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1// SPDX-License-Identifier: GPL-2.02/*3 * PNI RM3100 3-axis geomagnetic sensor driver core.4 *5 * Copyright (C) 2018 Song Qiang <songqiang1304521@gmail.com>6 *7 * User Manual available at8 * <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 <linux/unaligned.h>26 27#include "rm3100.h"28 29/* Cycle Count Registers. */30#define RM3100_REG_CC_X 0x0531#define RM3100_REG_CC_Y 0x0732#define RM3100_REG_CC_Z 0x0933 34/* Poll Measurement Mode register. */35#define RM3100_REG_POLL 0x0036#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 0x0142#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 0x0B49#define RM3100_TMRC_OFFSET 0x9250 51/* Result Status register. */52#define RM3100_REG_STATUS 0x3453#define RM3100_STATUS_DRDY BIT(7)54 55/* Measurement result registers. */56#define RM3100_REG_MX2 0x2457#define RM3100_REG_MY2 0x2758#define RM3100_REG_MZ2 0x2a59 60#define RM3100_W_REG_START RM3100_REG_POLL61#define RM3100_W_REG_END RM3100_REG_TMRC62#define RM3100_R_REG_START RM3100_REG_POLL63#define RM3100_R_REG_END RM3100_REG_STATUS64#define RM3100_V_REG_START RM3100_REG_POLL65#define RM3100_V_REG_END RM3100_REG_STATUS66 67/*68 * This is computed by hand, is the sum of channel storage bits and padding69 * bits, which is 4+4+4+12=24 in here.70 */71#define RM3100_SCAN_BYTES 2472 73#define RM3100_CMM_AXIS_SHIFT 474 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 i2c87 * operations, that is, to make sure a measurement process will88 * not be interrupted by a set frequency operation, which should89 * be taken where a series of i2c operation starts, released where90 * 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 operation132 * 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 else147 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 time161 * used for scheduling, a read cycle of fast mode of this device162 * can reach 1.7ms, it may be possible for data to arrive just163 * after we check the RM3100_REG_STATUS. In this case, irq_handler is164 * called before measuring_done is reinitialized, it will wait165 * forever for data that has already been ready.166 * Reinitialize measuring_done before looking up makes sure we167 * 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 14269 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, these311 * 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 we324 * 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 = iio_get_masklength(indio_dev);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 the517 * 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 else603 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