linux-kernel - Re: [PATCH] rtc: rtc-omap: Replace mdelay() with msleep() in omap_rtc_power

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Message-ID: <20180827205517.GD24549@piout.net>
Date:   Mon, 27 Aug 2018 22:55:17 +0200
From:   Alexandre Belloni <alexandre.belloni@...tlin.com>
To:     Jia-Ju Bai <baijiaju1990@...il.com>, johan@...nel.org,
        j-keerthy@...com
Cc:     a.zummo@...ertech.it, linux-rtc@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] rtc: rtc-omap: Replace mdelay() with msleep() in
 omap_rtc_power_off()

Hi,

On 30/07/2018 21:53:14+0800, Jia-Ju Bai wrote:
> omap_rtc_power_off() is never called in atomic context.
> It calls mdelay() to busily wait, which is not necessary.
> mdelay() can be replaced with msleep().
> 
> This is found by a static analysis tool named DCNS written by myself.
> 
> Signed-off-by: Jia-Ju Bai <baijiaju1990@...il.com>
> ---
>  drivers/rtc/rtc-omap.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/rtc/rtc-omap.c b/drivers/rtc/rtc-omap.c
> index 39086398833e..ef3d09525d0f 100644
> --- a/drivers/rtc/rtc-omap.c
> +++ b/drivers/rtc/rtc-omap.c
> @@ -476,7 +476,7 @@ static void omap_rtc_power_off(void)
>  	 * power off the system. Add a 500 ms margin for external latencies
>  	 * (e.g. debounce circuits).
>  	 */
> -	mdelay(2500);
> +	msleep(2500);

I'm not sure about that one because this is a poweroff function so it
doesn't really make sense to sleep versus busy waiting (all the drivers
in power/reset use mdelay())


-- 
Alexandre Belloni, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com