How to define Proportional Integral (PI) controller as a function (from script), to generate C code?

The general form of PI controller is Kp+ Ki/S (laplace).

I used this following code:

function s=controller(kp,ki)

s = tf([kp ki],[1 0])

but when I convert it into C code, I get this error:

The 'tf' class does not support code generation.

I need to code PI controller in C language, Do you have any suggestion to solve the problem?

Thank you