drivers/iio/magnetometer/mmc35240.c

   1 /*
   2  * MMC35240 - MEMSIC 3-axis Magnetic Sensor
   3  *
   4  * Copyright (c) 2015, Intel Corporation.
   5  *
   6  * This file is subject to the terms and conditions of version 2 of
   7  * the GNU General Public License.  See the file COPYING in the main
   8  * directory of this archive for more details.
   9  *
  10  * IIO driver for MMC35240 (7-bit I2C slave address 0x30).
  11  *
  12  * TODO: offset, ACPI, continuous measurement mode, PM
  13  */
  14
  15 #include <linux/module.h>
  16 #include <linux/init.h>
  17 #include <linux/i2c.h>
  18 #include <linux/delay.h>
  19 #include <linux/regmap.h>
  20 #include <linux/acpi.h>
  21 #include <linux/pm.h>
  22
  23 #include <linux/iio/iio.h>
  24 #include <linux/iio/sysfs.h>
  25
  26 #define MMC35240_DRV_NAME "mmc35240"
  27 #define MMC35240_REGMAP_NAME "mmc35240_regmap"
  28
  29 #define MMC35240_REG_XOUT_L     0x00
  30 #define MMC35240_REG_XOUT_H     0x01
  31 #define MMC35240_REG_YOUT_L     0x02
  32 #define MMC35240_REG_YOUT_H     0x03
  33 #define MMC35240_REG_ZOUT_L     0x04
  34 #define MMC35240_REG_ZOUT_H     0x05
  35
  36 #define MMC35240_REG_STATUS     0x06
  37 #define MMC35240_REG_CTRL0      0x07
  38 #define MMC35240_REG_CTRL1      0x08
  39
  40 #define MMC35240_REG_ID         0x20
  41
  42 #define MMC35240_STATUS_MEAS_DONE_BIT   BIT(0)
  43
  44 #define MMC35240_CTRL0_REFILL_BIT       BIT(7)
  45 #define MMC35240_CTRL0_RESET_BIT        BIT(6)
  46 #define MMC35240_CTRL0_SET_BIT          BIT(5)
  47 #define MMC35240_CTRL0_CMM_BIT          BIT(1)
  48 #define MMC35240_CTRL0_TM_BIT           BIT(0)
  49
  50 /* output resolution bits */
  51 #define MMC35240_CTRL1_BW0_BIT          BIT(0)
  52 #define MMC35240_CTRL1_BW1_BIT          BIT(1)
  53
  54 #define MMC35240_CTRL1_BW_MASK   (MMC35240_CTRL1_BW0_BIT | \
  55                  MMC35240_CTRL1_BW1_BIT)
  56 #define MMC35240_CTRL1_BW_SHIFT         0
  57
  58 #define MMC35240_WAIT_CHARGE_PUMP       50000   /* us */
  59 #define MMC53240_WAIT_SET_RESET         1000    /* us */
  60
  61 enum mmc35240_resolution {
  62         MMC35240_16_BITS_SLOW = 0, /* 100 Hz */
  63         MMC35240_16_BITS_FAST,     /* 200 Hz */
  64         MMC35240_14_BITS,          /* 333 Hz */
  65         MMC35240_12_BITS,          /* 666 Hz */
  66 };
  67
  68 enum mmc35240_axis {
  69         AXIS_X = 0,
  70         AXIS_Y,
  71         AXIS_Z,
  72 };
  73
  74 static const struct {
  75         int sens[3]; /* sensitivity per X, Y, Z axis */
  76         int nfo; /* null field output */
  77 } mmc35240_props_table[] = {
  78         /* 16 bits, 100Hz ODR */
  79         {
  80                 {1024, 1024, 770},
  81                 32768,
  82         },
  83         /* 16 bits, 200Hz ODR */
  84         {
  85                 {1024, 1024, 770},
  86                 32768,
  87         },
  88         /* 14 bits, 333Hz ODR */
  89         {
  90                 {256, 256, 193},
  91                 8192,
  92         },
  93         /* 12 bits, 666Hz ODR */
  94         {
  95                 {64, 64, 48},
  96                 2048,
  97         },
  98 };
  99
 100 struct mmc35240_data {
 101         struct i2c_client *client;
 102         struct mutex mutex;
 103         struct regmap *regmap;
 104         enum mmc35240_resolution res;
 105 };
 106
 107 static const int mmc35240_samp_freq[] = {100, 200, 333, 666};
 108
 109 static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("100 200 333 666");
 110
 111 #define MMC35240_CHANNEL(_axis) { \
 112         .type = IIO_MAGN, \
 113         .modified = 1, \
 114         .channel2 = IIO_MOD_ ## _axis, \
