diff --git a/drivers/pwm/pwm-sun4i.c b/drivers/pwm/pwm-sun4i.c
index 6f5840a..0527372 100644
--- a/drivers/pwm/pwm-sun4i.c
+++ b/drivers/pwm/pwm-sun4i.c
@@ -137,10 +137,10 @@
 
 	val = sun4i_pwm_readl(sun4i_pwm, PWM_CH_PRD(pwm->hwpwm));
 
-	tmp = prescaler * NSEC_PER_SEC * PWM_REG_DTY(val);
+	tmp = (u64)prescaler * NSEC_PER_SEC * PWM_REG_DTY(val);
 	state->duty_cycle = DIV_ROUND_CLOSEST_ULL(tmp, clk_rate);
 
-	tmp = prescaler * NSEC_PER_SEC * PWM_REG_PRD(val);
+	tmp = (u64)prescaler * NSEC_PER_SEC * PWM_REG_PRD(val);
 	state->period = DIV_ROUND_CLOSEST_ULL(tmp, clk_rate);
 }