How to add SPI device to HLK-7688

Hello everyone!
I'm using HLK-7688 module wifi from Hi-Link. But, the firmware for HLK-7688 is closed. So I have built the HLK's firmware follow Linkit Smart 7688. The HLK-7688 has two CS pins and one MISO, one MOSI, one SCK (SPI's clock). CS0 for communicating SPI flash inside the HLK-7688 and CS1 is free. I want you cs1 for my application which communicating with RAK831 through SPI flash. I just edited the device tree file on /target/linux/ramips/dts. I want use CS1 and SPI's clock when work with RAK831 module is 8Mhz. So anyone helps me that look my custom device tree file and advice me the better solution or which file I should edit.
Thank in advance!
P/s: my link to files device tree for building kernel. ( I use openwrt 15.05.1 source code.

This seems to be a follow-on/duplicate of

You can edit the title of that thread to reflect your current understanding of the help you need. Perhaps something like "How to Add SPI Device to (ramips) HLK-7688 / Linkit-7688"

Clicking the "pencil" icon lets you edit the title and category


I've moved that thread to the For Developers section already.