Make SpiDevice generic over Word size and implement u16 transfer

[Ragarnoy]

It's not particularly complicated, this allows to be more in line with other implementations like ExclusiveDevice which also has an u16 word size

[Dirbaio]

I think it should be possible to avoid adding the generic param to the struct itself, using it on impls only. This way you don't have to choose a word size when creating the SpiDevice, it'll just transparently implement all transfer sizes the underlying bus implements.

[Dirbaio]

Also, SpiDevice should not implement the embedded-hal v0.2 SPI traits. Those are equivalent to the 1.0 SpiBus, ie they're for a bare bus without any CS pin.

[Ragarnoy]

Also, SpiDevice should not implement the embedded-hal v0.2 SPI traits. Those are equivalent to the 1.0 SpiBus, ie they're for a bare bus without any CS pin.

Yeah, I was quite confused about that but went along with it. The traits that were used (Transfer, Write) do not exist anymore, so I removed them, is this correct ?

[Dirbaio]

oh, they were already there. my bad, I misread the diff and thought you had added them. hmmm :|

[mattico]

Thanks @Ragarnoy, I was going to implement this today!