Advanced Configuration and Power Interface Specification

Device Configuration
Offset Field Name, ASL Field Name Definition
Byte 6 Access Size, _ASZ Specifies access size.
0 - Undefined (legacy reasons)
1 - Byte access
2 - Word access
3 - Dword access
4 - QWord access
Byte 7 Register Address, _ADR bits[7:0] Register Address
Byte 8 Register Address, _ADR bits[15:8]
Byte 9 Register Address, _ADR bits[23:16]
Byte 10 Register Address, _ADR bits[31:24]
Byte 11 Register Address, _ADR bits[39:32]
Byte 12 Register Address, _ADR bits[47:40]
Byte 13 Register Address, _ADR bits[55:48]
Byte 14 Register Address, _ADR bits[63:56]
See Register (page 880) for a description of the ASL macro that creates a Generic Register resource
descriptor.
6.4.3.8 Connection Descriptors
General-purpose I/O (GPIO) and Simple Peripheral Bus (SPB) controllers are hardware resources
provided in silicon solutions to enable flexible configuration of a broad range of system designs.
These controllers can provide input, output, interrupt and serial communication connections to
arbitrary devices in a system. The function to which one of these connections is put depends on the
specific device involved and the needs of the platform design. In order to support mobile platform
architectures, ACPI abstracts these connections as resources.
6.4.3.8.1 GPIO Connection Descriptor
Type 1, Large Item Name 0xC
The GPIO Connection Descriptor describes connections between GPIO controllers and peripheral
devices. Two types of GPIO connections can be described: IO connections and Interrupt
connections, distinguished by the GPIO Connection Type value in the descriptor. GPIO controllers
and the devices that connect to them may be located anywhere in the namespace, but the connection
must be described in the peripheral device's resource objects (PRS, _CRS, etc.).
Table 6-218 GPIO Connection Descriptor Definition
Offset Field Name Definition
Byte 0
GPIO
Connection
Descriptor
Value = 0x8C, (10001100B) – Type = 1, Large item name =
0x0C
Byte 1
Byte 2
Length,
bits[7:0]
Length,
bits[15:8]
Variable length, minimum value = 0x16 + L (22 + length of the
Resource Source Name string)
Variable length, minimum value = 0x00
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