diff --git a/arch/arm/plat-s3c64xx/s3c6400-clock.c b/arch/arm/plat-s3c64xx/s3c6400-clock.c
index f8165e622478..febac1950d8e 100644
--- a/arch/arm/plat-s3c64xx/s3c6400-clock.c
+++ b/arch/arm/plat-s3c64xx/s3c6400-clock.c
@@ -175,7 +175,7 @@ static int s3c64xx_clk_arm_set_rate(struct clk *clk, unsigned long rate)
 	div = clk_get_rate(clk->parent) / rate;
 
 	val = __raw_readl(S3C_CLK_DIV0);
-	val &= armclk_mask;
+	val &= ~armclk_mask;
 	val |= (div - 1);
 	__raw_writel(val, S3C_CLK_DIV0);