1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * mag3110.c - Support for Freescale MAG3110 magnetometer sensor
4  *
5  * Copyright (c) 2013 Peter Meerwald <pmeerw@pmeerw.net>
6  *
7  * (7-bit I2C slave address 0x0e)
8  *
9  * TODO: irq, user offset, oversampling, continuous mode
10  */
11 
12 #include <linux/module.h>
13 #include <linux/i2c.h>
14 #include <linux/iio/iio.h>
15 #include <linux/iio/sysfs.h>
16 #include <linux/iio/trigger_consumer.h>
17 #include <linux/iio/buffer.h>
18 #include <linux/iio/triggered_buffer.h>
19 #include <linux/delay.h>
20 #include <linux/regulator/consumer.h>
21 
22 #define MAG3110_STATUS 0x00
23 #define MAG3110_OUT_X 0x01 /* MSB first */
24 #define MAG3110_OUT_Y 0x03
25 #define MAG3110_OUT_Z 0x05
26 #define MAG3110_WHO_AM_I 0x07
27 #define MAG3110_SYSMOD 0x08
28 #define MAG3110_OFF_X 0x09 /* MSB first */
29 #define MAG3110_OFF_Y 0x0b
30 #define MAG3110_OFF_Z 0x0d
31 #define MAG3110_DIE_TEMP 0x0f
32 #define MAG3110_CTRL_REG1 0x10
33 #define MAG3110_CTRL_REG2 0x11
34 
35 #define MAG3110_STATUS_DRDY (BIT(2) | BIT(1) | BIT(0))
36 
37 #define MAG3110_CTRL_DR_MASK (BIT(7) | BIT(6) | BIT(5))
38 #define MAG3110_CTRL_DR_SHIFT 5
39 #define MAG3110_CTRL_DR_DEFAULT 0
40 
41 #define MAG3110_SYSMOD_MODE_MASK GENMASK(1, 0)
42 
43 #define MAG3110_CTRL_TM BIT(1) /* trigger single measurement */
44 #define MAG3110_CTRL_AC BIT(0) /* continuous measurements */
45 
46 #define MAG3110_CTRL_AUTO_MRST_EN BIT(7) /* magnetic auto-reset */
47 #define MAG3110_CTRL_RAW BIT(5) /* measurements not user-offset corrected */
48 
49 #define MAG3110_DEVICE_ID 0xc4
50 
51 /* Each client has this additional data */
52 struct mag3110_data {
53 	struct i2c_client *client;
54 	struct mutex lock;
55 	u8 ctrl_reg1;
56 	int sleep_val;
57 	struct regulator *vdd_reg;
58 	struct regulator *vddio_reg;
59 	/* Ensure natural alignment of timestamp */
60 	struct {
61 		__be16 channels[3];
62 		u8 temperature;
63 		s64 ts __aligned(8);
64 	} scan;
65 };
66 
67 static int mag3110_request(struct mag3110_data *data)
68 {
69 	int ret, tries = 150;
70 
71 	if ((data->ctrl_reg1 & MAG3110_CTRL_AC) == 0) {
72 		/* trigger measurement */
73 		ret = i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
74 			data->ctrl_reg1 | MAG3110_CTRL_TM);
75 		if (ret < 0)
76 			return ret;
77 	}
78 
79 	while (tries-- > 0) {
80 		ret = i2c_smbus_read_byte_data(data->client, MAG3110_STATUS);
81 		if (ret < 0)
82 			return ret;
83 		/* wait for data ready */
84 		if ((ret & MAG3110_STATUS_DRDY) == MAG3110_STATUS_DRDY)
85 			break;
86 
87 		if (data->sleep_val <= 20)
