drivers/iio/pressure/bmp280.c

   1 /*
   2  * Copyright (c) 2014 Intel Corporation
   3  *
   4  * Driver for Bosch Sensortec BMP180 and BMP280 digital pressure sensor.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  * Datasheet:
  11  * https://ae-bst.resource.bosch.com/media/_tech/media/datasheets/BST-BMP180-DS000-121.pdf
  12  * https://ae-bst.resource.bosch.com/media/_tech/media/datasheets/BST-BMP280-DS001-12.pdf
  13  */
  14
  15 #define pr_fmt(fmt) "bmp280: " fmt
  16
  17 #include <linux/module.h>
  18 #include <linux/i2c.h>
  19 #include <linux/acpi.h>
  20 #include <linux/regmap.h>
  21 #include <linux/delay.h>
  22 #include <linux/iio/iio.h>
  23 #include <linux/iio/sysfs.h>
  24
  25 /* BMP280 specific registers */
  26 #define BMP280_REG_TEMP_XLSB            0xFC
  27 #define BMP280_REG_TEMP_LSB             0xFB
  28 #define BMP280_REG_TEMP_MSB             0xFA
  29 #define BMP280_REG_PRESS_XLSB           0xF9
  30 #define BMP280_REG_PRESS_LSB            0xF8
  31 #define BMP280_REG_PRESS_MSB            0xF7
  32
  33 #define BMP280_REG_CONFIG               0xF5
  34 #define BMP280_REG_STATUS               0xF3
  35
  36 #define BMP280_REG_COMP_TEMP_START      0x88
  37 #define BMP280_COMP_TEMP_REG_COUNT      6
  38
  39 #define BMP280_REG_COMP_PRESS_START     0x8E
  40 #define BMP280_COMP_PRESS_REG_COUNT     18
  41
  42 #define BMP280_FILTER_MASK              (BIT(4) | BIT(3) | BIT(2))
  43 #define BMP280_FILTER_OFF               0
  44 #define BMP280_FILTER_2X                BIT(2)
  45 #define BMP280_FILTER_4X                BIT(3)
  46 #define BMP280_FILTER_8X                (BIT(3) | BIT(2))
  47 #define BMP280_FILTER_16X               BIT(4)
  48
  49 #define BMP280_OSRS_TEMP_MASK           (BIT(7) | BIT(6) | BIT(5))
  50 #define BMP280_OSRS_TEMP_SKIP           0
  51 #define BMP280_OSRS_TEMP_X(osrs_t)      ((osrs_t) << 5)
  52 #define BMP280_OSRS_TEMP_1X             BMP280_OSRS_TEMP_X(1)
  53 #define BMP280_OSRS_TEMP_2X             BMP280_OSRS_TEMP_X(2)
  54 #define BMP280_OSRS_TEMP_4X             BMP280_OSRS_TEMP_X(3)
  55 #define BMP280_OSRS_TEMP_8X             BMP280_OSRS_TEMP_X(4)
  56 #define BMP280_OSRS_TEMP_16X            BMP280_OSRS_TEMP_X(5)
  57
  58 #define BMP280_OSRS_PRESS_MASK          (BIT(4) | BIT(3) | BIT(2))
  59 #define BMP280_OSRS_PRESS_SKIP          0
  60 #define BMP280_OSRS_PRESS_X(osrs_p)     ((osrs_p) << 2)
  61 #define BMP280_OSRS_PRESS_1X            BMP280_OSRS_PRESS_X(1)
  62 #define BMP280_OSRS_PRESS_2X            BMP280_OSRS_PRESS_X(2)
  63 #define BMP280_OSRS_PRESS_4X            BMP280_OSRS_PRESS_X(3)
  64 #define BMP280_OSRS_PRESS_8X            BMP280_OSRS_PRESS_X(4)
  65 #define BMP280_OSRS_PRESS_16X           BMP280_OSRS_PRESS_X(5)
  66
  67 #define BMP280_MODE_MASK                (BIT(1) | BIT(0))
  68 #define BMP280_MODE_SLEEP               0
  69 #define BMP280_MODE_FORCED              BIT(0)
  70 #define BMP280_MODE_NORMAL              (BIT(1) | BIT(0))
  71
  72 /* BMP180 specific registers */
  73 #define BMP180_REG_OUT_XLSB             0xF8
  74 #define BMP180_REG_OUT_LSB              0xF7
  75 #define BMP180_REG_OUT_MSB              0xF6
  76
  77 #define BMP180_REG_CALIB_START          0xAA
  78 #define BMP180_REG_CALIB_COUNT          22
  79
  80 #define BMP180_MEAS_SCO                 BIT(5)
  81 #define BMP180_MEAS_TEMP                (0x0E | BMP180_MEAS_SCO)
  82 #define BMP180_MEAS_PRESS_X(oss)        ((oss) << 6 | 0x14 | BMP180_MEAS_SCO)
  83 #define BMP180_MEAS_PRESS_1X            BMP180_MEAS_PRESS_X(0)
  84 #define BMP180_MEAS_PRESS_2X            BMP180_MEAS_PRESS_X(1)
  85 #define BMP180_MEAS_PRESS_4X            BMP180_MEAS_PRESS_X(2)
