linux-kernel - Re: [PATCH v3] rtc: s3c: Don't print an error on probe deferral

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Message-ID: <56E77A6A.2090604@osg.samsung.com>
Date:	Mon, 14 Mar 2016 23:58:50 -0300
From:	Javier Martinez Canillas <javier@....samsung.com>
To:	Krzysztof Kozlowski <k.kozlowski@...sung.com>,
	linux-kernel@...r.kernel.org
Cc:	Joe Perches <joe@...ches.com>,
	Alexandre Belloni <alexandre.belloni@...e-electrons.com>,
	linux-samsung-soc@...r.kernel.org, rtc-linux@...glegroups.com
Subject: Re: [PATCH v3] rtc: s3c: Don't print an error on probe deferral

Hello Krzysztof,

On 03/14/2016 11:26 PM, Krzysztof Kozlowski wrote:
> On 15.03.2016 10:59, Javier Martinez Canillas wrote:
>>>>  
>>>>  	if (info->data->needs_src_clk) {
>>>>  		info->rtc_src_clk = devm_clk_get(&pdev->dev, "rtc_src");
>>>>  		if (IS_ERR(info->rtc_src_clk)) {
>>>> -			dev_err(&pdev->dev,
>>>> -				"failed to find rtc source clock\n");
>>>> +			ret = PTR_ERR(info->rtc_src_clk);
>>>> +			if (ret != -EPROBE_DEFER)
>>>> +				dev_err(&pdev->dev,
>>>> +					"failed to find rtc source clock\n");
>>>> +			else
>>>> +				dev_dbg(&pdev->dev,
>>>> +					"probe deferred due to missing rtc src clk\n");
>>>>  			clk_disable_unprepare(info->rtc_clk);
>>>> -			return PTR_ERR(info->rtc_src_clk);
>>>> +			return ret;
>>>>  		}
>>>>  		clk_prepare_enable(info->rtc_src_clk);
>>>>  	}
>>>>
>>>
>>> The error path starts looking complicated. This has now 4 indentation
>>> levels...
>>>
>>
>> Yeah, I don't think we can get rid of the 4 indentation levels since
>> the function already has 3 and a check for the errno code is needed.
> 
> Probably handling of the clocks in the driver could be simplified a
> little bit (the if(needs_src_clk) appears in few places)... but this is
> out of scope for this patch.
>

Agreed, I meant without introducing an unrelated change.
 
>>
>>> I agree for removal of error in case of probe deferral because it might
>>> be misleading but I don't see much benefit of a debug message.
>>>
>>
>> But yes, we can at least get rid of the else statement. I don't have a
>> strong opinion about the debug information, I left it to avoid someone
>> to tell me that I was removing a useful log.
> 
> Although dev_dbg doesn't harm... but isn't driver core printing debug
> message already?
>

I don't think it does or at least I didn't find it when looking
at the devm_clk_get() call chain.
 
> BR,
> Krzysztof
> 

Best regards,
-- 
Javier Martinez Canillas
Open Source Group
Samsung Research America