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 "rm3100.h"
26
27 /* Cycle Count Registers. */
28 #define RM3100_REG_CC_X 0x05
29 #define RM3100_REG_CC_Y 0x07
30 #define RM3100_REG_CC_Z 0x09
31
32 /* Poll Measurement Mode register. */
33 #define RM3100_REG_POLL 0x00
34 #define RM3100_POLL_X BIT(4)
35 #define RM3100_POLL_Y BIT(5)
36 #define RM3100_POLL_Z BIT(6)
37
38 /* Continuous Measurement Mode register. */
39 #define RM3100_REG_CMM 0x01
40 #define RM3100_CMM_START BIT(0)
41 #define RM3100_CMM_X BIT(4)
42 #define RM3100_CMM_Y BIT(5)
43 #define RM3100_CMM_Z BIT(6)
44
45 /* TiMe Rate Configuration register. */
46 #define RM3100_REG_TMRC 0x0B
47 #define RM3100_TMRC_OFFSET 0x92
48
49 /* Result Status register. */
50 #define RM3100_REG_STATUS 0x34
51 #define RM3100_STATUS_DRDY BIT(7)
52
53 /* Measurement result registers. */
54 #define RM3100_REG_MX2 0x24
55 #define RM3100_REG_MY2 0x27
56 #define RM3100_REG_MZ2 0x2a
57
58 #define RM3100_W_REG_START RM3100_REG_POLL
59 #define RM3100_W_REG_END RM3100_REG_TMRC
60 #define RM3100_R_REG_START RM3100_REG_POLL
61 #define RM3100_R_REG_END RM3100_REG_STATUS
62 #define RM3100_V_REG_START RM3100_REG_POLL
63 #define RM3100_V_REG_END RM3100_REG_STATUS
64
65 /*
66 * This is computed by hand, is the sum of channel storage bits and padding
67 * bits, which is 4+4+4+12=24 in here.
68 */
69 #define RM3100_SCAN_BYTES 24
70
71 #define RM3100_CMM_AXIS_SHIFT 4
72
73 struct rm3100_data {
74 struct regmap *regmap;
75 struct completion measuring_done;
76 bool use_interrupt;
77 int conversion_time;
78 int scale;
79 /* Ensure naturally aligned timestamp */
80 u8 buffer[RM3100_SCAN_BYTES] __aligned(8);
81 struct iio_trigger *drdy_trig;
82
83 /*
84 * This lock is for protecting the consistency of series of i2c
85 * operations, that is, to make sure a measurement process will
86 * not be interrupted by a set frequency operation, which should
87 * be taken where a series of i2c operation starts, released where
88 * the operation ends.
89 */
90 struct mutex lock;
91 };
92
93 static const struct regmap_range rm3100_readable_ranges[] = {
94 regmap_reg_range(RM3100_R_REG_START, RM3100_R_REG_END),
95 };
96
97 const struct regmap_access_table rm3100_readable_table = {
98 .yes_ranges = rm3100_readable_ranges,
99 .n_yes_ranges = ARRAY_SIZE(rm3100_readable_ranges),
100 };
101 EXPORT_SYMBOL_GPL(rm3100_readable_table);
102
103 static const struct regmap_range rm3100_writable_ranges[] = {
104 regmap_reg_range(RM3100_W_REG_START, RM3100_W_REG_END),
105 };
106
107 const struct regmap_access_table rm3100_writable_table = {
108 .yes_ranges = rm3100_writable_ranges,
109 .n_yes_ranges = ARRAY_SIZE(rm3100_writable_ranges),
110 };
111 EXPORT_SYMBOL_GPL(rm3100_writable_table);
112
113 static const struct regmap_range rm3100_volatile_ranges[] = {
114 regmap_reg_range(RM3100_V_REG_START, RM3100_V_REG_END),
115 };
116
117 const struct regmap_access_table rm3100_volatile_table = {
118 .yes_ranges = rm3100_volatile_ranges,
119 .n_yes_ranges = ARRAY_SIZE(rm3100_volatile_ranges),
120 };
121 EXPORT_SYMBOL_GPL(rm3100_volatile_table);
122
rm3100_thread_fn(int irq,void * d)123 static irqreturn_t rm3100_thread_fn(int irq, void *d)
124 {
125 struct iio_dev *indio_dev = d;
126 struct rm3100_data *data = iio_priv(indio_dev);
127
128 /*
129 * Write operation to any register or read operation
130 * to first byte of results will clear the interrupt.
