On Wed, Jun 22, 2022 at 01:22:15PM +0200, Andrew Lunn wrote:

quoted

quoted

It's not device on MDIO bus, but the MDIO controller's register itself
(this _CSR belongs to the parent, subnodes do not refer to it in any
way). The child device requires only _ADR (or whatever else is needed
for the case the DSA device is attached to SPI/I2C controllers).

More and more the idea of standardizing the MDIOSerialBus() resource looks
plausible. The _ADR() usage is a bit grey area in ACPI specification. Maybe
someone can also make it descriptive, so Microsoft and others won't utilize
_ADR() in any level of weirdness.

I don't know if it makes any difference, but there are two protocols
spoken over MDIO, c22 and c45, specified in clause 22 and clause 45 of
the 802.3 specification. In some conditions, you need to specify which
protocol to speak to a device at a particular address. In DT we
indicate this with the compatible string, when maybe it should really
be considered as an extension of the address.

If somebody does produce a draft for MDIOSerialBus() i'm happy to
review it.

I also can review it. Marcin, would it be hard for you to prepare a formal
proposal for ACPI specification?

-- 
With Best Regards,
Andy Shevchenko