  86 #define BMP180_MEAS_PRESS_8X            BMP180_MEAS_PRESS_X(3)
  87
  88 /* BMP180 and BMP280 common registers */
  89 #define BMP280_REG_CTRL_MEAS            0xF4
  90 #define BMP280_REG_RESET                0xE0
  91 #define BMP280_REG_ID                   0xD0
  92
  93 #define BMP180_CHIP_ID                  0x55
  94 #define BMP280_CHIP_ID                  0x58
  95 #define BMP280_SOFT_RESET_VAL           0xB6
  96
  97 struct bmp280_data {
  98         struct i2c_client *client;
  99         struct mutex lock;
 100         struct regmap *regmap;
 101         const struct bmp280_chip_info *chip_info;
 102
 103         /* log of base 2 of oversampling rate */
 104         u8 oversampling_press;
 105         u8 oversampling_temp;
 106
 107         /*
 108          * Carryover value from temperature conversion, used in pressure
 109          * calculation.
 110          */
 111         s32 t_fine;
 112 };
 113
 114 struct bmp280_chip_info {
 115         const struct regmap_config *regmap_config;
 116
 117         const int *oversampling_temp_avail;
 118         int num_oversampling_temp_avail;
 119
 120         const int *oversampling_press_avail;
 121         int num_oversampling_press_avail;
 122
 123         int (*chip_config)(struct bmp280_data *);
 124         int (*read_temp)(struct bmp280_data *, int *);
 125         int (*read_press)(struct bmp280_data *, int *, int *);
 126 };
 127
 128 /*
 129  * These enums are used for indexing into the array of compensation
 130  * parameters for BMP280.
 131  */
 132 enum { T1, T2, T3 };
 133 enum { P1, P2, P3, P4, P5, P6, P7, P8, P9 };
 134
 135 static const struct iio_chan_spec bmp280_channels[] = {
 136         {
 137                 .type = IIO_PRESSURE,
 138                 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
 139                                       BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
 140         },
 141         {
 142                 .type = IIO_TEMP,
 143                 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
 144                                       BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
 145         },
 146 };
 147
 148 static bool bmp280_is_writeable_reg(struct device *dev, unsigned int reg)
 149 {
 150         switch (reg) {
 151         case BMP280_REG_CONFIG:
 152         case BMP280_REG_CTRL_MEAS:
 153         case BMP280_REG_RESET:
 154                 return true;
 155         default:
 156                 return false;
 157         };
 158 }
 159
 160 static bool bmp280_is_volatile_reg(struct device *dev, unsigned int reg)
 161 {
 162         switch (reg) {
 163         case BMP280_REG_TEMP_XLSB:
 164         case BMP280_REG_TEMP_LSB:
 165         case BMP280_REG_TEMP_MSB:
 166         case BMP280_REG_PRESS_XLSB:
 167         case BMP280_REG_PRESS_LSB:
 168         case BMP280_REG_PRESS_MSB:
 169         case BMP280_REG_STATUS:
 170                 return true;
 171         default:
 172                 return false;
 173         }
 174 }
 175
 176 static const struct regmap_config bmp280_regmap_config = {
 177         .reg_bits = 8,
 178         .val_bits = 8,
 179
 180         .max_register = BMP280_REG_TEMP_XLSB,
 181         .cache_type = REGCACHE_RBTREE,
 182
 183         .writeable_reg = bmp280_is_writeable_reg,
 184         .volatile_reg = bmp280_is_volatile_reg,
 185 };
 186
 187 /*
 188  * Returns temperature in DegC, resolution is 0.01 DegC.  Output value of
 189  * "5123" equals 51.23 DegC.  t_fine carries fine temperature as global
 190  * value.
 191  *
 192  * Taken from datasheet, Section 3.11.3, "Compensation formula".