88 			usleep_range(data->sleep_val * 250, data->sleep_val * 500);
89 		else
90 			msleep(20);
91 	}
92 
93 	if (tries < 0) {
94 		dev_err(&data->client->dev, "data not ready\n");
95 		return -EIO;
96 	}
97 
98 	return 0;
99 }
100 
101 static int mag3110_read(struct mag3110_data *data, __be16 buf[3])
102 {
103 	int ret;
104 
105 	mutex_lock(&data->lock);
106 	ret = mag3110_request(data);
107 	if (ret < 0) {
108 		mutex_unlock(&data->lock);
109 		return ret;
110 	}
111 	ret = i2c_smbus_read_i2c_block_data(data->client,
112 		MAG3110_OUT_X, 3 * sizeof(__be16), (u8 *) buf);
113 	mutex_unlock(&data->lock);
114 
115 	return ret;
116 }
117 
118 static ssize_t mag3110_show_int_plus_micros(char *buf,
119 	const int (*vals)[2], int n)
120 {
121 	size_t len = 0;
122 
123 	while (n-- > 0)
124 		len += scnprintf(buf + len, PAGE_SIZE - len,
125 			"%d.%06d ", vals[n][0], vals[n][1]);
126 
127 	/* replace trailing space by newline */
128 	buf[len - 1] = '\n';
129 
130 	return len;
131 }
132 
133 static int mag3110_get_int_plus_micros_index(const int (*vals)[2], int n,
134 					int val, int val2)
135 {
136 	while (n-- > 0)
137 		if (val == vals[n][0] && val2 == vals[n][1])
138 			return n;
139 
140 	return -EINVAL;
141 }
142 
143 static const int mag3110_samp_freq[8][2] = {
144 	{80, 0}, {40, 0}, {20, 0}, {10, 0}, {5, 0}, {2, 500000},
145 	{1, 250000}, {0, 625000}
146 };
147 
148 static ssize_t mag3110_show_samp_freq_avail(struct device *dev,
149 				struct device_attribute *attr, char *buf)
150 {
151 	return mag3110_show_int_plus_micros(buf, mag3110_samp_freq, 8);
152 }
153 
154 static IIO_DEV_ATTR_SAMP_FREQ_AVAIL(mag3110_show_samp_freq_avail);
155 
156 static int mag3110_get_samp_freq_index(struct mag3110_data *data,
157 	int val, int val2)
158 {
159 	return mag3110_get_int_plus_micros_index(mag3110_samp_freq, 8, val,
160 		val2);
161 }
162 
163 static int mag3110_calculate_sleep(struct mag3110_data *data)
164 {
165 	int ret, i = data->ctrl_reg1 >> MAG3110_CTRL_DR_SHIFT;
166 
167 	if (mag3110_samp_freq[i][0] > 0)
168 		ret = 1000 / mag3110_samp_freq[i][0];
169 	else
170 		ret = 1000;
171 
172 	return ret == 0 ? 1 : ret;
173 }
174 
175 static int mag3110_standby(struct mag3110_data *data)
176 {
177 	return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
178 		data->ctrl_reg1 & ~MAG3110_CTRL_AC);
179 }
180 
181 static int mag3110_wait_standby(struct mag3110_data *data)
182 {
183 	int ret, tries = 30;
184 
185 	/*
186 	 * Takes up to 1/ODR to come out of active mode into stby
187 	 * Longest expected period is 12.5seconds.
