chip_info;
  61        struct regulator                *reg;
  62        struct gpio_desc                *powerdown_gpio;
  63        struct gpio_desc                *gain_gpio;
  64        struct gpio_desc                *filter_gpio;
  65        unsigned int                    gain;
  66        unsigned int                    odr;
  67        unsigned int                    int_vref_mv;
  68
  69        struct ad_sigma_delta sd;
  70};
  71
  72enum ad7780_supported_device_ids {
  73        ID_AD7170,
  74        ID_AD7171,
  75        ID_AD7780,
  76        ID_AD7781,
  77};
  78
  79static struct ad7780_state *ad_sigma_delta_to_ad7780(struct ad_sigma_delta *sd)
  80{
  81        return container_of(sd, struct ad7780_state, sd);
  82}
  83
  84static int ad7780_set_mode(struct ad_sigma_delta *sigma_delta,
  85                           enum ad_sigma_delta_mode mode)
  86{
  87        struct ad7780_state *st = ad_sigma_delta_to_ad7780(sigma_delta);
  88        unsigned int val;
  89
  90        switch (mode) {
  91        case AD_SD_MODE_SINGLE:
  92        case AD_SD_MODE_CONTINUOUS:
  93                val = 1;
  94                break;
  95        default:
  96                val = 0;
  97                break;
  98        }
  99
 100        gpiod_set_value(st->powerdown_gpio, val);
 101
 102        return 0;
 103}
 104
 105static int ad7780_read_raw(struct iio_dev *indio_dev,
 106                           struct iio_chan_spec const *chan,
 107                           int *val,
 108                           int *val2,
 109                           long m)
 110{
 111        struct ad7780_state *st = iio_priv(indio_dev);
 112        int voltage_uv;
 113
 114        switch (m) {
 115        case IIO_CHAN_INFO_RAW:
 116                return ad_sigma_delta_single_conversion(indio_dev, chan, val);
 117        case IIO_CHAN_INFO_SCALE:
 118                voltage_uv = regulator_get_voltage(st->reg);
 119                if (voltage_uv < 0)
 120                        return voltage_uv;
 121                voltage_uv /= 1000;
 122                *val = voltage_uv * st->gain;
 123                *val2 = chan->scan_type.realbits - 1;
 124                st->int_vref_mv = voltage_uv;
 125                return IIO_VAL_FRACTIONAL_LOG2;
 126        case IIO_CHAN_INFO_OFFSET:
 127                *val = -(1 << (chan->scan_type.realbits - 1));
 128                return IIO_VAL_INT;
 129        case IIO_CHAN_INFO_SAMP_FREQ:
 130                *val = st->odr;
 131                return IIO_VAL_INT;
 132        default:
 133                break;
 134        }
 135
 136        return -EINVAL;
 137}
 138
 139static int ad7780_write_raw(struct iio_dev *indio_dev,
 140                            struct iio_chan_spec const *chan,
 141                            int val,
 142                            int val2,
 143                            long m)
 144{
 145        struct ad7780_state *st = iio_priv(indio_dev);
 146        const struct ad7780_chip_info *chip_info = st->chip_info;
 147        unsigned long long vref;
 148        unsigned int full_scale, gain;
 149
 150        if (!chip_info->is_ad778x)
 151                return -EINVAL;
 152
 153        switch (m) {
 154        case IIO_CHAN_INFO_SCALE:
 155                if (val != 0)
 156                        return -EINVAL;
 157
 158                vref = st->int_vref_mv * 1000000LL;
 159                full_scale = 1 << (chip_info->channel.scan_type.realbits - 1);
 160                gain = DIV_ROUND_CLOSEST_ULL(vref, full_scale);
 161                gain = DIV_ROUND_CLOSEST(gain, val2);
 162                st->gain = gain;
 163                if (gain < AD7780_GAIN_MIDPOINT)
 164                        gain = 0;
 165                else
 166                        gain = 1;
 167                gpiod_set_value(st->gain_gpio, gain);
 168                break;
 169        case IIO_CHAN_INFO_SAMP_FREQ:
 170                if (1000*val + val2/1000 < AD7780_FILTER_MIDPOINT)
 171                        val = 0;
 172                else
 173                        val = 1;
 174                st->odr = ad778x_odr_avail[val];
 175                gpiod_set_value(st->filter_gpio, val);
 176                break;
 177        default:
 178                break;
 179        }
 180
 181        return 0;
 182}
 183
 184static int ad7780_postprocess_sample(struct ad_sigma_delta *sigma_delta,
 185                                     unsigned int raw_sample)
 186{
 187        struct ad7780_state *st = ad_sigma_delta_to_ad7780(sigma_delta);
 188        const struct ad7780_chip_info *chip_info = st->chip_info;
 189
 190        if ((raw_sample & AD7780_ERR) ||
 191            ((raw_sample & chip_info->pattern_mask) != chip_info->pattern))
 192                return -EIO;
 193
 194        if (chip_info->is_ad778x) {
 195                st->gain = ad778x_gain[raw_sample & AD7780_GAIN];
 196                st->odr = ad778x_odr_avail[raw_sample & AD7780_FILTER];
 197        }
 198
 199        return 0;
 200}
 201
 202static const struct ad_sigma_delta_info ad7780_sigma_delta_info = {
 203        .set_mode = ad7780_set_mode,
 204        .postprocess_sample = ad7780_postprocess_sample,
 205        .has_registers = false,
 206        .irq_flags = IRQF_TRIGGER_LOW,
 207};
 208
 209#define _AD7780_CHANNEL(_bits, _wordsize, _mask_all)            \
 210{                                                               \
 211        .type = IIO_VOLTAGE,                                    \
 212        .indexed = 1,                                           \
 213        .channel = 0,                                           \
 214        .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |          \
 215                BIT(IIO_CHAN_INFO_OFFSET),                      \
 216        .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),   \
 217        .info_mask_shared_by_all = _mask_all,                   \
 218        .scan_index = 1,                                        \
 219        .scan_type = {                                          \
 220                .sign = 'u',                                    \
 221                .realbits = (_bits),                            \
 222                .storagebits = 32,                              \
 223                .shift = (_wordsize) - (_bits),                 \
 224                .endianness = IIO_BE,                           \
 225        },                                                      \
 226}
 227
 228#define AD7780_CHANNEL(_bits, _wordsize)        \
 229        _AD7780_CHANNEL(_bits, _wordsize, BIT(IIO_CHAN_INFO_SAMP_FREQ))
 230#define AD7170_CHANNEL(_bits, _wordsize)        \
 231        _AD7780_CHANNEL(_bits, _wordsize, 0)
 232
 233static const struct ad7780_chip_info ad7780_chip_info_tbl[] = {
 234        [ID_AD7170] = {
 235                .channel = AD7170_CHANNEL(12, 24),
 236                .pattern = AD7170_PATTERN_GOOD,
 237                .pattern_mask = AD7170_PATTERN_MASK,
 238                .is_ad778x = false,
 239        },
 240        [ID_AD7171] = {
 241                .channel = AD7170_CHANNEL(16, 24),
 242                .pattern = AD7170_PATTERN_GOOD,
 243                .pattern_mask = AD7170_PATTERN_MASK,
 244                .is_ad778x = false,
 245        },
 246        [ID_AD7780] = {
 247                .channel = AD7780_CHANNEL(24, 32),
 248                .pattern = AD7780_PATTERN_GOOD,
 249                .pattern_mask = AD7780_PATTERN_MASK,
 250                .is_ad778x = true,
 251        },
 252        [ID_AD7781] = {
 253                .channel = AD7780_CHANNEL(20, 32),
 254                .pattern = AD7780_PATTERN_GOOD,
 255                .pattern_mask = AD7780_PATTERN_MASK,
 256                .is_ad778x = true,
 257        },
 258};
 259
 260static const struct iio_info ad7780_info = {
 261        .read_raw = ad7780_read_raw,
