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

[Arnd Bergmann]

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