watchdog: dw_wdt: add stop watchdog operation

The only way of stopping the watchdog is by resetting it.
Add the watchdog op for stopping the device and reset if
a reset line is provided.

At same time WDOG_HW_RUNNING should be remove from dw_wdt_start.
As commented by Guenter Roeck:
dw_wdt sets WDOG_HW_RUNNING in its open function. Result is
that the kref_get() in watchdog_open() won't be executed. But then
kref_put() in close will be called since the watchdog now does stop.
This causes the imbalance.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Cc: Wim Van Sebroeck <wim@iguana.be>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: linux-watchdog@vger.kernel.org
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

diff --git a/drivers/watchdog/dw_wdt.c b/drivers/watchdog/dw_wdt.c
index 36be987ff9efc11290a036740aef16bd0fc96e72..c2f4ff51623015ca32aca20d3ad74ff05fe38e29 100644 (file)
--- a/drivers/watchdog/dw_wdt.c
+++ b/drivers/watchdog/dw_wdt.c
@@ -127,14 +127,27 @@ static int dw_wdt_start(struct watchdog_device *wdd)
 
        dw_wdt_set_timeout(wdd, wdd->timeout);
 
-       set_bit(WDOG_HW_RUNNING, &wdd->status);
-
        writel(WDOG_CONTROL_REG_WDT_EN_MASK,
               dw_wdt->regs + WDOG_CONTROL_REG_OFFSET);
 
        return 0;
 }
 
+static int dw_wdt_stop(struct watchdog_device *wdd)
+{
+       struct dw_wdt *dw_wdt = to_dw_wdt(wdd);
+
+       if (!dw_wdt->rst) {
+               set_bit(WDOG_HW_RUNNING, &wdd->status);
+               return 0;
+       }
+
+       reset_control_assert(dw_wdt->rst);
+       reset_control_deassert(dw_wdt->rst);
+
+       return 0;
+}
+
 static int dw_wdt_restart(struct watchdog_device *wdd,
                          unsigned long action, void *data)
 {
@@ -173,6 +186,7 @@ static const struct watchdog_info dw_wdt_ident = {
 static const struct watchdog_ops dw_wdt_ops = {
        .owner          = THIS_MODULE,
        .start          = dw_wdt_start,
+       .stop           = dw_wdt_stop,
        .ping           = dw_wdt_ping,
        .set_timeout    = dw_wdt_set_timeout,
        .get_timeleft   = dw_wdt_get_timeleft,