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Alexander Wachter
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drivers: sensor: ens210: Implement AMS ens210 Sensor
Implementation of AMS (Austria Micro Systems) ENS210 temperature and relative humidity sensor. Signed-off-by: Alexander Wachter <[email protected]>
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‎drivers/sensor/CMakeLists.txt‎

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@@ -15,6 +15,7 @@ add_subdirectory_ifdef(CONFIG_BMI160 bmi160)
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add_subdirectory_ifdef(CONFIG_BMM150 bmm150)
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add_subdirectory_ifdef(CONFIG_CCS811 ccs811)
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add_subdirectory_ifdef(CONFIG_DHT dht)
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add_subdirectory_ifdef(CONFIG_ENS210 ens210)
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add_subdirectory_ifdef(CONFIG_FXAS21002 fxas21002)
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add_subdirectory_ifdef(CONFIG_FXOS8700 fxos8700)
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add_subdirectory(grove)

‎drivers/sensor/Kconfig‎

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@@ -55,6 +55,8 @@ source "drivers/sensor/ccs811/Kconfig"
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source "drivers/sensor/dht/Kconfig"
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source "drivers/sensor/ens210/Kconfig"
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source "drivers/sensor/fxas21002/Kconfig"
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source "drivers/sensor/fxos8700/Kconfig"

‎drivers/sensor/ens210/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_ENS210 ens210.c)

‎drivers/sensor/ens210/Kconfig‎

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# Kconfig - ENS210 Digital Temperature and Humidity sensor configuration options
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#
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# Copyright (c) 2018 Alexander Wachter.
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#
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# SPDX-License-Identifier: Apache-2.0
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#
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menuconfig ENS210
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bool "ENS210 Digital Temperature and Humidity sensor"
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depends on I2C && HAS_DTS_I2C
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help
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Enable driver for ENS210 Digital Temperature and Humidity sensor.
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if ENS210
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config ENS210_CRC_CHECK
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bool "Enable CRC Check"
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default y
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help
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Check the crc value after data reading.
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config ENS210_MAX_STAT_RETRIES
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int "Number of status read retries"
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default 4
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help
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Number of retries when status reading failed or device not ready.
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config ENS210_MAX_READ_RETRIES
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int "Number of value reading retries"
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default 4
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help
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Number of retries when value reading failed, value not valid
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or crc not ok.
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endif # ENS210

