Commit 4e53aa2f authored by Nicolai Stange's avatar Nicolai Stange Committed by John Stultz
Browse files

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: default avatarNicolai Stange <nicstange@gmail.com>
Signed-off-by: default avatarJohn Stultz <john.stultz@linaro.org>
parent 3814ae09

drivers/clocksource/em_sti.c

+12 −13
Original line number Diff line number Diff line
@@ -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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