188 	 * We'll sleep for 500ms between checks
189 	 */
190 	while (tries-- > 0) {
191 		ret = i2c_smbus_read_byte_data(data->client, MAG3110_SYSMOD);
192 		if (ret < 0) {
193 			dev_err(&data->client->dev, "i2c error\n");
194 			return ret;
195 		}
196 		/* wait for standby */
197 		if ((ret & MAG3110_SYSMOD_MODE_MASK) == 0)
198 			break;
199 
200 		msleep_interruptible(500);
201 	}
202 
203 	if (tries < 0) {
204 		dev_err(&data->client->dev, "device not entering standby mode\n");
205 		return -EIO;
206 	}
207 
208 	return 0;
209 }
210 
211 static int mag3110_active(struct mag3110_data *data)
212 {
213 	return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
214 					 data->ctrl_reg1);
215 }
216 
217 /* returns >0 if active, 0 if in standby and <0 on error */
218 static int mag3110_is_active(struct mag3110_data *data)
219 {
220 	int reg;
221 
222 	reg = i2c_smbus_read_byte_data(data->client, MAG3110_CTRL_REG1);
223 	if (reg < 0)
224 		return reg;
225 
226 	return reg & MAG3110_CTRL_AC;
227 }
228 
229 static int mag3110_change_config(struct mag3110_data *data, u8 reg, u8 val)
230 {
231 	int ret;
232 	int is_active;
233 
234 	mutex_lock(&data->lock);
235 
236 	is_active = mag3110_is_active(data);
237 	if (is_active < 0) {
238 		ret = is_active;
239 		goto fail;
240 	}
241 
242 	/* config can only be changed when in standby */
243 	if (is_active > 0) {
244 		ret = mag3110_standby(data);
245 		if (ret < 0)
246 			goto fail;
247 	}
248 
249 	/*
250 	 * After coming out of active we must wait for the part
251 	 * to transition to STBY. This can take up to 1 /ODR to occur
252 	 */
253 	ret = mag3110_wait_standby(data);
254 	if (ret < 0)
255 		goto fail;
256 
257 	ret = i2c_smbus_write_byte_data(data->client, reg, val);
258 	if (ret < 0)
259 		goto fail;
260 
261 	if (is_active > 0) {
262 		ret = mag3110_active(data);
263 		if (ret < 0)
264 			goto fail;
265 	}
266 
267 	ret = 0;
268 fail:
269 	mutex_unlock(&data->lock);
270 
271 	return ret;
272 }
273 
274 static int mag3110_read_raw(struct iio_dev *indio_dev,
275 			    struct iio_chan_spec const *chan,
276 			    int *val, int *val2, long mask)
277 {
278 	struct mag3110_data *data = iio_priv(indio_dev);
279 	__be16 buffer[3];
280 	int i, ret;
281 
282 	switch (mask) {
283 	case IIO_CHAN_INFO_RAW:
284 		ret = iio_device_claim_direct_mode(indio_dev);
285 		if (ret)
286 			return ret;
287 
288 		switch (chan->type) {
289 		case IIO_MAGN: /* in 0.1 uT / LSB */
290 			ret = mag3110_read(data, buffer);
291 			if (ret < 0)
292 				goto release;
293 			*val = sign_extend32(
294 				be16_to_cpu(buffer[chan->scan_index]),
295 					    chan->scan_type.realbits - 1);
296 			ret = IIO_VAL_INT;
297 			break;
298 		case IIO_TEMP: /* in 1 C / LSB */
299 			mutex_lock(&data->lock);
300 			ret = mag3110_request(data);
301 			if (ret < 0) {
302 				mutex_unlock(&data->lock);
303 				goto release;
304 			}
305 			ret = i2c_smbus_read_byte_data(data->client,
306 				MAG3110_DIE_TEMP);
307 			mutex_unlock(&data->lock);
308 			if (ret < 0)
309 				goto release;
310 			*val = sign_extend32(ret,
311 					     chan->scan_type.realbits - 1);
312 			ret = IIO_VAL_INT;
313 			break;
314 		default:
