linux-kernel - Re: [PATCH] rtc: pcf2127: add error checking and message when disabling POR0

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Message-ID: <Ygwo4iXtE/hCA5IZ@piout.net>
Date:   Tue, 15 Feb 2022 23:27:46 +0100
From:   Alexandre Belloni <alexandre.belloni@...tlin.com>
To:     Hugo Villeneuve <hugo@...ovil.com>
Cc:     Alessandro Zummo <a.zummo@...ertech.it>,
        Hugo Villeneuve <hvilleneuve@...onoff.com>,
        linux-rtc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] rtc: pcf2127: add error checking and message when
 disabling POR0

Hello,

On 17/01/2022 17:56:24-0500, Hugo Villeneuve wrote:
> From: Hugo Villeneuve <hvilleneuve@...onoff.com>
> 
> If PCF2127 device is absent from the I2C bus, or if there is a
> communication problem, disabling POR0 may fail silently and we
> still continue with probing the device. In that case, abort probe
> operation and display an error message.
> 
> Signed-off-by: Hugo Villeneuve <hvilleneuve@...onoff.com>
> ---
>  drivers/rtc/rtc-pcf2127.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/rtc/rtc-pcf2127.c b/drivers/rtc/rtc-pcf2127.c
> index 81a5b1f2e68c..e6d0838ccfe3 100644
> --- a/drivers/rtc/rtc-pcf2127.c
> +++ b/drivers/rtc/rtc-pcf2127.c
> @@ -690,8 +690,12 @@ static int pcf2127_probe(struct device *dev, struct regmap *regmap,
>  	 * The "Power-On Reset Override" facility prevents the RTC to do a reset
>  	 * after power on. For normal operation the PORO must be disabled.
>  	 */
> -	regmap_clear_bits(pcf2127->regmap, PCF2127_REG_CTRL1,
> +	ret = regmap_clear_bits(pcf2127->regmap, PCF2127_REG_CTRL1,
>  				PCF2127_BIT_CTRL1_POR_OVRD);
> +	if (ret < 0) {
> +		dev_err(dev, "PORO disabling failed\n");

As discussed on the other patches, please do not add a message here.


> +		return ret;
> +	}
>  
>  	ret = regmap_read(pcf2127->regmap, PCF2127_REG_CLKOUT, &val);
>  	if (ret < 0)
> -- 
> 2.30.2
> 

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