A new device tree from scratch

Please pardon me for my absurd question. I have an ARM android device
for which I want to develop device tree. I have the kernel source for
the device but the kernel is very old (3.4.67)doesn't have any device
tree source files. But it has board specific files at mach-mediatek.
Is there any way to use those board files and build or generate a
device tree using any software or manually? Please give me hints, I
want to know.

Alif