diff --git a/arch/arm/plat-s3c64xx/s3c6400-clock.c b/arch/arm/plat-s3c64xx/s3c6400-clock.c
index 6edbeef6aa9df593850c8e6d8bf664218199f672..05b17528041e36f451e4bc5f0e30b8d33ab316ea 100644
--- a/arch/arm/plat-s3c64xx/s3c6400-clock.c
+++ b/arch/arm/plat-s3c64xx/s3c6400-clock.c
@@ -239,10 +239,12 @@ static int s3c64xx_setrate_clksrc(struct clk *clk, unsigned long rate)
 
 	rate = clk_round_rate(clk, rate);
 	div = clk_get_rate(clk->parent) / rate;
+	if (div > 16)
+		return -EINVAL;
 
 	val = __raw_readl(reg);
-	val &= ~sclk->mask;
-	val |= (rate - 1) << sclk->shift;
+	val &= ~(0xf << sclk->shift);
+	val |= (div - 1) << sclk->shift;
 	__raw_writel(val, reg);
 
 	return 0;