1 # SPDX-License-Identifier: (GPL-2.0-only OR BS 1 # SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
2 # Copyright 2018 Linaro Ltd. 2 # Copyright 2018 Linaro Ltd.
3 %YAML 1.2 3 %YAML 1.2
4 --- 4 ---
5 # All the top-level keys are standard json-sch 5 # All the top-level keys are standard json-schema keywords except for
6 # 'maintainers' and 'select' 6 # 'maintainers' and 'select'
7 7
8 # $id is a unique identifier based on the file 8 # $id is a unique identifier based on the filename. There may or may not be a
9 # file present at the URL. 9 # file present at the URL.
10 $id: http://devicetree.org/schemas/example-sch !! 10 $id: "http://devicetree.org/schemas/example-schema.yaml#"
11 # $schema is the meta-schema this schema shoul 11 # $schema is the meta-schema this schema should be validated with.
12 $schema: http://devicetree.org/meta-schemas/co !! 12 $schema: "http://devicetree.org/meta-schemas/core.yaml#"
13 13
14 title: An Example Device !! 14 title: An example schema annotated with jsonschema details
15 15
16 maintainers: 16 maintainers:
17 - Rob Herring <robh@kernel.org> 17 - Rob Herring <robh@kernel.org>
18 18
19 description: | 19 description: |
20 A more detailed multi-line description of th 20 A more detailed multi-line description of the binding.
21 21
22 Details about the hardware device and any li 22 Details about the hardware device and any links to datasheets can go here.
23 23
24 Literal blocks are marked with the '|' at th 24 Literal blocks are marked with the '|' at the beginning. The end is marked by
25 indentation less than the first line of the 25 indentation less than the first line of the literal block. Lines also cannot
26 begin with a tab character. 26 begin with a tab character.
27 27
28 select: false 28 select: false
29 # 'select' is a schema applied to a DT node 29 # 'select' is a schema applied to a DT node to determine if this binding
30 # schema should be applied to the node. It i 30 # schema should be applied to the node. It is optional and by default the
31 # possible compatible strings are extracted 31 # possible compatible strings are extracted and used to match.
32 32
33 # In this case, a 'false' schema will never 33 # In this case, a 'false' schema will never match.
34 34
35 properties: 35 properties:
36 # A dictionary of DT properties for this bin 36 # A dictionary of DT properties for this binding schema
37 compatible: 37 compatible:
38 # More complicated schema can use oneOf (X 38 # More complicated schema can use oneOf (XOR), anyOf (OR), or allOf (AND)
39 # to handle different conditions. 39 # to handle different conditions.
40 # In this case, it's needed to handle a va 40 # In this case, it's needed to handle a variable number of values as there
41 # isn't another way to express a constrain 41 # isn't another way to express a constraint of the last string value.
42 # The boolean schema must be a list of sch 42 # The boolean schema must be a list of schemas.
43 oneOf: 43 oneOf:
44 - items: 44 - items:
45 # items is a list of possible values 45 # items is a list of possible values for the property. The number of
46 # values is determined by the number 46 # values is determined by the number of elements in the list.
47 # Order in lists is significant, ord 47 # Order in lists is significant, order in dicts is not
48 # Must be one of the 1st enums follo 48 # Must be one of the 1st enums followed by the 2nd enum
49 # 49 #
50 # Each element in items should be 'e 50 # Each element in items should be 'enum' or 'const'
51 - enum: 51 - enum:
52 - vendor,soc4-ip 52 - vendor,soc4-ip
53 - vendor,soc3-ip 53 - vendor,soc3-ip
54 - vendor,soc2-ip 54 - vendor,soc2-ip
55 - const: vendor,soc1-ip !! 55 - enum:
>> 56 - vendor,soc1-ip
56 # additionalItems being false is impli 57 # additionalItems being false is implied
57 # minItems/maxItems equal to 2 is impl 58 # minItems/maxItems equal to 2 is implied
58 - items: 59 - items:
59 # 'const' is just a special case of 60 # 'const' is just a special case of an enum with a single possible value
60 - const: vendor,soc1-ip 61 - const: vendor,soc1-ip
61 62
62 reg: 63 reg:
63 # The core schema already checks that reg 64 # The core schema already checks that reg values are numbers, so device
64 # specific schema don't need to do those c 65 # specific schema don't need to do those checks.
