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) \
 210         AD_SD_CHANNEL(1, 0, 0, bits, 32, (wordsize) - (bits))
 211 #define AD7170_CHANNEL(bits, wordsize) \
 212         AD_SD_CHANNEL_NO_SAMP_FREQ(1, 0, 0, bits, 32, (wordsize) - (bits))
 213
 214 static const struct ad7780_chip_info ad7780_chip_info_tbl[] = {
 215         [ID_AD7170] = {
 216                 .channel = AD7170_CHANNEL(12, 24),
 217                 .pattern = AD7170_PATTERN_GOOD,
 218                 .pattern_mask = AD7170_PATTERN_MASK,
 219                 .is_ad778x = false,
 220         },
 221         [ID_AD7171] = {
 222                 .channel = AD7170_CHANNEL(16, 24),
 223                 .pattern = AD7170_PATTERN_GOOD,
 224                 .pattern_mask = AD7170_PATTERN_MASK,
 225                 .is_ad778x = false,
 226         },
 227         [ID_AD7780] = {
 228                 .channel = AD7780_CHANNEL(24, 32),
 229                 .pattern = AD7780_PATTERN_GOOD,
 230                 .pattern_mask = AD7780_PATTERN_MASK,
 231                 .is_ad778x = true,
 232         },
 233         [ID_AD7781] = {
 234                 .channel = AD7780_CHANNEL(20, 32),
 235                 .pattern = AD7780_PATTERN_GOOD,
 236                 .pattern_mask = AD7780_PATTERN_MASK,
 237                 .is_ad778x = true,
 238         },
 239 };
 240
 241 static const struct iio_info ad7780_info = {
 242         .read_raw = ad7780_read_raw,
 243         .write_raw = ad7780_write_raw,
 244 };
 245
 246 static int ad7780_init_gpios(struct device *dev, struct ad7780_state *st)
 247 {
 248         int ret;
 249
 250         st->powerdown_gpio = devm_gpiod_get_optional(dev,
 251                                                      "powerdown",
 252                                                      GPIOD_OUT_LOW);
 253         if (IS_ERR(st->powerdown_gpio)) {
 254                 ret = PTR_ERR(st->powerdown_gpio);
 255                 dev_err(dev, "Failed to request powerdown GPIO: %d\n", ret);
 256                 return ret;
 257         }
 258
 259         if (!st->chip_info->is_ad778x)
 260                 return 0;
 261
 262
 263         st->gain_gpio = devm_gpiod_get_optional(dev,
 264                                                 "adi,gain",
 265                                                 GPIOD_OUT_HIGH);
 266         if (IS_ERR(st->gain_gpio)) {
 267                 ret = PTR_ERR(st->gain_gpio);
 268                 dev_err(dev, "Failed to request gain GPIO: %d\n", ret);
 269                 return ret;
 270         }
 271
 272         st->filter_gpio = devm_gpiod_get_optional(dev,
 273                                                   "adi,filter",
 274                                                   GPIOD_OUT_HIGH);
 275         if (IS_ERR(st->filter_gpio)) {
 276                 ret = PTR_ERR(st->filter_gpio);
 277                 dev_err(dev, "Failed to request filter GPIO: %d\n", ret);
 278                 return ret;
 279         }
 280
 281         return 0;
 282 }
 283
 284 static int ad7780_probe(struct spi_device *spi)
 285 {
 286         struct ad7780_state *st;
 287         struct iio_dev *indio_dev;
 288         int ret;
 289
 290         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
 291         if (!indio_dev)
 292                 return -ENOMEM;
 293
 294         st = iio_priv(indio_dev);
 295         st->gain = 1;
 296
 297         ad_sd_init(&st->sd, indio_dev, spi, &ad7780_sigma_delta_info);
 298
 299         st->chip_info =
 300                 &ad7780_chip_info_tbl[spi_get_device_id(spi)->driver_data];
 301
 302         spi_set_drvdata(spi, indio_dev);
 303
 304         indio_dev->dev.parent = &spi->dev;
 305         indio_dev->name = spi_get_device_id(spi)->name;
 306         indio_dev->modes = INDIO_DIRECT_MODE;
 307         indio_dev->channels = &st->chip_info->channel;
 308         indio_dev->num_channels = 1;
 309         indio_dev->info = &ad7780_info;
 310
 311         ret = ad7780_init_gpios(&spi->dev, st);
 312         if (ret)
 313                 goto error_cleanup_buffer_and_trigger;
 314
 315         st->reg = devm_regulator_get(&spi->dev, "avdd");
 316         if (IS_ERR(st->reg))
 317                 return PTR_ERR(st->reg);
 318
 319         ret = regulator_enable(st->reg);
 320         if (ret) {
 321                 dev_err(&spi->dev, "Failed to enable specified AVdd supply\n");
 322                 return ret;
 323         }
 324
 325         ret = ad_sd_setup_buffer_and_trigger(indio_dev);
 326         if (ret)
 327                 goto error_disable_reg;
 328
 329         ret = iio_device_register(indio_dev);
 330         if (ret)
 331                 goto error_cleanup_buffer_and_trigger;
 332
 333         return 0;
 334
 335 error_cleanup_buffer_and_trigger:
 336         ad_sd_cleanup_buffer_and_trigger(indio_dev);
 337 error_disable_reg:
 338         regulator_disable(st->reg);
 339
 340         return ret;
 341 }
 342
 343 static int ad7780_remove(struct spi_device *spi)
 344 {
 345         struct iio_dev *indio_dev = spi_get_drvdata(spi);
 346         struct ad7780_state *st = iio_priv(indio_dev);
 347
 348         iio_device_unregister(indio_dev);
 349         ad_sd_cleanup_buffer_and_trigger(indio_dev);
 350
 351         regulator_disable(st->reg);
 352
 353         return 0;
 354 }
 355
 356 static const struct spi_device_id ad7780_id[] = {
 357         {"ad7170", ID_AD7170},
 358         {"ad7171", ID_AD7171},
 359         {"ad7780", ID_AD7780},
 360         {"ad7781", ID_AD7781},
 361         {}
 362 };
 363 MODULE_DEVICE_TABLE(spi, ad7780_id);
 364
 365 static struct spi_driver ad7780_driver = {
 366         .driver = {
 367                 .name   = "ad7780",
 368         },
 369         .probe          = ad7780_probe,
 370         .remove         = ad7780_remove,
 371         .id_table       = ad7780_id,
 372 };
 373 module_spi_driver(ad7780_driver);
 374
 375 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
 376 MODULE_DESCRIPTION("Analog Devices AD7780 and similar ADCs");
 377 MODULE_LICENSE("GPL v2");