Hi Russell,

On Tuesday, 3 March 2026 16:10:12 CET Russell King (Oracle) wrote:

On Tue, Mar 03, 2026 at 02:54:25PM +0100, Romain Gantois wrote:

quoted

Hi everyone,

This series describes regulators supplying the VccT and VccR pins of an
SFP
cage or soldered-down transceiver.

These regulators can then be turned on only when the SFP device is probed,
thus saving power on systems which only load SFP cage support at certain
times, or load SFP device descriptions via device tree overlays.

Please let me know what you think.

As ever, I don't want to be adding support for stuff into mainline
which doesn't ever get used - historically, we've had a lot of that.
So, any patch set which adds some kind of facility like this needs to
be accompanied by a user of it.

I understand, though I'm dealing with an out-of-tree board but I understand 
that this doesn't really count as a valid first use case.

This is especially true in this case, because I want to see why you're
wanting to have two regulators, when INF-8074 suggests that both VccT
and VccR should be derived from the same supply. The reason the
modules have separate supplies for the transmitter and receiver is
because the host side has the supply filtering networks to ensure
cross-talk between each is kept to a minimum.

Interesting, I wasn't aware of this. I thought it was something like "being 
able to shut down the transmitter side only while waiting for a WoL packet".

It seems like there won't be a v2 anyway but I just wanted to explain why I 
went with two regulators in the first place.

Thanks,

-- 
Romain Gantois, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com