File: i2c-muxes.txt

package info (click to toggle)
linux 4.19.235-1
  • links: PTS, VCS
  • area: main
  • in suites: buster
  • size: 968,876 kB
  • sloc: ansic: 16,807,772; asm: 272,130; makefile: 38,425; sh: 33,854; perl: 27,702; python: 21,148; cpp: 5,068; yacc: 4,650; lex: 2,584; awk: 1,386; ruby: 25; sed: 5
file content (58 lines) | stat: -rw-r--r-- 1,505 bytes parent folder | download | duplicates (11)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
ACPI I2C Muxes
--------------

Describing an I2C device hierarchy that includes I2C muxes requires an ACPI
Device () scope per mux channel.

Consider this topology:

+------+   +------+
| SMB1 |-->| MUX0 |--CH00--> i2c client A (0x50)
|      |   | 0x70 |--CH01--> i2c client B (0x50)
+------+   +------+

which corresponds to the following ASL:

Device (SMB1)
{
    Name (_HID, ...)
    Device (MUX0)
    {
        Name (_HID, ...)
        Name (_CRS, ResourceTemplate () {
            I2cSerialBus (0x70, ControllerInitiated, I2C_SPEED,
                          AddressingMode7Bit, "^SMB1", 0x00,
                          ResourceConsumer,,)
        }

        Device (CH00)
        {
            Name (_ADR, 0)

            Device (CLIA)
            {
                Name (_HID, ...)
                Name (_CRS, ResourceTemplate () {
                    I2cSerialBus (0x50, ControllerInitiated, I2C_SPEED,
                                  AddressingMode7Bit, "^CH00", 0x00,
                                  ResourceConsumer,,)
                }
            }
        }

        Device (CH01)
        {
            Name (_ADR, 1)

            Device (CLIB)
            {
                Name (_HID, ...)
                Name (_CRS, ResourceTemplate () {
                    I2cSerialBus (0x50, ControllerInitiated, I2C_SPEED,
                                  AddressingMode7Bit, "^CH01", 0x00,
                                  ResourceConsumer,,)
                }
            }
        }
    }
}