315 			ret = -EINVAL;
316 		}
317 release:
318 		iio_device_release_direct_mode(indio_dev);
319 		return ret;
320 
321 	case IIO_CHAN_INFO_SCALE:
322 		switch (chan->type) {
323 		case IIO_MAGN:
324 			*val = 0;
325 			*val2 = 1000;
326 			return IIO_VAL_INT_PLUS_MICRO;
327 		case IIO_TEMP:
328 			*val = 1000;
329 			return IIO_VAL_INT;
330 		default:
331 			return -EINVAL;
332 		}
333 	case IIO_CHAN_INFO_SAMP_FREQ:
334 		i = data->ctrl_reg1 >> MAG3110_CTRL_DR_SHIFT;
335 		*val = mag3110_samp_freq[i][0];
336 		*val2 = mag3110_samp_freq[i][1];
337 		return IIO_VAL_INT_PLUS_MICRO;
338 	case IIO_CHAN_INFO_CALIBBIAS:
339 		ret = i2c_smbus_read_word_swapped(data->client,
340 			MAG3110_OFF_X +	2 * chan->scan_index);
341 		if (ret < 0)
342 			return ret;
343 		*val = sign_extend32(ret >> 1, 14);
344 		return IIO_VAL_INT;
345 	}
346 	return -EINVAL;
347 }
348 
349 static int mag3110_write_raw(struct iio_dev *indio_dev,
350 			     struct iio_chan_spec const *chan,
351 			     int val, int val2, long mask)
352 {
353 	struct mag3110_data *data = iio_priv(indio_dev);
354 	int rate, ret;
355 
356 	ret = iio_device_claim_direct_mode(indio_dev);
357 	if (ret)
358 		return ret;
359 
360 	switch (mask) {
361 	case IIO_CHAN_INFO_SAMP_FREQ:
362 		rate = mag3110_get_samp_freq_index(data, val, val2);
363 		if (rate < 0) {
364 			ret = -EINVAL;
365 			break;
366 		}
367 		data->ctrl_reg1 &= 0xff & ~MAG3110_CTRL_DR_MASK
368 					& ~MAG3110_CTRL_AC;
369 		data->ctrl_reg1 |= rate << MAG3110_CTRL_DR_SHIFT;
370 		data->sleep_val = mag3110_calculate_sleep(data);
371 		if (data->sleep_val < 40)
372 			data->ctrl_reg1 |= MAG3110_CTRL_AC;
373 
374 		ret = mag3110_change_config(data, MAG3110_CTRL_REG1,
375 					    data->ctrl_reg1);
376 		break;
377 	case IIO_CHAN_INFO_CALIBBIAS:
378 		if (val < -10000 || val > 10000) {
379 			ret = -EINVAL;
380 			break;
381 		}
382 		ret = i2c_smbus_write_word_swapped(data->client,
383 			MAG3110_OFF_X + 2 * chan->scan_index, val << 1);
384 		break;
385 	default:
386 		ret = -EINVAL;
387 		break;
388 	}
389 	iio_device_release_direct_mode(indio_dev);
390 	return ret;
391 }
392 
393 static irqreturn_t mag3110_trigger_handler(int irq, void *p)
394 {
395 	struct iio_poll_func *pf = p;
396 	struct iio_dev *indio_dev = pf->indio_dev;
397 	struct mag3110_data *data = iio_priv(indio_dev);
398 	int ret;
399 
400 	ret = mag3110_read(data, data->scan.channels);
401 	if (ret < 0)
402 		goto done;
403 
404 	if (test_bit(3, indio_dev->active_scan_mask)) {
405 		ret = i2c_smbus_read_byte_data(data->client,
406 			MAG3110_DIE_TEMP);
407 		if (ret < 0)
408 			goto done;
409 		data->scan.temperature = ret;
410 	}
411 
412 	iio_push_to_buffers_with_timestamp(indio_dev, &data->scan,
413 		iio_get_time_ns(indio_dev));
414 
415 done:
416 	iio_trigger_notify_done(indio_dev->trig);
417 	return IRQ_HANDLED;
418 }
419 
420 #define MAG3110_CHANNEL(axis, idx) { \
421 	.type = IIO_MAGN, \
422 	.modified = 1, \
423 	.channel2 = IIO_MOD_##axis, \
424 	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
425 		BIT(IIO_CHAN_INFO_CALIBBIAS), \
426 	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ) | \
427 		BIT(IIO_CHAN_INFO_SCALE), \