 193  */
 194 static s32 bmp280_compensate_temp(struct bmp280_data *data,
 195                                   s32 adc_temp)
 196 {
 197         int ret;
 198         s32 var1, var2;
 199         __le16 buf[BMP280_COMP_TEMP_REG_COUNT / 2];
 200
 201         ret = regmap_bulk_read(data->regmap, BMP280_REG_COMP_TEMP_START,
 202                                buf, BMP280_COMP_TEMP_REG_COUNT);
 203         if (ret < 0) {
 204                 dev_err(&data->client->dev,
 205                         "failed to read temperature calibration parameters\n");
 206                 return ret;
 207         }
 208
 209         /*
 210          * The double casts are necessary because le16_to_cpu returns an
 211          * unsigned 16-bit value.  Casting that value directly to a
 212          * signed 32-bit will not do proper sign extension.
 213          *
 214          * Conversely, T1 and P1 are unsigned values, so they can be
 215          * cast straight to the larger type.
 216          */
 217         var1 = (((adc_temp >> 3) - ((s32)le16_to_cpu(buf[T1]) << 1)) *
 218                 ((s32)(s16)le16_to_cpu(buf[T2]))) >> 11;
 219         var2 = (((((adc_temp >> 4) - ((s32)le16_to_cpu(buf[T1]))) *
 220                   ((adc_temp >> 4) - ((s32)le16_to_cpu(buf[T1])))) >> 12) *
 221                 ((s32)(s16)le16_to_cpu(buf[T3]))) >> 14;
 222         data->t_fine = var1 + var2;
 223
 224         return (data->t_fine * 5 + 128) >> 8;
 225 }
 226
 227 /*
 228  * Returns pressure in Pa as unsigned 32 bit integer in Q24.8 format (24
 229  * integer bits and 8 fractional bits).  Output value of "24674867"
 230  * represents 24674867/256 = 96386.2 Pa = 963.862 hPa
 231  *
 232  * Taken from datasheet, Section 3.11.3, "Compensation formula".
 233  */
 234 static u32 bmp280_compensate_press(struct bmp280_data *data,
 235                                    s32 adc_press)
 236 {
 237         int ret;
 238         s64 var1, var2, p;
 239         __le16 buf[BMP280_COMP_PRESS_REG_COUNT / 2];
 240
 241         ret = regmap_bulk_read(data->regmap, BMP280_REG_COMP_PRESS_START,
 242                                buf, BMP280_COMP_PRESS_REG_COUNT);
 243         if (ret < 0) {
 244                 dev_err(&data->client->dev,
 245                         "failed to read pressure calibration parameters\n");
 246                 return ret;
 247         }
 248
 249         var1 = ((s64)data->t_fine) - 128000;
 250         var2 = var1 * var1 * (s64)(s16)le16_to_cpu(buf[P6]);
 251         var2 += (var1 * (s64)(s16)le16_to_cpu(buf[P5])) << 17;
 252         var2 += ((s64)(s16)le16_to_cpu(buf[P4])) << 35;
 253         var1 = ((var1 * var1 * (s64)(s16)le16_to_cpu(buf[P3])) >> 8) +
 254                 ((var1 * (s64)(s16)le16_to_cpu(buf[P2])) << 12);
 255         var1 = ((((s64)1) << 47) + var1) * ((s64)le16_to_cpu(buf[P1])) >> 33;
 256
 257         if (var1 == 0)
 258                 return 0;
 259
 260         p = ((((s64)1048576 - adc_press) << 31) - var2) * 3125;
 261         p = div64_s64(p, var1);
 262         var1 = (((s64)(s16)le16_to_cpu(buf[P9])) * (p >> 13) * (p >> 13)) >> 25;
 263         var2 = (((s64)(s16)le16_to_cpu(buf[P8])) * p) >> 19;
 264         p = ((p + var1 + var2) >> 8) + (((s64)(s16)le16_to_cpu(buf[P7])) << 4);
 265
 266         return (u32)p;
 267 }
 268
 269 static int bmp280_read_temp(struct bmp280_data *data,
 270                             int *val)
 271 {
 272         int ret;
 273         __be32 tmp = 0;
 274         s32 adc_temp, comp_temp;
 275
 276         ret = regmap_bulk_read(data->regmap, BMP280_REG_TEMP_MSB,
 277                                (u8 *) &tmp, 3);
 278         if (ret < 0) {
 279                 dev_err(&data->client->dev, "failed to read temperature\n");
 280                 return ret;
 281         }
 282
 283         adc_temp = be32_to_cpu(tmp) >> 12;
 284         comp_temp = bmp280_compensate_temp(data, adc_temp);
 285
 286         /*
 287          * val might be NULL if we're called by the read_press routine,
 288          * who only cares about the carry over t_fine value.
