There are two lint groups in Clippy. The clippy lint group will control all the lints that warn by default, and you can, for example, deny all of them. The clippy_pedantic group will control the rest of the lints as a group, but making all of them warn, for example, will make your compilation results full of warnings, due to false positives.

To use them, you simply need to use the group of lints as a lint:

#![deny(clippy)]

You can check the rest of the lints and configuration options in the Clippy wiki at https://rust-lang-nursery.github.io/rust-clippy/master/.