Re: [PATCH v4 05/20] clocksource: samsung_pwm_timer: Handle suspend/resume correctly

[Daniel Lezcano <daniel.lezcano@linaro.org>]

On 07/20/2013 02:04 AM, Tomasz Figa wrote:
> Current suspend/resume handling of the driver was broken, because:
>  - periodic timer was being enabled in CLOCK_EVT_MODE_RESUME mode, which
>    does not seem to be correct behavior looking at other platforms,
>  - PWM divisors need to be restored, but they were not,
>  - clockevent interrupt mask needs to be restored, but it was not,
>  - clocksource was being restored in clockevent resume callback.
> 
> This patch fixes issues mentioned above, making suspend/resume handling
> in the driver correct.
> 
> Signed-off-by: Tomasz Figa <tomasz.figa@gmail.com>
> ---

Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>

>  drivers/clocksource/samsung_pwm_timer.c | 42 ++++++++++++++++++++++-----------
>  1 file changed, 28 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/clocksource/samsung_pwm_timer.c b/drivers/clocksource/samsung_pwm_timer.c
> index 753ffec..282e0e2 100644
> --- a/drivers/clocksource/samsung_pwm_timer.c
> +++ b/drivers/clocksource/samsung_pwm_timer.c
> @@ -197,17 +197,6 @@ static int samsung_set_next_event(unsigned long cycles,
>  	return 0;
>  }
>  
> -static void samsung_timer_resume(void)
> -{
> -	/* event timer restart */
> -	samsung_time_setup(pwm.event_id, pwm.clock_count_per_tick - 1);
> -	samsung_time_start(pwm.event_id, true);
> -
> -	/* source timer restart */
> -	samsung_time_setup(pwm.source_id, pwm.tcnt_max);
> -	samsung_time_start(pwm.source_id, true);
> -}
> -
>  static void samsung_set_mode(enum clock_event_mode mode,
>  				struct clock_event_device *evt)
>  {
> @@ -224,20 +213,29 @@ static void samsung_set_mode(enum clock_event_mode mode,
>  
>  	case CLOCK_EVT_MODE_UNUSED:
>  	case CLOCK_EVT_MODE_SHUTDOWN:
> -		break;
> -
>  	case CLOCK_EVT_MODE_RESUME:
> -		samsung_timer_resume();
>  		break;
>  	}
>  }
>  
> +static void samsung_clockevent_resume(struct clock_event_device *cev)
> +{
> +	samsung_timer_set_prescale(pwm.event_id, pwm.tscaler_div);
> +	samsung_timer_set_divisor(pwm.event_id, pwm.tdiv);
> +
> +	if (pwm.variant.has_tint_cstat) {
> +		u32 mask = (1 << pwm.event_id);
> +		writel(mask | (mask << 5), pwm.base + REG_TINT_CSTAT);
> +	}
> +}
> +
>  static struct clock_event_device time_event_device = {
>  	.name		= "samsung_event_timer",
>  	.features	= CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
>  	.rating		= 200,
>  	.set_next_event	= samsung_set_next_event,
>  	.set_mode	= samsung_set_mode,
> +	.resume		= samsung_clockevent_resume,
>  };
>  
>  static irqreturn_t samsung_clock_event_isr(int irq, void *dev_id)
> @@ -288,6 +286,20 @@ static void __init samsung_clockevent_init(void)
>  	}
>  }
>  
> +static void samsung_clocksource_suspend(struct clocksource *cs)
> +{
> +	samsung_time_stop(pwm.source_id);
> +}
> +
> +static void samsung_clocksource_resume(struct clocksource *cs)
> +{
> +	samsung_timer_set_prescale(pwm.source_id, pwm.tscaler_div);
> +	samsung_timer_set_divisor(pwm.source_id, pwm.tdiv);
> +
> +	samsung_time_setup(pwm.source_id, pwm.tcnt_max);
> +	samsung_time_start(pwm.source_id, true);
> +}
> +
>  static cycle_t samsung_clocksource_read(struct clocksource *c)
>  {
>  	return ~readl_relaxed(pwm.source_reg);
> @@ -297,6 +309,8 @@ static struct clocksource samsung_clocksource = {
>  	.name		= "samsung_clocksource_timer",
>  	.rating		= 250,
>  	.read		= samsung_clocksource_read,
> +	.suspend	= samsung_clocksource_suspend,
> +	.resume		= samsung_clocksource_resume,
>  	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
>  };
>  
> 


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