World's most simple Windows driver

I have a slightly odd problem involving a MoGo mouse failing to charge when put in the cartridge slot of my Windows XP laptop. Long story, but one suggestion to fix it is to write a bespoke driver which only says "I'm functioning OK: don't turn the power off".

I'm figuring that this should be next to trivial, but my only experience of drivers is to download and install them through provided MSIs. I realised that I don't know:

What language they're written in.
What conventions they must follow.
How they are associated with their respective hardware.
Where they are located.
Or indeed, anything at all...

I also haven't found anything staggeringly helpful on the web - probably because they are aimed at a far higher level than I'm at.

Any insights would be welcome.

Solution

Microsoft provides a "Hello World" driver example in their documentation. This is an example of "World's most simple Windows driver". Unfortunately, it's 13 pages long and thus not a good fit for a StackOverflow answer.

The language they are written in is C++.

To get started, be sure you have Microsoft Visual Studio, the Windows SDK, and the Windows Driver Kit (WDK) installed.

Their example contains one file called Driver.c that looks like this:

#include <ntddk.h>
#include <wdf.h>
DRIVER_INITIALIZE DriverEntry;
EVT_WDF_DRIVER_DEVICE_ADD KmdfHelloWorldEvtDeviceAdd;

NTSTATUS 
DriverEntry(
    _In_ PDRIVER_OBJECT     DriverObject, 
    _In_ PUNICODE_STRING    RegistryPath
)
{
    // NTSTATUS variable to record success or failure
    NTSTATUS status = STATUS_SUCCESS;

    // Allocate the driver configuration object
    WDF_DRIVER_CONFIG config;

    // Print "Hello World" for DriverEntry
    KdPrintEx(( DPFLTR_IHVDRIVER_ID, DPFLTR_INFO_LEVEL, "KmdfHelloWorld: DriverEntry\n" ));

    // Initialize the driver configuration object to register the
    // entry point for the EvtDeviceAdd callback, KmdfHelloWorldEvtDeviceAdd
    WDF_DRIVER_CONFIG_INIT(&config, 
                           KmdfHelloWorldEvtDeviceAdd
                           );

    // Finally, create the driver object
    status = WdfDriverCreate(DriverObject, 
                             RegistryPath, 
                             WDF_NO_OBJECT_ATTRIBUTES, 
                             &config, 
                             WDF_NO_HANDLE
                             );
    return status;
}

NTSTATUS 
KmdfHelloWorldEvtDeviceAdd(
    _In_    WDFDRIVER       Driver, 
    _Inout_ PWDFDEVICE_INIT DeviceInit
)
{
    // We're not using the driver object,
    // so we need to mark it as unreferenced
    UNREFERENCED_PARAMETER(Driver);

    NTSTATUS status;

    // Allocate the device object
    WDFDEVICE hDevice;    

    // Print "Hello World"
    KdPrintEx(( DPFLTR_IHVDRIVER_ID, DPFLTR_INFO_LEVEL, "KmdfHelloWorld: KmdfHelloWorldEvtDeviceAdd\n" ));

    // Create the device object
    status = WdfDeviceCreate(&DeviceInit, 
                             WDF_NO_OBJECT_ATTRIBUTES,
                             &hDevice
                             );
    return status;
}

Full details found here: https://learn.microsoft.com/en-us/windows-hardware/drivers/gettingstarted/writing-a-very-small-kmdf--driver