zynq: Add clk framework support to zynq timer

If available use the clock framework to calculate the clock rate of the
zynq timer.
Signed-off-by: NStefan Herbrechtsmeier <stefan.herbrechtsmeier@weidmueller.com>
Signed-off-by: NMichal Simek <michal.simek@xilinx.com>

arch/arm/mach-zynq/timer.c

 /*
+ * Copyright (C) 2017 Weidmüller Interface GmbH & Co. KG
+ * Stefan Herbrechtsmeier <stefan.herbrechtsmeier@weidmueller.com>
+ *
  * Copyright (C) 2012 Michal Simek <monstr@monstr.eu>
  * Copyright (C) 2011-2012 Xilinx, Inc. All rights reserved.
  *
@@ -25,8 +28,10 @@
  * SPDX-License-Identifier:	GPL-2.0+
  */
 
+#include <clk.h>
 #include <common.h>
 #include <div64.h>
+#include <dm.h>
 #include <asm/io.h>
 #include <asm/arch/hardware.h>
 #include <asm/arch/clk.h>
@@ -56,6 +61,26 @@ int timer_init(void)
 			(TIMER_PRESCALE << SCUTIMER_CONTROL_PRESCALER_SHIFT) |
 			SCUTIMER_CONTROL_ENABLE_MASK;
 
+#if defined(CONFIG_CLK) || defined(CONFIG_SPL_CLK)
+	struct udevice *dev;
+	struct clk clk;
+	int ret;
+
+	ret = uclass_get_device_by_driver(UCLASS_CLK,
+		DM_GET_DRIVER(zynq_clk), &dev);
+	if (ret)
+		return ret;
+
+	clk.id = cpu_6or4x_clk;
+	ret = clk_request(dev, &clk);
+	if (ret < 0)
+		return ret;
+
+	gd->cpu_clk = clk_get_rate(&clk);
+
+	clk_free(&clk);
+#endif
+
 	gd->arch.timer_rate_hz = (gd->cpu_clk / 2) / (TIMER_PRESCALE + 1);
 
 	/* Load the timer counter register */