ARM: dts: meson: add the hardware random number generator

All supported Meson SoCs have a random number generator in CBUS.
Newer SoCs (GXBB, GXL and GXM) provide only one 32-bit random number
register, whereas the older SoCs (Meson6, Meson8 and Meson8b) have two
32-bit random number registers. The existing meson-rng driver only
supports the lower 32-bit - but it still works fine on the older SoCs
apart from this small limitation.

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>

arch/arm/boot/dts/meson.dtsi

@@ -80,6 +80,11 @@
 			#size-cells = <1>;
 			ranges = <0x0 0xc1100000 0x200000>;
 
+			hwrng: rng@8100 {
+				compatible = "amlogic,meson-rng";
+				reg = <0x8100 0x8>;
+			};
+
 			uart_A: serial@84c0 {
 				compatible = "amlogic,meson-uart";
 				reg = <0x84c0 0x18>;

arch/arm/boot/dts/meson8.dtsi

@@ -241,6 +241,12 @@
 	clock-names = "stmmaceth";
 };
 
+&hwrng {
+	compatible = "amlogic,meson8-rng", "amlogic,meson-rng";
+	clocks = <&clkc CLKID_RNG0>;
+	clock-names = "core";
+};
+
 &i2c_AO {
 	clocks = <&clkc CLKID_CLK81>;
 };

arch/arm/boot/dts/meson8b.dtsi

@@ -171,6 +171,12 @@
 	};
 };
 
+&hwrng {
+	compatible = "amlogic,meson8b-rng", "amlogic,meson-rng";
+	clocks = <&clkc CLKID_RNG0>;
+	clock-names = "core";
+};
+
 &L2 {
 	arm,data-latency = <3 3 3>;
 	arm,tag-latency = <2 2 2>;