Re: [PATCH net-next 2/2] net: sfp: manage receiver and transmitter regulators

[Mark Brown]

On Tue, Mar 03, 2026 at 03:25:35PM +0000, Russell King (Oracle) wrote:
> On Tue, Mar 03, 2026 at 03:14:02PM +0000, Mark Brown wrote:

> > Sorry, what's the breakage here?  The log messages, or something else?

> ... which then caused someone to "fix" DT by disabling devices to shut
> up those log messages, including for platforms where those devices were
> being used, which ultimately caused a boot failure.

> ... and your argument that SATA PHYs need these supplies, which is false
> when the SATA PHY is integrated into the SoC and there's no details on
> what those supplies are or where they come from, or even if they are
> controllable.

The supplies don't need to be controllable or have any other information
to be specified, it sounds like this hardware has a fixed voltage
regulator that's supplying the PHY which is representable without any
changes, though I do agree it's annoying.

Though having said that with your description above I'm really not clear
that the regulator support is in the right place in the SATA framework
at all, it sounds like the supplies are being requested by the SATA
controller but the expectation is that the SATA controller is the thing
that is supplying power rather than consuming it.  I think that's where
things are going wrong here?  There are some SATA implementations that
don't include the power delivery part of SATA and only those require the
supplies?  The logs you posted looked like it was controllers requesting
the supplies which does look like the bindings and associated requests
aren't what I'd expect for something describing the hardware.

For SFP my understanding is that SFP has a physical specification which
includes power inputs and that these supplies are being requested by the
devices that consume them.  If some part of that is not the case then it
sounds like the bindings aren't describing the hardware (or at least are
a bit unclear about how they're doing so) and should be revised.  The
series doesn't seem to do anything at all with the supply side either,
I'm guessing there are some SFP controllers with integrated power
provisioning.

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