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PCI: imx6: Allow probe deferral by reset GPIO 

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.
To support such designs, allow reset GPIO request to defer probing of the
driver.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
Cc: yurovsky@gmail.com
Cc: Fabio Estevam <fabio.estevam@nxp.com>
Cc: Dong Aisheng <dongas86@gmail.com>
Cc: linux-arm-kernel@lists.infradead.org
This commit is contained in:
Andrey Smirnov 2017-03-28 08:42:50 -07:00 committed by Bjorn Helgaas
parent 9b3fe6796d
commit bde4a5a00e
1 changed files with 17 additions and 8 deletions
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25
drivers/pci/dwc/pci-imx6.c
View File

@ -595,8 +595,8 @@ static struct dw_pcie_host_ops imx6_pcie_host_ops = {
.host_init = imx6_pcie_host_init,
};
static int __init imx6_add_pcie_port(struct imx6_pcie *imx6_pcie,
struct platform_device *pdev)
static int imx6_add_pcie_port(struct imx6_pcie *imx6_pcie,
struct platform_device *pdev)
{
struct dw_pcie *pci = imx6_pcie->pci;
struct pcie_port *pp = &pci->pp;
@ -636,7 +636,7 @@ static const struct dw_pcie_ops dw_pcie_ops = {
.link_up = imx6_pcie_link_up,
};
static int __init imx6_pcie_probe(struct platform_device *pdev)
static int imx6_pcie_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct dw_pcie *pci;
@ -660,10 +660,6 @@ static int __init imx6_pcie_probe(struct platform_device *pdev)
imx6_pcie->variant =
(enum imx6_pcie_variants)of_device_get_match_data(dev);
/* Added for PCI abort handling */
hook_fault_code(16 + 6, imx6q_pcie_abort_handler, SIGBUS, 0,
"imprecise external abort");
dbi_base = platform_get_resource(pdev, IORESOURCE_MEM, 0);
pci->dbi_base = devm_ioremap_resource(dev, dbi_base);
if (IS_ERR(pci->dbi_base))
@ -683,6 +679,8 @@ 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) {
return imx6_pcie->reset_gpio;
}
/* Fetch clocks */
@ -796,11 +794,22 @@ 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);
/*
* Since probe() can be deferred we need to make sure that
* hook_fault_code is not called after __init memory is freed
* by kernel and since imx6q_pcie_abort_handler() is a no-op,
* we can install the handler here without risking it
* accessing some uninitialized driver state.
*/
hook_fault_code(16 + 6, imx6q_pcie_abort_handler, SIGBUS, 0,
"imprecise external abort");
return platform_driver_register(&imx6_pcie_driver);
}
device_initcall(imx6_pcie_init);