Request for Help on Porting BCM53XX ARM Asus RT-AC88U

[Arınç ÜNAL]

Hello.
I'm working on porting OpenWRT for Asus RT-AC88U router.
----- Quick specs about the router -----
CPU: Broadcom BCM4709C0
Platform: bcm53xx arm
Switch: 4GbE BCM4709C0 + 4GbE Realtek RTL8365MB
Wireless: Broadcom BCM4366C0
128MB NAND
512MB RAM

Realtek Switch and Broadcom Wireless only have proprietary closed
source drivers. Is it legally possible to include these drivers in the
OpenWRT repository?

I'm pretty much new to everything. Thanks to the OpenWRT Wiki, I was
able to quickly take a grasp of how to patch and port to devices.
After putting up a DTS patch, I was able to successfully boot OpenWRT.
Thanks to Sander Vanheule for leading me to the correct direction.

Here is my fork with the commit of DTS: https://github.com/arinc9/openwrt

----- Memory and Partitioning -----
I took shortcuts on specifying partitions and memory without really
understanding what I'm doing.
Let me know if there's anything wrong with memory and partitions.
OpenWRT bootlog https://pastebin.com/7EK0aMVM
AsusWRT bootlog https://pastebin.com/s1sx3cFZ

----- GPIO -----
I was able to specify GPIOs using the GPIO scripts from the OpenWRT Wiki.
Is there a specific naming scheme to GPIO LED and key names?
Where can I find examples like "bcm53xx:white:lan"?
I have put up some "linux,code" entries by looking at device trees of
other bcm53xx devices.
Is there a place I can find the "linux,code" commands for GPIO keys?

----- Help Needed -----
I don't know how to make LAN work. Can anybody experienced with this
architecture give a hand?

Thanks.
Arınç Ü.