Handle register with mode as child

[flobz]

Improve handling of atmega4809.atfd
Required for Rahix/avr-hal#97

[Rahix]

Please check the CI failures.

[flobz]

Please check the CI failures.

It should be fix.

[Rahix]

Thanks a lot for the contribution! I have a few minor review comments, see below.

From my understanding, this shouldn't change any existing register/field descriptions, it should just be adding new fields from the modes in the ATDF, right?

Also, just need to say this: I really really appreciate that you split this PR into two commits such that the changes to the generated SVD snapshot are visible in the diff of the second commit. This makes understanding the effects so much easier and not many people are willing to put this much effort in. Thanks :)

[flobz]

Thanks for all your feedbacks, I appreciate !

From my understanding, this shouldn't change any existing register/field descriptions, it should just be adding new fields from the modes in the ATDF, right?

Yes, that's right. For example, it will add the NORMAL_CHSIZE bitfield, which is required for USART on Arduino nano every as you can see here.

[Rahix]

Thanks :)

[flobz]

Thanks for merging, do you plan to do a new release of atdf2svd and avr-device soon ?

[Rahix]

Just took care of the atdf2svd release, will do avr-device in the coming days.

[flobz]

@Rahix would you able to do an avr-device release soon ? 😄

[Rahix]

Just a heads up, your changes have hit avr-device main branch so they are pending for the next release which is hopefully not far off :)

[Rahix]

And here's the release: https://github.com/Rahix/avr-device/releases/tag/v0.7.0