devicetree/bindings/example-schema.yaml

1 # SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
4 ---
5 # All the top-level keys are standard json-schema keywords except for
8 # $id is a unique identifier based on the filename. There may or may not be a
10 $id: http://devicetree.org/schemas/example-schema.yaml#
11 # $schema is the meta-schema this schema should be validated with.
12 $schema: http://devicetree.org/meta-schemas/core.yaml#
17   - Rob Herring <robh@kernel.org>
20   A more detailed multi-line description of the binding.
26   begin with a tab character.
29   # 'select' is a schema applied to a DT node to determine if this binding
30   # schema should be applied to the node. It is optional and by default the
33   # In this case, a 'false' schema will never match.
36   # A dictionary of DT properties for this binding schema
40     # In this case, it's needed to handle a variable number of values as there
41     # isn't another way to express a constraint of the last string value.
42     # The boolean schema must be a list of schemas.
44       - items:
45           # items is a list of possible values for the property. The number of
51           - enum:
52               - vendor,soc4-ip
53               - vendor,soc3-ip
54               - vendor,soc2-ip
55           - const: vendor,soc1-ip
58       - items:
59           # 'const' is just a special case of an enum with a single possible value
60           - const: vendor,soc1-ip
68       - description: core registers
69       - description: aux registers
72   reg-names:
73     # The core schema enforces this (*-names) is a string array
75       - const: core
76       - const: aux
79     # Cases that have only a single entry just need to express that with maxItems
81     description: bus clock. A description is only needed for a single item if
83       The items should have a fixed order, so pattern matching names are
86   clock-names:
87     # For single-entry lists in clocks, resets etc., the xxx-names often do not
89     # just skip the xxx-names.
91       - const: bus
97       - description: tx or combined interrupt
98       - description: rx interrupt
100       A variable number of interrupts warrants a description of what conditions
103       The items should have a fixed order, so pattern matching names are
106   interrupt-names:
110       - const: tx irq
111       - const: rx irq
113   # Property names starting with '#' must be quoted
114   '#interrupt-cells':
115     # A simple case where the value must always be '2'.
116     # The core schema handles that this must be a single integer.
119   interrupt-controller: true
120     # The core checks this is a boolean, so just have to list it here to be
123   clock-frequency:
124     # The type is set in the core schema. Per-device schema only need to set
128     # The value that should be used if the property is not present
131   foo-gpios:
133     description: A connection of the 'foo' gpio line.
135   # *-supply is always a single phandle, so nothing more to define.
136   foo-supply: true
138   # Vendor-specific properties
140   # Vendor-specific properties have slightly different schema requirements than
141   # common properties. They must have at least a type definition and
143   vendor,int-property:
144     description: Vendor-specific properties must have a description
148   vendor,bool-property:
149     description: Vendor-specific properties must have a description. Boolean
150       properties are one case where the json-schema 'type' keyword can be used
154   vendor,string-array-property:
155     description: Vendor-specific properties should reference a type in the
157     $ref: /schemas/types.yaml#/definitions/string-array
159       - enum: [foo, bar]
160       - enum: [baz, boo]
162   vendor,property-in-standard-units-microvolt:
163     description: Vendor-specific properties having a standard unit suffix
164       don't need a type.
167   vendor,int-array-variable-length-and-constrained-values:
170     $ref: /schemas/types.yaml#/definitions/uint32-array
177   child-node:
178     description: Child nodes are just another property from a json-schema
181     # Child nodes also need additionalProperties or unevaluatedProperties
184       vendor,a-child-node-property:
185         description: Child node properties have all the same schema
190       - vendor,a-child-node-property
194   # 'vendor,bool-property' is only allowed when 'vendor,string-array-property'
196   vendor,bool-property: [ 'vendor,string-array-property' ]
199   vendor,string-array-property: [ 'vendor,bool-property' ]
202   - compatible
203   - reg
204   - interrupts
205   - interrupt-controller
207 # if/then schema can be used to handle conditions on a property affecting
208 # another property. A typical case is a specific 'compatible' value changes the
216   - if:
220             const: vendor,soc2-ip
223         - foo-supply
225       # If otherwise the property is not allowed:
227         foo-supply: false
230   - if:
232         - vendor,bool-property
235         vendor,int-property:
239 # present are allowed. There's a few common properties such as 'status' and
240 # 'pinctrl-*' which are added automatically by the tooling.
245 # appear, "unevaluatedProperties: false" could be used.  A typical example is
252   # Examples have a default #address-cells and #size-cells value of 1. This can
253   # be overridden or an appropriate parent bus node should be shown (such as on
256   # Any includes used have to be explicitly included. Use 4-space indentation.
257   - |
258     node@1000 {
259         compatible = "vendor,soc4-ip", "vendor,soc1-ip";
262         reg-names = "core", "aux";
264         interrupt-controller;