GPIO_CLIENT_CLEAR_ACTIVE_INTERRUPTS callback function (gpioclx.h)

Article
10/21/2021

The CLIENT_ClearActiveInterrupts event callback function clears active interrupts on a set of general-purpose I/O (GPIO) pins that are configured as interrupt inputs.

Syntax

GPIO_CLIENT_CLEAR_ACTIVE_INTERRUPTS GpioClientClearActiveInterrupts;

NTSTATUS GpioClientClearActiveInterrupts(
  [in]      PVOID Context,
  [in, out] PGPIO_CLEAR_ACTIVE_INTERRUPTS_PARAMETERS ClearParameters
)
{...}

Parameters

[in] Context

A pointer to the GPIO controller driver's device context.

[in, out] ClearParameters

A pointer to a GPIO_CLEAR_ACTIVE_INTERRUPTS_PARAMETERS structure that, on entry, describes the GPIO interrupt pins to clear, and, on exit, contains the status of the clear operation.

Return value

The CLIENT_ClearActiveInterrupts function returns STATUS_SUCCESS if the call is successful. Otherwise, it returns an appropriate error code.

Remarks

This callback function is implemented by the general-purpose I/O (GPIO) controller driver. The GPIO framework extension (GpioClx) calls this function to clear active interrupts on GPIO pins that are configured as interrupt request inputs.

This callback function is optional. If the GPIO controller hardware automatically clears active interrupt status bits when they are read, the driver should not register a CLIENT_ClearActiveInterrupts callback function. For more information, see Optional and Required GPIO Callback Functions.

To register your driver's CLIENT_ClearActiveInterrupts callback function, call the GPIO_CLX_RegisterClient method. This method accepts, as an input parameter, a pointer to a GPIO_CLIENT_REGISTRATION_PACKET structure that contains a CLIENT_ClearActiveInterrupts function pointer.

GpioClx calls the CLIENT_ClearActiveInterrupts callback function at either PASSIVE_LEVEL or DIRQL, depending on the device information that the CLIENT_QueryControllerBasicInformation callback function supplies to GpioClx. The CLIENT_QueryControllerBasicInformation function provides device information in the form of a CLIENT_CONTROLLER_BASIC_INFORMATION structure. If the MemoryMappedController flag bit is set in the Flags member of this structure, GpioClx calls the CLIENT_ClearActiveInterrupts function at DIRQL, which is the IRQL at which the ISR in GpioClx runs. Otherwise, this function is called at PASSIVE_LEVEL. For more information about this flag bit, see Interrupt-Related Callbacks.

Examples

To define a CLIENT_ClearActiveInterrupts callback function, you must first provide a function declaration that identifies the type of callback function you're defining. Windows provides a set of callback function types for drivers. Declaring a function using the callback function types helps Code Analysis for Drivers, Static Driver Verifier (SDV), and other verification tools find errors, and it's a requirement for writing drivers for the Windows operating system.

For example, to define a CLIENT_ClearActiveInterrupts callback function that is named MyEvtGpioClearActiveInterrupts, use the GPIO_CLIENT_CLEAR_ACTIVE_INTERRUPTS function type, as shown in this code example:

GPIO_CLIENT_CLEAR_ACTIVE_INTERRUPTS MyEvtGpioClearActiveInterrupts;

Then, implement your callback function as follows:

_Use_decl_annotations_
NTSTATUS
  MyEvtGpioClearActiveInterrupts(
    PVOID Context,
    PGPIO_CLEAR_ACTIVE_INTERRUPTS_PARAMETERS ClearParameters
    )
{ ... }

The GPIO_CLIENT_CLEAR_ACTIVE_INTERRUPTS function type is defined in the Gpioclx.h header file. To more accurately identify errors when you run the code analysis tools, be sure to add the Use_decl_annotations annotation to your function definition. The Use_decl_annotations annotation ensures that the annotations that are applied to the GPIO_CLIENT_CLEAR_ACTIVE_INTERRUPTS function type in the header file are used. For more information about the requirements for function declarations, see Declaring Functions by Using Function Role Types for KMDF Drivers. For more information about Use_decl_annotations, see Annotating Function Behavior.

Requirements

Requirement	Value
Minimum supported client	Supported starting with Windows 8.
Target Platform	Desktop
Header	gpioclx.h
IRQL	See Remarks.