R: R: [PATCH 3/3] arm64: dts: marvell: Add Sophos XGS 107w NPU board

[Nicolò Giuliani - nicolo.giuliani6@studio.unibo.it]

Hi Andrew,

As promised, the measurement of a driver-only reset.

On a running board (Linux 6.18) I unbound and re-bound the mv88e6xxx driver with reset-gpios (CP GPIO2 pin 17) in the device tree, so the only reset before the probe was the one done by the driver, with no boot loader reset in front of it. The switch was detected again and probed with all its ports in about one second, well within what the driver waits. So the 88E6193X is not slower than the other devices, and I will not send a driver patch. What I wrote in v1 (two seconds) was wrong.

I still do not know why the probe timed out when I booted through kexec from the vendor Linux, where nothing had reset the switch before the driver. I could not reproduce that failure with a reset done by the driver. v2 has reset-gpios and no comment about a boot loader reset.

The other points of your review are addressed in v2: no LED expander node, no comment about the SFP EEPROM addresses. I will send v2 as a new thread after the 24 hours have passed.

Thanks,
Nicolo Giuliani

________________________________________
Da: Andrew Lunn <andrew@xxxxxxx>
Inviato: domenica 20 settembre 2026 17:14
A: Nicolò Giuliani - nicolo.giuliani6@xxxxxxxxxxxxxxx
Cc: Rob Herring; Krzysztof Kozlowski; Conor Dooley; Gregory Clement; Sebastian Hesselbarth; devicetree@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Oggetto: Re: R: [PATCH 3/3] arm64: dts: marvell: Add Sophos XGS 107w NPU board

On Sun, Sep 20, 2026 at 08:48:20AM +0000, Nicolò Giuliani - nicolo.giuliani6@xxxxxxxxxxxxxxx wrote:
> Hi Andrew,
>
> Thanks for the review.
>
> > The reset line of the switch (CP GPIO2 pin 17) is deliberately not given
> > to the mv88e6xxx driver as reset-gpios. The 88E6193X needs about two
> > seconds after a reset before it can be used, much longer than the driver
> > waits, so the probe would time out.
> >
> > The obvious question is, why is your 88E6193X special?
>
> I don't think it is.

So please fix the driver to accept that the 88E6193X is much slower
than any other Marvell device.


I saw the probe time out when I started the kernel with kexec from the vendor Linux, so nothing had reset the switch before the driver did. When the boot loader resets the switch first, which is how the board normally boots, probing with reset-gpios works on this board (Linux 6.18). I have not been able to test a driver-only reset yet, because the boot loader always resets the switch first, so I cannot say what made the difference. I have not checked whether an EEPROM is attached. v2 describes reset-gpios and drops the comment.
>
> > +&cp0_i2c0 {
> > [...]
> > +     gpio@20 {
> >
> > Which port?
>
> It is the LED expander of the eight RJ45 ports (two pins per port). Nothing uses it yet, so I dropped the node from v2. It can come back together with the LED nodes.

Doesn't the 88E6193X have LED controllers of its own? Why do you need
additional LEDs?

        Andrew