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]), 15);
295 			ret = IIO_VAL_INT;
296 			break;
297 		case IIO_TEMP: /* in 1 C / LSB */
298 			mutex_lock(&data->lock);
299 			ret = mag3110_request(data);
300 			if (ret < 0) {
301 				mutex_unlock(&data->lock);
302 				goto release;
303 			}
304 			ret = i2c_smbus_read_byte_data(data->client,
305 				MAG3110_DIE_TEMP);
306 			mutex_unlock(&data->lock);
307 			if (ret < 0)
308 				goto release;
309 			*val = sign_extend32(ret, 7);
310 			ret = IIO_VAL_INT;
311 			break;
312 		default:
313 			ret = -EINVAL;
314 		}
315 release:
316 		iio_device_release_direct_mode(indio_dev);
317 		return ret;
318 
319 	case IIO_CHAN_INFO_SCALE:
320 		switch (chan->type) {
321 		case IIO_MAGN:
322 			*val = 0;
323 			*val2 = 1000;
324 			return IIO_VAL_INT_PLUS_MICRO;
325 		case IIO_TEMP:
326 			*val = 1000;
327 			return IIO_VAL_INT;
328 		default:
329 			return -EINVAL;
330 		}
331 	case IIO_CHAN_INFO_SAMP_FREQ:
332 		i = data->ctrl_reg1 >> MAG3110_CTRL_DR_SHIFT;
333 		*val = mag3110_samp_freq[i][0];
334 		*val2 = mag3110_samp_freq[i][1];
335 		return IIO_VAL_INT_PLUS_MICRO;
336 	case IIO_CHAN_INFO_CALIBBIAS:
337 		ret = i2c_smbus_read_word_swapped(data->client,
338 			MAG3110_OFF_X +	2 * chan->scan_index);
339 		if (ret < 0)
340 			return ret;
341 		*val = sign_extend32(ret >> 1, 14);
342 		return IIO_VAL_INT;
343 	}
344 	return -EINVAL;
345 }
346 
347 static int mag3110_write_raw(struct iio_dev *indio_dev,
348 			     struct iio_chan_spec const *chan,
349 			     int val, int val2, long mask)
350 {
351 	struct mag3110_data *data = iio_priv(indio_dev);
352 	int rate, ret;
353 
354 	ret = iio_device_claim_direct_mode(indio_dev);
355 	if (ret)
356 		return ret;
357 
358 	switch (mask) {
359 	case IIO_CHAN_INFO_SAMP_FREQ:
360 		rate = mag3110_get_samp_freq_index(data, val, val2);
361 		if (rate < 0) {
362 			ret = -EINVAL;
363 			break;
364 		}
365 		data->ctrl_reg1 &= 0xff & ~MAG3110_CTRL_DR_MASK
366 					& ~MAG3110_CTRL_AC;
367 		data->ctrl_reg1 |= rate << MAG3110_CTRL_DR_SHIFT;
368 		data->sleep_val = mag3110_calculate_sleep(data);
369 		if (data->sleep_val < 40)
370 			data->ctrl_reg1 |= MAG3110_CTRL_AC;
371 
372 		ret = mag3110_change_config(data, MAG3110_CTRL_REG1,
373 					    data->ctrl_reg1);
374 		break;
375 	case IIO_CHAN_INFO_CALIBBIAS:
376 		if (val < -10000 || val > 10000) {
377 			ret = -EINVAL;
378 			break;
379 		}
380 		ret = i2c_smbus_write_word_swapped(data->client,
381 			MAG3110_OFF_X + 2 * chan->scan_index, val << 1);
382 		break;
383 	default:
384 		ret = -EINVAL;
385 		break;
386 	}
387 	iio_device_release_direct_mode(indio_dev);
388 	return ret;
389 }
390 
391 static irqreturn_t mag3110_trigger_handler(int irq, void *p)
392 {
393 	struct iio_poll_func *pf = p;
394 	struct iio_dev *indio_dev = pf->indio_dev;
395 	struct mag3110_data *data = iio_priv(indio_dev);
396 	int ret;
397 
398 	ret = mag3110_read(data, data->scan.channels);
399 	if (ret < 0)
400 		goto done;
401 
402 	if (test_bit(3, indio_dev->active_scan_mask)) {
403 		ret = i2c_smbus_read_byte_data(data->client,
404 			MAG3110_DIE_TEMP);
405 		if (ret < 0)
406 			goto done;
407 		data->scan.temperature = ret;
408 	}
409 
410 	iio_push_to_buffers_with_timestamp(indio_dev, &data->scan,
411 		iio_get_time_ns(indio_dev));
412 
413 done:
414 	iio_trigger_notify_done(indio_dev->trig);
415 	return IRQ_HANDLED;