 289          */
 290         if (val) {
 291                 *val = comp_temp * 10;
 292                 return IIO_VAL_INT;
 293         }
 294
 295         return 0;
 296 }
 297
 298 static int bmp280_read_press(struct bmp280_data *data,
 299                              int *val, int *val2)
 300 {
 301         int ret;
 302         __be32 tmp = 0;
 303         s32 adc_press;
 304         u32 comp_press;
 305
 306         /* Read and compensate temperature so we get a reading of t_fine. */
 307         ret = bmp280_read_temp(data, NULL);
 308         if (ret < 0)
 309                 return ret;
 310
 311         ret = regmap_bulk_read(data->regmap, BMP280_REG_PRESS_MSB,
 312                                (u8 *) &tmp, 3);
 313         if (ret < 0) {
 314                 dev_err(&data->client->dev, "failed to read pressure\n");
 315                 return ret;
 316         }
 317
 318         adc_press = be32_to_cpu(tmp) >> 12;
 319         comp_press = bmp280_compensate_press(data, adc_press);
 320
 321         *val = comp_press;
 322         *val2 = 256000;
 323
 324         return IIO_VAL_FRACTIONAL;
 325 }
 326
 327 static int bmp280_read_raw(struct iio_dev *indio_dev,
 328                            struct iio_chan_spec const *chan,
 329                            int *val, int *val2, long mask)
 330 {
 331         int ret;
 332         struct bmp280_data *data = iio_priv(indio_dev);
 333
 334         mutex_lock(&data->lock);
 335
 336         switch (mask) {
 337         case IIO_CHAN_INFO_PROCESSED:
 338                 switch (chan->type) {
 339                 case IIO_PRESSURE:
 340                         ret = data->chip_info->read_press(data, val, val2);
 341                         break;
 342                 case IIO_TEMP:
 343                         ret = data->chip_info->read_temp(data, val);
 344                         break;
 345                 default:
 346                         ret = -EINVAL;
 347                         break;
 348                 }
 349                 break;
 350         case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
 351                 switch (chan->type) {
 352                 case IIO_PRESSURE:
 353                         *val = 1 << data->oversampling_press;
 354                         ret = IIO_VAL_INT;
 355                         break;
 356                 case IIO_TEMP:
 357                         *val = 1 << data->oversampling_temp;
 358                         ret = IIO_VAL_INT;
 359                         break;
 360                 default:
 361                         ret = -EINVAL;
 362                         break;
 363                 }
 364                 break;
 365         default:
 366                 ret = -EINVAL;
 367                 break;
 368         }
 369
 370         mutex_unlock(&data->lock);
 371
 372         return ret;
 373 }
 374
 375 static int bmp280_write_oversampling_ratio_temp(struct bmp280_data *data,
 376                                                int val)
 377 {
 378         int i;
 379         const int *avail = data->chip_info->oversampling_temp_avail;
 380         const int n = data->chip_info->num_oversampling_temp_avail;
 381
 382         for (i = 0; i < n; i++) {
 383                 if (avail[i] == val) {
 384                         data->oversampling_temp = ilog2(val);
 385
 386                         return data->chip_info->chip_config(data);
 387                 }
 388         }
 389         return -EINVAL;
 390 }
 391
 392 static int bmp280_write_oversampling_ratio_press(struct bmp280_data *data,
 393                                                int val)
 394 {
 395         int i;
 396         const int *avail = data->chip_info->oversampling_press_avail;
 397         const int n = data->chip_info->num_oversampling_press_avail;
 398
 399         for (i = 0; i < n; i++) {
 400                 if (avail[i] == val) {
 401                         data->oversampling_press = ilog2(val);
 402
 403                         return data->chip_info->chip_config(data);
 404                 }
 405         }
 406         return -EINVAL;
 407 }
 408
 409 static int bmp280_write_raw(struct iio_dev *indio_dev,
 410                             struct iio_chan_spec const *chan,
 411                             int val, int val2, long mask)
 412 {
 413         int ret = 0;
 414         struct bmp280_data *data = iio_priv(indio_dev);
 415
 416         switch (mask) {
 417         case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
