[PATCH net-next v13 14/18] net: phy: at803x: Support SFP through phy_port interface

Maxime Chevallier
2025-09-21T16:08:04Z

Convert the at803x driver to use the generic phylib SFP handling, via a
dedicated .attach_port() callback, populating the supported interfaces.

As these devices are limited to 1000BaseX, a workaround is used to also
support, in a very limited way, copper modules. This is done by
supporting SGMII but limiting it to 1G full duplex (in which case it's
somewhat compatible with 1000BaseX).

Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Tested-by: Oleksij Rempel <o.rempel@pengutronix.de>
Tested-by: Florian Fainelli <florian.fainelli@broadcom.com>
Tested-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
---
drivers/net/phy/qcom/at803x.c | 78 ++++++++++++++---------------------
1 file changed, 32 insertions(+), 46 deletions(-)

diff --git a/drivers/net/phy/qcom/at803x.c b/drivers/net/phy/qcom/at803x.c
index 51a132242462..2995b08bac96 100644
--- a/drivers/net/phy/qcom/at803x.c
+++ b/drivers/net/phy/qcom/at803x.c
@@ -20,7 +20,7 @@
#include <linux/of.h>
#include <linux/phylink.h>
#include <linux/reset.h>
-#include <linux/sfp.h>
+#include <linux/phy_port.h>
#include <dt-bindings/net/qca-ar803x.h>

#include "qcom.h"
@@ -769,58 +769,44 @@ static int at8031_register_regulators(struct phy_device *phydev)
return 0;
}

-static int at8031_sfp_insert(void *upstream, const struct sfp_eeprom_id *id)
+static int at803x_configure_mii(struct phy_port *port, bool enable,
+ phy_interface_t interface)
{
- struct phy_device *phydev = upstream;
- __ETHTOOL_DECLARE_LINK_MODE_MASK(phy_support);
- __ETHTOOL_DECLARE_LINK_MODE_MASK(sfp_support);
- DECLARE_PHY_INTERFACE_MASK(interfaces);
- phy_interface_t iface;
-
- linkmode_zero(phy_support);
- phylink_set(phy_support, 1000baseX_Full);
- phylink_set(phy_support, 1000baseT_Full);
- phylink_set(phy_support, Autoneg);
- phylink_set(phy_support, Pause);
- phylink_set(phy_support, Asym_Pause);
-
- linkmode_zero(sfp_support);
- sfp_parse_support(phydev->sfp_bus, id, sfp_support, interfaces);
- /* Some modules support 10G modes as well as others we support.
- * Mask out non-supported modes so the correct interface is picked.
- */
- linkmode_and(sfp_support, phy_support, sfp_support);
+ struct phy_device *phydev = port_phydev(port);

- if (linkmode_empty(sfp_support)) {
- dev_err(&phydev->mdio.dev, "incompatible SFP module inserted\n");
- return -EINVAL;
- }
+ if (interface == PHY_INTERFACE_MODE_SGMII)
+ dev_warn(&phydev->mdio.dev,
+ "module may not function if 1000Base-X not supported\n");
+
+ return 0;
+}

- iface = sfp_select_interface(phydev->sfp_bus, sfp_support);
+static const struct phy_port_ops at803x_port_ops = {
+ .configure_mii = at803x_configure_mii,
+};

- /* Only 1000Base-X is supported by AR8031/8033 as the downstream SerDes
- * interface for use with SFP modules.
- * However, some copper modules detected as having a preferred SGMII
- * interface do default to and function in 1000Base-X mode, so just
- * print a warning and allow such modules, as they may have some chance
- * of working.
+static int at8031_attach_mii_port(struct phy_device *phydev,
+ struct phy_port *port)
+{
+ linkmode_zero(port->supported);
+ phylink_set(port->supported, 1000baseX_Full);
+ phylink_set(port->supported, 1000baseT_Full);
+ phylink_set(port->supported, Autoneg);
+ phylink_set(port->supported, Pause);
+ phylink_set(port->supported, Asym_Pause);
+
+ /* This device doesn't really support SGMII. However, do our best
+ * to be compatible with copper modules (that usually require SGMII),
+ * in a degraded mode as we only allow 1000BaseT Full
*/
- if (iface == PHY_INTERFACE_MODE_SGMII)
- dev_warn(&phydev->mdio.dev, "module may not function if 1000Base-X not supported\n");
- else if (iface != PHY_INTERFACE_MODE_1000BASEX)
- return -EINVAL;
+ __set_bit(PHY_INTERFACE_MODE_SGMII, port->interfaces);
+ __set_bit(PHY_INTERFACE_MODE_1000BASEX, port->interfaces);
+
+ port->ops = &at803x_port_ops;

return 0;
}

-static const struct sfp_upstream_ops at8031_sfp_ops = {
- .attach = phy_sfp_attach,
- .detach = phy_sfp_detach,
- .module_insert = at8031_sfp_insert,
- .connect_phy = phy_sfp_connect_phy,
- .disconnect_phy = phy_sfp_disconnect_phy,
-};
-
static int at8031_parse_dt(struct phy_device *phydev)
{
struct device_node *node = phydev->mdio.dev.of_node;
@@ -841,8 +827,7 @@ static int at8031_parse_dt(struct phy_device *phydev)
return ret;
}

- /* Only AR8031/8033 support 1000Base-X for SFP modules */
- return phy_sfp_probe(phydev, &at8031_sfp_ops);
+ return 0;
}

static int at8031_probe(struct phy_device *phydev)
@@ -1173,6 +1158,7 @@ static struct phy_driver at803x_driver[] = {
.set_tunable = at803x_set_tunable,
.cable_test_start = at8031_cable_test_start,
.cable_test_get_status = at8031_cable_test_get_status,
+ .attach_mii_port = at8031_attach_mii_port,
}, {
/* Qualcomm Atheros AR8032 */
PHY_ID_MATCH_EXACT(ATH8032_PHY_ID),
--
2.49.0