summaryrefslogtreecommitdiffstats
path: root/Documentation/devicetree/writing-schema.md
diff options
context:
space:
mode:
Diffstat (limited to 'Documentation/devicetree/writing-schema.md')
-rw-r--r--Documentation/devicetree/writing-schema.md130
1 files changed, 0 insertions, 130 deletions
diff --git a/Documentation/devicetree/writing-schema.md b/Documentation/devicetree/writing-schema.md
deleted file mode 100644
index dc032db36262..000000000000
--- a/Documentation/devicetree/writing-schema.md
+++ /dev/null
@@ -1,130 +0,0 @@
-# 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
-considered more human readable and has some advantages such as allowing
-comments (Prefixed with '#').
-
-## Schema Contents
-
-Each schema doc is a structured json-schema which is defined by a set of
-top-level properties. Generally, there is one binding defined per file. The
-top-level json-schema properties used are:
-
-- __$id__ - A json-schema unique identifier string. The string must be a valid
-URI typically containing the binding's filename and path. For DT schema, it must
-begin with "http://devicetree.org/schemas/". The URL is used in constructing
-references to other files specified in schema "$ref" properties. A $ref values
-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.
-
-- __$schema__ - Indicates the meta-schema the schema file adheres to.
-
-- __title__ - A one line description on the contents of the binding schema.
-
-- __maintainers__ - A DT specific property. Contains a list of email address(es)
-for maintainers of this binding.
-
-- __description__ - Optional. A multi-line text block containing any detailed
-information about this binding. It should contain things such as what the block
-or device does, standards the device conforms to, and links to datasheets for
-more information.
-
-- __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.
-
-- __allOf__ - Optional. A list of other schemas to include. This is used to
-include other schemas the binding conforms to. This may be schemas for a
-particular class of devices such as I2C or SPI controllers.
-
-- __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.
-
- A property can also define a child DT node with child properties defined
-under it.
-
- For more details on properties sections, see 'Property Schema' section.
-
-- __patternProperties__ - Optional. Similar to 'properties', but names are regex.
-
-- __required__ - A list of DT properties from the 'properties' section that
-must always be present.
-
-- __examples__ - Optional. A list of one or more DTS hunks implementing the
-binding. Note: YAML doesn't allow leading tabs, so spaces must be used instead.
-
-Unless noted otherwise, all properties are required.
-
-## 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
-validation of DT files.
-
-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
-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
-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
-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
-number of entries in an 'items' list.
-
-The YAML Devicetree format also makes all string values an array and scalar
-values a matrix (in order to define groupings) even when only a single value
-is present. Single entries in schemas are fixed up to match this encoding.
-
-## Testing
-
-### Dependencies
-
-The DT schema project must be installed in order to validate the DT schema
-binding documents and validate DTS files using the DT schema. The DT schema
-project can be installed with pip:
-
-`pip3 install git+https://github.com/devicetree-org/dt-schema.git@master`
-
-dtc must also be built with YAML output support enabled. This requires that
-libyaml and its headers be installed on the host system.
-
-### Running checks
-
-The DT schema binding documents must be validated using the meta-schema (the
-schema for the schema) to ensure they are both valid json-schema and valid
-binding schema. All of the DT binding documents can be validated using the
-`dt_binding_check` target:
-
-`make dt_binding_check`
-
-In order to perform validation of DT source files, use the `dtbs_check` target:
-
-`make dtbs_check`
-
-This will first run the `dt_binding_check` which generates the processed schema.
-
-It is also possible to run checks with a single schema file by setting the
-'DT_SCHEMA_FILES' variable to a specific schema file.
-
-`make dtbs_check DT_SCHEMA_FILES=Documentation/devicetree/bindings/trivial-devices.yaml`
-
-
-## json-schema Resources
-
-[JSON-Schema Specifications](http://json-schema.org/)
-
-[Using JSON Schema Book](http://usingjsonschema.com/)