Failed to reinit phy of spacemit-dwmac when reset-gpio is present

[Inochi Amaoto]

On Sun, Jul 12, 2026 at 10:55:51AM +0200, Maxime Chevallier wrote:
> Hi Inochi,
> 
> On 7/12/26 06:52, Inochi Amaoto wrote:
> > TL;DR:
> > 
> > The DWMAC on Spacemit K3 is failled to register phy after the reload
> > the driver module (rmmod then insmod). Because the reset-gpio is
> > asserted while unloading the driver and is not desserted before reading
> > the c22 id, which leads to a fault.
> 
> You're not the first one facing this type of issues, this is a long standing
> source of issues. The problem is partially hidden by the fact that often times
> the bootloader deals with the PHY reset (like the case you're facing)
> 
> Take a look at these discussions :
> 
> https://lore.kernel.org/netdev/cover.1761732347.git.buday.csaba@prolan.hu/
> 
> and maybe more intersting, Russell suggested an approach on how we could potentially
> address this here :
> 
> https://lore.kernel.org/all/aTBeVTlsElGXUCSN@shell.armlinux.org.uk/
> 
> 

Yeah, I have found these links, but it is something more than I want,
so I think I should deal with this carefully. I will have a try if I
have enough time, but currently I will send this workaround to dlan
to solve the problem....

Regards,
Inochi


> > ---
> > --- a/arch/riscv/boot/dts/spacemit/k3-pico-itx.dts
> > +++ b/arch/riscv/boot/dts/spacemit/k3-pico-itx.dts
> > @@ -196,7 +196,8 @@ &eth0 {
> > 
> >  	mdio {
> >  		phy0: phy at 1 {
> > -			compatible = "ethernet-phy-ieee802.3-c22";
> > +			compatible = "ethernet-phy-id001c.c916",
> > +				     "ethernet-phy-ieee802.3-c22";
> 
> Indeed that's merely a workaround :(
> 
> Maxime