mag3110.c

  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/cleanup.h>
 13#include <linux/module.h>
 14#include <linux/i2c.h>
 15#include <linux/iio/iio.h>
 16#include <linux/iio/sysfs.h>
 17#include <linux/iio/trigger_consumer.h>
 18#include <linux/iio/buffer.h>
 19#include <linux/iio/triggered_buffer.h>
 20#include <linux/delay.h>
 21#include <linux/regulator/consumer.h>
 22
 23#define MAG3110_STATUS 0x00
 24#define MAG3110_OUT_X 0x01 /* MSB first */
 25#define MAG3110_OUT_Y 0x03
 26#define MAG3110_OUT_Z 0x05
 27#define MAG3110_WHO_AM_I 0x07
 28#define MAG3110_SYSMOD 0x08
 29#define MAG3110_OFF_X 0x09 /* MSB first */
 30#define MAG3110_OFF_Y 0x0b
 31#define MAG3110_OFF_Z 0x0d
 32#define MAG3110_DIE_TEMP 0x0f
 33#define MAG3110_CTRL_REG1 0x10
 34#define MAG3110_CTRL_REG2 0x11
 35
 36#define MAG3110_STATUS_DRDY (BIT(2) | BIT(1) | BIT(0))
 37
 38#define MAG3110_CTRL_DR_MASK (BIT(7) | BIT(6) | BIT(5))
 39#define MAG3110_CTRL_DR_SHIFT 5
 40#define MAG3110_CTRL_DR_DEFAULT 0
 41
 42#define MAG3110_SYSMOD_MODE_MASK GENMASK(1, 0)
 43
 44#define MAG3110_CTRL_TM BIT(1) /* trigger single measurement */
 45#define MAG3110_CTRL_AC BIT(0) /* continuous measurements */
 46
 47#define MAG3110_CTRL_AUTO_MRST_EN BIT(7) /* magnetic auto-reset */
 48#define MAG3110_CTRL_RAW BIT(5) /* measurements not user-offset corrected */
 49
 50#define MAG3110_DEVICE_ID 0xc4
 51
 52/* Each client has this additional data */
 53struct mag3110_data {
 54	struct i2c_client *client;
 55	struct mutex lock;
 56	u8 ctrl_reg1;
 57	int sleep_val;
 58	struct regulator *vdd_reg;
 59	struct regulator *vddio_reg;
 60	/* Ensure natural alignment of timestamp */
 61	struct {
 62		__be16 channels[3];
 63		u8 temperature;
 64		aligned_s64 ts;
 65	} scan;
 66};
 67
 68static int mag3110_request(struct mag3110_data *data)
 69{
 70	int ret, tries = 150;
 71
 72	if ((data->ctrl_reg1 & MAG3110_CTRL_AC) == 0) {
 73		/* trigger measurement */
 74		ret = i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
 75			data->ctrl_reg1 | MAG3110_CTRL_TM);
 76		if (ret < 0)
 77			return ret;
 78	}
 79
 80	while (tries-- > 0) {
 81		ret = i2c_smbus_read_byte_data(data->client, MAG3110_STATUS);
 82		if (ret < 0)
 83			return ret;
 84		/* wait for data ready */
 85		if ((ret & MAG3110_STATUS_DRDY) == MAG3110_STATUS_DRDY)
 86			break;
 87
 88		if (data->sleep_val <= 20)
 89			usleep_range(data->sleep_val * 250, data->sleep_val * 500);
 90		else
 91			msleep(20);
 92	}
 93
 94	if (tries < 0) {
 95		dev_err(&data->client->dev, "data not ready\n");
 96		return -EIO;
 97	}
 98
 99	return 0;
100}
101
102static int mag3110_read(struct mag3110_data *data, __be16 buf[3])
103{
104	int ret;
105
106	guard(mutex)(&data->lock);
107	ret = mag3110_request(data);
108	if (ret < 0)
109		return ret;
110	return i2c_smbus_read_i2c_block_data(data->client, MAG3110_OUT_X,
111					     3 * sizeof(__be16), (u8 *) buf);
112}
113
114static ssize_t mag3110_show_int_plus_micros(char *buf,
115	const int (*vals)[2], int n)
116{
117	size_t len = 0;
118
119	while (n-- > 0)
120		len += scnprintf(buf + len, PAGE_SIZE - len,
121			"%d.%06d ", vals[n][0], vals[n][1]);
122
123	/* replace trailing space by newline */
124	buf[len - 1] = '\n';
125
126	return len;
127}
128
129static int mag3110_get_int_plus_micros_index(const int (*vals)[2], int n,
130					int val, int val2)
131{
132	while (n-- > 0)
133		if (val == vals[n][0] && val2 == vals[n][1])
134			return n;
