Hi,
As described in my previous question https://www.toradex.com/community/questions/58635/lvds-display-integration-with-imx8mm-verdin-and-da.html?childToView=58948#comment-58948 I was able to create Yocto Linux image, modify device tree using mmc mode (ums 0 mmc 0, copy paste dtbo file into overlays folder, and edit overlays.txt file from my host machine) and got custom display working fine.
Now I have tried to do same from Yocto build to include my version of DTBO file into device instead of default verdin-imx8mm_lt8912_overlay.dtbo.
I have functional layer for kernel
├── linux-toradex
│ └── defconfig
├── linux-toradex_%.bbappend
…and I have my-overlay.dts file and I know it is ok cause tried it.
I have also own machine version verdin-imx8mm-h.conf and changes local.conf:
├── apalis-imx8.conf
├── colibri-imx8x-v10b.conf
├── include
│ ├── apalis-imx6.inc
│ ├── colibri-imx7.inc
│ └── README
├── verdin-imx8mm.conf
├── **verdin-imx8mm-my.conf**
└── verdin-imx8mp.conf
verdin-imx8mm-my.conf I have this:
TEZI_EXTERNAL_KERNEL_DEVICETREE_BOOT = “my-overlay.dtbo”
I know Yocto build will fetch all the overlay files using this recipe: device-tree-overlays_git.bb from git://git.toradex.com/device-tree-overlays.git
I want my my-overlay.dts file to be integrated together of Toradex default files which allow me to change configuration using mmc mode and uboot.
I have created device-tree-overlays_git.bbappend recipe into my layer, used many different approach but not succeeded.
├── conf
│ └── layer.conf
├── recipes-images
└── recipes-kernel
└── linux
├── device-tree-overlays_git
│ └── my-overlay.dts
├── device-tree-overlays_git.bbappend
├── linux-toradex
│ └── defconfig
└── linux-toradex_%.bbappend
Typically the error is my-overlay.dts is not found from the search path. I have tried to define FILESEXTRAPATHS_append, FILESEXTRAPATHS_prepend and SRC_URI using different locations and definitions but not succeeded with Yocto build. I have also tried to but my my-overlay.dts into several different folders but bitbake will never find it. Base recipe fetch something from GIT and appended recipe should fetch something more from local folder.–mission impossible ? 
This is my current version of device-tree-overlays_git.bbappend
SUMMARY = "Toradex BSP device tree overlays for my great machine"
DESCRIPTION = "Toradex BSP device tree overlays from within layer."
CUSTOM_DEVICETREE = "my-overlay.dts"
# I have tried everything here X-)
FILESEXTRAPATHS_append := ":${THISDIR}"
#FILESEXTRAPATHS_prepend := "${THISDIR}/{$PN}:"
SRC_URI += "file://${CUSTOM_DEVICETREE}"
First I get this warning:
WARNING: device-tree-overlays-toradex_5.4-2.1.x-imx+gitAUTOINC+106305bdf4-r0 do_fetch: Failed to fetch URL file://my-overlay.dts, attempting MIRRORS if available
and then errors like:
ERROR: device-tree-overlays-toradex_5.4-2.1.x-imx+gitAUTOINC+106305bdf4-r0 do_fetch: Fetcher failure: Unable to find file file://my-overlay.dts anywhere. The paths that were searched were:
/home/vesaeskola/nnnn_work/nnnn-psw-manifest/tdx/build/…/layers/meta-nnnn/recipes-kernel/linux/tdx
/home/vesaeskola/nnnn_work/nnnn-psw-manifest/tdx/build/…/layers/meta-toradex-nxp/recipes-kernel/linux/device-tree-overlays-toradex_5.4-2.1.x-imx+gitAUTOINC+106305bdf4/tdx
I assume there must be quite easy method to change that file, and kindly ask if you can tell what
Br Vesa