watchdog: sp5100-tco: Abort if watchdog is disabled by hardware

If the watchdog control register indicates that the watchdog hardware
is disabled even after we tried to enable it, there is no point to
instantiate the driver.

Cc: Zoltán Böszörményi <zboszor@pr.hu>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

diff --git a/drivers/watchdog/sp5100_tco.c b/drivers/watchdog/sp5100_tco.c
index bb6c460..23246cb 100644 (file)
--- a/drivers/watchdog/sp5100_tco.c
+++ b/drivers/watchdog/sp5100_tco.c
@@ -273,14 +273,20 @@ static int sp5100_tco_setupdevice(struct device *dev,
        /* Setup the watchdog timer */
        tco_timer_enable();
 
-       /* Check that the watchdog action is set to reset the system */
        val = readl(SP5100_WDT_CONTROL(tco->tcobase));
+       if (val & SP5100_WDT_DISABLED) {
+               dev_err(dev, "Watchdog hardware is disabled\n");
+               ret = -ENODEV;
+               goto unreg_region;
+       }
+
        /*
         * Save WatchDogFired status, because WatchDogFired flag is
         * cleared here.
         */
        if (val & SP5100_WDT_FIRED)
                wdd->bootstatus = WDIOF_CARDRESET;
+       /* Set watchdog action to reset the system */
        val &= ~SP5100_WDT_ACTION_RESET;
        writel(val, SP5100_WDT_CONTROL(tco->tcobase));
 

diff --git a/drivers/watchdog/sp5100_tco.h b/drivers/watchdog/sp5100_tco.h
index ca0721c..008b209 100644 (file)
--- a/drivers/watchdog/sp5100_tco.h
+++ b/drivers/watchdog/sp5100_tco.h
@@ -19,6 +19,7 @@
 #define SP5100_WDT_START_STOP_BIT      BIT(0)
 #define SP5100_WDT_FIRED               BIT(1)
 #define SP5100_WDT_ACTION_RESET                BIT(2)
+#define SP5100_WDT_DISABLED            BIT(3)
 #define SP5100_WDT_TRIGGER_BIT         BIT(7)
 
 #define SP5100_PM_IOPORTS_SIZE         0x02