arm64: dts: amlogic: meson-gxm: add the Mali OPP table and use DVFS

Add the OPP table for the Mali-T820 GPU and drop the hardcoded initial
clock configuration. This enables GPU DVFS and thus saves power when the
GPU is not in use while still being able switch to a higher clock on
demand.
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>
Link: https://lore.kernel.org/r/20200719173213.639540-3-martin.blumenstingl@googlemail.com

arch/arm64/boot/dts/amlogic/meson-gxm.dtsi

@@ -82,6 +82,35 @@ cpu7: cpu@103 {
 			#cooling-cells = <2>;
 		};
 	};
+
+	gpu_opp_table: opp-table {
+		compatible = "operating-points-v2";
+
+		opp-125000000 {
+			opp-hz = /bits/ 64 <125000000>;
+			opp-microvolt = <950000>;
+		};
+		opp-250000000 {
+			opp-hz = /bits/ 64 <250000000>;
+			opp-microvolt = <950000>;
+		};
+		opp-285714285 {
+			opp-hz = /bits/ 64 <285714285>;
+			opp-microvolt = <950000>;
+		};
+		opp-400000000 {
+			opp-hz = /bits/ 64 <400000000>;
+			opp-microvolt = <950000>;
+		};
+		opp-500000000 {
+			opp-hz = /bits/ 64 <500000000>;
+			opp-microvolt = <950000>;
+		};
+		opp-666666666 {
+			opp-hz = /bits/ 64 <666666666>;
+			opp-microvolt = <950000>;
+		};
+	};
 };
 
 &apb {
@@ -106,21 +135,7 @@ mali: gpu@c0000 {
 		interrupt-names = "job", "mmu", "gpu";
 		clocks = <&clkc CLKID_MALI>;
 		resets = <&reset RESET_MALI_CAPB3>, <&reset RESET_MALI>;
-
-		/*
-		 * Mali clocking is provided by two identical clock paths
-		 * MALI_0 and MALI_1 muxed to a single clock by a glitch
-		 * free mux to safely change frequency while running.
-		 */
-		assigned-clocks = <&clkc CLKID_MALI_0_SEL>,
-				  <&clkc CLKID_MALI_0>,
-				  <&clkc CLKID_MALI>; /* Glitch free mux */
-		assigned-clock-parents = <&clkc CLKID_FCLK_DIV3>,
-					 <0>, /* Do Nothing */
-					 <&clkc CLKID_MALI_0>;
-		assigned-clock-rates = <0>, /* Do Nothing */
-				       <666666666>,
-				       <0>; /* Do Nothing */
+		operating-points-v2 = <&gpu_opp_table>;
 	};
 };