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 Device
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 The items should have a fixed order, so pattern matching names are
84 discouraged. 85 discouraged.
85 86
86 clock-names: 87 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: 88 items:
91 - const: bus 89 - const: bus
92 90
93 interrupts: 91 interrupts:
94 # Either 1 or 2 interrupts can be present 92 # Either 1 or 2 interrupts can be present
95 minItems: 1 93 minItems: 1
96 items: 94 items:
97 - description: tx or combined interrupt 95 - description: tx or combined interrupt
98 - description: rx interrupt 96 - description: rx interrupt
99 description: 97 description:
100 A variable number of interrupts warrants 98 A variable number of interrupts warrants a description of what conditions
101 affect the number of interrupts. Otherwi 99 affect the number of interrupts. Otherwise, descriptions on standard
102 properties are not necessary. 100 properties are not necessary.
103 The items should have a fixed order, so 101 The items should have a fixed order, so pattern matching names are
104 discouraged. 102 discouraged.
105 103
106 interrupt-names: 104 interrupt-names:
107 # minItems must be specified here because 105 # minItems must be specified here because the default would be 2
108 minItems: 1 106 minItems: 1
109 items: 107 items:
110 - const: tx irq 108 - const: tx irq
111 - const: rx irq 109 - const: rx irq
112 110
113 # Property names starting with '#' must be q 111 # Property names starting with '#' must be quoted
114 '#interrupt-cells': 112 '#interrupt-cells':
115 # A simple case where the value must alway 113 # A simple case where the value must always be '2'.
116 # The core schema handles that this must b 114 # The core schema handles that this must be a single integer.
117 const: 2 115 const: 2
118 116
119 interrupt-controller: true 117 interrupt-controller: true
120 # The core checks this is a boolean, so ju 118 # The core checks this is a boolean, so just have to list it here to be
121 # valid for this binding. 119 # valid for this binding.
122 120
123 clock-frequency: 121 clock-frequency:
124 # The type is set in the core schema. Per- 122 # The type is set in the core schema. Per-device schema only need to set
125 # constraints on the possible values. 123 # constraints on the possible values.
126 minimum: 100 124 minimum: 100
127 maximum: 400000 125 maximum: 400000
128 # The value that should be used if the pro 126 # The value that should be used if the property is not present
129 default: 200 127 default: 200
130 128
131 foo-gpios: 129 foo-gpios:
132 maxItems: 1 130 maxItems: 1
133 description: A connection of the 'foo' gpi 131 description: A connection of the 'foo' gpio line.
134 132
135 # *-supply is always a single phandle, so no 133 # *-supply is always a single phandle, so nothing more to define.
136 foo-supply: true 134 foo-supply: true
137 135
138 # Vendor-specific properties 136 # Vendor-specific properties
139 # 137 #
140 # Vendor-specific properties have slightly d 138 # Vendor-specific properties have slightly different schema requirements than
141 # common properties. They must have at least 139 # common properties. They must have at least a type definition and
142 # 'description'. 140 # 'description'.
143 vendor,int-property: 141 vendor,int-property:
144 description: Vendor-specific properties mu 142 description: Vendor-specific properties must have a description
145 $ref: /schemas/types.yaml#/definitions/uin 143 $ref: /schemas/types.yaml#/definitions/uint32
146 enum: [2, 4, 6, 8, 10] 144 enum: [2, 4, 6, 8, 10]
147 145
148 vendor,bool-property: 146 vendor,bool-property:
149 description: Vendor-specific properties mu 147 description: Vendor-specific properties must have a description. Boolean
150 properties are one case where the json-s 148 properties are one case where the json-schema 'type' keyword can be used
151 directly. 149 directly.
152 type: boolean 150 type: boolean
153 151
154 vendor,string-array-property: 152 vendor,string-array-property:
155 description: Vendor-specific properties sh 153 description: Vendor-specific properties should reference a type in the
156 core schema. 154 core schema.
157 $ref: /schemas/types.yaml#/definitions/str 155 $ref: /schemas/types.yaml#/definitions/string-array
158 items: 156 items:
159 - enum: [foo, bar] 157 - enum: [foo, bar]
160 - enum: [baz, boo] 158 - enum: [baz, boo]
161 159
162 vendor,property-in-standard-units-microvolt: 160 vendor,property-in-standard-units-microvolt:
163 description: Vendor-specific properties ha 161 description: Vendor-specific properties having a standard unit suffix
164 don't need a type. 162 don't need a type.
165 enum: [ 100, 200, 300 ] 163 enum: [ 100, 200, 300 ]
166 164
167 vendor,int-array-variable-length-and-constra 165 vendor,int-array-variable-length-and-constrained-values:
168 description: Array might define what type 166 description: Array might define what type of elements might be used (e.g.
169 their range). 167 their range).
170 $ref: /schemas/types.yaml#/definitions/uin 168 $ref: /schemas/types.yaml#/definitions/uint32-array
171 minItems: 2 169 minItems: 2
172 maxItems: 3 170 maxItems: 3
173 items: 171 items:
174 minimum: 0 172 minimum: 0
175 maximum: 8 173 maximum: 8
176 174
177 child-node: 175 child-node:
178 description: Child nodes are just another 176 description: Child nodes are just another property from a json-schema
179 perspective. 177 perspective.
