This page tracks all the TPM integration projects and their status
OpenSSL TPM2 Engine
The source code repository is here and the mailing list is here. There is also a build service repository for various distributions here.
Upstream has a tpm-work branch here. All proposed additions to this branch are send to the gnupg-devel mailing list. The current patch set against the latest released version (which is not the same as the tpm-work branch) can be obtained from the build service here. The build service has a separate debian build for the same patches here (it has to be a different repository because the package has a different name)