Commit-ID: 4e53aa2fde4124878fc6b2183d6e8ec46e12ceb0
Gitweb: http://git.kernel.org/tip/4e53aa2fde4124878fc6b2183d6e8ec46e12ceb0
Author: Nicolai Stange <nicstange@xxxxxxxxx>
AuthorDate: Mon, 6 Feb 2017 22:12:02 +0100
Committer: John Stultz <john.stultz@xxxxxxxxxx>
CommitDate: Thu, 23 Mar 2017 12:14:03 -0700
clocksource: em_sti: Compute rate before registration
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@xxxxxxxxx>
Signed-off-by: John Stultz <john.stultz@xxxxxxxxxx>
---
drivers/clocksource/em_sti.c | 25 ++++++++++++-------------
1 file changed, 12 insertions(+), 13 deletions(-)
diff --git a/drivers/clocksource/em_sti.c b/drivers/clocksource/em_sti.c
index 6c0955a..bc48cbf 100644
--- a/drivers/clocksource/em_sti.c
+++ b/drivers/clocksource/em_sti.c
@@ -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);
--
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