Overlays in U-boot for beaglebone

[GauravChoube]

Hi,
I have build uboot and kernel from https://www.digikey.com/eewiki/display/linuxonarm/BeagleBone+Black
and create SD card as per instrucution.This one having minimal image.
i want to add overlays in order to do change status of some pin(High to low).
I dont want to build kernel again.
When searched the inertnet all are old one slote base overlay.
but in my image there in bb_cap_manager in /etc/device/ and not slot file.
After read some thread,got to know and overlays is shifted uboot and there is not kernel overlays.
Can anyone explain me how to create overlays first all and how to add in uboot.
Any help will be appreciated.

[tehkillerbee]

A really good starting point is https://elinux.org/Beagleboard:BeagleBoneBlack_Debian#U-Boot_Overlays
Take a look at "U-Boot Override external capes"

Creating your own overlays requires writing your own .dts files and compiling them to .dtbo. I suggest using the existing sources as a starting point and then modifying them according to your needs. Find examples here:
https://github.com/beagleboard/bb.org-overlays/tree/master/src/arm

1. Clone this git repository (https://github.com/beagleboard/bb.org-overlays) and install it (look at the readme.md for instructions). This includes the toolchain for compiling the dts to dtbo. I cloned it on my beaglebone as it was easier so I have not tested using my PC to compile the files.

2. Create your own dts source file/modify existing sources and save it in your local clone of the repository (eg. save it in ~/bb.org-overlays/src/arm/BB-XYZ-00A0.dts)

3. Compile it:
   cd ~/bb.org-overlays
   make
   sudo cp src/arm/BB-XYZ-00A0.dtbo /lib/firmware/BB-XYZ-00A0.dtbo

[jadonk]

@GauravChoube can this issue be closed?