‎drivers/sensor/ens210/ens210.c‎

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/*
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* Copyright (c) 2018 Alexander Wachter.
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#include <device.h>
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#include <i2c.h>
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#include <kernel.h>
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#include <misc/byteorder.h>
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#include <misc/util.h>
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#include <sensor.h>
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#include <misc/__assert.h>
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#include <logging/log.h>
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#include "ens210.h"
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#define LOG_LEVEL CONFIG_SENSOR_LOG_LEVEL
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LOG_MODULE_REGISTER(ENS210);
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#ifdef ENS210_CRC_CHECK
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u32_t ens210_crc7(u32_t bitstream)
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{
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u32_t polynomial = (ENS210_CRC7_POLY << (ENS210_CRC7_DATA_WIDTH - 1));
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u32_t bit = ENS210_CRC7_DATA_MSB << ENS210_CRC7_WIDTH;
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u32_t val = (bitstream << ENS210_CRC7_WIDTH) | ENS210_CRC7_IVEC;
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while (bit & (ENS210_CRC7_DATA_MASK << ENS210_CRC7_WIDTH)) {
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if (bit & val) {
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val ^= polynomial;
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}
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bit >>= 1;
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polynomial >>= 1;
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}
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return val;
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}
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#endif /*ENS210_CRC_CHECK*/
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static int ens210_sample_fetch(struct device *dev, enum sensor_channel chan)
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{
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struct ens210_data *drv_data = dev->driver_data;
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struct ens210_value_data data[2];
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int ret, cnt;
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#ifdef ENS210_CRC_CHECK
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u32_t temp_valid, humidity_valid;
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#endif /*ENS210_CRC_CHECK*/
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__ASSERT_NO_MSG(chan == SENSOR_CHAN_ALL);
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for (cnt = 0; cnt <= CONFIG_ENS210_MAX_READ_RETRIES; cnt++) {
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ret = i2c_burst_read(drv_data->i2c, DT_AMS_ENS210_0_BASE_ADDRESS,
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ENS210_REG_T_VAL, (u8_t *)&data, sizeof(data));
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if (ret < 0) {
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LOG_ERR("Failed to read data");
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continue;
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}
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if (!data[0].valid) {
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LOG_WRN("Temperature not valid");
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continue;
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}
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if (!data[1].valid) {
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LOG_WRN("Humidity not valid");
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continue;
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}
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#ifdef ENS210_CRC_CHECK
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temp_valid = data[0].val |
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(data[0].valid << (sizeof(data[0].val) * 8));
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humidity_valid = data[1].val |
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(data[1].valid << (sizeof(data[1].val) * 8));
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if (ens210_crc7(temp_valid) != data[0].crc7) {
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LOG_WRN("Temperature CRC error");
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continue;
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}
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if (ens210_crc7(humidity_valid) != data[1].crc7) {
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LOG_WRN("Humidity CRC error");
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continue;
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}
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#endif /*ENS210_CRC_CHECK*/
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drv_data->temp = data[0];
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drv_data->humidity = data[1];
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return 0;
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}
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return -EIO;
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}
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static int ens210_channel_get(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 ens210_data *drv_data = dev->driver_data;
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s32_t temp_frac;
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s32_t humidity_frac;
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switch (chan) {
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case SENSOR_CHAN_AMBIENT_TEMP:
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/* Temperature is in 1/64 Kelvin. Subtract 273.15 for Celsius */
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temp_frac = sys_le16_to_cpu(drv_data->temp.val) * (1000000 / 64);
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temp_frac -= 273150000;
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val->val1 = temp_frac / 1000000;
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val->val2 = temp_frac - val->val1;
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break;
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case SENSOR_CHAN_HUMIDITY:
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humidity_frac = sys_le16_to_cpu(drv_data->humidity.val) *
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(1000000 / 512);
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val->val1 = humidity_frac / 1000000;
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val->val2 = humidity_frac - val->val1;
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break;
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default:
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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 int ens210_sys_reset(struct device *i2c_dev)
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{
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const struct ens210_sys_ctrl sys_ctrl = {.low_power = 0, .reset = 1};
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int ret;
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ret = i2c_reg_write_byte(i2c_dev, DT_AMS_ENS210_0_BASE_ADDRESS,
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ENS210_REG_SYS_CTRL, *(u8_t *)&sys_ctrl);
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if (ret < 0) {
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LOG_ERR("Failed to set SYS_CTRL to 0x%x", *(u8_t *)&sys_ctrl);
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}
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return ret;
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}
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static int ens210_sys_enable(struct device *i2c_dev)
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{
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const struct ens210_sys_ctrl sys_ctrl = {.low_power = 0, .reset = 0};
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int ret;
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ret = i2c_reg_write_byte(i2c_dev, DT_AMS_ENS210_0_BASE_ADDRESS,
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ENS210_REG_SYS_CTRL, *(u8_t *)&sys_ctrl);
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if (ret < 0) {
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LOG_ERR("Failed to set SYS_CTRL to 0x%x", *(u8_t *)&sys_ctrl);
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}
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return ret;
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}
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static int ens210_wait_boot(struct device *i2c_dev)
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{
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int cnt;
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int ret;
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struct ens210_sys_stat sys_stat;
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for (cnt = 0; cnt <= CONFIG_ENS210_MAX_STAT_RETRIES; cnt++) {
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ret = i2c_reg_read_byte(i2c_dev, DT_AMS_ENS210_0_BASE_ADDRESS,
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ENS210_REG_SYS_STAT,
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(u8_t *)&sys_stat);
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if (ret < 0) {
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k_sleep(1);
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continue;
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}
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if (sys_stat.sys_active) {
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return 0;
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}
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if (cnt == 0) {
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ens210_sys_reset(i2c_dev);
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}
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ens210_sys_enable(i2c_dev);
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k_sleep(2);
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}
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if (ret < 0) {
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LOG_ERR("Failed to read SYS_STATE");
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}
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LOG_ERR("Sensor is not in active state");
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return -EIO;
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}
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static const struct sensor_driver_api en210_driver_api = {
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.sample_fetch = ens210_sample_fetch,
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.channel_get = ens210_channel_get,
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};
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static int ens210_init(struct device *dev)
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{
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struct ens210_data *drv_data = dev->driver_data;
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const struct ens210_sens_run sense_run = {
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.t_run = 1,
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.h_run = 1
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};
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const struct ens210_sens_start sense_start = {
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.t_start = 1,
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.h_start = 1
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};
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int ret;
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u16_t part_id;
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drv_data->i2c = device_get_binding(DT_AMS_ENS210_0_BUS_NAME);
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if (drv_data->i2c == NULL) {
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LOG_ERR("Failed to get pointer to %s device!",
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DT_AMS_ENS210_0_BUS_NAME);
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return -EINVAL;
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}
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/* Wait until the device is ready. */
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ret = ens210_wait_boot(drv_data->i2c);
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if (ret < 0) {
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return -EIO;
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}
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/* Check Hardware ID. This is only possible after device is ready */
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ret = i2c_burst_read(drv_data->i2c, DT_AMS_ENS210_0_BASE_ADDRESS,
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ENS210_REG_PART_ID, (u8_t *)&part_id,
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sizeof(part_id));
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if (ret < 0) {
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LOG_ERR("Failed to read Part ID register");
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return -EIO;
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}
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if (part_id != ENS210_PART_ID) {
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LOG_ERR("Part ID does not match. Want 0x%x, got 0x%x",
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ENS210_PART_ID, part_id);
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return -EIO;
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}
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/* Set continuous measurement */
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ret = i2c_reg_write_byte(drv_data->i2c, DT_AMS_ENS210_0_BASE_ADDRESS,
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ENS210_REG_SENS_RUN, *(u8_t *)&sense_run);
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if (ret < 0) {
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LOG_ERR("Failed to set SENS_RUN to 0x%x",
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*(u8_t *)&sense_run);
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return -EIO;
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}
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/* Start measuring */
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ret = i2c_reg_write_byte(drv_data->i2c, DT_AMS_ENS210_0_BASE_ADDRESS,
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ENS210_REG_SENS_START, *(u8_t *)&sense_start);
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if (ret < 0) {
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LOG_ERR("Failed to set SENS_START to 0x%x",
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*(u8_t *)&sense_start);
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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 struct ens210_data ens210_driver;
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DEVICE_AND_API_INIT(ens210, DT_AMS_ENS210_0_LABEL, ens210_init, &ens210_driver,
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NULL, POST_KERNEL, CONFIG_SENSOR_INIT_PRIORITY,
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&en210_driver_api);

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