driver/lsm6dsxx: Allow generic LSM6DSXX driver

[MrKevinWeiss]

Contribution description

We noticed that the different variants of the feather-nrf52840-sense boards (B/C) have different LSM6DSXX variants. Instead of making 2 different boards, we would just allow the LSM6DSXX module to be used by itself and only the generic (so far all of them) functions can be used.

This also allows automated tests to be run... with some fun surprises along the way.

Testing procedure

Run the following on both variants:

BUILD_IN_DOCKER=1 make -C tests/drivers/lsm6dsxx flash test-with-config

both should pass...

Issues/PRs references

[MrKevinWeiss]

ping @MichelRottleuthner @mguetschow

[mguetschow]

Thanks for looking into this! 👍 Two questions below.

Can confirm this (still) works here with board revision B.

[MrKevinWeiss]

Although, after looking a bit through the datasheet it would appear that this may not work.

The LSM6DS33 has this temp sensor

and the LSM6DSL has this:

[MrKevinWeiss]

I guess this means we have to runtime check the whoami register and use those values for calculating the temp (and anything else that shows up).

[MrKevinWeiss]

Also temperature offset of +-15 I don't understand

[MichelRottleuthner]

Just to make sure there is no confusion: the driver currently supports two variants (LSM6DS33 and LSM6DSL). The new feather board rev. C uses neither of them. It uses the LSM6DS3TR-C. Although LSM6DSL and LSM6DS3TR-C seem very similar its probably still better to check against all datasheets ;)

Also temperature offset of +-15 I don't understand

I interpret it as "the temperature sensor will have pretty poor accuracy in terms of absolute temperature" i.e., a register value of 0 refers to something between 10 °C and 40 °C

[mguetschow]

Is there no way of telling doxygen that a define is only used internally? Something like @internal?

[MrKevinWeiss]

probably but I don't know how... this is what we did for the others.

[mguetschow]

Would it make sense to just skip internal header files for the generated documentation? ala https://stackoverflow.com/questions/11025971/separate-internal-from-external-documentation-in-doxygen with @cond

or just skip those for the "missing documentation" check?

[MrKevinWeiss]

May I squash (seeing as the first commit won't work for our use case)?

[riot-ci]

Murdock results

✔️ PASSED

b98e5bd dist/tools/doccheck/exclude_simple: Add LSM6 excludes

Success	Failures	Total	Runtime
10031	0	10031	09m:45s

Artifacts

[MrKevinWeiss]

squashy squashy

[mguetschow]

squashy squashy

Go for it!

[mguetschow]

Two more minor things (you may squash directly).

[MrKevinWeiss]

ping @mguetschow all good?

[mguetschow]

Yes, LGTM, thanks! Also tested locally to (still) work on the rev. B board.

[MrKevinWeiss]

Thanks! Next will be adding it to saul I guess :)