Re: [PATCH v2 1/2] net: phy: adin: enable configuration of the LP Termination Register

From: Andrew Lunn

Date: Tue Dec 23 2025 - 04:36:12 EST


> +static int adin_config_zptm100(struct phy_device *phydev)
> +{
> + struct device *dev = &phydev->mdio.dev;
> + int reg;
> + int rc;
> +
> + if (!(device_property_read_bool(dev, "adi,low-cmode-impedance")))
> + return 0;
> +
> + /* set to 0 to configure for lowest common-mode impedance */
> + rc = phy_write_mmd(phydev, MDIO_MMD_VEND1, ADIN1300_B_100_ZPTM_DIMRX, 0x0);
> + if (rc < 0)
> + return rc;
> +
> + reg = phy_read_mmd(phydev, MDIO_MMD_VEND1, ADIN1300_B_100_ZPTM_DIMRX);
> + if (reg < 0)
> + return reg;
> +
> + if (!(reg & ADIN1300_B_100_ZPTM_EN_DIMRX)) {
> + phydev_err(phydev, "Failed to set lowest common-mode impedance.\n");
> + return -EINVAL;
> + }

Under what condition do you think this could happen? Do you think
there are variants of the hardware which do not have this register?

Andrew