usb: add clock support for generic EHCI

This driver is designed in a generic manner, so clocks should be
handled genericly as well.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

drivers/usb/host/ehci-generic.c

@@ -5,6 +5,7 @@
  */
 
 #include <common.h>
+#include <clk.h>
 #include <dm.h>
 #include "ehci.h"
 
@@ -21,6 +22,19 @@ static int ehci_usb_probe(struct udevice *dev)
 {
 	struct ehci_hccr *hccr = (struct ehci_hccr *)dev_get_addr(dev);
 	struct ehci_hcor *hcor;
+	int i;
+
+	for (i = 0; ; i++) {
+		struct udevice *clk_dev;
+		int clk_id;
+
+		clk_id = clk_get_by_index(dev, i, &clk_dev);
+		if (clk_id < 0)
+			break;
+		if (clk_enable(clk_dev, clk_id))
+			printf("failed to enable clock (dev=%s, id=%d)\n",
+			       clk_dev->name, clk_id);
+	}
 
 	hcor = (struct ehci_hcor *)((uintptr_t)hccr +
 				    HC_LENGTH(ehci_readl(&hccr->cr_capbase)));