When building the kernel, make sure the following is enabled in the menuconfig:
Networking Support ---> Wireless ---> nl80211 testmode command
If not, the WiFi may not scan.
From there, you'll need to copy the NVS file from the 3.0.x kernel BSP.
The stock BSP has 3 NVS files. That driver have been modified to identify the chip type and load the corresponding driver. Since the mainline kernel does not have this feature, you'll have to manually copy the nvs file.
By default the system builds an generic NVS file for a WL127x driver which won't work with the WL128x.
If you skip this step, the driver will fail when it attempts to load the NVS file because the file sizes don't match.
The NVS file from the 3.0x BSP should be located in /lib/firmware/ti-connectivity
Copy it to /lib/firmware/ti-connectivity/wl127x-nvs.bin on the rootfs of the SOM. This may be counter intuitive because there is a 128x-nvs.bin file already, but the driver does not load that file for some reason.
If you do not copy the correct NVS file, the Torpedo + Wireless will not be in compliance with FCC or IC rules.