[PATCH 2/3] PCI: imx6: Allow probe deferal by reset GPIO

From: Andrey Smirnov
Date: Thu Jan 19 2017 - 11:40:25 EST


Some designs implement reset GPIO via a GPIO expander connected to a
peripheral bus. One such example would be i.MX7 Sabre board where said
GPIO is provided by SPI shift register connected to a bitbanged SPI
bus. In order to support such designs allow reset GPIO request to defer
probing of the driver.

Cc: yurovsky@xxxxxxxxx
Cc: Richard Zhu <hongxing.zhu@xxxxxxx>
Cc: Lucas Stach <l.stach@xxxxxxxxxxxxxx>
Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Cc: Fabio Estevam <festevam@xxxxxxxxx>
Cc: Shawn Guo <shawnguo@xxxxxxxxxx>
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Andrey Smirnov <andrew.smirnov@xxxxxxxxx>
---
drivers/pci/host/pci-imx6.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/host/pci-imx6.c b/drivers/pci/host/pci-imx6.c
index 50a1291..574f026 100644
--- a/drivers/pci/host/pci-imx6.c
+++ b/drivers/pci/host/pci-imx6.c
@@ -653,6 +653,9 @@ static int __init imx6_pcie_probe(struct platform_device *pdev)
dev_err(dev, "unable to get reset gpio\n");
return ret;
}
+ } else if (imx6_pcie->reset_gpio == -EPROBE_DEFER) {
+ dev_info(dev, "probe is defered by reset GPIO\n");
+ return imx6_pcie->reset_gpio;
}

/* Fetch clocks */
@@ -746,11 +749,12 @@ static struct platform_driver imx6_pcie_driver = {
.name = "imx6q-pcie",
.of_match_table = imx6_pcie_of_match,
},
+ .probe = imx6_pcie_probe,
.shutdown = imx6_pcie_shutdown,
};

static int __init imx6_pcie_init(void)
{
- return platform_driver_probe(&imx6_pcie_driver, imx6_pcie_probe);
+ return platform_driver_register(&imx6_pcie_driver);
}
device_initcall(imx6_pcie_init);
--
2.9.3