drivers/iio/magnetometer/mag3110.c

   1 /*
   2  * mag3110.c - Support for Freescale MAG3110 magnetometer sensor
   3  *
   4  * Copyright (c) 2013 Peter Meerwald <pmeerw@pmeerw.net>
   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  * (7-bit I2C slave address 0x0e)
  11  *
  12  * TODO: irq, user offset, oversampling, continuous mode
  13  */
  14
  15 #include <linux/module.h>
  16 #include <linux/i2c.h>
  17 #include <linux/iio/iio.h>
  18 #include <linux/iio/sysfs.h>
  19 #include <linux/iio/trigger_consumer.h>
  20 #include <linux/iio/buffer.h>
  21 #include <linux/iio/triggered_buffer.h>
  22 #include <linux/delay.h>
  23
  24 #define MAG3110_STATUS 0x00
  25 #define MAG3110_OUT_X 0x01 /* MSB first */
  26 #define MAG3110_OUT_Y 0x03
  27 #define MAG3110_OUT_Z 0x05
  28 #define MAG3110_WHO_AM_I 0x07
  29 #define MAG3110_SYSMOD 0x08
  30 #define MAG3110_OFF_X 0x09 /* MSB first */
  31 #define MAG3110_OFF_Y 0x0b
  32 #define MAG3110_OFF_Z 0x0d
  33 #define MAG3110_DIE_TEMP 0x0f
  34 #define MAG3110_CTRL_REG1 0x10
  35 #define MAG3110_CTRL_REG2 0x11
  36
  37 #define MAG3110_STATUS_DRDY (BIT(2) | BIT(1) | BIT(0))
  38
  39 #define MAG3110_CTRL_DR_MASK (BIT(7) | BIT(6) | BIT(5))
  40 #define MAG3110_CTRL_DR_SHIFT 5
  41 #define MAG3110_CTRL_DR_DEFAULT 0
  42
  43 #define MAG3110_SYSMOD_MODE_MASK GENMASK(1, 0)
  44
  45 #define MAG3110_CTRL_TM BIT(1) /* trigger single measurement */
  46 #define MAG3110_CTRL_AC BIT(0) /* continuous measurements */
  47
  48 #define MAG3110_CTRL_AUTO_MRST_EN BIT(7) /* magnetic auto-reset */
  49 #define MAG3110_CTRL_RAW BIT(5) /* measurements not user-offset corrected */
  50
  51 #define MAG3110_DEVICE_ID 0xc4
  52
  53 /* Each client has this additional data */
  54 struct mag3110_data {
  55         struct i2c_client *client;
  56         struct mutex lock;
  57         u8 ctrl_reg1;
  58         int sleep_val;
  59 };
  60
  61 static int mag3110_request(struct mag3110_data *data)
  62 {
  63         int ret, tries = 150;
  64
  65         if ((data->ctrl_reg1 & MAG3110_CTRL_AC) == 0) {
  66                 /* trigger measurement */
  67                 ret = i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
  68                         data->ctrl_reg1 | MAG3110_CTRL_TM);
  69                 if (ret < 0)
  70                         return ret;
  71         }
  72
  73         while (tries-- > 0) {
  74                 ret = i2c_smbus_read_byte_data(data->client, MAG3110_STATUS);
  75                 if (ret < 0)
  76                         return ret;
  77                 /* wait for data ready */
  78                 if ((ret & MAG3110_STATUS_DRDY) == MAG3110_STATUS_DRDY)
  79                         break;
  80
  81                 if (data->sleep_val <= 20)
  82                         usleep_range(data->sleep_val * 250, data->sleep_val * 500);
  83                 else
  84                         msleep(20);
  85         }
  86
  87         if (tries < 0) {
  88                 dev_err(&data->client->dev, "data not ready\n");
  89                 return -EIO;
  90         }
  91
  92         return 0;
  93 }
  94
  95 static int mag3110_read(struct mag3110_data *data, __be16 buf[3])
  96 {
  97         int ret;
  98
  99         mutex_lock(&data->lock);
 100         ret = mag3110_request(data);
 101         if (ret < 0) {
 102                 mutex_unlock(&data->lock);
 103                 return ret;
 104         }
 105         ret = i2c_smbus_read_i2c_block_data(data->client,
 106                 MAG3110_OUT_X, 3 * sizeof(__be16), (u8 *) buf);
 107         mutex_unlock(&data->lock);
 108
 109         return ret;
 110 }
 111
 112 static ssize_t mag3110_show_int_plus_micros(char *buf,
 113         const int (*vals)[2], int n)
 114 {
 115         size_t len = 0;
 116
 117         while (n-- > 0)
 118                 len += scnprintf(buf + len, PAGE_SIZE - len,
 119                         "%d.%06d ", vals[n][0], vals[n][1]);
 120
 121         /* replace trailing space by newline */
 122         buf[len - 1] = '\n';
 123
 124         return len;
 125 }
 126
 127 static int mag3110_get_int_plus_micros_index(const int (*vals)[2], int n,