131 */
132 regmap_write(data->regmap, RM3100_REG_POLL, 0);
133
134 return IRQ_HANDLED;
135 }
136
rm3100_irq_handler(int irq,void * d)137 static irqreturn_t rm3100_irq_handler(int irq, void *d)
138 {
139 struct iio_dev *indio_dev = d;
140 struct rm3100_data *data = iio_priv(indio_dev);
141
142 switch (indio_dev->currentmode) {
143 case INDIO_DIRECT_MODE:
144 complete(&data->measuring_done);
145 break;
146 case INDIO_BUFFER_TRIGGERED:
147 iio_trigger_poll(data->drdy_trig);
148 break;
149 default:
150 dev_err(indio_dev->dev.parent,
151 "device mode out of control, current mode: %d",
152 indio_dev->currentmode);
153 }
154
155 return IRQ_WAKE_THREAD;
156 }
157
rm3100_wait_measurement(struct rm3100_data * data)158 static int rm3100_wait_measurement(struct rm3100_data *data)
159 {
160 struct regmap *regmap = data->regmap;
161 unsigned int val;
162 int tries = 20;
163 int ret;
164
165 /*
166 * A read cycle of 400kbits i2c bus is about 20us, plus the time
167 * used for scheduling, a read cycle of fast mode of this device
168 * can reach 1.7ms, it may be possible for data to arrive just
169 * after we check the RM3100_REG_STATUS. In this case, irq_handler is
170 * called before measuring_done is reinitialized, it will wait
171 * forever for data that has already been ready.
172 * Reinitialize measuring_done before looking up makes sure we
173 * will always capture interrupt no matter when it happens.
174 */
175 if (data->use_interrupt)
176 reinit_completion(&data->measuring_done);
177
178 ret = regmap_read(regmap, RM3100_REG_STATUS, &val);
179 if (ret < 0)
180 return ret;
181
182 if ((val & RM3100_STATUS_DRDY) != RM3100_STATUS_DRDY) {
183 if (data->use_interrupt) {
184 ret = wait_for_completion_timeout(&data->measuring_done,
185 msecs_to_jiffies(data->conversion_time));
186 if (!ret)
187 return -ETIMEDOUT;
188 } else {
189 do {
190 usleep_range(1000, 5000);
191
192 ret = regmap_read(regmap, RM3100_REG_STATUS,
193 &val);
194 if (ret < 0)
195 return ret;
196
197 if (val & RM3100_STATUS_DRDY)
198 break;
199 } while (--tries);
200 if (!tries)
201 return -ETIMEDOUT;
202 }
203 }
204 return 0;
205 }
206
rm3100_read_mag(struct rm3100_data * data,int idx,int * val)207 static int rm3100_read_mag(struct rm3100_data *data, int idx, int *val)
208 {
209 struct regmap *regmap = data->regmap;
210 u8 buffer[3];
211 int ret;
212
213 mutex_lock(&data->lock);
214 ret = regmap_write(regmap, RM3100_REG_POLL, BIT(4 + idx));
215 if (ret < 0)
216 goto unlock_return;
217
218 ret = rm3100_wait_measurement(data);
219 if (ret < 0)
220 goto unlock_return;
221
222 ret = regmap_bulk_read(regmap, RM3100_REG_MX2 + 3 * idx, buffer, 3);
223 if (ret < 0)
224 goto unlock_return;
225 mutex_unlock(&data->lock);
226
227 *val = sign_extend32((buffer[0] << 16) | (buffer[1] << 8) | buffer[2],
228 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
rm3100_get_samp_freq(struct rm3100_data * data,int * val,int * val2)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
rm3100_set_cycle_count(struct rm3100_data * data,int val)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
rm3100_set_samp_freq(struct iio_dev * indio_dev,int val,int val2)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
rm3100_read_raw(struct iio_dev * indio_dev,const struct iio_chan_spec * chan,int * val,int * val2,long mask)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
rm3100_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)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
rm3100_buffer_preenable(struct iio_dev * indio_dev)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
rm3100_buffer_postdisable(struct iio_dev * indio_dev)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 .postenable = iio_triggered_buffer_postenable,
467 .predisable = iio_triggered_buffer_predisable,
468 .postdisable = rm3100_buffer_postdisable,
469 };
470
rm3100_trigger_handler(int irq,void * p)471 static irqreturn_t rm3100_trigger_handler(int irq, void *p)
472 {
473 struct iio_poll_func *pf = p;
474 struct iio_dev *indio_dev = pf->indio_dev;
475 unsigned long scan_mask = *indio_dev->active_scan_mask;
476 unsigned int mask_len = indio_dev->masklength;
477 struct rm3100_data *data = iio_priv(indio_dev);
478 struct regmap *regmap = data->regmap;
479 int ret, i, bit;
480
481 mutex_lock(&data->lock);
482 switch (scan_mask) {
483 case BIT(0) | BIT(1) | BIT(2):
484 ret = regmap_bulk_read(regmap, RM3100_REG_MX2, data->buffer, 9);
485 mutex_unlock(&data->lock);
486 if (ret < 0)
487 goto done;
488 /* Convert XXXYYYZZZxxx to XXXxYYYxZZZx. x for paddings. */
489 for (i = 2; i > 0; i--)
490 memmove(data->buffer + i * 4, data->buffer + i * 3, 3);
491 break;
492 case BIT(0) | BIT(1):
493 ret = regmap_bulk_read(regmap, RM3100_REG_MX2, data->buffer, 6);
494 mutex_unlock(&data->lock);
495 if (ret < 0)
496 goto done;
497 memmove(data->buffer + 4, data->buffer + 3, 3);
498 break;
499 case BIT(1) | BIT(2):
500 ret = regmap_bulk_read(regmap, RM3100_REG_MY2, data->buffer, 6);
501 mutex_unlock(&data->lock);
502 if (ret < 0)
503 goto done;
504 memmove(data->buffer + 4, data->buffer + 3, 3);
505 break;
506 case BIT(0) | BIT(2):
507 ret = regmap_bulk_read(regmap, RM3100_REG_MX2, data->buffer, 9);
508 mutex_unlock(&data->lock);
509 if (ret < 0)
510 goto done;
511 memmove(data->buffer + 4, data->buffer + 6, 3);
512 break;
513 default:
514 for_each_set_bit(bit, &scan_mask, mask_len) {
515 ret = regmap_bulk_read(regmap, RM3100_REG_MX2 + 3 * bit,
516 data->buffer, 3);
517 if (ret < 0) {
518 mutex_unlock(&data->lock);
519 goto done;
520 }
521 }
522 mutex_unlock(&data->lock);
523 }
524 /*
525 * Always using the same buffer so that we wouldn't need to set the
526 * paddings to 0 in case of leaking any data.
