Kconfig multiple set-value and priority

[loquat]

I would like to know the behavior when multiple Kconfig value settings are defined.
Settings are made in the following three places. (app directory)

Setting value of NRFX_GPIOTE_NUM_OF_EVT_HANDLERS
1. Kconfig
    config NRFX_GPIOTE_NUM_OF_EVT_HANDLERS
           default 2

2.CMakeLists.txt
set(CONFIG_NRFX_GPIOTE_NUM_OF_EVT_HANDLERS 4 CACHE INTERNAL "")

3.proj.conf
CONFIG_NRFX_GPIOTE_NUM_OF_EVT_HANDLERS=8

Please let me know those priority.

[Håkon Alseth]

Hi,

 

The value set in the application sets precedence:

https://docs.zephyrproject.org/3.1.0/build/kconfig/setting.html#the-initial-configuration

 

But; The CMakeLists.txt ordering also has an effect.

If this is your CMakeLists.txt:

cmake_minimum_required(VERSION 3.20.0)

set(CONFIG_NRFX_GPIOTE_NUM_OF_EVT_HANDLERS 4 CACHE INTERNAL "")

find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})

Then the ordering is:

1. CMakeLists.txt

2. prj.conf

3. Kconfig "default" keyword.

 

If you switch the lines, so that find_package is first:

cmake_minimum_required(VERSION 3.20.0)

find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})

set(CONFIG_NRFX_GPIOTE_NUM_OF_EVT_HANDLERS 4 CACHE INTERNAL "")

Then it will be:

1. prj.conf

2. CMakeLists.txt

3. Kconfig "default" keyword.

 

Kind regards,

Håkon

[loquat]

Realy?

I try on scan_adv project

Kconfig

source "Kconfig.zephyr"

config NRFX_GPIOTE_NUM_OF_EVT_HANDLERS
	default 2

CMakeLists.txt

cmake_minimum_required(VERSION 3.20.0)

set(CONFIG_NRFX_GPIOTE_NUM_OF_EVT_HANDLERS 4 CACHE INTERNAL "")

find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})

project(scan_adv)

FILE(GLOB app_sources src/*.c)
target_sources(app PRIVATE ${app_sources})

prj.conf

CONFIG_BT=y
CONFIG_BT_BROADCASTER=y
CONFIG_BT_OBSERVER=y
CONFIG_BT_DEBUG_LOG=y
CONFIG_NRFX_GPIOTE_NUM_OF_EVT_HANDLERS=8

The expected setting value is
CONFIG_NRFX_GPIOTE_NUM_OF_EVT_HANDLERS=8

but actually
CONFIG_NRFX_GPIOTE_NUM_OF_EVT_HANDLERS=4

what am i doing wrong?

[Håkon Alseth]

Hi,

 

You're right. It depends on where you place it in the CMakeLists.txt file.

If you place the set(..) before the find_package(..) line, the ordering will change to what you have now.

 

I'll update my original answer.

 

Kind regards,

Håkon

[loquat]

I want to set priority following,
1.prj.conf
2.CMakeLists.txt
3. Kconfig "default" keyword.

Where should I describe it in CMakeLists.txt, is it possible?

And one more question.

Myapps/Kconfig can not override default value?

I try,

MyApps/Kconfig
config BT_EXT_ADV_MAX_ADV_SET
    default 4

But, .config is
CONFIG_BT_EXT_ADV_MAX_ADV_SET=1
(BT_EXT_ADV_MAX_ADV_SET' default value defined '1' by zephyr/subsys/bluetooth/Kconfig.adv)

What I ended up wanting to do is load multiple proj.confs.
Is there any way?

[Håkon Alseth]

Hi,

 

loquat said:

I want to set priority following,
1.prj.conf
2.CMakeLists.txt
3. Kconfig "default" keyword.

Then you set it like I showed in the edited initial response:

cmake_minimum_required(VERSION 3.20.0)

find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})

...

set(CONFIG_NRFX_GPIOTE_NUM_OF_EVT_HANDLERS 4 CACHE INTERNAL "")

loquat said:

What I ended up wanting to do is load multiple proj.confs.

You can use "OVERLAY_CONFIG" variable to do this. Read about it here:

https://docs.zephyrproject.org/3.2.0/develop/application/index.html#important-build-system-variables

 

loquat said:

Myapps/Kconfig can not override default value?

No, you cannot redefine a already existing kconfig entry, but you can set a dependency on your own defined symbol:

depends on SYMBOL >= VALUE

https://docs.zephyrproject.org/3.2.0/build/kconfig/index.html

 

Kind regards,

Håkon

[loquat]

OK.Thanks.

I found that you can specify multiple files in the CONF_FILE variable.