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 /* Ensure naturally aligned timestamp */ 82 u8 buffer[RM3100_SCAN_BYTES] __aligned(8); 83 struct iio_trigger *drdy_trig; 84 85 /* 86 * This lock is for protecting the consistency of series of i2c 87 * operations, that is, to make sure a measurement process will 88 * not be interrupted by a set frequency operation, which should 89 * be taken where a series of i2c operation starts, released where 90 * the operation ends. 91 */ 92 struct mutex lock; 93 }; 94 95 static const struct regmap_range rm3100_readable_ranges[] = { 96 regmap_reg_range(RM3100_R_REG_START, RM3100_R_REG_END), 97 }; 98 99 const struct regmap_access_table rm3100_readable_table = { 100 .yes_ranges = rm3100_readable_ranges, 101 .n_yes_ranges = ARRAY_SIZE(rm3100_readable_ranges), 102 }; 103 EXPORT_SYMBOL_GPL(rm3100_readable_table); 104 105 static const struct regmap_range rm3100_writable_ranges[] = { 106 regmap_reg_range(RM3100_W_REG_START, RM3100_W_REG_END), 107 }; 108 109 const struct regmap_access_table rm3100_writable_table = { 110 .yes_ranges = rm3100_writable_ranges, 111 .n_yes_ranges = ARRAY_SIZE(rm3100_writable_ranges), 112 }; 113 EXPORT_SYMBOL_GPL(rm3100_writable_table); 114 115 static const struct regmap_range rm3100_volatile_ranges[] = { 116 regmap_reg_range(RM3100_V_REG_START, RM3100_V_REG_END), 117 }; 118 119 const struct regmap_access_table rm3100_volatile_table = { 120 .yes_ranges = rm3100_volatile_ranges, 121 .n_yes_ranges = ARRAY_SIZE(rm3100_volatile_ranges), 122 }; 123 EXPORT_SYMBOL_GPL(rm3100_volatile_table); 124 125 static irqreturn_t rm3100_thread_fn(int irq, void *d) 126 { 127 struct iio_dev *indio_dev = d; 128 struct rm3100_data *data = iio_priv(indio_dev); 129 130 /* 131 * Write operation to any register or read operation 132 * to first byte of results will clear the interrupt. 133 */ 134 regmap_write(data->regmap, RM3100_REG_POLL, 0); 135 136 return IRQ_HANDLED; 137 } 138 139 static irqreturn_t rm3100_irq_handler(int irq, void *d) 140 { 141 struct iio_dev *indio_dev = d; 142 struct rm3100_data *data = iio_priv(indio_dev); 143 144 switch (indio_dev->currentmode) { 145 case INDIO_DIRECT_MODE: 146 complete(&data->measuring_done); 147 break; 148 case INDIO_BUFFER_TRIGGERED: 149 iio_trigger_poll(data->drdy_trig); 150 break; 151 default: 152 dev_err(indio_dev->dev.parent, 153 "device mode out of control, current mode: %d", 154 indio_dev->currentmode); 155 } 156 157 return IRQ_WAKE_THREAD; 158 } 159 160 static int rm3100_wait_measurement(struct rm3100_data *data) 161 { 162 struct regmap *regmap = data->regmap; 163 unsigned int val; 164 int tries = 20; 165 int ret; 166 167 /* 168 * A read cycle of 400kbits i2c bus is about 20us, plus the time 169 * used for scheduling, a read cycle of fast mode of this device 170 * can reach 1.7ms, it may be possible for data to arrive just 171 * after we check the RM3100_REG_STATUS. In this case, irq_handler is 172 * called before measuring_done is reinitialized, it will wait 173 * forever for data that has already been ready. 174 * Reinitialize measuring_done before looking up makes sure we 175 * will always capture interrupt no matter when it happens. 