[PATCH v4 12/12] arm64: dts: st: Add I/O sync to eth pinctrl in stm32mp25-pinctrl.dtsi

Antonio Borneo
2025-10-23T13:27:38Z

On board stm32mp257f-ev1, the propagation delay between eth1/eth2
and the external PHY requires a compensation to guarantee that no
packet get lost in all the working conditions.

Add I/O synchronization properties in pinctrl on all the RGMII
data pins, activating re-sampling on both edges of the clock.

Co-developed-by: Christophe Roullier <christophe.roullier@foss.st.com>
Signed-off-by: Christophe Roullier <christophe.roullier@foss.st.com>
Signed-off-by: Antonio Borneo <antonio.borneo@foss.st.com>
---
arch/arm64/boot/dts/st/stm32mp25-pinctrl.dtsi | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/arch/arm64/boot/dts/st/stm32mp25-pinctrl.dtsi b/arch/arm64/boot/dts/st/stm32mp25-pinctrl.dtsi
index e0d102eb61769..c34cd33cd855f 100644
--- a/arch/arm64/boot/dts/st/stm32mp25-pinctrl.dtsi
+++ b/arch/arm64/boot/dts/st/stm32mp25-pinctrl.dtsi
@@ -38,6 +38,7 @@ pins1 {
bias-disable;
drive-push-pull;
slew-rate = <3>;
+ st,io-sync = "data on both edges";
};
pins2 {
pinmux = <STM32_PINMUX('H', 9, AF10)>, /* ETH_RGMII_CLK125 */
@@ -53,6 +54,7 @@ pins3 {
<STM32_PINMUX('H', 13, AF10)>, /* ETH_RGMII_RXD3 */
<STM32_PINMUX('A', 11, AF10)>; /* ETH_RGMII_RX_CTL */
bias-disable;
+ st,io-sync = "data on both edges";
};
pins4 {
pinmux = <STM32_PINMUX('A', 14, AF10)>; /* ETH_RGMII_RX_CLK */
@@ -142,6 +144,7 @@ pins1 {
bias-disable;
drive-push-pull;
slew-rate = <3>;
+ st,io-sync = "data on both edges";
};
pins2 {
pinmux = <STM32_PINMUX('F', 8, AF10)>, /* ETH_RGMII_CLK125 */
@@ -164,6 +167,7 @@ pins4 {
<STM32_PINMUX('C', 11, AF10)>, /* ETH_RGMII_RXD3 */
<STM32_PINMUX('C', 3, AF10)>; /* ETH_RGMII_RX_CTL */
bias-disable;
+ st,io-sync = "data on both edges";
};
pins5 {
pinmux = <STM32_PINMUX('F', 6, AF10)>; /* ETH_RGMII_RX_CLK */
--
2.34.1