linux-kernel - Re: [PATCH 11/29] rtc: pcf2127: set RTC_FEATURE_ALARM_RES

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Message-Id: <20220310110918.41a681474f5a0e11abdedc39@hugovil.com>
Date:   Thu, 10 Mar 2022 11:09:18 -0500
From:   Hugo Villeneuve <hugo@...ovil.com>
To:     Alexandre Belloni <alexandre.belloni@...tlin.com>
Cc:     Alessandro Zummo <a.zummo@...ertech.it>, linux-rtc@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 11/29] rtc: pcf2127: set RTC_FEATURE_ALARM_RES_2S

On Wed,  9 Mar 2022 17:22:42 +0100
Alexandre Belloni <alexandre.belloni@...tlin.com> wrote:

> The PCF2127 doesn't support UIE because setting an alarm to fire every
> second confuses the chip and the fastest we can go is an alarm every 2
> seconds.

Hi Alexandre,
can you describe what "confuses the chip" means?

In my experimental PCF2131 driver, I activated UIE and it seems to be working fine at 1s intervals, but since it is similar to PCF2127, maybe there is still a problem and I just didn't see it.

Hugo.


> Signed-off-by: Alexandre Belloni <alexandre.belloni@...tlin.com>
> ---
>  drivers/rtc/rtc-pcf2127.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/rtc/rtc-pcf2127.c b/drivers/rtc/rtc-pcf2127.c
> index f8469b134411..63b275b014bd 100644
> --- a/drivers/rtc/rtc-pcf2127.c
> +++ b/drivers/rtc/rtc-pcf2127.c
> @@ -656,6 +656,7 @@ static int pcf2127_probe(struct device *dev, struct regmap *regmap,
>  	pcf2127->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
>  	pcf2127->rtc->range_max = RTC_TIMESTAMP_END_2099;
>  	pcf2127->rtc->set_start_time = true; /* Sets actual start to 1970 */
> +	set_bit(RTC_FEATURE_ALARM_RES_2S, pcf2127->rtc->features);
>  	clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, pcf2127->rtc->features);
>  	clear_bit(RTC_FEATURE_ALARM, pcf2127->rtc->features);
>  
> -- 
> 2.35.1
> 


-- 
Hugo Villeneuve <hugo@...ovil.com>