[PATCH 3/5] PCI: qcom: Keep PERST# GPIO state as-is during probe
Konrad Dybcio
konrad.dybcio at oss.qualcomm.com
Fri Jan 9 03:14:05 PST 2026
On 1/9/26 8:21 AM, Krishna Chaitanya Chundru wrote:
> The PERST# signal is used to reset PCIe devices. Currently, the driver
> requests the GPIO with GPIOD_OUT_HIGH, which forces the line high
> during probe. This can unintentionally assert reset early, breaking
^ de-assert, probably?
Konrad
> link retention or causing unexpected device behavior.
>
> Change the request to use GPIOD_ASIS so the driver preserves the
> existing state configured by the bootloader or firmware. This allows
> platforms that manage PERST# externally to maintain proper reset
> sequencing.
>
> Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru at oss.qualcomm.com>
> ---
> drivers/pci/controller/dwc/pcie-qcom.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
> index 7b92e7a1c0d9364a9cefe1450818f9cbfc7fd3ac..9342f9c75f1c3017b55614069a7aa821a6fb8da7 100644
> --- a/drivers/pci/controller/dwc/pcie-qcom.c
> +++ b/drivers/pci/controller/dwc/pcie-qcom.c
> @@ -1711,7 +1711,7 @@ static int qcom_pcie_parse_port(struct qcom_pcie *pcie, struct device_node *node
> int ret;
>
> reset = devm_fwnode_gpiod_get(dev, of_fwnode_handle(node),
> - "reset", GPIOD_OUT_HIGH, "PERST#");
> + "reset", GPIOD_ASIS, "PERST#");
> if (IS_ERR(reset))
> return PTR_ERR(reset);
>
> @@ -1772,7 +1772,7 @@ static int qcom_pcie_parse_legacy_binding(struct qcom_pcie *pcie)
> if (IS_ERR(phy))
> return PTR_ERR(phy);
>
> - reset = devm_gpiod_get_optional(dev, "perst", GPIOD_OUT_HIGH);
> + reset = devm_gpiod_get_optional(dev, "perst", GPIOD_ASIS);
> if (IS_ERR(reset))
> return PTR_ERR(reset);
>
>
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