On Mon, Mar 28, 2016 at 2:45 PM, Fabio Estevam <festevam@xxxxxxxxx> wrote:
> From: Fabio Estevam <fabio.estevam@xxxxxxx>
>
> Commit 5c5fb40de8f14 ("PCI: imx6: Add support for active-low reset GPIO")
> cause regressions on some boards like MX6 Gateworks Ventana, for example.
>
> The reason for the breakage is that this commit sets the gpio polarity
> in the wrong logic level.
>
> Also, the commit log is wrong because active-low reset GPIO is what the
> driver used to support since the beginning.
>
> So keep the old behavior that ignores the gpio polarity specified in
> the device tree and treat the PCI reset GPIO as active-low.
>
> Cc: <stable@xxxxxxxxxxxxxxx> # 4.5
> Reported-by: Krzysztof Hałasa <khalasa@xxxxxxx>
> Signed-off-by: Fabio Estevam <fabio.estevam@xxxxxxx>
> ---
> Changes since v1:
> - Improve wording of commit log (Tim)
>
> drivers/pci/host/pci-imx6.c | 20 ++++++++++++++------
> 1 file changed, 14 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/pci/host/pci-imx6.c b/drivers/pci/host/pci-imx6.c
> index eb5a275..2f817fa 100644
> --- a/drivers/pci/host/pci-imx6.c
> +++ b/drivers/pci/host/pci-imx6.c
> @@ -32,7 +32,7 @@
> #define to_imx6_pcie(x) container_of(x, struct imx6_pcie, pp)
>
> struct imx6_pcie {
> - struct gpio_desc *reset_gpio;
> + int reset_gpio;
> struct clk *pcie_bus;
> struct clk *pcie_phy;
> struct clk *pcie;
> @@ -309,10 +309,10 @@ static int imx6_pcie_deassert_core_reset(struct pcie_port *pp)
> usleep_range(200, 500);
>
> /* Some boards don't have PCIe reset GPIO. */
> - if (imx6_pcie->reset_gpio) {
> - gpiod_set_value_cansleep(imx6_pcie->reset_gpio, 0);
> + if (gpio_is_valid(imx6_pcie->reset_gpio)) {
> + gpio_set_value_cansleep(imx6_pcie->reset_gpio, 0);
> msleep(100);
> - gpiod_set_value_cansleep(imx6_pcie->reset_gpio, 1);
> + gpio_set_value_cansleep(imx6_pcie->reset_gpio, 1);
> }
> return 0;
>
> @@ -523,6 +523,7 @@ static int __init imx6_pcie_probe(struct platform_device *pdev)
> {
> struct imx6_pcie *imx6_pcie;
> struct pcie_port *pp;
> + struct device_node *np = pdev->dev.of_node;
> struct resource *dbi_base;
> struct device_node *node = pdev->dev.of_node;
> int ret;
> @@ -544,8 +545,15 @@ static int __init imx6_pcie_probe(struct platform_device *pdev)
> return PTR_ERR(pp->dbi_base);
>
> /* Fetch GPIOs */
> - imx6_pcie->reset_gpio = devm_gpiod_get_optional(&pdev->dev, "reset",
> - GPIOD_OUT_LOW);
> + imx6_pcie->reset_gpio = of_get_named_gpio(np, "reset-gpio", 0);
> + if (gpio_is_valid(imx6_pcie->reset_gpio)) {
> + ret = devm_gpio_request_one(&pdev->dev, imx6_pcie->reset_gpio,
> + GPIOF_OUT_INIT_LOW, "PCIe reset");
> + if (ret) {
> + dev_err(&pdev->dev, "unable to get reset gpio\n");
> + return ret;
> + }
> + }
>
> /* Fetch clocks */
> imx6_pcie->pcie_phy = devm_clk_get(&pdev->dev, "pcie_phy");
> --
> 1.9.1
>
Fabio/Krzysztof - thanks for finding this regression that breaks PCI
on most IMX6. I verified reverting this resolves Gateworks Ventana PCI
breakage in v4.5.
Acked-by: Tim Harvey <tharvey@xxxxxxxxxxxxx>
Regards,
Tim
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