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clocksource: sh_cmt: __clocksource_updatefreq_hz() update 

This patch updates the clocksource part of the CMT driver
to make use of the __clocksource_updatefreq_hz() function.

Without this patch the old code uses clocksource_register()
together with a hack that assumes a never changing clock rate
(see clk_enable(), clk_get_rate() and clk_disable()).

The patch uses clocksource_register_hz() with 1 Hz as initial
value, then lets the ->enable() callback update the value
with __clocksource_updatefreq_hz() once the struct clk has
been enabled and the frequency is stable.

Signed-off-by: Magnus Damm <damm@opensource.se>
Acked-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
This commit is contained in:
Magnus Damm 2011-04-25 22:32:11 +09:00 committed by Paul Mundt
parent 31705e21f9
commit 3593f5fe40
1 changed files with 7 additions and 12 deletions
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19
drivers/clocksource/sh_cmt.c
View File

@ -416,11 +416,15 @@ static cycle_t sh_cmt_clocksource_read(struct clocksource *cs)
static int sh_cmt_clocksource_enable(struct clocksource *cs)
{
int ret;
struct sh_cmt_priv *p = cs_to_sh_cmt(cs);
p->total_cycles = 0;
return sh_cmt_start(p, FLAG_CLOCKSOURCE);
ret = sh_cmt_start(p, FLAG_CLOCKSOURCE);
if (!ret)
__clocksource_updatefreq_hz(cs, p->rate);
return ret;
}
static void sh_cmt_clocksource_disable(struct clocksource *cs)
@ -448,19 +452,10 @@ static int sh_cmt_register_clocksource(struct sh_cmt_priv *p,
cs->mask = CLOCKSOURCE_MASK(sizeof(unsigned long) * 8);
cs->flags = CLOCK_SOURCE_IS_CONTINUOUS;
/* clk_get_rate() needs an enabled clock */
clk_enable(p->clk);
p->rate = clk_get_rate(p->clk) / ((p->width == 16) ? 512 : 8);
clk_disable(p->clk);
/* TODO: calculate good shift from rate and counter bit width */
cs->shift = 0;
cs->mult = clocksource_hz2mult(p->rate, cs->shift);
dev_info(&p->pdev->dev, "used as clock source\n");
clocksource_register(cs);
/* Register with dummy 1 Hz value, gets updated in ->enable() */
clocksource_register_hz(cs, 1);
return 0;
}