drivers/iio/magnetometer/mag3110.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * mag3110.c - Support for Freescale MAG3110 magnetometer sensor
   4  *
   5  * Copyright (c) 2013 Peter Meerwald <pmeerw@pmeerw.net>
   6  *
   7  * (7-bit I2C slave address 0x0e)
   8  *
   9  * TODO: irq, user offset, oversampling, continuous mode
  10  */
  11
  12 #include <linux/module.h>
  13 #include <linux/i2c.h>
  14 #include <linux/iio/iio.h>
  15 #include <linux/iio/sysfs.h>
  16 #include <linux/iio/trigger_consumer.h>
  17 #include <linux/iio/buffer.h>
  18 #include <linux/iio/triggered_buffer.h>
  19 #include <linux/delay.h>
  20 #include <linux/regulator/consumer.h>
  21
  22 #define MAG3110_STATUS 0x00
  23 #define MAG3110_OUT_X 0x01 /* MSB first */
  24 #define MAG3110_OUT_Y 0x03
  25 #define MAG3110_OUT_Z 0x05
  26 #define MAG3110_WHO_AM_I 0x07
  27 #define MAG3110_SYSMOD 0x08
  28 #define MAG3110_OFF_X 0x09 /* MSB first */
  29 #define MAG3110_OFF_Y 0x0b
  30 #define MAG3110_OFF_Z 0x0d
  31 #define MAG3110_DIE_TEMP 0x0f
  32 #define MAG3110_CTRL_REG1 0x10
  33 #define MAG3110_CTRL_REG2 0x11
  34
  35 #define MAG3110_STATUS_DRDY (BIT(2) | BIT(1) | BIT(0))
  36
  37 #define MAG3110_CTRL_DR_MASK (BIT(7) | BIT(6) | BIT(5))
  38 #define MAG3110_CTRL_DR_SHIFT 5
  39 #define MAG3110_CTRL_DR_DEFAULT 0
  40
  41 #define MAG3110_SYSMOD_MODE_MASK GENMASK(1, 0)
  42
  43 #define MAG3110_CTRL_TM BIT(1) /* trigger single measurement */
  44 #define MAG3110_CTRL_AC BIT(0) /* continuous measurements */
  45
  46 #define MAG3110_CTRL_AUTO_MRST_EN BIT(7) /* magnetic auto-reset */
  47 #define MAG3110_CTRL_RAW BIT(5) /* measurements not user-offset corrected */
  48
  49 #define MAG3110_DEVICE_ID 0xc4
  50
  51 /* Each client has this additional data */
  52 struct mag3110_data {
  53         struct i2c_client *client;
  54         struct mutex lock;
  55         u8 ctrl_reg1;
  56         int sleep_val;
  57         struct regulator *vdd_reg;
  58         struct regulator *vddio_reg;
  59         /* Ensure natural alignment of timestamp */
  60         struct {
  61                 __be16 channels[3];
  62                 u8 temperature;
  63                 s64 ts __aligned(8);
  64         } scan;
  65 };
  66
  67 static int mag3110_request(struct mag3110_data *data)
  68 {
  69         int ret, tries = 150;
  70
  71         if ((data->ctrl_reg1 & MAG3110_CTRL_AC) == 0) {
  72                 /* trigger measurement */
  73                 ret = i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
  74                         data->ctrl_reg1 | MAG3110_CTRL_TM);
  75                 if (ret < 0)
  76                         return ret;
  77         }
  78
  79         while (tries-- > 0) {
  80                 ret = i2c_smbus_read_byte_data(data->client, MAG3110_STATUS);
  81                 if (ret < 0)
  82                         return ret;
  83                 /* wait for data ready */
  84                 if ((ret & MAG3110_STATUS_DRDY) == MAG3110_STATUS_DRDY)
  85                         break;
  86
  87                 if (data->sleep_val <= 20)
  88                         usleep_range(data->sleep_val * 250, data->sleep_val * 500);
  89                 else
  90                         msleep(20);
  91         }
  92
  93         if (tries < 0) {
  94                 dev_err(&data->client->dev, "data not ready\n");
  95                 return -EIO;
  96         }
  97
  98         return 0;
  99 }
 100
 101 static int mag3110_read(struct mag3110_data *data, __be16 buf[3])
 102 {
 103         int ret;
 104
 105         mutex_lock(&data->lock);
 106         ret = mag3110_request(data);
 107         if (ret < 0) {
 108                 mutex_unlock(&data->lock);
 109                 return ret;
 110         }
 111         ret = i2c_smbus_read_i2c_block_data(data->client,
 112                 MAG3110_OUT_X, 3 * sizeof(__be16), (u8 *) buf);
 113         mutex_unlock(&data->lock);
 114
 115         return ret;
 116 }
 117
 118 static ssize_t mag3110_show_int_plus_micros(char *buf,
 119         const int (*vals)[2], int n)
 120 {
 121         size_t len = 0;
 122
 123         while (n-- > 0)
 124                 len += scnprintf(buf + len, PAGE_SIZE - len,
 125                         "%d.%06d ", vals[n][0], vals[n][1]);
 126
 127         /* replace trailing space by newline */
 128         buf[len - 1] = '\n';
 129
 130         return len;
 131 }
 132
 133 static int mag3110_get_int_plus_micros_index(const int (*vals)[2], int n,
 134                                         int val, int val2)
 135 {
 136         while (n-- > 0)
 137                 if (val == vals[n][0] && val2 == vals[n][1])
 138                         return n;
 139
 140         return -EINVAL;
 141 }
 142
 143 static const int mag3110_samp_freq[8][2] = {
 144         {80, 0}, {40, 0}, {20, 0}, {10, 0}, {5, 0}, {2, 500000},
 145         {1, 250000}, {0, 625000}
 146 };
 147
 148 static ssize_t mag3110_show_samp_freq_avail(struct device *dev,
 149                                 struct device_attribute *attr, char *buf)
 150 {
 151         return mag3110_show_int_plus_micros(buf, mag3110_samp_freq, 8);
 152 }
 153
 154 static IIO_DEV_ATTR_SAMP_FREQ_AVAIL(mag3110_show_samp_freq_avail);
 155
 156 static int mag3110_get_samp_freq_index(struct mag3110_data *data,
 157         int val, int val2)
 158 {
 159         return mag3110_get_int_plus_micros_index(mag3110_samp_freq, 8, val,
 160                 val2);
 161 }
 162
 163 static int mag3110_calculate_sleep(struct mag3110_data *data)
 164 {
 165         int ret, i = data->ctrl_reg1 >> MAG3110_CTRL_DR_SHIFT;
 166
 167         if (mag3110_samp_freq[i][0] > 0)
 168                 ret = 1000 / mag3110_samp_freq[i][0];
 169         else
 170                 ret = 1000;
 171
 172         return ret == 0 ? 1 : ret;
 173 }
 174
 175 static int mag3110_standby(struct mag3110_data *data)
 176 {
 177         return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
 178                 data->ctrl_reg1 & ~MAG3110_CTRL_AC);
 179 }
 180
 181 static int mag3110_wait_standby(struct mag3110_data *data)
 182 {
 183         int ret, tries = 30;
 184
 185         /*
 186          * Takes up to 1/ODR to come out of active mode into stby
 187          * Longest expected period is 12.5seconds.