135
136	return -EINVAL;
137}
138
139static const int mag3110_samp_freq[8][2] = {
140	{80, 0}, {40, 0}, {20, 0}, {10, 0}, {5, 0}, {2, 500000},
141	{1, 250000}, {0, 625000}
142};
143
144static ssize_t mag3110_show_samp_freq_avail(struct device *dev,
145				struct device_attribute *attr, char *buf)
146{
147	return mag3110_show_int_plus_micros(buf, mag3110_samp_freq, 8);
148}
149
150static IIO_DEV_ATTR_SAMP_FREQ_AVAIL(mag3110_show_samp_freq_avail);
151
152static int mag3110_get_samp_freq_index(struct mag3110_data *data,
153	int val, int val2)
154{
155	return mag3110_get_int_plus_micros_index(mag3110_samp_freq, 8, val,
156		val2);
157}
158
159static int mag3110_calculate_sleep(struct mag3110_data *data)
160{
161	int ret, i = data->ctrl_reg1 >> MAG3110_CTRL_DR_SHIFT;
162
163	if (mag3110_samp_freq[i][0] > 0)
164		ret = 1000 / mag3110_samp_freq[i][0];
165	else
166		ret = 1000;
167
168	return ret == 0 ? 1 : ret;
169}
170
171static int mag3110_standby(struct mag3110_data *data)
172{
173	return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
174		data->ctrl_reg1 & ~MAG3110_CTRL_AC);
175}
176
177static int mag3110_wait_standby(struct mag3110_data *data)
178{
179	int ret, tries = 30;
180
181	/*
182	 * Takes up to 1/ODR to come out of active mode into stby
183	 * Longest expected period is 12.5seconds.
184	 * We'll sleep for 500ms between checks
185	 */
186	while (tries-- > 0) {
187		ret = i2c_smbus_read_byte_data(data->client, MAG3110_SYSMOD);
188		if (ret < 0) {
189			dev_err(&data->client->dev, "i2c error\n");
190			return ret;
191		}
192		/* wait for standby */
193		if ((ret & MAG3110_SYSMOD_MODE_MASK) == 0)
194			break;
195
196		msleep_interruptible(500);
197	}
198
199	if (tries < 0) {
200		dev_err(&data->client->dev, "device not entering standby mode\n");
201		return -EIO;
202	}
203
204	return 0;
205}
206
207static int mag3110_active(struct mag3110_data *data)
208{
209	return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
210					 data->ctrl_reg1);
211}
212
213/* returns >0 if active, 0 if in standby and <0 on error */
214static int mag3110_is_active(struct mag3110_data *data)
215{
216	int reg;
217
218	reg = i2c_smbus_read_byte_data(data->client, MAG3110_CTRL_REG1);
219	if (reg < 0)
220		return reg;
221
222	return reg & MAG3110_CTRL_AC;
223}
224
225static int mag3110_change_config(struct mag3110_data *data, u8 reg, u8 val)
226{
227	int ret;
228	int is_active;
229
230	guard(mutex)(&data->lock);
231
232	is_active = mag3110_is_active(data);
233	if (is_active < 0)
234		return is_active;
235
236	/* config can only be changed when in standby */
237	if (is_active > 0) {
238		ret = mag3110_standby(data);
239		if (ret < 0)
240			return ret;
241	}
242
243	/*
244	 * After coming out of active we must wait for the part
245	 * to transition to STBY. This can take up to 1 /ODR to occur
246	 */
247	ret = mag3110_wait_standby(data);
248	if (ret < 0)
249		return ret;
250
251	ret = i2c_smbus_write_byte_data(data->client, reg, val);
252	if (ret < 0)
253		return ret;
254
255	if (is_active > 0) {
256		ret = mag3110_active(data);
257		if (ret < 0)
258			return ret;
259	}
260
261	return 0;
262}
263
264static int __mag3110_read_info_raw(struct mag3110_data *data,
265				   struct iio_chan_spec const *chan,
266				   int *val)
267{
268	__be16 buffer[3];
269	int ret;
270
271	switch (chan->type) {
272	case IIO_MAGN: /* in 0.1 uT / LSB */
273		ret = mag3110_read(data, buffer);