176 */ 177 if (data->use_interrupt) 178 reinit_completion(&data->measuring_done); 179 180 ret = regmap_read(regmap, RM3100_REG_STATUS, &val); 181 if (ret < 0) 182 return ret; 183 184 if ((val & RM3100_STATUS_DRDY) != RM3100_STATUS_DRDY) { 185 if (data->use_interrupt) { 186 ret = wait_for_completion_timeout(&data->measuring_done, 187 msecs_to_jiffies(data->conversion_time)); 188 if (!ret) 189 return -ETIMEDOUT; 190 } else { 191 do { 192 usleep_range(1000, 5000); 193 194 ret = regmap_read(regmap, RM3100_REG_STATUS, 195 &val); 196 if (ret < 0) 197 return ret; 198 199 if (val & RM3100_STATUS_DRDY) 200 break; 201 } while (--tries); 202 if (!tries) 203 return -ETIMEDOUT; 204 } 205 } 206 return 0; 207 } 208 209 static int rm3100_read_mag(struct rm3100_data *data, int idx, int *val) 210 { 211 struct regmap *regmap = data->regmap; 212 u8 buffer[3]; 213 int ret; 214 215 mutex_lock(&data->lock); 216 ret = regmap_write(regmap, RM3100_REG_POLL, BIT(4 + idx)); 217 if (ret < 0) 218 goto unlock_return; 219 220 ret = rm3100_wait_measurement(data); 221 if (ret < 0) 222 goto unlock_return; 223 224 ret = regmap_bulk_read(regmap, RM3100_REG_MX2 + 3 * idx, buffer, 3); 225 if (ret < 0) 226 goto unlock_return; 227 mutex_unlock(&data->lock); 228 229 *val = sign_extend32(get_unaligned_be24(&buffer[0]), 23); 230 231 return IIO_VAL_INT; 232 233 unlock_return: 234 mutex_unlock(&data->lock); 235 return ret; 236 } 237 238 #define RM3100_CHANNEL(axis, idx) \ 239 { \ 240 .type = IIO_MAGN, \ 241 .modified = 1, \ 242 .channel2 = IIO_MOD_##axis, \ 243 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 244 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \ 245 BIT(IIO_CHAN_INFO_SAMP_FREQ), \ 246 .scan_index = idx, \ 247 .scan_type = { \ 248 .sign = 's', \ 249 .realbits = 24, \ 250 .storagebits = 32, \ 251 .shift = 8, \ 252 .endianness = IIO_BE, \ 253 }, \ 254 } 255 256 static const struct iio_chan_spec rm3100_channels[] = { 257 RM3100_CHANNEL(X, 0), 258 RM3100_CHANNEL(Y, 1), 259 RM3100_CHANNEL(Z, 2), 260 IIO_CHAN_SOFT_TIMESTAMP(3), 261 }; 262 263 static IIO_CONST_ATTR_SAMP_FREQ_AVAIL( 264 "600 300 150 75 37 18 9 4.5 2.3 1.2 0.6 0.3 0.015 0.075" 265 ); 266 267 static struct attribute *rm3100_attributes[] = { 268 &iio_const_attr_sampling_frequency_available.dev_attr.attr, 269 NULL, 270 }; 271 272 static const struct attribute_group rm3100_attribute_group = { 273 .attrs = rm3100_attributes, 274 }; 275 276 #define RM3100_SAMP_NUM 14 277 278 /* 279 * Frequency : rm3100_samp_rates[][0].rm3100_samp_rates[][1]Hz. 280 * Time between reading: rm3100_sam_rates[][2]ms. 281 * The first one is actually 1.7ms. 282 */ 283 static const int rm3100_samp_rates[RM3100_SAMP_NUM][3] = { 284 {600, 0, 2}, {300, 0, 3}, {150, 0, 7}, {75, 0, 13}, {37, 0, 27}, 285 {18, 0, 55}, {9, 0, 110}, {4, 500000, 220}, {2, 300000, 440}, 286 {1, 200000, 800}, {0, 600000, 1600}, {0, 300000, 3300}, 287 {0, 15000, 6700}, {0, 75000, 13000} 288 }; 289 290 static int rm3100_get_samp_freq(struct rm3100_data *data, int *val, int *val2) 291 { 292 unsigned int tmp; 293 int ret; 294 295 mutex_lock(&data->lock); 296 ret = regmap_read(data->regmap, RM3100_REG_TMRC, &tmp); 297 mutex_unlock(&data->lock); 298 if (ret < 0) 299 return ret; 300 *val = rm3100_samp_rates[tmp - RM3100_TMRC_OFFSET][0]; 301 *val2 = rm3100_samp_rates[tmp - RM3100_TMRC_OFFSET][1]; 302 303 return IIO_VAL_INT_PLUS_MICRO; 304 } 305 306 static int rm3100_set_cycle_count(struct rm3100_data *data, int val) 307 { 308 int ret; 309 u8 i; 310 311 for (i = 0; i < 3; i++) { 312 ret = regmap_write(data->regmap, RM3100_REG_CC_X + 2 * i, val); 313 if (ret < 0) 314 return ret; 315 } 316 317 /* 318 * The scale of this sensor depends on the cycle count value, these 319 * three values are corresponding to the cycle count value 50, 100, 320 * 200. scale = output / gain * 10^4. 