1 .. SPDX-License-Identifier: GPL-2.0
2
3 ==============
4 ACPI I2C Muxes
5 ==============
6
7 Describing an I2C device hierarchy that includes I2C muxes requires an ACPI
8 Device () scope per mux channel.
9
10 Consider this topology::
11
12 +------+ +------+
13 | SMB1 |-->| MUX0 |--CH00--> i2c client A (0x50)
14 | | | 0x70 |--CH01--> i2c client B (0x50)
15 +------+ +------+
16
17 which corresponds to the following ASL::
18
19 Device (SMB1)
20 {
21 Name (_HID, ...)
22 Device (MUX0)
23 {
24 Name (_HID, ...)
25 Name (_CRS, ResourceTemplate () {
26 I2cSerialBus (0x70, ControllerInitiated, I2C_SPEED,
27 AddressingMode7Bit, "^SMB1", 0x00,
28 ResourceConsumer,,)
29 }
30
31 Device (CH00)
32 {
33 Name (_ADR, 0)
34
35 Device (CLIA)
36 {
37 Name (_HID, ...)
38 Name (_CRS, ResourceTemplate () {
39 I2cSerialBus (0x50, ControllerInitiated, I2C_SPEED,
40 AddressingMode7Bit, "^CH00", 0x00,
41 ResourceConsumer,,)
42 }
43 }
44 }
45
46 Device (CH01)
47 {
48 Name (_ADR, 1)
49
50 Device (CLIB)
51 {
52 Name (_HID, ...)
53 Name (_CRS, ResourceTemplate () {
54 I2cSerialBus (0x50, ControllerInitiated, I2C_SPEED,
55 AddressingMode7Bit, "^CH01", 0x00,
56 ResourceConsumer,,)
57 }
58 }
59 }
60 }
61 }
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