You likely need somebody (yourself???) with the device to do the porting, as it requires converting the hardware description to be DTS based and then compiling and testing the firmware images.
Rather long thread about ath79 advice is here:
You might read/browse the thread to see the typical steps in the conversion.
And then look at the examples of adding new devices.
e.g.
https://git.openwrt.org/?p=openwrt/openwrt.git;a=commitdiff;h=30dcbc741d84e36ea5408d99593ccb35f900cb5e
or
https://git.openwrt.org/?p=openwrt/openwrt.git;a=commitdiff;h=6d6985ff0e41c89650d72d2b5c0c938c2f39906e