linux-kernel - Re: [PATCH] rtc: snvs: Handle error for clk

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Message-ID: <YieFovazuZ7tgeyj@piout.net>
Date:   Tue, 8 Mar 2022 17:34:42 +0100
From:   Alexandre Belloni <alexandre.belloni@...tlin.com>
To:     Jiasheng Jiang <jiasheng@...as.ac.cn>
Cc:     a.zummo@...ertech.it, linux-rtc@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] rtc: snvs: Handle error for clk_enable

On 04/03/2022 15:20:18+0800, Jiasheng Jiang wrote:
> As the potential failure of the clk_enable(),
> it should be better to check it and return error
> if fails.
> 
> Fixes: edb190cb1734 ("rtc: snvs: make sure clock is enabled for interrupt handle")
> Signed-off-by: Jiasheng Jiang <jiasheng@...as.ac.cn>
> ---
>  drivers/rtc/rtc-snvs.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/rtc/rtc-snvs.c b/drivers/rtc/rtc-snvs.c
> index bd929b0e7d7d..f273f7d873f8 100644
> --- a/drivers/rtc/rtc-snvs.c
> +++ b/drivers/rtc/rtc-snvs.c
> @@ -269,8 +269,11 @@ static irqreturn_t snvs_rtc_irq_handler(int irq, void *dev_id)
>  	struct snvs_rtc_data *data = dev_get_drvdata(dev);
>  	u32 lpsr;
>  	u32 events = 0;
> +	int ret;
>  
> -	clk_enable(data->clk);
> +	ret = clk_enable(data->clk);
> +	if (ret)
> +		return IRQ_NONE;

I don't think you thought about the implication here, if this happens,
then the interrupt will be considered spurious which is definitively not
something we want.

>  
>  	regmap_read(data->regmap, data->offset + SNVS_LPSR, &lpsr);
>  
> -- 
> 2.25.1
> 

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