 115         .address = AXIS_ ## _axis, \
 116         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
 117         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ) | \
 118                         BIT(IIO_CHAN_INFO_SCALE), \
 119 }
 120
 121 static const struct iio_chan_spec mmc35240_channels[] = {
 122         MMC35240_CHANNEL(X),
 123         MMC35240_CHANNEL(Y),
 124         MMC35240_CHANNEL(Z),
 125 };
 126
 127 static struct attribute *mmc35240_attributes[] = {
 128         &iio_const_attr_sampling_frequency_available.dev_attr.attr,
 129         NULL
 130 };
 131
 132 static const struct attribute_group mmc35240_attribute_group = {
 133         .attrs = mmc35240_attributes,
 134 };
 135
 136 static int mmc35240_get_samp_freq_index(struct mmc35240_data *data,
 137                                         int val, int val2)
 138 {
 139         int i;
 140
 141         for (i = 0; i < ARRAY_SIZE(mmc35240_samp_freq); i++)
 142                 if (mmc35240_samp_freq[i] == val)
 143                         return i;
 144         return -EINVAL;
 145 }
 146
 147 static int mmc35240_hw_set(struct mmc35240_data *data, bool set)
 148 {
 149         int ret;
 150         u8 coil_bit;
 151
 152         /*
 153          * Recharge the capacitor at VCAP pin, requested to be issued
 154          * before a SET/RESET command.
 155          */
 156         ret = regmap_update_bits(data->regmap, MMC35240_REG_CTRL0,
 157                                  MMC35240_CTRL0_REFILL_BIT,
 158                                  MMC35240_CTRL0_REFILL_BIT);
 159         if (ret < 0)
 160                 return ret;
 161         usleep_range(MMC35240_WAIT_CHARGE_PUMP, MMC35240_WAIT_CHARGE_PUMP + 1);
 162
 163         if (set)
 164                 coil_bit = MMC35240_CTRL0_SET_BIT;
 165         else
 166                 coil_bit = MMC35240_CTRL0_RESET_BIT;
 167
 168         return regmap_update_bits(data->regmap, MMC35240_REG_CTRL0,
 169                                   MMC35240_CTRL0_REFILL_BIT,
 170                                   coil_bit);
 171 }
 172
 173 static int mmc35240_init(struct mmc35240_data *data)
 174 {
 175         int ret;
 176         unsigned int reg_id;
 177
 178         ret = regmap_read(data->regmap, MMC35240_REG_ID, &reg_id);
 179         if (ret < 0) {
 180                 dev_err(&data->client->dev, "Error reading product id\n");
 181                 return ret;
 182         }
 183
 184         dev_dbg(&data->client->dev, "MMC35240 chip id %x\n", reg_id);
 185
 186         /*
 187          * make sure we restore sensor characteristics, by doing
 188          * a RESET/SET sequence
 189          */
 190         ret = mmc35240_hw_set(data, false);
 191         if (ret < 0)
 192                 return ret;
 193         usleep_range(MMC53240_WAIT_SET_RESET, MMC53240_WAIT_SET_RESET + 1);
 194
 195         ret = mmc35240_hw_set(data, true);
 196         if (ret < 0)
 197                 return ret;
 198
 199         /* set default sampling frequency */
 200         return regmap_update_bits(data->regmap, MMC35240_REG_CTRL1,
 201                                   MMC35240_CTRL1_BW_MASK,
 202                                   data->res << MMC35240_CTRL1_BW_SHIFT);
 203 }
 204
 205 static int mmc35240_take_measurement(struct mmc35240_data *data)
 206 {
 207         int ret, tries = 100;
 208         unsigned int reg_status;
 209
 210         ret = regmap_write(data->regmap, MMC35240_REG_CTRL0,
 211                            MMC35240_CTRL0_TM_BIT);
 212         if (ret < 0)
 213                 return ret;
 214
 215         while (tries-- > 0) {
