dt-bindings: display/msm: gpu: Document GMU wrapper-equipped A6xx

The "GMU Wrapper" is Qualcomm's name for "let's treat the GPU blocks
we'd normally assign to the GMU as if they were a part of the GMU, even
though they are not". It's a (good) software representation of the GMU_CX
and GMU_GX register spaces within the GPUSS that helps us programatically
treat these de-facto GMU-less parts in a way that's very similar to their
GMU-equipped cousins, massively saving up on code duplication.

The "wrapper" register space was specifically designed to mimic the layout
of a real GMU, though it rather obviously does not have the M3 core et al.

GMU wrapper-equipped A6xx GPUs require clocks and clock-names to be
specified under the GPU node, just like their older cousins. Account
for that.

Acked-by: Rob Herring <robh@kernel.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/542748/
Signed-off-by: Rob Clark <robdclark@chromium.org>

Documentation/devicetree/bindings/display/msm/gpu.yaml

@@ -36,10 +36,7 @@ properties:
 
   reg-names:
     minItems: 1
-    items:
-      - const: kgsl_3d0_reg_memory
-      - const: cx_mem
-      - const: cx_dbgc
+    maxItems: 3
 
   interrupts:
     maxItems: 1
@@ -157,16 +154,62 @@ allOf:
       required:
         - clocks
         - clock-names
+
   - if:
       properties:
         compatible:
           contains:
-            pattern: '^qcom,adreno-6[0-9][0-9]\.[0-9]$'
-
-    then: # Since Adreno 6xx series clocks should be defined in GMU
+            enum:
+              - qcom,adreno-610.0
+              - qcom,adreno-619.1
+    then:
       properties:
-        clocks: false
-        clock-names: false
+        clocks:
+          minItems: 6
+          maxItems: 6
+
+        clock-names:
+          items:
+            - const: core
+              description: GPU Core clock
+            - const: iface
+              description: GPU Interface clock
+            - const: mem_iface
+              description: GPU Memory Interface clock
+            - const: alt_mem_iface
+              description: GPU Alternative Memory Interface clock
+            - const: gmu
+              description: CX GMU clock
+            - const: xo
+              description: GPUCC clocksource clock
+
+        reg-names:
+          minItems: 1
+          items:
+            - const: kgsl_3d0_reg_memory
+            - const: cx_dbgc
+
+      required:
+        - clocks
+        - clock-names
+    else:
+      if:
+        properties:
+          compatible:
+            contains:
+              pattern: '^qcom,adreno-6[0-9][0-9]\.[0-9]$'
+
+      then: # Starting with A6xx, the clocks are usually defined in the GMU node
+        properties:
+          clocks: false
+          clock-names: false
+
+          reg-names:
+            minItems: 1
+            items:
+              - const: kgsl_3d0_reg_memory
+              - const: cx_mem
+              - const: cx_dbgc
 
 examples:
   - |