65 # The description of each element defines 66 # The description of each element defines the order and implicitly defines
66 # the number of reg entries. 67 # the number of reg entries.
67 items: 68 items:
68 - description: core registers 69 - description: core registers
69 - description: aux registers 70 - description: aux registers
70 # minItems/maxItems equal to 2 is implied 71 # minItems/maxItems equal to 2 is implied
71 72
72 reg-names: 73 reg-names:
73 # The core schema enforces this (*-names) 74 # The core schema enforces this (*-names) is a string array
74 items: 75 items:
75 - const: core 76 - const: core
76 - const: aux 77 - const: aux
77 78
78 clocks: 79 clocks:
79 # Cases that have only a single entry just 80 # Cases that have only a single entry just need to express that with maxItems
80 maxItems: 1 81 maxItems: 1
81 description: bus clock. A description is o 82 description: bus clock. A description is only needed for a single item if
82 there's something unique to add. 83 there's something unique to add.
83 The items should have a fixed order, so <<
84 discouraged. <<
85 84
86 clock-names: 85 clock-names:
87 # For single-entry lists in clocks, resets <<
88 # bring any value, especially if they copy <<
89 # just skip the xxx-names. <<
90 items: 86 items:
91 - const: bus 87 - const: bus
92 88
93 interrupts: 89 interrupts:
94 # Either 1 or 2 interrupts can be present 90 # Either 1 or 2 interrupts can be present
95 minItems: 1 91 minItems: 1
>> 92 maxItems: 2
96 items: 93 items:
97 - description: tx or combined interrupt 94 - description: tx or combined interrupt
98 - description: rx interrupt 95 - description: rx interrupt
99 description: 96 description:
100 A variable number of interrupts warrants 97 A variable number of interrupts warrants a description of what conditions
101 affect the number of interrupts. Otherwi 98 affect the number of interrupts. Otherwise, descriptions on standard
102 properties are not necessary. 99 properties are not necessary.
103 The items should have a fixed order, so <<
104 discouraged. <<
105 100
106 interrupt-names: 101 interrupt-names:
107 # minItems must be specified here because 102 # minItems must be specified here because the default would be 2
108 minItems: 1 103 minItems: 1
>> 104 maxItems: 2
109 items: 105 items:
110 - const: tx irq 106 - const: tx irq
111 - const: rx irq 107 - const: rx irq
112 108
113 # Property names starting with '#' must be q 109 # Property names starting with '#' must be quoted
114 '#interrupt-cells': 110 '#interrupt-cells':
115 # A simple case where the value must alway 111 # A simple case where the value must always be '2'.
116 # The core schema handles that this must b 112 # The core schema handles that this must be a single integer.
117 const: 2 113 const: 2
118 114
119 interrupt-controller: true 115 interrupt-controller: true
120 # The core checks this is a boolean, so ju 116 # The core checks this is a boolean, so just have to list it here to be
121 # valid for this binding. 117 # valid for this binding.
122 118
123 clock-frequency: 119 clock-frequency:
124 # The type is set in the core schema. Per- !! 120 # The type is set in the core schema. Per device schema only need to set
125 # constraints on the possible values. 121 # constraints on the possible values.
126 minimum: 100 122 minimum: 100
127 maximum: 400000 123 maximum: 400000
128 # The value that should be used if the pro 124 # The value that should be used if the property is not present
129 default: 200 125 default: 200
130 126
131 foo-gpios: 127 foo-gpios:
132 maxItems: 1 128 maxItems: 1
133 description: A connection of the 'foo' gpi 129 description: A connection of the 'foo' gpio line.
