Re: [PATCH net-next v3 2/8] dt-bindings: net: Add SoC-e SWIP MDIO controller

[Andrew Lunn <andrew@lunn.ch>]

On Wed, Sep 30, 2026 at 07:13:35PM +0200, Vasilij Strassheim wrote:
> On Wed, 2026-09-30 at 17:14 +0200, Andrew Lunn wrote:
> > On Wed, Sep 30, 2026 at 04:00:56PM +0200, Vasilij Strassheim wrote:
> > > On Sat, 2026-09-26 at 00:55 +0200, Andrew Lunn wrote:
> > > > > The controller exposes separate register regions for transaction data
> > > > > and for the shared transaction control and external bus selector
> > > > > register.
> > > > 
> > > > > +examples:
> > > > > +  - |
> > > > > +    mdio@204 {
> > > > > +        compatible = "soce,swip-mdio-23-02";
> > > > > +        reg = <0x204 0xc>, <0x200 0x4>;
> > > > 
> > > > At least in the example, they are not separate?
> > > 
> > > Not separate regions but registers...
> > > I'm obviously bad at documenting things.
> > > 
> > > The current information in the commit message is misleading and
> > > irrelevant. Looking at the bot's feedback, it's at the same time not
> > > clear enough yet that the mdio controller part is mapped within the
> > > switch memory and can't be used separately from it.
> > > 
> > > I will update the commit message to something like this:
> > > Add a binding for the MDIO controller integrated into SoC-e SWIP
> > > Ethernet switch IP cores.
> > > The controller shares the memory of the synthesized switch IP core and
> > > cannot be used independently.
> > 
> > I think part of the issue is the compatible. That suggests it is a
> > separate device, with its own driver. But it is actually driven by the
> > switch driver.
> 
> I can't avoid the compatible right now. Somehow it is still a separate
> functionality. I hope the following example doesn't cause unnecessary
> confusion, but rather helps to understand the system better:
> 
> The relationship between the MDIO controller and the switch core is more
> like that of tools in a Swiss Army knife.
> There are a few standalone tools, such as the knife and the screwdriver.
> These can also be described on their own. But they only make sense when
> they are attached to the knife as a whole. As soon as one takes it
> apart, the individual tools can no longer be used effectively. At the
> same time, no one needs to worry about the screwdriver if they only need
> the knife.

Maybe consider an MFD.

You then do get independent devices.

Also, with the current structure, i'm not sure how the mdio-mux is
getting instantiated. You list it inside the switch node, so i don't
think i will get turned into a platform device and probed. An MFD
might helper, maybe.

There are other switches which are described as MFD, so it is not
unknown.

      Andrew