drivers/iio/magnetometer/rm3100-core.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * PNI RM3100 3-axis geomagnetic sensor driver core.
   4  *
   5  * Copyright (C) 2018 Song Qiang <songqiang1304521@gmail.com>
   6  *
   7  * User Manual available at
   8  * <https://www.pnicorp.com/download/rm3100-user-manual/>
   9  *
  10  * TODO: event generation, pm.
  11  */
  12
  13 #include <linux/delay.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/module.h>
  16 #include <linux/slab.h>
  17
  18 #include <linux/iio/buffer.h>
  19 #include <linux/iio/iio.h>
  20 #include <linux/iio/sysfs.h>
  21 #include <linux/iio/trigger.h>
  22 #include <linux/iio/triggered_buffer.h>
  23 #include <linux/iio/trigger_consumer.h>
  24
  25 #include <asm/unaligned.h>
  26
  27 #include "rm3100.h"
  28
  29 /* Cycle Count Registers. */
  30 #define RM3100_REG_CC_X                 0x05
  31 #define RM3100_REG_CC_Y                 0x07
  32 #define RM3100_REG_CC_Z                 0x09
  33
  34 /* Poll Measurement Mode register. */
  35 #define RM3100_REG_POLL                 0x00
  36 #define         RM3100_POLL_X           BIT(4)
  37 #define         RM3100_POLL_Y           BIT(5)
  38 #define         RM3100_POLL_Z           BIT(6)
  39
  40 /* Continuous Measurement Mode register. */
  41 #define RM3100_REG_CMM                  0x01
  42 #define         RM3100_CMM_START        BIT(0)
  43 #define         RM3100_CMM_X            BIT(4)
  44 #define         RM3100_CMM_Y            BIT(5)
  45 #define         RM3100_CMM_Z            BIT(6)
  46
  47 /* TiMe Rate Configuration register. */
  48 #define RM3100_REG_TMRC                 0x0B
  49 #define RM3100_TMRC_OFFSET              0x92
  50
  51 /* Result Status register. */
  52 #define RM3100_REG_STATUS               0x34
  53 #define         RM3100_STATUS_DRDY      BIT(7)
  54
  55 /* Measurement result registers. */
  56 #define RM3100_REG_MX2                  0x24
  57 #define RM3100_REG_MY2                  0x27
  58 #define RM3100_REG_MZ2                  0x2a
  59
  60 #define RM3100_W_REG_START              RM3100_REG_POLL
  61 #define RM3100_W_REG_END                RM3100_REG_TMRC
  62 #define RM3100_R_REG_START              RM3100_REG_POLL
  63 #define RM3100_R_REG_END                RM3100_REG_STATUS
  64 #define RM3100_V_REG_START              RM3100_REG_POLL
  65 #define RM3100_V_REG_END                RM3100_REG_STATUS
  66
  67 /*
  68  * This is computed by hand, is the sum of channel storage bits and padding
  69  * bits, which is 4+4+4+12=24 in here.
  70  */
  71 #define RM3100_SCAN_BYTES               24
  72
  73 #define RM3100_CMM_AXIS_SHIFT           4
  74
  75 struct rm3100_data {
  76         struct regmap *regmap;
  77         struct completion measuring_done;
  78         bool use_interrupt;
  79         int conversion_time;
  80         int scale;
  81         u8 buffer[RM3100_SCAN_BYTES];
  82         struct iio_trigger *drdy_trig;
  83
  84         /*
  85          * This lock is for protecting the consistency of series of i2c
  86          * operations, that is, to make sure a measurement process will
  87          * not be interrupted by a set frequency operation, which should
  88          * be taken where a series of i2c operation starts, released where
  89          * the operation ends.
