Add support to provide refclk to PCIe connector.

Signed-off-by: Kishon Vijay Abraham I <redacted>
---
 drivers/pci/controller/cadence/pci-j721e.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/drivers/pci/controller/cadence/pci-j721e.c b/drivers/pci/controller/cadence/pci-j721e.c
index dac1ac8a7615..8ec6d9c3e164 100644
--- a/drivers/pci/controller/cadence/pci-j721e.c
+++ b/drivers/pci/controller/cadence/pci-j721e.c

@@ -6,6 +6,7 @@
  * Author: Kishon Vijay Abraham I <kishon@ti.com>
  */
 
+#include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/gpio/consumer.h>
 #include <linux/io.h>

@@ -50,6 +51,7 @@ enum link_status {
 
 struct j721e_pcie {
 	struct device		*dev;
+	struct clk		*refclk;
 	u32			mode;
 	u32			num_lanes;
 	struct cdns_pcie	*cdns_pcie;

@@ -310,6 +312,7 @@ static int j721e_pcie_probe(struct platform_device *pdev)
 	struct cdns_pcie_ep *ep;
 	struct gpio_desc *gpiod;
 	void __iomem *base;
+	struct clk *clk;
 	u32 num_lanes;
 	u32 mode;
 	int ret;

@@ -408,6 +411,19 @@ static int j721e_pcie_probe(struct platform_device *pdev)
 			goto err_get_sync;
 		}
 
+		clk = devm_clk_get_optional(dev, "pcie_refclk");
+		if (IS_ERR(clk)) {
+			dev_err(dev, "failed to get pcie_refclk\n");