428 	.scan_index = idx, \
429 	.scan_type = { \
430 		.sign = 's', \
431 		.realbits = 16, \
432 		.storagebits = 16, \
433 		.endianness = IIO_BE, \
434 	}, \
435 }
436 
437 static const struct iio_chan_spec mag3110_channels[] = {
438 	MAG3110_CHANNEL(X, 0),
439 	MAG3110_CHANNEL(Y, 1),
440 	MAG3110_CHANNEL(Z, 2),
441 	{
442 		.type = IIO_TEMP,
443 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
444 			BIT(IIO_CHAN_INFO_SCALE),
445 		.scan_index = 3,
446 		.scan_type = {
447 			.sign = 's',
448 			.realbits = 8,
449 			.storagebits = 8,
450 			},
451 	},
452 	IIO_CHAN_SOFT_TIMESTAMP(4),
453 };
454 
455 static struct attribute *mag3110_attributes[] = {
456 	&iio_dev_attr_sampling_frequency_available.dev_attr.attr,
457 	NULL
458 };
459 
460 static const struct attribute_group mag3110_group = {
461 	.attrs = mag3110_attributes,
462 };
463 
464 static const struct iio_info mag3110_info = {
465 	.attrs = &mag3110_group,
466 	.read_raw = &mag3110_read_raw,
467 	.write_raw = &mag3110_write_raw,
468 };
469 
470 static const unsigned long mag3110_scan_masks[] = {0x7, 0xf, 0};
471 
472 static int mag3110_probe(struct i2c_client *client)
473 {
474 	const struct i2c_device_id *id = i2c_client_get_device_id(client);
475 	struct mag3110_data *data;
476 	struct iio_dev *indio_dev;
477 	int ret;
478 
479 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
480 	if (!indio_dev)
481 		return -ENOMEM;
482 
483 	data = iio_priv(indio_dev);
484 
485 	data->vdd_reg = devm_regulator_get(&client->dev, "vdd");
486 	if (IS_ERR(data->vdd_reg))
487 		return dev_err_probe(&client->dev, PTR_ERR(data->vdd_reg),
488 				     "failed to get VDD regulator!\n");
489 
490 	data->vddio_reg = devm_regulator_get(&client->dev, "vddio");
491 	if (IS_ERR(data->vddio_reg))
492 		return dev_err_probe(&client->dev, PTR_ERR(data->vddio_reg),
493 				     "failed to get VDDIO regulator!\n");
494 
495 	ret = regulator_enable(data->vdd_reg);
496 	if (ret) {
497 		dev_err(&client->dev, "failed to enable VDD regulator!\n");
498 		return ret;
499 	}
500 
501 	ret = regulator_enable(data->vddio_reg);
502 	if (ret) {
503 		dev_err(&client->dev, "failed to enable VDDIO regulator!\n");
504 		goto disable_regulator_vdd;
505 	}
506 
507 	ret = i2c_smbus_read_byte_data(client, MAG3110_WHO_AM_I);
508 	if (ret < 0)
509 		goto disable_regulators;
510 	if (ret != MAG3110_DEVICE_ID) {
511 		ret = -ENODEV;
512 		goto disable_regulators;
513 	}
514 
515 	data->client = client;
516 	mutex_init(&data->lock);
517 
518 	i2c_set_clientdata(client, indio_dev);
519 	indio_dev->info = &mag3110_info;
520 	indio_dev->name = id->name;
521 	indio_dev->modes = INDIO_DIRECT_MODE;
522 	indio_dev->channels = mag3110_channels;
523 	indio_dev->num_channels = ARRAY_SIZE(mag3110_channels);
524 	indio_dev->available_scan_masks = mag3110_scan_masks;
525 
526 	data->ctrl_reg1 = MAG3110_CTRL_DR_DEFAULT << MAG3110_CTRL_DR_SHIFT;
527 	data->sleep_val = mag3110_calculate_sleep(data);
528 	if (data->sleep_val < 40)
529 		data->ctrl_reg1 |= MAG3110_CTRL_AC;
530 
531 	ret = mag3110_change_config(data, MAG3110_CTRL_REG1, data->ctrl_reg1);
532 	if (ret < 0)
533 		goto disable_regulators;
534 
