I've found two sites with Linux driver packages for Canon MG2120 series printers.
Scroll down to
Download Canon PIXMA MG2120 All-In-One Printer Driver for Linux (Ubuntu, Linux Mint, Debian, Fedora, openSUSE, and other distributions) to find a download link for the .deb package. If that package doesn't work for you, try scrolling down to the link for the source package and compile it for your computer.
Also, This site
has a source package, with instructions, for MG2120 series printers. Scroll down to 1 Answer for the download link and instructions.