diff --git a/drivers/clk/at91/clk-master.c b/drivers/clk/at91/clk-master.c
index 9a2c8e64cacf..2093e13b5068 100644
--- a/drivers/clk/at91/clk-master.c
+++ b/drivers/clk/at91/clk-master.c
@@ -344,7 +344,7 @@ static int clk_master_pres_set_rate(struct clk_hw *hw, unsigned long rate,
 
 	else if (pres == 3)
 		pres = MASTER_PRES_MAX;
-	else
+	else if (pres)
 		pres = ffs(pres) - 1;
 
 	spin_lock_irqsave(master->lock, flags);
@@ -757,7 +757,7 @@ static int clk_sama7g5_master_set_rate(struct clk_hw *hw, unsigned long rate,
 
 	if (div == 3)
 		div = MASTER_PRES_MAX;
-	else
+	else if (div)
 		div = ffs(div) - 1;
 
 	spin_lock_irqsave(master->lock, flags);