ThinkPad input device IDs

["Shem Multinymous" <multinymous@gmail.com>]

Hi Dmitry and Henrique,

We seem to have a bit of a mess in regard to input device
identification on ThinkPad-specific devices.

thinkpad-acpi does essentially the following (Henrique's commit
7f5d1cd62 from July 2007, after macro expansion):

        tpacpi_inputdev->name = "ThinkPad Extra Buttons";
        tpacpi_inputdev->phys = "thinkpad_acpi/input0";
        tpacpi_inputdev->id.bustype = BUS_HOST;
        tpacpi_inputdev->id.vendor = PCI_VENDOR_ID_IBM or PCI_VENDOR_ID_LENOVO;
        tpacpi_inputdev->id.product = 0x5054 /* "TP" */;
        tpacpi_inputdev->id.version = 0x4101;

But mainline hdaps uses a different convention (Dmitry's commit
d2fc60d692 from May 2008):

        idev->name = "hdaps";
        idev->phys = "isa1600/input0";
        idev->id.bustype = BUS_ISA;

What's the rationale for the different bus and phys convention?
Also, where does the "isa1600" come from, and why BUS_ISA? As far as I
can tell, the input device polls the ThinkPad embedded controller via
the LPC bus interface of the chipset, so no ISA-like bus is involved.

More concretely:
The out-of-tree tp_smapi version of hdaps followed the thinkpad-acpi
convention so it now conflicts with mainline hdaps. Which should I
follow?

  Shem