Touchpad with 2 buttons instead of clickpad?

[C_Scott_Ananian]

Mechanical side looks straightforward:

Thinkpad keyboard mod (super early stages)!

I did a test fit of this as well: [PXL_20240616_185121717.MP] The size seems quite comparable. I don’t know how many folks would be interested in such a thing, and I’d probably have to poke @nrp for a little more detail on the software side of the touchpad interface (what’s published now is just “it’s I2C” with no protocol info) but it seems it could work mechanically. Underside comparison: [PXL_20240616_185413234.MP]

I’m using a T470S clickpad module, and the schematic on the T470S side of this looks like this:

And very similar on the T480S:

It’s I2C at least – /three/ I2C buses actually: TP4CLK/DATA (trackpoint bus), SMB_CLK/DATA_3B, and IPDCLK/DATA. No obvious interrupt, but a bunch of disable signals: /LID_CLOSE, PAD_DISABLE, and NFC_ACTIVE.

I confirmed that my module has a 12 pin connector, and pin 1 is actually marked on the module. The FPC connector is Kyocera 04-6811-612-000-846 https://ele.kyocera.com/en/product/connector/fpcffc_connectors/6811/046811612000846/ which is 12 pin, 0.5mm pitch, at least on the motherboard side. Looks like the module connector is the same.

I guess the next step is to make a little breakout board, wire up all three I2C buses, and enumerate them all and see what shows up.

EDIT 2024-07-08: The T470s schematic matches the pin 1 marked on the module; the T480s schematic has the pins/FPC flipped. Scanning the I2C bus turns up a device 0x2C on the SMB_CLK/SMB_DATA bus, nothing (yet?) on the other two.