 216                 ret = regmap_read(data->regmap, MMC35240_REG_STATUS,
 217                                   &reg_status);
 218                 if (ret < 0)
 219                         return ret;
 220                 if (reg_status & MMC35240_STATUS_MEAS_DONE_BIT)
 221                         break;
 222                 msleep(20);
 223         }
 224
 225         if (tries < 0) {
 226                 dev_err(&data->client->dev, "data not ready\n");
 227                 return -EIO;
 228         }
 229
 230         return 0;
 231 }
 232
 233 static int mmc35240_read_measurement(struct mmc35240_data *data, __le16 buf[3])
 234 {
 235         int ret;
 236
 237         ret = mmc35240_take_measurement(data);
 238         if (ret < 0)
 239                 return ret;
 240
 241         return regmap_bulk_read(data->regmap, MMC35240_REG_XOUT_L, (u8 *)buf,
 242                                 3 * sizeof(__le16));
 243 }
 244
 245 /**
 246  * mmc35240_raw_to_mgauss - convert raw readings to milli gauss. Also apply
 247                             compensation for output value.
 248  *
 249  * @data: device private data
 250  * @index: axis index for which we want the conversion
 251  * @buf: raw data to be converted, 2 bytes in little endian format
 252  * @val: compensated output reading (unit is milli gauss)
 253  *
 254  * Returns: 0 in case of success, -EINVAL when @index is not valid
 255  */
 256 static int mmc35240_raw_to_mgauss(struct mmc35240_data *data, int index,
 257                                   __le16 buf[], int *val)
 258 {
 259         int raw_x, raw_y, raw_z;
 260         int sens_x, sens_y, sens_z;
 261         int nfo;
 262
 263         raw_x = le16_to_cpu(buf[AXIS_X]);
 264         raw_y = le16_to_cpu(buf[AXIS_Y]);
 265         raw_z = le16_to_cpu(buf[AXIS_Z]);
 266
 267         sens_x = mmc35240_props_table[data->res].sens[AXIS_X];
 268         sens_y = mmc35240_props_table[data->res].sens[AXIS_Y];
 269         sens_z = mmc35240_props_table[data->res].sens[AXIS_Z];
 270
 271         nfo = mmc35240_props_table[data->res].nfo;
 272
 273         switch (index) {
 274         case AXIS_X:
 275                 *val = (raw_x - nfo) * 1000 / sens_x;
 276                 break;
 277         case AXIS_Y:
 278                 *val = (raw_y - nfo) * 1000 / sens_y -
 279                         (raw_z - nfo)  * 1000 / sens_z;
 280                 break;
 281         case AXIS_Z:
 282                 *val = (raw_y - nfo) * 1000 / sens_y +
 283                         (raw_z - nfo) * 1000 / sens_z;
 284                 break;
 285         default:
 286                 return -EINVAL;
 287         }
 288         return 0;
 289 }
 290
 291 static int mmc35240_read_raw(struct iio_dev *indio_dev,
 292                              struct iio_chan_spec const *chan, int *val,
 293                              int *val2, long mask)
 294 {
 295         struct mmc35240_data *data = iio_priv(indio_dev);
 296         int ret, i;
 297         unsigned int reg;
 298         __le16 buf[3];
 299
 300         switch (mask) {
 301         case IIO_CHAN_INFO_RAW:
 302                 mutex_lock(&data->mutex);
 303                 ret = mmc35240_read_measurement(data, buf);
 304                 mutex_unlock(&data->mutex);
 305                 if (ret < 0)
 306                         return ret;
 307                 ret = mmc35240_raw_to_mgauss(data, chan->address, buf, val);
 308                 if (ret < 0)
 309                         return ret;
 310                 return IIO_VAL_INT;
 311         case IIO_CHAN_INFO_SCALE:
 312                 *val = 0;
 313                 *val2 = 1000;
 314                 return IIO_VAL_INT_PLUS_MICRO;
