Rewrite prescaler enum in ATtiny xmega SPI*.CTRLA

[innermatrix]

This uses the same convention as SPI FOSC* in patch/common/spi.yaml

[Rahix]

Thanks! Do you have more changes of this kind planned or do you consider the ATtiny XMEGA support ready for release now? Just want to make sure I don't release a new version of avr-device just to then pull more breaking changes for one of the new MCUs :)

[innermatrix]

Thanks! Do you have more changes of this kind planned or do you consider the ATtiny XMEGA support ready for release now? Just want to make sure I don't release a new version of avr-device just to then pull more breaking changes for one of the new MCUs :)

On the one hand I don't have any further changes (breaking or non-breaking) sitting in my WIP PRs.

On the other hand, avr-hal-generic has limited support for xmega peripherals, so I am incrementally building that out in my fork of avr-hal and it's not out of the question that as I build that out I might discover more changes are needed in avi-device. Thus far I got I2C host, SPI host, and USART support in avr-hal-generic to compile against these changes in avr-device, so I am moderately confident about those, but I haven't touched PWM, ADC, or EEPROM yet, so those I am less confident about.

Tell me your thoughts? If you'd prefer to keep these devices out until I feel more confident, I am fine with that.

[Rahix]

If changes become necessary, we'll do them as they arise. Just wanted to know if you are sitting on any more known pending issues. But if not, then I'll be optimistic and cut a new release soon :)

[innermatrix]

Nope, you're fully caught up on my WIP now 🙂 Thanks!