[PATCH RFC v2 1/5] dt-bindings: net: dwmac-meson: use picoseconds for the RGMII RX delay

From: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
To: davem@davemloft.net, kuba@kernel.org,
	linux-amlogic@lists.infradead.org, devicetree@vger.kernel.org,
	robh+dt@kernel.org, netdev@vger.kernel.org
Cc: jianxin.pan@amlogic.com, linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, khilman@baylibre.com,
	narmstrong@baylibre.com, jbrunet@baylibre.com, andrew@lunn.ch,
	f.fainelli@gmail.com,
	Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Subject: [PATCH RFC v2 1/5] dt-bindings: net: dwmac-meson: use picoseconds for the RGMII RX delay
Date: Sun, 15 Nov 2020 19:52:06 +0100	[thread overview]
Message-ID: <20201115185210.573739-2-martin.blumenstingl@googlemail.com> (raw)
In-Reply-To: <20201115185210.573739-1-martin.blumenstingl@googlemail.com>

Amlogic Meson G12A, G12B and SM1 SoCs have a more advanced RGMII RX
delay register which allows picoseconds precision. Deprecate the old
"amlogic,rx-delay-ns" in favour of a new "amlogic,rgmii-rx-delay-ps"
property.

For older SoCs the only known supported values were 0ns and 2ns. The new
SoCs have 200ps precision and support RGMII RX delays between 0ps and
3000ps.

While here, also update the description of the RX delay to indicate
that:
- with "rgmii" or "rgmii-id" the RX delay should be specified
- with "rgmii-id" or "rgmii-rxid" the RX delay is added by the PHY so
  any configuration on the MAC side is ignored
- with "rmii" the RX delay is not applicable and any configuration is
  ignored

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
---
 .../bindings/net/amlogic,meson-dwmac.yaml     | 61 +++++++++++++++++--
 1 file changed, 56 insertions(+), 5 deletions(-)

diff --git a/Documentation/devicetree/bindings/net/amlogic,meson-dwmac.yaml b/Documentation/devicetree/bindings/net/amlogic,meson-dwmac.yaml
index 6b057b117aa0..62a1e92a645c 100644
--- a/Documentation/devicetree/bindings/net/amlogic,meson-dwmac.yaml
+++ b/Documentation/devicetree/bindings/net/amlogic,meson-dwmac.yaml
@@ -74,17 +74,68 @@ allOf:
             Any configuration is ignored when the phy-mode is set to "rmii".
 
         amlogic,rx-delay-ns:
+          deprecated: true
           enum:
             - 0
             - 2
           default: 0
+          description:
+            The internal RGMII RX clock delay in nanoseconds. Deprecated, use
+            amlogic,rgmii-rx-delay-ps instead.
+
+        amlogic,rgmii-rx-delay-ps:
+          default: 0
           description:
             The internal RGMII RX clock delay (provided by this IP block) in
-            nanoseconds. When phy-mode is set to "rgmii" then the RX delay
-            should be explicitly configured. When the phy-mode is set to
-            either "rgmii-id" or "rgmii-rxid" the RX clock delay is already
-            provided by the PHY. Any configuration is ignored when the
-            phy-mode is set to "rmii".
+            picoseconds. When phy-mode is set to "rgmii" or "rgmii-id" then
+            the RX delay should be explicitly configured. When the phy-mode
+            is set to either "rgmii-id" or "rgmii-rxid" the RX clock delay
+            is already provided by the PHY so any configuration here is
+            ignored. Also any configuration is ignored when the phy-mode is
+            set to "rmii".
+
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - amlogic,meson8b-dwmac
+              - amlogic,meson8m2-dwmac
+              - amlogic,meson-gxbb-dwmac
+              - amlogic,meson-axg-dwmac
+    then:
+      properties:
+        amlogic,rgmii-rx-delay-ps:
+          enum:
+            - 0
+            - 2000
+
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - amlogic,meson-g12a-dwmac
+    then:
+      properties:
+        amlogic,rgmii-rx-delay-ps:
+          enum:
+            - 0
+            - 200
+            - 400
+            - 600
+            - 800
+            - 1000
+            - 1200
+            - 1400
+            - 1600
+            - 1800
+            - 2000
+            - 2200
+            - 2400
+            - 2600
+            - 2800
+            - 3000
 
 properties:
   compatible:
-- 
2.29.2