416 }
417 
418 #define MAG3110_CHANNEL(axis, idx) { \
419 	.type = IIO_MAGN, \
420 	.modified = 1, \
421 	.channel2 = IIO_MOD_##axis, \
422 	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
423 		BIT(IIO_CHAN_INFO_CALIBBIAS), \
424 	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ) | \
425 		BIT(IIO_CHAN_INFO_SCALE), \
426 	.scan_index = idx, \
427 	.scan_type = { \
428 		.sign = 's', \
429 		.realbits = 16, \
430 		.storagebits = 16, \
431 		.endianness = IIO_BE, \
432 	}, \
433 }
434 
435 static const struct iio_chan_spec mag3110_channels[] = {
436 	MAG3110_CHANNEL(X, 0),
437 	MAG3110_CHANNEL(Y, 1),
438 	MAG3110_CHANNEL(Z, 2),
439 	{
440 		.type = IIO_TEMP,
441 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
442 			BIT(IIO_CHAN_INFO_SCALE),
443 		.scan_index = 3,
444 		.scan_type = {
445 			.sign = 's',
446 			.realbits = 8,
447 			.storagebits = 8,
448 			},
449 	},
450 	IIO_CHAN_SOFT_TIMESTAMP(4),
451 };
452 
453 static struct attribute *mag3110_attributes[] = {
454 	&iio_dev_attr_sampling_frequency_available.dev_attr.attr,
455 	NULL
456 };
457 
458 static const struct attribute_group mag3110_group = {
459 	.attrs = mag3110_attributes,
460 };
461 
462 static const struct iio_info mag3110_info = {
463 	.attrs = &mag3110_group,
464 	.read_raw = &mag3110_read_raw,
465 	.write_raw = &mag3110_write_raw,
466 };
467 
468 static const unsigned long mag3110_scan_masks[] = {0x7, 0xf, 0};
469 
470 static int mag3110_probe(struct i2c_client *client,
471 			 const struct i2c_device_id *id)
472 {
473 	struct mag3110_data *data;
474 	struct iio_dev *indio_dev;
475 	int ret;
476 
477 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
478 	if (!indio_dev)
479 		return -ENOMEM;
480 
481 	data = iio_priv(indio_dev);
482 
483 	data->vdd_reg = devm_regulator_get(&client->dev, "vdd");
484 	if (IS_ERR(data->vdd_reg))
485 		return dev_err_probe(&client->dev, PTR_ERR(data->vdd_reg),
486 				     "failed to get VDD regulator!\n");
487 
488 	data->vddio_reg = devm_regulator_get(&client->dev, "vddio");
489 	if (IS_ERR(data->vddio_reg))
490 		return dev_err_probe(&client->dev, PTR_ERR(data->vddio_reg),
491 				     "failed to get VDDIO regulator!\n");
492 
493 	ret = regulator_enable(data->vdd_reg);
494 	if (ret) {
495 		dev_err(&client->dev, "failed to enable VDD regulator!\n");
496 		return ret;
497 	}
498 
499 	ret = regulator_enable(data->vddio_reg);
500 	if (ret) {
501 		dev_err(&client->dev, "failed to enable VDDIO regulator!\n");
502 		goto disable_regulator_vdd;
503 	}
504 
505 	ret = i2c_smbus_read_byte_data(client, MAG3110_WHO_AM_I);
506 	if (ret < 0)
507 		goto disable_regulators;
508 	if (ret != MAG3110_DEVICE_ID) {
509 		ret = -ENODEV;
510 		goto disable_regulators;
511 	}
512 
513 	data->client = client;
514 	mutex_init(&data->lock);
515 
516 	i2c_set_clientdata(client, indio_dev);
517 	indio_dev->info = &mag3110_info;
518 	indio_dev->name = id->name;
519 	indio_dev->modes = INDIO_DIRECT_MODE;
520 	indio_dev->channels = mag3110_channels;
521 	indio_dev->num_channels = ARRAY_SIZE(mag3110_channels);
522 	indio_dev->available_scan_masks = mag3110_scan_masks;
523 
524 	data->ctrl_reg1 = MAG3110_CTRL_DR_DEFAULT << MAG3110_CTRL_DR_SHIFT;
525 	data->sleep_val = mag3110_calculate_sleep(data);
526 	if (data->sleep_val < 40)
527 		data->ctrl_reg1 |= MAG3110_CTRL_AC;
528 
529 	ret = mag3110_change_config(data, MAG3110_CTRL_REG1, data->ctrl_reg1);
