dt-bindings: display: msm: Add reg bus and rotator interconnects

Apart from the already handled data bus (MAS_MDP_Pn<->DDR), there are
other connection paths:
- a path that connects rotator block to the DDR.
- a path that needs to be handled to ensure MDSS register access
functions properly, namely the "reg bus", a.k.a the CPU-MDSS CFG
interconnect.

Describe these paths to allow using them in device trees and in the
driver.

[Konrad: rework for one vs two MDP paths, update examples]
Reviewed-by: Krzysztof Kozlowski <[e-mail]>
Signed-off-by: Konrad Dybcio <[e-mail]>
Patchwork: https://patchwork.freedesktop.org/patch/569480/
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Dmitry Baryshkov <[e-mail]>

Documentation/devicetree/bindings/display/msm/mdss-common.yaml

···
 
   ranges: true
 
+  # This is not a perfect description, but it's impossible to discern and match
+  # the entries like we do with interconnect-names
   interconnects:
     minItems: 1
     items:
       - description: Interconnect path from mdp0 (or a single mdp) port to the data bus
       - description: Interconnect path from mdp1 port to the data bus
+      - description: Interconnect path from CPU to the reg bus
 
   interconnect-names:
-    minItems: 1
-    items:
-      - const: mdp0-mem
-      - const: mdp1-mem
+    oneOf:
+      - minItems: 1
+        items:
+          - const: mdp0-mem
+          - const: cpu-cfg
+
+      - minItems: 2
+        items:
+          - const: mdp0-mem
+          - const: mdp1-mem
+          - const: cpu-cfg
 
   resets:
     items:

Documentation/devicetree/bindings/display/msm/qcom,qcm2290-mdss.yaml

···
     maxItems: 2
 
   interconnects:
-    maxItems: 1
+    items:
+      - description: Interconnect path from mdp0 port to the data bus
+      - description: Interconnect path from CPU to the reg bus
 
   interconnect-names:
-    maxItems: 1
+    items:
+      - const: mdp0-mem
+      - const: cpu-cfg
 
 patternProperties:
   "^display-controller@[0-9a-f]+$":
···
         interrupt-controller;
         #interrupt-cells = <1>;
 
-        interconnects = <&mmrt_virt MASTER_MDP0 &bimc SLAVE_EBI1>;
-        interconnect-names = "mdp0-mem";
+        interconnects = <&mmrt_virt MASTER_MDP0 &bimc SLAVE_EBI1>,
+                        <&bimc MASTER_APPSS_PROC &config_noc SLAVE_DISPLAY_CFG>;
+        interconnect-names = "mdp0-mem",
+                             "cpu-cfg";
 
         iommus = <&apps_smmu 0x420 0x2>,
                  <&apps_smmu 0x421 0x0>;

Documentation/devicetree/bindings/display/msm/qcom,sc7180-mdss.yaml

···
     maxItems: 1
 
   interconnects:
-    maxItems: 1
+    items:
+      - description: Interconnect path from mdp0 port to the data bus
+      - description: Interconnect path from CPU to the reg bus
 
   interconnect-names:
-    maxItems: 1
+    items:
+      - const: mdp0-mem
+      - const: cpu-cfg
 
 patternProperties:
   "^display-controller@[0-9a-f]+$":
···
         interrupt-controller;
         #interrupt-cells = <1>;
 
-        interconnects = <&mmss_noc MASTER_MDP0 &mc_virt SLAVE_EBI1>;
-        interconnect-names = "mdp0-mem";
+        interconnects = <&mmss_noc MASTER_MDP0 &mc_virt SLAVE_EBI1>,
+                        <&gem_noc MASTER_APPSS_PROC &config_noc SLAVE_DISPLAY_CFG>;
+        interconnect-names = "mdp0-mem",
+                             "cpu-cfg";
 
         iommus = <&apps_smmu 0x800 0x2>;
         ranges;

