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 in pci-dra7xx driver to make gpio drive PERST#
line here.
Signed-off-by: Kishon Vijay Abraham I <kishon@xxxxxx>
---
Documentation/devicetree/bindings/pci/ti-pci.txt | 3 +++
drivers/pci/host/pci-dra7xx.c | 24 ++++++++++++++++++++--
2 files changed, 25 insertions(+), 2 deletions(-)
diff --git a/Documentation/devicetree/bindings/pci/ti-pci.txt b/Documentation/devicetree/bindings/pci/ti-pci.txt
index 3d21791..60e2516 100644
--- 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 7acc833..d3d0faf 100644
--- 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:
--
1.7.9.5
--
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