[PATCH v4 2/7] dt-bindings: net: amlogic,meson-dwmac: add amlogic,t7-dwmac

[Lucas Tanure]

The T7 has the same ethernet glue as the G12A but needs two clocks of
its own. The controller reaches memory through a pipeline stage with
its own gate; nothing else claims it, so it is switched off as unused
and transfers never finish. The glue registers sit in a block clocked
together with the MDIO multiplexer, which probes after the controller
has programmed them: the writes are lost and the port keeps the
bootloader's delays.

So the T7 gets its own clock list, without the timing adjustment clock
it never uses. Its delays follow ethernet-controller.yaml: the PHY adds
the 2ns, and only the receive delay line offers fine tuning, so only
rx-internal-delay-ps is valid here.

Assisted-by: LLM
Signed-off-by: Lucas Tanure <tanure at linux.com>
---
 .../bindings/net/amlogic,meson-dwmac.yaml     | 60 +++++++++++++++++++
 1 file changed, 60 insertions(+)

diff --git a/Documentation/devicetree/bindings/net/amlogic,meson-dwmac.yaml b/Documentation/devicetree/bindings/net/amlogic,meson-dwmac.yaml
index 69244afc4ff8..d27f0f2c52b0 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 +58,61 @@ allOf:
             - const: clkin1
             - const: timing-adjustment
 
+  - 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.
+            - description:
+                clock of the register block holding PRG_ETH0 and PRG_ETH1.
+                Without it, the block reads as zero and ignores writes.
+
+        clock-names:
+          items:
+            - const: stmmaceth
+            - const: clkin0
+            - const: clkin1
+            - const: pipeline
+            - const: pclk
+
+        # The PHY adds the 2ns RGMII delays, see ethernet-controller.yaml.
+        # The RX delay line of this glue is fine tuning in 200ps steps,
+        # added on top of what phy-mode describes. The TX side has no fine
+        # tuning: its only step is a quarter of the clock period, the full
+        # 2ns at 1Gbit/s, so the TX property is not accepted.
+        tx-internal-delay-ps: false
+
+        rx-internal-delay-ps:
+          enum: [200, 400, 600, 800, 1000, 1200, 1400, 1600, 1800, 2000,
+                 2200, 2400, 2600, 2800, 3000]
+
+        amlogic,tx-delay-ns: false
+        amlogic,rx-delay-ns: false
+
+  # Delay definitions for Meson8b and newer
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - amlogic,meson8b-dwmac
+              - amlogic,meson8m2-dwmac
+              - amlogic,meson-gxbb-dwmac
+              - amlogic,meson-axg-dwmac
+              - amlogic,meson-g12a-dwmac
+    then:
+      properties:
         amlogic,tx-delay-ns:
           enum: [0, 2, 4, 6]
           default: 2
@@ -142,6 +198,10 @@ properties:
       - items:
           - const: amlogic,meson6-dwmac
           - const: snps,dwmac
+      - items:
+          - const: amlogic,t7-dwmac
+          - const: snps,dwmac-5.10a
+          - const: snps,dwmac
 
   reg:
     items:
-- 
2.56.0