[PATCH 7/7] blackfin: convert to clocksource_register_hz

From: John Stultz
Date: Wed Oct 20 2010 - 19:45:54 EST


This converts the blackfin clocksource to use clocksource_register_hz.

This is untested, so any assistance in testing would be appreciated!

Signed-off-by: John Stultz <johnstul@xxxxxxxxxx>
CC: Mike Frysinger <vapier@xxxxxxxxxx>
CC: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
arch/blackfin/kernel/time-ts.c | 35 ++---------------------------------
1 files changed, 2 insertions(+), 33 deletions(-)

diff --git a/arch/blackfin/kernel/time-ts.c b/arch/blackfin/kernel/time-ts.c
index 8c9a43d..4a01371 100644
--- a/arch/blackfin/kernel/time-ts.c
+++ b/arch/blackfin/kernel/time-ts.c
@@ -23,29 +23,6 @@
#include <asm/gptimers.h>
#include <asm/nmi.h>

-/* Accelerators for sched_clock()
- * convert from cycles(64bits) => nanoseconds (64bits)
- * basic equation:
- * ns = cycles / (freq / ns_per_sec)
- * ns = cycles * (ns_per_sec / freq)
- * ns = cycles * (10^9 / (cpu_khz * 10^3))
- * ns = cycles * (10^6 / cpu_khz)
- *
- * Then we use scaling math (suggested by george@xxxxxxxxxx) to get:
- * ns = cycles * (10^6 * SC / cpu_khz) / SC
- * ns = cycles * cyc2ns_scale / SC
- *
- * And since SC is a constant power of two, we can convert the div
- * into a shift.
- *
- * We can use khz divisor instead of mhz to keep a better precision, since
- * cyc2ns_scale is limited to 10^6 * 2^10, which fits in 32 bits.
- * (mathieu.desnoyers@xxxxxxxxxx)
- *
- * -johnstul@xxxxxxxxxx "math is hard, lets go shopping!"
- */
-
-#define CYC2NS_SCALE_FACTOR 10 /* 2^10, carefully chosen */

#if defined(CONFIG_CYCLES_CLOCKSOURCE)

@@ -63,7 +40,6 @@ static struct clocksource bfin_cs_cycles = {
.rating = 400,
.read = bfin_read_cycles,
.mask = CLOCKSOURCE_MASK(64),
- .shift = CYC2NS_SCALE_FACTOR,
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};

@@ -75,10 +51,7 @@ static inline unsigned long long bfin_cs_cycles_sched_clock(void)

static int __init bfin_cs_cycles_init(void)
{
- bfin_cs_cycles.mult = \
- clocksource_hz2mult(get_cclk(), bfin_cs_cycles.shift);
-
- if (clocksource_register(&bfin_cs_cycles))
+ if (clocksource_register_hz(&bfin_cs_cycles, get_cclk()))
panic("failed to register clocksource");

return 0;
@@ -111,7 +84,6 @@ static struct clocksource bfin_cs_gptimer0 = {
.rating = 350,
.read = bfin_read_gptimer0,
.mask = CLOCKSOURCE_MASK(32),
- .shift = CYC2NS_SCALE_FACTOR,
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};

@@ -125,10 +97,7 @@ static int __init bfin_cs_gptimer0_init(void)
{
setup_gptimer0();

- bfin_cs_gptimer0.mult = \
- clocksource_hz2mult(get_sclk(), bfin_cs_gptimer0.shift);
-
- if (clocksource_register(&bfin_cs_gptimer0))
+ if (clocksource_register_hz(&bfin_cs_gptimer0, get_sclk()))
panic("failed to register clocksource");

return 0;
--
1.6.0.4

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