diff --git a/drivers/clocksource/timer-atmel-tcb.c b/drivers/clocksource/timer-atmel-tcb.c
index 27af17c99590..2a90c92a9182 100644
--- a/drivers/clocksource/timer-atmel-tcb.c
+++ b/drivers/clocksource/timer-atmel-tcb.c
@@ -315,6 +315,7 @@ static void __init tcb_setup_dual_chan(struct atmel_tc *tc, int mck_divisor_idx)
 	writel(mck_divisor_idx			/* likely divide-by-8 */
 			| ATMEL_TC_WAVE
 			| ATMEL_TC_WAVESEL_UP		/* free-run */
+			| ATMEL_TC_ASWTRG_SET		/* TIOA0 rises at software trigger */
 			| ATMEL_TC_ACPA_SET		/* TIOA0 rises at 0 */
 			| ATMEL_TC_ACPC_CLEAR,		/* (duty cycle 50%) */
 			tcaddr + ATMEL_TC_REG(0, CMR));