134 130
135 # *-supply is always a single phandle, so no 131 # *-supply is always a single phandle, so nothing more to define.
136 foo-supply: true 132 foo-supply: true
137 133
138 # Vendor-specific properties !! 134 # Vendor specific properties
139 # 135 #
140 # Vendor-specific properties have slightly d !! 136 # Vendor specific properties have slightly different schema requirements than
141 # common properties. They must have at least 137 # common properties. They must have at least a type definition and
142 # 'description'. 138 # 'description'.
143 vendor,int-property: 139 vendor,int-property:
144 description: Vendor-specific properties mu !! 140 description: Vendor specific properties must have a description
145 $ref: /schemas/types.yaml#/definitions/uin !! 141 # 'allOf' is the json-schema way of subclassing a schema. Here the base
146 enum: [2, 4, 6, 8, 10] !! 142 # type schema is referenced and then additional constraints on the values
>> 143 # are added.
>> 144 allOf:
>> 145 - $ref: /schemas/types.yaml#/definitions/uint32
>> 146 - enum: [2, 4, 6, 8, 10]
147 147
148 vendor,bool-property: 148 vendor,bool-property:
149 description: Vendor-specific properties mu !! 149 description: Vendor specific properties must have a description. Boolean
150 properties are one case where the json-s 150 properties are one case where the json-schema 'type' keyword can be used
151 directly. 151 directly.
152 type: boolean 152 type: boolean
153 153
154 vendor,string-array-property: 154 vendor,string-array-property:
155 description: Vendor-specific properties sh !! 155 description: Vendor specific properties should reference a type in the
156 core schema. 156 core schema.
157 $ref: /schemas/types.yaml#/definitions/str !! 157 allOf:
158 items: !! 158 - $ref: /schemas/types.yaml#/definitions/string-array
159 - enum: [foo, bar] !! 159 - items:
160 - enum: [baz, boo] !! 160 - enum: [ foo, bar ]
>> 161 - enum: [ baz, boo ]
161 162
162 vendor,property-in-standard-units-microvolt: 163 vendor,property-in-standard-units-microvolt:
163 description: Vendor-specific properties ha !! 164 description: Vendor specific properties having a standard unit suffix
164 don't need a type. 165 don't need a type.
165 enum: [ 100, 200, 300 ] 166 enum: [ 100, 200, 300 ]
166 167
167 vendor,int-array-variable-length-and-constra <<
168 description: Array might define what type <<
169 their range). <<
170 $ref: /schemas/types.yaml#/definitions/uin <<
171 minItems: 2 <<
172 maxItems: 3 <<
173 items: <<
174 minimum: 0 <<
175 maximum: 8 <<
176 <<
177 child-node: 168 child-node:
178 description: Child nodes are just another 169 description: Child nodes are just another property from a json-schema
179 perspective. 170 perspective.
180 type: object # DT nodes are json objects 171 type: object # DT nodes are json objects
181 # Child nodes also need additionalProperti <<
182 additionalProperties: false <<
183 properties: 172 properties:
184 vendor,a-child-node-property: 173 vendor,a-child-node-property:
185 description: Child node properties hav 174 description: Child node properties have all the same schema
186 requirements. 175 requirements.
187 type: boolean 176 type: boolean
188 177
189 required: 178 required:
190 - vendor,a-child-node-property 179 - vendor,a-child-node-property
191 180
192 # Describe the relationship between different 181 # Describe the relationship between different properties
193 dependencies: 182 dependencies:
194 # 'vendor,bool-property' is only allowed whe 183 # 'vendor,bool-property' is only allowed when 'vendor,string-array-property'
195 # is present 184 # is present
196 vendor,bool-property: [ 'vendor,string-array !! 185 vendor,bool-property: [ vendor,string-array-property ]
197 # Expressing 2 properties in both orders mea 186 # Expressing 2 properties in both orders means all of the set of properties
198 # must be present or none of them. 187 # must be present or none of them.
