Check simplified generic_sdr PHY / Apply changes to generic_ddr PHY.

[enjoy-digital]

Hi @pawelsag, @piotr-binkowski,

I did some simplifications to to the generic_sdr PHY and tested it on the iCEBreaker/Arty boards while doing these changes. Could you check that it's still also working correctly on your boards?

I tried to commit each simplification step, could you try to also apply similar silmplifications to the generic_ddr PHY?

Thanks,

Florent

[enjoy-digital]

@piotr-binkowski: I stared some simplifications on top of #59:

• 7b30116
• ff72f95
• 90228ab
• 5b8ca95

I was testing on the Arty while doing the changes, can you verify it's also working fine on your side (CrossLink-NX)?

[enjoy-digital]

I just did other simplifications on top of this:

• enjoy-digital/litex@0877920
• 229edea
• 6991bef
• 8b4d0c3

Theses changes should not changed the behavior but it would be nice to have feedback on the Crosslink NX. I also think we can simplify LiteSPIDDRPHYCore by changing the clk polarity as done in #60 and validated on Arty (for reads). Can you check @piotr-binkowski, @kgugala and merge if working on your config?