Re: [PATCH v1] net: phy: tja11xx: add TJA1102 support

[Andrew Lunn <andrew@lunn.ch>]

Hi Oleksij

> TJA1102 is an dual T1 PHY chip. Both PHYs are separately addressable.
> PHY 0 can be identified by PHY ID. PHY 1 has no PHY ID and can be
> configured in device tree by setting compatible =
> "ethernet-phy-id0180.dc81".

Why-o-why do silicon vendors make devices with invalid PHY IDs!?!?!

Did you try avoiding the compatible string. We know PHY 0 will probe
as normal. From its PHY ID we know it is a dual device. Could the
probe of PHY 0 register PHY 1?

No idea if it will work, but could nxp-tja11xx.c register is fixup for
PHY_ID_TJA1102. That fixup would do something like:

void tja1102_fixup(struct phy_device *phydev_phy0)
{
        struct mii_bus *bus = phydev_phy0->mdio.mii;
        struct phy_device *phydev_phy1;

        phydev_phy1 = phy_device_create(bus, phydev_phy0->addr + 1,
                                        PHY_ID_TJA1102, FALSE, NULL);
	if (phydev_phy1)
               phy_device_register(phydev_phy1);
}

I think the issue here is, it will deadlock when scanning for fixup
for phydev_phy1. So this basic idea, but maybe hooked in somewhere
else?

Something like this might also help vsc8584 which is a quad PHY with
some shared registers?

	  Andrew