dt-bindings: arm: Extend SCMI to support new reset protocol

SCMIv2.0 adds a new Reset Management Protocol to manage various reset
states a given device or domain can enter. Extend the existing SCMI
bindings to add reset protocol support by re-using the reset bindings
for both reset providers and consumers.

Cc: Philipp Zabel <p.zabel@pengutronix.de>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: devicetree@vger.kernel.org
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

Documentation/devicetree/bindings/arm/arm,scmi.txt

@@ -73,6 +73,16 @@ Required properties:
 			 as used by the firmware. Refer to  platform details
 			 for your implementation for the IDs to use.
 
+Reset signal bindings for the reset domains based on SCMI Message Protocol
+------------------------------------------------------------
+
+This binding for the SCMI reset domain providers uses the generic reset
+signal binding[5].
+
+Required properties:
+ - #reset-cells : Should be 1. Contains the reset domain ID value used
+		  by SCMI commands.
+
 SRAM and Shared Memory for SCMI
 -------------------------------
 
@@ -93,6 +103,7 @@ Required sub-node properties:
 [2] Documentation/devicetree/bindings/power/power_domain.txt
 [3] Documentation/devicetree/bindings/thermal/thermal.txt
 [4] Documentation/devicetree/bindings/sram/sram.txt
+[5] Documentation/devicetree/bindings/reset/reset.txt
 
 Example:
 
@@ -152,6 +163,11 @@ firmware {
 			reg = <0x15>;
 			#thermal-sensor-cells = <1>;
 		};
+
+		scmi_reset: protocol@16 {
+			reg = <0x16>;
+			#reset-cells = <1>;
+		};
 	};
 };
 
@@ -166,6 +182,7 @@ hdlcd@7ff60000 {
 	reg = <0 0x7ff60000 0 0x1000>;
 	clocks = <&scmi_clk 4>;
 	power-domains = <&scmi_devpd 1>;
+	resets = <&scmi_reset 10>;
 };
 
 thermal-zones {