[net-next PATCH v4 01/15] Documentation: ACPI: DSD: Document MDIO PHY

[Calvin Johnson]

Hi Rafael,

Thanks for the review. I'll work on all the comments.

On Fri, Jan 22, 2021 at 08:22:21PM +0100, Rafael J. Wysocki wrote:
> On Fri, Jan 22, 2021 at 4:43 PM Calvin Johnson
> <calvin.johnson at oss.nxp.com> wrote:
> >
> > Introduce ACPI mechanism to get PHYs registered on a MDIO bus and
> > provide them to be connected to MAC.
> >
> > Describe properties "phy-handle" and "phy-mode".
> >
> > Signed-off-by: Calvin Johnson <calvin.johnson at oss.nxp.com>
> > ---
> >
> > Changes in v4:
> > - More cleanup
> 
> This looks much better that the previous versions IMV, some nits below.
> 
> > Changes in v3: None
> > Changes in v2:
> > - Updated with more description in document
> >
> >  Documentation/firmware-guide/acpi/dsd/phy.rst | 129 ++++++++++++++++++
> >  1 file changed, 129 insertions(+)
> >  create mode 100644 Documentation/firmware-guide/acpi/dsd/phy.rst
> >
> > diff --git a/Documentation/firmware-guide/acpi/dsd/phy.rst b/Documentation/firmware-guide/acpi/dsd/phy.rst
> > new file mode 100644
> > index 000000000000..76fca994bc99
> > --- /dev/null
> > +++ b/Documentation/firmware-guide/acpi/dsd/phy.rst
> > @@ -0,0 +1,129 @@
> > +.. SPDX-License-Identifier: GPL-2.0
> > +
> > +=========================
> > +MDIO bus and PHYs in ACPI
> > +=========================
> > +
> > +The PHYs on an MDIO bus [1] are probed and registered using
> > +fwnode_mdiobus_register_phy().
> 
> Empty line here, please.
> 
> > +Later, for connecting these PHYs to MAC, the PHYs registered on the
> > +MDIO bus have to be referenced.
> > +
> > +The UUID given below should be used as mentioned in the "Device Properties
> > +UUID For _DSD" [2] document.
> > +   - UUID: daffd814-6eba-4d8c-8a91-bc9bbf4aa301
> 
> I would drop the above paragraph.
> 
> > +
> > +This document introduces two _DSD properties that are to be used
> > +for PHYs on the MDIO bus.[3]
> 
> I'd say "for connecting PHYs on the MDIO bus [3] to the MAC layer."
> above and add the following here:
> 
> "These properties are defined in accordance with the "Device
> Properties UUID For _DSD" [2] document and the
> daffd814-6eba-4d8c-8a91-bc9bbf4aa301 UUID must be used in the Device
> Data Descriptors containing them."
> 
> > +
> > +phy-handle
> > +----------
> > +For each MAC node, a device property "phy-handle" is used to reference
> > +the PHY that is registered on an MDIO bus. This is mandatory for
> > +network interfaces that have PHYs connected to MAC via MDIO bus.
> > +
> > +During the MDIO bus driver initialization, PHYs on this bus are probed
> > +using the _ADR object as shown below and are registered on the MDIO bus.
> 
> Do you want to mention the "reg" property here?  I think it would be
> useful to do that.

No. I think we should adhere to _ADR in MDIO case. The "reg" property for ACPI
may be useful for other use cases that Andy is aware of.

Regards
Calvin