1 # SPDX-License-Identifier: GPL-2.0
2 %YAML 1.2
3 ---
4 $id: http://devicetree.org/schemas/mux/mux-controller.yaml#
5 $schema: http://devicetree.org/meta-schemas/core.yaml#
6
7 title: Common multiplexer controller provider
8
9 maintainers:
10 - Peter Rosin <peda@axentia.se>
11
12 description: |
13 A multiplexer (or mux) controller will have one, or several, consumer devices
14 that uses the mux controller. Thus, a mux controller can possibly control
15 several parallel multiplexers. Presumably there will be at least one
16 multiplexer needed by each consumer, but a single mux controller can of course
17 control several multiplexers for a single consumer.
18
19 A mux controller provides a number of states to its consumers, and the state
20 space is a simple zero-based enumeration. I.e. 0-1 for a 2-way multiplexer,
21 0-7 for an 8-way multiplexer, etc.
22
23
24 Mux controller nodes
25 --------------------
26
27 Mux controller nodes must specify the number of cells used for the
28 specifier using the '#mux-control-cells' or '#mux-state-cells' property.
29 The value of '#mux-state-cells' will always be one greater than the value
30 of '#mux-control-cells'.
31
32 Optionally, mux controller nodes can also specify the state the mux should
33 have when it is idle. The idle-state property is used for this. If the
34 idle-state is not present, the mux controller is typically left as is when
35 it is idle. For multiplexer chips that expose several mux controllers, the
36 idle-state property is an array with one idle state for each mux controller.
37
38 The special value (-1) may be used to indicate that the mux should be left
39 as is when it is idle. This is the default, but can still be useful for
40 mux controller chips with more than one mux controller, particularly when
41 there is a need to "step past" a mux controller and set some other idle
42 state for a mux controller with a higher index.
43
44 Some mux controllers have the ability to disconnect the input/output of the
45 multiplexer. Using this disconnected high-impedance state as the idle state
46 is indicated with idle state (-2).
47
48 These constants are available in
49
50 #include <dt-bindings/mux/mux.h>
51
52 as MUX_IDLE_AS_IS (-1) and MUX_IDLE_DISCONNECT (-2).
53
54 An example mux controller node look like this (the adg972a chip is a triple
55 4-way multiplexer):
56
57 mux: mux-controller@50 {
58 compatible = "adi,adg792a";
59 reg = <0x50>;
60 #mux-control-cells = <1>;
61
62 idle-state = <MUX_IDLE_DISCONNECT MUX_IDLE_AS_IS 2>;
63 };
64
65 select:
66 anyOf:
67 - properties:
68 $nodename:
69 pattern: '^mux-controller'
70 - required:
71 - '#mux-control-cells'
72 - required:
73 - '#mux-state-cells'
74
75 properties:
76 $nodename:
77 pattern: '^mux-controller(@.*|-([0-9]|[1-9][0-9]+))?$'
78
79 '#mux-control-cells':
80 enum: [ 0, 1 ]
81
82 '#mux-state-cells':
83 enum: [ 1, 2 ]
84
85 idle-state:
86 $ref: /schemas/types.yaml#/definitions/int32
87 minimum: -2
88
89 idle-states:
90 description: |
91 Mux controller nodes can specify the state the mux should have when it is
92 idle. If the idle-state is not present, the mux controller is typically
93 left as is when it is idle. For multiplexer chips that expose several mux
94 controllers, the idle-state property is an array with one idle state for
95 each mux controller.
96
97 The special value (-1) may be used to indicate that the mux should be left
98 as is when it is idle. This is the default, but can still be useful for
99 mux controller chips with more than one mux controller, particularly when
100 there is a need to "step past" a mux controller and set some other idle
101 state for a mux controller with a higher index.
102
103 Some mux controllers have the ability to disconnect the input/output of the
104 multiplexer. Using this disconnected high-impedance state as the idle state
105 is indicated with idle state (-2).
106 $ref: /schemas/types.yaml#/definitions/int32-array
107 items:
108 minimum: -2
109
110 additionalProperties: true
111
112 examples:
113 - |
114 #include <dt-bindings/gpio/gpio.h>
115
116 /* One consumer of a 2-way mux controller (one GPIO-line) */
117 mux: mux-controller {
118 compatible = "gpio-mux";
119 #mux-control-cells = <0>;
120
121 mux-gpios = <&pioA 0 GPIO_ACTIVE_HIGH>;
122 };
123
124 adc-mux {
125 compatible = "io-channel-mux";
126 io-channels = <&adc 0>;
127 io-channel-names = "parent";
128
129 mux-controls = <&mux>;
130 mux-control-names = "adc";
131
132 channels = "sync", "in";
133 };
134
135 - |
136 #include <dt-bindings/gpio/gpio.h>
137
138 /*
139 * Two consumers (one for an ADC line and one for an i2c bus) of
140 * parallel 4-way multiplexers controlled by the same two GPIO-lines.
141 */
142 mux2: mux-controller {
143 compatible = "gpio-mux";
144 #mux-control-cells = <0>;
145
146 mux-gpios = <&pioA 0 GPIO_ACTIVE_HIGH>,
147 <&pioA 1 GPIO_ACTIVE_HIGH>;
148 };
149
150 adc-mux {
151 compatible = "io-channel-mux";
152 io-channels = <&adc 0>;
153 io-channel-names = "parent";
154
155 mux-controls = <&mux2>;
156
157 channels = "sync-1", "in", "out", "sync-2";
158 };
159
160 i2c-mux {
161 compatible = "i2c-mux";
162 i2c-parent = <&i2c1>;
163
164 mux-controls = <&mux2>;
165
166 #address-cells = <1>;
167 #size-cells = <0>;
168
169 i2c@0 {
170 reg = <0>;
171 #address-cells = <1>;
172 #size-cells = <0>;
173
174 ssd1307: oled@3c {
175 reg = <0x3c>;
176 };
177 };
178
179 i2c@3 {
180 reg = <3>;
181 #address-cells = <1>;
182 #size-cells = <0>;
183
184 pca9555: pca9555@20 {
185 reg = <0x20>;
186 };
187 };
188 };
189
190 - |
191 #include <dt-bindings/gpio/gpio.h>
192
193 mux1: mux-controller {
194 compatible = "gpio-mux";
195 #mux-state-cells = <1>;
196 mux-gpios = <&exp_som 2 GPIO_ACTIVE_HIGH>;
197 };
198
199 transceiver4: can-phy4 {
200 compatible = "ti,tcan1042";
201 #phy-cells = <0>;
202 max-bitrate = <5000000>;
203 standby-gpios = <&exp_som 7 GPIO_ACTIVE_HIGH>;
204 mux-states = <&mux1 1>;
205 };
206 ...
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.