move things around

firmware/lib/CMakeLists.txt

@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: Apache-2.0
+
+add_subdirectory_ifdef(CONFIG_CUSTOM custom)

firmware/lib/Kconfig

@@ -0,0 +1,8 @@
+# Copyright (c) 2021 Legrand North America, LLC.
+# SPDX-License-Identifier: Apache-2.0
+
+menu "Custom libraries"
+
+rsource "custom/Kconfig"
+
+endmenu

firmware/lib/custom/CMakeLists.txt

@@ -0,0 +1,5 @@
+# Copyright (c) 2021, Legrand North America, LLC.
+# SPDX-License-Identifier: Apache-2.0
+
+zephyr_library()
+zephyr_library_sources(custom.c)

firmware/lib/custom/Kconfig

@@ -0,0 +1,19 @@
+# Copyright (c) 2021, Legrand North America, LLC.
+# SPDX-License-Identifier: Apache-2.0
+
+config CUSTOM
+	bool "Support for custom library"
+	help
+	  This option enables the 'custom' library
+
+config CUSTOM_GET_VALUE_DEFAULT
+	int "custom_get_value() default return value"
+	depends on CUSTOM
+	default 0
+	help
+	  This option primarily exists as an example of a library Kconfig
+	  setting.
+
+	  This option specifies the value for custom_get_value() to return
+	  when the input parameter is zero. (Otherwise the function returns the
+	  input parameter value.)

firmware/lib/custom/custom.c

@@ -0,0 +1,12 @@
+/*
+ * Copyright (c) 2021, Legrand North America, LLC.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <app/lib/custom.h>
+
+int custom_get_value(int val)
+{
+	return (val != 0) ? val : CONFIG_CUSTOM_GET_VALUE_DEFAULT;
+}