Cleanest method to use Kconfig for application-specific configuration

[Matteo Elimo]

I would like to use Kconfig to manage application-specific configuration.

An example of what I want to achieve:

/* main.c */
#ifdef CONFIG_MYAPP_DO_THING
  DoTheThing();
#endif

/* prj.conf */
CONFIG_MYAPP_DO_THING=y

At the moment I am achieving this in a way that feels rather convoluted, and I am thinking that there is probably a cleaner way, but I cannot think of it.

This is what I am doing (my application is out-of-tree):

• the root of my repo has a Kconfig.app file that defines the options available, e.g:
  

  menuconfig MYAPP
  	bool "My Application"
  	default y
  	help
  	  My Application configuration
  
  if MYAPP
  
  config MYAPP_DO_THING
      bool "Enable doing the thing"
  
  endif #MYAPP

  
  
  
• the root of my repo has a zephyr/module.yml file:
  

  build:
    cmake: .
    kconfig: Kconfig.app

  
  
  
• the root of my repo has CMakeLists.txt that includes the following snippet: 
  

  # bring in modules (by telling the Zephyr build system where to look for a zephyr/modules.yml )
  set(ZEPHYR_EXTRA_MODULES ${CMAKE_CURRENT_LIST_DIR})
  

This makes my whole app look like a module to the Zephyr build system.

It seems like using Kconfig for your own application config would be the natural/idiomatic thing to do, so I would be surprised if there wasn't a simpler way to define custom KConfig options at the app level (e.g. a special name for a Kconfig file in the root that is implicitly brought in the build?), but I have not found it.

Is there something less convoluted I could do?

[Matteo Elimo]

Nevermind, I posted too soon =)

You don't need any of that, just:

• have a Kconfig file in your repo root
• make sure the Kconfig file starts by sourcing Kconfig.zephyr

I was missing the sourcing step, which made it not work and sent me down a rabbit hole of looking for complex solutions!

# /Kconfig
# this is all you need!
source "Kconfig.zephyr"

config MYAPP_DO_THING
    bool "Enable doing the thing"