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 75struct 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 95static const struct regmap_range rm3100_readable_ranges[] = { 96 regmap_reg_range(RM3100_R_REG_START, RM3100_R_REG_END), 97}; 98 99const struct regmap_access_table rm3100_readable_table = { 100 .yes_ranges = rm3100_readable_ranges, 101 .n_yes_ranges = ARRAY_SIZE(rm3100_readable_ranges), 102}; 103EXPORT_SYMBOL_NS_GPL(rm3100_readable_table, IIO_RM3100); 104 105static const struct regmap_range rm3100_writable_ranges[] = { 106 regmap_reg_range(RM3100_W_REG_START, RM3100_W_REG_END), 107}; 108 109const struct regmap_access_table rm3100_writable_table = { 110 .yes_ranges = rm3100_writable_ranges, 111 .n_yes_ranges = ARRAY_SIZE(rm3100_writable_ranges), 112}; 113EXPORT_SYMBOL_NS_GPL(rm3100_writable_table, IIO_RM3100); 114 115static const struct regmap_range rm3100_volatile_ranges[] = { 116 regmap_reg_range(RM3100_V_REG_START, RM3100_V_REG_END), 117}; 118 119const struct regmap_access_table rm3100_volatile_table = { 120 .yes_ranges = rm3100_volatile_ranges, 121 .n_yes_ranges = ARRAY_SIZE(rm3100_volatile_ranges), 122}; 123EXPORT_SYMBOL_NS_GPL(rm3100_volatile_table, IIO_RM3100); 124 125static 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 139static 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 if (!iio_buffer_enabled(indio_dev)) 145 complete(&data->measuring_done); 146 else 147 iio_trigger_poll(data->drdy_trig); 148 149 return IRQ_WAKE_THREAD; 150} 151 152static int rm3100_wait_measurement(struct rm3100_data *data) 153{ 154 struct regmap *regmap = data->regmap; 155 unsigned int val; 156 int tries = 20; 157 int ret; 158 159 /* 160 * A read cycle of 400kbits i2c bus is about 20us, plus the time 161 * used for scheduling, a read cycle of fast mode of this device 162 * can reach 1.7ms, it may be possible for data to arrive just 163 * after we check the RM3100_REG_STATUS. In this case, irq_handler is 164 * called before measuring_done is reinitialized, it will wait 165 * forever for data that has already been ready. 166 * Reinitialize measuring_done before looking up makes sure we 167 * will always capture interrupt no matter when it happens. 168 */ 169 if (data->use_interrupt) 170 reinit_completion(&data->measuring_done); 171 172 ret = regmap_read(regmap, RM3100_REG_STATUS, &val); 173 if (ret < 0) 174 return ret; 175 176 if ((val & RM3100_STATUS_DRDY) != RM3100_STATUS_DRDY) { 177 if (data->use_interrupt) { 178 ret = wait_for_completion_timeout(&data->measuring_done, 179 msecs_to_jiffies(data->conversion_time)); 180 if (!ret) 181 return -ETIMEDOUT; 182 } else { 183 do { 184 usleep_range(1000, 5000); 185 186 ret = regmap_read(regmap, RM3100_REG_STATUS, 187 &val); 188 if (ret < 0) 189 return ret; 190 191 if (val & RM3100_STATUS_DRDY) 192 break; 193 } while (--tries); 194 if (!tries) 195 return -ETIMEDOUT; 196 } 197 } 198 return 0; 199} 200 201static int rm3100_read_mag(struct rm3100_data *data, int idx, int *val) 202{ 203 struct regmap *regmap = data->regmap; 204 u8 buffer[3]; 205 int ret; 206 207 mutex_lock(&data->lock); 208 ret = regmap_write(regmap, RM3100_REG_POLL, BIT(4 + idx)); 209 if (ret < 0) 210 goto unlock_return; 211 212 ret = rm3100_wait_measurement(data); 213 if (ret < 0) 214 goto unlock_return; 215 216 ret = regmap_bulk_read(regmap, RM3100_REG_MX2 + 3 * idx, buffer, 3); 217 if (ret < 0) 218 goto unlock_return; 219 mutex_unlock(&data->lock); 220 221 *val = sign_extend32(get_unaligned_be24(&buffer[0]), 23); 222 223 return IIO_VAL_INT; 224 