 188          * We'll sleep for 500ms between checks
 189          */
 190         while (tries-- > 0) {
 191                 ret = i2c_smbus_read_byte_data(data->client, MAG3110_SYSMOD);
 192                 if (ret < 0) {
 193                         dev_err(&data->client->dev, "i2c error\n");
 194                         return ret;
 195                 }
 196                 /* wait for standby */
 197                 if ((ret & MAG3110_SYSMOD_MODE_MASK) == 0)
 198                         break;
 199
 200                 msleep_interruptible(500);
 201         }
 202
 203         if (tries < 0) {
 204                 dev_err(&data->client->dev, "device not entering standby mode\n");
 205                 return -EIO;
 206         }
 207
 208         return 0;
 209 }
 210
 211 static int mag3110_active(struct mag3110_data *data)
 212 {
 213         return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
 214                                          data->ctrl_reg1);
 215 }
 216
 217 /* returns >0 if active, 0 if in standby and <0 on error */
 218 static int mag3110_is_active(struct mag3110_data *data)
 219 {
 220         int reg;
 221
 222         reg = i2c_smbus_read_byte_data(data->client, MAG3110_CTRL_REG1);
 223         if (reg < 0)
 224                 return reg;
 225
 226         return reg & MAG3110_CTRL_AC;
 227 }
 228
 229 static int mag3110_change_config(struct mag3110_data *data, u8 reg, u8 val)
 230 {
 231         int ret;
 232         int is_active;
 233
 234         mutex_lock(&data->lock);
 235
 236         is_active = mag3110_is_active(data);
 237         if (is_active < 0) {
 238                 ret = is_active;
 239                 goto fail;
 240         }
 241
 242         /* config can only be changed when in standby */
 243         if (is_active > 0) {
 244                 ret = mag3110_standby(data);
 245                 if (ret < 0)
 246                         goto fail;
 247         }
 248
 249         /*
 250          * After coming out of active we must wait for the part
 251          * to transition to STBY. This can take up to 1 /ODR to occur
 252          */
 253         ret = mag3110_wait_standby(data);
 254         if (ret < 0)
 255                 goto fail;
 256
 257         ret = i2c_smbus_write_byte_data(data->client, reg, val);
 258         if (ret < 0)
 259                 goto fail;
 260
 261         if (is_active > 0) {
 262                 ret = mag3110_active(data);
 263                 if (ret < 0)
 264                         goto fail;
 265         }
 266
 267         ret = 0;
 268 fail:
 269         mutex_unlock(&data->lock);
 270
 271         return ret;
 272 }
 273
 274 static int mag3110_read_raw(struct iio_dev *indio_dev,
 275                             struct iio_chan_spec const *chan,
 276                             int *val, int *val2, long mask)
 277 {
 278         struct mag3110_data *data = iio_priv(indio_dev);
 279         __be16 buffer[3];
 280         int i, ret;
 281
 282         switch (mask) {
 283         case IIO_CHAN_INFO_RAW:
 284                 ret = iio_device_claim_direct_mode(indio_dev);
 285                 if (ret)
 286                         return ret;
 287
 288                 switch (chan->type) {
 289                 case IIO_MAGN: /* in 0.1 uT / LSB */
 290                         ret = mag3110_read(data, buffer);
 291                         if (ret < 0)
 292                                 goto release;
 293                         *val = sign_extend32(
 294                                 be16_to_cpu(buffer[chan->scan_index]),
 295                                             chan->scan_type.realbits - 1);
 296                         ret = IIO_VAL_INT;
 297                         break;
 298                 case IIO_TEMP: /* in 1 C / LSB */
 299                         mutex_lock(&data->lock);
 300                         ret = mag3110_request(data);
 301                         if (ret < 0) {
 302                                 mutex_unlock(&data->lock);
 303                                 goto release;
 304                         }
 305                         ret = i2c_smbus_read_byte_data(data->client,
 306                                 MAG3110_DIE_TEMP);
 307                         mutex_unlock(&data->lock);
