linux-kernel - Re: [PATCH] drivers: rtc: rv3028: check and update PORF flag during probe

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Message-ID: <20240329102847fcdca1cf@mail.local>
Date: Fri, 29 Mar 2024 11:28:47 +0100
From: Alexandre Belloni <alexandre.belloni@...tlin.com>
To: Karthikeyan Krishnasamy <karthikeyan@...umiz.com>
Cc: linux-rtc@...r.kernel.org, linux-kernel@...r.kernel.org,
	parthiban@...umiz.com, saravanan@...umiz.com
Subject: Re: [PATCH] drivers: rtc: rv3028: check and update PORF flag during
 probe

On 29/03/2024 15:49:40+0530, Karthikeyan Krishnasamy wrote:
> PORF flag is set during power reset and voltage drop below Vpor
> data in rtc device is no longer valid if PORF flag is set
> and software must reset to 0, in order to perform sanity
> check on rtc data
> 
> Signed-off-by: Karthikeyan Krishnasamy <karthikeyan@...umiz.com>
> ---
>  drivers/rtc/rtc-rv3028.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/drivers/rtc/rtc-rv3028.c b/drivers/rtc/rtc-rv3028.c
> index 2f001c59c61d..e9699ff0c4e8 100644
> --- a/drivers/rtc/rtc-rv3028.c
> +++ b/drivers/rtc/rtc-rv3028.c
> @@ -951,6 +951,13 @@ static int rv3028_probe(struct i2c_client *client)
>  	if (ret < 0)
>  		return ret;
>  
> +	if (status & RV3028_STATUS_PORF) {
> +		ret = regmap_update_bits(rv3028->regmap, RV3028_STATUS,
> +					 RV3028_STATUS_PORF, 0);
> +		if (ret < 0)
> +			return ret;
> +	}
> +

This breaks the workflow, you must set the time to reset PORF.

>  	if (status & RV3028_STATUS_AF)
>  		dev_warn(&client->dev, "An alarm may have been missed.\n");
>  
> -- 
> 2.34.1
> 

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