drivers are "in box" together with the kernel Linux.
here for example the contents of the package additional kernel modules linux-modules-extra-generic
all that is in the directory kernel/drivers are just kernel modules with specific iron the code - in common driver :)
in Linux in General, almost all comes in the box along with the operating system in the repository.
there is almost everything available under the operating system, software, and plus more with updates.
although of course support for Linux from hardware manufacturers is weaker :(