 308                         if (ret < 0)
 309                                 goto release;
 310                         *val = sign_extend32(ret,
 311                                              chan->scan_type.realbits - 1);
 312                         ret = IIO_VAL_INT;
 313                         break;
 314                 default:
 315                         ret = -EINVAL;
 316                 }
 317 release:
 318                 iio_device_release_direct_mode(indio_dev);
 319                 return ret;
 320
 321         case IIO_CHAN_INFO_SCALE:
 322                 switch (chan->type) {
 323                 case IIO_MAGN:
 324                         *val = 0;
 325                         *val2 = 1000;
 326                         return IIO_VAL_INT_PLUS_MICRO;
 327                 case IIO_TEMP:
 328                         *val = 1000;
 329                         return IIO_VAL_INT;
 330                 default:
 331                         return -EINVAL;
 332                 }
 333         case IIO_CHAN_INFO_SAMP_FREQ:
 334                 i = data->ctrl_reg1 >> MAG3110_CTRL_DR_SHIFT;
 335                 *val = mag3110_samp_freq[i][0];
 336                 *val2 = mag3110_samp_freq[i][1];
 337                 return IIO_VAL_INT_PLUS_MICRO;
 338         case IIO_CHAN_INFO_CALIBBIAS:
 339                 ret = i2c_smbus_read_word_swapped(data->client,
 340                         MAG3110_OFF_X + 2 * chan->scan_index);
 341                 if (ret < 0)
 342                         return ret;
 343                 *val = sign_extend32(ret >> 1, 14);
 344                 return IIO_VAL_INT;
 345         }
 346         return -EINVAL;
 347 }
 348
 349 static int mag3110_write_raw(struct iio_dev *indio_dev,
 350                              struct iio_chan_spec const *chan,
 351                              int val, int val2, long mask)
 352 {
 353         struct mag3110_data *data = iio_priv(indio_dev);
 354         int rate, ret;
 355
 356         ret = iio_device_claim_direct_mode(indio_dev);
 357         if (ret)
 358                 return ret;
 359
 360         switch (mask) {
 361         case IIO_CHAN_INFO_SAMP_FREQ:
 362                 rate = mag3110_get_samp_freq_index(data, val, val2);
 363                 if (rate < 0) {
 364                         ret = -EINVAL;
 365                         break;
 366                 }
 367                 data->ctrl_reg1 &= 0xff & ~MAG3110_CTRL_DR_MASK
 368                                         & ~MAG3110_CTRL_AC;
 369                 data->ctrl_reg1 |= rate << MAG3110_CTRL_DR_SHIFT;
 370                 data->sleep_val = mag3110_calculate_sleep(data);
 371                 if (data->sleep_val < 40)
 372                         data->ctrl_reg1 |= MAG3110_CTRL_AC;
 373
 374                 ret = mag3110_change_config(data, MAG3110_CTRL_REG1,
 375                                             data->ctrl_reg1);
 376                 break;
 377         case IIO_CHAN_INFO_CALIBBIAS:
 378                 if (val < -10000 || val > 10000) {
 379                         ret = -EINVAL;
 380                         break;
 381                 }
 382                 ret = i2c_smbus_write_word_swapped(data->client,
 383                         MAG3110_OFF_X + 2 * chan->scan_index, val << 1);
 384                 break;
 385         default:
 386                 ret = -EINVAL;
 387                 break;
 388         }
 389         iio_device_release_direct_mode(indio_dev);
 390         return ret;
 391 }
 392
 393 static irqreturn_t mag3110_trigger_handler(int irq, void *p)
 394 {
 395         struct iio_poll_func *pf = p;
 396         struct iio_dev *indio_dev = pf->indio_dev;
 397         struct mag3110_data *data = iio_priv(indio_dev);
 398         int ret;
 399
 400         ret = mag3110_read(data, data->scan.channels);
 401         if (ret < 0)
 402                 goto done;
 403
 404         if (test_bit(3, indio_dev->active_scan_mask)) {
 405                 ret = i2c_smbus_read_byte_data(data->client,
 406                         MAG3110_DIE_TEMP);
 407                 if (ret < 0)
 408                         goto done;
 409                 data->scan.temperature = ret;
 410         }
 411
 412         iio_push_to_buffers_with_timestamp(indio_dev, &data->scan,
