[PATCH v4 net-next] net: phy: mediatek: support MT7530 PHYs on EN71221 MCM

[Daniel Golle]

On Tue, Sep 15, 2026 at 10:35:50AM +0000, Caleb James DeLisle wrote:
> The EcoNet EN751221 multi-chip module implementation of the MT7530
> requires some additional configuration of the PHYs on startup.
> The reason for this is not known, but it is possible that it has
> to do with the fact that the EN751221 MCM implementation of the
> MT7530 runs at an abnormal PLL frequency (362.5Mhz).
> 
> Detect whether the MT7530 PHY is attached to the MDIO bus of an
> EcoNet EN751221 switch and if so, apply the necessary register
> updates. Additionally, never attempt to configure an MT7530
> identified PHY which does not have gigabit support because the same
> ID is used for another (FE) PHY.
> 
> Co-developed-by: Matheus Sampaio Queiroga <srherobrine20 at gmail.com>
> Signed-off-by: Matheus Sampaio Queiroga <srherobrine20 at gmail.com>
> Signed-off-by: Caleb James DeLisle <cjd at cjdns.fr>

> [...]
> +static bool en751221_is_mcm_phy(struct phy_device *phydev)
> +{
> +	struct device *parent = phydev->mdio.bus->parent;
> +
> +	return parent && parent->of_node &&
> +	       of_device_is_compatible(parent->of_node, "econet,en751221");

I thought you had found better options than using the parent of_node...?

> +}
> +
> +/*
> + * MTK_GPHY_ID_MT7530 ID is also used for an EcoNet SoC FE phy, but that PHY
> + * does not advertise ESTATUS_1000_TFULL.
> + */
> +static int mt7530_phy_match(struct phy_device *phydev,
> +			    const struct phy_driver *phydrv)
> +{

You miss the check for the PHY ID, see also below.

I'd suggest something like
	int ret;

	ret = genphy_match_phy_device(phydev, phydrv);
	if (!ret)
		return 0;

> +	return (phy_read(phydev, MII_ESTATUS) & ESTATUS_1000_TFULL) != 0 &&

The above should be helper function used by both .match_phy_device ops.

> +		!en751221_is_mcm_phy(phydev);
> +}
> +
> +static int en751221_phy_match(struct phy_device *phydev,
> +			      const struct phy_driver *phydrv)
> +{
> +	return (phy_read(phydev, MII_ESTATUS) & ESTATUS_1000_TFULL) != 0 &&
> +		en751221_is_mcm_phy(phydev);
> +}
> +
>  static int mt7531_phy_config_init(struct phy_device *phydev)
>  {
>  	mtk_gephy_config_init(phydev);
> @@ -135,6 +195,23 @@ static struct phy_driver mtk_gephy_driver[] = {
>  		 */
>  		.config_intr	= genphy_no_config_intr,
>  		.handle_interrupt = genphy_handle_interrupt_no_ack,
> +		.match_phy_device = mt7530_phy_match,
> +		.suspend	= genphy_suspend,
> +		.resume		= genphy_resume,
> +		.read_page	= mtk_phy_read_page,
> +		.write_page	= mtk_phy_write_page,
> +	},
> +	{
> +		PHY_ID_MATCH_EXACT(MTK_GPHY_ID_MT7530),

This assigns phy_id and phy_id_mask, which are used by
genphy_match_phy_device(). However, you are setting a .match_phy_device
op which doesn't call genphy_match_phy_device(), so this is ignored.

> +		.name		= "EcoNet EN751221 MCM PHY",
> +		.probe		= mt7530_phy_probe,
> +		.config_init	= en751221_mcm_phy_config_init,
> +		/* Interrupts are handled by the switch, not the PHY
> +		 * itself.
> +		 */
> +		.config_intr	= genphy_no_config_intr,
> +		.handle_interrupt = genphy_handle_interrupt_no_ack,
> +		.match_phy_device = en751221_phy_match,
>  		.suspend	= genphy_suspend,
>  		.resume		= genphy_resume,
>  		.read_page	= mtk_phy_read_page,
> -- 
> 2.39.5
>