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

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>

diff --git a/Documentation/devicetree/bindings/pci/ti-pci.txt b/Documentation/devicetree/bindings/pci/ti-pci.txt
index 3d217911b3133ef35e762e6abc45e1180b7656e0..60e25161f35181bfd026b48519f43666d33f091e 100644 (file)
--- a/Documentation/devicetree/bindings/pci/ti-pci.txt
+++ b/Documentation/devicetree/bindings/pci/ti-pci.txt
@@ -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";

diff --git a/drivers/pci/host/pci-dra7xx.c b/drivers/pci/host/pci-dra7xx.c
index 3772aff7df4f060cbc511c615d574a52504dd4ff..abb85a157ce0e76483503893b4081f0f1ac63711 100644 (file)
--- a/drivers/pci/host/pci-dra7xx.c
+++ b/drivers/pci/host/pci-dra7xx.c
@@ -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: