A quick search in Linux git head for "th1520" returned some results. It must mean there is ongoing work. I hope they set up a webpage to track what's going on

A quick search in Linux git head for "th1520" returned some results. It must mean there is ongoing work. I hope they set up a webpage to track what's going on with upstreaming efforts, similar to JH7110 has. Notably, boards with TH1520 are just starting to ship, whereas boards with JH7110 were shipping in volume in February.