 315         case IIO_CHAN_INFO_SAMP_FREQ:
 316                 mutex_lock(&data->mutex);
 317                 ret = regmap_read(data->regmap, MMC35240_REG_CTRL1, &reg);
 318                 mutex_unlock(&data->mutex);
 319                 if (ret < 0)
 320                         return ret;
 321
 322                 i = (reg & MMC35240_CTRL1_BW_MASK) >> MMC35240_CTRL1_BW_SHIFT;
 323                 if (i < 0 || i >= ARRAY_SIZE(mmc35240_samp_freq))
 324                         return -EINVAL;
 325
 326                 *val = mmc35240_samp_freq[i];
 327                 *val2 = 0;
 328                 return IIO_VAL_INT;
 329         default:
 330                 return -EINVAL;
 331         }
 332 }
 333
 334 static int mmc35240_write_raw(struct iio_dev *indio_dev,
 335                               struct iio_chan_spec const *chan, int val,
 336                               int val2, long mask)
 337 {
 338         struct mmc35240_data *data = iio_priv(indio_dev);
 339         int i, ret;
 340
 341         switch (mask) {
 342         case IIO_CHAN_INFO_SAMP_FREQ:
 343                 i = mmc35240_get_samp_freq_index(data, val, val2);
 344                 if (i < 0)
 345                         return -EINVAL;
 346                 mutex_lock(&data->mutex);
 347                 ret = regmap_update_bits(data->regmap, MMC35240_REG_CTRL1,
 348                                          MMC35240_CTRL1_BW_MASK,
 349                                          i << MMC35240_CTRL1_BW_SHIFT);
 350                 mutex_unlock(&data->mutex);
 351                 return ret;
 352         default:
 353                 return -EINVAL;
 354         }
 355 }
 356
 357 static const struct iio_info mmc35240_info = {
 358         .driver_module  = THIS_MODULE,
 359         .read_raw       = mmc35240_read_raw,
 360         .write_raw      = mmc35240_write_raw,
 361         .attrs          = &mmc35240_attribute_group,
 362 };
 363
 364 static bool mmc35240_is_writeable_reg(struct device *dev, unsigned int reg)
 365 {
 366         switch (reg) {
 367         case MMC35240_REG_CTRL0:
 368         case MMC35240_REG_CTRL1:
 369                 return true;
 370         default:
 371                 return false;
 372         }
 373 }
 374
 375 static bool mmc35240_is_readable_reg(struct device *dev, unsigned int reg)
 376 {
 377         switch (reg) {
 378         case MMC35240_REG_XOUT_L:
 379         case MMC35240_REG_XOUT_H:
 380         case MMC35240_REG_YOUT_L:
 381         case MMC35240_REG_YOUT_H:
 382         case MMC35240_REG_ZOUT_L:
 383         case MMC35240_REG_ZOUT_H:
 384         case MMC35240_REG_STATUS:
 385         case MMC35240_REG_ID:
 386                 return true;
 387         default:
 388                 return false;
 389         }
 390 }
 391
 392 static bool mmc35240_is_volatile_reg(struct device *dev, unsigned int reg)
 393 {
 394         switch (reg) {
 395         case MMC35240_REG_CTRL0:
 396         case MMC35240_REG_CTRL1:
 397                 return false;
 398         default:
 399                 return true;
 400         }
 401 }
 402
 403 static struct reg_default mmc35240_reg_defaults[] = {
 404         { MMC35240_REG_CTRL0,  0x00 },
 405         { MMC35240_REG_CTRL1,  0x00 },
 406 };
 407
 408 static const struct regmap_config mmc35240_regmap_config = {
 409         .name = MMC35240_REGMAP_NAME,
 410
 411         .reg_bits = 8,
 412         .val_bits = 8,
 413
 414         .max_register = MMC35240_REG_ID,
 415         .cache_type = REGCACHE_FLAT,
 416
 417         .writeable_reg = mmc35240_is_writeable_reg,
 418         .readable_reg = mmc35240_is_readable_reg,
