Lines Matching +full:dt +full:- +full:schema
1 .. SPDX-License-Identifier: GPL-2.0
3 Writing Devicetree Bindings in json-schema
6 Devicetree bindings are written using json-schema vocabulary. Schema files are
7 written in a JSON-compatible subset of YAML. YAML is used instead of JSON as it
11 Also see :ref:`example-schema`.
13 Schema Contents
14 ---------------
16 Each schema doc is a structured json-schema which is defined by a set of
17 top-level properties. Generally, there is one binding defined per file. The
18 top-level json-schema properties used are:
21 A json-schema unique identifier string. The string must be a valid
22 URI typically containing the binding's filename and path. For DT schema, it must
24 references to other files specified in schema "$ref" properties. A $ref value
27 components of the current schema file's '$id' value. A URL is used even for
30 $schema
31 Indicates the meta-schema the schema file adheres to.
34 A one-line description on the contents of the binding schema.
37 A DT specific property. Contains a list of email address(es)
41 Optional. A multi-line text block containing any detailed
47 Optional. A json-schema used to match nodes for applying the
48 schema. By default, without 'select', nodes are matched against their possible
49 compatible-string values or node name. Most bindings should not need select.
57 A set of sub-schema defining all the DT properties for the
58 binding. The exact schema syntax depends on whether properties are known,
59 common properties (e.g. 'interrupts') or are binding/vendor-specific
62 A property can also define a child DT node with child properties defined
65 For more details on properties sections, see 'Property Schema' section.
71 A list of DT properties from the 'properties' section that
80 Property Schema
81 ---------------
83 The 'properties' section of the schema contains all the DT properties for a
84 binding. Each property contains a set of constraints using json-schema
86 validation of DT files.
89 binding schema need to be defined such as how many values are valid or what
92 Vendor-specific properties will typically need more detailed schema. With the
96 The Devicetree schemas don't exactly match the YAML-encoded DT data produced by
98 boilerplate. The tools process the schema files to produce the final schema for
101 The default for arrays in json-schema is they are variable-sized and allow more
112 ------------
114 Use YAML coding style (two-space indentation). For DTS examples in the schema,
115 preferred is four-space indentation.
118 -------
123 The DT schema project must be installed in order to validate the DT schema
124 binding documents and validate DTS files using the DT schema. The DT schema
132 apt install swig python3-dev
134 Several executables (dt-doc-validate, dt-mk-schema, dt-validate) will be
142 The DT schema binding documents must be validated using the meta-schema (the
143 schema for the schema) to ensure they are both valid json-schema and valid
144 binding schema. All of the DT binding documents can be validated using the
149 In order to perform validation of DT source files, use the ``dtbs_check`` target::
153 Note that ``dtbs_check`` will skip any binding schema files with errors. It is
155 binding schema files.
161 It is also possible to run checks with a subset of matching schema files by
162 setting the ``DT_SCHEMA_FILES`` variable to a specific schema file or pattern.
166 make dt_binding_check DT_SCHEMA_FILES=trivial-devices.yaml
168 make dtbs_check DT_SCHEMA_FILES=trivial-devices.yaml
171 json-schema Resources
172 ---------------------
175 `JSON-Schema Specifications <http://json-schema.org/>`_
177 `Using JSON Schema Book <http://usingjsonschema.com/>`_
179 .. _example-schema:
181 Annotated Example Schema
182 ------------------------
184 Also available as a separate file: :download:`example-schema.yaml`
186 .. literalinclude:: example-schema.yaml