 418                 mutex_lock(&data->lock);
 419                 switch (chan->type) {
 420                 case IIO_PRESSURE:
 421                         ret = bmp280_write_oversampling_ratio_press(data, val);
 422                         break;
 423                 case IIO_TEMP:
 424                         ret = bmp280_write_oversampling_ratio_temp(data, val);
 425                         break;
 426                 default:
 427                         ret = -EINVAL;
 428                         break;
 429                 }
 430                 mutex_unlock(&data->lock);
 431                 break;
 432         default:
 433                 return -EINVAL;
 434         }
 435
 436         return ret;
 437 }
 438
 439 static ssize_t bmp280_show_avail(char *buf, const int *vals, const int n)
 440 {
 441         size_t len = 0;
 442         int i;
 443
 444         for (i = 0; i < n; i++)
 445                 len += scnprintf(buf + len, PAGE_SIZE - len, "%d ", vals[i]);
 446
 447         buf[len - 1] = '\n';
 448
 449         return len;
 450 }
 451
 452 static ssize_t bmp280_show_temp_oversampling_avail(struct device *dev,
 453                                 struct device_attribute *attr, char *buf)
 454 {
 455         struct bmp280_data *data = iio_priv(dev_to_iio_dev(dev));
 456
 457         return bmp280_show_avail(buf, data->chip_info->oversampling_temp_avail,
 458                                  data->chip_info->num_oversampling_temp_avail);
 459 }
 460
 461 static ssize_t bmp280_show_press_oversampling_avail(struct device *dev,
 462                                 struct device_attribute *attr, char *buf)
 463 {
 464         struct bmp280_data *data = iio_priv(dev_to_iio_dev(dev));
 465
 466         return bmp280_show_avail(buf, data->chip_info->oversampling_press_avail,
 467                                  data->chip_info->num_oversampling_press_avail);
 468 }
 469
 470 static IIO_DEVICE_ATTR(in_temp_oversampling_ratio_available,
 471         S_IRUGO, bmp280_show_temp_oversampling_avail, NULL, 0);
 472
 473 static IIO_DEVICE_ATTR(in_pressure_oversampling_ratio_available,
 474         S_IRUGO, bmp280_show_press_oversampling_avail, NULL, 0);
 475
 476 static struct attribute *bmp280_attributes[] = {
 477         &iio_dev_attr_in_temp_oversampling_ratio_available.dev_attr.attr,
 478         &iio_dev_attr_in_pressure_oversampling_ratio_available.dev_attr.attr,
 479         NULL,
 480 };
 481
 482 static const struct attribute_group bmp280_attrs_group = {
 483         .attrs = bmp280_attributes,
 484 };
 485
 486 static const struct iio_info bmp280_info = {
 487         .driver_module = THIS_MODULE,
 488         .read_raw = &bmp280_read_raw,
 489         .write_raw = &bmp280_write_raw,
 490         .attrs = &bmp280_attrs_group,
 491 };
 492
 493 static int bmp280_chip_config(struct bmp280_data *data)
 494 {
 495         int ret;
 496         u8 osrs = BMP280_OSRS_TEMP_X(data->oversampling_temp + 1) |
 497                   BMP280_OSRS_PRESS_X(data->oversampling_press + 1);
 498
 499         ret = regmap_update_bits(data->regmap, BMP280_REG_CTRL_MEAS,
 500                                  BMP280_OSRS_TEMP_MASK |
 501                                  BMP280_OSRS_PRESS_MASK |
 502                                  BMP280_MODE_MASK,
 503                                  osrs | BMP280_MODE_NORMAL);
 504         if (ret < 0) {
 505                 dev_err(&data->client->dev,
 506                         "failed to write ctrl_meas register\n");
 507                 return ret;
 508         }
 509
 510         ret = regmap_update_bits(data->regmap, BMP280_REG_CONFIG,
 511                                  BMP280_FILTER_MASK,
 512                                  BMP280_FILTER_4X);
 513         if (ret < 0) {
 514                 dev_err(&data->client->dev,
 515                         "failed to write config register\n");
 516                 return ret;
 517         }
 518
 519         return ret;
 520 }
 521
 522 static const int bmp280_oversampling_avail[] = { 1, 2, 4, 8, 16 };
 523
 524 static const struct bmp280_chip_info bmp280_chip_info = {
 525         .regmap_config = &bmp280_regmap_config,
 526
 527         .oversampling_temp_avail = bmp280_oversampling_avail,
 528         .num_oversampling_temp_avail = ARRAY_SIZE(bmp280_oversampling_avail),
 529
 530         .oversampling_press_avail = bmp280_oversampling_avail,
 531         .num_oversampling_press_avail = ARRAY_SIZE(bmp280_oversampling_avail),
 532
 533         .chip_config = bmp280_chip_config,
