ms5611_core.c

  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		aligned_s64 ts;
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
312	if (mask != IIO_CHAN_INFO_OVERSAMPLING_RATIO)
313		return -EINVAL;
314
315	if (chan->type == IIO_TEMP)
316		osr = ms5611_find_osr(val, ms5611_avail_temp_osr,
317				      ARRAY_SIZE(ms5611_avail_temp_osr));
318	else if (chan->type == IIO_PRESSURE)
319		osr = ms5611_find_osr(val, ms5611_avail_pressure_osr,
320				      ARRAY_SIZE(ms5611_avail_pressure_osr));
321	if (!osr)
322		return -EINVAL;
323
324	if (!iio_device_claim_direct(indio_dev))
325		return -EBUSY;
326
327	mutex_lock(&st->lock);
328
329	if (chan->type == IIO_TEMP)
330		st->temp_osr = osr;
331	else
332		st->pressure_osr = osr;
333
334	mutex_unlock(&st->lock);
335	iio_device_release_direct(indio_dev);
336
337	return 0;
338}
339
340static const unsigned long ms5611_scan_masks[] = {0x3, 0};
341
342static const struct iio_chan_spec ms5611_channels[] = {
343	{
344		.type = IIO_PRESSURE,
345		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
346			BIT(IIO_CHAN_INFO_SCALE) |
347			BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
348		.scan_index = 0,
349		.scan_type = {
350			.sign = 's',
351			.realbits = 32,
352			.storagebits = 32,
353			.endianness = IIO_CPU,
354		},
355	},
356	{
357		.type = IIO_TEMP,
358		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
359			BIT(IIO_CHAN_INFO_SCALE) |
360			BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
361		.scan_index = 1,
362		.scan_type = {
363			.sign = 's',
364			.realbits = 32,
365			.storagebits = 32,
366			.endianness = IIO_CPU,
367		},
368	},
369	IIO_CHAN_SOFT_TIMESTAMP(2),
370};
371
372static const struct iio_info ms5611_info = {
373	.read_raw = &ms5611_read_raw,
374	.write_raw = &ms5611_write_raw,
375	.attrs = &ms5611_attribute_group,
376};
377
378static int ms5611_init(struct iio_dev *indio_dev)
379{
380	int ret;
381
382	/* Enable attached regulator if any. */
383	ret = devm_regulator_get_enable(indio_dev->dev.parent, "vdd");
384	if (ret)
385		return ret;
386
387	ret = ms5611_reset(indio_dev);
388	if (ret < 0)
389		return ret;
390
391	ret = ms5611_read_prom(indio_dev);
392	if (ret < 0)
393		return ret;
394
395	return 0;
396}
397
398int ms5611_probe(struct iio_dev *indio_dev, struct device *dev,
399		 const char *name, int type)
400{
401	int ret;
402	struct ms5611_state *st = iio_priv(indio_dev);
403
404	mutex_init(&st->lock);
405
406	switch (type) {
407	case MS5611:
408		st->compensate_temp_and_pressure =
409			ms5611_temp_and_pressure_compensate;
410		break;
411	case MS5607:
412		st->compensate_temp_and_pressure =
413			ms5607_temp_and_pressure_compensate;
414		break;
415	default:
416		return -EINVAL;
417	}
418
419	st->temp_osr =
420		&ms5611_avail_temp_osr[ARRAY_SIZE(ms5611_avail_temp_osr) - 1];
421	st->pressure_osr =
422		&ms5611_avail_pressure_osr[ARRAY_SIZE(ms5611_avail_pressure_osr)
423					   - 1];
424	indio_dev->name = name;
425	indio_dev->info = &ms5611_info;
426	indio_dev->channels = ms5611_channels;
427	indio_dev->num_channels = ARRAY_SIZE(ms5611_channels);
428	indio_dev->modes = INDIO_DIRECT_MODE;
429	indio_dev->available_scan_masks = ms5611_scan_masks;
430
431	ret = ms5611_init(indio_dev);
432	if (ret < 0)
433		return ret;
434
435	ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL,
436					 ms5611_trigger_handler, NULL);
437	if (ret < 0) {
438		dev_err(dev, "iio triggered buffer setup failed\n");
439		return ret;
440	}
441
442	ret = devm_iio_device_register(dev, indio_dev);
443	if (ret < 0) {
444		dev_err(dev, "unable to register iio device\n");
445		return ret;
446	}
447
448	return 0;
449}
450EXPORT_SYMBOL_NS(ms5611_probe, "IIO_MS5611");
451
452MODULE_AUTHOR("Tomasz Duszynski <tduszyns@gmail.com>");
453MODULE_DESCRIPTION("MS5611 core driver");
454MODULE_LICENSE("GPL v2");