Re: [PATCH v2 7/7] dt-bindings: net: dsa: mediatek,mt7530: update binding description

From: Arınç ÜNAL
Date: Tue Aug 16 2022 - 17:54:55 EST

On 17.08.2022 00:25, Rob Herring wrote:
On Sat, Aug 13, 2022 at 06:44:15PM +0300, Arınç ÜNAL wrote:
Update the description of the binding.

- Describe the switches, which SoCs they are in, or if they are standalone.
- Explain the various ways of configuring MT7530's port 5.
- Remove phy-mode = "rgmii-txid" from description. Same code path is
followed for delayed rgmii and rgmii phy-mode on mtk_eth_soc.c.

Signed-off-by: Arınç ÜNAL <arinc.unal@xxxxxxxxxx>
---
.../bindings/net/dsa/mediatek,mt7530.yaml | 97 ++++++++++++-------
1 file changed, 62 insertions(+), 35 deletions(-)

diff --git a/Documentation/devicetree/bindings/net/dsa/mediatek,mt7530.yaml b/Documentation/devicetree/bindings/net/dsa/mediatek,mt7530.yaml
index 530ef5a75a2f..cf6340d072df 100644
--- a/Documentation/devicetree/bindings/net/dsa/mediatek,mt7530.yaml
+++ b/Documentation/devicetree/bindings/net/dsa/mediatek,mt7530.yaml
@@ -13,41 +13,68 @@ maintainers:
- Sean Wang <sean.wang@xxxxxxxxxxxx>
description: |
- Port 5 of mt7530 and mt7621 switch is muxed between:
- 1. GMAC5: GMAC5 can interface with another external MAC or PHY.
- 2. PHY of port 0 or port 4: PHY interfaces with an external MAC like 2nd GMAC
- of the SOC. Used in many setups where port 0/4 becomes the WAN port.
- Note: On a MT7621 SOC with integrated switch: 2nd GMAC can only connected to
- GMAC5 when the gpios for RGMII2 (GPIO 22-33) are not used and not
- connected to external component!
-
- Port 5 modes/configurations:
- 1. Port 5 is disabled and isolated: An external phy can interface to the 2nd
- GMAC of the SOC.
- In the case of a build-in MT7530 switch, port 5 shares the RGMII bus with 2nd
- GMAC and an optional external phy. Mind the GPIO/pinctl settings of the SOC!
- 2. Port 5 is muxed to PHY of port 0/4: Port 0/4 interfaces with 2nd GMAC.
- It is a simple MAC to PHY interface, port 5 needs to be setup for xMII mode
- and RGMII delay.
- 3. Port 5 is muxed to GMAC5 and can interface to an external phy.
- Port 5 becomes an extra switch port.
- Only works on platform where external phy TX<->RX lines are swapped.
- Like in the Ubiquiti ER-X-SFP.
- 4. Port 5 is muxed to GMAC5 and interfaces with the 2nd GAMC as 2nd CPU port.
- Currently a 2nd CPU port is not supported by DSA code.
-
- Depending on how the external PHY is wired:
- 1. normal: The PHY can only connect to 2nd GMAC but not to the switch
- 2. swapped: RGMII TX, RX are swapped; external phy interface with the switch as
- a ethernet port. But can't interface to the 2nd GMAC.
-
- Based on the DT the port 5 mode is configured.
-
- Driver tries to lookup the phy-handle of the 2nd GMAC of the master device.
- When phy-handle matches PHY of port 0 or 4 then port 5 set-up as mode 2.
- phy-mode must be set, see also example 2 below!
- * mt7621: phy-mode = "rgmii-txid";
- * mt7623: phy-mode = "rgmii";
+ There are two versions of MT7530, standalone and in a multi-chip module.
+
+ MT7530 is a part of the multi-chip module in MT7620AN, MT7620DA, MT7620DAN,
+ MT7620NN, MT7621AT, MT7621DAT, MT7621ST and MT7623AI SoCs.
+
+ MT7530 in MT7620AN, MT7620DA, MT7620DAN and MT7620NN SoCs has got 10/100 PHYs

s/got //

Can't use British English on bindings? :)


+ and the switch registers are directly mapped into SoC's memory map rather than
+ using MDIO. There is currently no support for this.

No support in the binding or driver? Driver capabilities are relevant to
the binding.

In the driver. Also, did you mean irrelevant? Should I remove this part from the binding?


+
+ There is only the standalone version of MT7531.
+
+ Port 5 on MT7530 has got various ways of configuration.

s/got //

+
+ For standalone MT7530:
+
+ - 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.
+
+ 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 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
+ 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.
+
+ 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.
+
+ 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:
compatible:
--
2.34.1