drivers/iio/magnetometer/mmc35240.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * MMC35240 - MEMSIC 3-axis Magnetic Sensor
   4  *
   5  * Copyright (c) 2015, Intel Corporation.
   6  *
   7  * IIO driver for MMC35240 (7-bit I2C slave address 0x30).
   8  *
   9  * TODO: offset, ACPI, continuous measurement mode, PM
  10  */
  11
  12 #include <linux/module.h>
  13 #include <linux/mod_devicetable.h>
  14 #include <linux/init.h>
  15 #include <linux/i2c.h>
  16 #include <linux/delay.h>
  17 #include <linux/regmap.h>
  18 #include <linux/pm.h>
  19
  20 #include <linux/iio/iio.h>
  21 #include <linux/iio/sysfs.h>
  22
  23 #define MMC35240_DRV_NAME "mmc35240"
  24 #define MMC35240_REGMAP_NAME "mmc35240_regmap"
  25
  26 #define MMC35240_REG_XOUT_L     0x00
  27 #define MMC35240_REG_XOUT_H     0x01
  28 #define MMC35240_REG_YOUT_L     0x02
  29 #define MMC35240_REG_YOUT_H     0x03
  30 #define MMC35240_REG_ZOUT_L     0x04
  31 #define MMC35240_REG_ZOUT_H     0x05
  32
  33 #define MMC35240_REG_STATUS     0x06
  34 #define MMC35240_REG_CTRL0      0x07
  35 #define MMC35240_REG_CTRL1      0x08
  36
  37 #define MMC35240_REG_ID         0x20
  38
  39 #define MMC35240_STATUS_MEAS_DONE_BIT   BIT(0)
  40
  41 #define MMC35240_CTRL0_REFILL_BIT       BIT(7)
  42 #define MMC35240_CTRL0_RESET_BIT        BIT(6)
  43 #define MMC35240_CTRL0_SET_BIT          BIT(5)
  44 #define MMC35240_CTRL0_CMM_BIT          BIT(1)
  45 #define MMC35240_CTRL0_TM_BIT           BIT(0)
  46
  47 /* output resolution bits */
  48 #define MMC35240_CTRL1_BW0_BIT          BIT(0)
  49 #define MMC35240_CTRL1_BW1_BIT          BIT(1)
  50
  51 #define MMC35240_CTRL1_BW_MASK   (MMC35240_CTRL1_BW0_BIT | \
  52                  MMC35240_CTRL1_BW1_BIT)
  53 #define MMC35240_CTRL1_BW_SHIFT         0
  54
  55 #define MMC35240_WAIT_CHARGE_PUMP       50000   /* us */
  56 #define MMC35240_WAIT_SET_RESET         1000    /* us */
  57
  58 /*
  59  * Memsic OTP process code piece is put here for reference:
  60  *
  61  * #define OTP_CONVERT(REG)  ((float)((REG) >=32 ? (32 - (REG)) : (REG)) * 0.006
  62  * 1) For X axis, the COEFFICIENT is always 1.
  63  * 2) For Y axis, the COEFFICIENT is as below:
  64  *    f_OTP_matrix[4] = OTP_CONVERT(((reg_data[1] & 0x03) << 4) |
  65  *                                   (reg_data[2] >> 4)) + 1.0;
  66  * 3) For Z axis, the COEFFICIENT is as below:
  67  *    f_OTP_matrix[8] = (OTP_CONVERT(reg_data[3] & 0x3f) + 1) * 1.35;
  68  * We implemented the OTP logic into driver.
