net: stmmac: dwmac-qcom-ethqos: Respect phy-mode and TX delay

The driver currently sets a MAC TX delay of 2 ns no matter what the
phy-mode is. If the phy-mode indicates the phy is in charge of the
TX delay (rgmii-txid, rgmii-id), don't do it in the MAC.
Signed-off-by: Andrew Halaney <ahalaney@redhat.com>
Reviewed-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: Brian Masney <bmasney@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

drivers/net/ethernet/stmicro/stmmac/dwmac-qcom-ethqos.c

@@ -279,6 +279,17 @@ static int ethqos_dll_configure(struct qcom_ethqos *ethqos)
 
 static int ethqos_rgmii_macro_init(struct qcom_ethqos *ethqos)
 {
+	int phase_shift;
+	int phy_mode;
+
+	/* Determine if the PHY adds a 2 ns TX delay or the MAC handles it */
+	phy_mode = device_get_phy_mode(&ethqos->pdev->dev);
+	if (phy_mode == PHY_INTERFACE_MODE_RGMII_ID ||
+	    phy_mode == PHY_INTERFACE_MODE_RGMII_TXID)
+		phase_shift = 0;
+	else
+		phase_shift = RGMII_CONFIG2_TX_CLK_PHASE_SHIFT_EN;
+
 	/* Disable loopback mode */
 	rgmii_updatel(ethqos, RGMII_CONFIG2_TX_TO_RX_LOOPBACK_EN,
 		      0, RGMII_IO_MACRO_CONFIG2);
@@ -300,9 +311,9 @@ static int ethqos_rgmii_macro_init(struct qcom_ethqos *ethqos)
 			      RGMII_CONFIG_PROG_SWAP, RGMII_IO_MACRO_CONFIG);
 		rgmii_updatel(ethqos, RGMII_CONFIG2_DATA_DIVIDE_CLK_SEL,
 			      0, RGMII_IO_MACRO_CONFIG2);
+
 		rgmii_updatel(ethqos, RGMII_CONFIG2_TX_CLK_PHASE_SHIFT_EN,
-			      RGMII_CONFIG2_TX_CLK_PHASE_SHIFT_EN,
-			      RGMII_IO_MACRO_CONFIG2);
+			      phase_shift, RGMII_IO_MACRO_CONFIG2);
 		rgmii_updatel(ethqos, RGMII_CONFIG2_RSVD_CONFIG15,
 			      0, RGMII_IO_MACRO_CONFIG2);
 		rgmii_updatel(ethqos, RGMII_CONFIG2_RX_PROG_SWAP,
@@ -336,8 +347,7 @@ static int ethqos_rgmii_macro_init(struct qcom_ethqos *ethqos)
 		rgmii_updatel(ethqos, RGMII_CONFIG2_DATA_DIVIDE_CLK_SEL,
 			      0, RGMII_IO_MACRO_CONFIG2);
 		rgmii_updatel(ethqos, RGMII_CONFIG2_TX_CLK_PHASE_SHIFT_EN,
-			      RGMII_CONFIG2_TX_CLK_PHASE_SHIFT_EN,
-			      RGMII_IO_MACRO_CONFIG2);
+			      phase_shift, RGMII_IO_MACRO_CONFIG2);
 		rgmii_updatel(ethqos, RGMII_CONFIG_MAX_SPD_PRG_2,
 			      BIT(6), RGMII_IO_MACRO_CONFIG);
 		rgmii_updatel(ethqos, RGMII_CONFIG2_RSVD_CONFIG15,
@@ -375,7 +385,7 @@ static int ethqos_rgmii_macro_init(struct qcom_ethqos *ethqos)
 		rgmii_updatel(ethqos, RGMII_CONFIG2_DATA_DIVIDE_CLK_SEL,
 			      0, RGMII_IO_MACRO_CONFIG2);
 		rgmii_updatel(ethqos, RGMII_CONFIG2_TX_CLK_PHASE_SHIFT_EN,
-			      0, RGMII_IO_MACRO_CONFIG2);
+			      phase_shift, RGMII_IO_MACRO_CONFIG2);
 		rgmii_updatel(ethqos, RGMII_CONFIG_MAX_SPD_PRG_9,
 			      BIT(12) | GENMASK(9, 8),
 			      RGMII_IO_MACRO_CONFIG);