dt-bindings: display: msm: gmu: add optional ocmem property

Some A3xx and A4xx Adreno GPUs do not have GMEM inside the GPU core and
must use the On Chip MEMory (OCMEM) in order to be functional. Add the
optional ocmem property to the Adreno Graphics Management Unit bindings.
Signed-off-by: NBrian Masney <masneyb@onstation.org>
Reviewed-by: NRob Herring <robh@kernel.org>
Signed-off-by: NRob Clark <robdclark@chromium.org>

Documentation/devicetree/bindings/display/msm/gmu.txt

@@ -31,6 +31,10 @@ Required properties:
 - iommus: phandle to the adreno iommu
 - operating-points-v2: phandle to the OPP operating points
 
+Optional properties:
+- sram: phandle to the On Chip Memory (OCMEM) that's present on some Snapdragon
+        SoCs. See Documentation/devicetree/bindings/sram/qcom,ocmem.yaml.
+
 Example:
 
 / {
@@ -63,3 +67,50 @@ Example:
 		operating-points-v2 = <&gmu_opp_table>;
 	};
 };
+
+a3xx example with OCMEM support:
+
+/ {
+	...
+
+	gpu: adreno@fdb00000 {
+		compatible = "qcom,adreno-330.2",
+		             "qcom,adreno";
+		reg = <0xfdb00000 0x10000>;
+		reg-names = "kgsl_3d0_reg_memory";
+		interrupts = <GIC_SPI 33 IRQ_TYPE_LEVEL_HIGH>;
+		interrupt-names = "kgsl_3d0_irq";
+		clock-names = "core",
+		              "iface",
+		              "mem_iface";
+		clocks = <&mmcc OXILI_GFX3D_CLK>,
+		         <&mmcc OXILICX_AHB_CLK>,
+		         <&mmcc OXILICX_AXI_CLK>;
+		sram = <&gmu_sram>;
+		power-domains = <&mmcc OXILICX_GDSC>;
+		operating-points-v2 = <&gpu_opp_table>;
+		iommus = <&gpu_iommu 0>;
+	};
+
+	ocmem@fdd00000 {
+		compatible = "qcom,msm8974-ocmem";
+
+		reg = <0xfdd00000 0x2000>,
+		      <0xfec00000 0x180000>;
+		reg-names = "ctrl",
+		             "mem";
+
+		clocks = <&rpmcc RPM_SMD_OCMEMGX_CLK>,
+		         <&mmcc OCMEMCX_OCMEMNOC_CLK>;
+		clock-names = "core",
+		              "iface";
+
+		#address-cells = <1>;
+		#size-cells = <1>;
+
+		gmu_sram: gmu-sram@0 {
+			reg = <0x0 0x100000>;
+			ranges = <0 0 0xfec00000 0x100000>;
+		};
+	};
+};