Add support to provide refclk to PCIe connector.

Signed-off-by: Kishon Vijay Abraham I <kis...@ti.com>
---
 drivers/pci/controller/cadence/pci-j721e.c | 22 +++++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/controller/cadence/pci-j721e.c 
b/drivers/pci/controller/cadence/pci-j721e.c
index dac1ac8a7615..7f9dd34b98a9 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 <kis...@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 +411,20 @@ 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)) {
+                       ret = PTR_ERR(clk);
+                       dev_err(dev, "failed to get pcie_refclk\n");
+                       goto err_pcie_setup;
+               }
+
+               ret = clk_prepare_enable(clk);
+               if (ret) {
+                       dev_err(dev, "failed to enable pcie_refclk\n");
+                       goto err_get_sync;
+               }
+               pcie->refclk = clk;
+
                /*
                 * "Power Sequencing and Reset Signal Timings" table in
                 * PCI EXPRESS CARD ELECTROMECHANICAL SPECIFICATION, REV. 3.0
@@ -422,8 +439,10 @@ static int j721e_pcie_probe(struct platform_device *pdev)
                }
 
                ret = cdns_pcie_host_setup(rc);
-               if (ret < 0)
+               if (ret < 0) {
+                       clk_disable_unprepare(pcie->refclk);
                        goto err_pcie_setup;
+               }
 
                break;
        case PCI_MODE_EP:
@@ -476,6 +495,7 @@ static int j721e_pcie_remove(struct platform_device *pdev)
        struct cdns_pcie *cdns_pcie = pcie->cdns_pcie;
        struct device *dev = &pdev->dev;
 
+       clk_disable_unprepare(pcie->refclk);
        cdns_pcie_disable_phy(cdns_pcie);
        pm_runtime_put(dev);
        pm_runtime_disable(dev);
-- 
2.17.1

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