Re: [net-next: PATCH 09/12] Documentation: ACPI: DSD: introduce DSA description

[Marcin Wojtas]

pon., 20 cze 2022 o 20:19 Andrew Lunn <andrew@xxxxxxx> napisał(a):
>
> On Mon, Jun 20, 2022 at 05:02:22PM +0200, Marcin Wojtas wrote:
> > Describe the Distributed Switch Architecture (DSA) - compliant
> > MDIO devices. In ACPI world they are represented as children
> > of the MDIO busses, which are responsible for their enumeration
> > based on the standard _ADR fields and description in _DSD objects
> > under device properties UUID [1].
>
> I would say this is too limiting. In the DT world, they are not
> limited to MDIO children. They can be I2C children, SPI children
> etc. There are plenty of I2C switches and SPI switches. This is
> actually something we got wrong with the first DT binding. We simply
> translated the platform data in DT, and at that time, there was only
> MDIO switches supported. That was a real blocker to I2C, SPI and MMIO
> devices until we discarded the DT binding and had a second go.
>
> DSA switches are just devices on a bus, any sort of bus.
>
> Look at Documentation/devicetree/binding/net/dsa/dsa.yaml. There is no
> reference to MDIO.
>
> I would expect the same with ACPI. Somehow the bus enumerates and
> instantiates a device on the bus. The device then registers itself
> with the DSA core. The DSA core does not care what sort of bus it is
> on, that is the drivers problem.
>

Thanks for mentioning the other options. It makes things easier and
the MDIO as current strict dependency will be dropped.

Best regards,
Marcin