  90          */
  91         struct mutex lock;
  92 };
  93
  94 static const struct regmap_range rm3100_readable_ranges[] = {
  95         regmap_reg_range(RM3100_R_REG_START, RM3100_R_REG_END),
  96 };
  97
  98 const struct regmap_access_table rm3100_readable_table = {
  99         .yes_ranges = rm3100_readable_ranges,
 100         .n_yes_ranges = ARRAY_SIZE(rm3100_readable_ranges),
 101 };
 102 EXPORT_SYMBOL_GPL(rm3100_readable_table);
 103
 104 static const struct regmap_range rm3100_writable_ranges[] = {
 105         regmap_reg_range(RM3100_W_REG_START, RM3100_W_REG_END),
 106 };
 107
 108 const struct regmap_access_table rm3100_writable_table = {
 109         .yes_ranges = rm3100_writable_ranges,
 110         .n_yes_ranges = ARRAY_SIZE(rm3100_writable_ranges),
 111 };
 112 EXPORT_SYMBOL_GPL(rm3100_writable_table);
 113
 114 static const struct regmap_range rm3100_volatile_ranges[] = {
 115         regmap_reg_range(RM3100_V_REG_START, RM3100_V_REG_END),
 116 };
 117
 118 const struct regmap_access_table rm3100_volatile_table = {
 119         .yes_ranges = rm3100_volatile_ranges,
 120         .n_yes_ranges = ARRAY_SIZE(rm3100_volatile_ranges),
 121 };
 122 EXPORT_SYMBOL_GPL(rm3100_volatile_table);
 123
 124 static irqreturn_t rm3100_thread_fn(int irq, void *d)
 125 {
 126         struct iio_dev *indio_dev = d;
 127         struct rm3100_data *data = iio_priv(indio_dev);
 128
 129         /*
 130          * Write operation to any register or read operation
 131          * to first byte of results will clear the interrupt.
 132          */
 133         regmap_write(data->regmap, RM3100_REG_POLL, 0);
 134
 135         return IRQ_HANDLED;
 136 }
 137
 138 static irqreturn_t rm3100_irq_handler(int irq, void *d)
 139 {
 140         struct iio_dev *indio_dev = d;
 141         struct rm3100_data *data = iio_priv(indio_dev);
 142
 143         switch (indio_dev->currentmode) {
 144         case INDIO_DIRECT_MODE:
 145                 complete(&data->measuring_done);
 146                 break;
 147         case INDIO_BUFFER_TRIGGERED:
 148                 iio_trigger_poll(data->drdy_trig);
 149                 break;
 150         default:
 151                 dev_err(indio_dev->dev.parent,
 152                         "device mode out of control, current mode: %d",
 153                         indio_dev->currentmode);
 154         }
 155
 156         return IRQ_WAKE_THREAD;
 157 }
 158
 159 static int rm3100_wait_measurement(struct rm3100_data *data)
 160 {
 161         struct regmap *regmap = data->regmap;
 162         unsigned int val;
 163         int tries = 20;
 164         int ret;
 165
 166         /*
 167          * A read cycle of 400kbits i2c bus is about 20us, plus the time
 168          * used for scheduling, a read cycle of fast mode of this device
 169          * can reach 1.7ms, it may be possible for data to arrive just
 170          * after we check the RM3100_REG_STATUS. In this case, irq_handler is
 171          * called before measuring_done is reinitialized, it will wait
 172          * forever for data that has already been ready.
 173          * Reinitialize measuring_done before looking up makes sure we
 174          * will always capture interrupt no matter when it happens.
