[PATCH 2/2] net: designware-imx: i.MX93: set TX_CLK in RMII mode

[Steffen Trumtrar]

According to NXP AT14149 the TX_CLK direction must be set to output
when the ENET is used in RMII mode.

Signed-off-by: Steffen Trumtrar <s.trumtrar at pengutronix.de>
---
 drivers/net/designware_imx.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/net/designware_imx.c b/drivers/net/designware_imx.c
index ab60d98298..2cc707ecac 100644
--- a/drivers/net/designware_imx.c
+++ b/drivers/net/designware_imx.c
@@ -26,6 +26,10 @@
 
 #define RMII_RESET_SPEED			(0x3 << 14)
 
+#define MX93_GPR_ENET_CLK_SEL_OFFSET		0x4
+#define MX93_ENET_CLK_ENET_QOS_TX_CLK_SEL_MASK	GENMASK(0, 0)
+#define MX93_ENET_CLK_ENET_QOS_TX_CLK_SEL	(0x1 << 0)
+
 struct eqos_imx_soc_data {
 	int (*set_interface_mode)(struct eqos *eqos);
 	void (*fix_soc_reset)(struct eqos *eqos, u32 *mac_regs);
@@ -155,6 +159,14 @@ static int eqos_imx93_set_interface_mode(struct eqos *eqos)
 		break;
 	case PHY_INTERFACE_MODE_RMII:
 		val = MX93_GPR_ENET_QOS_INTF_SEL_RMII;
+
+		/* According to NXP AN14149, the direction of the
+		 * TX_CLK must be set to output in RMII mode.
+		 */
+		regmap_update_bits(priv->intf_regmap,
+				   priv->intf_reg_off + MX93_GPR_ENET_CLK_SEL_OFFSET,
+				   MX93_ENET_CLK_ENET_QOS_TX_CLK_SEL_MASK,
+				   MX93_ENET_CLK_ENET_QOS_TX_CLK_SEL);
 		break;
 	case PHY_INTERFACE_MODE_RGMII:
 	case PHY_INTERFACE_MODE_RGMII_ID:

-- 
2.43.2