1// SPDX-License-Identifier: GPL-2.0
2/*
3 * MS5611 pressure and temperature sensor driver
4 *
5 * Copyright (c) Tomasz Duszynski <tduszyns@gmail.com>
6 *
7 * Data sheet:
8 *  http://www.meas-spec.com/downloads/MS5611-01BA03.pdf
9 *  http://www.meas-spec.com/downloads/MS5607-02BA03.pdf
10 *
11 */
12
13#include <linux/module.h>
14#include <linux/iio/iio.h>
15#include <linux/delay.h>
16#include <linux/regulator/consumer.h>
17
18#include <linux/iio/sysfs.h>
19#include <linux/iio/buffer.h>
20#include <linux/iio/triggered_buffer.h>
21#include <linux/iio/trigger_consumer.h>
22#include "ms5611.h"
23
24#define MS5611_INIT_OSR(_cmd, _conv_usec, _rate) \
25	{ .cmd = _cmd, .conv_usec = _conv_usec, .rate = _rate }
26
27static const struct ms5611_osr ms5611_avail_pressure_osr[] = {
28	MS5611_INIT_OSR(0x40, 600,  256),
29	MS5611_INIT_OSR(0x42, 1170, 512),
30	MS5611_INIT_OSR(0x44, 2280, 1024),
31	MS5611_INIT_OSR(0x46, 4540, 2048),
32	MS5611_INIT_OSR(0x48, 9040, 4096)
33};
34
35static const struct ms5611_osr ms5611_avail_temp_osr[] = {
36	MS5611_INIT_OSR(0x50, 600,  256),
37	MS5611_INIT_OSR(0x52, 1170, 512),
38	MS5611_INIT_OSR(0x54, 2280, 1024),
39	MS5611_INIT_OSR(0x56, 4540, 2048),
40	MS5611_INIT_OSR(0x58, 9040, 4096)
41};
42
43static const char ms5611_show_osr[] = "256 512 1024 2048 4096";
44
45static IIO_CONST_ATTR(oversampling_ratio_available, ms5611_show_osr);
46
47static struct attribute *ms5611_attributes[] = {
48	&iio_const_attr_oversampling_ratio_available.dev_attr.attr,
49	NULL,
50};
51
52static const struct attribute_group ms5611_attribute_group = {
53	.attrs = ms5611_attributes,
54};
55
56static bool ms5611_prom_is_valid(u16 *prom, size_t len)
57{
58	int i, j;
59	uint16_t crc = 0, crc_orig = prom[7] & 0x000F;
60
61	prom[7] &= 0xFF00;
62
63	for (i = 0; i < len * 2; i++) {
64		if (i % 2 == 1)
65			crc ^= prom[i >> 1] & 0x00FF;
66		else
67			crc ^= prom[i >> 1] >> 8;
68
69		for (j = 0; j < 8; j++) {
70			if (crc & 0x8000)
71				crc = (crc << 1) ^ 0x3000;
72			else
73				crc <<= 1;
74		}
75	}
76
77	crc = (crc >> 12) & 0x000F;
78
79	return crc == crc_orig;
80}
81
82static int ms5611_read_prom(struct iio_dev *indio_dev)
83{
84	int ret, i;
85	struct ms5611_state *st = iio_priv(indio_dev);
86
87	for (i = 0; i < MS5611_PROM_WORDS_NB; i++) {
88		ret = st->read_prom_word(st, i, &st->prom[i]);
89		if (ret < 0) {
90			dev_err(&indio_dev->dev,
91				"failed to read prom at %d\n", i);
92			return ret;
93		}
94	}
95
96	if (!ms5611_prom_is_valid(st->prom, MS5611_PROM_WORDS_NB)) {
97		dev_err(&indio_dev->dev, "PROM integrity check failed\n");
98		return -ENODEV;
99	}
100
101	return 0;
102}
103
104static int ms5611_read_temp_and_pressure(struct iio_dev *indio_dev,
105					 s32 *temp, s32 *pressure)
106{
107	int ret;
108	struct ms5611_state *st = iio_priv(indio_dev);
109
110	ret = st->read_adc_temp_and_pressure(st, temp, pressure);
111	if (ret < 0) {
112		dev_err(&indio_dev->dev,
113			"failed to read temperature and pressure\n");
114		return ret;
115	}
116
117	return st->compensate_temp_and_pressure(st, temp, pressure);
118}
119
120static int ms5611_temp_and_pressure_compensate(struct ms5611_state *st,
121					       s32 *temp, s32 *pressure)
122{
123	s32 t = *temp, p = *pressure;
124	s64 off, sens, dt;
125
126	dt = t - (st->prom[5] << 8);
127	off = ((s64)st->prom[2] << 16) + ((st->prom[4] * dt) >> 7);
128	sens = ((s64)st->prom[1] << 15) + ((st->prom[3] * dt) >> 8);
129
130	t = 2000 + ((st->prom[6] * dt) >> 23);
131	if (t < 2000) {
132		s64 off2, sens2, t2;
133
134		t2 = (dt * dt) >> 31;
135		off2 = (5 * (t - 2000) * (t - 2000)) >> 1;
136		sens2 = off2 >> 1;
137
138		if (t < -1500) {
139			s64 tmp = (t + 1500) * (t + 1500);
140
141			off2 += 7 * tmp;
142			sens2 += (11 * tmp) >> 1;
143		}
144
145		t -= t2;
146		off -= off2;
147		sens -= sens2;
148	}
149
150	*temp = t;
