drivers/iio/pressure/ms5611_core.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * MS5611 pressure and temperature sensor driver
   4  *
   5  * Copyright (c) Tomasz Duszynski <tduszyns@gmail.com>
   6  *
   7  * Data sheet:
   8  *  http://www.meas-spec.com/downloads/MS5611-01BA03.pdf
   9  *  http://www.meas-spec.com/downloads/MS5607-02BA03.pdf
  10  *
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/iio/iio.h>
  15 #include <linux/delay.h>
  16 #include <linux/regulator/consumer.h>
  17
  18 #include <linux/iio/sysfs.h>
  19 #include <linux/iio/buffer.h>
  20 #include <linux/iio/triggered_buffer.h>
  21 #include <linux/iio/trigger_consumer.h>
  22 #include "ms5611.h"
  23
  24 #define MS5611_INIT_OSR(_cmd, _conv_usec, _rate) \
  25         { .cmd = _cmd, .conv_usec = _conv_usec, .rate = _rate }
  26
  27 static const struct ms5611_osr ms5611_avail_pressure_osr[] = {
  28         MS5611_INIT_OSR(0x40, 600,  256),
  29         MS5611_INIT_OSR(0x42, 1170, 512),
  30         MS5611_INIT_OSR(0x44, 2280, 1024),
  31         MS5611_INIT_OSR(0x46, 4540, 2048),
  32         MS5611_INIT_OSR(0x48, 9040, 4096)
  33 };
  34
  35 static const struct ms5611_osr ms5611_avail_temp_osr[] = {
  36         MS5611_INIT_OSR(0x50, 600,  256),
  37         MS5611_INIT_OSR(0x52, 1170, 512),
  38         MS5611_INIT_OSR(0x54, 2280, 1024),
  39         MS5611_INIT_OSR(0x56, 4540, 2048),
  40         MS5611_INIT_OSR(0x58, 9040, 4096)
  41 };
  42
  43 static const char ms5611_show_osr[] = "256 512 1024 2048 4096";
  44
  45 static IIO_CONST_ATTR(oversampling_ratio_available, ms5611_show_osr);
  46
  47 static struct attribute *ms5611_attributes[] = {
  48         &iio_const_attr_oversampling_ratio_available.dev_attr.attr,
  49         NULL,
  50 };
  51
  52 static const struct attribute_group ms5611_attribute_group = {
  53         .attrs = ms5611_attributes,
  54 };
  55
  56 static bool ms5611_prom_is_valid(u16 *prom, size_t len)
  57 {
  58         int i, j;
  59         uint16_t crc = 0, crc_orig = prom[7] & 0x000F;
  60
  61         prom[7] &= 0xFF00;
  62
  63         for (i = 0; i < len * 2; i++) {
  64                 if (i % 2 == 1)
  65                         crc ^= prom[i >> 1] & 0x00FF;
  66                 else
  67                         crc ^= prom[i >> 1] >> 8;
  68
  69                 for (j = 0; j < 8; j++) {
  70                         if (crc & 0x8000)
  71                                 crc = (crc << 1) ^ 0x3000;
  72                         else
  73                                 crc <<= 1;
  74                 }
  75         }
  76
  77         crc = (crc >> 12) & 0x000F;
  78
  79         return crc == crc_orig;
  80 }
  81
  82 static int ms5611_read_prom(struct iio_dev *indio_dev)
  83 {
  84         int ret, i;
  85         struct ms5611_state *st = iio_priv(indio_dev);
  86
  87         for (i = 0; i < MS5611_PROM_WORDS_NB; i++) {
  88                 ret = st->read_prom_word(st, i, &st->prom[i]);
  89                 if (ret < 0) {
  90                         dev_err(&indio_dev->dev,
  91                                 "failed to read prom at %d\n", i);
  92                         return ret;
  93                 }
  94         }
  95
  96         if (!ms5611_prom_is_valid(st->prom, MS5611_PROM_WORDS_NB)) {
  97                 dev_err(&indio_dev->dev, "PROM integrity check failed\n");
  98                 return -ENODEV;
  99         }
 100
 101         return 0;
 102 }
 103
 104 static int ms5611_read_temp_and_pressure(struct iio_dev *indio_dev,
 105                                          s32 *temp, s32 *pressure)
 106 {
 107         int ret;
 108         struct ms5611_state *st = iio_priv(indio_dev);
 109
 110         ret = st->read_adc_temp_and_pressure(st, temp, pressure);
 111         if (ret < 0) {
 112                 dev_err(&indio_dev->dev,
 113                         "failed to read temperature and pressure\n");
 114                 return ret;
 115         }
 116
 117         return st->compensate_temp_and_pressure(st, temp, pressure);
