I first wrote about ZPODD support on Linux last May in Better Power Savings With ZPODD On Linux. The Zero-Power Optical Disk Drive is a feature of the Serial ATA 3.1 specification that allows for idle SATA optical disk drives to zero out their energy use if it's not being utilized, thus better energy efficiency on Linux.
It's taken a while, but with the Linux 3.9 kernel the Zero-Power Optical Device Driver is finally being mainlined. The libata pull for Linux 3.9 also adds in a Serial ATA driver for the R-Car SoC and some other random changes. The pull request can be found on the Linux kernel mailing list.