225unlock_return: 226 mutex_unlock(&data->lock); 227 return ret; 228} 229 230#define RM3100_CHANNEL(axis, idx) \ 231 { \ 232 .type = IIO_MAGN, \ 233 .modified = 1, \ 234 .channel2 = IIO_MOD_##axis, \ 235 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 236 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \ 237 BIT(IIO_CHAN_INFO_SAMP_FREQ), \ 238 .scan_index = idx, \ 239 .scan_type = { \ 240 .sign = 's', \ 241 .realbits = 24, \ 242 .storagebits = 32, \ 243 .shift = 8, \ 244 .endianness = IIO_BE, \ 245 }, \ 246 } 247 248static const struct iio_chan_spec rm3100_channels[] = { 249 RM3100_CHANNEL(X, 0), 250 RM3100_CHANNEL(Y, 1), 251 RM3100_CHANNEL(Z, 2), 252 IIO_CHAN_SOFT_TIMESTAMP(3), 253}; 254 255static IIO_CONST_ATTR_SAMP_FREQ_AVAIL( 256 "600 300 150 75 37 18 9 4.5 2.3 1.2 0.6 0.3 0.015 0.075" 257); 258 259static struct attribute *rm3100_attributes[] = { 260 &iio_const_attr_sampling_frequency_available.dev_attr.attr, 261 NULL, 262}; 263 264static const struct attribute_group rm3100_attribute_group = { 265 .attrs = rm3100_attributes, 266}; 267 268#define RM3100_SAMP_NUM 14 269 270/* 271 * Frequency : rm3100_samp_rates[][0].rm3100_samp_rates[][1]Hz. 272 * Time between reading: rm3100_sam_rates[][2]ms. 273 * The first one is actually 1.7ms. 274 */ 275static const int rm3100_samp_rates[RM3100_SAMP_NUM][3] = { 276 {600, 0, 2}, {300, 0, 3}, {150, 0, 7}, {75, 0, 13}, {37, 0, 27}, 277 {18, 0, 55}, {9, 0, 110}, {4, 500000, 220}, {2, 300000, 440}, 278 {1, 200000, 800}, {0, 600000, 1600}, {0, 300000, 3300}, 279 {0, 15000, 6700}, {0, 75000, 13000} 280}; 281 282static int rm3100_get_samp_freq(struct rm3100_data *data, int *val, int *val2) 283{ 284 unsigned int tmp; 285 int ret; 286 287 mutex_lock(&data->lock); 288 ret = regmap_read(data->regmap, RM3100_REG_TMRC, &tmp); 289 mutex_unlock(&data->lock); 290 if (ret < 0) 291 return ret; 292 *val = rm3100_samp_rates[tmp - RM3100_TMRC_OFFSET][0]; 293 *val2 = rm3100_samp_rates[tmp - RM3100_TMRC_OFFSET][1]; 294 295 return IIO_VAL_INT_PLUS_MICRO; 296} 297 298static int rm3100_set_cycle_count(struct rm3100_data *data, int val) 299{ 300 int ret; 301 u8 i; 302 303 for (i = 0; i < 3; i++) { 304 ret = regmap_write(data->regmap, RM3100_REG_CC_X + 2 * i, val); 305 if (ret < 0) 306 return ret; 307 } 308 309 /* 310 * The scale of this sensor depends on the cycle count value, these 311 * three values are corresponding to the cycle count value 50, 100, 312 * 200. scale = output / gain * 10^4. 313 */ 314 switch (val) { 315 case 50: 316 data->scale = 500; 317 break; 318 case 100: 319 data->scale = 263; 320 break; 321 /* 322 * case 200: 323 * This function will never be called by users' code, so here we 324 * assume that it will never get a wrong parameter. 325 */ 326 default: 327 data->scale = 133; 328 } 329 330 return 0; 331} 332 333static int rm3100_set_samp_freq(struct iio_dev *indio_dev, int val, int val2) 334{ 335 struct rm3100_data *data = iio_priv(indio_dev); 336 struct regmap *regmap = data->regmap; 337 unsigned int cycle_count; 338 int ret; 339 int i; 340 341 mutex_lock(&data->lock); 342 /* All cycle count registers use the same value. */ 343 ret = regmap_read(regmap, RM3100_REG_CC_X, &cycle_count); 344 if (ret < 0) 345 goto unlock_return; 346 347 for (i = 0; i < RM3100_SAMP_NUM; i++) { 348 if (val == rm3100_samp_rates[i][0] && 349 val2 == rm3100_samp_rates[i][1]) 350 break; 351 } 352 if (i == RM3100_SAMP_NUM) { 353 ret = -EINVAL; 354 goto unlock_return; 355 } 356 357 ret = regmap_write(regmap, RM3100_REG_TMRC, i + RM3100_TMRC_OFFSET); 358 