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_PROCESSED), \
 117         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ), \
 118 }
 119
 120 static const struct iio_chan_spec mmc35240_channels[] = {
 121         MMC35240_CHANNEL(X),
 122         MMC35240_CHANNEL(Y),
 123         MMC35240_CHANNEL(Z),
 124 };
 125
 126 static struct attribute *mmc35240_attributes[] = {
 127         &iio_const_attr_sampling_frequency_available.dev_attr.attr,
 128         NULL
 129 };
 130
 131 static const struct attribute_group mmc35240_attribute_group = {
 132         .attrs = mmc35240_attributes,
 133 };
 134
 135 static int mmc35240_get_samp_freq_index(struct mmc35240_data *data,
 136                                         int val, int val2)
 137 {
 138         int i;
 139
 140         for (i = 0; i < ARRAY_SIZE(mmc35240_samp_freq); i++)
 141                 if (mmc35240_samp_freq[i] == val)
 142                         return i;
 143         return -EINVAL;
 144 }
 145
 146 static int mmc35240_hw_set(struct mmc35240_data *data, bool set)
 147 {
 148         int ret;
 149         u8 coil_bit;
 150
 151         /*
 152          * Recharge the capacitor at VCAP pin, requested to be issued
 153          * before a SET/RESET command.
 154          */
 155         ret = regmap_update_bits(data->regmap, MMC35240_REG_CTRL0,
 156                                  MMC35240_CTRL0_REFILL_BIT,
 157                                  MMC35240_CTRL0_REFILL_BIT);
 158         if (ret < 0)
 159                 return ret;
 160         usleep_range(MMC35240_WAIT_CHARGE_PUMP, MMC35240_WAIT_CHARGE_PUMP + 1);
 161
 162         if (set)
 163                 coil_bit = MMC35240_CTRL0_SET_BIT;
 164         else
 165                 coil_bit = MMC35240_CTRL0_RESET_BIT;
 166
 167         return regmap_update_bits(data->regmap, MMC35240_REG_CTRL0,
 168                                   MMC35240_CTRL0_REFILL_BIT,
 169                                   coil_bit);
 170 }
 171
 172 static int mmc35240_init(struct mmc35240_data *data)
 173 {
 174         int ret;
 175         unsigned int reg_id;
 176
 177         ret = regmap_read(data->regmap, MMC35240_REG_ID, &reg_id);
 178         if (ret < 0) {
 179                 dev_err(&data->client->dev, "Error reading product id\n");
 180                 return ret;
 181         }
 182
 183         dev_dbg(&data->client->dev, "MMC35240 chip id %x\n", reg_id);
 184
 185         /*
 186          * make sure we restore sensor characteristics, by doing
 187          * a RESET/SET sequence
 188          */
 189         ret = mmc35240_hw_set(data, false);
 190         if (ret < 0)
 191                 return ret;
 192         usleep_range(MMC53240_WAIT_SET_RESET, MMC53240_WAIT_SET_RESET + 1);
 193
 194         ret = mmc35240_hw_set(data, true);
 195         if (ret < 0)
 196                 return ret;
 197
 198         /* set default sampling frequency */
 199         return regmap_update_bits(data->regmap, MMC35240_REG_CTRL1,
 200                                   MMC35240_CTRL1_BW_MASK,
 201                                   data->res << MMC35240_CTRL1_BW_SHIFT);
 202 }
 203
 204 static int mmc35240_take_measurement(struct mmc35240_data *data)
 205 {
 206         int ret, tries = 100;
 207         unsigned int reg_status;
 208
 209         ret = regmap_write(data->regmap, MMC35240_REG_CTRL0,
 210                            MMC35240_CTRL0_TM_BIT);
 211         if (ret < 0)
 212                 return ret;
 213
 214         while (tries-- > 0) {
 215                 ret = regmap_read(data->regmap, MMC35240_REG_STATUS,
 216                                   &reg_status);
 217                 if (ret < 0)
 218                         return ret;
 219                 if (reg_status & MMC35240_STATUS_MEAS_DONE_BIT)
 220                         break;
 221                 msleep(20);
 222         }
 223
 224         if (tries < 0) {
 225                 dev_err(&data->client->dev, "data not ready\n");
 226                 return -EIO;
 227         }
 228
 229         return 0;
 230 }
 231
 232 static int mmc35240_read_measurement(struct mmc35240_data *data, __le16 buf[3])
 233 {
 234         int ret;
 235
 236         ret = mmc35240_take_measurement(data);
 237         if (ret < 0)
 238                 return ret;
 239
 240         return regmap_bulk_read(data->regmap, MMC35240_REG_XOUT_L, (u8 *)buf,
 241                                 3 * sizeof(__le16));
 242 }
 243
 244 static int mmc35240_raw_to_gauss(struct mmc35240_data *data, int index,
 245                                  __le16 buf[],
 246                                  int *val, int *val2)
 247 {
 248         int raw_x, raw_y, raw_z;
 249         int sens_x, sens_y, sens_z;
