[PATCH] Helper function clocksource_khz2mult in clock.c
Vikram Narayanan
vikram186 at gmail.com
Mon May 30 17:21:45 EDT 2011
Hi,
Won't this helper function be a good one to add in the clock.c code?
Taken from the kernel file "include/linux/clocksource.h"
If it can be, please find below the patch.
---
diff --git a/common/clock.c b/common/clock.c
index 15df0ab..b07b449 100644
--- a/common/clock.c
+++ b/common/clock.c
@@ -57,6 +57,31 @@ uint64_t get_time_ns(void)
EXPORT_SYMBOL(get_time_ns);
/**
+ * clocksource_khz2mult - calculates mult from khz and shift
+ * @khz: Clocksource frequency in KHz
+ * @shift_constant: Clocksource shift factor
+ *
+ * Helper functions that converts a khz counter frequency to a
timsource
+ * multiplier, given the clocksource shift value
+ */
+static inline u32 clocksource_khz2mult(u32 khz, u32 shift_constant)
+{
+ /* khz = cyc/(Million ns)
+ * mult/2^shift = ns/cyc
+ * mult = ns/cyc * 2^shift
+ * mult = 1Million/khz * 2^shift
+ * mult = 1000000 * 2^shift / khz
+ * mult = (1000000<<shift) / khz
+ */
+ u64 tmp = ((u64)1000000) << shift_constant;
+
+ tmp += khz/2; /* round for do_div */
+ do_div(tmp, khz);
+
+ return (u32)tmp;
+}
+
+/**
* clocksource_hz2mult - calculates mult from hz and shift
* @hz: Clocksource frequency in Hz
* @shift_constant: Clocksource shift factor
-
Thanks,
Vikram
More information about the barebox
mailing list