[PATCH net-next v19 06/15] net: phy: Create a phy_port for PHY-driven SFPs
From: Maxime Chevallier <maxime.chevallier@bootlin.com>
Date: 2025-11-22 12:43:49
Also in:
linux-arm-kernel, linux-arm-msm, linux-devicetree, lkml
Subsystem:
ethernet phy library, networking drivers, networking [ethtool phy port], the rest · Maintainers:
Andrew Lunn, Heiner Kallweit, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Maxime Chevallier, Linus Torvalds
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@lunn.ch> Reviewed-by: Christophe Leroy <redacted> Tested-by: Christophe Leroy <redacted> Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com> --- drivers/net/phy/phy_device.c | 24 ++++++++++++++++++++++++ drivers/net/phy/phy_port.c | 15 +++++++++++++++ 2 files changed, 39 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 0502fe60da3e..f89f70f83593 100644
--- a/drivers/net/phy/phy_port.c
+++ b/drivers/net/phy/phy_port.c@@ -131,6 +131,21 @@ void phy_port_update_supported(struct phy_port *port) __ETHTOOL_LINK_MODE_MASK_NBITS) 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);
--
2.49.0