deidara called him tobi..ofcourse he did. I think everytime certain characters called him tobi while he was using his madara persona they were actually saying obito. But kishi decided to write tobi so that us fans won't know. if you think about it while obito was playing madara. only those that called him tobi new his true identity. kabuto, zetsu and kisame
It's a shame he was so easily controlled by a name he didn't care about.It was always implied that Kabuto knew Tobi's true identity when he revealed the coffin with edo Madara in it. I believe Kabuto even said something like "don't worry I haven't told anyone, your true identity." That's how he blackmailed Tobi to let him kinda be a honorary member of Akatsuki