  69  */
  70
  71 /* scale = 1000 here for Y otp */
  72 #define MMC35240_OTP_CONVERT_Y(REG) (((REG) >= 32 ? (32 - (REG)) : (REG)) * 6)
  73
  74 /* 0.6 * 1.35 = 0.81, scale 10000 for Z otp */
  75 #define MMC35240_OTP_CONVERT_Z(REG) (((REG) >= 32 ? (32 - (REG)) : (REG)) * 81)
  76
  77 #define MMC35240_X_COEFF(x)     (x)
  78 #define MMC35240_Y_COEFF(y)     (y + 1000)
  79 #define MMC35240_Z_COEFF(z)     (z + 13500)
  80
  81 #define MMC35240_OTP_START_ADDR         0x1B
  82
  83 enum mmc35240_resolution {
  84         MMC35240_16_BITS_SLOW = 0, /* 7.92 ms */
  85         MMC35240_16_BITS_FAST,     /* 4.08 ms */
  86         MMC35240_14_BITS,          /* 2.16 ms */
  87         MMC35240_12_BITS,          /* 1.20 ms */
  88 };
  89
  90 enum mmc35240_axis {
  91         AXIS_X = 0,
  92         AXIS_Y,
  93         AXIS_Z,
  94 };
  95
  96 static const struct {
  97         int sens[3]; /* sensitivity per X, Y, Z axis */
  98         int nfo; /* null field output */
  99 } mmc35240_props_table[] = {
 100         /* 16 bits, 125Hz ODR */
 101         {
 102                 {1024, 1024, 1024},
 103                 32768,
 104         },
 105         /* 16 bits, 250Hz ODR */
 106         {
 107                 {1024, 1024, 770},
 108                 32768,
 109         },
 110         /* 14 bits, 450Hz ODR */
 111         {
 112                 {256, 256, 193},
 113                 8192,
 114         },
 115         /* 12 bits, 800Hz ODR */
 116         {
 117                 {64, 64, 48},
 118                 2048,
 119         },
 120 };
 121
 122 struct mmc35240_data {
 123         struct i2c_client *client;
 124         struct mutex mutex;
 125         struct regmap *regmap;
 126         enum mmc35240_resolution res;
 127
 128         /* OTP compensation */
 129         int axis_coef[3];
 130         int axis_scale[3];
 131 };
 132
 133 static const struct {
 134         int val;
 135         int val2;
 136 } mmc35240_samp_freq[] = { {1, 500000},
 137                            {13, 0},
 138                            {25, 0},
 139                            {50, 0} };
 140
 141 static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("1.5 13 25 50");
 142
 143 #define MMC35240_CHANNEL(_axis) { \
 144         .type = IIO_MAGN, \
 145         .modified = 1, \
 146         .channel2 = IIO_MOD_ ## _axis, \
 147         .address = AXIS_ ## _axis, \
 148         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
 149         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ) | \
 150                         BIT(IIO_CHAN_INFO_SCALE), \
 151 }
 152
 153 static const struct iio_chan_spec mmc35240_channels[] = {
 154         MMC35240_CHANNEL(X),
 155         MMC35240_CHANNEL(Y),
 156         MMC35240_CHANNEL(Z),
 157 };
 158
 159 static struct attribute *mmc35240_attributes[] = {
 160         &iio_const_attr_sampling_frequency_available.dev_attr.attr,
 161         NULL
 162 };
 163
 164 static const struct attribute_group mmc35240_attribute_group = {
 165         .attrs = mmc35240_attributes,
 166 };
 167
 168 static int mmc35240_get_samp_freq_index(struct mmc35240_data *data,
 169                                         int val, int val2)
 170 {
 171         int i;
 172
 173         for (i = 0; i < ARRAY_SIZE(mmc35240_samp_freq); i++)
 174                 if (mmc35240_samp_freq[i].val == val &&
 175                     mmc35240_samp_freq[i].val2 == val2)
 176                         return i;
 177         return -EINVAL;
 178 }
 179
 180 static int mmc35240_hw_set(struct mmc35240_data *data, bool set)
 181 {
 182         int ret;
 183         u8 coil_bit;
 184
 185         /*
 186          * Recharge the capacitor at VCAP pin, requested to be issued
 187          * before a SET/RESET command.
