arch(cmake): add native Kconfig support to cmake (#7934)

env_support/cmake/custom.cmake

@@ -8,6 +8,13 @@ option(LV_LVGL_H_INCLUDE_SIMPLE
 option(LV_CONF_INCLUDE_SIMPLE
        "Use #include \"lv_conf.h\" instead of #include \"../../lv_conf.h\"" ON)
 
+set(LV_KCONFIG_IGNORE "Don't use Kconfig. Kconfig is not used by default." ON)
+
+find_package(Python REQUIRED)
+
+option(LV_CONF_SKIP "Skip including lv_conf.h during configuration" OFF)
+option(LV_USE_KCONFIG "Use Kconfig to configure LVGL" OFF)
+
 # Option LV_CONF_PATH, which should be the path for lv_conf.h
 # If set parent path LV_CONF_DIR is added to includes
 if( LV_CONF_PATH )
@@ -27,12 +34,63 @@ file(GLOB_RECURSE THORVG_SOURCES ${LVGL_ROOT_DIR}/src/libs/thorvg/*.cpp ${LVGL_R
 add_library(lvgl ${SOURCES})
 add_library(lvgl::lvgl ALIAS lvgl)
 
+if ( LV_USE_KCONFIG )
+  # kconfig.cmake will generate the .config
+  # and autoconf.h, which will be used by lv_conf_kconfig.h
+  include(${CMAKE_CURRENT_LIST_DIR}/kconfig.cmake)
+
+  set(LV_KCONFIG_IGNORE OFF)
+  # Set the flag to specify we are using kconfig, needed for the
+  # generate_cmake_variables.py script
+  set(KCONFIG_FLAG --kconfig)
+  # If using Kconfig, we need to define additional definitions
+  set(PCPP_ADDITIONAL_DEFS "--defs" "LV_CONF_SKIP" "LV_CONF_KCONFIG_EXTERNAL_INCLUDE=\"${LV_CONF_KCONFIG_EXTERNAL_INCLUDE}\"")
+  else()
+  if (LV_CONF_PATH)
+    set(PCPP_ADDITIONAL_DEFS "--defs" "LV_CONF_PATH=\"${LV_CONF_PATH}\"")
+  endif()
+endif()
+
 target_compile_definitions(
   lvgl PUBLIC $<$<BOOL:${LV_LVGL_H_INCLUDE_SIMPLE}>:LV_LVGL_H_INCLUDE_SIMPLE>
-              $<$<BOOL:${LV_CONF_INCLUDE_SIMPLE}>:LV_CONF_INCLUDE_SIMPLE>)
+              $<$<BOOL:${LV_CONF_INCLUDE_SIMPLE}>:LV_CONF_INCLUDE_SIMPLE>
+              $<$<BOOL:${LV_KCONFIG_IGNORE}>:LV_KCONFIG_IGNORE>
+              $<$<BOOL:${LV_CONF_SKIP}>:LV_CONF_SKIP>
+)
+
+# Use the portable pcpp to preprocess lv_conf_internal.h
+execute_process(
+  COMMAND ${Python_EXECUTABLE} ${LVGL_ROOT_DIR}/scripts/preprocess_lv_conf_internal.py
+  --input ${LVGL_ROOT_DIR}/src/lv_conf_internal.h
+  --tmp_file ${CMAKE_CURRENT_BINARY_DIR}/tmp.h
+  --output ${CMAKE_CURRENT_BINARY_DIR}/lv_conf_expanded.h
+  ${PCPP_ADDITIONAL_DEFS}
+  --include ${LVGL_ROOT_DIR} ${LVGL_ROOT_DIR}/.. ${LVGL_ROOT_DIR}/src ${LV_CONF_DIR}
+  RESULT_VARIABLE ret
+)
+if(NOT "${ret}" STREQUAL "0")
+  message(FATAL_ERROR "preprocess_lv_conf_internal.py failed with return code: ${ret}")
+endif()
+
+# Convert the expanded lv_conf_expanded.h to cmake variables
+execute_process(
+  COMMAND ${Python_EXECUTABLE}
+    ${LVGL_ROOT_DIR}/scripts/generate_cmake_variables.py
+    --input ${CMAKE_CURRENT_BINARY_DIR}/lv_conf_expanded.h
+    --output ${CMAKE_CURRENT_BINARY_DIR}/lv_conf.cmake
+    ${KCONFIG_FLAG}
+    RESULT_VARIABLE ret
+)
+if(NOT "${ret}" STREQUAL "0")
+  message(FATAL_ERROR "generate_cmake_variables.py command failed with return code: ${ret}")
+endif()
+
+# This will set all CONFIG_LV_USE_* variables in cmake
+include(${CMAKE_BINARY_DIR}/lv_conf.cmake)
 
