GPIO giving No access to /dev/mem. Try running as root!

Hi

Followed this site http://wiki.lemaker.org/BananaPro/Pi:GPIO_library#Installation

but unable to blink a single LED on my banana pi m4

It gives the following error

No access to /dev/mem. Try running as root! Tried with sudo and sudo su -i too.

And there is no official documentation as well

Can anybody tell us how to do

Thanks in advance

Very disappointed to see there is absolutely no support for GPIO!!

There is no support for anything.

List of problems 1-SD card doesn’t get detected after booting from emmc 2-Above GPIO issue 3-Internal WIFI chip is literally a joke, have to keep a hotspot device next to it to get connectivity. 4-have 64GB sd card but only 8GB get recognized and we are left with around 800MB of storage.