 534         .read_temp = bmp280_read_temp,
 535         .read_press = bmp280_read_press,
 536 };
 537
 538 static bool bmp180_is_writeable_reg(struct device *dev, unsigned int reg)
 539 {
 540         switch (reg) {
 541         case BMP280_REG_CTRL_MEAS:
 542         case BMP280_REG_RESET:
 543                 return true;
 544         default:
 545                 return false;
 546         };
 547 }
 548
 549 static bool bmp180_is_volatile_reg(struct device *dev, unsigned int reg)
 550 {
 551         switch (reg) {
 552         case BMP180_REG_OUT_XLSB:
 553         case BMP180_REG_OUT_LSB:
 554         case BMP180_REG_OUT_MSB:
 555         case BMP280_REG_CTRL_MEAS:
 556                 return true;
 557         default:
 558                 return false;
 559         }
 560 }
 561
 562 static const struct regmap_config bmp180_regmap_config = {
 563         .reg_bits = 8,
 564         .val_bits = 8,
 565
 566         .max_register = BMP180_REG_OUT_XLSB,
 567         .cache_type = REGCACHE_RBTREE,
 568
 569         .writeable_reg = bmp180_is_writeable_reg,
 570         .volatile_reg = bmp180_is_volatile_reg,
 571 };
 572
 573 static int bmp180_measure(struct bmp280_data *data, u8 ctrl_meas)
 574 {
 575         int ret;
 576         const int conversion_time_max[] = { 4500, 7500, 13500, 25500 };
 577         unsigned int delay_us;
 578         unsigned int ctrl;
 579
 580         ret = regmap_write(data->regmap, BMP280_REG_CTRL_MEAS, ctrl_meas);
 581         if (ret)
 582                 return ret;
 583
 584         if (ctrl_meas == BMP180_MEAS_TEMP)
 585                 delay_us = 4500;
 586         else
 587                 delay_us = conversion_time_max[data->oversampling_press];
 588
 589         usleep_range(delay_us, delay_us + 1000);
 590
 591         ret = regmap_read(data->regmap, BMP280_REG_CTRL_MEAS, &ctrl);
 592         if (ret)
 593                 return ret;
 594
 595         /* The value of this bit reset to "0" after conversion is complete */
 596         if (ctrl & BMP180_MEAS_SCO)
 597                 return -EIO;
 598
 599         return 0;
 600 }
 601
 602 static int bmp180_read_adc_temp(struct bmp280_data *data, int *val)
 603 {
 604         int ret;
 605         __be16 tmp = 0;
 606
 607         ret = bmp180_measure(data, BMP180_MEAS_TEMP);
 608         if (ret)
 609                 return ret;
 610
 611         ret = regmap_bulk_read(data->regmap, BMP180_REG_OUT_MSB, (u8 *)&tmp, 2);
 612         if (ret)
 613                 return ret;
 614
 615         *val = be16_to_cpu(tmp);
 616
 617         return 0;
 618 }
 619
 620 /*
 621  * These enums are used for indexing into the array of calibration
 622  * coefficients for BMP180.
 623  */
 624 enum { AC1, AC2, AC3, AC4, AC5, AC6, B1, B2, MB, MC, MD };
 625
 626 struct bmp180_calib {
 627         s16 AC1;
 628         s16 AC2;
 629         s16 AC3;
 630         u16 AC4;
 631         u16 AC5;
 632         u16 AC6;
 633         s16 B1;
 634         s16 B2;
 635         s16 MB;
 636         s16 MC;
 637         s16 MD;
 638 };
 639
 640 static int bmp180_read_calib(struct bmp280_data *data,
 641                              struct bmp180_calib *calib)
 642 {
 643         int ret;
 644         int i;
 645         __be16 buf[BMP180_REG_CALIB_COUNT / 2];
 646
 647         ret = regmap_bulk_read(data->regmap, BMP180_REG_CALIB_START, buf,
 648                                sizeof(buf));
 649
 650         if (ret < 0)
 651                 return ret;
 652
 653         /* None of the words has the value 0 or 0xFFFF */
 654         for (i = 0; i < ARRAY_SIZE(buf); i++) {
 655                 if (buf[i] == cpu_to_be16(0) || buf[i] == cpu_to_be16(0xffff))
 656                         return -EIO;
 657         }
 658
 659         calib->AC1 = be16_to_cpu(buf[AC1]);
 660         calib->AC2 = be16_to_cpu(buf[AC2]);
 661         calib->AC3 = be16_to_cpu(buf[AC3]);
 662         calib->AC4 = be16_to_cpu(buf[AC4]);
 663         calib->AC5 = be16_to_cpu(buf[AC5]);
 664         calib->AC6 = be16_to_cpu(buf[AC6]);
 665         calib->B1 = be16_to_cpu(buf[B1]);
 666         calib->B2 = be16_to_cpu(buf[B2]);
 667         calib->MB = be16_to_cpu(buf[MB]);
 668         calib->MC = be16_to_cpu(buf[MC]);
 669         calib->MD = be16_to_cpu(buf[MD]);
 670
 671         return 0;
 672 }
 673
 674 /*
 675  * Returns temperature in DegC, resolution is 0.1 DegC.
 676  * t_fine carries fine temperature as global value.
 677  *
 678  * Taken from datasheet, Section 3.5, "Calculating pressure and temperature".
