Re: [PATCH] w5100: restore GPIO-based link detection

[Arthur Crépin Leblond]

On Wed, Aug 05, 2026 at 12:46:14PM +0200, Arnd Bergmann wrote:
> On Wed, Aug 5, 2026, at 11:44, Arthur Crépin Leblond wrote:
> > On Wed, Aug 05, 2026 at 11:11:53AM +0200, Arnd Bergmann wrote:
> > You're right for the W5100 that would not make any sense during data
> > transfers it would trigger the interrupt. That's unreliable.
> >
> > I am using the W5500, and in the datasheet it says
> >
> >    Link LED
> >    This shows the Link status.
> >    Low: Link is established
> >    High: Link is not established
> >
> > I can confirm it is what is happening, I don't see any changes
> > of state during TX/RX.
>
> Ok, good. On the other hand, the W5500 also has a PHYCFG register
> that should tell you the link status without looking at the
> GPIO line, though it's not clear if the CON/DISCON interrupt
> fires on link state change in MACRAW mode.
>
> It probably makes sense to wire up link w5100_get_link() to
> the phy register for w5500 either way, as that works without
> connecting a GPIO. Then you can just describe the LINKLED
> signal as an optional interrupt in the DT binding to trigger
> checking the link state in that register.
>
>     Arnd

Seems to work, the PHYCFG[0] bit gets updated on link change.

Arthur