Merge branch 'remotes/lorenzo/pci/xilinx-nwl'

- Document optional clock DT property (Michal Simek)

- Enable PCIe ref clock (Hyun Kwon)

* remotes/lorenzo/pci/xilinx-nwl:
  PCI: xilinx-nwl: Enable the clock through CCF
  dt-bindings: pci: xilinx-nwl: Document optional clock property

Author: bjorn-helgaas

Documentation/devicetree/bindings/pci/xilinx-nwl-pcie.txt

@@ -35,6 +35,7 @@ Required properties:
 
 Optional properties:
 - dma-coherent: present if DMA operations are coherent
+- clocks: Input clock specifier. Refer to common clock bindings
 
 Example:
 ++++++++

drivers/pci/controller/pcie-xilinx-nwl.c

@@ -6,6 +6,7 @@
  * (C) Copyright 2014 - 2015, Xilinx, Inc.
  */
 
+#include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/interrupt.h>
 #include <linux/irq.h>
@@ -169,6 +170,7 @@ struct nwl_pcie {
 	u8 last_busno;
 	struct nwl_msi msi;
 	struct irq_domain *legacy_irq_domain;
+	struct clk *clk;
 	raw_spinlock_t leg_mask_lock;
 };
 
@@ -816,6 +818,16 @@ static int nwl_pcie_probe(struct platform_device *pdev)
 		return err;
 	}
 
+	pcie->clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(pcie->clk))
+		return PTR_ERR(pcie->clk);
+
+	err = clk_prepare_enable(pcie->clk);
+	if (err) {
+		dev_err(dev, "can't enable PCIe ref clock\n");
+		return err;
+	}
+
 	err = nwl_pcie_bridge_init(pcie);
 	if (err) {
 		dev_err(dev, "HW Initialization failed\n");