[PATCH net-next v3 1/2] net: stmmac: Skip PHY attach if custom PCS is in use

[Zxyan Zhu <zxyan0222@gmail.com>]

When a platform provides a custom PCS via the pcs_init callback,
the MAC's phylink_pcs is already configured. In this case, no
traditional PHY device is needed.

Without this, stmmac_init_phy() falls through to the no-phy-node
path and errors out with "no phy found" when the DT has no
phy-handle for such interfaces.

Skip the PHY attach when priv->hw->phylink_pcs is set and
phy_addr is invalid.

Fixes: f0ef433fc264 ("net: stmmac: introduce pcs_init/pcs_exit stmmac operations")
Signed-off-by: Zxyan Zhu <zxyan0222@gmail.com>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 562d20830b94..575132b9cdbf 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -1347,6 +1347,10 @@ static int stmmac_init_phy(struct net_device *dev)
 		struct phy_device *phydev;
 
 		if (addr < 0) {
+			/* If a custom PCS is in use, no PHY is needed */
+			if (priv->hw->phylink_pcs)
+				return 0;
+
 			netdev_err(priv->dev, "no phy found\n");
 			return -ENODEV;
 		}
-- 
2.34.1