From 4f1674fc32224003931af4a74aa18168786ec9a2 Mon Sep 17 00:00:00 2001
From: Ulf Magnusson <ulfalizer@gmail.com>
Date: Sat, 27 Apr 2019 14:16:10 +0200
Subject: defconfig: Add script

Simple script for initializing the configuration from an existing
configuration file (usually a minimal configuration).

Just copying the minimal configuration to .config would usually work,
due to Kconfig semantics, but having it be a full configuration file
from the start might be handier and less confusing.
---
 README.rst   |  7 +++++++
 defconfig.py | 43 +++++++++++++++++++++++++++++++++++++++++++
 setup.py     |  2 ++
 3 files changed, 52 insertions(+)
 create mode 100755 defconfig.py

diff --git a/README.rst b/README.rst
index 638de30..46b236e 100644
--- a/README.rst
+++ b/README.rst
@@ -65,6 +65,8 @@ available in the C tools.
 
 - `savedefconfig <https://github.com/ulfalizer/Kconfiglib/blob/master/savedefconfig.py>`_
 
+- `defconfig <https://github.com/ulfalizer/Kconfiglib/blob/master/defconfig.py>`_
+
 - `alldefconfig <https://github.com/ulfalizer/Kconfiglib/blob/master/alldefconfig.py>`_
 
 - `allnoconfig <https://github.com/ulfalizer/Kconfiglib/blob/master/allnoconfig.py>`_
@@ -133,6 +135,11 @@ Getting started
 3. Generate an initial configuration with e.g. ``menuconfig`` or
    ``alldefconfig``. The configuration is saved as ``.config`` by default.
 
+   For more advanced projects, the ``defconfig`` utility can be used to
+   generate the initial configuration from an existing configuration file.
+   Usually, this existing configuration file would be a minimal configuration
+   file, as generated by e.g. ``savedefconfig``.
+
 4. Run ``genconfig`` to generate a header file. By default, it is saved as
    ``config.h``.
 
diff --git a/defconfig.py b/defconfig.py
new file mode 100755
index 0000000..7b02833
--- /dev/null
+++ b/defconfig.py
@@ -0,0 +1,43 @@
+#!/usr/bin/env python
+
+# Copyright (c) 2019, Ulf Magnusson
+# SPDX-License-Identifier: ISC
+
+"""
+Reads a specified configuration file, then writes a new configuration file.
+This can be used to initialize the configuration from e.g. an arch-specific
+configuration file. This input configuration file would usually be a minimal
+configuration file, as generated by e.g. savedefconfig.
+
+The default output filename is '.config'. A different filename can be passed in
+the KCONFIG_CONFIG environment variable.
+"""
+import argparse
+
+import kconfiglib
+
+
+def main():
+    parser = argparse.ArgumentParser(
+        formatter_class=argparse.RawDescriptionHelpFormatter,
+        description=__doc__)
+
+    parser.add_argument(
+        "--kconfig",
+        default="Kconfig",
+        help="Base Kconfig file (default: Kconfig)")
+
+    parser.add_argument(
+        "config",
+        metavar="CONFIGURATION",
+        help="Input configuration file")
+
+    args = parser.parse_args()
+
+    kconf = kconfiglib.Kconfig(args.kconfig)
+    kconf.load_config(args.config)
+    kconf.write_config()
+
+
+if __name__ == "__main__":
+    main()
diff --git a/setup.py b/setup.py
index b9e5e88..1660ccc 100644
--- a/setup.py
+++ b/setup.py
@@ -33,6 +33,7 @@ setuptools.setup(
         "oldconfig",
         "olddefconfig",
         "savedefconfig",
+        "defconfig",
         "alldefconfig",
         "allnoconfig",
         "allmodconfig",
@@ -50,6 +51,7 @@ setuptools.setup(
             "oldconfig = oldconfig:_main",
             "olddefconfig = olddefconfig:main",
             "savedefconfig = savedefconfig:main",
+            "defconfig = defconfig:main",
             "alldefconfig = alldefconfig:main",
             "allnoconfig = allnoconfig:main",
             "allmodconfig = allmodconfig:main",
-- 
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