From: nicolas.ferre@atmel•com (Nicolas Ferre)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH] clocksource: timer-atmel-pit: don't suspend/resume if unused
Date: Mon, 12 Jan 2015 15:04:00 +0100 [thread overview]
Message-ID: <54B3D450.7050405@atmel.com> (raw)
In-Reply-To: <1418911523-28492-1-git-send-email-nicolas.ferre@atmel.com>
Le 18/12/2014 15:05, Nicolas Ferre a ?crit :
> From: Sylvain Rochet <sylvain.rochet@finsecur•com>
>
> Waiting for PIT to stop counting takes a long time:
> 1/(Master clock/prescaler/PIVR)
> = 1/(133 MHz /16 /2^20)
> = 126 ms
>
> Up to 126 ms if master clock is set to 133 MHz, skipping suspend/resume
> of the unused PIT device reduce (suspend time + resume time) from ~140 ms
> to ~17 ms.
>
> Signed-off-by: Sylvain Rochet <sylvain.rochet@finsecur•com>
> [nicolas.ferre at atmel.com: move to newer clocksource driver]
> Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel•com>
> Cc: Daniel Lezcano <daniel.lezcano@linaro•org>
> ---
> Hi Sylvain,
>
> I re-worked (and "Acked") your patch so it can be applied on the newer Mainline
> kernels. Beware, I changed the "subject line" as well. The PIT driver moved
> recently (3.18).
>
> Daniel,
> Can you take this patch in your tree?
Hi Daniel,
Anything prevents this patch from being merged (aka ping ;-))?
Bye,
> Thanks, bye.
> Nicolas.
>
> drivers/clocksource/timer-atmel-pit.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/drivers/clocksource/timer-atmel-pit.c b/drivers/clocksource/timer-atmel-pit.c
> index b5b4d4585c9a..5408bc7c68d8 100644
> --- a/drivers/clocksource/timer-atmel-pit.c
> +++ b/drivers/clocksource/timer-atmel-pit.c
> @@ -123,6 +123,10 @@ static void at91sam926x_pit_suspend(struct clock_event_device *cedev)
> {
> struct pit_data *data = clkevt_to_pit_data(cedev);
>
> + /* Don't suspend PIT if unused */
> + if (cedev->mode == CLOCK_EVT_MODE_UNUSED)
> + return;
> +
> /* Disable timer */
> pit_write(data->base, AT91_PIT_MR, 0);
> }
> @@ -145,6 +149,10 @@ static void at91sam926x_pit_resume(struct clock_event_device *cedev)
> {
> struct pit_data *data = clkevt_to_pit_data(cedev);
>
> + /* Don't resume PIT if unused */
> + if (cedev->mode == CLOCK_EVT_MODE_UNUSED)
> + return;
> +
> at91sam926x_pit_reset(data);
> }
>
>
--
Nicolas Ferre
next prev parent reply other threads:[~2015-01-12 14:04 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-18 14:05 [PATCH] clocksource: timer-atmel-pit: don't suspend/resume if unused Nicolas Ferre
2015-01-12 14:04 ` Nicolas Ferre [this message]
2015-01-12 14:22 ` Daniel Lezcano
2015-01-13 10:47 ` Thomas Gleixner
2015-01-15 11:41 ` Daniel Lezcano
2015-01-15 11:52 ` Alexandre Belloni
2015-01-15 12:23 ` Daniel Lezcano
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