 118 }
 119
 120 static int ms5611_temp_and_pressure_compensate(struct ms5611_state *st,
 121                                                s32 *temp, s32 *pressure)
 122 {
 123         s32 t = *temp, p = *pressure;
 124         s64 off, sens, dt;
 125
 126         dt = t - (st->prom[5] << 8);
 127         off = ((s64)st->prom[2] << 16) + ((st->prom[4] * dt) >> 7);
 128         sens = ((s64)st->prom[1] << 15) + ((st->prom[3] * dt) >> 8);
 129
 130         t = 2000 + ((st->prom[6] * dt) >> 23);
 131         if (t < 2000) {
 132                 s64 off2, sens2, t2;
 133
 134                 t2 = (dt * dt) >> 31;
 135                 off2 = (5 * (t - 2000) * (t - 2000)) >> 1;
 136                 sens2 = off2 >> 1;
 137
 138                 if (t < -1500) {
 139                         s64 tmp = (t + 1500) * (t + 1500);
 140
 141                         off2 += 7 * tmp;
 142                         sens2 += (11 * tmp) >> 1;
 143                 }
 144
 145                 t -= t2;
 146                 off -= off2;
 147                 sens -= sens2;
 148         }
 149
 150         *temp = t;
 151         *pressure = (((p * sens) >> 21) - off) >> 15;
 152
 153         return 0;
 154 }
 155
 156 static int ms5607_temp_and_pressure_compensate(struct ms5611_state *st,
 157                                                s32 *temp, s32 *pressure)
 158 {
 159         s32 t = *temp, p = *pressure;
 160         s64 off, sens, dt;
 161
 162         dt = t - (st->prom[5] << 8);
 163         off = ((s64)st->prom[2] << 17) + ((st->prom[4] * dt) >> 6);
 164         sens = ((s64)st->prom[1] << 16) + ((st->prom[3] * dt) >> 7);
 165
 166         t = 2000 + ((st->prom[6] * dt) >> 23);
 167         if (t < 2000) {
 168                 s64 off2, sens2, t2, tmp;
 169
 170                 t2 = (dt * dt) >> 31;
 171                 tmp = (t - 2000) * (t - 2000);
 172                 off2 = (61 * tmp) >> 4;
 173                 sens2 = tmp << 1;
 174
 175                 if (t < -1500) {
 176                         tmp = (t + 1500) * (t + 1500);
 177                         off2 += 15 * tmp;
 178                         sens2 += 8 * tmp;
 179                 }
 180
 181                 t -= t2;
 182                 off -= off2;
 183                 sens -= sens2;
 184         }
 185
 186         *temp = t;
 187         *pressure = (((p * sens) >> 21) - off) >> 15;
 188
 189         return 0;
 190 }
 191
 192 static int ms5611_reset(struct iio_dev *indio_dev)
 193 {
 194         int ret;
 195         struct ms5611_state *st = iio_priv(indio_dev);
 196
 197         ret = st->reset(st);
 198         if (ret < 0) {
 199                 dev_err(&indio_dev->dev, "failed to reset device\n");
 200                 return ret;
 201         }
 202
 203         usleep_range(3000, 4000);
 204
 205         return 0;
 206 }
 207
 208 static irqreturn_t ms5611_trigger_handler(int irq, void *p)
 209 {
 210         struct iio_poll_func *pf = p;
 211         struct iio_dev *indio_dev = pf->indio_dev;
 212         struct ms5611_state *st = iio_priv(indio_dev);
 213         /* Ensure buffer elements are naturally aligned */
 214         struct {
 215                 s32 channels[2];
 216                 s64 ts __aligned(8);
 217         } scan;
 218         int ret;
 219
 220         mutex_lock(&st->lock);
 221         ret = ms5611_read_temp_and_pressure(indio_dev, &scan.channels[1],
 222                                             &scan.channels[0]);
 223         mutex_unlock(&st->lock);
 224         if (ret < 0)
 225                 goto err;
 226
 227         iio_push_to_buffers_with_timestamp(indio_dev, &scan,
 228                                            iio_get_time_ns(indio_dev));
 229
 230 err:
 231         iio_trigger_notify_done(indio_dev->trig);
 232
 233         return IRQ_HANDLED;
 234 }
 235
 236 static int ms5611_read_raw(struct iio_dev *indio_dev,
 237                            struct iio_chan_spec const *chan,
 238                            int *val, int *val2, long mask)
 239 {
 240         int ret;
