Create a custom Yocto layer | ConnectCore MP25

Yocto Project allows developers to create custom layers to organize and manage modifications, custom recipes, and configurations. Creating a new layer in Yocto helps maintain a modular and organized structure for embedded Linux development. Layers allow for clean separation of vendor-specific changes, board support packages (BSPs), and custom application software.

Set up the environment

Before creating a new layer, ensure that you have set up your Digi Embedded Yocto environment.

If you haven’t done so, create a Digi Embedded Yocto project. See Create and build projects.
Go to your project folder and source the build environment:
```
$ cd <my-project>
$ source dey-setup-environment
```

Create the layer directory

Use the bitbake-layers tool to create a new layer at your desired path. For instance, to create a layer called meta-custom:

$ bitbake-layers create-layer /<yourpath>/meta-custom -a

This command:

Creates the basic layer structure at the given path, including an example recipe:

/<yourpath>/meta-custom/
├── conf
│  └── layer.conf
├── COPYING.MIT
├── README
└── recipes-example
    └── example
        └── example_0.1.bb

Automatically adds your new layer to your project’s conf/bblayers.conf file (option -a)
conf/bblayers.conf
```
BBLAYERS ?= " \
  [...]
  /<yourpath>/meta-custom \
  "
```

Layer priority

Each layer can define its priority using the BBFILE_PRIORITY_<layer-name> variable. Priorities allow managing conflicts between multiple layers providing the same recipe or configuration.

To set the priority for your custom layer, edit /<yourpath>/meta-custom/conf/layer.conf and add, for example:

/<yourpath>/meta-custom/conf/layer.conf

BBFILE_PRIORITY_meta-custom = "10"

A higher number means a higher priority. If another layer provides the same recipe but has a lower priority, the recipe from meta-custom will be used.

Create recipes

A recipe defines how a package is built. The command you used to create the new layer, already generated an example recipe called example.

Refer to the official Yocto documentation for information on creating recipes: https://docs.yoctoproject.org/dev-manual/new-recipe.html

Verify and test the layer

You can check if the new layer is recognized by running:

$ bitbake-layers show-layers