korg/linux
0
0
Fork 0
mirror of https://mirrors.bfsu.edu.cn/git/linux.git synced 2024-11-11 04:18:39 +08:00
Code Issues Packages Projects Releases Wiki Activity

clocksource: em_sti: Compute rate before registration

Browse Source 
With the upcoming NTP correction related rate adjustments to be implemented
in the clockevents core, the latter needs to get informed about every rate
change of a clockevent device made after its registration.

Currently, em_sti violates this requirement in that it registers its
clockevent device with a dummy rate and sets its final rate through
clockevents_config() called from its ->set_state_oneshot().

This patch moves the setting of the clockevent device's rate to its
registration.

I checked all current em_sti users in arch/arm/mach-shmobile and right now,
none of them changes any rate in any clock tree relevant to em_sti after
their respective time_init(). Since all em_sti instances are created after
time_init(), none of them should ever observe any clock rate changes.

- Determine the ->rate value in em_sti_probe() at device probing rather
  than at first usage.
- Set the clockevent device's rate at its registration.
- Although not strictly necessary for the upcoming clockevent core changes,
  set the clocksource's rate at its registration for consistency.

Signed-off-by: Nicolai Stange <nicstange@gmail.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
This commit is contained in:
Nicolai Stange 2017-02-06 22:12:02 +01:00 committed by John Stultz
parent 3814ae092d
commit 4e53aa2fde
1 changed files with 12 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

25
drivers/clocksource/em_sti.c
View File

@ -84,9 +84,6 @@ static int em_sti_enable(struct em_sti_priv *p)
return ret;
}
/* configure channel, periodic mode and maximum timeout */
p->rate = clk_get_rate(p->clk);
/* reset the counter */
em_sti_write(p, STI_SET_H, 0x40000000);
em_sti_write(p, STI_SET_L, 0x00000000);
@ -205,13 +202,9 @@ static u64 em_sti_clocksource_read(struct clocksource *cs)
static int em_sti_clocksource_enable(struct clocksource *cs)
{
int ret;
struct em_sti_priv *p = cs_to_em_sti(cs);
ret = em_sti_start(p, USER_CLOCKSOURCE);
if (!ret)
__clocksource_update_freq_hz(cs, p->rate);
return ret;
return em_sti_start(p, USER_CLOCKSOURCE);
}
static void em_sti_clocksource_disable(struct clocksource *cs)
@ -240,8 +233,7 @@ static int em_sti_register_clocksource(struct em_sti_priv *p)
dev_info(&p->pdev->dev, "used as clock source\n");
/* Register with dummy 1 Hz value, gets updated in ->enable() */
clocksource_register_hz(cs, 1);
clocksource_register_hz(cs, p->rate);
return 0;
}
@ -263,7 +255,6 @@ static int em_sti_clock_event_set_oneshot(struct clock_event_device *ced)
dev_info(&p->pdev->dev, "used for oneshot clock events\n");
em_sti_start(p, USER_CLOCKEVENT);
clockevents_config(&p->ced, p->rate);
return 0;
}
@ -294,8 +285,7 @@ static void em_sti_register_clockevent(struct em_sti_priv *p)
dev_info(&p->pdev->dev, "used for clock events\n");
/* Register with dummy 1 Hz value, gets updated in ->set_state_oneshot() */
clockevents_config_and_register(ced, 1, 2, 0xffffffff);
clockevents_config_and_register(ced, p->rate, 2, 0xffffffff);
}
static int em_sti_probe(struct platform_device *pdev)
@ -344,6 +334,15 @@ static int em_sti_probe(struct platform_device *pdev)
return ret;
}
ret = clk_enable(p->clk);
if (ret < 0) {
dev_err(&p->pdev->dev, "cannot enable clock\n");
clk_unprepare(p->clk);
return ret;
}
p->rate = clk_get_rate(p->clk);
clk_disable(p->clk);
raw_spin_lock_init(&p->lock);
em_sti_register_clockevent(p);
em_sti_register_clocksource(p);