274		if (ret < 0)
275			return ret;
276		*val = sign_extend32(be16_to_cpu(buffer[chan->scan_index]),
277				     chan->scan_type.realbits - 1);
278		return IIO_VAL_INT;
279
280	case IIO_TEMP: { /* in 1 C / LSB */
281		guard(mutex)(&data->lock);
282		ret = mag3110_request(data);
283		if (ret < 0)
284			return ret;
285		ret = i2c_smbus_read_byte_data(data->client,
286					       MAG3110_DIE_TEMP);
287		if (ret < 0)
288			return ret;
289		*val = sign_extend32(ret, chan->scan_type.realbits - 1);
290		return IIO_VAL_INT;
291	}
292	default:
293		return -EINVAL;
294	}
295}
296
297static int mag3110_read_raw(struct iio_dev *indio_dev,
298			    struct iio_chan_spec const *chan,
299			    int *val, int *val2, long mask)
300{
301	struct mag3110_data *data = iio_priv(indio_dev);
302	int i, ret;
303
304	switch (mask) {
305	case IIO_CHAN_INFO_RAW:
306		if (!iio_device_claim_direct(indio_dev))
307			return -EBUSY;
308		ret = __mag3110_read_info_raw(data, chan, val);
309		iio_device_release_direct(indio_dev);
310		return ret;
311
312	case IIO_CHAN_INFO_SCALE:
313		switch (chan->type) {
314		case IIO_MAGN:
315			*val = 0;
316			*val2 = 1000;
317			return IIO_VAL_INT_PLUS_MICRO;
318		case IIO_TEMP:
319			*val = 1000;
320			return IIO_VAL_INT;
321		default:
322			return -EINVAL;
323		}
324	case IIO_CHAN_INFO_SAMP_FREQ:
325		i = data->ctrl_reg1 >> MAG3110_CTRL_DR_SHIFT;
326		*val = mag3110_samp_freq[i][0];
327		*val2 = mag3110_samp_freq[i][1];
328		return IIO_VAL_INT_PLUS_MICRO;
329	case IIO_CHAN_INFO_CALIBBIAS:
330		ret = i2c_smbus_read_word_swapped(data->client,
331			MAG3110_OFF_X +	2 * chan->scan_index);
332		if (ret < 0)
333			return ret;
334		*val = sign_extend32(ret >> 1, 14);
335		return IIO_VAL_INT;
336	}
337	return -EINVAL;
338}
339
340static int __mag3110_write_raw(struct mag3110_data *data,
341			      struct iio_chan_spec const *chan,
342			      int val, int val2, long mask)
343{
344	int rate;
345
346	switch (mask) {
347	case IIO_CHAN_INFO_SAMP_FREQ:
348		rate = mag3110_get_samp_freq_index(data, val, val2);
349		if (rate < 0)
350			return -EINVAL;
351
352		data->ctrl_reg1 &= 0xff & ~MAG3110_CTRL_DR_MASK
353					& ~MAG3110_CTRL_AC;
354		data->ctrl_reg1 |= rate << MAG3110_CTRL_DR_SHIFT;
355		data->sleep_val = mag3110_calculate_sleep(data);
356		if (data->sleep_val < 40)
357			data->ctrl_reg1 |= MAG3110_CTRL_AC;
358
359		return mag3110_change_config(data, MAG3110_CTRL_REG1,
360					     data->ctrl_reg1);
361
362	case IIO_CHAN_INFO_CALIBBIAS:
363		if (val < -10000 || val > 10000)
364			return -EINVAL;
365
366		return i2c_smbus_write_word_swapped(data->client,
367			MAG3110_OFF_X + 2 * chan->scan_index, val << 1);
368	default:
369		return -EINVAL;
370	}
371}
372
373static int mag3110_write_raw(struct iio_dev *indio_dev,
374			     struct iio_chan_spec const *chan,
375			     int val, int val2, long mask)
376{
377	struct mag3110_data *data = iio_priv(indio_dev);
378	int ret;
379
380	if (!iio_device_claim_direct(indio_dev))
381		return -EBUSY;
382	ret = __mag3110_write_raw(data, chan, val, val2, mask);
383	iio_device_release_direct(indio_dev);
384
385	return ret;
386}
387
388static irqreturn_t mag3110_trigger_handler(int irq, void *p)
389{
390	struct iio_poll_func *pf = p;
391	struct iio_dev *indio_dev = pf->indio_dev;
392	struct mag3110_data *data = iio_priv(indio_dev);
393	int ret;
394
395	ret = mag3110_read(data, data->scan.channels);
396	if (ret < 0)
397		goto done;
398
