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"); 615