535 	ret = i2c_smbus_write_byte_data(client, MAG3110_CTRL_REG2,
536 		MAG3110_CTRL_AUTO_MRST_EN);
537 	if (ret < 0)
538 		goto standby_on_error;
539 
540 	ret = iio_triggered_buffer_setup(indio_dev, NULL,
541 		mag3110_trigger_handler, NULL);
542 	if (ret < 0)
543 		goto standby_on_error;
544 
545 	ret = iio_device_register(indio_dev);
546 	if (ret < 0)
547 		goto buffer_cleanup;
548 	return 0;
549 
550 buffer_cleanup:
551 	iio_triggered_buffer_cleanup(indio_dev);
552 standby_on_error:
553 	mag3110_standby(iio_priv(indio_dev));
554 disable_regulators:
555 	regulator_disable(data->vddio_reg);
556 disable_regulator_vdd:
557 	regulator_disable(data->vdd_reg);
558 
559 	return ret;
560 }
561 
562 static void mag3110_remove(struct i2c_client *client)
563 {
564 	struct iio_dev *indio_dev = i2c_get_clientdata(client);
565 	struct mag3110_data *data = iio_priv(indio_dev);
566 
567 	iio_device_unregister(indio_dev);
568 	iio_triggered_buffer_cleanup(indio_dev);
569 	mag3110_standby(iio_priv(indio_dev));
570 	regulator_disable(data->vddio_reg);
571 	regulator_disable(data->vdd_reg);
572 }
573 
574 static int mag3110_suspend(struct device *dev)
575 {
576 	struct mag3110_data *data = iio_priv(i2c_get_clientdata(
577 		to_i2c_client(dev)));
578 	int ret;
579 
580 	ret = mag3110_standby(iio_priv(i2c_get_clientdata(
581 		to_i2c_client(dev))));
582 	if (ret)
583 		return ret;
584 
585 	ret = regulator_disable(data->vddio_reg);
586 	if (ret) {
587 		dev_err(dev, "failed to disable VDDIO regulator\n");
588 		return ret;
589 	}
590 
591 	ret = regulator_disable(data->vdd_reg);
592 	if (ret) {
593 		dev_err(dev, "failed to disable VDD regulator\n");
594 		return ret;
595 	}
596 
597 	return 0;
598 }
599 
600 static int mag3110_resume(struct device *dev)
601 {
602 	struct mag3110_data *data = iio_priv(i2c_get_clientdata(
603 		to_i2c_client(dev)));
604 	int ret;
605 
606 	ret = regulator_enable(data->vdd_reg);
607 	if (ret) {
608 		dev_err(dev, "failed to enable VDD regulator\n");
609 		return ret;
610 	}
611 
612 	ret = regulator_enable(data->vddio_reg);
613 	if (ret) {
614 		dev_err(dev, "failed to enable VDDIO regulator\n");
615 		regulator_disable(data->vdd_reg);
616 		return ret;
617 	}
618 
619 	return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
620 		data->ctrl_reg1);
621 }
622 
623 static DEFINE_SIMPLE_DEV_PM_OPS(mag3110_pm_ops, mag3110_suspend,
624 				mag3110_resume);
625 
626 static const struct i2c_device_id mag3110_id[] = {
627 	{ "mag3110", 0 },
628 	{ }
629 };
630 MODULE_DEVICE_TABLE(i2c, mag3110_id);
631 
632 static const struct of_device_id mag3110_of_match[] = {
633 	{ .compatible = "fsl,mag3110" },
634 	{ }
635 };
636 MODULE_DEVICE_TABLE(of, mag3110_of_match);
637 
638 static struct i2c_driver mag3110_driver = {
639 	.driver = {
640 		.name	= "mag3110",
641 		.of_match_table = mag3110_of_match,
642 		.pm	= pm_sleep_ptr(&mag3110_pm_ops),
643 	},
644 	.probe = mag3110_probe,
645 	.remove = mag3110_remove,
646 	.id_table = mag3110_id,
647 };
648 module_i2c_driver(mag3110_driver);
649 
650 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
651 MODULE_DESCRIPTION("Freescale MAG3110 magnetometer driver");
652 MODULE_LICENSE("GPL");
653