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033691a9a1
Add support for setting and retrieving OverSampling Rate independently for each of the temperature and pressure channels. This allows userspace to fine tune hardware sampling process according to the following tradeoffs : * the higher the OSR, the finer the resolution ; * the higher the OSR, the lower the noise ; BUT: * the higher the OSR, the larger the drift ; * the higher the OSR, the longer the response time, i.e. less samples per unit of time. Signed-off-by: Gregor Boirie <gregor.boirie@parrot.com> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
469 lines
11 KiB
C
469 lines
11 KiB
C
/*
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* MS5611 pressure and temperature sensor driver
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*
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* Copyright (c) Tomasz Duszynski <tduszyns@gmail.com>
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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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* http://www.meas-spec.com/downloads/MS5607-02BA03.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 <linux/regulator/consumer.h>
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#include <linux/iio/sysfs.h>
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#include <linux/iio/buffer.h>
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#include <linux/iio/triggered_buffer.h>
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#include <linux/iio/trigger_consumer.h>
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#include "ms5611.h"
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#define MS5611_INIT_OSR(_cmd, _conv_usec, _rate) \
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{ .cmd = _cmd, .conv_usec = _conv_usec, .rate = _rate }
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static const struct ms5611_osr ms5611_avail_pressure_osr[] = {
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MS5611_INIT_OSR(0x40, 600, 256),
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MS5611_INIT_OSR(0x42, 1170, 512),
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MS5611_INIT_OSR(0x44, 2280, 1024),
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MS5611_INIT_OSR(0x46, 4540, 2048),
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MS5611_INIT_OSR(0x48, 9040, 4096)
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};
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static const struct ms5611_osr ms5611_avail_temp_osr[] = {
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MS5611_INIT_OSR(0x50, 600, 256),
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MS5611_INIT_OSR(0x52, 1170, 512),
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MS5611_INIT_OSR(0x54, 2280, 1024),
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MS5611_INIT_OSR(0x56, 4540, 2048),
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MS5611_INIT_OSR(0x58, 9040, 4096)
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};
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static const char ms5611_show_osr[] = "256 512 1024 2048 4096";
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static IIO_CONST_ATTR(oversampling_ratio_available, ms5611_show_osr);
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static struct attribute *ms5611_attributes[] = {
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&iio_const_attr_oversampling_ratio_available.dev_attr.attr,
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NULL,
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};
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static const struct attribute_group ms5611_attribute_group = {
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.attrs = ms5611_attributes,
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};
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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,
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i, &st->chip_info->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->chip_info->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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struct ms5611_state *st = iio_priv(indio_dev);
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ret = st->read_adc_temp_and_pressure(&indio_dev->dev, temp, pressure);
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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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return st->chip_info->temp_and_pressure_compensate(st->chip_info,
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temp, pressure);
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}
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static int ms5611_temp_and_pressure_compensate(struct ms5611_chip_info *chip_info,
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s32 *temp, s32 *pressure)
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{
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s32 t = *temp, p = *pressure;
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s64 off, sens, dt;
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dt = t - (chip_info->prom[5] << 8);
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off = ((s64)chip_info->prom[2] << 16) + ((chip_info->prom[4] * dt) >> 7);
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sens = ((s64)chip_info->prom[1] << 15) + ((chip_info->prom[3] * dt) >> 8);
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t = 2000 + ((chip_info->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 ms5607_temp_and_pressure_compensate(struct ms5611_chip_info *chip_info,
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s32 *temp, s32 *pressure)
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{
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s32 t = *temp, p = *pressure;
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s64 off, sens, dt;
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dt = t - (chip_info->prom[5] << 8);
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off = ((s64)chip_info->prom[2] << 17) + ((chip_info->prom[4] * dt) >> 6);
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sens = ((s64)chip_info->prom[1] << 16) + ((chip_info->prom[3] * dt) >> 7);
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t = 2000 + ((chip_info->prom[6] * dt) >> 23);
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if (t < 2000) {
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s64 off2, sens2, t2, tmp;
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t2 = (dt * dt) >> 31;
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tmp = (t - 2000) * (t - 2000);
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off2 = (61 * tmp) >> 4;
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sens2 = tmp << 1;
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if (t < -1500) {
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tmp = (t + 1500) * (t + 1500);
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off2 += 15 * tmp;
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sens2 += 8 * tmp;
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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 irqreturn_t ms5611_trigger_handler(int irq, void *p)
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{
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struct iio_poll_func *pf = p;
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struct iio_dev *indio_dev = pf->indio_dev;
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struct ms5611_state *st = iio_priv(indio_dev);
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s32 buf[4]; /* s32 (pressure) + s32 (temp) + 2 * s32 (timestamp) */
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int ret;
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mutex_lock(&st->lock);
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ret = ms5611_read_temp_and_pressure(indio_dev, &buf[1], &buf[0]);
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mutex_unlock(&st->lock);
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if (ret < 0)
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goto err;
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iio_push_to_buffers_with_timestamp(indio_dev, buf, iio_get_time_ns());
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err:
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iio_trigger_notify_done(indio_dev->trig);
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return IRQ_HANDLED;
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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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case IIO_CHAN_INFO_SCALE:
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switch (chan->type) {
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case IIO_TEMP:
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*val = 10;
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return IIO_VAL_INT;
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case IIO_PRESSURE:
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*val = 0;
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*val2 = 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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case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
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if (chan->type != IIO_TEMP && chan->type != IIO_PRESSURE)
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break;
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mutex_lock(&st->lock);
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if (chan->type == IIO_TEMP)
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*val = (int)st->temp_osr->rate;
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else
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*val = (int)st->pressure_osr->rate;
