I tried to connect my ps3 navigation controller as a last resort since all of my DualShock 3 controllers are broken. Surprisingly, it works perfectly. : r/PSP
PSP Store Closes Next Week, But Sony Will Still Sell PSP Games Through PS3 And PS Vita - Game Informer
PSP Maplus: Portable Navi 3 4560286835063 From Japan | eBay