Wed May 16 09:11:56 EDT 2018
beaglebone, pru, devicetree
Confusing stuff. Some notes.
Device tree is just a data structure. The structure usually reflects
some hierarchy of the chip or driver, but otherwise seems rather
arbitrary. The structure is queried from the driver.
It appears the driver's probe routine already has the node reference,
so this is likely gathered from the 'compatible' part.
GPIOs are not pins. Pins seem to always be behind a multiplexer which
is abstracted in Linux behind a 'pinctrl' interface. GPIOs are a
separate entity inside the chip, which can be muxed to pins, or not.