 175          */
 176         if (data->use_interrupt)
 177                 reinit_completion(&data->measuring_done);
 178
 179         ret = regmap_read(regmap, RM3100_REG_STATUS, &val);
 180         if (ret < 0)
 181                 return ret;
 182
 183         if ((val & RM3100_STATUS_DRDY) != RM3100_STATUS_DRDY) {
 184                 if (data->use_interrupt) {
 185                         ret = wait_for_completion_timeout(&data->measuring_done,
 186                                 msecs_to_jiffies(data->conversion_time));
 187                         if (!ret)
 188                                 return -ETIMEDOUT;
 189                 } else {
 190                         do {
 191                                 usleep_range(1000, 5000);
 192
 193                                 ret = regmap_read(regmap, RM3100_REG_STATUS,
 194                                                   &val);
 195                                 if (ret < 0)
 196                                         return ret;
 197
 198                                 if (val & RM3100_STATUS_DRDY)
 199                                         break;
 200                         } while (--tries);
 201                         if (!tries)
 202                                 return -ETIMEDOUT;
 203                 }
 204         }
 205         return 0;
 206 }
 207
 208 static int rm3100_read_mag(struct rm3100_data *data, int idx, int *val)
 209 {
 210         struct regmap *regmap = data->regmap;
 211         u8 buffer[3];
 212         int ret;
 213
 214         mutex_lock(&data->lock);
 215         ret = regmap_write(regmap, RM3100_REG_POLL, BIT(4 + idx));
 216         if (ret < 0)
 217                 goto unlock_return;
 218
 219         ret = rm3100_wait_measurement(data);
 220         if (ret < 0)
 221                 goto unlock_return;
 222
 223         ret = regmap_bulk_read(regmap, RM3100_REG_MX2 + 3 * idx, buffer, 3);
 224         if (ret < 0)
 225                 goto unlock_return;
 226         mutex_unlock(&data->lock);
 227
 228         *val = sign_extend32(get_unaligned_be24(&buffer[0]), 23);
 229
 230         return IIO_VAL_INT;
 231
 232 unlock_return:
 233         mutex_unlock(&data->lock);
 234         return ret;
 235 }
 236
 237 #define RM3100_CHANNEL(axis, idx)                                       \
 238         {                                                               \
 239                 .type = IIO_MAGN,                                       \
 240                 .modified = 1,                                          \
 241                 .channel2 = IIO_MOD_##axis,                             \
 242                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
 243                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) |  \
 244                         BIT(IIO_CHAN_INFO_SAMP_FREQ),                   \
 245                 .scan_index = idx,                                      \
 246                 .scan_type = {                                          \
 247                         .sign = 's',                                    \
 248                         .realbits = 24,                                 \
 249                         .storagebits = 32,                              \
 250                         .shift = 8,                                     \
 251                         .endianness = IIO_BE,                           \
 252                 },                                                      \
 253         }
 254
 255 static const struct iio_chan_spec rm3100_channels[] = {
 256         RM3100_CHANNEL(X, 0),
 257         RM3100_CHANNEL(Y, 1),
 258         RM3100_CHANNEL(Z, 2),
 259         IIO_CHAN_SOFT_TIMESTAMP(3),
 260 };
 261
 262 static IIO_CONST_ATTR_SAMP_FREQ_AVAIL(
 263         "600 300 150 75 37 18 9 4.5 2.3 1.2 0.6 0.3 0.015 0.075"
 264 );
 265
 266 static struct attribute *rm3100_attributes[] = {
 267         &iio_const_attr_sampling_frequency_available.dev_attr.attr,
 268         NULL,
 269 };
 270
 271 static const struct attribute_group rm3100_attribute_group = {
 272         .attrs = rm3100_attributes,
 273 };
 274
 275 #define RM3100_SAMP_NUM                 14
 276
 277 /*
 278  * Frequency : rm3100_samp_rates[][0].rm3100_samp_rates[][1]Hz.
 279  * Time between reading: rm3100_sam_rates[][2]ms.
 280  * The first one is actually 1.7ms.
 281  */
 282 static const int rm3100_samp_rates[RM3100_SAMP_NUM][3] = {
 283         {600, 0, 2}, {300, 0, 3}, {150, 0, 7}, {75, 0, 13}, {37, 0, 27},
 284         {18, 0, 55}, {9, 0, 110}, {4, 500000, 220}, {2, 300000, 440},
 285         {1, 200000, 800}, {0, 600000, 1600}, {0, 300000, 3300},
 286         {0, 15000, 6700},  {0, 75000, 13000}
 287 };
 288
 289 static int rm3100_get_samp_freq(struct rm3100_data *data, int *val, int *val2)
 290 {
 291         unsigned int tmp;
 292         int ret;
 293
 294         mutex_lock(&data->lock);
 295         ret = regmap_read(data->regmap, RM3100_REG_TMRC, &tmp);
 296         mutex_unlock(&data->lock);
 297         if (ret < 0)
 298                 return ret;
 299         *val = rm3100_samp_rates[tmp - RM3100_TMRC_OFFSET][0];
 300         *val2 = rm3100_samp_rates[tmp - RM3100_TMRC_OFFSET][1];
 301
 302         return IIO_VAL_INT_PLUS_MICRO;
 303 }
 304
 305 static int rm3100_set_cycle_count(struct rm3100_data *data, int val)
 306 {
 307         int ret;
 308         u8 i;
 309
 310         for (i = 0; i < 3; i++) {
 311                 ret = regmap_write(data->regmap, RM3100_REG_CC_X + 2 * i, val);
 312                 if (ret < 0)
 313                         return ret;
 314         }
 315
 316         /*
 317          * The scale of this sensor depends on the cycle count value, these
 318          * three values are corresponding to the cycle count value 50, 100,
 319          * 200. scale = output / gain * 10^4.
 320          */
 321         switch (val) {
 322         case 50:
 323                 data->scale = 500;
 324                 break;
 325         case 100:
 326                 data->scale = 263;
 327                 break;
 328         /*
 329          * case 200:
 330          * This function will never be called by users' code, so here we
 331          * assume that it will never get a wrong parameter.
 332          */
 333         default:
 334                 data->scale = 133;
 335         }
 336
 337         return 0;
 338 }
 339
 340 static int rm3100_set_samp_freq(struct iio_dev *indio_dev, int val, int val2)
 341 {
 342         struct rm3100_data *data = iio_priv(indio_dev);
 343         struct regmap *regmap = data->regmap;
 344         unsigned int cycle_count;
 345         int ret;
 346         int i;
 347
 348         mutex_lock(&data->lock);
 349         /* All cycle count registers use the same value. */
 350         ret = regmap_read(regmap, RM3100_REG_CC_X, &cycle_count);
 351         if (ret < 0)
 352                 goto unlock_return;
 353
 354         for (i = 0; i < RM3100_SAMP_NUM; i++) {
 355                 if (val == rm3100_samp_rates[i][0] &&
 356                     val2 == rm3100_samp_rates[i][1])
 357                         break;
 358         }
 359         if (i == RM3100_SAMP_NUM) {
 360                 ret = -EINVAL;
 361                 goto unlock_return;
 362         }
 363
 364         ret = regmap_write(regmap, RM3100_REG_TMRC, i + RM3100_TMRC_OFFSET);
 365         if (ret < 0)
 366                 goto unlock_return;
 367
 368         /* Checking if cycle count registers need changing. */
 369         if (val == 600 && cycle_count == 200) {
 370                 ret = rm3100_set_cycle_count(data, 100);
 371                 if (ret < 0)
 372                         goto unlock_return;
 373         } else if (val != 600 && cycle_count == 100) {
 374                 ret = rm3100_set_cycle_count(data, 200);
 375                 if (ret < 0)
 376                         goto unlock_return;
 377         }
 378
 379         if (indio_dev->currentmode == INDIO_BUFFER_TRIGGERED) {
 380                 /* Writing TMRC registers requires CMM reset. */
 381                 ret = regmap_write(regmap, RM3100_REG_CMM, 0);
 382                 if (ret < 0)
 383                         goto unlock_return;
 384                 ret = regmap_write(data->regmap, RM3100_REG_CMM,
 385                         (*indio_dev->active_scan_mask & 0x7) <<
 386                         RM3100_CMM_AXIS_SHIFT | RM3100_CMM_START);
 387                 if (ret < 0)
 388                         goto unlock_return;
 389         }
 390         mutex_unlock(&data->lock);
 391
 392         data->conversion_time = rm3100_samp_rates[i][2] * 2;
 393         return 0;
 394
 395 unlock_return:
 396         mutex_unlock(&data->lock);
 397         return ret;
 398 }
 399
 400 static int rm3100_read_raw(struct iio_dev *indio_dev,
 401                            const struct iio_chan_spec *chan,
 402                            int *val, int *val2, long mask)
 403 {
 404         struct rm3100_data *data = iio_priv(indio_dev);
 405         int ret;
 406
 407         switch (mask) {
 408         case IIO_CHAN_INFO_RAW:
 409                 ret = iio_device_claim_direct_mode(indio_dev);
 410                 if (ret < 0)
 411                         return ret;
 412
 413                 ret = rm3100_read_mag(data, chan->scan_index, val);
 414                 iio_device_release_direct_mode(indio_dev);
 415
 416                 return ret;
 417         case IIO_CHAN_INFO_SCALE:
 418                 *val = 0;
 419                 *val2 = data->scale;
 420
 421                 return IIO_VAL_INT_PLUS_MICRO;
 422         case IIO_CHAN_INFO_SAMP_FREQ:
 423                 return rm3100_get_samp_freq(data, val, val2);
 424         default:
 425                 return -EINVAL;
 426         }
 427 }
 428
 429 static int rm3100_write_raw(struct iio_dev *indio_dev,