if (ret < 0) 359 goto unlock_return; 360 361 /* Checking if cycle count registers need changing. */ 362 if (val == 600 && cycle_count == 200) { 363 ret = rm3100_set_cycle_count(data, 100); 364 if (ret < 0) 365 goto unlock_return; 366 } else if (val != 600 && cycle_count == 100) { 367 ret = rm3100_set_cycle_count(data, 200); 368 if (ret < 0) 369 goto unlock_return; 370 } 371 372 if (iio_buffer_enabled(indio_dev)) { 373 /* Writing TMRC registers requires CMM reset. */ 374 ret = regmap_write(regmap, RM3100_REG_CMM, 0); 375 if (ret < 0) 376 goto unlock_return; 377 ret = regmap_write(data->regmap, RM3100_REG_CMM, 378 (*indio_dev->active_scan_mask & 0x7) << 379 RM3100_CMM_AXIS_SHIFT | RM3100_CMM_START); 380 if (ret < 0) 381 goto unlock_return; 382 } 383 mutex_unlock(&data->lock); 384 385 data->conversion_time = rm3100_samp_rates[i][2] * 2; 386 return 0; 387 388unlock_return: 389 mutex_unlock(&data->lock); 390 return ret; 391} 392 393static int rm3100_read_raw(struct iio_dev *indio_dev, 394 const struct iio_chan_spec *chan, 395 int *val, int *val2, long mask) 396{ 397 struct rm3100_data *data = iio_priv(indio_dev); 398 int ret; 399 400 switch (mask) { 401 case IIO_CHAN_INFO_RAW: 402 ret = iio_device_claim_direct_mode(indio_dev); 403 if (ret < 0) 404 return ret; 405 406 ret = rm3100_read_mag(data, chan->scan_index, val); 407 iio_device_release_direct_mode(indio_dev); 408 409 return ret; 410 case IIO_CHAN_INFO_SCALE: 411 *val = 0; 412 *val2 = data->scale; 413 414 return IIO_VAL_INT_PLUS_MICRO; 415 case IIO_CHAN_INFO_SAMP_FREQ: 416 return rm3100_get_samp_freq(data, val, val2); 417 default: 418 return -EINVAL; 419 } 420} 421 422static int rm3100_write_raw(struct iio_dev *indio_dev, 423 struct iio_chan_spec const *chan, 424 int val, int val2, long mask) 425{ 426 switch (mask) { 427 case IIO_CHAN_INFO_SAMP_FREQ: 428 return rm3100_set_samp_freq(indio_dev, val, val2); 429 default: 430 return -EINVAL; 431 } 432} 433 434static const struct iio_info rm3100_info = { 435 .attrs = &rm3100_attribute_group, 436 .read_raw = rm3100_read_raw, 437 .write_raw = rm3100_write_raw, 438}; 439 440static int rm3100_buffer_preenable(struct iio_dev *indio_dev) 441{ 442 struct rm3100_data *data = iio_priv(indio_dev); 443 444 /* Starting channels enabled. */ 445 return regmap_write(data->regmap, RM3100_REG_CMM, 446 (*indio_dev->active_scan_mask & 0x7) << RM3100_CMM_AXIS_SHIFT | 447 RM3100_CMM_START); 448} 449 450static int rm3100_buffer_postdisable(struct iio_dev *indio_dev) 451{ 452 struct rm3100_data *data = iio_priv(indio_dev); 453 454 return regmap_write(data->regmap, RM3100_REG_CMM, 0); 455} 456 457static const struct iio_buffer_setup_ops rm3100_buffer_ops = { 458 .preenable = rm3100_buffer_preenable, 459 .postdisable = rm3100_buffer_postdisable, 460}; 461 462static irqreturn_t rm3100_trigger_handler(int irq, void *p) 463{ 464 struct iio_poll_func *pf = p; 465 struct iio_dev *indio_dev = pf->indio_dev; 466 unsigned long scan_mask = *indio_dev->active_scan_mask; 467 unsigned int mask_len = indio_dev->masklength; 468 struct rm3100_data *data = iio_priv(indio_dev); 469 struct regmap *regmap = data->regmap; 470 int ret, i, bit; 471 472 mutex_lock(&data->lock); 473 switch (scan_mask) { 474 case BIT(0) | BIT(1) | BIT(2): 475 ret = regmap_bulk_read(regmap, RM3100_REG_MX2, data->buffer, 9); 476 mutex_unlock(&data->lock); 477 if (ret < 0) 478 goto done; 479 /* Convert XXXYYYZZZxxx to XXXxYYYxZZZx. x for paddings. */ 480 for (i = 2; i > 0; i--) 481 memmove(data->buffer + i * 4, data->buffer + i * 3, 3); 482 