Documentation/devicetree/bindings/display/msm/qcom,sc7280-mdss.yaml

···
     maxItems: 1
 
   interconnects:
-    maxItems: 1
+    items:
+      - description: Interconnect path from mdp0 port to the data bus
+      - description: Interconnect path from CPU to the reg bus
 
   interconnect-names:
-    maxItems: 1
+    items:
+      - const: mdp0-mem
+      - const: cpu-cfg
 
 patternProperties:
   "^display-controller@[0-9a-f]+$":
···
         interrupt-controller;
         #interrupt-cells = <1>;
 
-        interconnects = <&mmss_noc MASTER_MDP0 &mc_virt SLAVE_EBI1>;
-        interconnect-names = "mdp0-mem";
+        interconnects = <&mmss_noc MASTER_MDP0 &mc_virt SLAVE_EBI1>,
+                        <&gem_noc MASTER_APPSS_PROC &cnoc2 SLAVE_DISPLAY_CFG>;
+        interconnect-names = "mdp0-mem",
+                             "cpu-cfg";
 
         iommus = <&apps_smmu 0x900 0x402>;
         ranges;

Documentation/devicetree/bindings/display/msm/qcom,sm6115-mdss.yaml

···
   iommus:
     maxItems: 2
 
+  interconnects:
+    items:
+      - description: Interconnect path from mdp0 port to the data bus
+      - description: Interconnect path from CPU to the reg bus
+
+  interconnect-names:
+    items:
+      - const: mdp0-mem
+      - const: cpu-cfg
+
 patternProperties:
   "^display-controller@[0-9a-f]+$":
     type: object

Documentation/devicetree/bindings/display/msm/qcom,sm6125-mdss.yaml

···
     maxItems: 1
 
   interconnects:
-    maxItems: 2
+    items:
+      - description: Interconnect path from mdp0 port to the data bus
+      - description: Interconnect path from CPU to the reg bus
 
   interconnect-names:
-    maxItems: 2
+    items:
+      - const: mdp0-mem
+      - const: cpu-cfg
 
 patternProperties:
   "^display-controller@[0-9a-f]+$":

Documentation/devicetree/bindings/display/msm/qcom,sm6350-mdss.yaml

···
     maxItems: 1
 
   interconnects:
-    maxItems: 2
+    items:
+      - description: Interconnect path from mdp0 port to the data bus
+      - description: Interconnect path from CPU to the reg bus
 
   interconnect-names:
-    maxItems: 2
+    items:
+      - const: mdp0-mem
+      - const: cpu-cfg
 
 patternProperties:
   "^display-controller@[0-9a-f]+$":

Documentation/devicetree/bindings/display/msm/qcom,sm6375-mdss.yaml

···
     maxItems: 1
 
   interconnects:
-    maxItems: 2
+    items:
+      - description: Interconnect path from mdp0 port to the data bus
+      - description: Interconnect path from CPU to the reg bus
 
   interconnect-names:
-    maxItems: 2
+    items:
+      - const: mdp0-mem
+      - const: cpu-cfg
 
 patternProperties:
   "^display-controller@[0-9a-f]+$":

Documentation/devicetree/bindings/display/msm/qcom,sm8450-mdss.yaml

···
     maxItems: 1
 
   interconnects:
-    maxItems: 2
+    maxItems: 3
 
   interconnect-names:
-    maxItems: 2
+    maxItems: 3
 
 patternProperties:
   "^display-controller@[0-9a-f]+$":
···
         reg = <0x0ae00000 0x1000>;
         reg-names = "mdss";
 
-        interconnects = <&mmss_noc MASTER_MDP_DISP 0 &mc_virt SLAVE_EBI1_DISP 0>,
-                        <&mmss_noc MASTER_MDP_DISP 0 &mc_virt SLAVE_EBI1_DISP 0>;
-        interconnect-names = "mdp0-mem", "mdp1-mem";
+        interconnects = <&mmss_noc MASTER_MDP_DISP &mc_virt SLAVE_EBI1_DISP>,
+                        <&mmss_noc MASTER_MDP_DISP &mc_virt SLAVE_EBI1_DISP>,
+                        <&gem_noc MASTER_APPSS_PROC &config_noc SLAVE_DISPLAY_CFG>;
+        interconnect-names = "mdp0-mem",
+                             "mdp1-mem",
+                             "cpu-cfg";
 
         resets = <&dispcc DISP_CC_MDSS_CORE_BCR>;