diff --git a/drivers/pwm/pwm-tiecap.c b/drivers/pwm/pwm-tiecap.c
index 081471f..d6d4cf0 100644
--- a/drivers/pwm/pwm-tiecap.c
+++ b/drivers/pwm/pwm-tiecap.c
@@ -60,7 +60,7 @@
 	unsigned long period_cycles, duty_cycles;
 	unsigned int reg_val;
 
-	if (period_ns < 0 || duty_ns < 0 || period_ns > NSEC_PER_SEC)
+	if (period_ns > NSEC_PER_SEC)
 		return -ERANGE;
 
 	c = pc->clk_rate;