 250         int nfo;
 251
 252         raw_x = le16_to_cpu(buf[AXIS_X]);
 253         raw_y = le16_to_cpu(buf[AXIS_Y]);
 254         raw_z = le16_to_cpu(buf[AXIS_Z]);
 255
 256         sens_x = mmc35240_props_table[data->res].sens[AXIS_X];
 257         sens_y = mmc35240_props_table[data->res].sens[AXIS_Y];
 258         sens_z = mmc35240_props_table[data->res].sens[AXIS_Z];
 259
 260         nfo = mmc35240_props_table[data->res].nfo;
 261
 262         switch (index) {
 263         case AXIS_X:
 264                 *val = (raw_x - nfo) / sens_x;
 265                 *val2 = ((raw_x - nfo) % sens_x) * 1000000;
 266                 break;
 267         case AXIS_Y:
 268                 *val = (raw_y - nfo) / sens_y - (raw_z - nfo) / sens_z;
 269                 *val2 = (((raw_y - nfo) % sens_y - (raw_z - nfo) % sens_z))
 270                         * 1000000;
 271                 break;
 272         case AXIS_Z:
 273                 *val = (raw_y - nfo) / sens_y + (raw_z - nfo) / sens_z;
 274                 *val2 = (((raw_y - nfo) % sens_y + (raw_z - nfo) % sens_z))
 275                         * 1000000;
 276                 break;
 277         default:
 278                 return -EINVAL;
 279         }
 280         return 0;
 281 }
 282
 283 static int mmc35240_read_raw(struct iio_dev *indio_dev,
 284                              struct iio_chan_spec const *chan, int *val,
 285                              int *val2, long mask)
 286 {
 287         struct mmc35240_data *data = iio_priv(indio_dev);
 288         int ret, i;
 289         unsigned int reg;
 290         __le16 buf[3];
 291
 292         switch (mask) {
 293         case IIO_CHAN_INFO_PROCESSED:
 294                 mutex_lock(&data->mutex);
 295                 ret = mmc35240_read_measurement(data, buf);
 296                 mutex_unlock(&data->mutex);
 297                 if (ret < 0)
 298                         return ret;
 299                 ret = mmc35240_raw_to_gauss(data, chan->address,
 300                                             buf, val, val2);
 301                 if (ret < 0)
 302                         return ret;
 303                 return IIO_VAL_INT_PLUS_MICRO;
 304         case IIO_CHAN_INFO_SAMP_FREQ:
 305                 mutex_lock(&data->mutex);
 306                 ret = regmap_read(data->regmap, MMC35240_REG_CTRL1, &reg);
 307                 mutex_unlock(&data->mutex);
 308                 if (ret < 0)
 309                         return ret;
 310
 311                 i = (reg & MMC35240_CTRL1_BW_MASK) >> MMC35240_CTRL1_BW_SHIFT;
 312                 if (i < 0 || i >= ARRAY_SIZE(mmc35240_samp_freq))
 313                         return -EINVAL;
 314
 315                 *val = mmc35240_samp_freq[i];
 316                 *val2 = 0;
 317                 return IIO_VAL_INT;
 318         default:
 319                 return -EINVAL;
 320         }
 321 }
 322
 323 static int mmc35240_write_raw(struct iio_dev *indio_dev,
 324                               struct iio_chan_spec const *chan, int val,
 325                               int val2, long mask)
 326 {
 327         struct mmc35240_data *data = iio_priv(indio_dev);
 328         int i, ret;
 329
 330         switch (mask) {
 331         case IIO_CHAN_INFO_SAMP_FREQ:
 332                 i = mmc35240_get_samp_freq_index(data, val, val2);
 333                 if (i < 0)
 334                         return -EINVAL;
 335                 mutex_lock(&data->mutex);
 336                 ret = regmap_update_bits(data->regmap, MMC35240_REG_CTRL1,
 337                                          MMC35240_CTRL1_BW_MASK,
 338                                          i << MMC35240_CTRL1_BW_SHIFT);
 339                 mutex_unlock(&data->mutex);
 340                 return ret;
 341         default:
 342                 return -EINVAL;
 343         }
 344 }
 345
 346 static const struct iio_info mmc35240_info = {
 347         .driver_module  = THIS_MODULE,
 348         .read_raw       = mmc35240_read_raw,
 349         .write_raw      = mmc35240_write_raw,
 350         .attrs          = &mmc35240_attribute_group,
 351 };
 352
 353 static bool mmc35240_is_writeable_reg(struct device *dev, unsigned int reg)
 354 {
 355         switch (reg) {
 356         case MMC35240_REG_CTRL0:
 357         case MMC35240_REG_CTRL1:
 358                 return true;
 359         default:
 360                 return false;
 361         }
 362 }
 363
 364 static bool mmc35240_is_readable_reg(struct device *dev, unsigned int reg)
 365 {
 366         switch (reg) {
 367         case MMC35240_REG_XOUT_L:
 368         case MMC35240_REG_XOUT_H:
 369         case MMC35240_REG_YOUT_L:
 370         case MMC35240_REG_YOUT_H:
 371         case MMC35240_REG_ZOUT_L:
