| The source tree contains the Device Tree Compiler (dtc) toolchain for |
| working with device tree source and binary files and also libfdt, a |
| utility library for reading and manipulating the binary format. |
| |
| DTC and LIBFDT are maintained by: |
| |
| David Gibson <david@gibson.dropbear.id.au> |
| Jon Loeliger <jdl@jdl.com> |
| |
| |
| Python library |
| -------------- |
| |
| A Python library is also available. To build this you will need to install |
| swig and Python development files. On Debian distributions: |
| |
| sudo apt-get install swig python-dev |
| |
| The library provides an Fdt class which you can use like this: |
| |
| $ PYTHONPATH=../pylibfdt python |
| >>> import libfdt |
| >>> fdt = libfdt.Fdt(open('test_tree1.dtb').read()) |
| >>> node = fdt.path_offset('/subnode@1') |
| >>> print node |
| 124 |
| >>> prop_offset = fdt.first_property_offset(node) |
| >>> prop = fdt.get_property_by_offset(prop_offset) |
| >>> print '%s=%r' % (prop.name, prop.value) |
| compatible=bytearray(b'subnode1\x00') |
| >>> print '%s=%s' % (prop.name, prop.value) |
| compatible=subnode1 |
| >>> node2 = fdt.path_offset('/') |
| >>> print fdt.getprop(node2, 'compatible') |
| test_tree1 |
| |
| You will find tests in tests/pylibfdt_tests.py showing how to use each |
| method. Help is available using the Python help command, e.g.: |
| |
| $ cd pylibfdt |
| $ python -c "import libfdt; help(libfdt)" |
| |
| If you add new features, please check code coverage: |
| |
| $ sudo apt-get install python-pip python-pytest |
| $ sudo pip install coverage |
| $ cd tests |
| $ coverage run pylibfdt_tests.py |
| $ coverage html |
| # Open 'htmlcov/index.html' in your browser |
| |
| |
| To install the library via the normal setup.py method, use: |
| |
| ./pylibfdt/setup.py [--prefix=/path/to/install_dir] |
| |
| If --prefix is not provided, the default prefix is used, typically '/usr' |
| or '/usr/local'. See Python's distutils documentation for details. You can |
| also install via the Makefile if you like, but the above is more common. |
| |
| To install both libfdt and pylibfdt you can use: |
| |
| make install [SETUP_PREFIX=/path/to/install_dir] \ |
| [PREFIX=/path/to/install_dir] |
| |
| To disable building the python library, even if swig and Python are available, |
| use: |
| |
| make NO_PYTHON=1 |
| |
| |
| More work remains to support all of libfdt, including access to numeric |
| values. |
| |
| |
| Tests |
| ----- |
| |
| Test files are kept in the tests/ directory. Use 'make check' to build and run |
| all tests. |
| |
| If you want to adjust a test file, be aware that tree_tree1.dts is compiled |
| and checked against a binary tree from assembler macros in trees.S. So |
| if you change that file you must change tree.S also. |
| |
| |
| Mailing list |
| ------------ |
| The following list is for discussion about dtc and libfdt implementation |
| mailto:devicetree-compiler@vger.kernel.org |
| |
| Core device tree bindings are discussed on the devicetree-spec list: |
| mailto:devicetree-spec@vger.kernel.org |