 128                                         int val, int val2)
 129 {
 130         while (n-- > 0)
 131                 if (val == vals[n][0] && val2 == vals[n][1])
 132                         return n;
 133
 134         return -EINVAL;
 135 }
 136
 137 static const int mag3110_samp_freq[8][2] = {
 138         {80, 0}, {40, 0}, {20, 0}, {10, 0}, {5, 0}, {2, 500000},
 139         {1, 250000}, {0, 625000}
 140 };
 141
 142 static ssize_t mag3110_show_samp_freq_avail(struct device *dev,
 143                                 struct device_attribute *attr, char *buf)
 144 {
 145         return mag3110_show_int_plus_micros(buf, mag3110_samp_freq, 8);
 146 }
 147
 148 static IIO_DEV_ATTR_SAMP_FREQ_AVAIL(mag3110_show_samp_freq_avail);
 149
 150 static int mag3110_get_samp_freq_index(struct mag3110_data *data,
 151         int val, int val2)
 152 {
 153         return mag3110_get_int_plus_micros_index(mag3110_samp_freq, 8, val,
 154                 val2);
 155 }
 156
 157 static int mag3110_calculate_sleep(struct mag3110_data *data)
 158 {
 159         int ret, i = data->ctrl_reg1 >> MAG3110_CTRL_DR_SHIFT;
 160
 161         if (mag3110_samp_freq[i][0] > 0)
 162                 ret = 1000 / mag3110_samp_freq[i][0];
 163         else
 164                 ret = 1000;
 165
 166         return ret == 0 ? 1 : ret;
 167 }
 168
 169 static int mag3110_standby(struct mag3110_data *data)
 170 {
 171         return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
 172                 data->ctrl_reg1 & ~MAG3110_CTRL_AC);
 173 }
 174
 175 static int mag3110_wait_standby(struct mag3110_data *data)
 176 {
 177         int ret, tries = 30;
 178
 179         /*
 180          * Takes up to 1/ODR to come out of active mode into stby
 181          * Longest expected period is 12.5seconds.
 182          * We'll sleep for 500ms between checks
 183          */
 184         while (tries-- > 0) {
 185                 ret = i2c_smbus_read_byte_data(data->client, MAG3110_SYSMOD);
 186                 if (ret < 0) {
 187                         dev_err(&data->client->dev, "i2c error\n");
 188                         return ret;
 189                 }
 190                 /* wait for standby */
 191                 if ((ret & MAG3110_SYSMOD_MODE_MASK) == 0)
 192                         break;
 193
 194                 msleep_interruptible(500);
 195         }
 196
 197         if (tries < 0) {
 198                 dev_err(&data->client->dev, "device not entering standby mode\n");
 199                 return -EIO;
 200         }
 201
 202         return 0;
 203 }
 204
 205 static int mag3110_active(struct mag3110_data *data)
 206 {
 207         return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
 208                                          data->ctrl_reg1);
 209 }
 210
 211 /* returns >0 if active, 0 if in standby and <0 on error */
 212 static int mag3110_is_active(struct mag3110_data *data)
 213 {
 214         int reg;
 215
 216         reg = i2c_smbus_read_byte_data(data->client, MAG3110_CTRL_REG1);
 217         if (reg < 0)
 218                 return reg;
 219
 220         return reg & MAG3110_CTRL_AC;
 221 }
 222
 223 static int mag3110_change_config(struct mag3110_data *data, u8 reg, u8 val)
 224 {
 225         int ret;
 226         int is_active;
 227
 228         mutex_lock(&data->lock);
 229
 230         is_active = mag3110_is_active(data);
 231         if (is_active < 0) {
 232                 ret = is_active;
 233                 goto fail;
 234         }
 235
 236         /* config can only be changed when in standby */
 237         if (is_active > 0) {
 238                 ret = mag3110_standby(data);
 239                 if (ret < 0)
 240                         goto fail;
 241         }
 242
 243         /*
 244          * After coming out of active we must wait for the part
 245          * to transition to STBY. This can take up to 1 /ODR to occur
 246          */
 247         ret = mag3110_wait_standby(data);
 248         if (ret < 0)
 249                 goto fail;
 250
 251         ret = i2c_smbus_write_byte_data(data->client, reg, val);
