I'm planning to start a new project with a Raspberry Pi 3 B+ or A+ and the official Raspberry Pi Touchscreen. I've never used this screen so I have a question about it and can't find any answer here or on Internet.
For this project, I will design a daughter board that supplies power at different voltages (12, 5 and 3.3VDC). The power will be supplied to the Pi through the GPIOs (pins #2 and #6 if I'm right) from the 5VDC of this external daughter board. I'm already using this kind of setup on a UDOONeo and it's working fine.
But, now, I need to know if it's ok for the Pi to have its power supplied from the GPIOs and then have the Pi Touchscreen draining power from the GPIO too. I won't use USB at all to supply power to the Pi or the touchscreen.
Is it possible to do this ?
Thanks to all who will take a little of their time to answer me. If something is not clear (bad explanations or English), please let me know.