watchdog: make DesignWare watchdog allow users to set bigger timeout value

watchdog_dev.c provides means to allow users to set bigger timeout value
than HW can support, make DesignWare watchdog align with this.
Signed-off-by: Peng Wang <peng.1.wang@nokia-sbell.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/8fa54e92c6cd4544a7a3eb60a373ac43@nokia-sbell.comSigned-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

drivers/watchdog/dw_wdt.c

@@ -114,7 +114,15 @@ static int dw_wdt_set_timeout(struct watchdog_device *wdd, unsigned int top_s)
 	writel(top_val | top_val << WDOG_TIMEOUT_RANGE_TOPINIT_SHIFT,
 	       dw_wdt->regs + WDOG_TIMEOUT_RANGE_REG_OFFSET);
 
-	wdd->timeout = dw_wdt_top_in_seconds(dw_wdt, top_val);
+	/*
+	 * In case users set bigger timeout value than HW can support,
+	 * kernel(watchdog_dev.c) helps to feed watchdog before
+	 * wdd->max_hw_heartbeat_ms
+	 */
+	if (top_s * 1000 <= wdd->max_hw_heartbeat_ms)
+		wdd->timeout = dw_wdt_top_in_seconds(dw_wdt, top_val);
+	else
+		wdd->timeout = top_s;
 
 	return 0;
 }