[PATCH v2] arm64: dts: ti: k3-am642-sr-som: mux ethernet phy reset signals input

[Josua Mayer]

Specifically on AM64 SoM design, the DP83869 phys have a chance to lock
up if reset gpio changes state. Update the pinmux to input-only,
strongly enforcing that these signals are left floating at all times.

This avoids sporadic phy initialisation errors mostly encountered during
power-on and reset. In this state the phys respond to all mdio messages
with a constant response, recovering only after power-cycle.

Signed-off-by: Josua Mayer <josua@xxxxxxxxxxxxx>
---
Changes in v2:
- update commit message with additional details
- rebased on v6.11-rc1
- Link to v1: https://lore.kernel.org/r/20240704-am64-phy-lockup-v1-1-4a38ded44f9d@xxxxxxxxxxxxx
---
 arch/arm64/boot/dts/ti/k3-am642-sr-som.dtsi | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/boot/dts/ti/k3-am642-sr-som.dtsi b/arch/arm64/boot/dts/ti/k3-am642-sr-som.dtsi
index c19d0b8bbf0f..b1f06071df4c 100644
--- a/arch/arm64/boot/dts/ti/k3-am642-sr-som.dtsi
+++ b/arch/arm64/boot/dts/ti/k3-am642-sr-som.dtsi
@@ -320,7 +320,7 @@ AM64X_IOPAD(0x0278, PIN_INPUT, 7) /* EXTINTn.GPIO1_70 */
 	ethernet_phy0_default_pins: ethernet-phy0-default-pins {
 		pinctrl-single,pins = <
 			/* reset */
-			AM64X_IOPAD(0x0154, PIN_OUTPUT, 7) /* PRG1_PRU1_GPO19.GPIO0_84 */
+			AM64X_IOPAD(0x0154, PIN_INPUT, 7) /* PRG1_PRU1_GPO19.GPIO0_84 */
 			/* reference clock */
 			AM64X_IOPAD(0x0274, PIN_OUTPUT, 5) /* EXT_REFCLK1.CLKOUT0 */
 		>;
@@ -329,7 +329,7 @@ AM64X_IOPAD(0x0274, PIN_OUTPUT, 5) /* EXT_REFCLK1.CLKOUT0 */
 	ethernet_phy1_default_pins: ethernet-phy1-default-pins {
 		pinctrl-single,pins = <
 			/* reset */
-			AM64X_IOPAD(0x0150, PIN_OUTPUT, 7) /* PRG1_PRU1_GPO18.GPIO0_20 */
+			AM64X_IOPAD(0x0150, PIN_INPUT, 7) /* PRG1_PRU1_GPO18.GPIO0_20 */
 			/* led0, external pull-down on SoM */
 			AM64X_IOPAD(0x0128, PIN_INPUT, 7) /* PRG1_PRU1_GPO8.GPIO0_73 */
 			/* led1/rxer */
@@ -340,7 +340,7 @@ AM64X_IOPAD(0x011c, PIN_INPUT, 7) /* PRG1_PRU1_GPO5.GPIO0_70 */
 	ethernet_phy2_default_pins: ethernet-phy2-default-pins {
 		pinctrl-single,pins = <
 			/* reset */
-			AM64X_IOPAD(0x00d4, PIN_OUTPUT, 7) /* PRG1_PRU0_GPO7.GPIO0_52 */
+			AM64X_IOPAD(0x00d4, PIN_INPUT, 7) /* PRG1_PRU0_GPO7.GPIO0_52 */
 			/* led0, external pull-down on SoM */
 			AM64X_IOPAD(0x00d8, PIN_INPUT, 7) /* PRG1_PRU0_GPO8.GPIO0_53 */
 			/* led1/rxer */

---
base-commit: 8400291e289ee6b2bf9779ff1c83a291501f017b
change-id: 20240704-am64-phy-lockup-107ea5ffa228

Best regards,
-- 
Josua Mayer <josua@xxxxxxxxxxxxx>