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 */
52struct 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
67static 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
101static 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
118static 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
133static 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
143static 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
148static 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
154static IIO_DEV_ATTR_SAMP_FREQ_AVAIL(mag3110_show_samp_freq_avail);
155
156static 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
163static 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
175static 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
181static 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
211static 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 */
218static 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
229static 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;
268fail:
269	mutex_unlock(&data->lock);
270
271	return ret;
272}
273
274static 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		}
315release:
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
347static 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
391static 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
413done:
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
435static 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
453static struct attribute *mag3110_attributes[] = {
454	&iio_dev_attr_sampling_frequency_available.dev_attr.attr,
455	NULL
456};
457
458static const struct attribute_group mag3110_group = {
459	.attrs = mag3110_attributes,
460};
461
462static const struct iio_info mag3110_info = {
463	.attrs = &mag3110_group,
464	.read_raw = &mag3110_read_raw,
465	.write_raw = &mag3110_write_raw,
466};
467
468static const unsigned long mag3110_scan_masks[] = {0x7, 0xf, 0};
469
470static 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
548buffer_cleanup:
549	iio_triggered_buffer_cleanup(indio_dev);
550standby_on_error:
551	mag3110_standby(iio_priv(indio_dev));
552disable_regulators:
553	regulator_disable(data->vddio_reg);
554disable_regulator_vdd:
555	regulator_disable(data->vdd_reg);
556
557	return ret;
558}
559
560static 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
575static 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
601static 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
624static 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
630static const struct i2c_device_id mag3110_id[] = {
631	{ "mag3110", 0 },
632	{ }
633};
634MODULE_DEVICE_TABLE(i2c, mag3110_id);
635
636static const struct of_device_id mag3110_of_match[] = {
637	{ .compatible = "fsl,mag3110" },
638	{ }
639};
640MODULE_DEVICE_TABLE(of, mag3110_of_match);
641
642static 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};
652module_i2c_driver(mag3110_driver);
653
654MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
655MODULE_DESCRIPTION("Freescale MAG3110 magnetometer driver");
656MODULE_LICENSE("GPL");
657