dt-bindings: fsl: scu: add rtc binding

NXP i.MX8QXP is an ARMv8 SoC with a Cortex-M4 core inside as
system controller, the system controller is in charge of system
power, clock and secure RTC etc. management, Linux kernel
has to communicate with system controller via MU (message unit)
IPC to do RTC operation, this patch adds binding doc for i.MX
system controller RTC driver.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/arm/freescale/fsl,scu.txt b/Documentation/devicetree/bindings/arm/freescale/fsl,scu.txt
index 46d0af1f0872..0860346fc9eb 100644
--- a/Documentation/devicetree/bindings/arm/freescale/fsl,scu.txt
+++ b/Documentation/devicetree/bindings/arm/freescale/fsl,scu.txt
@@ -114,6 +114,12 @@ Required properties for Pinctrl sub nodes:
 [2] Documentation/devicetree/bindings/power/power_domain.txt
 [3] Documentation/devicetree/bindings/pinctrl/fsl,imx-pinctrl.txt
 
+RTC bindings based on SCU Message Protocol
+------------------------------------------------------------
+
+Required properties:
+- compatible: should be "fsl,imx8qxp-sc-rtc";
+
 Example (imx8qxp):
 -------------
 lsio_mu1: mailbox@5d1c0000 {
@@ -169,6 +175,10 @@ firmware {
 			};
 			...
 		};
+
+		rtc: rtc {
+			compatible = "fsl,imx8qxp-sc-rtc";
+		};
 	};
 };