PX4 Drivers X NuttX Drivers

Hello. I have talked to a colleague who knows a lot about Nuttx and he told me that the PX4 drivers do not follow exactly what is prescribed by Nuttx, at least for the previous PX4 versions (he was not sure about the new versions). One point that he brought was direct access to peripherals.

I kind of checked the driver for PX4 and compared it with drivers definitions for NuttX and I did not find where could be any noncompliance with NuttX drivers abstraction model.
Could anyone add something about it?

Thanks in advance.