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
rm3100_thread_fn(int irq,void * d)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
rm3100_irq_handler(int irq,void * d)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
rm3100_wait_measurement(struct rm3100_data * data)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
rm3100_read_mag(struct rm3100_data * data,int idx,int * val)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
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 .postdisable = rm3100_buffer_postdisable,
467 };
468
rm3100_trigger_handler(int irq,void * p)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
rm3100_common_probe(struct device * dev,struct regmap * regmap,int irq)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
