lsusb will give some confusing output since it will identify the manufacturer and not necessarily the name that's on the label on the box (I believe it does a lookup of the device code declared by the USB device and a list of known companies/devices - hence the recognition when you plug something in). Anyway, that means you'll frequently get some unidentifiable Chinese company, and it's thus a process of elimination which device to choose:
1. Can you recognise anything else as any of your other USB devices? It's not them, then! Anything obvious like "HCI device", "Mouse", "Keyboard", etc.
2. Can you unplug any other USB devices? If an entry disappears, it's not that either - ultimately, it must be whatever is left.
My logic - and I haven't tried this, so I could well be talking wombats - would be this:
I think the entry to the wakeup file is probably the first number associated with the relevant USB device. Taking the output above...
Code:
Bus 002 Device 002: ID 05a4:9881 Ortek Technology, Inc.
Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
So Bus 2 (USB2) has two devices on it - the hub (how the computer sees it as a device, the USB 1.1 socket, effectively) and the IR receiver (the "Ortek" device) that's plugged into this. Either way, the computer would see the signal on that connection, so "002" is your answer - hence "USB2".
lsusb -v should tell you more about a specific device, although whether that "more" will be at all useful, I leave to your imagination...
Give it a try until someone can correct me, anyway :-)