net: dwmac-imx: add imx93 clock input support in RMII mode

If the rmii_refclk_ext boolean is set, configure the ENET QOS TX_CLK pin
direction to input. Otherwise, it defaults to output.

That mirrors what is already happening for the imx8mp in the
imx8mp_set_intf_mode function.

Signed-off-by: Mathieu Othacehe <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

drivers/net/ethernet/stmicro/stmmac/dwmac-imx.c

@@ -36,6 +36,8 @@
 #define MX93_GPR_ENET_QOS_INTF_SEL_RMII		(0x4 << 1)
 #define MX93_GPR_ENET_QOS_INTF_SEL_RGMII	(0x1 << 1)
 #define MX93_GPR_ENET_QOS_CLK_GEN_EN		(0x1 << 0)
+#define MX93_GPR_ENET_QOS_CLK_SEL_MASK		BIT_MASK(0)
+#define MX93_GPR_CLK_SEL_OFFSET			(4)
 
 #define DMA_BUS_MODE			0x00001000
 #define DMA_BUS_MODE_SFT_RESET		(0x1 << 0)
@@ -108,13 +110,21 @@ imx8dxl_set_intf_mode(struct plat_stmmacenet_data *plat_dat)
 static int imx93_set_intf_mode(struct plat_stmmacenet_data *plat_dat)
 {
 	struct imx_priv_data *dwmac = plat_dat->bsp_priv;
-	int val;
+	int val, ret;
 
 	switch (plat_dat->mac_interface) {
 	case PHY_INTERFACE_MODE_MII:
 		val = MX93_GPR_ENET_QOS_INTF_SEL_MII;
 		break;
 	case PHY_INTERFACE_MODE_RMII:
+		if (dwmac->rmii_refclk_ext) {
+			ret = regmap_clear_bits(dwmac->intf_regmap,
+						dwmac->intf_reg_off +
+						MX93_GPR_CLK_SEL_OFFSET,
+						MX93_GPR_ENET_QOS_CLK_SEL_MASK);
+			if (ret)
+				return ret;
+		}
 		val = MX93_GPR_ENET_QOS_INTF_SEL_RMII;
 		break;
 	case PHY_INTERFACE_MODE_RGMII: