PCI: kirin: Return -EPROBE_DEFER in case the gpio isn't ready

PCI host bridge driver can be probed before the gpiochip it requires,
so, of_get_named_gpio() can return -EPROBE_DEFER. Current code lets the
kirin_pcie_probe() directly return -ENODEV, which results in the PCI
host controller driver probe failure; with this error code the PCI host
controller driver will not be probed again when the gpiochip driver is
loaded.

Fix the above issue by letting kirin_pcie_probe() return -EPROBE_DEFER in
such a case.

Link: https://lore.kernel.org/r/20200918123800.19983-1-huobean@gmail.com
Signed-off-by: Bean Huo <beanhuo@micron.com>
[lorenzo.pieralisi@arm.com: commit log]
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

diff --git a/drivers/pci/controller/dwc/pcie-kirin.c b/drivers/pci/controller/dwc/pcie-kirin.c
index e496f51..74b88d1 100644 (file)
--- a/drivers/pci/controller/dwc/pcie-kirin.c
+++ b/drivers/pci/controller/dwc/pcie-kirin.c
@@ -507,8 +507,12 @@ static int kirin_pcie_probe(struct platform_device *pdev)
 
        kirin_pcie->gpio_id_reset = of_get_named_gpio(dev->of_node,
                                                      "reset-gpios", 0);
-       if (kirin_pcie->gpio_id_reset < 0)
+       if (kirin_pcie->gpio_id_reset == -EPROBE_DEFER) {
+               return -EPROBE_DEFER;
+       } else if (!gpio_is_valid(kirin_pcie->gpio_id_reset)) {
+               dev_err(dev, "unable to get a valid gpio pin\n");
                return -ENODEV;
+       }
 
        ret = kirin_pcie_power_on(kirin_pcie);
        if (ret)