Sai Baba origins are still a mystery but he's considered as a Sufi just like Karnataka’s Shishunaala Shareeff/Shishunaal Shariff ( a Muslim scholar influenced by Hinduism and it's teachings).
His Real name was said to be Chandmia Sye Uddin based on reports.
Unlike Shishunaal Shariff Sai Baba wasn't a poet or philosopher.