Advanced Configuration and Power Interface Specification

Advanced Configuration and Power Interface Specification
• AccessType must be set to ByteAcc.
• LockRule indicates if access to this operation region requires acquisition of the Global Lock
for synchronization. Note that, on HW-reduced ACPI platforms, this field must be set to
NoLock.
• UpdateRule is not applicable to GeneralPurposeIO operation regions since Preserve is
always required. This field is ignored for all GeneralPurposeIO field definitions.
The following ASL code shows the use of the OperationRegion, Field, and Offset terms as they
apply to GeneralPurposeIO space.
Device(DEVA) //An Arbitrary Device Scope
{
...//Other required stuff for this device
Name (GMOD, ResourceTemplate () //An existing GPIO Connection (to be used later)
{
//2 Outputs that define the Power mode of the device
GpioIo (Exclusive, PullDown, , , , "\\_SB.GPI2") {10, 12}
})
} //End DEVA
Device (GPI2) //The OpRegion declaration, and the _REG method, must be in the controller’s
namespace scope
{
...//Other required stuff for the GPIO controller
OperationRegion(GPO2, GeneralPurposeIO, 0, 1) // Note: length of 1 means region is (or less
than) 1 byte (8 pins) long
Method(_REG,2) {} // Track availability of GeneralPurposeIO space
} //End GPI2
Device (DEVB) //Access some GPIO Pins from this device scope to change the device's power mode
{
...//Other required stuff for this device
Name(_DEP, Package() {"\\_SB.GPI2"}) //OpRegion Dependency hint for OSPM
Field(\_SB.GPI2.GPO2, ByteAcc, NoLock, Preserve)
{
Connection (GMOD), // Re-Use an existing connection (defined elsewhere)
MODE, 2, // Power Mode
Connection (GpioIo(Exclusive, PullUp, , , , "\\_SB.GPI2") {7}),
STAT, 1, // e.g. Status signal from the device
Connection (GpioIo (Exclusive, PullUp, , , , "\\_SB.GPI2") {9}),
RSET, 1 // e.g. Reset signal to the device
}
Method(_PS3)
{
If (1) // Make sure GeneralPurposeIO Region is available
{
Store(0x03, MODE) //Set both MODE bits. Power Mode 3
}
}
} //End DEVB
5.5.2.4.5 Declaring GenericSerialBus Operation Regions
For GenericSerialBus Operation Regions, the syntax for the OperationRegion term (from
Section 19.6.97, “OperationRegion (Declare Operation Region]”) is described below.
228 April, 2015 Version 6.0