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Commit bde4a5a0 authored by Andrey Smirnov's avatar Andrey Smirnov Committed by Bjorn Helgaas
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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: default avatarAndrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: default avatarLucas 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
parent 9b3fe679

drivers/pci/dwc/pci-imx6.c

+17 −8
Original line number Diff line number Diff line
@@ -595,7 +595,7 @@ 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,

static int imx6_add_pcie_port(struct imx6_pcie *imx6_pcie,

			      struct platform_device *pdev)

{

	struct dw_pcie *pci = imx6_pcie->pci;
@@ -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);