 188          */
 189         ret = regmap_set_bits(data->regmap, MMC35240_REG_CTRL0,
 190                               MMC35240_CTRL0_REFILL_BIT);
 191         if (ret < 0)
 192                 return ret;
 193         usleep_range(MMC35240_WAIT_CHARGE_PUMP, MMC35240_WAIT_CHARGE_PUMP + 1);
 194
 195         if (set)
 196                 coil_bit = MMC35240_CTRL0_SET_BIT;
 197         else
 198                 coil_bit = MMC35240_CTRL0_RESET_BIT;
 199
 200         return regmap_set_bits(data->regmap, MMC35240_REG_CTRL0, coil_bit);
 201
 202 }
 203
 204 static int mmc35240_init(struct mmc35240_data *data)
 205 {
 206         int ret, y_convert, z_convert;
 207         unsigned int reg_id;
 208         u8 otp_data[6];
 209
 210         ret = regmap_read(data->regmap, MMC35240_REG_ID, &reg_id);
 211         if (ret < 0) {
 212                 dev_err(&data->client->dev, "Error reading product id\n");
 213                 return ret;
 214         }
 215
 216         dev_dbg(&data->client->dev, "MMC35240 chip id %x\n", reg_id);
 217
 218         /*
 219          * make sure we restore sensor characteristics, by doing
 220          * a SET/RESET sequence, the axis polarity being naturally
 221          * aligned after RESET
 222          */
 223         ret = mmc35240_hw_set(data, true);
 224         if (ret < 0)
 225                 return ret;
 226         usleep_range(MMC35240_WAIT_SET_RESET, MMC35240_WAIT_SET_RESET + 1);
 227
 228         ret = mmc35240_hw_set(data, false);
 229         if (ret < 0)
 230                 return ret;
 231
 232         /* set default sampling frequency */
 233         ret = regmap_update_bits(data->regmap, MMC35240_REG_CTRL1,
 234                                  MMC35240_CTRL1_BW_MASK,
 235                                  data->res << MMC35240_CTRL1_BW_SHIFT);
 236         if (ret < 0)
 237                 return ret;
 238
 239         ret = regmap_bulk_read(data->regmap, MMC35240_OTP_START_ADDR,
 240                                otp_data, sizeof(otp_data));
 241         if (ret < 0)
 242                 return ret;
 243
 244         y_convert = MMC35240_OTP_CONVERT_Y(((otp_data[1] & 0x03) << 4) |
 245                                            (otp_data[2] >> 4));
 246         z_convert = MMC35240_OTP_CONVERT_Z(otp_data[3] & 0x3f);
 247
 248         data->axis_coef[0] = MMC35240_X_COEFF(1);
 249         data->axis_coef[1] = MMC35240_Y_COEFF(y_convert);
 250         data->axis_coef[2] = MMC35240_Z_COEFF(z_convert);
 251
 252         data->axis_scale[0] = 1;
 253         data->axis_scale[1] = 1000;
 254         data->axis_scale[2] = 10000;
 255
 256         return 0;
 257 }
 258
 259 static int mmc35240_take_measurement(struct mmc35240_data *data)
 260 {
 261         int ret, tries = 100;
 262         unsigned int reg_status;
 263
 264         ret = regmap_write(data->regmap, MMC35240_REG_CTRL0,
 265                            MMC35240_CTRL0_TM_BIT);
 266         if (ret < 0)
 267                 return ret;
 268
 269         while (tries-- > 0) {
 270                 ret = regmap_read(data->regmap, MMC35240_REG_STATUS,
 271                                   &reg_status);
 272                 if (ret < 0)
 273                         return ret;
 274                 if (reg_status & MMC35240_STATUS_MEAS_DONE_BIT)
 275                         break;
 276                 /* minimum wait time to complete measurement is 10 ms */
 277                 usleep_range(10000, 11000);
 278         }
 279
 280         if (tries < 0) {
 281                 dev_err(&data->client->dev, "data not ready\n");
 282                 return -EIO;
 283         }
 284
 285         return 0;
 286 }
 287
 288 static int mmc35240_read_measurement(struct mmc35240_data *data, __le16 buf[3])
 289 {
 290         int ret;
 291
 292         ret = mmc35240_take_measurement(data);
 293         if (ret < 0)
 294                 return ret;
 295
 296         return regmap_bulk_read(data->regmap, MMC35240_REG_XOUT_L, buf,
 297                                 3 * sizeof(__le16));
 298 }
 299
 300 /**
 301  * mmc35240_raw_to_mgauss - convert raw readings to milli gauss. Also apply
 302  *                          compensation for output value.
 303  *
 304  * @data: device private data
 305  * @index: axis index for which we want the conversion
 306  * @buf: raw data to be converted, 2 bytes in little endian format
 307  * @val: compensated output reading (unit is milli gauss)
 308  *
 309  * Returns: 0 in case of success, -EINVAL when @index is not valid
 310  */
 311 static int mmc35240_raw_to_mgauss(struct mmc35240_data *data, int index,
 312                                   __le16 buf[], int *val)
 313 {
 314         int raw[3];
 315         int sens[3];
 316         int nfo;
 317
 318         raw[AXIS_X] = le16_to_cpu(buf[AXIS_X]);
 319         raw[AXIS_Y] = le16_to_cpu(buf[AXIS_Y]);
 320         raw[AXIS_Z] = le16_to_cpu(buf[AXIS_Z]);
 321
 322         sens[AXIS_X] = mmc35240_props_table[data->res].sens[AXIS_X];
 323         sens[AXIS_Y] = mmc35240_props_table[data->res].sens[AXIS_Y];
 324         sens[AXIS_Z] = mmc35240_props_table[data->res].sens[AXIS_Z];
 325
 326         nfo = mmc35240_props_table[data->res].nfo;
 327
 328         switch (index) {
 329         case AXIS_X:
 330                 *val = (raw[AXIS_X] - nfo) * 1000 / sens[AXIS_X];
 331                 break;
 332         case AXIS_Y:
 333                 *val = (raw[AXIS_Y] - nfo) * 1000 / sens[AXIS_Y] -
 334                         (raw[AXIS_Z] - nfo)  * 1000 / sens[AXIS_Z];
 335                 break;
 336         case AXIS_Z:
 337                 *val = (raw[AXIS_Y] - nfo) * 1000 / sens[AXIS_Y] +
 338                         (raw[AXIS_Z] - nfo) * 1000 / sens[AXIS_Z];
 339                 break;
 340         default:
 341                 return -EINVAL;
 342         }
 343         /* apply OTP compensation */
 344         *val = (*val) * data->axis_coef[index] / data->axis_scale[index];
 345
 346         return 0;
 347 }
 348
 349 static int mmc35240_read_raw(struct iio_dev *indio_dev,
 350                              struct iio_chan_spec const *chan, int *val,
 351                              int *val2, long mask)
 352 {
 353         struct mmc35240_data *data = iio_priv(indio_dev);
 354         int ret, i;
 355         unsigned int reg;
 356         __le16 buf[3];
 357
 358         switch (mask) {
 359         case IIO_CHAN_INFO_RAW:
 360                 mutex_lock(&data->mutex);
 361                 ret = mmc35240_read_measurement(data, buf);
 362                 mutex_unlock(&data->mutex);
 363                 if (ret < 0)
 364                         return ret;
 365                 ret = mmc35240_raw_to_mgauss(data, chan->address, buf, val);
 366                 if (ret < 0)
 367                         return ret;
 368                 return IIO_VAL_INT;
 369         case IIO_CHAN_INFO_SCALE:
 370                 *val = 0;
 371                 *val2 = 1000;
 372                 return IIO_VAL_INT_PLUS_MICRO;
 373         case IIO_CHAN_INFO_SAMP_FREQ:
 374                 mutex_lock(&data->mutex);
 375                 ret = regmap_read(data->regmap, MMC35240_REG_CTRL1, &reg);
 376                 mutex_unlock(&data->mutex);
 377                 if (ret < 0)
 378                         return ret;
 379
 380                 i = (reg & MMC35240_CTRL1_BW_MASK) >> MMC35240_CTRL1_BW_SHIFT;
 381                 if (i < 0 || i >= ARRAY_SIZE(mmc35240_samp_freq))
 382                         return -EINVAL;
 383
 384                 *val = mmc35240_samp_freq[i].val;
 385                 *val2 = mmc35240_samp_freq[i].val2;
 386                 return IIO_VAL_INT_PLUS_MICRO;
 387         default:
 388                 return -EINVAL;
 389         }
 390 }
 391
 392 static int mmc35240_write_raw(struct iio_dev *indio_dev,
 393                               struct iio_chan_spec const *chan, int val,
 394                               int val2, long mask)
 395 {
 396         struct mmc35240_data *data = iio_priv(indio_dev);
 397         int i, ret;
 398
 399         switch (mask) {
 400         case IIO_CHAN_INFO_SAMP_FREQ:
 401                 i = mmc35240_get_samp_freq_index(data, val, val2);
 402                 if (i < 0)
 403                         return -EINVAL;
 404                 mutex_lock(&data->mutex);
 405                 ret = regmap_update_bits(data->regmap, MMC35240_REG_CTRL1,
 406                                          MMC35240_CTRL1_BW_MASK,
 407                                          i << MMC35240_CTRL1_BW_SHIFT);
 408                 mutex_unlock(&data->mutex);
 409                 return ret;
 410         default:
 411                 return -EINVAL;
 412         }
 413 }
 414
 415 static const struct iio_info mmc35240_info = {
 416         .read_raw       = mmc35240_read_raw,
 417         .write_raw      = mmc35240_write_raw,
 418         .attrs          = &mmc35240_attribute_group,
 419 };
 420
 421 static bool mmc35240_is_writeable_reg(struct device *dev, unsigned int reg)
 422 {
 423         switch (reg) {
 424         case MMC35240_REG_CTRL0:
 425         case MMC35240_REG_CTRL1:
 426                 return true;
 427         default:
 428                 return false;
 429         }
 430 }
 431
 432 static bool mmc35240_is_readable_reg(struct device *dev, unsigned int reg)
 433 {
 434         switch (reg) {
 435         case MMC35240_REG_XOUT_L:
 436         case MMC35240_REG_XOUT_H:
 437         case MMC35240_REG_YOUT_L:
 438         case MMC35240_REG_YOUT_H:
 439         case MMC35240_REG_ZOUT_L:
 440         case MMC35240_REG_ZOUT_H:
 441         case MMC35240_REG_STATUS:
 442         case MMC35240_REG_ID:
 443                 return true;
 444         default:
 445                 return false;
 446         }
 447 }
 448
 449 static bool mmc35240_is_volatile_reg(struct device *dev, unsigned int reg)
 450 {
 451         switch (reg) {
 452         case MMC35240_REG_CTRL0:
 453         case MMC35240_REG_CTRL1:
 454                 return false;
 455         default:
 456                 return true;
 457         }
 458 }
 459
 460 static const struct reg_default mmc35240_reg_defaults[] = {
 461         { MMC35240_REG_CTRL0,  0x00 },
 462         { MMC35240_REG_CTRL1,  0x00 },
 463 };
 464
 465 static const struct regmap_config mmc35240_regmap_config = {
 466         .name = MMC35240_REGMAP_NAME,
 467
 468         .reg_bits = 8,
 469         .val_bits = 8,
 470
 471         .max_register = MMC35240_REG_ID,
 472         .cache_type = REGCACHE_FLAT,
 473
 474         .writeable_reg = mmc35240_is_writeable_reg,
 475         .readable_reg = mmc35240_is_readable_reg,
 476         .volatile_reg = mmc35240_is_volatile_reg,
 477
 478         .reg_defaults = mmc35240_reg_defaults,
 479         .num_reg_defaults = ARRAY_SIZE(mmc35240_reg_defaults),
 480 };
 481
 482 static int mmc35240_probe(struct i2c_client *client)
 483 {
 484         struct mmc35240_data *data;
 485         struct iio_dev *indio_dev;
 486         struct regmap *regmap;
