The patch below does not apply to the 4.19-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 02b485e31d98265189b91f3e69c43df2ed50610c Mon Sep 17 00:00:00 2001
From: Bjorn Andersson bjorn.andersson@linaro.org Date: Fri, 25 Jan 2019 15:26:16 -0800 Subject: [PATCH] PCI: qcom: Don't deassert reset GPIO during probe
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.
Acquire the reset GPIO high to prevent this situation by matching the state to the subsequent asserted state.
Fixes: 82a823833f4e ("PCI: qcom: Add Qualcomm PCIe controller driver") Signed-off-by: Bjorn Andersson bjorn.andersson@linaro.org [lorenzo.pieralisi@arm.com: updated commit log] Signed-off-by: Lorenzo Pieralisi lorenzo.pieralisi@arm.com Acked-by: Stanimir Varbanov svarbanov@mm-sol.com Cc: stable@vger.kernel.org
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;