watchdog: core: dt: add support for the timeout-sec dt property

Add support for watchdog drivers to initialize/set the timeout field
of the watchdog_device structure. The timeout field is initialised
either with the module timeout parameter value (if valid) or with the
timeout-sec dt property (if valid). If both are invalid the initial
value is unchanged.

Signed-off-by: Fabio Porcedda <fabio.porcedda@gmail.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

1 files changed, 57 insertions, 9 deletions

diff --git a/drivers/watchdog/watchdog_core.c b/drivers/watchdog/watchdog_core.c
index 3796434991fa..05d18b4c661b 100644
--- a/drivers/watchdog/watchdog_core.c
+++ b/drivers/watchdog/watchdog_core.c
@@ -36,12 +36,68 @@
 #include <linux/init.h>         /* For __init/__exit/... */
 #include <linux/idr.h>          /* For ida_* macros */
 #include <linux/err.h>          /* For IS_ERR macros */
+#include <linux/of.h>           /* For of_get_timeout_sec */
 
 #include "watchdog_core.h"      /* For watchdog_dev_register/... */
 
 static DEFINE_IDA(watchdog_ida);
 static struct class *watchdog_class;
 
+static void watchdog_check_min_max_timeout(struct watchdog_device *wdd)
+{
+        /*
+         * Check that we have valid min and max timeout values, if
+         * not reset them both to 0 (=not used or unknown)
+         */
+        if (wdd->min_timeout > wdd->max_timeout) {
+                pr_info("Invalid min and max timeout values, resetting to 0!\n");
+                wdd->min_timeout = 0;
+                wdd->max_timeout = 0;
+        }
+}
+
+/**
+ * watchdog_init_timeout() - initialize the timeout field
+ * @timeout_parm: timeout module parameter
+ * @dev: Device that stores the timeout-sec property
+ *
+ * Initialize the timeout field of the watchdog_device struct with either the
+ * timeout module parameter (if it is valid value) or the timeout-sec property
+ * (only if it is a valid value and the timeout_parm is out of bounds).
+ * If none of them are valid then we keep the old value (which should normally
+ * be the default timeout value.
+ *
+ * A zero is returned on success and -EINVAL for failure.
+ */
+int watchdog_init_timeout(struct watchdog_device *wdd,
+                                unsigned int timeout_parm, struct device *dev)
+{
+        unsigned int t = 0;
+        int ret = 0;
+
+        watchdog_check_min_max_timeout(wdd);
+
+        /* try to get the tiemout module parameter first */
+        if (!watchdog_timeout_invalid(wdd, timeout_parm)) {
+                wdd->timeout = timeout_parm;
+                return ret;
+        }
+        if (timeout_parm)
+                ret = -EINVAL;
+
+        /* try to get the timeout_sec property */
+        if (dev == NULL || dev->of_node == NULL)
+                return ret;
+        of_property_read_u32(dev->of_node, "timeout-sec", &t);
+        if (!watchdog_timeout_invalid(wdd, t))
+                wdd->timeout = t;
+        else
+                ret = -EINVAL;
+
+        return ret;
+}
+EXPORT_SYMBOL_GPL(watchdog_init_timeout);
+
 /**
  * watchdog_register_device() - register a watchdog device
  * @wdd: watchdog device
@@ -63,15 +119,7 @@ int watchdog_register_device(struct watchdog_device *wdd)
         if (wdd->ops->start == NULL || wdd->ops->stop == NULL)
                 return -EINVAL;
 
-        /*
-         * Check that we have valid min and max timeout values, if
-         * not reset them both to 0 (=not used or unknown)
-         */
-        if (wdd->min_timeout > wdd->max_timeout) {
-                pr_info("Invalid min and max timeout values, resetting to 0!\n");
-                wdd->min_timeout = 0;
-                wdd->max_timeout = 0;
-        }
+        watchdog_check_min_max_timeout(wdd);
 
         /*
          * Note: now that all watchdog_device data has been verified, we