linux-kernel - Re: [PATCH] rtc: stmp3xxx: check for failure

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Message-ID: <20160415210715.GF25196@piout.net>
Date:	Fri, 15 Apr 2016 23:07:15 +0200
From:	Alexandre Belloni <alexandre.belloni@...e-electrons.com>
To:	Sudip Mukherjee <sudipm.mukherjee@...il.com>
Cc:	Alessandro Zummo <a.zummo@...ertech.it>,
	linux-kernel@...r.kernel.org, rtc-linux@...glegroups.com
Subject: Re: [PATCH] rtc: stmp3xxx: check for failure

Hi,

On 11/04/2016 at 22:03:55 +0530, Sudip Mukherjee wrote :
> stmp3xxx_wdt_register() can fail as platform_device_alloc() or
> platform_device_add() can fail. Lets check for the return value from
> both platform_device_alloc() and platform_device_add() and return the
> error value accordingly which is now propagated from probe.
> 

Well, this may have been intentional. The RTC doesn't need the watchdog
driver to be present to work correctly. However, I agree that failing
silently is not nice.

Did you have any particular issue? Maybe simply adding a dev_err() or
two would be fine.

> Signed-off-by: Sudip Mukherjee <sudip.mukherjee@...ethink.co.uk>
> ---
>  drivers/rtc/rtc-stmp3xxx.c | 19 ++++++++++---------
>  1 file changed, 10 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/rtc/rtc-stmp3xxx.c b/drivers/rtc/rtc-stmp3xxx.c
> index ca54d03..e02e827 100644
> --- a/drivers/rtc/rtc-stmp3xxx.c
> +++ b/drivers/rtc/rtc-stmp3xxx.c
> @@ -105,20 +105,22 @@ static struct stmp3xxx_wdt_pdata wdt_pdata = {
>  	.wdt_set_timeout = stmp3xxx_wdt_set_timeout,
>  };
>  
> -static void stmp3xxx_wdt_register(struct platform_device *rtc_pdev)
> +static int stmp3xxx_wdt_register(struct platform_device *rtc_pdev)
>  {
>  	struct platform_device *wdt_pdev =
>  		platform_device_alloc("stmp3xxx_rtc_wdt", rtc_pdev->id);
>  
> -	if (wdt_pdev) {
> -		wdt_pdev->dev.parent = &rtc_pdev->dev;
> -		wdt_pdev->dev.platform_data = &wdt_pdata;
> -		platform_device_add(wdt_pdev);
> -	}
> +	if (!wdt_pdev)
> +		return -ENOMEM;
> +
> +	wdt_pdev->dev.parent = &rtc_pdev->dev;
> +	wdt_pdev->dev.platform_data = &wdt_pdata;
> +	return platform_device_add(wdt_pdev);
>  }
>  #else
> -static void stmp3xxx_wdt_register(struct platform_device *rtc_pdev)
> +static int stmp3xxx_wdt_register(struct platform_device *rtc_pdev)
>  {
> +	return 0;
>  }
>  #endif /* CONFIG_STMP3XXX_RTC_WATCHDOG */
>  
> @@ -357,8 +359,7 @@ static int stmp3xxx_rtc_probe(struct platform_device *pdev)
>  		return err;
>  	}
>  
> -	stmp3xxx_wdt_register(pdev);
> -	return 0;
> +	return stmp3xxx_wdt_register(pdev);
>  }
>  
>  #ifdef CONFIG_PM_SLEEP
> -- 
> 1.9.1
> 

-- 
Alexandre Belloni, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com