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mutex_unlock(&st->lock);
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return IIO_VAL_INT;
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}
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return -EINVAL;
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}
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static const struct ms5611_osr *ms5611_find_osr(int rate,
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const struct ms5611_osr *osr,
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size_t count)
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{
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unsigned int r;
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for (r = 0; r < count; r++)
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if ((unsigned short)rate == osr[r].rate)
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break;
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if (r >= count)
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return NULL;
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return &osr[r];
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}
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static int ms5611_write_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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struct ms5611_state *st = iio_priv(indio_dev);
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const struct ms5611_osr *osr = NULL;
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if (mask != IIO_CHAN_INFO_OVERSAMPLING_RATIO)
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return -EINVAL;
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if (chan->type == IIO_TEMP)
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osr = ms5611_find_osr(val, ms5611_avail_temp_osr,
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ARRAY_SIZE(ms5611_avail_temp_osr));
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else if (chan->type == IIO_PRESSURE)
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osr = ms5611_find_osr(val, ms5611_avail_pressure_osr,
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ARRAY_SIZE(ms5611_avail_pressure_osr));
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if (!osr)
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return -EINVAL;
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mutex_lock(&st->lock);
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if (iio_buffer_enabled(indio_dev)) {
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mutex_unlock(&st->lock);
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return -EBUSY;
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}
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if (chan->type == IIO_TEMP)
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st->temp_osr = osr;
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else
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st->pressure_osr = osr;
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mutex_unlock(&st->lock);
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return 0;
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}
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static const unsigned long ms5611_scan_masks[] = {0x3, 0};
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static struct ms5611_chip_info chip_info_tbl[] = {
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[MS5611] = {
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.temp_and_pressure_compensate = ms5611_temp_and_pressure_compensate,
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},
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[MS5607] = {
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.temp_and_pressure_compensate = ms5607_temp_and_pressure_compensate,
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}
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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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BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
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.scan_index = 0,
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.scan_type = {
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.sign = 's',
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.realbits = 32,
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.storagebits = 32,
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.endianness = IIO_CPU,
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},
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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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BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
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.scan_index = 1,
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.scan_type = {
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.sign = 's',
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.realbits = 32,
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.storagebits = 32,
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.endianness = IIO_CPU,
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},
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},
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IIO_CHAN_SOFT_TIMESTAMP(2),
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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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.write_raw = &ms5611_write_raw,
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.attrs = &ms5611_attribute_group,
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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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struct regulator *vdd = devm_regulator_get(indio_dev->dev.parent,
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"vdd");
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/* Enable attached regulator if any. */
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if (!IS_ERR(vdd)) {
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ret = regulator_enable(vdd);
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if (ret) {
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dev_err(indio_dev->dev.parent,
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"failed to enable Vdd supply: %d\n", ret);
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return ret;
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}
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}
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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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const char *name, int type)
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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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st->chip_info = &chip_info_tbl[type];
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st->temp_osr =
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&ms5611_avail_temp_osr[ARRAY_SIZE(ms5611_avail_temp_osr) - 1];
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st->pressure_osr =
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&ms5611_avail_pressure_osr[ARRAY_SIZE(ms5611_avail_pressure_osr)
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- 1];
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indio_dev->dev.parent = dev;
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indio_dev->name = 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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indio_dev->available_scan_masks = ms5611_scan_masks;
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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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ret = iio_triggered_buffer_setup(indio_dev, NULL,
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ms5611_trigger_handler, NULL);
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if (ret < 0) {
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dev_err(dev, "iio triggered buffer setup failed\n");
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return ret;
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}
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ret = iio_device_register(indio_dev);
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if (ret < 0) {
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dev_err(dev, "unable to register iio device\n");
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goto err_buffer_cleanup;
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}
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return 0;
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err_buffer_cleanup:
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iio_triggered_buffer_cleanup(indio_dev);
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return ret;
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}
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EXPORT_SYMBOL(ms5611_probe);
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int ms5611_remove(struct iio_dev *indio_dev)
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{
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iio_device_unregister(indio_dev);
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iio_triggered_buffer_cleanup(indio_dev);
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return 0;
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}
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EXPORT_SYMBOL(ms5611_remove);
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MODULE_AUTHOR("Tomasz Duszynski <tduszyns@gmail.com>");
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MODULE_DESCRIPTION("MS5611 core driver");
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MODULE_LICENSE("GPL v2");
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