MacBook Pro USB ports not working properly
Usually (depending on MBP model) - there is only one fully powered / full speed bus. 

You could try resetting the PRAM / NVRAM which also causes a restart to be sure it’s not a temporary situation.

https://support.apple.com/en-us/HT204063

Here is a good support article on USB ports and their corresponding power. 

https://support.apple.com/en-us/HT204377

From my experience iPads can request a lot of power from a standard USB port. Since power management could be involved, the SMC - System Management Controller decides when to apply or deny charging current. You might want to try one time resetting that for your Mac.

https://support.apple.com/en-us/HT201295

If you still have USB issues once that’s done - see about hardware service either in or out of the standard warranty process.