399	if (test_bit(3, indio_dev->active_scan_mask)) {
400		ret = i2c_smbus_read_byte_data(data->client,
401			MAG3110_DIE_TEMP);
402		if (ret < 0)
403			goto done;
404		data->scan.temperature = ret;
405	}
406
407	iio_push_to_buffers_with_ts(indio_dev, &data->scan, sizeof(data->scan),
408				    iio_get_time_ns(indio_dev));
409
410done:
411	iio_trigger_notify_done(indio_dev->trig);
412	return IRQ_HANDLED;
413}
414
415#define MAG3110_CHANNEL(axis, idx) { \
416	.type = IIO_MAGN, \
417	.modified = 1, \
418	.channel2 = IIO_MOD_##axis, \
419	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
420		BIT(IIO_CHAN_INFO_CALIBBIAS), \
421	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ) | \
422		BIT(IIO_CHAN_INFO_SCALE), \
423	.scan_index = idx, \
424	.scan_type = { \
425		.sign = 's', \
426		.realbits = 16, \
427		.storagebits = 16, \
428		.endianness = IIO_BE, \
429	}, \
430}
431
432static const struct iio_chan_spec mag3110_channels[] = {
433	MAG3110_CHANNEL(X, 0),
434	MAG3110_CHANNEL(Y, 1),
435	MAG3110_CHANNEL(Z, 2),
436	{
437		.type = IIO_TEMP,
438		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
439			BIT(IIO_CHAN_INFO_SCALE),
440		.scan_index = 3,
441		.scan_type = {
442			.sign = 's',
443			.realbits = 8,
444			.storagebits = 8,
445			},
446	},
447	IIO_CHAN_SOFT_TIMESTAMP(4),
448};
449
450static struct attribute *mag3110_attributes[] = {
451	&iio_dev_attr_sampling_frequency_available.dev_attr.attr,
452	NULL
453};
454
455static const struct attribute_group mag3110_group = {
456	.attrs = mag3110_attributes,
457};
458
459static const struct iio_info mag3110_info = {
460	.attrs = &mag3110_group,
461	.read_raw = &mag3110_read_raw,
462	.write_raw = &mag3110_write_raw,
463};
464
465static const unsigned long mag3110_scan_masks[] = {0x7, 0xf, 0};
466
467static int mag3110_probe(struct i2c_client *client)
468{
469	const struct i2c_device_id *id = i2c_client_get_device_id(client);
470	struct mag3110_data *data;
471	struct iio_dev *indio_dev;
472	int ret;
473
474	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
475	if (!indio_dev)
476		return -ENOMEM;
477
478	data = iio_priv(indio_dev);
479
480	data->vdd_reg = devm_regulator_get(&client->dev, "vdd");
481	if (IS_ERR(data->vdd_reg))
482		return dev_err_probe(&client->dev, PTR_ERR(data->vdd_reg),
483				     "failed to get VDD regulator!\n");
484
485	data->vddio_reg = devm_regulator_get(&client->dev, "vddio");
486	if (IS_ERR(data->vddio_reg))
487		return dev_err_probe(&client->dev, PTR_ERR(data->vddio_reg),
488				     "failed to get VDDIO regulator!\n");
489
490	ret = regulator_enable(data->vdd_reg);
491	if (ret) {
492		dev_err(&client->dev, "failed to enable VDD regulator!\n");
493		return ret;
494	}
495
496	ret = regulator_enable(data->vddio_reg);
497	if (ret) {
498		dev_err(&client->dev, "failed to enable VDDIO regulator!\n");
499		goto disable_regulator_vdd;
500	}
501
502	ret = i2c_smbus_read_byte_data(client, MAG3110_WHO_AM_I);
503	if (ret < 0)
504		goto disable_regulators;
505	if (ret != MAG3110_DEVICE_ID) {
506		ret = -ENODEV;
507		goto disable_regulators;
508	}
509
510	data->client = client;
511	mutex_init(&data->lock);
512
513	i2c_set_clientdata(client, indio_dev);
514	indio_dev->info = &mag3110_info;
515	indio_dev->name = id->name;
516	indio_dev->modes = INDIO_DIRECT_MODE;
517	indio_dev->channels = mag3110_channels;
518	indio_dev->num_channels = ARRAY_SIZE(mag3110_channels);
519	indio_dev->available_scan_masks = mag3110_scan_masks;
