[PATCH v6 1/2] dt-bindings: net: Add FSD EQoS device tree bindings
Swathi K S
swathi.ks at samsung.com
Mon Feb 17 19:55:08 PST 2025
> -----Original Message-----
> From: Andrew Lunn <andrew at lunn.ch>
> Sent: 17 February 2025 20:48
> To: Swathi K S <swathi.ks at samsung.com>
> Cc: krzk+dt at kernel.org; andrew+netdev at lunn.ch; davem at davemloft.net;
> edumazet at google.com; kuba at kernel.org; pabeni at redhat.com;
> robh at kernel.org; conor+dt at kernel.org; richardcochran at gmail.com;
> mcoquelin.stm32 at gmail.com; alexandre.torgue at foss.st.com;
> rmk+kernel at armlinux.org.uk; netdev at vger.kernel.org;
> devicetree at vger.kernel.org; linux-stm32 at st-md-mailman.stormreply.com;
> linux-arm-kernel at lists.infradead.org; linux-kernel at vger.kernel.org;
'Pankaj
> Dubey' <pankaj.dubey at samsung.com>; ravi.patel at samsung.com
> Subject: Re: [PATCH v6 1/2] dt-bindings: net: Add FSD EQoS device tree
> bindings
>
> > > > > > + phy-mode:
> > > > > > + enum:
> > > > > > + - rgmii-id
> > > > >
> > > > > phy-mode is normally a board property, in the .dts file, since
> > > > > the board
> > > > might
> > > > > decide to have extra long clock lines and so want 'rgmii'.
>
> > Hi Andrew,
> > What you said is right. Generally, PCB provides internal delay.
>
> It is actually pretty unusual for the PCB to add the delays. But there are
some
> boards which do this. Which is why you should support it.
>
> > But in this case, due to customer request, the delay was added into SoC.
>
> Idealy, by the PHY. However, in terms of DT, the board .dts file just
needs to
> say 'rmgii-id', meaning that the board does not provide the delays, so the
> MAC/PHY pair needs to provide the delay.
>
> > The following doc on rgmii says that "Devices which implement internal
> > delay shall be referred to as RGMII-ID.
> > Devices may offer an option to operate with/without internal delay and
> > still remain compliant with this spec"
> >
> https://community.nxp.com/pwmxy87654/attachments/pwmxy87654/imx-
> proces
> > sors/2
> > 0655/1/RGMIIv2_0_final_hp.pdf
> >
> > Also, the driver is in such a way that it handles all four rgmii in
> > the same way.
> >
> > Considering this, could you let us know what will be the right
> > approach to take in this case?
>
> List all four phy-modes in the binding. They should all be valid. However,
the
> .dtsi file should not list a phy-mode, since it is a board property, not a
SoC
> property.
Hi Andrew,
Thanks for the clarification.
Will post v7 with the following updates:
1. Changing phy-mode in dt-binding as shown below:
phy-mode:
enum:
- rgmii
- rgmii-id
- rgmii-rxid
- rgmii-txid
2. Removing phy-mode from .dtsi and example given in dt-binding
3. Add phy-mode to .dts file and specify 'rgmii-id' there.
Hope this will address your review comment.
Thanks,
Swathi
>
> Andrew
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