 487         int ret;
 488
 489         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 490         if (!indio_dev)
 491                 return -ENOMEM;
 492
 493         regmap = devm_regmap_init_i2c(client, &mmc35240_regmap_config);
 494         if (IS_ERR(regmap)) {
 495                 dev_err(&client->dev, "regmap initialization failed\n");
 496                 return PTR_ERR(regmap);
 497         }
 498
 499         data = iio_priv(indio_dev);
 500         i2c_set_clientdata(client, indio_dev);
 501         data->client = client;
 502         data->regmap = regmap;
 503         data->res = MMC35240_16_BITS_SLOW;
 504
 505         mutex_init(&data->mutex);
 506
 507         indio_dev->info = &mmc35240_info;
 508         indio_dev->name = MMC35240_DRV_NAME;
 509         indio_dev->channels = mmc35240_channels;
 510         indio_dev->num_channels = ARRAY_SIZE(mmc35240_channels);
 511         indio_dev->modes = INDIO_DIRECT_MODE;
 512
 513         ret = mmc35240_init(data);
 514         if (ret < 0) {
 515                 dev_err(&client->dev, "mmc35240 chip init failed\n");
 516                 return ret;
 517         }
 518         return devm_iio_device_register(&client->dev, indio_dev);
 519 }
 520
 521 static int mmc35240_suspend(struct device *dev)
 522 {
 523         struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
 524         struct mmc35240_data *data = iio_priv(indio_dev);
 525
 526         regcache_cache_only(data->regmap, true);
 527
 528         return 0;
 529 }
 530
 531 static int mmc35240_resume(struct device *dev)
 532 {
 533         struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
 534         struct mmc35240_data *data = iio_priv(indio_dev);
 535         int ret;
 536
 537         regcache_mark_dirty(data->regmap);
 538         ret = regcache_sync_region(data->regmap, MMC35240_REG_CTRL0,
 539                                    MMC35240_REG_CTRL1);
 540         if (ret < 0)
 541                 dev_err(dev, "Failed to restore control registers\n");
 542
 543         regcache_cache_only(data->regmap, false);
 544
 545         return 0;
 546 }
 547
 548 static DEFINE_SIMPLE_DEV_PM_OPS(mmc35240_pm_ops, mmc35240_suspend,
 549                                 mmc35240_resume);
 550
 551 static const struct of_device_id mmc35240_of_match[] = {
 552         { .compatible = "memsic,mmc35240", },
 553         { }
 554 };
 555 MODULE_DEVICE_TABLE(of, mmc35240_of_match);
 556
 557 static const struct acpi_device_id mmc35240_acpi_match[] = {
 558         {"MMC35240", 0},
 559         { },
 560 };
 561 MODULE_DEVICE_TABLE(acpi, mmc35240_acpi_match);
 562
 563 static const struct i2c_device_id mmc35240_id[] = {
 564         { "mmc35240" },
 565         {}
 566 };
 567 MODULE_DEVICE_TABLE(i2c, mmc35240_id);
 568
 569 static struct i2c_driver mmc35240_driver = {
 570         .driver = {
 571                 .name = MMC35240_DRV_NAME,
 572                 .of_match_table = mmc35240_of_match,
 573                 .pm = pm_sleep_ptr(&mmc35240_pm_ops),
 574                 .acpi_match_table = mmc35240_acpi_match,
 575         },
 576         .probe          = mmc35240_probe,
 577         .id_table       = mmc35240_id,
 578 };
 579
 580 module_i2c_driver(mmc35240_driver);
 581
 582 MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com>");
 583 MODULE_DESCRIPTION("MEMSIC MMC35240 magnetic sensor driver");
 584 MODULE_LICENSE("GPL v2");