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

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Date:	Fri, 18 Mar 2016 08:57:57 -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 and Alexandre,

On 03/14/2016 11:58 PM, Javier Martinez Canillas wrote:
> 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
>>

Just to make sure that I understood correctly, there's no action I
should take in order for this patch to be picked right? IOW, the
current version is OK?

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