diff --git a/drivers/watchdog/renesas_wdt.c b/drivers/watchdog/renesas_wdt.c
index 88d81feba4e60087fe52b85b7438b83f0dbc07a8..d01efd342dc0c246b6d9874d7a856afd96c7e14a 100644
--- a/drivers/watchdog/renesas_wdt.c
+++ b/drivers/watchdog/renesas_wdt.c
@@ -77,12 +77,17 @@ static int rwdt_init_timeout(struct watchdog_device *wdev)
 static int rwdt_start(struct watchdog_device *wdev)
 {
 	struct rwdt_priv *priv = watchdog_get_drvdata(wdev);
+	u8 val;
 
 	pm_runtime_get_sync(wdev->parent);
 
-	rwdt_write(priv, 0, RWTCSRB);
-	rwdt_write(priv, priv->cks, RWTCSRA);
+	/* Stop the timer before we modify any register */
+	val = readb_relaxed(priv->base + RWTCSRA) & ~RWTCSRA_TME;
+	rwdt_write(priv, val, RWTCSRA);
+
 	rwdt_init_timeout(wdev);
+	rwdt_write(priv, priv->cks, RWTCSRA);
+	rwdt_write(priv, 0, RWTCSRB);
 
 	while (readb_relaxed(priv->base + RWTCSRA) & RWTCSRA_WRFLG)
 		cpu_relax();