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drivers: sensor: shtcx: add driver supporting shtc1 and shtc3
Add driver for sensirion consumer humidity sensor line. Supports shtc1 and shtc3, but only shtc3 is tested. Signed-off-by: Thomas Stranger <[email protected]>
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‎drivers/sensor/CMakeLists.txt

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@@ -69,6 +69,7 @@ add_subdirectory_ifdef(CONFIG_QDEC_NRFX qdec_nrfx)
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add_subdirectory_ifdef(CONFIG_QDEC_SAM qdec_sam)
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add_subdirectory_ifdef(CONFIG_TEMP_NRF5 nrf5)
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add_subdirectory_ifdef(CONFIG_SBS_GAUGE sbs_gauge)
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add_subdirectory_ifdef(CONFIG_SHTCX shtcx)
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add_subdirectory_ifdef(CONFIG_SHT3XD sht3xd)
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add_subdirectory_ifdef(CONFIG_SI7006 si7006)
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add_subdirectory_ifdef(CONFIG_SI7055 si7055)

‎drivers/sensor/Kconfig

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@@ -178,6 +178,8 @@ source "drivers/sensor/qdec_sam/Kconfig"
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source "drivers/sensor/sbs_gauge/Kconfig"
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source "drivers/sensor/shtcx/Kconfig"
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source "drivers/sensor/sht3xd/Kconfig"
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source "drivers/sensor/si7006/Kconfig"

‎drivers/sensor/shtcx/CMakeLists.txt

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# SPDX-License-Identifier: Apache-2.0
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zephyr_library()
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zephyr_library_sources_ifdef(CONFIG_SHTCX shtcx.c)

‎drivers/sensor/shtcx/Kconfig

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# SHTCX temperature and humidity sensor configuration options
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# Copyright (c) 2021 Thomas Stranger
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# SPDX-License-Identifier: Apache-2.0
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config SHTCX
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bool "SHTCX: SHTC1 and SHTC3 Temperature and Humidity Sensor"
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depends on I2C
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help
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Enable driver for SHTC1 and SHTC3 temperature and humidity sensors.

