drivers/iio/adc/ad7780.c

   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
  49 static const unsigned int ad778x_gain[2]      = { 1, 128 };
  50 static const unsigned int ad778x_odr_avail[2] = { 10000, 16700 };
  51
  52 struct ad7780_chip_info {
  53         struct iio_chan_spec    channel;
  54         unsigned int            pattern_mask;
  55         unsigned int            pattern;
  56         bool                    is_ad778x;
  57 };
  58
  59 struct 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
  72 enum ad7780_supported_device_ids {
  73         ID_AD7170,
  74         ID_AD7171,
  75         ID_AD7780,
  76         ID_AD7781,
  77 };
  78
  79 static 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
  84 static 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
 105 static 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
 139 static 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
 184 static 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
 202 static 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
 233 static 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
 260 static const struct iio_info ad7780_info = {
 261         .read_raw = ad7780_read_raw,
 262         .write_raw = ad7780_write_raw,
 263 };
 264
 265 static 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
 303 static int ad7780_probe(struct spi_device *spi)
 304 {
 305         struct ad7780_state *st;
 306         struct iio_dev *indio_dev;
 307         int ret;
 308
 309         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
 310         if (!indio_dev)
 311                 return -ENOMEM;
 312
 313         st = iio_priv(indio_dev);
 314         st->gain = 1;
 315
 316         ad_sd_init(&st->sd, indio_dev, spi, &ad7780_sigma_delta_info);
 317
 318         st->chip_info =
 319                 &ad7780_chip_info_tbl[spi_get_device_id(spi)->driver_data];
 320
 321         spi_set_drvdata(spi, indio_dev);
 322
 323         indio_dev->name = spi_get_device_id(spi)->name;
 324         indio_dev->modes = INDIO_DIRECT_MODE;
 325         indio_dev->channels = &st->chip_info->channel;
 326         indio_dev->num_channels = 1;
 327         indio_dev->info = &ad7780_info;
 328
 329         ret = ad7780_init_gpios(&spi->dev, st);
 330         if (ret)
 331                 return ret;
 332
 333         st->reg = devm_regulator_get(&spi->dev, "avdd");
 334         if (IS_ERR(st->reg))
 335                 return PTR_ERR(st->reg);
 336
 337         ret = regulator_enable(st->reg);
 338         if (ret) {
 339                 dev_err(&spi->dev, "Failed to enable specified AVdd supply\n");
 340                 return ret;
 341         }
 342
 343         ret = ad_sd_setup_buffer_and_trigger(indio_dev);
 344         if (ret)
 345                 goto error_disable_reg;
 346
 347         ret = iio_device_register(indio_dev);
 348         if (ret)
 349                 goto error_cleanup_buffer_and_trigger;
 350
 351         return 0;
 352
 353 error_cleanup_buffer_and_trigger:
 354         ad_sd_cleanup_buffer_and_trigger(indio_dev);
 355 error_disable_reg:
 356         regulator_disable(st->reg);
 357
 358         return ret;
 359 }
 360
 361 static int ad7780_remove(struct spi_device *spi)
 362 {
 363         struct iio_dev *indio_dev = spi_get_drvdata(spi);
 364         struct ad7780_state *st = iio_priv(indio_dev);
 365
 366         iio_device_unregister(indio_dev);
 367         ad_sd_cleanup_buffer_and_trigger(indio_dev);
 368
 369         regulator_disable(st->reg);
 370
 371         return 0;
 372 }
 373
 374 static const struct spi_device_id ad7780_id[] = {
 375         {"ad7170", ID_AD7170},
 376         {"ad7171", ID_AD7171},
 377         {"ad7780", ID_AD7780},
 378         {"ad7781", ID_AD7781},
 379         {}
 380 };
 381 MODULE_DEVICE_TABLE(spi, ad7780_id);
 382
 383 static struct spi_driver ad7780_driver = {
 384         .driver = {
 385                 .name   = "ad7780",
 386         },
 387         .probe          = ad7780_probe,
 388         .remove         = ad7780_remove,
 389         .id_table       = ad7780_id,
 390 };
 391 module_spi_driver(ad7780_driver);
 392
 393 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
 394 MODULE_DESCRIPTION("Analog Devices AD7780 and similar ADCs");
 395 MODULE_LICENSE("GPL v2");