Advanced Configuration and Power Interface Specification

Advanced Configuration and Power Interface Specification
5.6.5 GPIO-signaled ACPI Events
On Hardware-reduced ACPI platforms, ACPI events are signaled when a GPIO Interrupt is received
by OSPM, and that GPIO Interrupt Connection is listed in a GPIO controller device’s _AEI object.
OSPM claims all such GPIO interrupts, and maps them to the appropriate event method required by
the ACPI event model.
5.6.5.1 Declaring GPIO Controller Devices
A GPIO controller is modeled as a device in the namespace, with _HID or _ADR and _CRS objects,
at a minimum. Optionally, the GPIO controller device scope may include GeneralPurposeIO
OpRegion declarations ( Section 5.5.2.4.4) and GPIO interrupt-to-ACPI Event mappings
(Section 5.6.5.2). Note that for GPIO-signaled ACPI events, the corresponding event method (e.g.
_Exx, _Lxx, or _EVT) must also appear in the target GPIO controller’s scope. For GPIO event
numbers larger than 255 (0xFF), the _EVT method is used.
Each pin on a GPIO Controller has a configuration (e.g. level-sensitive interrupt, de-bounced input,
high-drive output, etc.), which is described to OSPM in the GPIO Interrupt or GPIO IO Connection
resources claimed by peripheral devices or used in operation region accesses.
5.6.5.2 _AEI Object
The _AEI object designates those GPIO interrupts that shall be handled by OSPM as ACPI events
(See Section 5.6.5). This object appears within the scope of the GPIO controller device whose pins
are to be used as GPIO-signaled events.
Arguments:
None
Return Value:
A resource template Buffer containing only GPIO Interrupt Connection descriptors.
Example:
Device (\_SB.GPI2)
{
Name(_HID, “XYZ0003”)
Name(_UID, 2)
//Third instance of this controller on the platform
Name(_CRS, ResourceTemplate ()
{
//Register Interface
MEMORY32FIXED(ReadWrite, 0x30000000, 0x200, )
//Interrupt line (GSIV 21)
Interrupt(ResourceConsumer, Level, ActiveHigh, Exclusive) {21}
})
Name(_AEI, ResourceTemplate ()
{
//Thermal Zone Event
GpioInt(Edge, ActiveHigh, Exclusive, PullDown, , " \\_SB.GPI2") {14}
//Power Button
GpioInt(Edge, ActiveLow, ExclusiveAndWake, PullUp, , " \\_SB.GPI2") {36}
})
}
248 April, 2015 Version 6.0