2 * MS5611 pressure and temperature sensor driver
4 * Copyright (c) Tomasz Duszynski <tduszyns@gmail.com>
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
11 * http://www.meas-spec.com/downloads/MS5611-01BA03.pdf
15 #include <linux/module.h>
16 #include <linux/iio/iio.h>
17 #include <linux/delay.h>
21 static bool ms5611_prom_is_valid(u16 *prom, size_t len)
24 uint16_t crc = 0, crc_orig = prom[7] & 0x000F;
28 for (i = 0; i < len * 2; i++) {
30 crc ^= prom[i >> 1] & 0x00FF;
32 crc ^= prom[i >> 1] >> 8;
34 for (j = 0; j < 8; j++) {
36 crc = (crc << 1) ^ 0x3000;
42 crc = (crc >> 12) & 0x000F;
44 return crc_orig != 0x0000 && crc == crc_orig;
47 static int ms5611_read_prom(struct iio_dev *indio_dev)
50 struct ms5611_state *st = iio_priv(indio_dev);
52 for (i = 0; i < MS5611_PROM_WORDS_NB; i++) {
53 ret = st->read_prom_word(&indio_dev->dev, i, &st->prom[i]);
55 dev_err(&indio_dev->dev,
56 "failed to read prom at %d\n", i);
61 if (!ms5611_prom_is_valid(st->prom, MS5611_PROM_WORDS_NB)) {
62 dev_err(&indio_dev->dev, "PROM integrity check failed\n");
69 static int ms5611_read_temp_and_pressure(struct iio_dev *indio_dev,
70 s32 *temp, s32 *pressure)
75 struct ms5611_state *st = iio_priv(indio_dev);
77 ret = st->read_adc_temp_and_pressure(&indio_dev->dev, &t, &p);
79 dev_err(&indio_dev->dev,
80 "failed to read temperature and pressure\n");
84 dt = t - (st->prom[5] << 8);
85 off = ((s64)st->prom[2] << 16) + ((st->prom[4] * dt) >> 7);
86 sens = ((s64)st->prom[1] << 15) + ((st->prom[3] * dt) >> 8);
88 t = 2000 + ((st->prom[6] * dt) >> 23);
93 off2 = (5 * (t - 2000) * (t - 2000)) >> 1;
97 s64 tmp = (t + 1500) * (t + 1500);
100 sens2 += (11 * tmp) >> 1;
109 *pressure = (((p * sens) >> 21) - off) >> 15;
114 static int ms5611_reset(struct iio_dev *indio_dev)
117 struct ms5611_state *st = iio_priv(indio_dev);
119 ret = st->reset(&indio_dev->dev);
121 dev_err(&indio_dev->dev, "failed to reset device\n");
125 usleep_range(3000, 4000);
130 static int ms5611_read_raw(struct iio_dev *indio_dev,
131 struct iio_chan_spec const *chan,
132 int *val, int *val2, long mask)
136 struct ms5611_state *st = iio_priv(indio_dev);
139 case IIO_CHAN_INFO_PROCESSED:
140 mutex_lock(&st->lock);
141 ret = ms5611_read_temp_and_pressure(indio_dev,
143 mutex_unlock(&st->lock);
147 switch (chan->type) {
152 *val = pressure / 1000;
153 *val2 = (pressure % 1000) * 1000;
154 return IIO_VAL_INT_PLUS_MICRO;
163 static const struct iio_chan_spec ms5611_channels[] = {
165 .type = IIO_PRESSURE,
166 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
167 BIT(IIO_CHAN_INFO_SCALE)
171 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
172 BIT(IIO_CHAN_INFO_SCALE)
176 static const struct iio_info ms5611_info = {
177 .read_raw = &ms5611_read_raw,
178 .driver_module = THIS_MODULE,
181 static int ms5611_init(struct iio_dev *indio_dev)
185 ret = ms5611_reset(indio_dev);
189 return ms5611_read_prom(indio_dev);
192 int ms5611_probe(struct iio_dev *indio_dev, struct device *dev)
195 struct ms5611_state *st = iio_priv(indio_dev);
197 mutex_init(&st->lock);
198 indio_dev->dev.parent = dev;
199 indio_dev->name = dev->driver->name;
200 indio_dev->info = &ms5611_info;
201 indio_dev->channels = ms5611_channels;
202 indio_dev->num_channels = ARRAY_SIZE(ms5611_channels);
203 indio_dev->modes = INDIO_DIRECT_MODE;
205 ret = ms5611_init(indio_dev);
209 return devm_iio_device_register(dev, indio_dev);
211 EXPORT_SYMBOL(ms5611_probe);
213 MODULE_AUTHOR("Tomasz Duszynski <tduszyns@gmail.com>");
214 MODULE_DESCRIPTION("MS5611 core driver");
215 MODULE_LICENSE("GPL v2");