[RFC PATCH v2 3/7] dt-bindings: net: amlogic,meson-dwmac: add amlogic,t7-dwmac

[Lucas Tanure <tanure@linux.com>]

The T7 has the same ethernet glue as the G12A, but the controller
reaches memory through a pipeline stage that this SoC inserts in the
bus path. That stage has a gate of its own, which no other member of
the family has, and nothing else in Linux claims it. It is therefore
switched off as unused, and the port can then no longer finish a
transfer.

Describing it needs a fourth clock, and the fourth clock of the
existing list drives the timing adjustment logic, which the T7 never
uses. So the T7 gets a list of its own with the gate in that place,
under the name the SD and eMMC controllers already use.

Assisted-by: LLM
Signed-off-by: Lucas Tanure <tanure@linux.com>
---
 .../bindings/net/amlogic,meson-dwmac.yaml     | 47 +++++++++++++++++++
 1 file changed, 47 insertions(+)

diff --git a/Documentation/devicetree/bindings/net/amlogic,meson-dwmac.yaml b/Documentation/devicetree/bindings/net/amlogic,meson-dwmac.yaml
index 90ef79161ab1..96118b4d1560 100644
--- a/Documentation/devicetree/bindings/net/amlogic,meson-dwmac.yaml
+++ b/Documentation/devicetree/bindings/net/amlogic,meson-dwmac.yaml
@@ -23,6 +23,7 @@ select:
           - amlogic,meson-gxbb-dwmac
           - amlogic,meson-axg-dwmac
           - amlogic,meson-g12a-dwmac
+          - amlogic,t7-dwmac
   required:
     - compatible
 
@@ -57,6 +58,47 @@ allOf:
             - const: clkin1
             - const: timing-adjustment
 
+  # The T7 applies the RGMII RX delay through PRG_ETH1 and never enables the
+  # timing adjustment logic, so it has no timing-adjustment clock. What it does
+  # need is the gate of the pipeline stage the controller reaches DRAM through.
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: amlogic,t7-dwmac
+    then:
+      properties:
+        clocks:
+          items:
+            - description: GMAC main clock
+            - description: First parent clock of the internal mux
+            - description: Second parent clock of the internal mux
+            - description:
+                clock of the pipeline stage inserted in the bus path between
+                the controller and the DRAM. Without it, the controller cannot
+                complete DMA transfers.
+
+        clock-names:
+          items:
+            - const: stmmaceth
+            - const: clkin0
+            - const: clkin1
+            - const: pipeline
+
+  # Delay definitions for Meson8b and newer (including T7)
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - amlogic,meson8b-dwmac
+              - amlogic,meson8m2-dwmac
+              - amlogic,meson-gxbb-dwmac
+              - amlogic,meson-axg-dwmac
+              - amlogic,meson-g12a-dwmac
+              - amlogic,t7-dwmac
+    then:
+      properties:
         amlogic,tx-delay-ns:
           enum: [0, 2, 4, 6]
           default: 2
@@ -106,6 +148,7 @@ allOf:
           contains:
             enum:
               - amlogic,meson-g12a-dwmac
+              - amlogic,t7-dwmac
     then:
       properties:
         rx-internal-delay-ps:
@@ -143,6 +186,10 @@ properties:
               - amlogic,meson6-dwmac
               - amlogic,meson8m2-dwmac
           - const: snps,dwmac
+      - items:
+          - const: amlogic,t7-dwmac
+          - const: snps,dwmac-5.10a
+          - const: snps,dwmac
 
   reg:
     items:
-- 
2.56.0