break; 483 case BIT(0) | BIT(1): 484 ret = regmap_bulk_read(regmap, RM3100_REG_MX2, data->buffer, 6); 485 mutex_unlock(&data->lock); 486 if (ret < 0) 487 goto done; 488 memmove(data->buffer + 4, data->buffer + 3, 3); 489 break; 490 case BIT(1) | BIT(2): 491 ret = regmap_bulk_read(regmap, RM3100_REG_MY2, 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(0) | BIT(2): 498 ret = regmap_bulk_read(regmap, RM3100_REG_MX2, data->buffer, 9); 499 mutex_unlock(&data->lock); 500 if (ret < 0) 501 goto done; 502 memmove(data->buffer + 4, data->buffer + 6, 3); 503 break; 504 default: 505 for_each_set_bit(bit, &scan_mask, mask_len) { 506 ret = regmap_bulk_read(regmap, RM3100_REG_MX2 + 3 * bit, 507 data->buffer, 3); 508 if (ret < 0) { 509 mutex_unlock(&data->lock); 510 goto done; 511 } 512 } 513 mutex_unlock(&data->lock); 514 } 515 /* 516 * Always using the same buffer so that we wouldn't need to set the 517 * paddings to 0 in case of leaking any data. 518 */ 519 iio_push_to_buffers_with_timestamp(indio_dev, data->buffer, 520 pf->timestamp); 521done: 522 iio_trigger_notify_done(indio_dev->trig); 523 524 return IRQ_HANDLED; 525} 526 527int rm3100_common_probe(struct device *dev, struct regmap *regmap, int irq) 528{ 529 struct iio_dev *indio_dev; 530 struct rm3100_data *data; 531 unsigned int tmp; 532 int ret; 533 int samp_rate_index; 534 535 indio_dev = devm_iio_device_alloc(dev, sizeof(*data)); 536 if (!indio_dev) 537 return -ENOMEM; 538 539 data = iio_priv(indio_dev); 540 data->regmap = regmap; 541 542 mutex_init(&data->lock); 543 544 indio_dev->name = "rm3100"; 545 indio_dev->info = &rm3100_info; 546 indio_dev->channels = rm3100_channels; 547 indio_dev->num_channels = ARRAY_SIZE(rm3100_channels); 548 indio_dev->modes = INDIO_DIRECT_MODE; 549 550 if (!irq) 551 data->use_interrupt = false; 552 else { 553 data->use_interrupt = true; 554 555 init_completion(&data->measuring_done); 556 ret = devm_request_threaded_irq(dev, 557 irq, 558 rm3100_irq_handler, 559 rm3100_thread_fn, 560 IRQF_TRIGGER_HIGH | 561 IRQF_ONESHOT, 562 indio_dev->name, 563 indio_dev); 564 if (ret < 0) { 565 dev_err(dev, "request irq line failed.\n"); 566 return ret; 567 } 568 569 data->drdy_trig = devm_iio_trigger_alloc(dev, "%s-drdy%d", 570 indio_dev->name, 571 iio_device_id(indio_dev)); 572 if (!data->drdy_trig) 573 return -ENOMEM; 574 575 ret = devm_iio_trigger_register(dev, data->drdy_trig); 576 if (ret < 0) 577 return ret; 578 } 579 580 ret = devm_iio_triggered_buffer_setup(dev, indio_dev, 581 &iio_pollfunc_store_time, 582 rm3100_trigger_handler, 583 &rm3100_buffer_ops); 584 if (ret < 0) 585 return ret; 586 587 ret = regmap_read(regmap, RM3100_REG_TMRC, &tmp); 588 if (ret < 0) 589 return ret; 590 591 samp_rate_index = tmp - RM3100_TMRC_OFFSET; 592 if (samp_rate_index < 0 || samp_rate_index >= RM3100_SAMP_NUM) { 593 dev_err(dev, "The value read from RM3100_REG_TMRC is invalid!\n"); 594 return -EINVAL; 595 } 596 /* Initializing max wait time, which is double conversion time. */ 597 data->conversion_time = rm3100_samp_rates[samp_rate_index][2] * 2; 598 599 /* Cycle count values may not be what we want. */ 600 if ((tmp - RM3100_TMRC_OFFSET) == 0) 601 rm3100_set_cycle_count(data, 100); 602 else 603 rm3100_set_cycle_count(data, 200); 604 605 return devm_iio_device_register(dev, indio_dev); 606} 607EXPORT_SYMBOL_NS_GPL(rm3100_common_probe, IIO_RM3100); 608 609MODULE_AUTHOR("Song Qiang <songqiang1304521@gmail.com>"); 610MODULE_DESCRIPTION("PNI RM3100 3-axis magnetometer i2c driver"); 611MODULE_LICENSE("GPL v2"); 612