[PATCH net-next v16 06/15] net: phy: Create a phy_port for PHY-driven SFPs

[Christophe Leroy]

Reviewed-by: Christophe Leroy <christophe.leroy at csgroup.eu>



Le 13/11/2025 à 09:14, Maxime Chevallier a écrit :
> Some PHY devices may be used as media-converters to drive SFP ports (for
> example, to allow using SFP when the SoC can only output RGMII). This is
> already supported to some extend by allowing PHY drivers to registers
> themselves as being SFP upstream.
> 
> However, the logic to drive the SFP can actually be split to a per-port
> control logic, allowing support for multi-port PHYs, or PHYs that can
> either drive SFPs or Copper.
> 
> To that extent, create a phy_port when registering an SFP bus onto a
> PHY. This port is considered a "serdes" port, in that it can feed data
> to another entity on the link. The PHY driver needs to specify the
> various PHY_INTERFACE_MODE_XXX that this port supports.
> 
> Reviewed-by: Andrew Lunn <andrew at lunn.ch>
> Signed-off-by: Maxime Chevallier <maxime.chevallier at bootlin.com>
> ---
>   drivers/net/phy/phy_device.c | 24 ++++++++++++++++++++++++
>   drivers/net/phy/phy_port.c   | 14 ++++++++++++++
>   2 files changed, 38 insertions(+)
> 
> diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
> index f48565c3a9b8..3772c68b1dbc 100644
> --- a/drivers/net/phy/phy_device.c
> +++ b/drivers/net/phy/phy_device.c
> @@ -1643,6 +1643,26 @@ static void phy_del_port(struct phy_device *phydev, struct phy_port *port)
>   	phydev->n_ports--;
>   }
>   
> +static int phy_setup_sfp_port(struct phy_device *phydev)
> +{
> +	struct phy_port *port = phy_port_alloc();
> +
> +	if (!port)
> +		return -ENOMEM;
> +
> +	port->parent_type = PHY_PORT_PHY;
> +	port->phy = phydev;
> +
> +	/* The PHY is a media converter, the port connected to the SFP cage
> +	 * is a MII port.
> +	 */
> +	port->is_mii = true;
> +
> +	phy_add_port(phydev, port);
> +
> +	return 0;
> +}
> +
>   /**
>    * phy_sfp_probe - probe for a SFP cage attached to this PHY device
>    * @phydev: Pointer to phy_device
> @@ -1664,6 +1684,10 @@ int phy_sfp_probe(struct phy_device *phydev,
>   		ret = sfp_bus_add_upstream(bus, phydev, ops);
>   		sfp_bus_put(bus);
>   	}
> +
> +	if (phydev->sfp_bus)
> +		ret = phy_setup_sfp_port(phydev);
> +
>   	return ret;
>   }
>   EXPORT_SYMBOL(phy_sfp_probe);
> diff --git a/drivers/net/phy/phy_port.c b/drivers/net/phy/phy_port.c
> index 05455dc487cd..f89f70f83593 100644
> --- a/drivers/net/phy/phy_port.c
> +++ b/drivers/net/phy/phy_port.c
> @@ -132,6 +132,20 @@ void phy_port_update_supported(struct phy_port *port)
>   			port->pairs = max_t(int, port->pairs,
>   					    ethtool_linkmode_n_pairs(mode));
>   
> +	/* Serdes ports supported through SFP may not have any medium set,
> +	 * as they will output PHY_INTERFACE_MODE_XXX modes. In that case, derive
> +	 * the supported list based on these interfaces
> +	 */
> +	if (port->is_mii && linkmode_empty(supported)) {
> +		unsigned long interface, link_caps = 0;
> +
> +		/* Get each interface's caps */
> +		for_each_set_bit(interface, port->interfaces,
> +				 PHY_INTERFACE_MODE_MAX)
> +			link_caps |= phy_caps_from_interface(interface);
> +
> +		phy_caps_linkmodes(link_caps, port->supported);
> +	}
>   }
>   EXPORT_SYMBOL_GPL(phy_port_update_supported);
>