He donates to his own foundation to get tax breaks
Actually, you are wrong here. There isn't any evidence that he has donated to his foundation for many years. After all, if you don't pay any tax, there is no tax break to be had from donations!
Sort of. What I read with this, is that for several corporate personal appearances, he directed that his appearance fee be donated to his foundation. He did this with (I think) Comedy Central for a $400,000 fee. By the tax code, a directed donation under these circumstances is a donation by *him*, not by Comedy Central. The problem for Trump there, is that for a case like that, while he doesn't owe income tax for that directed donation (assuming the Trump Foundation keeps its tax-exempt status, which is looking less likely), he does owe payroll tax for it, which is about 12%.
So there is tax to be paid, but not income tax. This is part of how Hillary Clinton can (somewhat correctly, speculatively) accuse Trump of not paying any federal income tax for years, and Trump can (honestly) reply that he has paid lots of taxes over the years. She says "federal income tax" and he says "tax", and they aren't talking about the same thing. That's on purpose by both of them.