dt-bindings: watchdog: add i.MX system controller watchdog

Add i.MX system controller watchdog binding doc.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

diff --git a/Documentation/devicetree/bindings/watchdog/fsl-imx-sc-wdt.txt b/Documentation/devicetree/bindings/watchdog/fsl-imx-sc-wdt.txt
new file mode 100644 (file)
index 0000000..02b87e9
--- /dev/null
+++ b/Documentation/devicetree/bindings/watchdog/fsl-imx-sc-wdt.txt
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+* Freescale i.MX System Controller Watchdog
+
+i.MX system controller watchdog is for i.MX SoCs with system controller inside,
+the watchdog is managed by system controller, users can ONLY communicate with
+system controller from secure mode for watchdog operations, so Linux i.MX system
+controller watchdog driver will call ARM SMC API and trap into ARM-Trusted-Firmware
+for watchdog operations, ARM-Trusted-Firmware is running at secure EL3 mode and
+it will request system controller to execute the watchdog operation passed from
+Linux kernel.
+
+Required properties:
+- compatible:  Should be :
+               "fsl,imx8qxp-sc-wdt"
+               followed by "fsl,imx-sc-wdt";
+
+Optional properties:
+- timeout-sec : Contains the watchdog timeout in seconds.
+
+Examples:
+
+watchdog {
+       compatible = "fsl,imx8qxp-sc-wdt", "fsl,imx-sc-wdt";
+       timeout-sec = <60>;
+};