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

[Rob Herring <robh@kernel.org>]

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@arinc9.com>
> ---
>  .../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@mediatek.com>
>  
>  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 //

> +  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.

> +
> +  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
> 
>