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]),
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		}
317release:
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
349static 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
393static 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
415done:
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
437static 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
455static struct attribute *mag3110_attributes[] = {
456	&iio_dev_attr_sampling_frequency_available.dev_attr.attr,
457	NULL
458};
459
460static const struct attribute_group mag3110_group = {
461	.attrs = mag3110_attributes,
462};
463
464static const struct iio_info mag3110_info = {
465	.attrs = &mag3110_group,
466	.read_raw = &mag3110_read_raw,
467	.write_raw = &mag3110_write_raw,
468};
469
470static const unsigned long mag3110_scan_masks[] = {0x7, 0xf, 0};
471
472static 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
550buffer_cleanup:
551	iio_triggered_buffer_cleanup(indio_dev);
552standby_on_error:
553	mag3110_standby(iio_priv(indio_dev));
554disable_regulators:
555	regulator_disable(data->vddio_reg);
556disable_regulator_vdd:
557	regulator_disable(data->vdd_reg);
558
559	return ret;
560}
561
562static 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
574static 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
600static 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
623static DEFINE_SIMPLE_DEV_PM_OPS(mag3110_pm_ops, mag3110_suspend,
624				mag3110_resume);
625
626static const struct i2c_device_id mag3110_id[] = {
627	{ "mag3110", 0 },
628	{ }
629};
630MODULE_DEVICE_TABLE(i2c, mag3110_id);
631
632static const struct of_device_id mag3110_of_match[] = {
633	{ .compatible = "fsl,mag3110" },
634	{ }
635};
636MODULE_DEVICE_TABLE(of, mag3110_of_match);
637
638static 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};
648module_i2c_driver(mag3110_driver);
649
650MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
651MODULE_DESCRIPTION("Freescale MAG3110 magnetometer driver");
652MODULE_LICENSE("GPL");
653