\documentclass{article}
\usepackage{tikz}
\NewDocumentCommand{\test}{ >{\SplitArgument{2}{,}}O{red,brown} m }{%
\begin{tikzpicture}
\node[minimum size=11mm, draw,
label={[text=#1]up},
label={[text=#2]below:down}
]{#3};
\end{tikzpicture}
}%
\begin{document}
\test{text}
\test[blue, red]{text}
\end{document}