# libfprint GXFP5130 integration skeleton

This driver connects libfprint's `FpImageDevice` state machine to the
hardware-tested `gxfp_session` API. Blocking sensor operations run in a GLib
worker thread; all libfprint callbacks run in the main context.

Current discovery is intentionally explicit because the sensor is an ACPI
platform/character device, while upstream libfprint has no generic ACPI char
device discovery type. Build the driver as an optional virtual-type driver and
start libfprint/fprintd with:

```sh
FP_GXFP5130=/dev/gxfp
```

The integration must add `gxfp5130` to `drivers_info` and
`libfprint_drivers_sources` in upstream Meson, include this file, add the GXFP
headers, and link the PIC-built `libgxfp.a` plus mbedTLS libraries.

The first image path uses the verified 64x80 sample order and the deterministic
`gxfp_image12_to_u8()` conversion. No transpose, flip, inversion, percentile
clipping, or unverified `0x21` command is applied.

Before upstreaming, replace the environment-backed discovery with a dedicated
udev/ACPI character-device discovery mechanism and install permissions for
`/dev/gxfp`.