 679  */
 680 static s32 bmp180_compensate_temp(struct bmp280_data *data, s32 adc_temp)
 681 {
 682         int ret;
 683         s32 x1, x2;
 684         struct bmp180_calib calib;
 685
 686         ret = bmp180_read_calib(data, &calib);
 687         if (ret < 0) {
 688                 dev_err(&data->client->dev,
 689                         "failed to read calibration coefficients\n");
 690                 return ret;
 691         }
 692
 693         x1 = ((adc_temp - calib.AC6) * calib.AC5) >> 15;
 694         x2 = (calib.MC << 11) / (x1 + calib.MD);
 695         data->t_fine = x1 + x2;
 696
 697         return (data->t_fine + 8) >> 4;
 698 }
 699
 700 static int bmp180_read_temp(struct bmp280_data *data, int *val)
 701 {
 702         int ret;
 703         s32 adc_temp, comp_temp;
 704
 705         ret = bmp180_read_adc_temp(data, &adc_temp);
 706         if (ret)
 707                 return ret;
 708
 709         comp_temp = bmp180_compensate_temp(data, adc_temp);
 710
 711         /*
 712          * val might be NULL if we're called by the read_press routine,
 713          * who only cares about the carry over t_fine value.
 714          */
 715         if (val) {
 716                 *val = comp_temp * 100;
 717                 return IIO_VAL_INT;
 718         }
 719
 720         return 0;
 721 }
 722
 723 static int bmp180_read_adc_press(struct bmp280_data *data, int *val)
 724 {
 725         int ret;
 726         __be32 tmp = 0;
 727         u8 oss = data->oversampling_press;
 728
 729         ret = bmp180_measure(data, BMP180_MEAS_PRESS_X(oss));
 730         if (ret)
 731                 return ret;
 732
 733         ret = regmap_bulk_read(data->regmap, BMP180_REG_OUT_MSB, (u8 *)&tmp, 3);
 734         if (ret)
 735                 return ret;
 736
 737         *val = (be32_to_cpu(tmp) >> 8) >> (8 - oss);
 738
 739         return 0;
 740 }
 741
 742 /*
 743  * Returns pressure in Pa, resolution is 1 Pa.
 744  *
 745  * Taken from datasheet, Section 3.5, "Calculating pressure and temperature".
 746  */
 747 static u32 bmp180_compensate_press(struct bmp280_data *data, s32 adc_press)
 748 {
 749         int ret;
 750         s32 x1, x2, x3, p;
 751         s32 b3, b6;
 752         u32 b4, b7;
 753         s32 oss = data->oversampling_press;
 754         struct bmp180_calib calib;
 755
 756         ret = bmp180_read_calib(data, &calib);
 757         if (ret < 0) {
 758                 dev_err(&data->client->dev,
 759                         "failed to read calibration coefficients\n");
 760                 return ret;
 761         }
 762
 763         b6 = data->t_fine - 4000;
 764         x1 = (calib.B2 * (b6 * b6 >> 12)) >> 11;
 765         x2 = calib.AC2 * b6 >> 11;
 766         x3 = x1 + x2;
 767         b3 = ((((s32)calib.AC1 * 4 + x3) << oss) + 2) / 4;
 768         x1 = calib.AC3 * b6 >> 13;
 769         x2 = (calib.B1 * ((b6 * b6) >> 12)) >> 16;
 770         x3 = (x1 + x2 + 2) >> 2;
 771         b4 = calib.AC4 * (u32)(x3 + 32768) >> 15;
 772         b7 = ((u32)adc_press - b3) * (50000 >> oss);
 773         if (b7 < 0x80000000)
 774                 p = (b7 * 2) / b4;
 775         else
 776                 p = (b7 / b4) * 2;
 777
 778         x1 = (p >> 8) * (p >> 8);
 779         x1 = (x1 * 3038) >> 16;
 780         x2 = (-7357 * p) >> 16;
 781
 782         return p + ((x1 + x2 + 3791) >> 4);
 783 }
 784
 785 static int bmp180_read_press(struct bmp280_data *data,
 786                              int *val, int *val2)
 787 {
 788         int ret;
 789         s32 adc_press;
 790         u32 comp_press;
 791
 792         /* Read and compensate temperature so we get a reading of t_fine. */
 793         ret = bmp180_read_temp(data, NULL);
 794         if (ret)
 795                 return ret;
 796
 797         ret = bmp180_read_adc_press(data, &adc_press);
 798         if (ret)
 799                 return ret;
 800
 801         comp_press = bmp180_compensate_press(data, adc_press);
 802
 803         *val = comp_press;
 804         *val2 = 1000;
 805
 806         return IIO_VAL_FRACTIONAL;
 807 }
 808
 809 static int bmp180_chip_config(struct bmp280_data *data)
 810 {
 811         return 0;
 812 }
