Custom Resolution for Nanopi M3

I have a single board computer (nanopi m3), which only supports a resolution of 1280 x 720 and 1920 x 1080 if change need to recompile the kernel in

https://github.com/friendlyarm/linux...nanopi3/lcds.c

but I have two monitors with a native resolution of 1600 x 900 and 1366 x 768,
how to edit or sample code to change the resolution using hdmi 1600 x 900 and 1366 x 768 ??(I use a hdmi to vga convert)