180 type: object # DT nodes are json objects 178 type: object # DT nodes are json objects
181 # Child nodes also need additionalProperti <<
182 additionalProperties: false <<
183 properties: 179 properties:
184 vendor,a-child-node-property: 180 vendor,a-child-node-property:
185 description: Child node properties hav 181 description: Child node properties have all the same schema
186 requirements. 182 requirements.
187 type: boolean 183 type: boolean
188 184
189 required: 185 required:
190 - vendor,a-child-node-property 186 - vendor,a-child-node-property
191 187
192 # Describe the relationship between different 188 # Describe the relationship between different properties
193 dependencies: 189 dependencies:
194 # 'vendor,bool-property' is only allowed whe 190 # 'vendor,bool-property' is only allowed when 'vendor,string-array-property'
195 # is present 191 # is present
196 vendor,bool-property: [ 'vendor,string-array 192 vendor,bool-property: [ 'vendor,string-array-property' ]
197 # Expressing 2 properties in both orders mea 193 # Expressing 2 properties in both orders means all of the set of properties
198 # must be present or none of them. 194 # must be present or none of them.
199 vendor,string-array-property: [ 'vendor,bool 195 vendor,string-array-property: [ 'vendor,bool-property' ]
200 196
201 required: 197 required:
202 - compatible 198 - compatible
203 - reg 199 - reg
204 - interrupts 200 - interrupts
205 - interrupt-controller 201 - interrupt-controller
206 202
207 # if/then schema can be used to handle conditi 203 # if/then schema can be used to handle conditions on a property affecting
208 # another property. A typical case is a specif 204 # another property. A typical case is a specific 'compatible' value changes the
209 # constraints on other properties. 205 # constraints on other properties.
210 # 206 #
211 # For multiple 'if' schema, group them under a 207 # For multiple 'if' schema, group them under an 'allOf'.
212 # 208 #
213 # If the conditionals become too unweldy, then 209 # If the conditionals become too unweldy, then it may be better to just split
214 # the binding into separate schema documents. 210 # the binding into separate schema documents.
215 allOf: 211 allOf:
216 - if: 212 - if:
217 properties: 213 properties:
218 compatible: 214 compatible:
219 contains: 215 contains:
220 const: vendor,soc2-ip 216 const: vendor,soc2-ip
221 then: 217 then:
222 required: 218 required:
223 - foo-supply 219 - foo-supply
224 else: 220 else:
225 # If otherwise the property is not allow 221 # If otherwise the property is not allowed:
226 properties: 222 properties:
227 foo-supply: false 223 foo-supply: false
228 # Altering schema depending on presence of p 224 # Altering schema depending on presence of properties is usually done by
229 # dependencies (see above), however some adj 225 # dependencies (see above), however some adjustments might require if:
230 - if: 226 - if:
231 required: 227 required:
232 - vendor,bool-property 228 - vendor,bool-property
233 then: 229 then:
234 properties: 230 properties:
235 vendor,int-property: 231 vendor,int-property:
236 enum: [2, 4, 6] 232 enum: [2, 4, 6]
237 233
238 # Ideally, the schema should have this line ot 234 # Ideally, the schema should have this line otherwise any other properties
239 # present are allowed. There's a few common pr 235 # present are allowed. There's a few common properties such as 'status' and
240 # 'pinctrl-*' which are added automatically by 236 # 'pinctrl-*' which are added automatically by the tooling.
241 # 237 #
242 # This can't be used in cases where another sc 238 # This can't be used in cases where another schema is referenced
243 # (i.e. allOf: [{$ref: ...}]). 239 # (i.e. allOf: [{$ref: ...}]).
244 # If and only if another schema is referenced 240 # If and only if another schema is referenced and arbitrary children nodes can
245 # appear, "unevaluatedProperties: false" could 241 # appear, "unevaluatedProperties: false" could be used. A typical example is
246 # an I2C controller where no name pattern matc 242 # an I2C controller where no name pattern matching for children can be added.
247 additionalProperties: false 243 additionalProperties: false
248 244
249 examples: 245 examples:
250 # Examples are now compiled with dtc and val 246 # Examples are now compiled with dtc and validated against the schemas
251 # 247 #
252 # Examples have a default #address-cells and 248 # Examples have a default #address-cells and #size-cells value of 1. This can
253 # be overridden or an appropriate parent bus 249 # be overridden or an appropriate parent bus node should be shown (such as on
254 # i2c buses). 250 # i2c buses).
255 # 251 #
256 # Any includes used have to be explicitly in 252 # Any includes used have to be explicitly included. Use 4-space indentation.
257 - | 253 - |
258 node@1000 { 254 node@1000 {
259 compatible = "vendor,soc4-ip", "vendor 255 compatible = "vendor,soc4-ip", "vendor,soc1-ip";
260 reg = <0x1000 0x80>, 256 reg = <0x1000 0x80>,
261 <0x3000 0x80>; 257 <0x3000 0x80>;
262 reg-names = "core", "aux"; 258 reg-names = "core", "aux";
263 interrupts = <10>; 259 interrupts = <10>;
264 interrupt-controller; 260 interrupt-controller;
265 }; 261 };
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.