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-rw-r--r--Documentation/devicetree/index.rst59
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-Barebox specific devicetree bindings
-====================================
+Barebox devicetree handling and bindings
+========================================
+
+The preferred way of adding board support to barebox is to have devices
+on non-enumerable buses probed from device tree.
+barebox imports the Linux OpenFirmware ``of_*``-API functions for device tree
+parsing, which makes porting the device tree specific bits from device drivers
+very straight forward.
+
+Additionally, barebox has support for programmatically fixing up device trees
+it passes to the kernel, either directly via ``of_register_fixup`` or via device
+tree overlays.
+
+Upstream Device Trees
+---------------------
+
+barebox regularly synchronizes with the Linux kernel device tree definitions
+via the `kernel.org Split device-tree repository`_.
+They are located under the top-level ``dts/`` directory.
+
+Patches against ``dts/`` and its subdirectories are not accepted upstream.
+
+.. _kernel.org Split device-tree repository: https://git.kernel.org/pub/scm/linux/kernel/git/devicetree/devicetree-rebasing.git/
+
+barebox Device Trees
+--------------------
+
+For supporting architectures, barebox device trees are located in
+``arch/$ARCH/dts``. Usually the barebox ``board.dts`` imports the upstream
+device tree under ``dts/src/$ARCH`` with ``#include "$ARCH/board.dts"`` and
+then extends it with barebox-specifics like :ref:`barebox,state`,
+environment or boot-time device configuration.
+
+Device Tree Compiler
+--------------------
+
+barebox makes use of the ``dtc`` and ``fdtget`` and the underlying ``libfdt``
+from the `Device-Tree Compiler`_ project.
+
+.. _Device-Tree Compiler: https://git.kernel.org/pub/scm/utils/dtc/dtc.git
+
+These utilities are built as part of the barebox build process. Additionally,
+libfdt is compiled once more as part of the ``CONFIG_BOARD_ARM_GENERIC_DT``
+if selected.
+
+Steps to update ``scripts/dtc``:
+
+* Place a ``git-checkout`` of the upstream ``dtc`` directory in the parent
+ directory of your barebox ``git-checkout``.
+* Run ``scripts/dtc/update-dtc-source.sh`` from the top-level barebox directory.
+* Wait till ``dtc`` build, test, install and commit conclude.
+* Compile-test with ``CONFIG_BOARD_ARM_GENERIC_DT=y``.
+* If ``scripts/dtc/Makefile`` or barebox include file changes are necessary,
+ apply them manually in a commit preceding the ``dtc`` update.
+
+barebox-specific Bindings
+-------------------------
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