1The source tree contains the Device Tree Compiler (dtc) toolchain for
2working with device tree source and binary files and also libfdt, a
3utility library for reading and manipulating the binary format.
4
5DTC and LIBFDT are maintained by:
6
7David Gibson <david@gibson.dropbear.id.au>
8Jon Loeliger <jdl@jdl.com>
9
10
11Python library
12--------------
13
14A Python library is also available. To build this you will need to install
15swig and Python development files. On Debian distributions:
16
17   sudo apt-get install swig python3-dev
18
19The library provides an Fdt class which you can use like this:
20
21$ PYTHONPATH=../pylibfdt python3
22>>> import libfdt
23>>> fdt = libfdt.Fdt(open('test_tree1.dtb', mode='rb').read())
24>>> node = fdt.path_offset('/subnode@1')
25>>> print(node)
26124
27>>> prop_offset = fdt.first_property_offset(node)
28>>> prop = fdt.get_property_by_offset(prop_offset)
29>>> print('%s=%s' % (prop.name, prop.as_str()))
30compatible=subnode1
31>>> node2 = fdt.path_offset('/')
32>>> print(fdt.getprop(node2, 'compatible').as_str())
33test_tree1
34
35You will find tests in tests/pylibfdt_tests.py showing how to use each
36method. Help is available using the Python help command, e.g.:
37
38    $ cd pylibfdt
39    $ python3 -c "import libfdt; help(libfdt)"
40
41If you add new features, please check code coverage:
42
43    $ sudo apt-get install python3-coverage
44    $ cd tests
45    # It's just 'coverage' on most other distributions
46    $ python3-coverage run pylibfdt_tests.py
47    $ python3-coverage html
48    # Open 'htmlcov/index.html' in your browser
49
50
51To install the library via the normal setup.py method, use:
52
53    ./pylibfdt/setup.py install [--prefix=/path/to/install_dir]
54
55If --prefix is not provided, the default prefix is used, typically '/usr'
56or '/usr/local'. See Python's distutils documentation for details. You can
57also install via the Makefile if you like, but the above is more common.
58
59To install both libfdt and pylibfdt you can use:
60
61    make install [SETUP_PREFIX=/path/to/install_dir] \
62            [PREFIX=/path/to/install_dir]
63
64To disable building the python library, even if swig and Python are available,
65use:
66
67    make NO_PYTHON=1
68
69
70More work remains to support all of libfdt, including access to numeric
71values.
72
73
74Tests
75-----
76
77Test files are kept in the tests/ directory. Use 'make check' to build and run
78all tests.
79
80If you want to adjust a test file, be aware that tree_tree1.dts is compiled
81and checked against a binary tree from assembler macros in trees.S. So
82if you change that file you must change tree.S also.
83
84
85Mailing list
86------------
87The following list is for discussion about dtc and libfdt implementation
88mailto:devicetree-compiler@vger.kernel.org
89
90Core device tree bindings are discussed on the devicetree-spec list:
91mailto:devicetree-spec@vger.kernel.org
92