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1 | # SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) |
2 | %YAML 1.2 | |
3 | --- | |
4 | $id: http://devicetree.org/schemas/i3c/i3c.yaml# | |
5 | $schema: http://devicetree.org/meta-schemas/core.yaml# | |
6 | ||
7 | title: I3C bus binding | |
8 | ||
9 | maintainers: | |
10 | - Alexandre Belloni <alexandre.belloni@bootlin.com> | |
11 | - Miquel Raynal <miquel.raynal@bootlin.com> | |
12 | ||
13 | description: | | |
14 | I3C busses can be described with a node for the primary I3C controller device | |
15 | and a set of child nodes for each I2C or I3C slave on the bus. Each of them | |
16 | may, during the life of the bus, request mastership. | |
17 | ||
18 | properties: | |
19 | $nodename: | |
20 | pattern: "^i3c-master@[0-9a-f]+$" | |
21 | ||
22 | "#address-cells": | |
23 | const: 3 | |
24 | description: | | |
25 | Each I2C device connected to the bus should be described in a subnode. | |
26 | ||
27 | All I3C devices are supposed to support DAA (Dynamic Address Assignment), | |
28 | and are thus discoverable. So, by default, I3C devices do not have to be | |
29 | described in the device tree. This being said, one might want to attach | |
30 | extra resources to these devices, and those resources may have to be | |
31 | described in the device tree, which in turn means we have to describe | |
32 | I3C devices. | |
33 | ||
34 | Another use case for describing an I3C device in the device tree is when | |
35 | this I3C device has a static I2C address and we want to assign it a | |
36 | specific I3C dynamic address before the DAA takes place (so that other | |
37 | devices on the bus can't take this dynamic address). | |
38 | ||
39 | "#size-cells": | |
40 | const: 0 | |
41 | ||
42 | i3c-scl-hz: | |
43 | description: | | |
44 | Frequency of the SCL signal used for I3C transfers. When undefined, the | |
45 | default value should be 12.5MHz. | |
46 | ||
47 | May not be supported by all controllers. | |
48 | ||
49 | i2c-scl-hz: | |
50 | description: | | |
51 | Frequency of the SCL signal used for I2C transfers. When undefined, the | |
52 | default should be to look at LVR (Legacy Virtual Register) values of | |
53 | I2C devices described in the device tree to determine the maximum I2C | |
54 | frequency. | |
55 | ||
56 | May not be supported by all controllers. | |
57 | ||
58 | required: | |
59 | - "#address-cells" | |
60 | - "#size-cells" | |
61 | ||
62 | patternProperties: | |
63 | "@[0-9a-f]+$": | |
64 | type: object | |
65 | description: | | |
66 | I2C child, should be named: <device-type>@<i2c-address> | |
67 | ||
68 | All properties described in Documentation/devicetree/bindings/i2c/i2c.txt | |
69 | are valid here, except the reg property whose content is changed. | |
70 | ||
71 | properties: | |
72 | compatible: | |
73 | description: | |
74 | Compatible of the I2C device. | |
75 | ||
76 | reg: | |
77 | items: | |
78 | - items: | |
79 | - description: | | |
80 | I2C address. 10 bit addressing is not supported. Devices with | |
81 | 10-bit address can't be properly passed through DEFSLVS | |
82 | command. | |
83 | minimum: 0 | |
84 | maximum: 0x7f | |
85 | - const: 0 | |
86 | - description: | | |
87 | Shall encode the I3C LVR (Legacy Virtual Register): | |
88 | bit[31:8]: unused/ignored | |
89 | bit[7:5]: I2C device index. Possible values: | |
90 | * 0: I2C device has a 50 ns spike filter | |
91 | * 1: I2C device does not have a 50 ns spike filter but | |
92 | supports high frequency on SCL | |
93 | * 2: I2C device does not have a 50 ns spike filter and is | |
94 | not tolerant to high frequencies | |
95 | * 3-7: reserved | |
96 | bit[4]: tell whether the device operates in FM (Fast Mode) | |
97 | or FM+ mode: | |
98 | * 0: FM+ mode | |
99 | * 1: FM mode | |
100 | bit[3:0]: device type | |
101 | * 0-15: reserved | |
102 | ||
103 | required: | |
104 | - compatible | |
105 | - reg | |
106 | ||
107 | "@[0-9a-f]+,[0-9a-f]+$": | |
108 | type: object | |
109 | description: | | |
110 | I3C child, should be named: <device-type>@<static-i2c-address>,<i3c-pid> | |
111 | ||
112 | properties: | |
113 | reg: | |
114 | items: | |
115 | - items: | |
116 | - description: | | |
117 | Encodes the static I2C address. Should be 0 if the device does | |
118 | not have one (0 is not a valid I2C address). | |
119 | minimum: 0 | |
120 | maximum: 0x7f | |
121 | - description: | | |
122 | First half of the Provisional ID (following the PID | |
123 | definition provided by the I3C specification). | |
124 | ||
125 | Contains the manufacturer ID left-shifted by 1. | |
126 | - description: | | |
127 | Second half of the Provisional ID (following the PID | |
128 | definition provided by the I3C specification). | |
129 | ||
130 | Contains the ORing of the part ID left-shifted by 16, | |
131 | the instance ID left-shifted by 12 and extra information. | |
132 | ||
133 | assigned-address: | |
134 | $ref: /schemas/types.yaml#/definitions/uint32 | |
135 | minimum: 0x1 | |
136 | maximum: 0xff | |
137 | description: | | |
138 | Dynamic address to be assigned to this device. This property is only | |
139 | valid if the I3C device has a static address (first cell of the reg | |
140 | property != 0). | |
141 | ||
142 | required: | |
143 | - reg | |
144 | ||
145 | additionalProperties: true | |
146 | ||
147 | examples: | |
148 | - | | |
149 | i3c-master@d040000 { | |
150 | compatible = "cdns,i3c-master"; | |
151 | clocks = <&coreclock>, <&i3csysclock>; | |
152 | clock-names = "pclk", "sysclk"; | |
153 | interrupts = <3 0>; | |
154 | reg = <0x0d040000 0x1000>; | |
155 | #address-cells = <3>; | |
156 | #size-cells = <0>; | |
157 | i2c-scl-hz = <100000>; | |
158 | ||
159 | /* I2C device. */ | |
28ffe8bf RH |
160 | eeprom@57 { |
161 | compatible = "atmel,24c01"; | |
162 | reg = <0x57 0x0 0x10>; | |
163 | pagesize = <0x8>; | |
5e4cdca8 MR |
164 | }; |
165 | ||
166 | /* I3C device with a static I2C address. */ | |
167 | thermal_sensor: sensor@68,39200144004 { | |
168 | reg = <0x68 0x392 0x144004>; | |
169 | assigned-address = <0xa>; | |
170 | }; | |
171 | ||
172 | /* | |
173 | * I3C device without a static I2C address but requiring | |
174 | * resources described in the DT. | |
175 | */ | |
176 | sensor@0,39200154004 { | |
177 | reg = <0x0 0x392 0x154004>; | |
178 | clocks = <&clock_provider 0>; | |
179 | }; | |
180 | }; |