[PATCH] rtc: s3c: Don't print an error on probe deferral

[PATCH] rtc: s3c: Don't print an error on probe deferral

[Javier Martinez Canillas]

The clock and source clock looked up by the driver may not be available
just because the clock controller driver was not probed yet so printing
an error in this case is not correct and only adds confusion to users.

However, knowing that a driver's probe was deferred may be useful so it
can be printed as debug information.

Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>

---

 drivers/rtc/rtc-s3c.c | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/drivers/rtc/rtc-s3c.c b/drivers/rtc/rtc-s3c.c
index ffb860d18701..789ac8715038 100644
--- a/drivers/rtc/rtc-s3c.c
+++ b/drivers/rtc/rtc-s3c.c
@@ -501,18 +501,27 @@ static int s3c_rtc_probe(struct platform_device *pdev)
 
 	info->rtc_clk = devm_clk_get(&pdev->dev, "rtc");
 	if (IS_ERR(info->rtc_clk)) {
-		dev_err(&pdev->dev, "failed to find rtc clock\n");
-		return PTR_ERR(info->rtc_clk);
+		ret = PTR_ERR(info->rtc_clk);
+		if (ret != -EPROBE_DEFER)
+			dev_err(&pdev->dev, "failed to find rtc clock\n");
+		else
+			dev_dbg(&pdev->dev, "probe deferred due rtc clock\n");
+		return ret;
 	}
 	clk_prepare_enable(info->rtc_clk);
 
 	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 rtc source clock\n");
 			clk_disable_unprepare(info->rtc_clk);
-			return PTR_ERR(info->rtc_src_clk);
+			return ret;
 		}
 		clk_prepare_enable(info->rtc_src_clk);
 	}
-- 
2.5.0

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

[Joe Perches]

On Mon, 2016-03-14 at 16:05 -0300, Javier Martinez Canillas wrote:
> The clock and source clock looked up by the driver may not be available
> just because the clock controller driver was not probed yet so printing
> an error in this case is not correct and only adds confusion to users.
> 
> However, knowing that a driver's probe was deferred may be useful so it
> can be printed as debug information.
[]
> diff --git a/drivers/rtc/rtc-s3c.c b/drivers/rtc/rtc-s3c.c
[]
> @@ -501,18 +501,27 @@ static int s3c_rtc_probe(struct platform_device *pdev)
>  
>  	info->rtc_clk = devm_clk_get(&pdev->dev, "rtc");
>  	if (IS_ERR(info->rtc_clk)) {
> -		dev_err(&pdev->dev, "failed to find rtc clock\n");
> -		return PTR_ERR(info->rtc_clk);
> +		ret = PTR_ERR(info->rtc_clk);
> +		if (ret != -EPROBE_DEFER)
> +			dev_err(&pdev->dev, "failed to find rtc clock\n");
> +		else
> +			dev_dbg(&pdev->dev, "probe deferred due rtc clock\n");
> +		return ret;
>  	}
>  	clk_prepare_enable(info->rtc_clk);
>  
>  	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 rtc source clock\n");
>  			clk_disable_unprepare(info->rtc_clk);
> -			return PTR_ERR(info->rtc_src_clk);
> +			return ret;
>  		}
>  		clk_prepare_enable(info->rtc_src_clk);
>  	}

Maybe the debug logging messages could be object->action like:

	rtc clock probe deferred
	rtc source clock probe deferred

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

[Javier Martinez Canillas]

Hello Joe,

Thanks a lot for your feedback.

On 03/14/2016 04:11 PM, Joe Perches wrote:
> On Mon, 2016-03-14 at 16:05 -0300, Javier Martinez Canillas wrote:
>> The clock and source clock looked up by the driver may not be available
>> just because the clock controller driver was not probed yet so printing
>> an error in this case is not correct and only adds confusion to users.
>>
>> However, knowing that a driver's probe was deferred may be useful so it
>> can be printed as debug information.
> []
>> diff --git a/drivers/rtc/rtc-s3c.c b/drivers/rtc/rtc-s3c.c
> []
>> @@ -501,18 +501,27 @@ static int s3c_rtc_probe(struct platform_device *pdev)
>>  
>>  	info->rtc_clk = devm_clk_get(&pdev->dev, "rtc");
>>  	if (IS_ERR(info->rtc_clk)) {
>> -		dev_err(&pdev->dev, "failed to find rtc clock\n");
>> -		return PTR_ERR(info->rtc_clk);
>> +		ret = PTR_ERR(info->rtc_clk);
>> +		if (ret != -EPROBE_DEFER)
>> +			dev_err(&pdev->dev, "failed to find rtc clock\n");
>> +		else
>> +			dev_dbg(&pdev->dev, "probe deferred due rtc clock\n");
>> +		return ret;
>>  	}
>>  	clk_prepare_enable(info->rtc_clk);
>>  
>>  	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 rtc source clock\n");
>>  			clk_disable_unprepare(info->rtc_clk);
>> -			return PTR_ERR(info->rtc_src_clk);
>> +			return ret;
>>  		}
>>  		clk_prepare_enable(info->rtc_src_clk);
>>  	}
> 
> Maybe the debug logging messages could be object->action like:
> 
> 	rtc clock probe deferred
> 	rtc source clock probe deferred
> 

