[PATCH 2/4] dt-bindings: net: dsa: document internal MDIO bus

[Arınç ÜNAL]

On 13.08.2023 22:01, Vladimir Oltean wrote:
> On Sun, Aug 13, 2023 at 03:59:11PM +0300, Arınç ÜNAL wrote:
>>> sja1105 does not support an "mdio" child property. I haven't checked the
>>> others. Don't add properties that aren't supported.
>>
>> Adding the mdio property to the dsa.yaml schema will allow it on all of the
>> schemas that refer to dsa.yaml such as this one. This addition here is only
>> to disallow additional properties under the mdio property for this specific
>> schema.
>>
>> That said, my understanding is that the internal MDIO bus exists on all of
>> the switches controlled by DSA.
> 
> How come?
> 
>> Whether each individual DSA subdriver supports registering it does not
>> matter in terms of documenting the internal MDIO bus for all DSA
>> switches.
>>
>> SJA1110 uses the mdios property instead because it's got two internal mdio
>> buses, which is why I invalidate the mdio property for it. If SJA1105 has
>> also got two internal mdio buses, let me know.
> 
> SJA1105 has zero internal MDIO buses and zero internal PHYs.

Ah okay. I didn't consider the switch architecture where the data interface
of the PHY is connected to the switch, and the PHY management interface is
connected to the mdio bus that the switch is connected to.

The schemas of the switches which already utilise the mdio property:
- /schemas/net/dsa/microchip,lan937x.yaml
- /schemas/net/dsa/qca8k.yaml
- /schemas/net/dsa/realtek.yaml
- /schemas/net/dsa/renesas,rzn1-a5psw.yaml

The schemas of the switches which don't have an internal MDIO bus, meaning
the mdio property must be invalid:
- /schemas/net/mscc,vsc7514-switch.yaml
- /schemas/net/dsa/nxp,sja1105.yaml

The schemas of the switches which I don't know if the switch has got an
internal MDIO bus:
- /schemas/net/dsa/arrow,xrs700x.yaml
   - I believe, because there's phy-handle defined on every port without the
     mdio node on the example, the PHYs are not connected to the internal
     MDIO bus. Therefore, we can invalidate the mdio property for this
     schema.
- /schemas/net/dsa/brcm,b53.yaml
   - Seems ok to keep it valid.
- /schemas/net/dsa/brcm,sf2.yaml
   - Seems ok to keep it valid.
- /schemas/net/dsa/hirschmann,hellcreek.yaml
   - Same as /schemas/net/dsa/arrow,xrs700x.yaml.
- /schemas/net/dsa/microchip,ksz.yaml
   - Seems ok to keep it valid.
- /schemas/net/dsa/mscc,ocelot.yaml
   - Same as /schemas/net/dsa/arrow,xrs700x.yaml.

Not json-schema documentation, don't care about:
- ar9331.txt
- lan9303.txt
- lantiq-gswip.txt
- marvell.txt
- vitesse,vsc73xx.txt

Arınç