3 files changed, 52 insertions, 0 deletions

diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index 96918e1f26a3..2c27b02f0860 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -191,3 +191,14 @@ config EM_TIMER_STI
 
 config CLKSRC_QCOM
         bool
+
+config CLKSRC_VERSATILE
+        bool "ARM Versatile (Express) reference platforms clock source"
+        depends on GENERIC_SCHED_CLOCK
+        select CLKSRC_OF
+        default y if MFD_VEXPRESS_SYSREG
+        help
+          This option enables clock source based on free running
+          counter available in the "System Registers" block of
+          ARM Versatile, RealView and Versatile Express reference
+          platforms.
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index 98cb6c51aa87..6f25bdffc176 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -39,3 +39,4 @@ obj-$(CONFIG_ARM_GLOBAL_TIMER)		+= arm_global_timer.o
 obj-$(CONFIG_CLKSRC_METAG_GENERIC)      += metag_generic.o
 obj-$(CONFIG_ARCH_HAS_TICK_BROADCAST)   += dummy_timer.o
 obj-$(CONFIG_ARCH_KEYSTONE)             += timer-keystone.o
+obj-$(CONFIG_CLKSRC_VERSATILE)          += versatile.o
diff --git a/drivers/clocksource/versatile.c b/drivers/clocksource/versatile.c
new file mode 100644
index 000000000000..e4c50ad2f9d9
--- /dev/null
+++ b/drivers/clocksource/versatile.c
@@ -0,0 +1,40 @@
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * Copyright (C) 2014 ARM Limited
+ */
+
+#include <linux/clocksource.h>
+#include <linux/io.h>
+#include <linux/of_address.h>
+#include <linux/sched_clock.h>
+
+#define SYS_24MHZ 0x05c
+
+static void __iomem *versatile_sys_24mhz;
+
+static u32 notrace versatile_sys_24mhz_read(void)
+{
+        return readl(versatile_sys_24mhz);
+}
+
+static void __init versatile_sched_clock_init(struct device_node *node)
+{
+        void __iomem *base = of_iomap(node, 0);
+
+        if (!base)
+                return;
+
+        versatile_sys_24mhz = base + SYS_24MHZ;
+
+        setup_sched_clock(versatile_sys_24mhz_read, 32, 24000000);
+}
+CLOCKSOURCE_OF_DECLARE(versatile, "arm,vexpress-sysreg",
+                versatile_sched_clock_init);