 241         s32 temp, pressure;
 242         struct ms5611_state *st = iio_priv(indio_dev);
 243
 244         switch (mask) {
 245         case IIO_CHAN_INFO_PROCESSED:
 246                 mutex_lock(&st->lock);
 247                 ret = ms5611_read_temp_and_pressure(indio_dev,
 248                                                     &temp, &pressure);
 249                 mutex_unlock(&st->lock);
 250                 if (ret < 0)
 251                         return ret;
 252
 253                 switch (chan->type) {
 254                 case IIO_TEMP:
 255                         *val = temp * 10;
 256                         return IIO_VAL_INT;
 257                 case IIO_PRESSURE:
 258                         *val = pressure / 1000;
 259                         *val2 = (pressure % 1000) * 1000;
 260                         return IIO_VAL_INT_PLUS_MICRO;
 261                 default:
 262                         return -EINVAL;
 263                 }
 264         case IIO_CHAN_INFO_SCALE:
 265                 switch (chan->type) {
 266                 case IIO_TEMP:
 267                         *val = 10;
 268                         return IIO_VAL_INT;
 269                 case IIO_PRESSURE:
 270                         *val = 0;
 271                         *val2 = 1000;
 272                         return IIO_VAL_INT_PLUS_MICRO;
 273                 default:
 274                         return -EINVAL;
 275                 }
 276         case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
 277                 if (chan->type != IIO_TEMP && chan->type != IIO_PRESSURE)
 278                         break;
 279                 mutex_lock(&st->lock);
 280                 if (chan->type == IIO_TEMP)
 281                         *val = (int)st->temp_osr->rate;
 282                 else
 283                         *val = (int)st->pressure_osr->rate;
 284                 mutex_unlock(&st->lock);
 285                 return IIO_VAL_INT;
 286         }
 287
 288         return -EINVAL;
 289 }
 290
 291 static const struct ms5611_osr *ms5611_find_osr(int rate,
 292                                                 const struct ms5611_osr *osr,
 293                                                 size_t count)
 294 {
 295         unsigned int r;
 296
 297         for (r = 0; r < count; r++)
 298                 if ((unsigned short)rate == osr[r].rate)
 299                         break;
 300         if (r >= count)
 301                 return NULL;
 302         return &osr[r];
 303 }
 304
 305 static int ms5611_write_raw(struct iio_dev *indio_dev,
 306                             struct iio_chan_spec const *chan,
 307                             int val, int val2, long mask)
 308 {
 309         struct ms5611_state *st = iio_priv(indio_dev);
 310         const struct ms5611_osr *osr = NULL;
 311         int ret;
 312
 313         if (mask != IIO_CHAN_INFO_OVERSAMPLING_RATIO)
 314                 return -EINVAL;
 315
 316         if (chan->type == IIO_TEMP)
 317                 osr = ms5611_find_osr(val, ms5611_avail_temp_osr,
 318                                       ARRAY_SIZE(ms5611_avail_temp_osr));
 319         else if (chan->type == IIO_PRESSURE)
 320                 osr = ms5611_find_osr(val, ms5611_avail_pressure_osr,
 321                                       ARRAY_SIZE(ms5611_avail_pressure_osr));
 322         if (!osr)
 323                 return -EINVAL;
 324
 325         ret = iio_device_claim_direct_mode(indio_dev);
 326         if (ret)
 327                 return ret;
 328
 329         mutex_lock(&st->lock);
 330
 331         if (chan->type == IIO_TEMP)
 332                 st->temp_osr = osr;
 333         else
 334                 st->pressure_osr = osr;
 335
 336         mutex_unlock(&st->lock);
 337         iio_device_release_direct_mode(indio_dev);
 338
 339         return 0;
 340 }
 341
 342 static const unsigned long ms5611_scan_masks[] = {0x3, 0};
 343
 344 static const struct iio_chan_spec ms5611_channels[] = {
 345         {
 346                 .type = IIO_PRESSURE,
