[PATCH] arm64: dts: rockchip: align bindings to PCIe spec

Geraldo Nascimento
2025-11-05T05:55:25Z

The PERST# side-band signal is defined by PCIe spec as an open-drain
active-low signal that depends on a pull-up resistor to keep the
signal high when deasserted. Align bindings to the spec.

Note that the relevant driver hacks the active-low signal as
active-high and switches the normal polarity of PERST#
assertion/deassertion, 1 and 0 in that order, and instead uses
0 to signal low (assertion) and 1 to signal deassertion.

Incidentally, this change makes hardware that refused to work
with the Rockchip-IP PCIe core working for me, which was the
object of many fool's errands.

Signed-off-by: Geraldo Nascimento <geraldogabriel@gmail.com>
---
arch/arm64/boot/dts/rockchip/rk3399pro-vmarc-som.dtsi | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/boot/dts/rockchip/rk3399pro-vmarc-som.dtsi b/arch/arm64/boot/dts/rockchip/rk3399pro-vmarc-som.dtsi
index aa70776e898a..8dcb03708145 100644
--- a/arch/arm64/boot/dts/rockchip/rk3399pro-vmarc-som.dtsi
+++ b/arch/arm64/boot/dts/rockchip/rk3399pro-vmarc-som.dtsi
@@ -383,9 +383,9 @@ &pcie_phy {
};

&pcie0 {
- ep-gpios = <&gpio0 RK_PB4 GPIO_ACTIVE_HIGH>;
+ ep-gpios = <&gpio0 RK_PB4 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>;
num-lanes = <4>;
- pinctrl-0 = <&pcie_clkreqnb_cpm>;
+ pinctrl-0 = <&pcie_clkreqnb_cpm>, <&pcie_perst>;
pinctrl-names = "default";
vpcie0v9-supply = <&vcca_0v9>; /* VCC_0V9_S0 */
vpcie1v8-supply = <&vcca_1v8>; /* VCC_1V8_S0 */
@@ -408,6 +408,10 @@ pcie {
pcie_pwr: pcie-pwr {
rockchip,pins = <4 RK_PD4 RK_FUNC_GPIO &pcfg_pull_up>;
};
+ pcie_perst: pcie-perst {
+ rockchip,pins = <0 RK_PB4 RK_FUNC_GPIO &pcfg_pull_up>;
+ };
+
};

pmic {
--
2.49.0