 252         if (ret < 0)
 253                 goto fail;
 254
 255         if (is_active > 0) {
 256                 ret = mag3110_active(data);
 257                 if (ret < 0)
 258                         goto fail;
 259         }
 260
 261         ret = 0;
 262 fail:
 263         mutex_unlock(&data->lock);
 264
 265         return ret;
 266 }
 267
 268 static int mag3110_read_raw(struct iio_dev *indio_dev,
 269                             struct iio_chan_spec const *chan,
 270                             int *val, int *val2, long mask)
 271 {
 272         struct mag3110_data *data = iio_priv(indio_dev);
 273         __be16 buffer[3];
 274         int i, ret;
 275
 276         switch (mask) {
 277         case IIO_CHAN_INFO_RAW:
 278                 ret = iio_device_claim_direct_mode(indio_dev);
 279                 if (ret)
 280                         return ret;
 281
 282                 switch (chan->type) {
 283                 case IIO_MAGN: /* in 0.1 uT / LSB */
 284                         ret = mag3110_read(data, buffer);
 285                         if (ret < 0)
 286                                 goto release;
 287                         *val = sign_extend32(
 288                                 be16_to_cpu(buffer[chan->scan_index]), 15);
 289                         ret = IIO_VAL_INT;
 290                         break;
 291                 case IIO_TEMP: /* in 1 C / LSB */
 292                         mutex_lock(&data->lock);
 293                         ret = mag3110_request(data);
 294                         if (ret < 0) {
 295                                 mutex_unlock(&data->lock);
 296                                 goto release;
 297                         }
 298                         ret = i2c_smbus_read_byte_data(data->client,
 299                                 MAG3110_DIE_TEMP);
 300                         mutex_unlock(&data->lock);
 301                         if (ret < 0)
 302                                 goto release;
 303                         *val = sign_extend32(ret, 7);
 304                         ret = IIO_VAL_INT;
 305                         break;
 306                 default:
 307                         ret = -EINVAL;
 308                 }
 309 release:
 310                 iio_device_release_direct_mode(indio_dev);
 311                 return ret;
 312
 313         case IIO_CHAN_INFO_SCALE:
 314                 switch (chan->type) {
 315                 case IIO_MAGN:
 316                         *val = 0;
 317                         *val2 = 1000;
 318                         return IIO_VAL_INT_PLUS_MICRO;
 319                 case IIO_TEMP:
 320                         *val = 1000;
 321                         return IIO_VAL_INT;
 322                 default:
 323                         return -EINVAL;
 324                 }
 325         case IIO_CHAN_INFO_SAMP_FREQ:
 326                 i = data->ctrl_reg1 >> MAG3110_CTRL_DR_SHIFT;
 327                 *val = mag3110_samp_freq[i][0];
 328                 *val2 = mag3110_samp_freq[i][1];
 329                 return IIO_VAL_INT_PLUS_MICRO;
 330         case IIO_CHAN_INFO_CALIBBIAS:
 331                 ret = i2c_smbus_read_word_swapped(data->client,
 332                         MAG3110_OFF_X + 2 * chan->scan_index);
 333                 if (ret < 0)
 334                         return ret;
 335                 *val = sign_extend32(ret >> 1, 14);
 336                 return IIO_VAL_INT;
 337         }
 338         return -EINVAL;
 339 }
 340
 341 static int mag3110_write_raw(struct iio_dev *indio_dev,
 342                              struct iio_chan_spec const *chan,
 343                              int val, int val2, long mask)
 344 {
 345         struct mag3110_data *data = iio_priv(indio_dev);
 346         int rate, ret;
 347
 348         ret = iio_device_claim_direct_mode(indio_dev);
 349         if (ret)
 350                 return ret;
 351
 352         switch (mask) {
 353         case IIO_CHAN_INFO_SAMP_FREQ:
 354                 rate = mag3110_get_samp_freq_index(data, val, val2);
 355                 if (rate < 0) {
