[PATCH net-next 2/2] net: lan743x: add support for RMII interface

From: Thangaraj Samynathan

Date: Fri Mar 27 2026 - 01:43:00 EST


Enable RMII interface in the lan743x driver for PHY and MAC
configuration.

- Select RMII interface in lan743x_phy_interface_select().
- Update phylink supported_interfaces and MAC capabilities.
- Enable RMII via RMII_CTL in lan743x_hardware_init().
- Define RMII_CTL register and enable bit in lan743x_main.h.

Signed-off-by: Thangaraj Samynathan <thangaraj.s@xxxxxxxxxxxxx>
---
drivers/net/ethernet/microchip/lan743x_main.c | 18 ++++++++++++++++++
drivers/net/ethernet/microchip/lan743x_main.h | 3 +++
2 files changed, 21 insertions(+)

diff --git a/drivers/net/ethernet/microchip/lan743x_main.c b/drivers/net/ethernet/microchip/lan743x_main.c
index b7b1584d867d..86d35810460f 100644
--- a/drivers/net/ethernet/microchip/lan743x_main.c
+++ b/drivers/net/ethernet/microchip/lan743x_main.c
@@ -1370,6 +1370,8 @@ static void lan743x_phy_interface_select(struct lan743x_adapter *adapter)

if (adapter->is_pci11x1x && adapter->is_sgmii_en)
adapter->phy_interface = PHY_INTERFACE_MODE_SGMII;
+ else if (adapter->is_pci11x1x && adapter->is_rmii_en)
+ adapter->phy_interface = PHY_INTERFACE_MODE_RMII;
else if (id_rev == ID_REV_ID_LAN7430_)
adapter->phy_interface = PHY_INTERFACE_MODE_GMII;
else if ((id_rev == ID_REV_ID_LAN7431_) && (data & MAC_CR_MII_EN_))
@@ -3158,6 +3160,13 @@ static int lan743x_phylink_create(struct lan743x_adapter *adapter)
__set_bit(PHY_INTERFACE_MODE_MII,
adapter->phylink_config.supported_interfaces);
break;
+ case PHY_INTERFACE_MODE_RMII:
+ __set_bit(PHY_INTERFACE_MODE_RMII,
+ adapter->phylink_config.supported_interfaces);
+ adapter->phylink_config.mac_capabilities &= ~MAC_1000FD;
+ adapter->phylink_config.lpi_capabilities = 0;
+ break;
+
default:
phy_interface_set_rgmii(adapter->phylink_config.supported_interfaces);
}
@@ -3165,6 +3174,9 @@ static int lan743x_phylink_create(struct lan743x_adapter *adapter)
memcpy(adapter->phylink_config.lpi_interfaces,
adapter->phylink_config.supported_interfaces,
sizeof(adapter->phylink_config.lpi_interfaces));
+ if (adapter->phy_interface == PHY_INTERFACE_MODE_RMII)
+ __clear_bit(PHY_INTERFACE_MODE_RMII,
+ adapter->phylink_config.lpi_interfaces);

pl = phylink_create(&adapter->phylink_config, NULL,
adapter->phy_interface, &lan743x_phylink_mac_ops);
@@ -3509,6 +3521,7 @@ static int lan743x_hardware_init(struct lan743x_adapter *adapter,
{
struct lan743x_tx *tx;
u32 sgmii_ctl;
+ u32 rmii_ctl;
int index;
int ret;

@@ -3530,6 +3543,11 @@ static int lan743x_hardware_init(struct lan743x_adapter *adapter,
sgmii_ctl |= SGMII_CTL_SGMII_POWER_DN_;
}
lan743x_csr_write(adapter, SGMII_CTL, sgmii_ctl);
+ if (adapter->is_rmii_en) {
+ rmii_ctl = lan743x_csr_read(adapter, RMII_CTL);
+ rmii_ctl |= RMII_CTL_RMII_ENABLE_;
+ lan743x_csr_write(adapter, RMII_CTL, rmii_ctl);
+ }
} else {
adapter->max_tx_channels = LAN743X_MAX_TX_CHANNELS;
adapter->used_tx_channels = LAN743X_USED_TX_CHANNELS;
diff --git a/drivers/net/ethernet/microchip/lan743x_main.h b/drivers/net/ethernet/microchip/lan743x_main.h
index 1d7d37456553..03f3727ed8f7 100644
--- a/drivers/net/ethernet/microchip/lan743x_main.h
+++ b/drivers/net/ethernet/microchip/lan743x_main.h
@@ -324,6 +324,9 @@
#define MAC_WUCSR2_IPV6_TCPSYN_RCD_ BIT(5)
#define MAC_WUCSR2_IPV4_TCPSYN_RCD_ BIT(4)

+#define RMII_CTL (0x710)
+#define RMII_CTL_RMII_ENABLE_ BIT(0)
+
#define SGMII_ACC (0x720)
#define SGMII_ACC_SGMII_BZY_ BIT(31)
#define SGMII_ACC_SGMII_WR_ BIT(30)
--
2.34.1