watchdog: imx7ulp: Watchdog should continue running for wait/stop mode

When kernel idle, system will enter wait/stop mode, wdog should continue
running in this scenario, and the refresh thread can wake up system from
wait/stop mode.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/1596150213-31638-2-git-send-email-Anson.Huang@nxp.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

drivers/watchdog/imx7ulp_wdt.c

@@ -22,6 +22,8 @@
 #define WDOG_CS_CLK		(LPO_CLK << LPO_CLK_SHIFT)
 #define WDOG_CS_EN		BIT(7)
 #define WDOG_CS_UPDATE		BIT(5)
+#define WDOG_CS_WAIT		BIT(1)
+#define WDOG_CS_STOP		BIT(0)
 
 #define WDOG_CNT	0x4
 #define WDOG_TOVAL	0x8
@@ -187,7 +189,8 @@ static int imx7ulp_wdt_init(void __iomem *base, unsigned int timeout)
 	/* set an initial timeout value in TOVAL */
 	writel(timeout, base + WDOG_TOVAL);
 	/* enable 32bit command sequence and reconfigure */
-	val = WDOG_CS_CMD32EN | WDOG_CS_CLK | WDOG_CS_UPDATE;
+	val = WDOG_CS_CMD32EN | WDOG_CS_CLK | WDOG_CS_UPDATE |
+	      WDOG_CS_WAIT | WDOG_CS_STOP;
 	writel(val, base + WDOG_CS);
 	imx7ulp_wdt_wait(base, WDOG_CS_RCS);