Acquiring the reset GPIO low means that reset is being deasserted, this is followed almost immediately with qcom_pcie_host_init() asserting it, initializing it and then finally deasserting it again, for the link to come up.
Some PCIe devices requires a minimum time between the initial deassert and subsequent reset cycles. In a platform that boots with the reset GPIO asserted this requirement is being violated by this deassert/assert pulse.
Acquiring the reset GPIO high will prevent this by matching the state to the subsequent asserted state.
Cc: stable@vger.kernel.org Signed-off-by: Bjorn Andersson bjorn.andersson@linaro.org --- drivers/pci/controller/dwc/pcie-qcom.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c index d185ea5fe996..a7f703556790 100644 --- a/drivers/pci/controller/dwc/pcie-qcom.c +++ b/drivers/pci/controller/dwc/pcie-qcom.c @@ -1228,7 +1228,7 @@ static int qcom_pcie_probe(struct platform_device *pdev)
pcie->ops = of_device_get_match_data(dev);
- pcie->reset = devm_gpiod_get_optional(dev, "perst", GPIOD_OUT_LOW); + pcie->reset = devm_gpiod_get_optional(dev, "perst", GPIOD_OUT_HIGH); if (IS_ERR(pcie->reset)) { ret = PTR_ERR(pcie->reset); goto err_pm_runtime_put;