diff --git a/drivers/staging/r8188eu/core/rtw_rf.c b/drivers/staging/r8188eu/core/rtw_rf.c
index 2ec56012516e..e704092d31d0 100644
--- a/drivers/staging/r8188eu/core/rtw_rf.c
+++ b/drivers/staging/r8188eu/core/rtw_rf.c
@@ -35,7 +35,7 @@ static struct ch_freq ch_freq_map[] = {
{216, 5080},/* Japan, means J16 */
};
-static int ch_freq_map_num = (sizeof(ch_freq_map) / sizeof(struct ch_freq));
+static int ch_freq_map_num = ARRAY_SIZE(ch_freq_map);
u32 rtw_ch2freq(u32 channel)
{