 430                             struct iio_chan_spec const *chan,
 431                             int val, int val2, long mask)
 432 {
 433         switch (mask) {
 434         case IIO_CHAN_INFO_SAMP_FREQ:
 435                 return rm3100_set_samp_freq(indio_dev, val, val2);
 436         default:
 437                 return -EINVAL;
 438         }
 439 }
 440
 441 static const struct iio_info rm3100_info = {
 442         .attrs = &rm3100_attribute_group,
 443         .read_raw = rm3100_read_raw,
 444         .write_raw = rm3100_write_raw,
 445 };
 446
 447 static int rm3100_buffer_preenable(struct iio_dev *indio_dev)
 448 {
 449         struct rm3100_data *data = iio_priv(indio_dev);
 450
 451         /* Starting channels enabled. */
 452         return regmap_write(data->regmap, RM3100_REG_CMM,
 453                 (*indio_dev->active_scan_mask & 0x7) << RM3100_CMM_AXIS_SHIFT |
 454                 RM3100_CMM_START);
 455 }
 456
 457 static int rm3100_buffer_postdisable(struct iio_dev *indio_dev)
 458 {
 459         struct rm3100_data *data = iio_priv(indio_dev);
 460
 461         return regmap_write(data->regmap, RM3100_REG_CMM, 0);
 462 }
 463
 464 static const struct iio_buffer_setup_ops rm3100_buffer_ops = {
 465         .preenable = rm3100_buffer_preenable,
 466         .postdisable = rm3100_buffer_postdisable,
 467 };
 468
 469 static irqreturn_t rm3100_trigger_handler(int irq, void *p)
 470 {
 471         struct iio_poll_func *pf = p;
 472         struct iio_dev *indio_dev = pf->indio_dev;
 473         unsigned long scan_mask = *indio_dev->active_scan_mask;
 474         unsigned int mask_len = indio_dev->masklength;
 475         struct rm3100_data *data = iio_priv(indio_dev);
 476         struct regmap *regmap = data->regmap;
 477         int ret, i, bit;
 478
 479         mutex_lock(&data->lock);
 480         switch (scan_mask) {
 481         case BIT(0) | BIT(1) | BIT(2):
 482                 ret = regmap_bulk_read(regmap, RM3100_REG_MX2, data->buffer, 9);
 483                 mutex_unlock(&data->lock);
 484                 if (ret < 0)
 485                         goto done;
 486                 /* Convert XXXYYYZZZxxx to XXXxYYYxZZZx. x for paddings. */
 487                 for (i = 2; i > 0; i--)
 488                         memmove(data->buffer + i * 4, data->buffer + i * 3, 3);
 489                 break;
 490         case BIT(0) | BIT(1):
 491                 ret = regmap_bulk_read(regmap, RM3100_REG_MX2, data->buffer, 6);
 492                 mutex_unlock(&data->lock);
 493                 if (ret < 0)
 494                         goto done;
 495                 memmove(data->buffer + 4, data->buffer + 3, 3);
 496                 break;
 497         case BIT(1) | BIT(2):
 498                 ret = regmap_bulk_read(regmap, RM3100_REG_MY2, data->buffer, 6);
 499                 mutex_unlock(&data->lock);
 500                 if (ret < 0)
 501                         goto done;
 502                 memmove(data->buffer + 4, data->buffer + 3, 3);
 503                 break;
 504         case BIT(0) | BIT(2):
 505                 ret = regmap_bulk_read(regmap, RM3100_REG_MX2, data->buffer, 9);
 506                 mutex_unlock(&data->lock);
 507                 if (ret < 0)
 508                         goto done;
 509                 memmove(data->buffer + 4, data->buffer + 6, 3);
 510                 break;
 511         default:
 512                 for_each_set_bit(bit, &scan_mask, mask_len) {
 513                         ret = regmap_bulk_read(regmap, RM3100_REG_MX2 + 3 * bit,
 514                                                data->buffer, 3);
 515                         if (ret < 0) {
 516                                 mutex_unlock(&data->lock);
 517                                 goto done;
 518                         }
 519                 }
 520                 mutex_unlock(&data->lock);
 521         }
 522         /*
 523          * Always using the same buffer so that we wouldn't need to set the
 524          * paddings to 0 in case of leaking any data.
