From: Bjorn Andersson <bjorn.andersson@linaro.org>
To: Stanimir Varbanov <svarbanov@mm-sol.com>,
Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-pci@vger.kernel.org, linux-arm-msm@vger.kernel.org,
linux-kernel@vger.kernel.org,
Khasim Syed Mohammed <khasim.mohammed@linaro.org>,
Niklas Cassel <niklas.cassel@linaro.org>,
stable@vger.kernel.org
Subject: [PATCH] PCI: qcom: Don't deassert reset GPIO during probe
Date: Fri, 25 Jan 2019 15:26:16 -0800 [thread overview]
Message-ID: <20190125232616.25714-1-bjorn.andersson@linaro.org> (raw)
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;
--
2.18.0
next reply other threads:[~2019-01-25 23:26 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-25 23:26 Bjorn Andersson [this message]
2019-02-08 14:54 ` [PATCH] PCI: qcom: Don't deassert reset GPIO during probe Stanimir Varbanov
2019-02-13 15:23 ` Lorenzo Pieralisi
2019-02-19 5:16 ` Bjorn Andersson
2019-02-19 11:10 ` Lorenzo Pieralisi
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