321 */ 322 switch (val) { 323 case 50: 324 data->scale = 500; 325 break; 326 case 100: 327 data->scale = 263; 328 break; 329 /* 330 * case 200: 331 * This function will never be called by users' code, so here we 332 * assume that it will never get a wrong parameter. 333 */ 334 default: 335 data->scale = 133; 336 } 337 338 return 0; 339 } 340 341 static int rm3100_set_samp_freq(struct iio_dev *indio_dev, int val, int val2) 342 { 343 struct rm3100_data *data = iio_priv(indio_dev); 344 struct regmap *regmap = data->regmap; 345 unsigned int cycle_count; 346 int ret; 347 int i; 348 349 mutex_lock(&data->lock); 350 /* All cycle count registers use the same value. */ 351 ret = regmap_read(regmap, RM3100_REG_CC_X, &cycle_count); 352 if (ret < 0) 353 goto unlock_return; 354 355 for (i = 0; i < RM3100_SAMP_NUM; i++) { 356 if (val == rm3100_samp_rates[i][0] && 357 val2 == rm3100_samp_rates[i][1]) 358 break; 359 } 360 if (i == RM3100_SAMP_NUM) { 361 ret = -EINVAL; 362 goto unlock_return; 363 } 364 365 ret = regmap_write(regmap, RM3100_REG_TMRC, i + RM3100_TMRC_OFFSET); 366 if (ret < 0) 367 goto unlock_return; 368 369 /* Checking if cycle count registers need changing. */ 370 if (val == 600 && cycle_count == 200) { 371 ret = rm3100_set_cycle_count(data, 100); 372 if (ret < 0) 373 goto unlock_return; 374 } else if (val != 600 && cycle_count == 100) { 375 ret = rm3100_set_cycle_count(data, 200); 376 if (ret < 0) 377 goto unlock_return; 378 } 379 380 if (indio_dev->currentmode == INDIO_BUFFER_TRIGGERED) { 381 /* Writing TMRC registers requires CMM reset. */ 382 ret = regmap_write(regmap, RM3100_REG_CMM, 0); 383 if (ret < 0) 384 goto unlock_return; 385 ret = regmap_write(data->regmap, RM3100_REG_CMM, 386 (*indio_dev->active_scan_mask & 0x7) << 387 RM3100_CMM_AXIS_SHIFT | RM3100_CMM_START); 388 if (ret < 0) 389 goto unlock_return; 390 } 391 mutex_unlock(&data->lock); 392 393 data->conversion_time = rm3100_samp_rates[i][2] * 2; 394 return 0; 395 396 unlock_return: 397 mutex_unlock(&data->lock); 398 return ret; 399 } 400 401 static int rm3100_read_raw(struct iio_dev *indio_dev, 402 const struct iio_chan_spec *chan, 403 int *val, int *val2, long mask) 404 { 405 struct rm3100_data *data = iio_priv(indio_dev); 406 int ret; 407 408 switch (mask) { 409 case IIO_CHAN_INFO_RAW: 410 ret = iio_device_claim_direct_mode(indio_dev); 411 if (ret < 0) 412 return ret; 413 414 ret = rm3100_read_mag(data, chan->scan_index, val); 415 iio_device_release_direct_mode(indio_dev); 416 417 return ret; 418 case IIO_CHAN_INFO_SCALE: 419 *val = 0; 420 *val2 = data->scale; 421 422 return IIO_VAL_INT_PLUS_MICRO; 423 case IIO_CHAN_INFO_SAMP_FREQ: 424 return rm3100_get_samp_freq(data, val, val2); 425 default: 426 return -EINVAL; 427 } 428 } 429 430 static int rm3100_write_raw(struct iio_dev *indio_dev, 431 struct iio_chan_spec const *chan, 432 int val, int val2, long mask) 433 { 434 switch (mask) { 435 case IIO_CHAN_INFO_SAMP_FREQ: 436 return rm3100_set_samp_freq(indio_dev, val, val2); 437 default: 438 return -EINVAL; 439 } 440 } 441 442 static const struct iio_info rm3100_info = { 443 .attrs = &rm3100_attribute_group, 444 .read_raw = rm3100_read_raw, 445 .write_raw = rm3100_write_raw, 446 }; 447 448 static int rm3100_buffer_preenable(struct iio_dev *indio_dev) 449 { 450 struct rm3100_data *data = iio_priv(indio_dev); 451 452 /* Starting channels enabled. */ 453 return regmap_write(data->regmap, RM3100_REG_CMM, 454 (*indio_dev->active_scan_mask & 0x7) << RM3100_CMM_AXIS_SHIFT | 455 RM3100_CMM_START); 456 } 457 458 static int rm3100_buffer_postdisable(struct iio_dev *indio_dev) 459 { 460 struct rm3100_data *data = iio_priv(indio_dev); 461 462 return regmap_write(data->regmap, RM3100_REG_CMM, 0); 463 } 464 465 static const struct iio_buffer_setup_ops rm3100_buffer_ops = { 466 .preenable = rm3100_buffer_preenable, 467 .postdisable = rm3100_buffer_postdisable, 468 }; 469 470 static irqreturn_t rm3100_trigger_handler(int irq, void *p) 471 { 472 struct iio_poll_func *pf = p; 473 struct iio_dev *indio_dev = pf->indio_dev; 474 unsigned long scan_mask = *indio_dev->active_scan_mask; 475 unsigned int mask_len = indio_dev->masklength; 476 struct rm3100_data *data = iio_priv(indio_dev); 477 struct regmap *regmap = data->regmap; 478 int ret, i, bit; 479 480 mutex_lock(&data->lock); 481 switch (scan_mask) { 482 case BIT(0) | BIT(1) | BIT(2): 483 ret = regmap_bulk_read(regmap, RM3100_REG_MX2, data->buffer, 9); 484 mutex_unlock(&data->lock); 485 if (ret < 0) 486 goto done; 487 /* Convert XXXYYYZZZxxx to XXXxYYYxZZZx. x for paddings. */ 488 for (i = 2; i > 0; i--) 489 memmove(data->buffer + i * 4, data->buffer + i * 3, 3); 490 break; 491 case BIT(0) | BIT(1): 492 ret = regmap_bulk_read(regmap, RM3100_REG_MX2, data->buffer, 6); 493 mutex_unlock(&data->lock); 494 if (ret < 0) 495 goto done; 496 memmove(data->buffer + 4, data->buffer + 3, 3); 497 break; 498 case BIT(1) | BIT(2): 499 ret = regmap_bulk_read(regmap, RM3100_REG_MY2, data->buffer, 6); 500 mutex_unlock(&data->lock); 501 if (ret < 0) 502 goto done; 503 memmove(data->buffer + 4, data->buffer + 3, 3); 504 break; 505 case BIT(0) | BIT(2): 506 ret = regmap_bulk_read(regmap, RM3100_REG_MX2, data->buffer, 9); 507 mutex_unlock(&data->lock); 508 if (ret < 0) 509 goto done; 510 memmove(data->buffer + 4, data->buffer + 6, 3); 511 break; 512 default: 513 for_each_set_bit(bit, &scan_mask, mask_len) { 514 ret = regmap_bulk_read(regmap, RM3100_REG_MX2 + 3 * bit, 515 data->buffer, 3); 516 if (ret < 0) { 517 mutex_unlock(&data->lock); 518 goto done; 519 } 520 } 521 mutex_unlock(&data->lock); 522 } 523 /* 524 * Always using the same buffer so that we wouldn't need to set the 525 * paddings to 0 in case of leaking any data. 526 */ 527 iio_push_to_buffers_with_timestamp(indio_dev, data->buffer, 528 pf->timestamp); 529 done: 530 iio_trigger_notify_done(indio_dev->trig); 531 532 return IRQ_HANDLED; 533 } 534 535 int rm3100_common_probe(struct device *dev, struct regmap *regmap, int irq) 536 { 537 struct iio_dev *indio_dev; 538 struct rm3100_data *data; 539 unsigned int tmp; 540 int ret; 541 542 indio_dev = devm_iio_device_alloc(dev, sizeof(*data)); 543 if (!indio_dev) 544 return -ENOMEM; 545 546 data = iio_priv(indio_dev); 547 data->regmap = regmap; 548 549 mutex_init(&data->lock); 550 551 indio_dev->name = "rm3100"; 552 indio_dev->info = &rm3100_info; 553 indio_dev->channels = rm3100_channels; 554 indio_dev->num_channels = ARRAY_SIZE(rm3100_channels); 555 indio_dev->modes = INDIO_DIRECT_MODE | INDIO_BUFFER_TRIGGERED; 556 indio_dev->currentmode = INDIO_DIRECT_MODE; 557 558 if (!irq) 559 data->use_interrupt = false; 560 else { 561 data->use_interrupt = true; 562 563 init_completion(&data->measuring_done); 564 ret = devm_request_threaded_irq(dev, 565 irq, 566 rm3100_irq_handler, 567 rm3100_thread_fn, 568 IRQF_TRIGGER_HIGH | 569 IRQF_ONESHOT, 570 indio_dev->name, 571 indio_dev); 572 if (ret < 0) { 573 dev_err(dev, "request irq line failed.\n"); 574 return ret; 575 } 576 577 data->drdy_trig = devm_iio_trigger_alloc(dev, "%s-drdy%d", 578 indio_dev->name, 579 iio_device_id(indio_dev)); 580 if (!data->drdy_trig) 581 return -ENOMEM; 582 583 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"); 615