During the final year of my PhD, my relationship with my advisor experienced a significant non-trivial breakdown. However, for the years prior, we had a good relationship. The deterioration of this relationship wasn't due to anything extreme, and it wasn't a situation where all lines were crossed, but it was a serious clash of personalities up to the point that I did not ask a recommendation from him, and I told him I would make it on my own. I published my thesis work as single-author papers and secured funding to support my postdoc; I do not need letters or support from him, and he is aware of this. Now, I want to know if there is any way to repair this relationship. Partly, this is because we are still at the same institution, and it's awkward, but mostly because I genuinely want to mend things.
My question is mainly directed towards PIs who have had several students: do you think it is possible to fix this? Certainly, there will be some awkwardness to overcome, but would you find any incentive to do so? how should I approach him? I don't want to reach out only to be ignored or face a similar response, note that we are still at the same institution, which can make things even more awkward, at least for me.