527 */
528 iio_push_to_buffers_with_timestamp(indio_dev, data->buffer,
529 pf->timestamp);
530 done:
531 iio_trigger_notify_done(indio_dev->trig);
532
533 return IRQ_HANDLED;
534 }
535
rm3100_common_probe(struct device * dev,struct regmap * regmap,int irq)536 int rm3100_common_probe(struct device *dev, struct regmap *regmap, int irq)
537 {
538 struct iio_dev *indio_dev;
539 struct rm3100_data *data;
540 unsigned int tmp;
541 int ret;
542 int samp_rate_index;
543
544 indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
545 if (!indio_dev)
546 return -ENOMEM;
547
548 data = iio_priv(indio_dev);
549 data->regmap = regmap;
550
551 mutex_init(&data->lock);
552
553 indio_dev->dev.parent = dev;
554 indio_dev->name = "rm3100";
555 indio_dev->info = &rm3100_info;
556 indio_dev->channels = rm3100_channels;
557 indio_dev->num_channels = ARRAY_SIZE(rm3100_channels);
558 indio_dev->modes = INDIO_DIRECT_MODE | INDIO_BUFFER_TRIGGERED;
559 indio_dev->currentmode = INDIO_DIRECT_MODE;
560
561 if (!irq)
562 data->use_interrupt = false;
563 else {
564 data->use_interrupt = true;
565
566 init_completion(&data->measuring_done);
567 ret = devm_request_threaded_irq(dev,
568 irq,
569 rm3100_irq_handler,
570 rm3100_thread_fn,
571 IRQF_TRIGGER_HIGH |
572 IRQF_ONESHOT,
573 indio_dev->name,
574 indio_dev);
575 if (ret < 0) {
576 dev_err(dev, "request irq line failed.\n");
577 return ret;
578 }
579
580 data->drdy_trig = devm_iio_trigger_alloc(dev, "%s-drdy%d",
581 indio_dev->name,
582 indio_dev->id);
583 if (!data->drdy_trig)
584 return -ENOMEM;
585
586 data->drdy_trig->dev.parent = dev;
587 ret = devm_iio_trigger_register(dev, data->drdy_trig);
588 if (ret < 0)
589 return ret;
590 }
591
592 ret = devm_iio_triggered_buffer_setup(dev, indio_dev,
593 &iio_pollfunc_store_time,
594 rm3100_trigger_handler,
595 &rm3100_buffer_ops);
596 if (ret < 0)
597 return ret;
598
599 ret = regmap_read(regmap, RM3100_REG_TMRC, &tmp);
600 if (ret < 0)
601 return ret;
602
603 samp_rate_index = tmp - RM3100_TMRC_OFFSET;
604 if (samp_rate_index < 0 || samp_rate_index >= RM3100_SAMP_NUM) {
605 dev_err(dev, "The value read from RM3100_REG_TMRC is invalid!\n");
606 return -EINVAL;
607 }
608 /* Initializing max wait time, which is double conversion time. */
609 data->conversion_time = rm3100_samp_rates[samp_rate_index][2] * 2;
610
611 /* Cycle count values may not be what we want. */
612 if ((tmp - RM3100_TMRC_OFFSET) == 0)
613 rm3100_set_cycle_count(data, 100);
614 else
615 rm3100_set_cycle_count(data, 200);
616
617 return devm_iio_device_register(dev, indio_dev);
618 }
619 EXPORT_SYMBOL_GPL(rm3100_common_probe);
620
621 MODULE_AUTHOR("Song Qiang <songqiang1304521@gmail.com>");
622 MODULE_DESCRIPTION("PNI RM3100 3-axis magnetometer i2c driver");
623 MODULE_LICENSE("GPL v2");
624