[PATCH] dt-bindings: net: dsa: mediatek,mt7530: improve binding description

From: arinc9 . unal
Date: Sun Feb 12 2023 - 08:13:43 EST


From: Arınç ÜNAL <arinc.unal@xxxxxxxxxx>

Fix inaccurate information about PHY muxing, and merge standalone and
multi-chip module MT7530 configuration methods.

Signed-off-by: Arınç ÜNAL <arinc.unal@xxxxxxxxxx>
---
.../bindings/net/dsa/mediatek,mt7530.yaml | 52 ++++++++-----------
1 file changed, 21 insertions(+), 31 deletions(-)

diff --git a/Documentation/devicetree/bindings/net/dsa/mediatek,mt7530.yaml b/Documentation/devicetree/bindings/net/dsa/mediatek,mt7530.yaml
index 08667bff74a5..449ee0735012 100644
--- a/Documentation/devicetree/bindings/net/dsa/mediatek,mt7530.yaml
+++ b/Documentation/devicetree/bindings/net/dsa/mediatek,mt7530.yaml
@@ -24,56 +24,46 @@ description: |

There is only the standalone version of MT7531.

- Port 5 on MT7530 has got various ways of configuration.
-
- For standalone MT7530:
+ Port 5 on MT7530 has got various ways of configuration:

- Port 5 can be used as a CPU port.

- - PHY 0 or 4 of the switch can be muxed to connect to the gmac of the SoC
- which port 5 is wired to. Usually used for connecting the wan port
- directly to the CPU to achieve 2 Gbps routing in total.
+ - PHY 0 or 4 of the switch can be muxed to gmac5 of the switch. Therefore,
+ the gmac of the SoC which is wired to port 5 can connect to the PHY.
+ This is usually used for connecting the wan port directly to the CPU to
+ achieve 2 Gbps routing in total.

- The driver looks up the reg on the ethernet-phy node which the phy-handle
- property refers to on the gmac node to mux the specified phy.
+ The driver looks up the reg on the ethernet-phy node, which the phy-handle
+ property on the gmac node refers to, to mux the specified phy.

The driver requires the gmac of the SoC to have "mediatek,eth-mac" as the
- compatible string and the reg must be 1. So, for now, only gmac1 of an
+ compatible string and the reg must be 1. So, for now, only gmac1 of a
MediaTek SoC can benefit this. Banana Pi BPI-R2 suits this.
- Check out example 5 for a similar configuration.
-
- - Port 5 can be wired to an external phy. Port 5 becomes a DSA slave.
- Check out example 7 for a similar configuration.
-
- For multi-chip module MT7530:
-
- - Port 5 can be used as a CPU port.
-
- - PHY 0 or 4 of the switch can be muxed to connect to gmac1 of the SoC.
- Usually used for connecting the wan port directly to the CPU to achieve 2
- Gbps routing in total.
-
- The driver looks up the reg on the ethernet-phy node which the phy-handle
- property refers to on the gmac node to mux the specified phy.

For the MT7621 SoCs, rgmii2 group must be claimed with rgmii2 function.
+
Check out example 5.

- - In case of an external phy wired to gmac1 of the SoC, port 5 must not be
- enabled.
+ - For the multi-chip module MT7530, in case of an external phy wired to
+ gmac1 of the SoC, port 5 must not be enabled.

In case of muxing PHY 0 or 4, the external phy must not be enabled.

For the MT7621 SoCs, rgmii2 group must be claimed with rgmii2 function.
+
Check out example 6.

- - Port 5 can be muxed to an external phy. Port 5 becomes a DSA slave.
- The external phy must be wired TX to TX to gmac1 of the SoC for this to
- work. Ubiquiti EdgeRouter X SFP is wired this way.
+ - Port 5 can be wired to an external phy. Port 5 becomes a DSA slave.
+
+ For the multi-chip module MT7530, the external phy must be wired TX to TX
+ to gmac1 of the SoC for this to work. Ubiquiti EdgeRouter X SFP is wired
+ this way.

- Muxing PHY 0 or 4 won't work when the external phy is connected TX to TX.
+ For the multi-chip module MT7530, muxing PHY 0 or 4 won't work when the
+ external phy is connected TX to TX.

For the MT7621 SoCs, rgmii2 group must be claimed with gpio function.
+
Check out example 7.

properties:
@@ -601,7 +591,7 @@ examples:
label = "lan4";
};

- /* Commented out, phy4 is muxed to gmac1.
+ /* Commented out, phy4 is connected to gmac1.
port@4 {
reg = <4>;
label = "wan";
--
2.37.2