diff --git a/drivers/staging/speakup/speakup_acntpc.c b/drivers/staging/speakup/speakup_acntpc.c
index 87a508df7efb..80141aca712f 100644
--- a/drivers/staging/speakup/speakup_acntpc.c
+++ b/drivers/staging/speakup/speakup_acntpc.c
@@ -166,7 +166,7 @@ static const char *synth_immediate(struct spk_synth *synth, const char *buf)
 		outb_p(ch, speakup_info.port_tts);
 		buf++;
 	}
-	return 0;
+	return NULL;
 }
 
 static void do_catch_up(struct spk_synth *synth)