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PCI: dra7xx: Add support to make GPIO drive PERST# line

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The PERST# line in am57x-evm is connected to a GPIO line and PERST# should
be driven high to indicate the clocks are stable (As per Figure 2-10: Power
Up of the PCIe CEM spec 3.0).

Add support to make GPIO drive PERST# line.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
This commit is contained in:
Kishon Vijay Abraham I 2015-07-28 19:09:09 +05:30 committed by Bjorn Helgaas
parent 389c7094ec
commit 78bdcad05e
2 changed files with 25 additions and 2 deletions
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3
Documentation/devicetree/bindings/pci/ti-pci.txt
View File

@ -23,6 +23,9 @@ PCIe Designware Controller
interrupt-map-mask,
interrupt-map : as specified in ../designware-pcie.txt
Optional Property:
- gpios : Should be added if a gpio line is required to drive PERST# line
Example:
axi {
compatible = "simple-bus";

24
drivers/pci/host/pci-dra7xx.c
View File

@ -17,6 +17,7 @@
#include <linux/irqdomain.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of_gpio.h>
#include <linux/pci.h>
#include <linux/phy/phy.h>
#include <linux/platform_device.h>
@ -336,6 +337,9 @@ static int __init dra7xx_pcie_probe(struct platform_device *pdev)
struct device *dev = &pdev->dev;
struct device_node *np = dev->of_node;
char name[10];
int gpio_sel;
enum of_gpio_flags flags;
unsigned long gpio_flags;
dra7xx = devm_kzalloc(dev, sizeof(*dra7xx), GFP_KERNEL);
if (!dra7xx)
@ -398,6 +402,22 @@ static int __init dra7xx_pcie_probe(struct platform_device *pdev)
goto err_get_sync;
}
gpio_sel = of_get_gpio_flags(dev->of_node, 0, &flags);
if (gpio_is_valid(gpio_sel)) {
gpio_flags = (flags & OF_GPIO_ACTIVE_LOW) ?
GPIOF_OUT_INIT_LOW : GPIOF_OUT_INIT_HIGH;
ret = devm_gpio_request_one(dev, gpio_sel, gpio_flags,
"pcie_reset");
if (ret) {
dev_err(&pdev->dev, "gpio%d request failed, ret %d\n",
gpio_sel, ret);
goto err_gpio;
}
} else if (gpio_sel == -EPROBE_DEFER) {
ret = -EPROBE_DEFER;
goto err_gpio;
}
reg = dra7xx_pcie_readl(dra7xx, PCIECTRL_DRA7XX_CONF_DEVICE_CMD);
reg &= ~LTSSM_EN;
dra7xx_pcie_writel(dra7xx, PCIECTRL_DRA7XX_CONF_DEVICE_CMD, reg);
@ -406,11 +426,11 @@ static int __init dra7xx_pcie_probe(struct platform_device *pdev)
ret = dra7xx_add_pcie_port(dra7xx, pdev);
if (ret < 0)
goto err_add_port;
goto err_gpio;
return 0;
err_add_port:
err_gpio:
pm_runtime_put(dev);
err_get_sync: