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* MS5611 pressure and temperature sensor driver
*
* Copyright (c) Tomasz Duszynski <tduszyns@gmail.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* Data sheet:
* http://www.meas-spec.com/downloads/MS5611-01BA03.pdf
* http://www.meas-spec.com/downloads/MS5607-02BA03.pdf
*
*/
#include <linux/module.h>
#include <linux/iio/iio.h>
#include <linux/delay.h>
#include "ms5611.h"
static bool ms5611_prom_is_valid(u16 *prom, size_t len)
{
int i, j;
uint16_t crc = 0, crc_orig = prom[7] & 0x000F;
prom[7] &= 0xFF00;
for (i = 0; i < len * 2; i++) {
if (i % 2 == 1)
crc ^= prom[i >> 1] & 0x00FF;
else
crc ^= prom[i >> 1] >> 8;
for (j = 0; j < 8; j++) {
if (crc & 0x8000)
crc = (crc << 1) ^ 0x3000;
else
crc <<= 1;
}
}
crc = (crc >> 12) & 0x000F;
return crc_orig != 0x0000 && crc == crc_orig;
}
static int ms5611_read_prom(struct iio_dev *indio_dev)
{
int ret, i;
struct ms5611_state *st = iio_priv(indio_dev);
for (i = 0; i < MS5611_PROM_WORDS_NB; i++) {
ret = st->read_prom_word(&indio_dev->dev,
i, &st->chip_info->prom[i]);
if (ret < 0) {
dev_err(&indio_dev->dev,
"failed to read prom at %d\n", i);
return ret;
}
}
if (!ms5611_prom_is_valid(st->chip_info->prom, MS5611_PROM_WORDS_NB)) {
dev_err(&indio_dev->dev, "PROM integrity check failed\n");
return -ENODEV;
}
return 0;
}
static int ms5611_read_temp_and_pressure(struct iio_dev *indio_dev,
s32 *temp, s32 *pressure)
{
int ret;
struct ms5611_state *st = iio_priv(indio_dev);
ret = st->read_adc_temp_and_pressure(&indio_dev->dev, temp, pressure);
if (ret < 0) {
dev_err(&indio_dev->dev,
"failed to read temperature and pressure\n");
return ret;
}
return st->chip_info->temp_and_pressure_compensate(st->chip_info,
temp, pressure);
}
static int ms5611_temp_and_pressure_compensate(struct ms5611_chip_info *chip_info,
s32 *temp, s32 *pressure)
{
s32 t = *temp, p = *pressure;
s64 off, sens, dt;
dt = t - (chip_info->prom[5] << 8);
off = ((s64)chip_info->prom[2] << 16) + ((chip_info->prom[4] * dt) >> 7);
sens = ((s64)chip_info->prom[1] << 15) + ((chip_info->prom[3] * dt) >> 8);
t = 2000 + ((chip_info->prom[6] * dt) >> 23);
if (t < 2000) {
s64 off2, sens2, t2;
t2 = (dt * dt) >> 31;
off2 = (5 * (t - 2000) * (t - 2000)) >> 1;
sens2 = off2 >> 1;
if (t < -1500) {
s64 tmp = (t + 1500) * (t + 1500);
off2 += 7 * tmp;
sens2 += (11 * tmp) >> 1;
}
t -= t2;
off -= off2;
sens -= sens2;
}
*temp = t;
*pressure = (((p * sens) >> 21) - off) >> 15;
return 0;
}
static int ms5607_temp_and_pressure_compensate(struct ms5611_chip_info *chip_info,
s32 *temp, s32 *pressure)
{
s32 t = *temp, p = *pressure;
s64 off, sens, dt;
dt = t - (chip_info->prom[5] << 8);
off = ((s64)chip_info->prom[2] << 17) + ((chip_info->prom[4] * dt) >> 6);
sens = ((s64)chip_info->prom[1] << 16) + ((chip_info->prom[3] * dt) >> 7);
t = 2000 + ((chip_info->prom[6] * dt) >> 23);
if (t < 2000) {
s64 off2, sens2, t2;
t2 = (dt * dt) >> 31;
off2 = (61 * (t - 2000) * (t - 2000)) >> 4;
sens2 = off2 << 1;
if (t < -1500) {
s64 tmp = (t + 1500) * (t + 1500);
off2 += 15 * tmp;
sens2 += (8 * tmp);
}
t -= t2;
off -= off2;
sens -= sens2;
}
*temp = t;
*pressure = (((p * sens) >> 21) - off) >> 15;
return 0;
}
static int ms5611_reset(struct iio_dev *indio_dev)
{
int ret;
struct ms5611_state *st = iio_priv(indio_dev);
ret = st->reset(&indio_dev->dev);
if (ret < 0) {
dev_err(&indio_dev->dev, "failed to reset device\n");
return ret;
}
usleep_range(3000, 4000);
return 0;
}
static int ms5611_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
{
int ret;
s32 temp, pressure;
struct ms5611_state *st = iio_priv(indio_dev);
switch (mask) {
case IIO_CHAN_INFO_PROCESSED:
mutex_lock(&st->lock);
ret = ms5611_read_temp_and_pressure(indio_dev,
&temp, &pressure);
mutex_unlock(&st->lock);
if (ret < 0)
return ret;
switch (chan->type) {
case IIO_TEMP:
*val = temp * 10;
return IIO_VAL_INT;
case IIO_PRESSURE:
*val = pressure / 1000;
*val2 = (pressure % 1000) * 1000;
return IIO_VAL_INT_PLUS_MICRO;
default:
return -EINVAL;
}
}
return -EINVAL;
}
static struct ms5611_chip_info chip_info_tbl[] = {
[MS5611] = {
.temp_and_pressure_compensate = ms5611_temp_and_pressure_compensate,
},
[MS5607] = {
.temp_and_pressure_compensate = ms5607_temp_and_pressure_compensate,
}
};
static const struct iio_chan_spec ms5611_channels[] = {
{
.type = IIO_PRESSURE,
.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
},
{
.type = IIO_TEMP,
.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
}
};
static const struct iio_info ms5611_info = {
.read_raw = &ms5611_read_raw,
.driver_module = THIS_MODULE,
};
static int ms5611_init(struct iio_dev *indio_dev)
{
int ret;
ret = ms5611_reset(indio_dev);
if (ret < 0)
return ret;
return ms5611_read_prom(indio_dev);
}
int ms5611_probe(struct iio_dev *indio_dev, struct device *dev, int type)
{
int ret;
struct ms5611_state *st = iio_priv(indio_dev);
mutex_init(&st->lock);
st->chip_info = &chip_info_tbl[type];
indio_dev->dev.parent = dev;
indio_dev->name = dev->driver->name;
indio_dev->info = &ms5611_info;
indio_dev->channels = ms5611_channels;
indio_dev->num_channels = ARRAY_SIZE(ms5611_channels);
indio_dev->modes = INDIO_DIRECT_MODE;
ret = ms5611_init(indio_dev);
if (ret < 0)
return ret;
return devm_iio_device_register(dev, indio_dev);
}
EXPORT_SYMBOL(ms5611_probe);
MODULE_AUTHOR("Tomasz Duszynski <tduszyns@gmail.com>");
MODULE_DESCRIPTION("MS5611 core driver");
MODULE_LICENSE("GPL v2");
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