[PATCH v8 net-next 4/4] net: axiemac: use a phandle to reference pcs_phy

[Andy Chiu <andy.chiu@sifive.com>]

In some SGMII use cases where both a fixed link external PHY and the
internal PCS/PMA PHY need to be configured, we should explicitly use a
phandle "pcs-phy" to get the reference to the PCS/PMA PHY. Otherwise, the
driver would use "phy-handle" in the DT as the reference to both the
external and the internal PCS/PMA PHY.

In other cases where the core is connected to a SFP cage, we could still
point phy-handle to the intenal PCS/PMA PHY, and let the driver connect
to the SFP module, if exist, via phylink.

Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
Reviewed-by: Greentime Hu <greentime.hu@sifive.com>
Reviewed-by: Robert Hancock <robert.hancock@calian.com>
---
 drivers/net/ethernet/xilinx/xilinx_axienet_main.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
index 3daef64a85bd..d6fc3f7acdf0 100644
--- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
+++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
@@ -2071,9 +2071,16 @@ static int axienet_probe(struct platform_device *pdev)
 
 	if (lp->phy_mode == PHY_INTERFACE_MODE_SGMII ||
 	    lp->phy_mode == PHY_INTERFACE_MODE_1000BASEX) {
-		np = of_parse_phandle(pdev->dev.of_node, "phy-handle", 0);
+		np = of_parse_phandle(pdev->dev.of_node, "pcs-handle", 0);
 		if (!np) {
-			dev_err(&pdev->dev, "phy-handle required for 1000BaseX/SGMII\n");
+			/* Deprecated: Always use "pcs-handle" for pcs_phy.
+			 * Falling back to "phy-handle" here is only for
+			 * backward compatibility with old device trees.
+			 */
+			np = of_parse_phandle(pdev->dev.of_node, "phy-handle", 0);
+		}
+		if (!np) {
+			dev_err(&pdev->dev, "pcs-handle (preferred) or phy-handle required for 1000BaseX/SGMII\n");
 			ret = -EINVAL;
 			goto cleanup_mdio;
 		}
-- 
2.34.1