[PATCH 5.0 129/238] PCI: qcom: Dont deassert reset GPIO during probe

From: Greg Kroah-Hartman
Date: Fri Mar 22 2019 - 08:20:05 EST


5.0-stable review patch. If anyone has any objections, please let me know.

------------------

From: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>

commit 02b485e31d98265189b91f3e69c43df2ed50610c upstream.

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@xxxxxxxxxx>
[lorenzo.pieralisi@xxxxxxx: updated commit log]
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
Acked-by: Stanimir Varbanov <svarbanov@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/pci/controller/dwc/pcie-qcom.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- 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 platfo

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;