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 <linux/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_NS_GPL(rm3100_readable_table, IIO_RM3100);
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_NS_GPL(rm3100_writable_table, IIO_RM3100);
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_NS_GPL(rm3100_volatile_table, IIO_RM3100);
124
rm3100_thread_fn(int irq,void * d)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
rm3100_irq_handler(int irq,void * d)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 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
rm3100_wait_measurement(struct rm3100_data * data)152 static 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
rm3100_read_mag(struct rm3100_data * data,int idx,int * val)201 static 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
225 unlock_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
248 static 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
255 static 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
259 static struct attribute *rm3100_attributes[] = {
260 &iio_const_attr_sampling_frequency_available.dev_attr.attr,
261 NULL,
262 };
263
264 static 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 */
275 static 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
rm3100_get_samp_freq(struct rm3100_data * data,int * val,int * val2)282 static 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
rm3100_set_cycle_count(struct rm3100_data * data,int val)298 static 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
rm3100_set_samp_freq(struct iio_dev * indio_dev,int val,int val2)333 static 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
388 unlock_return:
389 mutex_unlock(&data->lock);
390 return ret;
391 }
392
rm3100_read_raw(struct iio_dev * indio_dev,const struct iio_chan_spec * chan,int * val,int * val2,long mask)393 static 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
rm3100_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)422 static 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
434 static 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
rm3100_buffer_preenable(struct iio_dev * indio_dev)440 static 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
rm3100_buffer_postdisable(struct iio_dev * indio_dev)450 static 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
457 static const struct iio_buffer_setup_ops rm3100_buffer_ops = {
458 .preenable = rm3100_buffer_preenable,
459 .postdisable = rm3100_buffer_postdisable,
460 };
461
rm3100_trigger_handler(int irq,void * p)462 static 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 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);
521 done:
522 iio_trigger_notify_done(indio_dev->trig);
523
524 return IRQ_HANDLED;
525 }
526
rm3100_common_probe(struct device * dev,struct regmap * regmap,int irq)527 int 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 }
607 EXPORT_SYMBOL_NS_GPL(rm3100_common_probe, IIO_RM3100);
608
609 MODULE_AUTHOR("Song Qiang <songqiang1304521@gmail.com>");
610 MODULE_DESCRIPTION("PNI RM3100 3-axis magnetometer i2c driver");
611 MODULE_LICENSE("GPL v2");
612