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Diffstat (limited to 'dts/Bindings/writing-schema.rst')
| -rw-r--r-- | dts/Bindings/writing-schema.rst | 29 |
1 files changed, 15 insertions, 14 deletions
diff --git a/dts/Bindings/writing-schema.rst b/dts/Bindings/writing-schema.rst index 23d6579aea..ea21c72aeb 100644 --- a/dts/Bindings/writing-schema.rst +++ b/dts/Bindings/writing-schema.rst @@ -4,7 +4,7 @@ Writing Devicetree Bindings in json-schema ========================================== Devicetree bindings are written using json-schema vocabulary. Schema files are -written in a JSON compatible subset of YAML. YAML is used instead of JSON as it +written in a JSON-compatible subset of YAML. YAML is used instead of JSON as it is considered more human readable and has some advantages such as allowing comments (Prefixed with '#'). @@ -22,16 +22,16 @@ $id URI typically containing the binding's filename and path. For DT schema, it must begin with "http://devicetree.org/schemas/". The URL is used in constructing references to other files specified in schema "$ref" properties. A $ref value - with a leading '/' will have the hostname prepended. A $ref value a relative - path or filename only will be prepended with the hostname and path components - of the current schema file's '$id' value. A URL is used even for local files, - but there may not actually be files present at those locations. + with a leading '/' will have the hostname prepended. A $ref value with only a + relative path or filename will be prepended with the hostname and path + components of the current schema file's '$id' value. A URL is used even for + local files, but there may not actually be files present at those locations. $schema Indicates the meta-schema the schema file adheres to. title - A one line description on the contents of the binding schema. + A one-line description on the contents of the binding schema. maintainers A DT specific property. Contains a list of email address(es) @@ -45,8 +45,8 @@ description select Optional. A json-schema used to match nodes for applying the - schema. By default without 'select', nodes are matched against their possible - compatible string values or node name. Most bindings should not need select. + schema. By default, without 'select', nodes are matched against their possible + compatible-string values or node name. Most bindings should not need select. allOf Optional. A list of other schemas to include. This is used to @@ -56,7 +56,8 @@ allOf properties A set of sub-schema defining all the DT properties for the binding. The exact schema syntax depends on whether properties are known, - common properties (e.g. 'interrupts') or are binding/vendor specific properties. + common properties (e.g. 'interrupts') or are binding/vendor-specific + properties. A property can also define a child DT node with child properties defined under it. @@ -81,23 +82,23 @@ Property Schema The 'properties' section of the schema contains all the DT properties for a binding. Each property contains a set of constraints using json-schema -vocabulary for that property. The properties schemas are what is used for +vocabulary for that property. The properties schemas are what are used for validation of DT files. -For common properties, only additional constraints not covered by the common +For common properties, only additional constraints not covered by the common, binding schema need to be defined such as how many values are valid or what possible values are valid. -Vendor specific properties will typically need more detailed schema. With the +Vendor-specific properties will typically need more detailed schema. With the exception of boolean properties, they should have a reference to a type in schemas/types.yaml. A "description" property is always required. -The Devicetree schemas don't exactly match the YAML encoded DT data produced by +The Devicetree schemas don't exactly match the YAML-encoded DT data produced by dtc. They are simplified to make them more compact and avoid a bunch of boilerplate. The tools process the schema files to produce the final schema for validation. There are currently 2 transformations the tools perform. -The default for arrays in json-schema is they are variable sized and allow more +The default for arrays in json-schema is they are variable-sized and allow more entries than explicitly defined. This can be restricted by defining 'minItems', 'maxItems', and 'additionalItems'. However, for DeviceTree Schemas, a fixed size is desired in most cases, so these properties are added based on the |