non-recursive path limits

Is there a way to perform non-recursive path limiting on functions like 'git log', 'git format-patch', etc.

Each of these functions can limit to a path using the '-- <path>' notation. By default, it recursively goes down the directory tree. I would like to limit the tree descent to one level. For example,

repos/a-dir/a1.c repos/a-dir/a2.c repos/a-dir/a-lib/alib1.c repos/a-dir/a-lib/alib2.c

If we are in repos, then 'git log -- a-dir' will show all four files. However, I only wish to see the output for all files that are the 'a-dir' level. For the above, that would consist of a1.c and a2.c. However, I also wish to see any files that might have existed in the history at this level. I know I can do 'git log -- a-dir/a1.c' to search all history for the a1.c file, but I want the history of the a-dir directory (only).

Is there a way to accomplish this?

Thanks,

Paul