 413                 iio_get_time_ns(indio_dev));
 414
 415 done:
 416         iio_trigger_notify_done(indio_dev->trig);
 417         return IRQ_HANDLED;
 418 }
 419
 420 #define MAG3110_CHANNEL(axis, idx) { \
 421         .type = IIO_MAGN, \
 422         .modified = 1, \
 423         .channel2 = IIO_MOD_##axis, \
 424         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
 425                 BIT(IIO_CHAN_INFO_CALIBBIAS), \
 426         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ) | \
 427                 BIT(IIO_CHAN_INFO_SCALE), \
 428         .scan_index = idx, \
 429         .scan_type = { \
 430                 .sign = 's', \
 431                 .realbits = 16, \
 432                 .storagebits = 16, \
 433                 .endianness = IIO_BE, \
 434         }, \
 435 }
 436
 437 static const struct iio_chan_spec mag3110_channels[] = {
 438         MAG3110_CHANNEL(X, 0),
 439         MAG3110_CHANNEL(Y, 1),
 440         MAG3110_CHANNEL(Z, 2),
 441         {
 442                 .type = IIO_TEMP,
 443                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 444                         BIT(IIO_CHAN_INFO_SCALE),
 445                 .scan_index = 3,
 446                 .scan_type = {
 447                         .sign = 's',
 448                         .realbits = 8,
 449                         .storagebits = 8,
 450                         },
 451         },
 452         IIO_CHAN_SOFT_TIMESTAMP(4),
 453 };
 454
 455 static struct attribute *mag3110_attributes[] = {
 456         &iio_dev_attr_sampling_frequency_available.dev_attr.attr,
 457         NULL
 458 };
 459
 460 static const struct attribute_group mag3110_group = {
 461         .attrs = mag3110_attributes,
 462 };
 463
 464 static const struct iio_info mag3110_info = {
 465         .attrs = &mag3110_group,
 466         .read_raw = &mag3110_read_raw,
 467         .write_raw = &mag3110_write_raw,
 468 };
 469
 470 static const unsigned long mag3110_scan_masks[] = {0x7, 0xf, 0};
 471
 472 static int mag3110_probe(struct i2c_client *client)
 473 {
 474         const struct i2c_device_id *id = i2c_client_get_device_id(client);
 475         struct mag3110_data *data;
 476         struct iio_dev *indio_dev;
 477         int ret;
 478
 479         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 480         if (!indio_dev)
 481                 return -ENOMEM;
 482
 483         data = iio_priv(indio_dev);
 484
 485         data->vdd_reg = devm_regulator_get(&client->dev, "vdd");
 486         if (IS_ERR(data->vdd_reg))
 487                 return dev_err_probe(&client->dev, PTR_ERR(data->vdd_reg),
 488                                      "failed to get VDD regulator!\n");
 489
 490         data->vddio_reg = devm_regulator_get(&client->dev, "vddio");
 491         if (IS_ERR(data->vddio_reg))
 492                 return dev_err_probe(&client->dev, PTR_ERR(data->vddio_reg),
 493                                      "failed to get VDDIO regulator!\n");
 494
 495         ret = regulator_enable(data->vdd_reg);
 496         if (ret) {
 497                 dev_err(&client->dev, "failed to enable VDD regulator!\n");
 498                 return ret;
 499         }
 500
 501         ret = regulator_enable(data->vddio_reg);
 502         if (ret) {
 503                 dev_err(&client->dev, "failed to enable VDDIO regulator!\n");
 504                 goto disable_regulator_vdd;
 505         }
 506
 507         ret = i2c_smbus_read_byte_data(client, MAG3110_WHO_AM_I);
 508         if (ret < 0)
 509                 goto disable_regulators;
 510         if (ret != MAG3110_DEVICE_ID) {
 511                 ret = -ENODEV;
 512                 goto disable_regulators;
 513         }
 514
 515         data->client = client;
 516         mutex_init(&data->lock);
 517
 518         i2c_set_clientdata(client, indio_dev);
 519         indio_dev->info = &mag3110_info;
 520         indio_dev->name = id->name;
 521         indio_dev->modes = INDIO_DIRECT_MODE;
 522         indio_dev->channels = mag3110_channels;
 523         indio_dev->num_channels = ARRAY_SIZE(mag3110_channels);
 524         indio_dev->available_scan_masks = mag3110_scan_masks;
 525
 526         data->ctrl_reg1 = MAG3110_CTRL_DR_DEFAULT << MAG3110_CTRL_DR_SHIFT;
 527         data->sleep_val = mag3110_calculate_sleep(data);
 528         if (data->sleep_val < 40)
 529                 data->ctrl_reg1 |= MAG3110_CTRL_AC;
 530
 531         ret = mag3110_change_config(data, MAG3110_CTRL_REG1, data->ctrl_reg1);
 532         if (ret < 0)
 533                 goto disable_regulators;
 534
 535         ret = i2c_smbus_write_byte_data(client, MAG3110_CTRL_REG2,
 536                 MAG3110_CTRL_AUTO_MRST_EN);
 537         if (ret < 0)
 538                 goto standby_on_error;
 539
 540         ret = iio_triggered_buffer_setup(indio_dev, NULL,
 541                 mag3110_trigger_handler, NULL);
 542         if (ret < 0)
 543                 goto standby_on_error;
 544
 545         ret = iio_device_register(indio_dev);
 546         if (ret < 0)
 547                 goto buffer_cleanup;
 548         return 0;
 549
 550 buffer_cleanup:
 551         iio_triggered_buffer_cleanup(indio_dev);
 552 standby_on_error:
 553         mag3110_standby(iio_priv(indio_dev));
 554 disable_regulators:
 555         regulator_disable(data->vddio_reg);
 556 disable_regulator_vdd:
 557         regulator_disable(data->vdd_reg);
 558
 559         return ret;
 560 }
 561
 562 static void mag3110_remove(struct i2c_client *client)
 563 {
 564         struct iio_dev *indio_dev = i2c_get_clientdata(client);
 565         struct mag3110_data *data = iio_priv(indio_dev);
 566
 567         iio_device_unregister(indio_dev);
 568         iio_triggered_buffer_cleanup(indio_dev);
 569         mag3110_standby(iio_priv(indio_dev));
 570         regulator_disable(data->vddio_reg);
 571         regulator_disable(data->vdd_reg);
 572 }
 573
 574 static int mag3110_suspend(struct device *dev)
 575 {
 576         struct mag3110_data *data = iio_priv(i2c_get_clientdata(
 577                 to_i2c_client(dev)));
 578         int ret;
 579
 580         ret = mag3110_standby(iio_priv(i2c_get_clientdata(
 581                 to_i2c_client(dev))));
 582         if (ret)
 583                 return ret;
 584
 585         ret = regulator_disable(data->vddio_reg);
 586         if (ret) {
 587                 dev_err(dev, "failed to disable VDDIO regulator\n");
 588                 return ret;
 589         }
 590
 591         ret = regulator_disable(data->vdd_reg);
 592         if (ret) {
 593                 dev_err(dev, "failed to disable VDD regulator\n");
 594                 return ret;
 595         }
 596
 597         return 0;
 598 }
 599
 600 static int mag3110_resume(struct device *dev)
 601 {
 602         struct mag3110_data *data = iio_priv(i2c_get_clientdata(
 603                 to_i2c_client(dev)));
 604         int ret;
 605
 606         ret = regulator_enable(data->vdd_reg);
 607         if (ret) {
 608                 dev_err(dev, "failed to enable VDD regulator\n");
 609                 return ret;
 610         }
 611
 612         ret = regulator_enable(data->vddio_reg);
 613         if (ret) {
 614                 dev_err(dev, "failed to enable VDDIO regulator\n");
 615                 regulator_disable(data->vdd_reg);
 616                 return ret;
 617         }
 618
 619         return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
 620                 data->ctrl_reg1);
 621 }
 622
 623 static DEFINE_SIMPLE_DEV_PM_OPS(mag3110_pm_ops, mag3110_suspend,
 624                                 mag3110_resume);
 625
 626 static const struct i2c_device_id mag3110_id[] = {
 627         { "mag3110" },
 628         { }
 629 };
 630 MODULE_DEVICE_TABLE(i2c, mag3110_id);
 631
 632 static const struct of_device_id mag3110_of_match[] = {
 633         { .compatible = "fsl,mag3110" },
 634         { }
 635 };
 636 MODULE_DEVICE_TABLE(of, mag3110_of_match);
 637
 638 static struct i2c_driver mag3110_driver = {
 639         .driver = {
 640                 .name   = "mag3110",
 641                 .of_match_table = mag3110_of_match,
 642                 .pm     = pm_sleep_ptr(&mag3110_pm_ops),
 643         },
 644         .probe = mag3110_probe,
 645         .remove = mag3110_remove,
 646         .id_table = mag3110_id,
 647 };
 648 module_i2c_driver(mag3110_driver);
 649
 650 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
 651 MODULE_DESCRIPTION("Freescale MAG3110 magnetometer driver");
 652 MODULE_LICENSE("GPL");