watchdog: ftwdt010_wdt: implement _restart() function

Implement ftwdt010_wdt_restart(). It enables watchdog with timeout = 0
and disabled IRQ. Since it needs code similar to ftwdt010_wdt_start(),
add a new function ftwdt010_enable() and move common code there.
Suggested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Sergei Antonov <saproj@gmail.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20220829090436.452742-1-saproj@gmail.comSigned-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

drivers/watchdog/ftwdt010_wdt.c

@@ -47,21 +47,28 @@ struct ftwdt010_wdt *to_ftwdt010_wdt(struct watchdog_device *wdd)
 	return container_of(wdd, struct ftwdt010_wdt, wdd);
 }
 
-static int ftwdt010_wdt_start(struct watchdog_device *wdd)
+static void ftwdt010_enable(struct ftwdt010_wdt *gwdt,
+			    unsigned int timeout,
+			    bool need_irq)
 {
-	struct ftwdt010_wdt *gwdt = to_ftwdt010_wdt(wdd);
 	u32 enable;
 
-	writel(wdd->timeout * WDT_CLOCK, gwdt->base + FTWDT010_WDLOAD);
+	writel(timeout * WDT_CLOCK, gwdt->base + FTWDT010_WDLOAD);
 	writel(WDRESTART_MAGIC, gwdt->base + FTWDT010_WDRESTART);
 	/* set clock before enabling */
 	enable = WDCR_CLOCK_5MHZ | WDCR_SYS_RST;
 	writel(enable, gwdt->base + FTWDT010_WDCR);
-	if (gwdt->has_irq)
+	if (need_irq)
 		enable |= WDCR_WDINTR;
 	enable |= WDCR_ENABLE;
 	writel(enable, gwdt->base + FTWDT010_WDCR);
+}
 
+static int ftwdt010_wdt_start(struct watchdog_device *wdd)
+{
+	struct ftwdt010_wdt *gwdt = to_ftwdt010_wdt(wdd);
+
+	ftwdt010_enable(gwdt, wdd->timeout, gwdt->has_irq);
 	return 0;
 }
 
@@ -93,6 +100,13 @@ static int ftwdt010_wdt_set_timeout(struct watchdog_device *wdd,
 	return 0;
 }
 
+static int ftwdt010_wdt_restart(struct watchdog_device *wdd,
+				unsigned long action, void *data)
+{
+	ftwdt010_enable(to_ftwdt010_wdt(wdd), 0, false);
+	return 0;
+}
+
 static irqreturn_t ftwdt010_wdt_interrupt(int irq, void *data)
 {
 	struct ftwdt010_wdt *gwdt = data;
@@ -107,6 +121,7 @@ static const struct watchdog_ops ftwdt010_wdt_ops = {
 	.stop		= ftwdt010_wdt_stop,
 	.ping		= ftwdt010_wdt_ping,
 	.set_timeout	= ftwdt010_wdt_set_timeout,
+	.restart	= ftwdt010_wdt_restart,
 	.owner		= THIS_MODULE,
 };