diff mbox series

net: dwc_eth_qos: Support external RMII reference clock on i.MX8M Plus

Message ID 20261030170618.2820085-1-dario.binacchi@amarulasolutions.com
State New
Headers
Series net: dwc_eth_qos: Support external RMII reference clock on i.MX8M Plus |

Commit Message

Dario Binacchi Oct. 30, 2026, 5:06 p.m. UTC 
In RMII mode the IOMUXC GPR[1] setup always selects the internally
generated reference clock, ignoring the snps,rmii_refclk_ext property.
On boards where the 50 MHz clock comes from an external source, the PHY
auto-negotiation times out:

    Waiting for PHY auto negotiation to complete...... TIMEOUT !
    phy_startup() failed: -110

Set ENET_QOS_CLK_TX_CLK_SEL only if snps,rmii_refclk_ext is missing, as
Linux does.

Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>

---

 arch/arm/mach-imx/imx8m/clock_imx8mm.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

---
base-commit: 3973f3c4d24df75ca90d7c0a9f03e5e5c9b48f32
branch: imx8mp-eqos-rmii-refclk-ext
diff mbox series

Patch

diff --git a/arch/arm/mach-imx/imx8m/clock_imx8mm.c b/arch/arm/mach-imx/imx8m/clock_imx8mm.c
index b7b3702041ee..065a946f2855 100644
--- a/arch/arm/mach-imx/imx8m/clock_imx8mm.c
+++ b/arch/arm/mach-imx/imx8m/clock_imx8mm.c
@@ -10,6 +10,7 @@ 
 #include <asm/arch/sys_proto.h>
 #include <asm/io.h>
 #include <div64.h>
+#include <dm/read.h>
 #include <errno.h>
 #include <linux/bitops.h>
 #include <linux/delay.h>
@@ -852,9 +853,11 @@  static int imx8mp_eqos_interface_init(struct udevice *dev,
 		break;
 	case PHY_INTERFACE_MODE_RMII:
 		setbits_le32(&gpr->gpr[1],
-			     IOMUXC_GPR_GPR1_GPR_ENET_QOS_CLK_TX_CLK_SEL |
 			     IOMUXC_GPR_GPR1_GPR_ENET_QOS_CLK_GEN_EN |
 			     IOMUXC_GPR_GPR1_GPR_ENET_QOS_INTF_SEL_RMII);
+		if (!dev_read_bool(dev, "snps,rmii_refclk_ext"))
+			setbits_le32(&gpr->gpr[1],
+				     IOMUXC_GPR_GPR1_GPR_ENET_QOS_CLK_TX_CLK_SEL);
 		break;
 	case PHY_INTERFACE_MODE_RGMII:
 	case PHY_INTERFACE_MODE_RGMII_ID: