I know the Banana team are working hard right now to provide the best possible support in the kernel - I'm currently testing and developing on my R2 (had it a week now - it's fantastic!) so if I'm making any patches to my kernel and I've got the time - I'll back port the latest 7530 patches and drop you a message on here
Support is great so far and judging from the amount of work being done? I should expect we'll see support for the SoC and the 7530 in mainline soon enough!
Until then we have everything we need - just need to get our feet wet - isn't that half the fun?