 262        .write_raw = ad7780_write_raw,
 263};
 264
 265static int ad7780_init_gpios(struct device *dev, struct ad7780_state *st)
 266{
 267        int ret;
 268
 269        st->powerdown_gpio = devm_gpiod_get_optional(dev,
 270                                                     "powerdown",
 271                                                     GPIOD_OUT_LOW);
 272        if (IS_ERR(st->powerdown_gpio)) {
 273                ret = PTR_ERR(st->powerdown_gpio);
 274                dev_err(dev, "Failed to request powerdown GPIO: %d\n", ret);
 275                return ret;
 276        }
 277
 278        if (!st->chip_info->is_ad778x)
 279                return 0;
 280
 281
 282        st->gain_gpio = devm_gpiod_get_optional(dev,
 283                                                "adi,gain",
 284                                                GPIOD_OUT_HIGH);
 285        if (IS_ERR(st->gain_gpio)) {
 286                ret = PTR_ERR(st->gain_gpio);
 287                dev_err(dev, "Failed to request gain GPIO: %d\n", ret);
 288                return ret;
 289        }
 290
 291        st->filter_gpio = devm_gpiod_get_optional(dev,
 292                                                  "adi,filter",
 293                                                  GPIOD_OUT_HIGH);
 294        if (IS_ERR(st->filter_gpio)) {
 295                ret = PTR_ERR(st->filter_gpio);
 296                dev_err(dev, "Failed to request filter GPIO: %d\n", ret);
 297                return ret;
 298        }
 299
 300        return 0;
 301}
 302
 303static void ad7780_reg_disable(void *reg)
 304{
 305        regulator_disable(reg);
 306}
 307
 308static int ad7780_probe(struct spi_device *spi)
 309{
 310        struct ad7780_state *st;
 311        struct iio_dev *indio_dev;
 312        int ret;
 313
 314        indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
 315        if (!indio_dev)
 316                return -ENOMEM;
 317
 318        st = iio_priv(indio_dev);
 319        st->gain = 1;
 320
 321        ad_sd_init(&st->sd, indio_dev, spi, &ad7780_sigma_delta_info);
 322
 323        st->chip_info =
 324                &ad7780_chip_info_tbl[spi_get_device_id(spi)->driver_data];
 325
 326        indio_dev->name = spi_get_device_id(spi)->name;
 327        indio_dev->modes = INDIO_DIRECT_MODE;
 328        indio_dev->channels = &st->chip_info->channel;
 329        indio_dev->num_channels = 1;
 330        indio_dev->info = &ad7780_info;
 331
 332        ret = ad7780_init_gpios(&spi->dev, st);
 333        if (ret)
 334                return ret;
 335
 336        st->reg = devm_regulator_get(&spi->dev, "avdd");
 337        if (IS_ERR(st->reg))
 338                return PTR_ERR(st->reg);
 339
 340        ret = regulator_enable(st->reg);
 341        if (ret) {
 342                dev_err(&spi->dev, "Failed to enable specified AVdd supply\n");
 343                return ret;
 344        }
 345
 346        ret = devm_add_action_or_reset(&spi->dev, ad7780_reg_disable, st->reg);
 347        if (ret)
 348                return ret;
 349
 350        ret = devm_ad_sd_setup_buffer_and_trigger(&spi->dev, indio_dev);
 351        if (ret)
 352                return ret;
 353
 354        return devm_iio_device_register(&spi->dev, indio_dev);
 355}
 356
 357static const struct spi_device_id ad7780_id[] = {
 358        {"ad7170", ID_AD7170},
 359        {"ad7171", ID_AD7171},
 360        {"ad7780", ID_AD7780},
 361        {"ad7781", ID_AD7781},
 362        {}
 363};
 364MODULE_DEVICE_TABLE(spi, ad7780_id);
 365
 366static struct spi_driver ad7780_driver = {
 367        .driver = {
 368                .name   = "ad7780",
 369        },
 370        .probe          = ad7780_probe,
 371        .id_table       = ad7780_id,
 372};
 373module_spi_driver(ad7780_driver);
 374
 375MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
 376MODULE_DESCRIPTION("Analog Devices AD7780 and similar ADCs");
 377MODULE_LICENSE("GPL v2");
 378