Re: [PATCH 2/2] ARM: dts: aspeed: ventura2: Add Meta ventura2 BMC

On Tue, Dec 23, 2025 at 6:35 PM Andrew Lunn [off-list ref] wrote:

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What make/model of switch is it? Is it unmanaged, or does it use SPI
or I2C for management?

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The switch is connected via RMII to the MAC and is managed over MDIO.

O.K. What make/model?

The device is a Marvell 88E6393X switch. In our design, the BMC connects
to the device via RMII with fixed link parameters to retrieve ethernet.

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On our board, MDIO is not wired directly to the processor; instead, we
use a USB-to-MPSSE bridge (FT2232) to toggle the MDIO signals for
switch management.

I have to push back on you using a closed source user space driver,
given that i help maintain the Ethernet switch drivers...

I know there have been attempts to get GPIO support added for FT2232,
but i don't think any got as far as mainline. That is probably the
only part you are missing. You can describe USB devices in DT. So you
should be able to describe such a GPIO controller. You can then
instantiate an virtual,mdio-gpio driver to give you an MDIO bus. And
then add nodes for the switch using DSA.

Apologies for the confusion in my previous reply.
The BMC connects to the peer via an RMII fixed-link.
The link parameters are fixed at design time and there is no runtime
MDIO-managed PHY or switch control from the BMC.

     Andrew