For openSUSE Factory PPC run the following as root:
zypper addrepo https://download.opensuse.org/repositories/hardware/openSUSE_Factory_PPC/hardware.repo
zypper refresh
zypper install ppc64-diag
For 15.6 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/hardware/15.6/hardware.repo
zypper refresh
zypper install ppc64-diag
For 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/hardware/15.5/hardware.repo
zypper refresh
zypper install ppc64-diag