 813
 814 static const int bmp180_oversampling_temp_avail[] = { 1 };
 815 static const int bmp180_oversampling_press_avail[] = { 1, 2, 4, 8 };
 816
 817 static const struct bmp280_chip_info bmp180_chip_info = {
 818         .regmap_config = &bmp180_regmap_config,
 819
 820         .oversampling_temp_avail = bmp180_oversampling_temp_avail,
 821         .num_oversampling_temp_avail =
 822                 ARRAY_SIZE(bmp180_oversampling_temp_avail),
 823
 824         .oversampling_press_avail = bmp180_oversampling_press_avail,
 825         .num_oversampling_press_avail =
 826                 ARRAY_SIZE(bmp180_oversampling_press_avail),
 827
 828         .chip_config = bmp180_chip_config,
 829         .read_temp = bmp180_read_temp,
 830         .read_press = bmp180_read_press,
 831 };
 832
 833 static int bmp280_probe(struct i2c_client *client,
 834                         const struct i2c_device_id *id)
 835 {
 836         int ret;
 837         struct iio_dev *indio_dev;
 838         struct bmp280_data *data;
 839         unsigned int chip_id;
 840
 841         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 842         if (!indio_dev)
 843                 return -ENOMEM;
 844
 845         data = iio_priv(indio_dev);
 846         mutex_init(&data->lock);
 847         data->client = client;
 848
 849         indio_dev->dev.parent = &client->dev;
 850         indio_dev->name = id->name;
 851         indio_dev->channels = bmp280_channels;
 852         indio_dev->num_channels = ARRAY_SIZE(bmp280_channels);
 853         indio_dev->info = &bmp280_info;
 854         indio_dev->modes = INDIO_DIRECT_MODE;
 855
 856         switch (id->driver_data) {
 857         case BMP180_CHIP_ID:
 858                 data->chip_info = &bmp180_chip_info;
 859                 data->oversampling_press = ilog2(8);
 860                 data->oversampling_temp = ilog2(1);
 861                 break;
 862         case BMP280_CHIP_ID:
 863                 data->chip_info = &bmp280_chip_info;
 864                 data->oversampling_press = ilog2(16);
 865                 data->oversampling_temp = ilog2(2);
 866                 break;
 867         default:
 868                 return -EINVAL;
 869         }
 870
 871         data->regmap = devm_regmap_init_i2c(client,
 872                                         data->chip_info->regmap_config);
 873         if (IS_ERR(data->regmap)) {
 874                 dev_err(&client->dev, "failed to allocate register map\n");
 875                 return PTR_ERR(data->regmap);
 876         }
 877
 878         ret = regmap_read(data->regmap, BMP280_REG_ID, &chip_id);
 879         if (ret < 0)
 880                 return ret;
 881         if (chip_id != id->driver_data) {
 882                 dev_err(&client->dev, "bad chip id.  expected %x got %x\n",
 883                         BMP280_CHIP_ID, chip_id);
 884                 return -EINVAL;
 885         }
 886
 887         ret = data->chip_info->chip_config(data);
 888         if (ret < 0)
 889                 return ret;
 890
 891         return devm_iio_device_register(&client->dev, indio_dev);
 892 }
 893
 894 static const struct acpi_device_id bmp280_acpi_match[] = {
 895         {"BMP0280", BMP280_CHIP_ID },
 896         {"BMP0180", BMP180_CHIP_ID },
 897         {"BMP0085", BMP180_CHIP_ID },
 898         { },
 899 };
 900 MODULE_DEVICE_TABLE(acpi, bmp280_acpi_match);
 901
 902 static const struct i2c_device_id bmp280_id[] = {
 903         {"bmp280", BMP280_CHIP_ID },
 904         {"bmp180", BMP180_CHIP_ID },
 905         {"bmp085", BMP180_CHIP_ID },
 906         { },
 907 };
 908 MODULE_DEVICE_TABLE(i2c, bmp280_id);
 909
 910 static struct i2c_driver bmp280_driver = {
 911         .driver = {
 912                 .name   = "bmp280",
 913                 .acpi_match_table = ACPI_PTR(bmp280_acpi_match),
 914         },
 915         .probe          = bmp280_probe,
 916         .id_table       = bmp280_id,
 917 };
 918 module_i2c_driver(bmp280_driver);
 919
 920 MODULE_AUTHOR("Vlad Dogaru <vlad.dogaru@intel.com>");
 921 MODULE_DESCRIPTION("Driver for Bosch Sensortec BMP180/BMP280 pressure and temperature sensor");
 922 MODULE_LICENSE("GPL v2");