 356                         ret = -EINVAL;
 357                         break;
 358                 }
 359                 data->ctrl_reg1 &= 0xff & ~MAG3110_CTRL_DR_MASK
 360                                         & ~MAG3110_CTRL_AC;
 361                 data->ctrl_reg1 |= rate << MAG3110_CTRL_DR_SHIFT;
 362                 data->sleep_val = mag3110_calculate_sleep(data);
 363                 if (data->sleep_val < 40)
 364                         data->ctrl_reg1 |= MAG3110_CTRL_AC;
 365
 366                 ret = mag3110_change_config(data, MAG3110_CTRL_REG1,
 367                                             data->ctrl_reg1);
 368                 break;
 369         case IIO_CHAN_INFO_CALIBBIAS:
 370                 if (val < -10000 || val > 10000) {
 371                         ret = -EINVAL;
 372                         break;
 373                 }
 374                 ret = i2c_smbus_write_word_swapped(data->client,
 375                         MAG3110_OFF_X + 2 * chan->scan_index, val << 1);
 376                 break;
 377         default:
 378                 ret = -EINVAL;
 379                 break;
 380         }
 381         iio_device_release_direct_mode(indio_dev);
 382         return ret;
 383 }
 384
 385 static irqreturn_t mag3110_trigger_handler(int irq, void *p)
 386 {
 387         struct iio_poll_func *pf = p;
 388         struct iio_dev *indio_dev = pf->indio_dev;
 389         struct mag3110_data *data = iio_priv(indio_dev);
 390         u8 buffer[16]; /* 3 16-bit channels + 1 byte temp + padding + ts */
 391         int ret;
 392
 393         ret = mag3110_read(data, (__be16 *) buffer);
 394         if (ret < 0)
 395                 goto done;
 396
 397         if (test_bit(3, indio_dev->active_scan_mask)) {
 398                 ret = i2c_smbus_read_byte_data(data->client,
 399                         MAG3110_DIE_TEMP);
 400                 if (ret < 0)
 401                         goto done;
 402                 buffer[6] = ret;
 403         }
 404
 405         iio_push_to_buffers_with_timestamp(indio_dev, buffer,
 406                 iio_get_time_ns(indio_dev));
 407
 408 done:
 409         iio_trigger_notify_done(indio_dev->trig);
 410         return IRQ_HANDLED;
 411 }
 412
 413 #define MAG3110_CHANNEL(axis, idx) { \
 414         .type = IIO_MAGN, \
 415         .modified = 1, \
 416         .channel2 = IIO_MOD_##axis, \
 417         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
 418                 BIT(IIO_CHAN_INFO_CALIBBIAS), \
 419         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ) | \
 420                 BIT(IIO_CHAN_INFO_SCALE), \
 421         .scan_index = idx, \
 422         .scan_type = { \
 423                 .sign = 's', \
 424                 .realbits = 16, \
 425                 .storagebits = 16, \
 426                 .endianness = IIO_BE, \
 427         }, \
 428 }
 429
 430 static const struct iio_chan_spec mag3110_channels[] = {
 431         MAG3110_CHANNEL(X, 0),
 432         MAG3110_CHANNEL(Y, 1),
 433         MAG3110_CHANNEL(Z, 2),
 434         {
 435                 .type = IIO_TEMP,
 436                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 437                         BIT(IIO_CHAN_INFO_SCALE),
 438                 .scan_index = 3,
 439                 .scan_type = {
 440                         .sign = 's',
 441                         .realbits = 8,
 442                         .storagebits = 8,
 443                         },
 444         },
 445         IIO_CHAN_SOFT_TIMESTAMP(4),
 446 };
 447
 448 static struct attribute *mag3110_attributes[] = {
 449         &iio_dev_attr_sampling_frequency_available.dev_attr.attr,
 450         NULL
 451 };
 452
 453 static const struct attribute_group mag3110_group = {
 454         .attrs = mag3110_attributes,
 455 };
 456
 457 static const struct iio_info mag3110_info = {
 458         .attrs = &mag3110_group,
 459         .read_raw = &mag3110_read_raw,
 460         .write_raw = &mag3110_write_raw,
 461 };
 462
 463 static const unsigned long mag3110_scan_masks[] = {0x7, 0xf, 0};
 464
 465 static int mag3110_probe(struct i2c_client *client,
