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# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
# Copyright 2018 Linaro Ltd.
%YAML 1.2
---
# All the top-level keys are standard json-schema keywords except for
# 'maintainers' and 'select'
# $id is a unique idenifier based on the filename. There may or may not be a
# file present at the URL.
$id: "http://devicetree.org/schemas/example-schema.yaml#"
# $schema is the meta-schema this schema should be validated with.
$schema: "http://devicetree.org/meta-schemas/core.yaml#"
title: An example schema annotated with jsonschema details
maintainers:
- Rob Herring <robh@kernel.org>
description: |
A more detailed multi-line description of the binding.
Details about the hardware device and any links to datasheets can go here.
Literal blocks are marked with the '|' at the beginning. The end is marked by
indentation less than the first line of the literal block. Lines also cannot
begin with a tab character.
select: false
# 'select' is a schema applied to a DT node to determine if this binding
# schema should be applied to the node. It is optional and by default the
# possible compatible strings are extracted and used to match.
# In this case, a 'false' schema will never match.
properties:
# A dictionary of DT properties for this binding schema
compatible:
# More complicated schema can use oneOf (XOR), anyOf (OR), or allOf (AND)
# to handle different conditions.
# In this case, it's needed to handle a variable number of values as there
# isn't another way to express a constraint of the last string value.
# The boolean schema must be a list of schemas.
oneOf:
- items:
# items is a list of possible values for the property. The number of
# values is determined by the number of elements in the list.
# Order in lists is significant, order in dicts is not
# Must be one of the 1st enums followed by the 2nd enum
#
# Each element in items should be 'enum' or 'const'
- enum:
- vendor,soc4-ip
- vendor,soc3-ip
- vendor,soc2-ip
- enum:
- vendor,soc1-ip
# additionalItems being false is implied
# minItems/maxItems equal to 2 is implied
- items:
# 'const' is just a special case of an enum with a single possible value
- const: vendor,soc1-ip
reg:
# The core schema already checks that reg values are numbers, so device
# specific schema don't need to do those checks.
# The description of each element defines the order and implicitly defines
# the number of reg entries.
items:
- description: core registers
- description: aux registers
# minItems/maxItems equal to 2 is implied
reg-names:
# The core schema enforces this is a string array
items:
- const: core
- const: aux
clocks:
# Cases that have only a single entry just need to express that with maxItems
maxItems: 1
description: bus clock
clock-names:
items:
- const: bus
interrupts:
# Either 1 or 2 interrupts can be present
minItems: 1
maxItems: 2
items:
- description: tx or combined interrupt
- description: rx interrupt
description:
A variable number of interrupts warrants a description of what conditions
affect the number of interrupts. Otherwise, descriptions on standard
properties are not necessary.
interrupt-names:
# minItems must be specified here because the default would be 2
minItems: 1
maxItems: 2
items:
- const: tx irq
- const: rx irq
# Property names starting with '#' must be quoted
'#interrupt-cells':
# A simple case where the value must always be '2'.
# The core schema handles that this must be a single integer.
const: 2
interrupt-controller: true
# The core checks this is a boolean, so just have to list it here to be
# valid for this binding.
clock-frequency:
# The type is set in the core schema. Per device schema only need to set
# constraints on the possible values.
minimum: 100
maximum: 400000
# The value that should be used if the property is not present
default: 200
foo-gpios:
maxItems: 1
description: A connection of the 'foo' gpio line.
vendor,int-property:
description: Vendor specific properties must have a description
# 'allOf' is the json-schema way of subclassing a schema. Here the base
# type schema is referenced and then additional constraints on the values
# are added.
allOf:
- $ref: /schemas/types.yaml#/definitions/uint32
- enum: [2, 4, 6, 8, 10]
vendor,bool-property:
description: Vendor specific properties must have a description
# boolean properties is one case where the json-schema 'type' keyword
# can be used directly
type: boolean
vendor,string-array-property:
description: Vendor specific properties should reference a type in the
core schema.
allOf:
- $ref: /schemas/types.yaml#/definitions/string-array
- items:
- enum: [ foo, bar ]
- enum: [ baz, boo ]
required:
- compatible
- reg
- interrupts
- interrupt-controller
examples:
# Examples are now compiled with dtc
- |
node@1000 {
compatible = "vendor,soc4-ip", "vendor,soc1-ip";
reg = <0x1000 0x80>,
<0x3000 0x80>;
reg-names = "core", "aux";
interrupts = <10>;
interrupt-controller;
};
|
