Beginner question: Package documentation?

I've downloaded a couple of packages using asdf-install, but I can't find the documentation for them online anywhere. Is there a way to view documentation for package from a repl? For instance, is there a function that will print a list of all the functions provided by a package? I've tried to use 'documentation', but I can't figure out how to use it on packages from clhs (I tried (documentation 'package-name 'package) without success).
Help would be much appreciated. Thanks!

No, not that I know of. There are the standard Lisp functions for viewing doc strings and such, but those only operate at the symbol level, not the ASDF package level.

You can try tinaa to auto-generate a html files with the functions and their docs. It seems to work this way:

(tinaa:document-system 'asdf-system 'the-name-of-the-system-here "/path/to/somewhere")

See the documentation of this function for other uses or more detail.

tinaa looks sweet, but unfortunately I get

The function METABANG.UTILITIES:DIRECTORY-NAME-P is undefined.
   [Condition of type UNDEFINED-FUNCTION]

every time I try to use it. I installed it with asdf-install, but I think I might have messed something up.

However, in emacs, slime-apropros-package does exactly what I was looking for. It does seem sort of strange that (documentation ...) doesn't do this.
Thanks anyway!