 372         case MMC35240_REG_ZOUT_H:
 373         case MMC35240_REG_STATUS:
 374         case MMC35240_REG_ID:
 375                 return true;
 376         default:
 377                 return false;
 378         }
 379 }
 380
 381 static bool mmc35240_is_volatile_reg(struct device *dev, unsigned int reg)
 382 {
 383         switch (reg) {
 384         case MMC35240_REG_CTRL0:
 385         case MMC35240_REG_CTRL1:
 386                 return false;
 387         default:
 388                 return true;
 389         }
 390 }
 391
 392 static struct reg_default mmc35240_reg_defaults[] = {
 393         { MMC35240_REG_CTRL0,  0x00 },
 394         { MMC35240_REG_CTRL1,  0x00 },
 395 };
 396
 397 static const struct regmap_config mmc35240_regmap_config = {
 398         .name = MMC35240_REGMAP_NAME,
 399
 400         .reg_bits = 8,
 401         .val_bits = 8,
 402
 403         .max_register = MMC35240_REG_ID,
 404         .cache_type = REGCACHE_FLAT,
 405
 406         .writeable_reg = mmc35240_is_writeable_reg,
 407         .readable_reg = mmc35240_is_readable_reg,
 408         .volatile_reg = mmc35240_is_volatile_reg,
 409
 410         .reg_defaults = mmc35240_reg_defaults,
 411         .num_reg_defaults = ARRAY_SIZE(mmc35240_reg_defaults),
 412 };
 413
 414 static int mmc35240_probe(struct i2c_client *client,
 415                           const struct i2c_device_id *id)
 416 {
 417         struct mmc35240_data *data;
 418         struct iio_dev *indio_dev;
 419         struct regmap *regmap;
 420         int ret;
 421
 422         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 423         if (!indio_dev)
 424                 return -ENOMEM;
 425
 426         regmap = devm_regmap_init_i2c(client, &mmc35240_regmap_config);
 427         if (IS_ERR(regmap)) {
 428                 dev_err(&client->dev, "regmap initialization failed\n");
 429                 return PTR_ERR(regmap);
 430         }
 431
 432         data = iio_priv(indio_dev);
 433         data->client = client;
 434         data->regmap = regmap;
 435         data->res = MMC35240_16_BITS_SLOW;
 436
 437         mutex_init(&data->mutex);
 438
 439         indio_dev->dev.parent = &client->dev;
 440         indio_dev->info = &mmc35240_info;
 441         indio_dev->name = MMC35240_DRV_NAME;
 442         indio_dev->channels = mmc35240_channels;
 443         indio_dev->num_channels = ARRAY_SIZE(mmc35240_channels);
 444         indio_dev->modes = INDIO_DIRECT_MODE;
 445
 446         ret = mmc35240_init(data);
 447         if (ret < 0) {
 448                 dev_err(&client->dev, "mmc35240 chip init failed\n");
 449                 return ret;
 450         }
 451         return devm_iio_device_register(&client->dev, indio_dev);
 452 }
 453
 454 #ifdef CONFIG_PM_SLEEP
 455 static int mmc35240_suspend(struct device *dev)
 456 {
 457         struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
 458         struct mmc35240_data *data = iio_priv(indio_dev);
 459
 460         regcache_cache_only(data->regmap, true);
 461
 462         return 0;
 463 }
 464
 465 static int mmc35240_resume(struct device *dev)
 466 {
 467         struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
 468         struct mmc35240_data *data = iio_priv(indio_dev);
 469         int ret;
 470
 471         regcache_mark_dirty(data->regmap);
 472         ret = regcache_sync_region(data->regmap, MMC35240_REG_CTRL0,
 473                                    MMC35240_REG_CTRL1);
 474         if (ret < 0)
 475                 dev_err(dev, "Failed to restore control registers\n");
 476
 477         regcache_cache_only(data->regmap, false);
 478
 479         return 0;
 480 }
 481 #endif
 482
 483 static const struct dev_pm_ops mmc35240_pm_ops = {
 484         SET_SYSTEM_SLEEP_PM_OPS(mmc35240_suspend, mmc35240_resume)
 485 };
 486
 487 static const struct acpi_device_id mmc35240_acpi_match[] = {
 488         {"MMC35240", 0},
 489         { },
 490 };
 491 MODULE_DEVICE_TABLE(acpi, mmc35240_acpi_match);
 492
 493 static const struct i2c_device_id mmc35240_id[] = {
 494         {"mmc35240", 0},
 495         {}
 496 };
 497 MODULE_DEVICE_TABLE(i2c, mmc35240_id);
 498
 499 static struct i2c_driver mmc35240_driver = {
 500         .driver = {
 501                 .name = MMC35240_DRV_NAME,
 502                 .pm = &mmc35240_pm_ops,
 503                 .acpi_match_table = ACPI_PTR(mmc35240_acpi_match),
 504         },
 505         .probe          = mmc35240_probe,
 506         .id_table       = mmc35240_id,
 507 };
 508
 509 module_i2c_driver(mmc35240_driver);
 510
 511 MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com>");
 512 MODULE_DESCRIPTION("MEMSIC MMC35240 magnetic sensor driver");
 513 MODULE_LICENSE("GPL v2");