Re: [PATCH net-next 2/4] net: phy: motorcomm: Support YT8531S PHY in YT6801 Ethernet controller

[Yao Zi <ziyao@disroot.org>]

On Tue, Oct 14, 2025 at 06:08:35PM +0100, Russell King (Oracle) wrote:
> On Tue, Oct 14, 2025 at 04:47:45PM +0000, Yao Zi wrote:
> > YT6801's internal PHY is confirmed as a GMII-capable variant of YT8531S
> > by a previous series[1] and reading PHY ID. Add support for
> > PHY_INTERFACE_MODE_INTERNAL for YT8531S to allow the Ethernet driver to
> > reuse the PHY code for its internal PHY.
> 
> If it's known to be connected via a GMII interface, even if it's on the
> SoC, please use PHY_INTERFACE_MODE_GMII in preference to
> PHY_INTERFACE_MODE_INTERNAL. PHY_INTERFACE_MODE_INTERNAL is really for
> "we don't know what the internal interface is".

I use PHY_INTERFACE_MODE_INTERNAL for the driver based on Andrew's
feedback[1] on the series submitted by Motorcomm people,

> Is it really GMII? If so, add GMII to the yt8531 driver.
>
> Often this is described as PHY_INTERFACE_MODE_INTERNAL, meaning it
> does not matter what is being used between the MAC and the PHY, it is
> internal to the SoC. You might want to add that to the PHY driver.

Does PHY_INTERFACE_MODE_INTERNAL mean "unknown interface" or "interface
that doesn't matter"? I think this could lead to different choices for
the mode in YT6801's case.

Thanks for your answer,

Best regards,
Yao Zi

> Thanks.
> 
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[1]: https://lore.kernel.org/all/fde04f06-df39-41a8-8f74-036e315e9a8b@lunn.ch/