| 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 <loeliger@gmail.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 python3-dev | |
| The library provides an Fdt class which you can use like this: | |
| $ PYTHONPATH=../pylibfdt python3 | |
| >>> import libfdt | |
| >>> fdt = libfdt.Fdt(open('test_tree1.dtb', mode='rb').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=%s' % (prop.name, prop.as_str())) | |
| compatible=subnode1 | |
| >>> node2 = fdt.path_offset('/') | |
| >>> print(fdt.getprop(node2, 'compatible').as_str()) | |
| 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 | |
| $ python3 -c "import libfdt; help(libfdt)" | |
| If you add new features, please check code coverage: | |
| $ sudo apt-get install python3-coverage | |
| $ cd tests | |
| # It's just 'coverage' on most other distributions | |
| $ python3-coverage run pylibfdt_tests.py | |
| $ python3-coverage html | |
| # Open 'htmlcov/index.html' in your browser | |
| The library can be installed with pip from a local source tree: | |
| pip install . [--user|--prefix=/path/to/install_dir] | |
| Or directly from a remote git repo: | |
| pip install git+git://git.kernel.org/pub/scm/utils/dtc/dtc.git@main | |
| The install depends on libfdt shared library being installed on the host system | |
| first. Generally, using --user or --prefix is not necessary and pip will use the | |
| default location for the Python installation which varies if the user is root or | |
| not. | |
| You can also install everything via make if you like, but pip is recommended. | |
| To install both libfdt and pylibfdt you can use: | |
| make install [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. | |
| Adding a new function to libfdt.h | |
| --------------------------------- | |
| The shared library uses libfdt/version.lds to list the exported functions, so | |
| add your new function there. Check that your function works with pylibfdt. If | |
| it cannot be supported, put the declaration in libfdt.h behind #ifndef SWIG so | |
| that swig ignores it. | |
| 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 |