 # Add definition of LV_CONF_PATH only if needed
-if(LV_CONF_PATH)
+# Do not redefine it if already defined in tests/CMakeLists.txt
+if(LV_CONF_PATH AND NOT LV_BUILD_TEST)
   target_compile_definitions(lvgl PUBLIC LV_CONF_PATH=${LV_CONF_PATH})
 endif()
 

env_support/cmake/kconfig.cmake

@@ -0,0 +1,42 @@
+set(PROJECT_ROOT ${CMAKE_CURRENT_SOURCE_DIR})
+set(KCONFIG_ROOT ${CMAKE_CURRENT_SOURCE_DIR}/Kconfig)
+set(AUTOCONF_H ${CMAKE_CURRENT_BINARY_DIR}/autoconf.h)
+set(OUTPUT_DOTCONFIG ${CMAKE_CURRENT_SOURCE_DIR}/.config)
+set(KCONFIG_LIST_OUT ${CMAKE_CURRENT_BINARY_DIR}/kconfig_list)
+set(AUTO_CONF_DIR ${CMAKE_CURRENT_BINARY_DIR})
+
+# Check if the user want to use a defconfig, using the -DLV_DEFCONFIG_PATH option
+if(LV_DEFCONFIG_PATH)
+  set(DOTCONFIG ${LV_DEFCONFIG_PATH})
+else()
+  set(DOTCONFIG ${CMAKE_CURRENT_SOURCE_DIR}/.config)
+endif()
+
+execute_process(
+  COMMAND ${Python_EXECUTABLE}
+  ${LVGL_ROOT_DIR}/scripts/kconfig.py
+  ${LVGL_ROOT_DIR}/Kconfig
+  ${OUTPUT_DOTCONFIG}
+  ${AUTOCONF_H}
+  ${KCONFIG_LIST_OUT}
+  ${DOTCONFIG}
+  WORKING_DIRECTORY ${LVGL_ROOT_DIR}
+  # The working directory is set to the app dir such that the user
+  # can use relative paths in CONF_FILE, e.g. CONF_FILE=nrf5.conf
+  RESULT_VARIABLE ret
+)
+if(NOT "${ret}" STREQUAL "0")
+  message(FATAL_ERROR "command failed with return code: ${ret}")
+endif()
+
+# Re-configure (Re-execute all CMakeLists.txt code) when autoconf.h changes
+set_property(DIRECTORY APPEND PROPERTY CMAKE_CONFIGURE_DEPENDS ${AUTOCONF_H})
+
+# Set compile definitions for lvgl build
+add_compile_definitions(LV_CONF_KCONFIG_EXTERNAL_INCLUDE="${AUTOCONF_H}")
+# Set the variable that can be used by the CMakeLists.txt including this file
+set(LV_CONF_KCONFIG_EXTERNAL_INCLUDE "${AUTOCONF_H}")
+
+# Ensure LV_DEFCONFIG_PATH is not set in the path, to be able to call it without
+# the -DLV_DEFCONFIG_PATH after the first configuration, and to work with the .config
+unset(LV_DEFCONFIG_PATH CACHE)