Support `embedded-hal 1.0`

[martinmortsell]

embedded-hal has reached 1.0, There are some changes in traits since 0.2 and we should ideally update atsamx7x-hal accordingly.

[michalfita]

We'd need estimate how many changes there are affecting us. I'll try to check this this week.

We probably need a branch for that as target for any related PRs (I wonder if we can divide works into small chunks), so actually we finish release with new PACs first, before new HAL release is addressed.

[BobAdamsEE]

This has been open for a while, and there is a migration guide (looks like a lot to change): https://github.com/rust-embedded/embedded-hal/blob/master/docs/migrating-from-0.2-to-1.0.md

@martinmortsell , are you still working on this? I'm considering poking around at it, but don't want to start doing that if you've made progress on it.

[martinmortsell]

I am not working on it, please go ahead.

[michalfita]

I have on my garden leave to do list taking a look what challenge lies ahead.

[michalfita]

How embedded-hal v1.0.0 looks at first sight:

• It's stripped from some traits, for example for ADC
• There's no ongoing work to bring them back
• Other HAL crates implement a mixture where some of v0.2.7 are still used
• It's significant effort to get this done, which would probably start from disabling implementation for traits non-existing in v1

[tmplt]

Should we feature gate removed traits for the time being?

[michalfita]

@tmplt this would be feature gate, but complex - I looked into embassy code and they as well use mixture of two versions of embedded-hal.

I'm currently spending most of my time looking for new job and attempt to shrink my CV back to two pages. I'll try hack some implementations soon.

[michalfita]

#85 is the draft of attempt to add embedded-hal 1.0 support. The PR targets to epic/feature branch embedded-hal-one-zero where we can target smaller PRs. I think about using new features of sub-issues on GH to target each bit.

If anyone is willing to participate, you're welcome.

TBH not all things in 1.0 I like. In future we should probably add support for Embassy's HAL as well. @jamesmunns suggested to me moving one day under their wings makes sense.

We should look into embedded-hal-nb as well.