diff --git a/drivers/pwm/pwm-jz4740.c b/drivers/pwm/pwm-jz4740.c
index 9d78cc2..77c2831 100644
--- a/drivers/pwm/pwm-jz4740.c
+++ b/drivers/pwm/pwm-jz4740.c
@@ -92,11 +92,12 @@
 {
 	struct jz4740_pwm_chip *jz4740 = to_jz4740(pwm->chip);
 	unsigned long long tmp;
-	unsigned long period, duty;
+	unsigned long rate, period, duty;
 	unsigned int prescaler = 0;
 	uint16_t ctrl;
 
-	tmp = (unsigned long long)clk_get_rate(jz4740->clk) * state->period;
+	rate = clk_get_rate(jz4740->clk);
+	tmp = rate * state->period;
 	do_div(tmp, 1000000000);
 	period = tmp;
 
@@ -108,8 +109,8 @@
 	if (prescaler == 6)
 		return -EINVAL;
 
-	tmp = (unsigned long long)period * state->duty_cycle;
-	do_div(tmp, state->period);
+	tmp = (unsigned long long)rate * state->duty_cycle;
+	do_div(tmp, NSEC_PER_SEC);
 	duty = period - tmp;
 
 	if (duty >= period)