ZephyrOS: how to add driver module to out of tree project

Question

I haven't found a definitive info on how to add a driver module to out-of-tree Zephyr project, so I will provide the answer by my own.

Answer 1

Changes:

CMakeLists.txt

+set(ZEPHYR_EXTRA_MODULES drivers/ololo)
find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})

prj.conf

+CONFIG_OLOLO=y

Kconfig

No changes

New files:

drivers/ololo/CMakeLists.txt

zephyr_library()
zephyr_library_sources_ifdef(CONFIG_OLOLO ololo.c)

drivers/ololo/Kconfig

menuconfig OLOLO
        bool "Ololo driver"
        default y
        select BLAH
        depends on MEH
        help
          Enable support for ololo driver

if OLOLO

module = OLOLO
module-str = ololo
source "subsys/logging/Kconfig.template.log_config"

endif

drivers/ololo/ololo.c

/* Code goes here */

drivers/ololo/zephyr/module.yml

build:
  cmake: .
  kconfig: Kconfig

Answer 2

To add a custom driver module that specifically includes system calls, one may want to take a look at teslabs/zds-2022-drivers-app lock module driver.