199 vendor,string-array-property: [ 'vendor,bool !! 188 vendor,string-array-property: [ vendor,bool-property ]
200 189
201 required: 190 required:
202 - compatible 191 - compatible
203 - reg 192 - reg
204 - interrupts 193 - interrupts
205 - interrupt-controller 194 - interrupt-controller
206 195
207 # if/then schema can be used to handle conditi 196 # if/then schema can be used to handle conditions on a property affecting
208 # another property. A typical case is a specif 197 # another property. A typical case is a specific 'compatible' value changes the
209 # constraints on other properties. 198 # constraints on other properties.
210 # 199 #
211 # For multiple 'if' schema, group them under a 200 # For multiple 'if' schema, group them under an 'allOf'.
212 # 201 #
213 # If the conditionals become too unweldy, then 202 # If the conditionals become too unweldy, then it may be better to just split
214 # the binding into separate schema documents. 203 # the binding into separate schema documents.
215 allOf: !! 204 if:
216 - if: !! 205 properties:
217 properties: !! 206 compatible:
218 compatible: !! 207 contains:
219 contains: !! 208 const: vendor,soc2-ip
220 const: vendor,soc2-ip !! 209 then:
221 then: !! 210 required:
222 required: !! 211 - foo-supply
223 - foo-supply <<
224 else: <<
225 # If otherwise the property is not allow <<
226 properties: <<
227 foo-supply: false <<
228 # Altering schema depending on presence of p <<
229 # dependencies (see above), however some adj <<
230 - if: <<
231 required: <<
232 - vendor,bool-property <<
233 then: <<
234 properties: <<
235 vendor,int-property: <<
236 enum: [2, 4, 6] <<
237 212
238 # Ideally, the schema should have this line ot 213 # Ideally, the schema should have this line otherwise any other properties
239 # present are allowed. There's a few common pr 214 # present are allowed. There's a few common properties such as 'status' and
240 # 'pinctrl-*' which are added automatically by 215 # 'pinctrl-*' which are added automatically by the tooling.
241 # 216 #
242 # This can't be used in cases where another sc 217 # This can't be used in cases where another schema is referenced
243 # (i.e. allOf: [{$ref: ...}]). 218 # (i.e. allOf: [{$ref: ...}]).
244 # If and only if another schema is referenced <<
245 # appear, "unevaluatedProperties: false" could <<
246 # an I2C controller where no name pattern matc <<
247 additionalProperties: false 219 additionalProperties: false
248 220
249 examples: 221 examples:
250 # Examples are now compiled with dtc and val 222 # Examples are now compiled with dtc and validated against the schemas
251 # 223 #
252 # Examples have a default #address-cells and 224 # Examples have a default #address-cells and #size-cells value of 1. This can
253 # be overridden or an appropriate parent bus 225 # be overridden or an appropriate parent bus node should be shown (such as on
254 # i2c buses). 226 # i2c buses).
255 # 227 #
256 # Any includes used have to be explicitly in !! 228 # Any includes used have to be explicitly included.
257 - | 229 - |
258 node@1000 { 230 node@1000 {
259 compatible = "vendor,soc4-ip", "vendor !! 231 compatible = "vendor,soc4-ip", "vendor,soc1-ip";
260 reg = <0x1000 0x80>, !! 232 reg = <0x1000 0x80>,
261 <0x3000 0x80>; !! 233 <0x3000 0x80>;
262 reg-names = "core", "aux"; !! 234 reg-names = "core", "aux";
263 interrupts = <10>; !! 235 interrupts = <10>;
264 interrupt-controller; !! 236 interrupt-controller;
265 }; 237 };
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