linux-kernel - Re: [PATCH 1/2] rtc-cmos: Clear expired alarm after resume

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Date:	Wed, 1 Jun 2016 18:11:17 +0200
From:	Gabriele Mazzotta <gabriele.mzt@...il.com>
To:	a.zummo@...ertech.it, alexandre.belloni@...e-electrons.com
Cc:	rtc-linux@...glegroups.com, linux-kernel@...r.kernel.org,
	matthew.garrett@...ula.com
Subject: Re: [PATCH 1/2] rtc-cmos: Clear expired alarm after resume

On 01/06/2016 17:40, Gabriele Mazzotta wrote:
> If the system wakes up because of a wake alarm, the internal state
> of the alarm is not updated. As consequence, the state no longer
> reflects the actual state of the hardware and setting a new alarm
> is not possible until the expired alarm is cleared.
> 
> Signed-off-by: Gabriele Mazzotta <gabriele.mzt@...il.com>
> ---
>  drivers/rtc/rtc-cmos.c | 22 ++++++++++++++++++++++
>  1 file changed, 22 insertions(+)
> 
> diff --git a/drivers/rtc/rtc-cmos.c b/drivers/rtc/rtc-cmos.c
> index fbe9c72..fd121e3 100644
> --- a/drivers/rtc/rtc-cmos.c
> +++ b/drivers/rtc/rtc-cmos.c
> @@ -900,11 +900,33 @@ static inline int cmos_poweroff(struct device *dev)
>  
>  #ifdef	CONFIG_PM_SLEEP
>  
> +static void cmos_check_alarm(struct device *dev)
> +{
> +	struct cmos_rtc *cmos = dev_get_drvdata(dev);
> +	struct rtc_wkalrm alarm;
> +	struct rtc_time now;
> +	time64_t t_now;
> +	time64_t t_expires;
> +
> +	cmos_read_time(dev, &now);
> +	rtc_read_alarm(cmos->rtc, &alarm);

Here it should probably check the return value and exit in case of error.

> +	t_now = rtc_tm_to_time64(&now);
> +	t_expires = rtc_tm_to_time64(&alarm.time);
> +
> +	if (t_expires <= t_now && alarm.enabled) {
> +		alarm.enabled = 0;
> +		cmos->suspend_ctrl &= ~RTC_AIE;
> +		rtc_set_alarm(cmos->rtc, &alarm);

Same here.

> +	}
> +}
> +
>  static int cmos_resume(struct device *dev)
>  {
>  	struct cmos_rtc	*cmos = dev_get_drvdata(dev);
>  	unsigned char tmp;
>  
> +	cmos_check_alarm(dev);
> +
>  	if (cmos->enabled_wake) {
>  		if (cmos->wake_off)
>  			cmos->wake_off(dev);
>