[PATCH v3 2/4] PCI: qcom: Keep PERST# GPIO state as-is during probe

[Krishna Chaitanya Chundru]

The PERST# signal is used to reset PCIe devices. Requesting the GPIO with
GPIOD_OUT_HIGH forces the line high during probe, which can unintentionally
assert reset on devices already out of reset and break proper link
sequencing.

Change the request to use GPIOD_ASIS so the driver preserves the existing
GPIO state configured by the bootloader or firmware. This allows platforms
that manage PERST# externally to maintain correct reset sequencing. PERST#
is asserted explicitly later during qcom_pcie_host_init(), so forcing it
high at probe time is unnecessary.

Tested-by: Qiang Yu <qiang.yu@xxxxxxxxxxxxxxxx>
Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@xxxxxxxxxxxxxxxx>
---
 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 d8eb52857f69..9ca620d4746a 100644
--- a/drivers/pci/controller/dwc/pcie-qcom.c
+++ b/drivers/pci/controller/dwc/pcie-qcom.c
@@ -1841,7 +1841,7 @@ static int qcom_pcie_parse_perst(struct qcom_pcie *pcie,
 		goto parse_child_node;
 
 	reset = devm_fwnode_gpiod_get(dev, of_fwnode_handle(np), "reset",
-				      GPIOD_OUT_HIGH, "PERST#");
+				      GPIOD_ASIS, "PERST#");
 	if (IS_ERR(reset)) {
 		/*
 		 * FIXME: GPIOLIB currently supports exclusive GPIO access only.
@@ -1918,7 +1918,7 @@ static int qcom_pcie_parse_ports(struct qcom_pcie *pcie)
 
 	if (of_find_property(dev->of_node, "perst-gpios", NULL)) {
 		pcie->reset = devm_gpiod_get_optional(dev, "perst",
-						      GPIOD_OUT_HIGH);
+						      GPIOD_ASIS);
 		if (IS_ERR(pcie->reset))
 			return PTR_ERR(pcie->reset);
 	}

-- 
2.34.1