159 lines
3.5 KiB
C
159 lines
3.5 KiB
C
/*
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* Copyright (c) 2020 Laird Connectivity
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* Copyright (c) 2019 Electronut Labs
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#define DT_DRV_COMPAT silabs_si7055
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#include <zephyr/drivers/sensor.h>
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#include <zephyr/kernel.h>
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#include <zephyr/device.h>
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#include <zephyr/logging/log.h>
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#include <zephyr/drivers/i2c.h>
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#include "si7055.h"
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#if CONFIG_SI7055_ENABLE_CHECKSUM
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#include <zephyr/sys/crc.h>
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#endif
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LOG_MODULE_REGISTER(si7055, CONFIG_SENSOR_LOG_LEVEL);
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struct si7055_data {
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uint16_t temperature;
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};
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struct si7055_config {
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struct i2c_dt_spec i2c;
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};
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/**
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* @brief function to get temperature
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*
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* @return int 0 on success
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* -EIO for I/O and checksum errors
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*/
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static int si7055_get_temperature(const struct device *dev)
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{
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struct si7055_data *si_data = dev->data;
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const struct si7055_config *config = dev->config;
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int retval;
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#if CONFIG_SI7055_ENABLE_CHECKSUM
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uint8_t temp[SI7055_TEMPERATURE_READ_WITH_CHECKSUM_SIZE];
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#else
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uint8_t temp[SI7055_TEMPERATURE_READ_NO_CHECKSUM_SIZE];
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#endif
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retval = i2c_burst_read_dt(&config->i2c, SI7055_MEAS_TEMP_MASTER_MODE,
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temp, sizeof(temp));
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/* Refer to
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* https://www.silabs.com/documents/public/data-sheets/Si7050-1-3-4-5-A20.pdf
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*/
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if (retval == 0) {
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#if CONFIG_SI7055_ENABLE_CHECKSUM
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if (crc8(temp, SI7055_DATA_SIZE, SI7055_CRC_POLY,
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SI7055_CRC_INIT, false) != temp[SI7055_DATA_SIZE]){
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LOG_ERR("checksum failed.\n");
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return(-EIO);
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}
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#endif
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si_data->temperature = (temp[SI7055_TEMPERATURE_DATA_BYTE_0]
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<< 8) |
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temp[SI7055_TEMPERATURE_DATA_BYTE_1];
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} else {
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LOG_ERR("read register err");
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}
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return retval;
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}
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/**
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* @brief fetch a sample from the sensor
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*
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* @return 0
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*/
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static int si7055_sample_fetch(const struct device *dev,
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enum sensor_channel chan)
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{
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int retval;
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retval = si7055_get_temperature(dev);
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return retval;
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}
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/**
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* @brief sensor value get
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*
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* @return -ENOTSUP for unsupported channels
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*/
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static int si7055_channel_get(const struct device *dev,
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enum sensor_channel chan,
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struct sensor_value *val)
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{
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struct si7055_data *si_data = dev->data;
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/* Refer to
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* https://www.silabs.com/documents/public/data-sheets/Si7050-1-3-4-5-A20.pdf
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*/
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if (chan == SENSOR_CHAN_AMBIENT_TEMP) {
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int32_t temp_ucelcius = (((SI7055_CONV_FACTOR_1 *
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(int32_t)si_data->temperature) /
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(__UINT16_MAX__ + 1)) -
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SI7055_CONV_FACTOR_2) *
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SI7055_MULTIPLIER;
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val->val1 = temp_ucelcius / SI7055_DIVIDER;
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val->val2 = temp_ucelcius % SI7055_DIVIDER;
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LOG_DBG("temperature = val1:%d, val2:%d",
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val->val1, val->val2);
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return 0;
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} else {
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return -ENOTSUP;
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}
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}
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static const struct sensor_driver_api si7055_api = {
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.sample_fetch = &si7055_sample_fetch,
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.channel_get = &si7055_channel_get,
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};
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/**
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* @brief initialize the sensor
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*
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* @return 0 for success
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*/
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static int si7055_init(const struct device *dev)
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{
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const struct si7055_config *config = dev->config;
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if (!device_is_ready(config->i2c.bus)) {
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LOG_ERR("Bus device is not ready");
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return -ENODEV;
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}
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LOG_DBG("si7055 init ok");
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return 0;
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}
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#define SI7055_DEFINE(inst) \
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static struct si7055_data si7055_data_##inst; \
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\
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static const struct si7055_config si7055_config_##inst = { \
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.i2c = I2C_DT_SPEC_INST_GET(inst), \
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}; \
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\
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DEVICE_DT_INST_DEFINE(inst, si7055_init, NULL, \
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&si7055_data_##inst, &si7055_config_##inst, POST_KERNEL, \
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CONFIG_SENSOR_INIT_PRIORITY, &si7055_api); \
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DT_INST_FOREACH_STATUS_OKAY(SI7055_DEFINE)
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