Subject: [net-next v4 4/5] net: stmmac: starfive: Add jhb100 SGMII interface

From: Minda Chen <[email-masked]>
Date: Tue, 19 May 2026 18:14:35 +0800

Add jhb100 compatible and SGMII support. jhb100 soc contains
2 SGMII interfaces and integrated with serdes PHY. SGMII with
split TX/RX MAC clock and need to set 2.5M/25M/125M TX/RX clock
rate in 10M/100M/1000M speed mode.

Signed-off-by: Minda Chen <[email-masked]>
Reviewed-by: Sai Krishna <[email-masked]>
---
 .../ethernet/stmicro/stmmac/dwmac-starfive.c  | 58 ++++++++++++++-----
 1 file changed, 44 insertions(+), 14 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-starfive.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-starfive.c
index 16b955a6d77b..eb882ec14c8d 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-starfive.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-starfive.c
@@ -26,6 +26,7 @@ struct starfive_dwmac_data {
 struct starfive_dwmac {
 	struct device *dev;
 	const struct starfive_dwmac_data *data;
+	struct clk *sgmii_rx;
 };
 
 static int starfive_dwmac_set_mode(struct plat_stmmacenet_data *plat_dat)
@@ -68,6 +69,25 @@ static int starfive_dwmac_set_mode(struct plat_stmmacenet_data *plat_dat)
 	return 0;
 }
 
+static int stmmac_starfive_sgmii_set_clk_rate(void *bsp_priv, struct clk *clk_tx_i,
+					      phy_interface_t __maybe_unused interface,
+					      int speed)
+{
+	struct starfive_dwmac *dwmac = bsp_priv;
+	long rate = rgmii_clock(speed);
+	int ret;
+
+	/* MAC clock rate the same as RGMII */
+	if (rate < 0)
+		return 0;
+
+	ret = clk_set_rate(clk_tx_i, rate);
+	if (ret)
+		return ret;
+
+	return clk_set_rate(dwmac->sgmii_rx, rate);
+}
+
 static int starfive_dwmac_probe(struct platform_device *pdev)
 {
 	struct plat_stmmacenet_data *plat_dat;
@@ -102,23 +122,33 @@ static int starfive_dwmac_probe(struct platform_device *pdev)
 		return dev_err_probe(&pdev->dev, PTR_ERR(clk_gtx),
 				     "error getting gtx clock\n");
 
-	/* Generally, the rgmii_tx clock is provided by the internal clock,
-	 * which needs to match the corresponding clock frequency according
-	 * to different speeds. If the rgmii_tx clock is provided by the
-	 * external rgmii_rxin, there is no need to configure the clock
-	 * internally, because rgmii_rxin will be adaptively adjusted.
-	 */
-	if (!device_property_read_bool(&pdev->dev, "starfive,tx-use-rgmii-clk"))
-		plat_dat->set_clk_tx_rate = stmmac_set_clk_tx_rate;
-
 	dwmac->dev = &pdev->dev;
-	plat_dat->flags |= STMMAC_FLAG_EN_TX_LPI_CLK_PHY_CAP;
 	plat_dat->bsp_priv = dwmac;
-	plat_dat->dma_cfg->dche = true;
+	if (plat_dat->phy_interface == PHY_INTERFACE_MODE_SGMII) {
+		dwmac->sgmii_rx = devm_clk_get_enabled(&pdev->dev, "sgmii_rx");
+		if (IS_ERR(dwmac->sgmii_rx))
+			return dev_err_probe(&pdev->dev,
+					     PTR_ERR(dwmac->sgmii_rx),
+					     "error getting sgmii rx clock\n");
+		plat_dat->set_clk_tx_rate = stmmac_starfive_sgmii_set_clk_rate;
+	} else {
+		/*
+		 * Generally, the rgmii_tx clock is provided by the internal clock,
+		 * which needs to match the corresponding clock frequency according
+		 * to different speeds. If the rgmii_tx clock is provided by the
+		 * external rgmii_rxin, there is no need to configure the clock
+		 * internally, because rgmii_rxin will be adaptively adjusted.
+		 */
+		if (!device_property_read_bool(&pdev->dev, "starfive,tx-use-rgmii-clk"))
+			plat_dat->set_clk_tx_rate = stmmac_set_clk_tx_rate;
+
+		err = starfive_dwmac_set_mode(plat_dat);
+		if (err)
+			return err;
+	}
 
-	err = starfive_dwmac_set_mode(plat_dat);
-	if (err)
-		return err;
+	plat_dat->flags |= STMMAC_FLAG_EN_TX_LPI_CLK_PHY_CAP;
+	plat_dat->dma_cfg->dche = true;
 
 	return stmmac_dvr_probe(&pdev->dev, plat_dat, &stmmac_res);
 }
-- 
2.17.1