Tech magnate's hiding place for supporters in garden, maybe (9)

'supporters in garden maybe' is the definition.
I can't tell whether this defines the answer.

'tech magnate's hiding place' is the wordplay.
I cannot quite understand how this works, but
'place' could be 'post' (synonyms) and 'post' is present in the answer.
The remaining letters 'gates' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).

'for' is the link.

Can you help me to learn more?