Re: [PATCH] net: usb: lan78xx: scan all MDIO addresses on LAN7801

[Martin Pålsson]

Hi Andrew.

Thank you for reviewing.

As for the PHY interface mode: the RGMII configuration (including TX/RX 
clock internal delays) is set via the configuration EEPROM on the 
device, so PHY_INTERFACE_MODE_RGMII_ID as set by lan78xx_get_phy() is 
correct for this hardware. The DP83TC814 supports RGMII and the link 
works well as-is, so no change is needed there.

I will resend with the Fixes: tag added.


Best regards

Martin


On 2/16/26 3:54 AM, Andrew Lunn wrote:
> On Sat, Feb 14, 2026 at 12:15:21PM +0000, Martin Pålsson wrote:
> > The LAN7801 is designed exclusively for external PHYs (unlike the
> > LAN7800/LAN7850 which have internal PHYs), but lan78xx_mdio_init()
> > restricts PHY scanning to MDIO addresses 0-7 by setting phy_mask to
> > ~(0xFF). This prevents discovery of external PHYs wired to addresses
> > outside that range.
> >
> > One such case is the DP83TC814 100BASE-T1 PHY, which is typically
> > configured at MDIO address 10 via PHYAD bootstrap pins and goes
> > undetected with the current mask.
> >
> > Set phy_mask to 0 for the LAN7801 so that all 32 MDIO addresses are
> > scanned during bus registration, allowing any external PHY to be
> > discovered regardless of its address.
> >
> > Signed-off-by: Martin Pålsson <martin@xxxxxxxxxxxx>
> Since you are submitting this for net, it should have a Fixes: tag.
>
> Also, since this is a 100Base PHY, i assume dev->interface needs to be
> PHY_INTERFACE_MODE_MII? But it looks like lan78xx_get_phy() is hard
> coding it to PHY_INTERFACE_MODE_RGMII_ID for the 7801. How is this
> working out for you?
>
> 	Andrew

--
Best regards / Bästa hälsningar / Mit freundlichen Grüßen

Martin Pålsson
Poleshift AB - Local Automotive Ethernet Solutions
+46 706 26 49 90
martin@xxxxxxxxxxxx