 419         .volatile_reg = mmc35240_is_volatile_reg,
 420
 421         .reg_defaults = mmc35240_reg_defaults,
 422         .num_reg_defaults = ARRAY_SIZE(mmc35240_reg_defaults),
 423 };
 424
 425 static int mmc35240_probe(struct i2c_client *client,
 426                           const struct i2c_device_id *id)
 427 {
 428         struct mmc35240_data *data;
 429         struct iio_dev *indio_dev;
 430         struct regmap *regmap;
 431         int ret;
 432
 433         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 434         if (!indio_dev)
 435                 return -ENOMEM;
 436
 437         regmap = devm_regmap_init_i2c(client, &mmc35240_regmap_config);
 438         if (IS_ERR(regmap)) {
 439                 dev_err(&client->dev, "regmap initialization failed\n");
 440                 return PTR_ERR(regmap);
 441         }
 442
 443         data = iio_priv(indio_dev);
 444         data->client = client;
 445         data->regmap = regmap;
 446         data->res = MMC35240_16_BITS_SLOW;
 447
 448         mutex_init(&data->mutex);
 449
 450         indio_dev->dev.parent = &client->dev;
 451         indio_dev->info = &mmc35240_info;
 452         indio_dev->name = MMC35240_DRV_NAME;
 453         indio_dev->channels = mmc35240_channels;
 454         indio_dev->num_channels = ARRAY_SIZE(mmc35240_channels);
 455         indio_dev->modes = INDIO_DIRECT_MODE;
 456
 457         ret = mmc35240_init(data);
 458         if (ret < 0) {
 459                 dev_err(&client->dev, "mmc35240 chip init failed\n");
 460                 return ret;
 461         }
 462         return devm_iio_device_register(&client->dev, indio_dev);
 463 }
 464
 465 #ifdef CONFIG_PM_SLEEP
 466 static int mmc35240_suspend(struct device *dev)
 467 {
 468         struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
 469         struct mmc35240_data *data = iio_priv(indio_dev);
 470
 471         regcache_cache_only(data->regmap, true);
 472
 473         return 0;
 474 }
 475
 476 static int mmc35240_resume(struct device *dev)
 477 {
 478         struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
 479         struct mmc35240_data *data = iio_priv(indio_dev);
 480         int ret;
 481
 482         regcache_mark_dirty(data->regmap);
 483         ret = regcache_sync_region(data->regmap, MMC35240_REG_CTRL0,
 484                                    MMC35240_REG_CTRL1);
 485         if (ret < 0)
 486                 dev_err(dev, "Failed to restore control registers\n");
 487
 488         regcache_cache_only(data->regmap, false);
 489
 490         return 0;
 491 }
 492 #endif
 493
 494 static const struct dev_pm_ops mmc35240_pm_ops = {
 495         SET_SYSTEM_SLEEP_PM_OPS(mmc35240_suspend, mmc35240_resume)
 496 };
 497
 498 static const struct acpi_device_id mmc35240_acpi_match[] = {
 499         {"MMC35240", 0},
 500         { },
 501 };
 502 MODULE_DEVICE_TABLE(acpi, mmc35240_acpi_match);
 503
 504 static const struct i2c_device_id mmc35240_id[] = {
 505         {"mmc35240", 0},
 506         {}
 507 };
 508 MODULE_DEVICE_TABLE(i2c, mmc35240_id);
 509
 510 static struct i2c_driver mmc35240_driver = {
 511         .driver = {
 512                 .name = MMC35240_DRV_NAME,
 513                 .pm = &mmc35240_pm_ops,
 514                 .acpi_match_table = ACPI_PTR(mmc35240_acpi_match),
 515         },
 516         .probe          = mmc35240_probe,
 517         .id_table       = mmc35240_id,
 518 };
 519
 520 module_i2c_driver(mmc35240_driver);
 521
 522 MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com>");
 523 MODULE_DESCRIPTION("MEMSIC MMC35240 magnetic sensor driver");
 524 MODULE_LICENSE("GPL v2");