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Expose a Sensor API

Updated: 7/10/26

Use Zephyr's Sensor API when the device fits standard sensor channels (accel, gyro, temp, etc.). The MPU6050 driver is the reference. See also the Zephyr Sensor API.

For devices that need a custom function table instead, see Expose a Custom API.

1. Include the Sensor API

In src/<chip>.h, include the sensor header and drop the template's custom struct <chip>_driver_api — Sensor API drivers use struct sensor_driver_api from Zephyr:

#include <zephyr/drivers/sensor.h>

Keep struct <chip>_config and struct <chip>_data. Cache raw samples in _data for library-backed backends (wrap those fields in #if !defined(CONFIG_PEROVSAT_<CHIP>_BACKEND_PUBLIC_MOCK) if they are unused by public mock).

2. Implement sample_fetch and channel_get

In src/<chip>.c, implement both functions with a public-mock branch:

#if !defined(CONFIG_PEROVSAT_<CHIP>_BACKEND_PUBLIC_MOCK)

static int sample_fetch(const struct device *dev, enum sensor_channel channel)
{
    struct <chip>_data *data = dev->data;

    ARG_UNUSED(channel);
    return <chip>_lib_sample_fetch(<chip>_transfer, (void *)dev, /* outputs… */);
}

static int channel_get(const struct device *dev, enum sensor_channel channel,
               struct sensor_value *val)
{
    struct <chip>_data *data = dev->data;
    /* Convert cached raw values into struct sensor_value for the channel */
    …
}

#else /* public-mock */

static int sample_fetch(const struct device *dev, enum sensor_channel channel)
{
    ARG_UNUSED(dev);
    /* Accept the channels you support; return -ENOTSUP otherwise */
    return 0;
}

static int channel_get(const struct device *dev, enum sensor_channel channel,
               struct sensor_value *val)
{
    ARG_UNUSED(dev);
    /* Return hardcoded sensor_value data for supported channels */
    …
}

#endif

sample_fetch pulls raw data into driver-private storage (or no-ops for public mock). channel_get converts cached raw values into struct sensor_value.

3. Register with SENSOR_DEVICE_DT_INST_DEFINE

The template defaults to DEVICE_DT_INST_DEFINE. Switch to the sensor macro and point at sensor_driver_api:

const struct sensor_driver_api <chip>_api = {
    .sample_fetch = sample_fetch,
    .channel_get = channel_get,
};

#define <CHIP>_INIT(inst)                                                                          \
    static struct <chip>_data <chip>_data_##inst;                                              \
    static const struct <chip>_config <chip>_config_##inst = {                                 \
        /* DT_INST_PROP / bus fields */                                                    \
    };                                                                                         \
    SENSOR_DEVICE_DT_INST_DEFINE(inst, <chip>_init, NULL, &<chip>_data_##inst,                 \
                     &<chip>_config_##inst, BOOT_STAGE, BOOT_PRIORITY,            \
                     &<chip>_api);

DT_INST_FOREACH_STATUS_OKAY(<CHIP>_INIT)

4. Application usage

const struct device *imu = DEVICE_DT_GET(DT_ALIAS(imu));

sensor_sample_fetch(imu);
sensor_channel_get(imu, SENSOR_CHAN_ACCEL_XYZ, accel);
sensor_channel_get(imu, SENSOR_CHAN_GYRO_XYZ, gyro);