[PATCH net-next 02/10] net: stmmac: use phy_interface in stmmac_check_pcs_mode()

Russell King (Oracle)
2025-09-17T15:12:33Z

In the majority, if not all cases, mac_interface and phy_interface
are the same with the exception of some drivers that I have suggested
only use phy_interface and set mac_interface to PHY_INTERFACE_MODE_NA.

The only two that currently set mac_interface to PHY_INTERFACE_MODE_NA
are dwmac-loongson and dwmac-lpc18xx, neither of which use RGMII nor
SGMII.

In order to phase out the use of mac_interface, we need to have a path
for existing drivers so they can update to only using phy_interface
without causing regressions.

Therefore, in order to keep the "pcs" code working, we need to choose
the STMMAC integrated PCS mode based on phy_interface if mac_interface
is PHY_INTERFACE_MODE_NA.

This will allow more drivers to set mac_interface to
PHY_INTERFACE_MODE_NA without risking regressions.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
---
drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 8c8ca5999bd8..a23017a886f3 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -1120,6 +1120,9 @@ static void stmmac_check_pcs_mode(struct stmmac_priv *priv)
{
int interface = priv->plat->mac_interface;

+ if (interface == PHY_INTERFACE_MODE_NA)
+ interface = priv->plat->phy_interface;
+
if (priv->dma_cap.pcs) {
if ((interface == PHY_INTERFACE_MODE_RGMII) ||
(interface == PHY_INTERFACE_MODE_RGMII_ID) ||