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