From e0f18128bfd23c99a060a5f931c1bcaa6afdab6a Mon Sep 17 00:00:00 2001
From: Nick Ward <nick.ward@setec.com.au>
Date: Fri, 10 Sep 2021 22:50:47 +1000
Subject: [PATCH] task_wdt: fix silent init failures

The task_wdt_init() API can fail to install a timeout for the fallback
hardware WDT (hw_wdt) without returning an error code.  This patch
enables task_wdt_init() to return the hw_wdt install timeout error code
if the hw_wdt install timeout fails.

Signed-off-by: Nick Ward <nick.ward@setec.com.au>
---
 include/task_wdt/task_wdt.h        | 3 +++
 samples/subsys/task_wdt/src/main.c | 8 +++++++-
 subsys/task_wdt/task_wdt.c         | 4 ++++
 3 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/include/task_wdt/task_wdt.h b/include/task_wdt/task_wdt.h
index cd3ba078315..68d488b3738 100644
--- a/include/task_wdt/task_wdt.h
+++ b/include/task_wdt/task_wdt.h
@@ -47,6 +47,9 @@ typedef void (*task_wdt_callback_t)(int channel_id, void *user_data);
  *
  * @retval 0 If successful.
  * @retval -ENOTSUP If assigning a hardware watchdog is not supported.
+ * @retval -Errno Negative errno if the fallback hw_wdt is used and the
+ *                install timeout API fails.  See wdt_install_timeout()
+ *                API for possible return values.
  */
 int task_wdt_init(const struct device *hw_wdt);
 
diff --git a/samples/subsys/task_wdt/src/main.c b/samples/subsys/task_wdt/src/main.c
index 2855d1068a4..c5c3bdf7e4c 100644
--- a/samples/subsys/task_wdt/src/main.c
+++ b/samples/subsys/task_wdt/src/main.c
@@ -58,6 +58,7 @@ static void task_wdt_callback(int channel_id, void *user_data)
 
 void main(void)
 {
+	int ret;
 #ifdef WDT_NODE
 	const struct device *hw_wdt_dev = DEVICE_DT_GET(WDT_NODE);
 #else
@@ -72,7 +73,12 @@ void main(void)
 		hw_wdt_dev = NULL;
 	}
 
-	task_wdt_init(hw_wdt_dev);
+	ret = task_wdt_init(hw_wdt_dev);
+	if (ret != 0) {
+		printk("task wdt init failure: %d\n", ret);
+		return;
+	}
+
 
 	/* passing NULL instead of callback to trigger system reset */
 	int task_wdt_id = task_wdt_add(1100U, NULL, NULL);
diff --git a/subsys/task_wdt/task_wdt.c b/subsys/task_wdt/task_wdt.c
index 71219182bbb..7941313be97 100644
--- a/subsys/task_wdt/task_wdt.c
+++ b/subsys/task_wdt/task_wdt.c
@@ -136,6 +136,10 @@ int task_wdt_init(const struct device *hw_wdt)
 
 		hw_wdt_dev = hw_wdt;
 		hw_wdt_channel = wdt_install_timeout(hw_wdt_dev, &wdt_config);
+		if (hw_wdt_channel < 0) {
+			LOG_ERR("hw_wdt install timeout failed: %d", hw_wdt_channel);
+			return hw_wdt_channel;
+		}
 #else
 		return -ENOTSUP;
 #endif