151	*pressure = (((p * sens) >> 21) - off) >> 15;
152
153	return 0;
154}
155
156static int ms5607_temp_and_pressure_compensate(struct ms5611_state *st,
157					       s32 *temp, s32 *pressure)
158{
159	s32 t = *temp, p = *pressure;
160	s64 off, sens, dt;
161
162	dt = t - (st->prom[5] << 8);
163	off = ((s64)st->prom[2] << 17) + ((st->prom[4] * dt) >> 6);
164	sens = ((s64)st->prom[1] << 16) + ((st->prom[3] * dt) >> 7);
165
166	t = 2000 + ((st->prom[6] * dt) >> 23);
167	if (t < 2000) {
168		s64 off2, sens2, t2, tmp;
169
170		t2 = (dt * dt) >> 31;
171		tmp = (t - 2000) * (t - 2000);
172		off2 = (61 * tmp) >> 4;
173		sens2 = tmp << 1;
174
175		if (t < -1500) {
176			tmp = (t + 1500) * (t + 1500);
177			off2 += 15 * tmp;
178			sens2 += 8 * tmp;
179		}
180
181		t -= t2;
182		off -= off2;
183		sens -= sens2;
184	}
185
186	*temp = t;
187	*pressure = (((p * sens) >> 21) - off) >> 15;
188
189	return 0;
190}
191
192static int ms5611_reset(struct iio_dev *indio_dev)
193{
194	int ret;
195	struct ms5611_state *st = iio_priv(indio_dev);
196
197	ret = st->reset(st);
198	if (ret < 0) {
199		dev_err(&indio_dev->dev, "failed to reset device\n");
200		return ret;
201	}
202
203	usleep_range(3000, 4000);
204
205	return 0;
206}
207
208static irqreturn_t ms5611_trigger_handler(int irq, void *p)
209{
210	struct iio_poll_func *pf = p;
211	struct iio_dev *indio_dev = pf->indio_dev;
212	struct ms5611_state *st = iio_priv(indio_dev);
213	/* Ensure buffer elements are naturally aligned */
214	struct {
215		s32 channels[2];
216		s64 ts __aligned(8);
217	} scan;
218	int ret;
219
220	mutex_lock(&st->lock);
221	ret = ms5611_read_temp_and_pressure(indio_dev, &scan.channels[1],
222					    &scan.channels[0]);
223	mutex_unlock(&st->lock);
224	if (ret < 0)
225		goto err;
226
227	iio_push_to_buffers_with_timestamp(indio_dev, &scan,
228					   iio_get_time_ns(indio_dev));
229
230err:
231	iio_trigger_notify_done(indio_dev->trig);
232
233	return IRQ_HANDLED;
234}
235
236static int ms5611_read_raw(struct iio_dev *indio_dev,
237			   struct iio_chan_spec const *chan,
238			   int *val, int *val2, long mask)
239{
240	int ret;
241	s32 temp, pressure;
242	struct ms5611_state *st = iio_priv(indio_dev);
243
244	switch (mask) {
245	case IIO_CHAN_INFO_PROCESSED:
246		mutex_lock(&st->lock);
247		ret = ms5611_read_temp_and_pressure(indio_dev,
248						    &temp, &pressure);
249		mutex_unlock(&st->lock);
250		if (ret < 0)
251			return ret;
252
253		switch (chan->type) {
254		case IIO_TEMP:
255			*val = temp * 10;
256			return IIO_VAL_INT;
257		case IIO_PRESSURE:
258			*val = pressure / 1000;
259			*val2 = (pressure % 1000) * 1000;
260			return IIO_VAL_INT_PLUS_MICRO;
261		default:
262			return -EINVAL;
263		}
264	case IIO_CHAN_INFO_SCALE:
265		switch (chan->type) {
266		case IIO_TEMP:
267			*val = 10;
268			return IIO_VAL_INT;
269		case IIO_PRESSURE:
270			*val = 0;
271			*val2 = 1000;
272			return IIO_VAL_INT_PLUS_MICRO;
273		default:
274			return -EINVAL;
275		}
276	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
277		if (chan->type != IIO_TEMP && chan->type != IIO_PRESSURE)
278			break;
279		mutex_lock(&st->lock);
280		if (chan->type == IIO_TEMP)
281			*val = (int)st->temp_osr->rate;
282		else
283			*val = (int)st->pressure_osr->rate;
284		mutex_unlock(&st->lock);
285		return IIO_VAL_INT;
286	}
287
288	return -EINVAL;
289}
290
291static const struct ms5611_osr *ms5611_find_osr(int rate,
292						const struct ms5611_osr *osr,
293						size_t count)
294{
295	unsigned int r;
296
297	for (r = 0; r < count; r++)
298		if ((unsigned short)rate == osr[r].rate)
299			break;
300	if (r >= count)
301		return NULL;
302	return &osr[r];
303}
304
305static int ms5611_write_raw(struct iio_dev *indio_dev,
306			    struct iio_chan_spec const *chan,
307			    int val, int val2, long mask)
308{
309	struct ms5611_state *st = iio_priv(indio_dev);
310	const struct ms5611_osr *osr = NULL;
311	int ret;
312
313	if (mask != IIO_CHAN_INFO_OVERSAMPLING_RATIO)
314		return -EINVAL;
315
316	if (chan->type == IIO_TEMP)
317		osr = ms5611_find_osr(val, ms5611_avail_temp_osr,
318				      ARRAY_SIZE(ms5611_avail_temp_osr));
319	else if (chan->type == IIO_PRESSURE)
320		osr = ms5611_find_osr(val, ms5611_avail_pressure_osr,
321				      ARRAY_SIZE(ms5611_avail_pressure_osr));
322	if (!osr)
323		return -EINVAL;
324
325	ret = iio_device_claim_direct_mode(indio_dev);
326	if (ret)
327		return ret;
328
329	mutex_lock(&st->lock);
330
331	if (chan->type == IIO_TEMP)
332		st->temp_osr = osr;
333	else
334		st->pressure_osr = osr;
335
336	mutex_unlock(&st->lock);
337	iio_device_release_direct_mode(indio_dev);
338
339	return 0;
340}
341
342static const unsigned long ms5611_scan_masks[] = {0x3, 0};
343
344static const struct iio_chan_spec ms5611_channels[] = {
345	{
346		.type = IIO_PRESSURE,
347		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
348			BIT(IIO_CHAN_INFO_SCALE) |
349			BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
350		.scan_index = 0,
351		.scan_type = {
352			.sign = 's',
353			.realbits = 32,
354			.storagebits = 32,
355			.endianness = IIO_CPU,
356		},
357	},
358	{
359		.type = IIO_TEMP,
360		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
361			BIT(IIO_CHAN_INFO_SCALE) |
362			BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
363		.scan_index = 1,
364		.scan_type = {
365			.sign = 's',
366			.realbits = 32,
367			.storagebits = 32,
368			.endianness = IIO_CPU,
369		},
370	},
371	IIO_CHAN_SOFT_TIMESTAMP(2),
372};
373
374static const struct iio_info ms5611_info = {
375	.read_raw = &ms5611_read_raw,
376	.write_raw = &ms5611_write_raw,
377	.attrs = &ms5611_attribute_group,
378};
379
380static int ms5611_init(struct iio_dev *indio_dev)
381{
382	int ret;
383
384	/* Enable attached regulator if any. */
385	ret = devm_regulator_get_enable(indio_dev->dev.parent, "vdd");
386	if (ret)
387		return ret;
388
389	ret = ms5611_reset(indio_dev);
390	if (ret < 0)
391		return ret;
392
393	ret = ms5611_read_prom(indio_dev);
394	if (ret < 0)
395		return ret;
396
397	return 0;
398}
399
400int ms5611_probe(struct iio_dev *indio_dev, struct device *dev,
401		 const char *name, int type)
402{
403	int ret;
404	struct ms5611_state *st = iio_priv(indio_dev);
405
406	mutex_init(&st->lock);
407
408	switch (type) {
409	case MS5611:
410		st->compensate_temp_and_pressure =
411			ms5611_temp_and_pressure_compensate;
412		break;
413	case MS5607:
414		st->compensate_temp_and_pressure =
415			ms5607_temp_and_pressure_compensate;
416		break;
417	default:
418		return -EINVAL;
419	}
420
421	st->temp_osr =
422		&ms5611_avail_temp_osr[ARRAY_SIZE(ms5611_avail_temp_osr) - 1];
423	st->pressure_osr =
424		&ms5611_avail_pressure_osr[ARRAY_SIZE(ms5611_avail_pressure_osr)
425					   - 1];
426	indio_dev->name = name;
427	indio_dev->info = &ms5611_info;
428	indio_dev->channels = ms5611_channels;
429	indio_dev->num_channels = ARRAY_SIZE(ms5611_channels);
430	indio_dev->modes = INDIO_DIRECT_MODE;
431	indio_dev->available_scan_masks = ms5611_scan_masks;
432
433	ret = ms5611_init(indio_dev);
434	if (ret < 0)
435		return ret;
436
437	ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL,
438					 ms5611_trigger_handler, NULL);
439	if (ret < 0) {
440		dev_err(dev, "iio triggered buffer setup failed\n");
441		return ret;
442	}
443
444	ret = devm_iio_device_register(dev, indio_dev);
445	if (ret < 0) {
446		dev_err(dev, "unable to register iio device\n");
447		return ret;
448	}
449
450	return 0;
451}
452EXPORT_SYMBOL_NS(ms5611_probe, IIO_MS5611);
453
454MODULE_AUTHOR("Tomasz Duszynski <tduszyns@gmail.com>");
455MODULE_DESCRIPTION("MS5611 core driver");
456MODULE_LICENSE("GPL v2");
457