[PATCH 4.19 104/190] PCI: qcom: Dont deassert reset GPIO during probe

Greg Kroah-Hartman
2019-09-13T13:16:05Z

[ Upstream commit 02b485e31d98265189b91f3e69c43df2ed50610c ]

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
Signed-off-by: Sasha Levin <sashal@kernel.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 79f06c76ae071..e292801fff7fd 100644
--- a/drivers/pci/controller/dwc/pcie-qcom.c
+++ b/drivers/pci/controller/dwc/pcie-qcom.c
@@ -1230,7 +1230,7 @@ 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;
--
2.20.1