 466                          const struct i2c_device_id *id)
 467 {
 468         struct mag3110_data *data;
 469         struct iio_dev *indio_dev;
 470         int ret;
 471
 472         ret = i2c_smbus_read_byte_data(client, MAG3110_WHO_AM_I);
 473         if (ret < 0)
 474                 return ret;
 475         if (ret != MAG3110_DEVICE_ID)
 476                 return -ENODEV;
 477
 478         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 479         if (!indio_dev)
 480                 return -ENOMEM;
 481
 482         data = iio_priv(indio_dev);
 483         data->client = client;
 484         mutex_init(&data->lock);
 485
 486         i2c_set_clientdata(client, indio_dev);
 487         indio_dev->info = &mag3110_info;
 488         indio_dev->name = id->name;
 489         indio_dev->dev.parent = &client->dev;
 490         indio_dev->modes = INDIO_DIRECT_MODE;
 491         indio_dev->channels = mag3110_channels;
 492         indio_dev->num_channels = ARRAY_SIZE(mag3110_channels);
 493         indio_dev->available_scan_masks = mag3110_scan_masks;
 494
 495         data->ctrl_reg1 = MAG3110_CTRL_DR_DEFAULT << MAG3110_CTRL_DR_SHIFT;
 496         data->sleep_val = mag3110_calculate_sleep(data);
 497         if (data->sleep_val < 40)
 498                 data->ctrl_reg1 |= MAG3110_CTRL_AC;
 499
 500         ret = mag3110_change_config(data, MAG3110_CTRL_REG1, data->ctrl_reg1);
 501         if (ret < 0)
 502                 return ret;
 503
 504         ret = i2c_smbus_write_byte_data(client, MAG3110_CTRL_REG2,
 505                 MAG3110_CTRL_AUTO_MRST_EN);
 506         if (ret < 0)
 507                 goto standby_on_error;
 508
 509         ret = iio_triggered_buffer_setup(indio_dev, NULL,
 510                 mag3110_trigger_handler, NULL);
 511         if (ret < 0)
 512                 goto standby_on_error;
 513
 514         ret = iio_device_register(indio_dev);
 515         if (ret < 0)
 516                 goto buffer_cleanup;
 517         return 0;
 518
 519 buffer_cleanup:
 520         iio_triggered_buffer_cleanup(indio_dev);
 521 standby_on_error:
 522         mag3110_standby(iio_priv(indio_dev));
 523         return ret;
 524 }
 525
 526 static int mag3110_remove(struct i2c_client *client)
 527 {
 528         struct iio_dev *indio_dev = i2c_get_clientdata(client);
 529
 530         iio_device_unregister(indio_dev);
 531         iio_triggered_buffer_cleanup(indio_dev);
 532         mag3110_standby(iio_priv(indio_dev));
 533
 534         return 0;
 535 }
 536
 537 #ifdef CONFIG_PM_SLEEP
 538 static int mag3110_suspend(struct device *dev)
 539 {
 540         return mag3110_standby(iio_priv(i2c_get_clientdata(
 541                 to_i2c_client(dev))));
 542 }
 543
 544 static int mag3110_resume(struct device *dev)
 545 {
 546         struct mag3110_data *data = iio_priv(i2c_get_clientdata(
 547                 to_i2c_client(dev)));
 548
 549         return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
 550                 data->ctrl_reg1);
 551 }
 552
 553 static SIMPLE_DEV_PM_OPS(mag3110_pm_ops, mag3110_suspend, mag3110_resume);
 554 #define MAG3110_PM_OPS (&mag3110_pm_ops)
 555 #else
 556 #define MAG3110_PM_OPS NULL
 557 #endif
 558
 559 static const struct i2c_device_id mag3110_id[] = {
 560         { "mag3110", 0 },
 561         { }
 562 };
 563 MODULE_DEVICE_TABLE(i2c, mag3110_id);
 564
 565 static const struct of_device_id mag3110_of_match[] = {
 566         { .compatible = "fsl,mag3110" },
 567         { }
 568 };
 569 MODULE_DEVICE_TABLE(of, mag3110_of_match);
 570
 571 static struct i2c_driver mag3110_driver = {
 572         .driver = {
 573                 .name   = "mag3110",
 574                 .of_match_table = mag3110_of_match,
 575                 .pm     = MAG3110_PM_OPS,
 576         },
 577         .probe = mag3110_probe,
 578         .remove = mag3110_remove,
 579         .id_table = mag3110_id,
 580 };
 581 module_i2c_driver(mag3110_driver);
 582
 583 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
 584 MODULE_DESCRIPTION("Freescale MAG3110 magnetometer driver");
 585 MODULE_LICENSE("GPL");