ST LSM6xxx IMU sensors do not report I2C errors via function return value

[mmatthe]

So, I just played around with an LSM6DSO sensor, using this driver: https://github.com/zephyrproject-rtos/zephyr/tree/5c7f47de0fdeac237c420bc06070bf8d9d0dec03/drivers/sensor/st/lsm6dso

The driver works well and can read the IMU values easily.

Naturally, upon disrupting the I2C connection (e.g. by removing the SDA cable on the breadboard), the readings of the sensor are wrong. Also, in the UART console, I get messages like those:

[00:16:58.689,056] <dbg> LSM6DSO: lsm6dso_sample_fetch_gyro: Failed to read sample                               
[00:16:58.698,425] <dbg> LSM6DSO: lsm6dso_sample_fetch_accel: Failed to read sample

However, the function lsm6dso_sample_fetch does not return an error code in this case. The reason is that the return values of the underlying functions is ignored, (e.g. here).

Is this worth a bug report to Zephyr or should I try to approach ST to fix this?

[ldomaigne]

If it is a small change, it could be a nice little PR.