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path: root/drivers/clocksource/tango_xtal.c
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Diffstat (limited to 'drivers/clocksource/tango_xtal.c')
-rw-r--r--drivers/clocksource/tango_xtal.c66
1 files changed, 66 insertions, 0 deletions
diff --git a/drivers/clocksource/tango_xtal.c b/drivers/clocksource/tango_xtal.c
new file mode 100644
index 000000000000..d297b30d2bc0
--- /dev/null
+++ b/drivers/clocksource/tango_xtal.c
@@ -0,0 +1,66 @@
+#include <linux/clocksource.h>
+#include <linux/sched_clock.h>
+#include <linux/of_address.h>
+#include <linux/printk.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/clk.h>
+
+static void __iomem *xtal_in_cnt;
+static struct delay_timer delay_timer;
+
+static unsigned long notrace read_xtal_counter(void)
+{
+ return readl_relaxed(xtal_in_cnt);
+}
+
+static u64 notrace read_sched_clock(void)
+{
+ return read_xtal_counter();
+}
+
+static cycle_t read_clocksource(struct clocksource *cs)
+{
+ return read_xtal_counter();
+}
+
+static struct clocksource tango_xtal = {
+ .name = "tango-xtal",
+ .rating = 350,
+ .read = read_clocksource,
+ .mask = CLOCKSOURCE_MASK(32),
+ .flags = CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
+static void __init tango_clocksource_init(struct device_node *np)
+{
+ struct clk *clk;
+ int xtal_freq, ret;
+
+ xtal_in_cnt = of_iomap(np, 0);
+ if (xtal_in_cnt == NULL) {
+ pr_err("%s: invalid address\n", np->full_name);
+ return;
+ }
+
+ clk = of_clk_get(np, 0);
+ if (IS_ERR(clk)) {
+ pr_err("%s: invalid clock\n", np->full_name);
+ return;
+ }
+
+ xtal_freq = clk_get_rate(clk);
+ delay_timer.freq = xtal_freq;
+ delay_timer.read_current_timer = read_xtal_counter;
+
+ ret = clocksource_register_hz(&tango_xtal, xtal_freq);
+ if (ret != 0) {
+ pr_err("%s: registration failed\n", np->full_name);
+ return;
+ }
+
+ sched_clock_register(read_sched_clock, 32, xtal_freq);
+ register_current_timer_delay(&delay_timer);
+}
+
+CLOCKSOURCE_OF_DECLARE(tango, "sigma,tick-counter", tango_clocksource_init);