‎drivers/sensor/shtcx/shtcx.c

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/*
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* Copyright (c) 2021 Thomas Stranger
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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 sensirion_shtcx
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#include <device.h>
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#include <drivers/i2c.h>
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#include <kernel.h>
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#include <drivers/sensor.h>
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#include <sys/__assert.h>
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#include <sys/byteorder.h>
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#include <sys/crc.h>
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#include <logging/log.h>
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#include "shtcx.h"
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LOG_MODULE_REGISTER(SHTCX, CONFIG_SENSOR_LOG_LEVEL);
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/* all cmds read temp first: cmd[MEASURE_MODE][Clock_stretching_enabled] */
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static const uint16_t measure_cmd[2][2] = {
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{ 0x7866, 0x7CA2 },
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{ 0x609C, 0x6458 },
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};
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/* measure_wait_us[shtcx_chip][MEASURE_MODE] */
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static const uint16_t measure_wait_us[2][2] = {
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/* shtc3: 12.1ms, 0.8ms */
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{ 1210, 800 }, /* shtc3 */
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/* shtc1: 14.4ms, 0.94ms */
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{ 14400, 940 }, /* shtc1 */
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};
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/*
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* CRC algorithm parameters were taken from the
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* "Checksum Calculation" section of the datasheet.
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*/
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static uint8_t shtcx_compute_crc(uint16_t value)
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{
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uint8_t buf[2];
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sys_put_be16(value, buf);
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return crc8(buf, 2, 0x31, 0xFF, false);
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}
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/* val = -45 + 175 * sample / (2^16) */
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static void shtcx_temperature_from_raw(uint16_t raw, struct sensor_value *val)
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{
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int32_t tmp;
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tmp = (int32_t)raw * 175U - (45 << 16);
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val->val1 = tmp / 0x10000;
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/* x * 1.000.000 / 65.536 == x * 15625 / 2^10 */
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val->val2 = ((tmp % 0x10000) * 15625U) / 1024;
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}
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/* val = 100 * sample / (2^16) */
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static void shtcx_humidity_from_raw(uint16_t raw, struct sensor_value *val)
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{
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uint32_t tmp;
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tmp = (uint32_t)raw * 100U;
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val->val1 = tmp / 0x10000;
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/* x * 1.000.000 / 65.536 == x * 15625 / 1024 */
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val->val2 = (tmp % 0x10000) * 15625U / 1024;
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}
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static int shtcx_write_command(const struct device *dev, uint16_t cmd)
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{
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uint8_t tx_buf[2];
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sys_put_be16(cmd, tx_buf);
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return i2c_write(shtcx_i2c_bus(dev), tx_buf, sizeof(tx_buf),
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shtcx_i2c_address(dev));
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}
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static int shtcx_read_words(const struct device *dev, uint16_t cmd, uint16_t *data,
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uint16_t num_words, uint16_t max_duration_us)
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{
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const struct shtcx_config *cfg = dev->config;
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int status = 0;
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uint32_t raw_len = num_words * (SHTCX_WORD_LEN + SHTCX_CRC8_LEN);
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uint16_t temp16;
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uint8_t rx_buf[SHTCX_MAX_READ_LEN];
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int dst = 0;
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status = shtcx_write_command(dev, cmd);
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if (status != 0) {
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LOG_DBG("Failed to initiate read");
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return -EIO;
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}
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if (!cfg->clock_stretching) {
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k_sleep(K_USEC(max_duration_us));
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}
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status = i2c_read(shtcx_i2c_bus(dev), rx_buf, raw_len,
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shtcx_i2c_address(dev));
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if (status != 0) {
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LOG_DBG("Failed to read data");
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return -EIO;
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}
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for (int i = 0; i < raw_len; i += (SHTCX_WORD_LEN + SHTCX_CRC8_LEN)) {
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temp16 = sys_get_be16(&rx_buf[i]);
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if (shtcx_compute_crc(temp16) != rx_buf[i+2]) {
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LOG_DBG("invalid received invalid crc");
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return -EIO;
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}
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data[dst++] = temp16;
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}
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return 0;
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}
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static int shtcx_sleep(const struct device *dev)
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{
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if (shtcx_write_command(dev, SHTCX_CMD_SLEEP) < 0) {
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return -EIO;
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}
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return 0;
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}
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static int shtcx_wakeup(const struct device *dev)
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{
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if (shtcx_write_command(dev, SHTCX_CMD_WAKEUP)) {
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return -EIO;
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}
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k_sleep(K_USEC(100));
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return 0;
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}
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static int shtcx_sample_fetch(const struct device *dev,
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enum sensor_channel chan)
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{
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struct shtcx_data *data = dev->data;
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const struct shtcx_config *cfg = dev->config;
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__ASSERT_NO_MSG(chan == SENSOR_CHAN_ALL);
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if (cfg->chip == SHTC3) {
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if (shtcx_wakeup(dev)) {
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return -EIO;
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}
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}
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if (shtcx_read_words(dev,
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measure_cmd[cfg->measure_mode][cfg->clock_stretching],
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(uint16_t *)&data->sample, 2,
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measure_wait_us[cfg->chip][cfg->measure_mode]) < 0) {
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LOG_DBG("Failed read measurements!");
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return -EIO;
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}
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if (cfg->chip == SHTC3) {
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if (shtcx_sleep(dev)) {
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LOG_DBG("Failed to initiate sleep");
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return -EIO;
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}
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}
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return 0;
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}
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static int shtcx_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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const struct shtcx_data *data = dev->data;
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if (chan == SENSOR_CHAN_AMBIENT_TEMP) {
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shtcx_temperature_from_raw(data->sample.temp, val);
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} else if (chan == SENSOR_CHAN_HUMIDITY) {
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shtcx_humidity_from_raw(data->sample.temp, val);
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} else {
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return -ENOTSUP;
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}
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return 0;
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}
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static const struct sensor_driver_api shtcx_driver_api = {
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.sample_fetch = shtcx_sample_fetch,
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.channel_get = shtcx_channel_get,
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};
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static int shtcx_init(const struct device *dev)
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{
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const struct shtcx_config *cfg = dev->config;
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uint16_t product_id;
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if (device_is_ready(cfg->bus) == 0) {
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LOG_DBG("i2c bus is not ready");
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return -ENODEV;
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}
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k_sleep(K_USEC(SHTCX_POWER_UP_TIME_US));
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if (cfg->chip == SHTC3) {
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if (shtcx_wakeup(dev)) {
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LOG_ERR("Wakeup failed");
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return -EIO;
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}
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}
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if (shtcx_write_command(dev, SHTCX_CMD_SOFT_RESET) < 0) {
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LOG_ERR("soft reset failed");
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return -EIO;
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}
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k_sleep(K_USEC(SHTCX_SOFT_RESET_TIME_US));
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if (shtcx_read_words(dev, SHTCX_CMD_READ_ID, &product_id, 1, 0) < 0) {
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LOG_ERR("Failed to read product id!");
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return -EIO;
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}
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if (cfg->chip == SHTC1) {
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if ((product_id & SHTC1_ID_MASK) != SHTC1_ID_VALUE) {
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LOG_ERR("Device is not a SHTC1");
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return -EINVAL;
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}
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}
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if (cfg->chip == SHTC3) {
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if ((product_id & SHTC3_ID_MASK) != SHTC3_ID_VALUE) {
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LOG_ERR("Device is not a SHTC3");
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return -EINVAL;
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}
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shtcx_sleep(dev);
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}
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LOG_DBG("Clock-stretching enabled: %d", cfg->clock_stretching);
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LOG_DBG("Measurement mode: %d", cfg->measure_mode);
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LOG_DBG("Init SHTCX");
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return 0;
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}
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#define SHTCX_CONFIG(inst) \
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{ \
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.bus = DEVICE_DT_GET(DT_INST_BUS(inst)), \
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.base_address = DT_INST_REG_ADDR(inst), \
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.chip = DT_ENUM_IDX(DT_DRV_INST(inst), chip), \
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.measure_mode = DT_ENUM_IDX(DT_DRV_INST(inst), measure_mode), \
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.clock_stretching = DT_INST_PROP(inst, clock_stretching) \
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}
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#define SHTCX_DEFINE(inst) \
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static struct shtcx_data shtcx_data_##inst; \
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static struct shtcx_config shtcx_config_##inst = \
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SHTCX_CONFIG(inst); \
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DEVICE_DT_INST_DEFINE(inst, \
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shtcx_init, \
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NULL, \
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&shtcx_data_##inst, \
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&shtcx_config_##inst, \
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POST_KERNEL, \
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CONFIG_SENSOR_INIT_PRIORITY, \
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&shtcx_driver_api);
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DT_INST_FOREACH_STATUS_OKAY(SHTCX_DEFINE)

