net: dsa: qca8k: Enable delay for RGMII_ID mode

[ Upstream commit a968b5e9 ]

RGMII_ID specifies that we should have internal delay, so resurrect the
delay addition routine but under the RGMII_ID mode.

Fixes: 40269aa9f40a ("net: dsa: qca8k: disable delay for RGMII mode")
Tested-by: Michal Vokáč <michal.vokac@ysoft.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/net/dsa/qca8k.c

@@ -451,6 +451,18 @@ qca8k_set_pad_ctrl(struct qca8k_priv *priv, int port, int mode)
 		qca8k_write(priv, QCA8K_REG_PORT5_PAD_CTRL,
 			    QCA8K_PORT_PAD_RGMII_RX_DELAY_EN);
 		break;
+	case PHY_INTERFACE_MODE_RGMII_ID:
+		/* RGMII_ID needs internal delay. This is enabled through
+		 * PORT5_PAD_CTRL for all ports, rather than individual port
+		 * registers
+		 */
+		qca8k_write(priv, reg,
+			    QCA8K_PORT_PAD_RGMII_EN |
+			    QCA8K_PORT_PAD_RGMII_TX_DELAY(QCA8K_MAX_DELAY) |
+			    QCA8K_PORT_PAD_RGMII_RX_DELAY(QCA8K_MAX_DELAY));
+		qca8k_write(priv, QCA8K_REG_PORT5_PAD_CTRL,
+			    QCA8K_PORT_PAD_RGMII_RX_DELAY_EN);
+		break;
 	case PHY_INTERFACE_MODE_SGMII:
 		qca8k_write(priv, reg, QCA8K_PORT_PAD_SGMII_EN);
 		break;

drivers/net/dsa/qca8k.h

@@ -40,6 +40,7 @@
 						((0x8 + (x & 0x3)) << 22)
 #define   QCA8K_PORT_PAD_RGMII_RX_DELAY(x)		\
 						((0x10 + (x & 0x3)) << 20)
+#define   QCA8K_MAX_DELAY				3
 #define   QCA8K_PORT_PAD_RGMII_RX_DELAY_EN		BIT(24)
 #define   QCA8K_PORT_PAD_SGMII_EN			BIT(7)
 #define QCA8K_REG_MODULE_EN				0x030