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iio: pressure: add support for MS5611 pressure and temperature sensor
Add support for Measurement Specialities MS5611 pressure and temperature sensor. Signed-off-by: Tomasz Duszynski <[email protected]> Signed-off-by: Jonathan Cameron <[email protected]>
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‎drivers/iio/pressure/Kconfig

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@@ -52,6 +52,33 @@ config MPL3115
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To compile this driver as a module, choose M here: the module
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will be called mpl3115.
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config MS5611
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tristate "Measurement Specialities MS5611 pressure sensor driver"
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help
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Say Y here to build support for the Measurement Specialities
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MS5611 pressure and temperature sensor.
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To compile this driver as a module, choose M here: the module will
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be called ms5611_core.
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config MS5611_I2C
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tristate "support I2C bus connection"
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depends on I2C && MS5611
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help
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Say Y here to build I2C bus support for MS5611.
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To compile this driver as a module, choose M here: the module will
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be called ms5611_i2c.
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config MS5611_SPI
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tristate "support SPI bus connection"
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depends on SPI_MASTER && MS5611
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help
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Say Y here to build SPI bus support for MS5611.
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To compile this driver as a module, choose M here: the module will
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be called ms5611_spi.
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config IIO_ST_PRESS
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tristate "STMicroelectronics pressure sensor Driver"
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depends on (I2C || SPI_MASTER) && SYSFS

‎drivers/iio/pressure/Makefile

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@@ -7,6 +7,9 @@ obj-$(CONFIG_BMP280) += bmp280.o
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obj-$(CONFIG_HID_SENSOR_PRESS) += hid-sensor-press.o
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obj-$(CONFIG_MPL115) += mpl115.o
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obj-$(CONFIG_MPL3115) += mpl3115.o
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obj-$(CONFIG_MS5611) += ms5611_core.o
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obj-$(CONFIG_MS5611_I2C) += ms5611_i2c.o
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obj-$(CONFIG_MS5611_SPI) += ms5611_spi.o
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obj-$(CONFIG_IIO_ST_PRESS) += st_pressure.o
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st_pressure-y := st_pressure_core.o
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st_pressure-$(CONFIG_IIO_BUFFER) += st_pressure_buffer.o

‎drivers/iio/pressure/ms5611.h

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/*
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* MS5611 pressure and temperature sensor driver
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*
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* Copyright (c) Tomasz Duszynski <[email protected]>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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*/
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#ifndef _MS5611_H
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#define _MS5611_H
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#include <linux/device.h>
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#include <linux/iio/iio.h>
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#include <linux/mutex.h>
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#define MS5611_RESET 0x1e
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#define MS5611_READ_ADC 0x00
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#define MS5611_READ_PROM_WORD 0xA0
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#define MS5611_START_TEMP_CONV 0x58
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#define MS5611_START_PRESSURE_CONV 0x48
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#define MS5611_CONV_TIME_MIN 9040
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#define MS5611_CONV_TIME_MAX 10000
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#define MS5611_PROM_WORDS_NB 8
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struct ms5611_state {
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void *client;
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struct mutex lock;
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int (*reset)(struct device *dev);
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int (*read_prom_word)(struct device *dev, int index, u16 *word);
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int (*read_adc_temp_and_pressure)(struct device *dev,
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s32 *temp, s32 *pressure);
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u16 prom[MS5611_PROM_WORDS_NB];
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};
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int ms5611_probe(struct iio_dev *indio_dev, struct device *dev);
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#endif /* _MS5611_H */

‎drivers/iio/pressure/ms5611_core.c

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

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