Subject: [PATCH RFC net-next+ 6/9] phy: qcom-sgmii-eth: use PHY interface mode for SerDes settings

From: "Russell King (Oracle)" <[email-masked]>
Date: Thu, 19 Feb 2026 12:50:54 +0000

As established in the previous commit, using SPEED_1000 and SPEED_2500
does not make sense for a SerDes due to the PCS encoding that is used
over the SerDes link, which inflates the data rate at the SerDes. Thus,
the use of these constants in a SerDes driver is incorrect.

Since qcom-sgmii-eth no longer implements phy_set_speed(), but instead
uses the PHY interface mode passed via the .set_mode() method, convert
the driver to use the PHY interface mode internally to decide whether
to configure the SerDes for 1.25Gbps or 3.125Gbps mode.

Signed-off-by: Russell King (Oracle) <[email-masked]>
---
 drivers/phy/qualcomm/phy-qcom-sgmii-eth.c | 41 ++++++++++++-----------
 1 file changed, 21 insertions(+), 20 deletions(-)

diff --git a/drivers/phy/qualcomm/phy-qcom-sgmii-eth.c b/drivers/phy/qualcomm/phy-qcom-sgmii-eth.c
index dcfdb7d0e8ea..58ff15601206 100644
--- a/drivers/phy/qualcomm/phy-qcom-sgmii-eth.c
+++ b/drivers/phy/qualcomm/phy-qcom-sgmii-eth.c
@@ -29,7 +29,7 @@
 struct qcom_dwmac_sgmii_phy_data {
 	struct regmap *regmap;
 	struct clk *refclk;
-	int speed;
+	phy_interface_t interface;
 };
 
 static void qcom_dwmac_sgmii_phy_init_1g(struct regmap *regmap)
@@ -223,15 +223,18 @@ static int qcom_dwmac_sgmii_phy_calibrate(struct phy *phy)
 	struct qcom_dwmac_sgmii_phy_data *data = phy_get_drvdata(phy);
 	struct device *dev = phy->dev.parent;
 
-	switch (data->speed) {
-	case SPEED_10:
-	case SPEED_100:
-	case SPEED_1000:
+	switch (data->interface) {
+	case PHY_INTERFACE_MODE_SGMII:
+	case PHY_INTERFACE_MODE_1000BASEX:
+		/* 1.25Gbps mode */
 		qcom_dwmac_sgmii_phy_init_1g(data->regmap);
 		break;
-	case SPEED_2500:
+	case PHY_INTERFACE_MODE_2500BASEX:
+		/* 3.125Gbps mode */
 		qcom_dwmac_sgmii_phy_init_2p5g(data->regmap);
 		break;
+	default:
+		return -EINVAL;
 	}
 
 	if (qcom_dwmac_sgmii_phy_poll_status(data->regmap,
@@ -287,17 +290,15 @@ static int qcom_dwmac_sgmii_phy_power_off(struct phy *phy)
 	return 0;
 }
 
-static int qcom_dwmac_sgmii_phy_speed(enum phy_mode mode, int submode)
+static int qcom_dwmac_sgmii_phy_interface(enum phy_mode mode, int submode)
 {
 	if (mode != PHY_MODE_ETHERNET)
 		return -EINVAL;
 
 	if (submode == PHY_INTERFACE_MODE_SGMII ||
-	    submode == PHY_INTERFACE_MODE_1000BASEX)
-		return SPEED_1000;
-
-	if (submode == PHY_INTERFACE_MODE_2500BASEX)
-		return SPEED_2500;
+	    submode == PHY_INTERFACE_MODE_1000BASEX ||
+	    submode == PHY_INTERFACE_MODE_2500BASEX)
+		return submode;
 
 	return -EINVAL;
 }
@@ -306,14 +307,14 @@ static int qcom_dwmac_sgmii_phy_set_mode(struct phy *phy, enum phy_mode mode,
 					 int submode)
 {
 	struct qcom_dwmac_sgmii_phy_data *data = phy_get_drvdata(phy);
-	int speed;
+	int interface;
 
-	speed = qcom_dwmac_sgmii_phy_speed(mode, submode);
-	if (speed < 0)
-		return speed;
+	interface = qcom_dwmac_sgmii_phy_interface(mode, submode);
+	if (interface < 0)
+		return interface;
 
-	if (speed != data->speed)
-		data->speed = speed;
+	if (interface != data->interface)
+		data->interface = interface;
 
 	return qcom_dwmac_sgmii_phy_calibrate(phy);
 }
@@ -322,7 +323,7 @@ static int qcom_dwmac_sgmii_phy_validate(struct phy *phy, enum phy_mode mode,
 					 int submode,
 					 union phy_configure_opts *opts)
 {
-	int ret = qcom_dwmac_sgmii_phy_speed(mode, submode);
+	int ret = qcom_dwmac_sgmii_phy_interface(mode, submode);
 
 	return ret < 0 ? ret : 0;
 }
@@ -356,7 +357,7 @@ static int qcom_dwmac_sgmii_phy_probe(struct platform_device *pdev)
 	if (!data)
 		return -ENOMEM;
 
-	data->speed = SPEED_10;
+	data->interface = PHY_INTERFACE_MODE_SGMII;
 
 	base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(base))
-- 
2.47.3