[PATCH v2 1/3] dt-bindings: watchdog: ti,rti-wdt: Add support for WDIOF_CARDRESET

[huaqian . li]

From: Li Hua Qian <huaqian.li@xxxxxxxxxxx>

TI RTI (Real Time Interrupt) Watchdog doesn't support to record the
watchdog cause. Add a reserved memory to know the last reboot was caused
by the watchdog card. In the reserved memory, some specific info will be
saved to indicate whether the watchdog reset was triggered in last
boot.

Signed-off-by: Li Hua Qian <huaqian.li@xxxxxxxxxxx>
---
 .../devicetree/bindings/watchdog/ti,rti-wdt.yaml    | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/watchdog/ti,rti-wdt.yaml b/Documentation/devicetree/bindings/watchdog/ti,rti-wdt.yaml
index fc553211e42d..f227db08dc70 100644
--- a/Documentation/devicetree/bindings/watchdog/ti,rti-wdt.yaml
+++ b/Documentation/devicetree/bindings/watchdog/ti,rti-wdt.yaml
@@ -26,7 +26,18 @@ properties:
       - ti,j7-rti-wdt
 
   reg:
-    maxItems: 1
+    maxItems: 2
+      description:
+	- Contains the address and the size of MCU RTI register.
+	- Contains the address and the size of reserved memory, which
+	  has the pre-stored watchdog reset cause as power-on reason. The
+	  second item is optional.
+	  In the reserved memory, the following values are needed at the
+	  first 12 bytes to tell that last boot was caused by watchdog
+	  reset.
+	  - PON_REASON_SOF_NUM:   0xBBBBCCCC
+	  - PON_REASON_MAGIC_NUM: 0xDDDDDDDD
+	  - PON_REASON_EOF_NUM:   0xCCCCBBBB
 
   clocks:
     maxItems: 1
-- 
2.34.1