 525          */
 526         iio_push_to_buffers_with_timestamp(indio_dev, data->buffer,
 527                                            pf->timestamp);
 528 done:
 529         iio_trigger_notify_done(indio_dev->trig);
 530
 531         return IRQ_HANDLED;
 532 }
 533
 534 int rm3100_common_probe(struct device *dev, struct regmap *regmap, int irq)
 535 {
 536         struct iio_dev *indio_dev;
 537         struct rm3100_data *data;
 538         unsigned int tmp;
 539         int ret;
 540
 541         indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
 542         if (!indio_dev)
 543                 return -ENOMEM;
 544
 545         data = iio_priv(indio_dev);
 546         data->regmap = regmap;
 547
 548         mutex_init(&data->lock);
 549
 550         indio_dev->name = "rm3100";
 551         indio_dev->info = &rm3100_info;
 552         indio_dev->channels = rm3100_channels;
 553         indio_dev->num_channels = ARRAY_SIZE(rm3100_channels);
 554         indio_dev->modes = INDIO_DIRECT_MODE | INDIO_BUFFER_TRIGGERED;
 555         indio_dev->currentmode = INDIO_DIRECT_MODE;
 556
 557         if (!irq)
 558                 data->use_interrupt = false;
 559         else {
 560                 data->use_interrupt = true;
 561
 562                 init_completion(&data->measuring_done);
 563                 ret = devm_request_threaded_irq(dev,
 564                                                 irq,
 565                                                 rm3100_irq_handler,
 566                                                 rm3100_thread_fn,
 567                                                 IRQF_TRIGGER_HIGH |
 568                                                 IRQF_ONESHOT,
 569                                                 indio_dev->name,
 570                                                 indio_dev);
 571                 if (ret < 0) {
 572                         dev_err(dev, "request irq line failed.\n");
 573                         return ret;
 574                 }
 575
 576                 data->drdy_trig = devm_iio_trigger_alloc(dev, "%s-drdy%d",
 577                                                          indio_dev->name,
 578                                                          indio_dev->id);
 579                 if (!data->drdy_trig)
 580                         return -ENOMEM;
 581
 582                 data->drdy_trig->dev.parent = dev;
 583                 ret = devm_iio_trigger_register(dev, data->drdy_trig);
 584                 if (ret < 0)
 585                         return ret;
 586         }
 587
 588         ret = devm_iio_triggered_buffer_setup(dev, indio_dev,
 589                                               &iio_pollfunc_store_time,
 590                                               rm3100_trigger_handler,
 591                                               &rm3100_buffer_ops);
 592         if (ret < 0)
 593                 return ret;
 594
 595         ret = regmap_read(regmap, RM3100_REG_TMRC, &tmp);
 596         if (ret < 0)
 597                 return ret;
 598         /* Initializing max wait time, which is double conversion time. */
 599         data->conversion_time = rm3100_samp_rates[tmp - RM3100_TMRC_OFFSET][2]
 600                                 * 2;
 601
 602         /* Cycle count values may not be what we want. */
 603         if ((tmp - RM3100_TMRC_OFFSET) == 0)
 604                 rm3100_set_cycle_count(data, 100);
 605         else
 606                 rm3100_set_cycle_count(data, 200);
 607
 608         return devm_iio_device_register(dev, indio_dev);
 609 }
 610 EXPORT_SYMBOL_GPL(rm3100_common_probe);
 611
 612 MODULE_AUTHOR("Song Qiang <songqiang1304521@gmail.com>");
 613 MODULE_DESCRIPTION("PNI RM3100 3-axis magnetometer i2c driver");
 614 MODULE_LICENSE("GPL v2");