‎drivers/sensor/shtcx/shtcx.h

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/*
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* Copyright (c) 2021 Thomas Stranger
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#ifndef ZEPHYR_DRIVERS_SENSOR_SHTCX_SHTCX_H_
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#define ZEPHYR_DRIVERS_SENSOR_SHTCX_SHTCX_H_
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#include <device.h>
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#include <devicetree.h>
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#include <kernel.h>
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#include <drivers/gpio.h>
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/* common cmds */
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#define SHTCX_CMD_READ_ID 0xEFC8
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#define SHTCX_CMD_SOFT_RESET 0x805D
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/* shtc3 only: */
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#define SHTCX_CMD_SLEEP 0xB098
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#define SHTCX_CMD_WAKEUP 0x3517
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#define SHTCX_POWER_UP_TIME_US 240U
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/* Soft reset time is 230us for shtc1 and 240us for shtc3 */
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#define SHTCX_SOFT_RESET_TIME_US 240U
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#define SHTCX_MAX_READ_LEN 6
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#define SHTCX_WORD_LEN 2
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#define SHTCX_CRC8_LEN 1
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#define SHTC3_ID_MASK 0x083F
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#define SHTC3_ID_VALUE 0x0807
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#define SHTC1_ID_MASK 0x083F
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#define SHTC1_ID_VALUE 0x0007
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/* defines matching the related enums DT_ENUM_IDX: */
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#define CHIP_SHTC1 0
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#define CHIP_SHTC3 1
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#define MEASURE_MODE_NORMAL 0
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#define MEASURE_MODE_LOW_POWER 1
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enum shtcx_chip {
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SHTC1 = CHIP_SHTC1,
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SHTC3 = CHIP_SHTC3,
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};
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enum shtcx_measure_mode {
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NORMAL = MEASURE_MODE_NORMAL,
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LOW_POWER = MEASURE_MODE_LOW_POWER,
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};
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struct shtcx_sample {
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uint16_t temp;
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uint16_t humidity;
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} __packed __aligned(2);
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struct shtcx_config {
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const struct device *bus;
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uint8_t base_address;
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enum shtcx_chip chip;
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enum shtcx_measure_mode measure_mode;
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bool clock_stretching;
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};
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struct shtcx_data {
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struct shtcx_sample sample;
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};
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static inline uint8_t shtcx_i2c_address(const struct device *dev)
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{
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const struct shtcx_config *dcp = dev->config;
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return dcp->base_address;
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}
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static inline const struct device *shtcx_i2c_bus(const struct device *dev)
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{
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const struct shtcx_config *dcp = dev->config;
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return dcp->bus;
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}
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#endif /* ZEPHYR_DRIVERS_SENSOR_SHTCX_SHTCX_H_ */

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