530 	if (ret < 0)
531 		goto disable_regulators;
532 
533 	ret = i2c_smbus_write_byte_data(client, MAG3110_CTRL_REG2,
534 		MAG3110_CTRL_AUTO_MRST_EN);
535 	if (ret < 0)
536 		goto standby_on_error;
537 
538 	ret = iio_triggered_buffer_setup(indio_dev, NULL,
539 		mag3110_trigger_handler, NULL);
540 	if (ret < 0)
541 		goto standby_on_error;
542 
543 	ret = iio_device_register(indio_dev);
544 	if (ret < 0)
545 		goto buffer_cleanup;
546 	return 0;
547 
548 buffer_cleanup:
549 	iio_triggered_buffer_cleanup(indio_dev);
550 standby_on_error:
551 	mag3110_standby(iio_priv(indio_dev));
552 disable_regulators:
553 	regulator_disable(data->vddio_reg);
554 disable_regulator_vdd:
555 	regulator_disable(data->vdd_reg);
556 
557 	return ret;
558 }
559 
560 static int mag3110_remove(struct i2c_client *client)
561 {
562 	struct iio_dev *indio_dev = i2c_get_clientdata(client);
563 	struct mag3110_data *data = iio_priv(indio_dev);
564 
565 	iio_device_unregister(indio_dev);
566 	iio_triggered_buffer_cleanup(indio_dev);
567 	mag3110_standby(iio_priv(indio_dev));
568 	regulator_disable(data->vddio_reg);
569 	regulator_disable(data->vdd_reg);
570 
571 	return 0;
572 }
573 
574 #ifdef CONFIG_PM_SLEEP
575 static int mag3110_suspend(struct device *dev)
576 {
577 	struct mag3110_data *data = iio_priv(i2c_get_clientdata(
578 		to_i2c_client(dev)));
579 	int ret;
580 
581 	ret = mag3110_standby(iio_priv(i2c_get_clientdata(
582 		to_i2c_client(dev))));
583 	if (ret)
584 		return ret;
585 
586 	ret = regulator_disable(data->vddio_reg);
587 	if (ret) {
588 		dev_err(dev, "failed to disable VDDIO regulator\n");
589 		return ret;
590 	}
591 
592 	ret = regulator_disable(data->vdd_reg);
593 	if (ret) {
594 		dev_err(dev, "failed to disable VDD regulator\n");
595 		return ret;
596 	}
597 
598 	return 0;
599 }
600 
601 static int mag3110_resume(struct device *dev)
602 {
603 	struct mag3110_data *data = iio_priv(i2c_get_clientdata(
604 		to_i2c_client(dev)));
605 	int ret;
606 
607 	ret = regulator_enable(data->vdd_reg);
608 	if (ret) {
609 		dev_err(dev, "failed to enable VDD regulator\n");
610 		return ret;
611 	}
612 
613 	ret = regulator_enable(data->vddio_reg);
614 	if (ret) {
615 		dev_err(dev, "failed to enable VDDIO regulator\n");
616 		regulator_disable(data->vdd_reg);
617 		return ret;
618 	}
619 
620 	return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
621 		data->ctrl_reg1);
622 }
623 
624 static SIMPLE_DEV_PM_OPS(mag3110_pm_ops, mag3110_suspend, mag3110_resume);
625 #define MAG3110_PM_OPS (&mag3110_pm_ops)
626 #else
627 #define MAG3110_PM_OPS NULL
628 #endif
629 
630 static const struct i2c_device_id mag3110_id[] = {
631 	{ "mag3110", 0 },
632 	{ }
633 };
634 MODULE_DEVICE_TABLE(i2c, mag3110_id);
635 
636 static const struct of_device_id mag3110_of_match[] = {
637 	{ .compatible = "fsl,mag3110" },
638 	{ }
639 };
640 MODULE_DEVICE_TABLE(of, mag3110_of_match);
641 
642 static struct i2c_driver mag3110_driver = {
643 	.driver = {
644 		.name	= "mag3110",
645 		.of_match_table = mag3110_of_match,
646 		.pm	= MAG3110_PM_OPS,
647 	},
648 	.probe = mag3110_probe,
649 	.remove = mag3110_remove,
650 	.id_table = mag3110_id,
651 };
652 module_i2c_driver(mag3110_driver);
653 
654 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
655 MODULE_DESCRIPTION("Freescale MAG3110 magnetometer driver");
656 MODULE_LICENSE("GPL");
657