 347                 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
 348                         BIT(IIO_CHAN_INFO_SCALE) |
 349                         BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
 350                 .scan_index = 0,
 351                 .scan_type = {
 352                         .sign = 's',
 353                         .realbits = 32,
 354                         .storagebits = 32,
 355                         .endianness = IIO_CPU,
 356                 },
 357         },
 358         {
 359                 .type = IIO_TEMP,
 360                 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
 361                         BIT(IIO_CHAN_INFO_SCALE) |
 362                         BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
 363                 .scan_index = 1,
 364                 .scan_type = {
 365                         .sign = 's',
 366                         .realbits = 32,
 367                         .storagebits = 32,
 368                         .endianness = IIO_CPU,
 369                 },
 370         },
 371         IIO_CHAN_SOFT_TIMESTAMP(2),
 372 };
 373
 374 static const struct iio_info ms5611_info = {
 375         .read_raw = &ms5611_read_raw,
 376         .write_raw = &ms5611_write_raw,
 377         .attrs = &ms5611_attribute_group,
 378 };
 379
 380 static int ms5611_init(struct iio_dev *indio_dev)
 381 {
 382         int ret;
 383
 384         /* Enable attached regulator if any. */
 385         ret = devm_regulator_get_enable(indio_dev->dev.parent, "vdd");
 386         if (ret)
 387                 return ret;
 388
 389         ret = ms5611_reset(indio_dev);
 390         if (ret < 0)
 391                 return ret;
 392
 393         ret = ms5611_read_prom(indio_dev);
 394         if (ret < 0)
 395                 return ret;
 396
 397         return 0;
 398 }
 399
 400 int ms5611_probe(struct iio_dev *indio_dev, struct device *dev,
 401                  const char *name, int type)
 402 {
 403         int ret;
 404         struct ms5611_state *st = iio_priv(indio_dev);
 405
 406         mutex_init(&st->lock);
 407
 408         switch (type) {
 409         case MS5611:
 410                 st->compensate_temp_and_pressure =
 411                         ms5611_temp_and_pressure_compensate;
 412                 break;
 413         case MS5607:
 414                 st->compensate_temp_and_pressure =
 415                         ms5607_temp_and_pressure_compensate;
 416                 break;
 417         default:
 418                 return -EINVAL;
 419         }
 420
 421         st->temp_osr =
 422                 &ms5611_avail_temp_osr[ARRAY_SIZE(ms5611_avail_temp_osr) - 1];
 423         st->pressure_osr =
 424                 &ms5611_avail_pressure_osr[ARRAY_SIZE(ms5611_avail_pressure_osr)
 425                                            - 1];
 426         indio_dev->name = name;
 427         indio_dev->info = &ms5611_info;
 428         indio_dev->channels = ms5611_channels;
 429         indio_dev->num_channels = ARRAY_SIZE(ms5611_channels);
 430         indio_dev->modes = INDIO_DIRECT_MODE;
 431         indio_dev->available_scan_masks = ms5611_scan_masks;
 432
 433         ret = ms5611_init(indio_dev);
 434         if (ret < 0)
 435                 return ret;
 436
 437         ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL,
 438                                          ms5611_trigger_handler, NULL);
 439         if (ret < 0) {
 440                 dev_err(dev, "iio triggered buffer setup failed\n");
 441                 return ret;
 442         }
 443
 444         ret = devm_iio_device_register(dev, indio_dev);
 445         if (ret < 0) {
 446                 dev_err(dev, "unable to register iio device\n");
 447                 return ret;
 448         }
 449
 450         return 0;
 451 }
 452 EXPORT_SYMBOL_NS(ms5611_probe, "IIO_MS5611");
 453
 454 MODULE_AUTHOR("Tomasz Duszynski <tduszyns@gmail.com>");
 455 MODULE_DESCRIPTION("MS5611 core driver");
 456 MODULE_LICENSE("GPL v2");