520
521	data->ctrl_reg1 = MAG3110_CTRL_DR_DEFAULT << MAG3110_CTRL_DR_SHIFT;
522	data->sleep_val = mag3110_calculate_sleep(data);
523	if (data->sleep_val < 40)
524		data->ctrl_reg1 |= MAG3110_CTRL_AC;
525
526	ret = mag3110_change_config(data, MAG3110_CTRL_REG1, data->ctrl_reg1);
527	if (ret < 0)
528		goto disable_regulators;
529
530	ret = i2c_smbus_write_byte_data(client, MAG3110_CTRL_REG2,
531		MAG3110_CTRL_AUTO_MRST_EN);
532	if (ret < 0)
533		goto standby_on_error;
534
535	ret = iio_triggered_buffer_setup(indio_dev, NULL,
536		mag3110_trigger_handler, NULL);
537	if (ret < 0)
538		goto standby_on_error;
539
540	ret = iio_device_register(indio_dev);
541	if (ret < 0)
542		goto buffer_cleanup;
543	return 0;
544
545buffer_cleanup:
546	iio_triggered_buffer_cleanup(indio_dev);
547standby_on_error:
548	mag3110_standby(iio_priv(indio_dev));
549disable_regulators:
550	regulator_disable(data->vddio_reg);
551disable_regulator_vdd:
552	regulator_disable(data->vdd_reg);
553
554	return ret;
555}
556
557static void mag3110_remove(struct i2c_client *client)
558{
559	struct iio_dev *indio_dev = i2c_get_clientdata(client);
560	struct mag3110_data *data = iio_priv(indio_dev);
561
562	iio_device_unregister(indio_dev);
563	iio_triggered_buffer_cleanup(indio_dev);
564	mag3110_standby(iio_priv(indio_dev));
565	regulator_disable(data->vddio_reg);
566	regulator_disable(data->vdd_reg);
567}
568
569static int mag3110_suspend(struct device *dev)
570{
571	struct mag3110_data *data = iio_priv(i2c_get_clientdata(
572		to_i2c_client(dev)));
573	int ret;
574
575	ret = mag3110_standby(iio_priv(i2c_get_clientdata(
576		to_i2c_client(dev))));
577	if (ret)
578		return ret;
579
580	ret = regulator_disable(data->vddio_reg);
581	if (ret) {
582		dev_err(dev, "failed to disable VDDIO regulator\n");
583		return ret;
584	}
585
586	ret = regulator_disable(data->vdd_reg);
587	if (ret) {
588		dev_err(dev, "failed to disable VDD regulator\n");
589		return ret;
590	}
591
592	return 0;
593}
594
595static int mag3110_resume(struct device *dev)
596{
597	struct mag3110_data *data = iio_priv(i2c_get_clientdata(
598		to_i2c_client(dev)));
599	int ret;
600
601	ret = regulator_enable(data->vdd_reg);
602	if (ret) {
603		dev_err(dev, "failed to enable VDD regulator\n");
604		return ret;
605	}
606
607	ret = regulator_enable(data->vddio_reg);
608	if (ret) {
609		dev_err(dev, "failed to enable VDDIO regulator\n");
610		regulator_disable(data->vdd_reg);
611		return ret;
612	}
613
614	return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
615		data->ctrl_reg1);
616}
617
618static DEFINE_SIMPLE_DEV_PM_OPS(mag3110_pm_ops, mag3110_suspend,
619				mag3110_resume);
620
621static const struct i2c_device_id mag3110_id[] = {
622	{ "mag3110" },
623	{ }
624};
625MODULE_DEVICE_TABLE(i2c, mag3110_id);
626
627static const struct of_device_id mag3110_of_match[] = {
628	{ .compatible = "fsl,mag3110" },
629	{ }
630};
631MODULE_DEVICE_TABLE(of, mag3110_of_match);
632
633static struct i2c_driver mag3110_driver = {
634	.driver = {
635		.name	= "mag3110",
636		.of_match_table = mag3110_of_match,
637		.pm	= pm_sleep_ptr(&mag3110_pm_ops),
638	},
639	.probe = mag3110_probe,
640	.remove = mag3110_remove,
641	.id_table = mag3110_id,
642};
643module_i2c_driver(mag3110_driver);
644
645MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
646MODULE_DESCRIPTION("Freescale MAG3110 magnetometer driver");
647MODULE_LICENSE("GPL");