PCI: imx6: Make reset-gpio optional

Some boards do not have a PCIe reset GPIO.  To avoid probe failure on these
boards, make the reset GPIO optional as well.

[bhelgaas: whitespace fixes]
Signed-off-by: Marek Vasut <marex@denx.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Jingoo Han <jg1.han@samsung.com>
Acked-by: Shawn Guo <shawn.guo@linaro.org>
Cc: Frank Li <lznuaa@gmail.com>
Cc: Harro Haan <hrhaan@gmail.com>
Cc: Mohit KUMAR <Mohit.KUMAR@st.com>
Cc: Pratyush Anand <pratyush.anand@st.com>
Cc: Richard Zhu <r65037@freescale.com>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Sean Cross <xobs@kosagi.com>
Cc: Siva Reddy Kallam <siva.kallam@samsung.com>
Cc: Srikanth T Shivanand <ts.srikanth@samsung.com>
Cc: Tim Harvey <tharvey@gateworks.com>
Cc: Troy Kisky <troy.kisky@boundarydevices.com>
Cc: Yinghai Lu <yinghai@kernel.org>

2 files changed, 15 insertions, 14 deletions

diff --git a/Documentation/devicetree/bindings/pci/designware-pcie.txt b/Documentation/devicetree/bindings/pci/designware-pcie.txt
index d5d26d443693..d6fae13ff062 100644
--- a/Documentation/devicetree/bindings/pci/designware-pcie.txt
+++ b/Documentation/devicetree/bindings/pci/designware-pcie.txt
@@ -19,6 +19,8 @@ Required properties:
         to define the mapping of the PCIe interface to interrupt
         numbers.
 - num-lanes: number of lanes to use
+
+Optional properties:
 - reset-gpio: gpio pin number of power good signal
 
 Optional properties for fsl,imx6q-pcie
diff --git a/drivers/pci/host/pci-imx6.c b/drivers/pci/host/pci-imx6.c
index 9fc1cb66c64e..1176bddee1cc 100644
--- a/drivers/pci/host/pci-imx6.c
+++ b/drivers/pci/host/pci-imx6.c
@@ -214,9 +214,12 @@ static int imx6_pcie_assert_core_reset(struct pcie_port *pp)
         regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1,
                         IMX6Q_GPR1_PCIE_REF_CLK_EN, 0 << 16);
 
-        gpio_set_value(imx6_pcie->reset_gpio, 0);
-        msleep(100);
-        gpio_set_value(imx6_pcie->reset_gpio, 1);
+        /* Some boards don't have PCIe reset GPIO. */
+        if (gpio_is_valid(imx6_pcie->reset_gpio)) {
+                gpio_set_value(imx6_pcie->reset_gpio, 0);
+                msleep(100);
+                gpio_set_value(imx6_pcie->reset_gpio, 1);
+        }
 
         return 0;
 }
@@ -432,17 +435,13 @@ static int __init imx6_pcie_probe(struct platform_device *pdev)
 
         /* Fetch GPIOs */
         imx6_pcie->reset_gpio = of_get_named_gpio(np, "reset-gpio", 0);
-        if (!gpio_is_valid(imx6_pcie->reset_gpio)) {
-                dev_err(&pdev->dev, "no reset-gpio defined\n");
-                ret = -ENODEV;
-        }
-        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;
+        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;
+                }
         }
 
         imx6_pcie->power_on_gpio = of_get_named_gpio(np, "power-on-gpio", 0);