I found your suggested messages harder to read and more confusing. The
action that happens is a probe function deferral and that is caused by
a missing resource needed by the driver (clocks in this case).

But your messages seems to imply that the probe deferred action happens
to a clock, it sounds like "rtc clock disabled" and that's not correct.

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

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

[Joe Perches]

On Mon, 2016-03-14 at 16:31 -0300, Javier Martinez Canillas wrote:
> On 03/14/2016 04:11 PM, Joe Perches wrote:> > On Mon, 2016-03-14 at 16:05 -0300, Javier Martinez Canillas wrote:
> > > 
> > > The clock and source clock looked up by the driver may not be available
> > > just because the clock controller driver was not probed yet so printing
> > > an error in this case is not correct and only adds confusion to users.
> > > 
> > > However, knowing that a driver's probe was deferred may be useful so it
> > > can be printed as debug information.
> > []
> > > 
> > > diff --git a/drivers/rtc/rtc-s3c.c b/drivers/rtc/rtc-s3c.c
> > []
> > > 
> > > @@ -501,18 +501,27 @@ static int s3c_rtc_probe(struct platform_device *pdev)
> > >  
> > >  	info->rtc_clk = devm_clk_get(&pdev->dev, "rtc");
> > >  	if (IS_ERR(info->rtc_clk)) {
> > > -		dev_err(&pdev->dev, "failed to find rtc clock\n");
> > > -		return PTR_ERR(info->rtc_clk);
> > > +		ret = PTR_ERR(info->rtc_clk);
> > > +		if (ret != -EPROBE_DEFER)
> > > +			dev_err(&pdev->dev, "failed to find rtc clock\n");
> > > +		else
> > > +			dev_dbg(&pdev->dev, "probe deferred due rtc clock\n");
> > > +		return ret;
> > >  	}
> > >  	clk_prepare_enable(info->rtc_clk);
> > >  
> > >  	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 rtc source clock\n");
> > >  			clk_disable_unprepare(info->rtc_clk);
> > > -			return PTR_ERR(info->rtc_src_clk);
> > > +			return ret;
> > >  		}
> > >  		clk_prepare_enable(info->rtc_src_clk);
> > >  	}
> > Maybe the debug logging messages could be object->action like:
> > 
> > 	rtc clock probe deferred
> > 	rtc source clock probe deferred
> > 
> I found your suggested messages harder to read and more confusing. The
> action that happens is a probe function deferral and that is caused by
> a missing resource needed by the driver (clocks in this case).
> 
> But your messages seems to imply that the probe deferred action happens
> to a clock, it sounds like "rtc clock disabled" and that's not correct.

OK, then please change "due" to "due to" or "for" in your messages
because they make little sense now.

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

[Javier Martinez Canillas]

Hello Joe,

On 03/14/2016 04:38 PM, Joe Perches wrote:
> On Mon, 2016-03-14 at 16:31 -0300, Javier Martinez Canillas wrote:
>> On 03/14/2016 04:11 PM, Joe Perches wrote:> > On Mon, 2016-03-14 at 16:05 -0300, Javier Martinez Canillas wrote:
>>>>
>>>> The clock and source clock looked up by the driver may not be available
>>>> just because the clock controller driver was not probed yet so printing
>>>> an error in this case is not correct and only adds confusion to users.
>>>>
>>>> However, knowing that a driver's probe was deferred may be useful so it
>>>> can be printed as debug information.
>>> []
>>>>
>>>> diff --git a/drivers/rtc/rtc-s3c.c b/drivers/rtc/rtc-s3c.c
>>> []
>>>>
>>>> @@ -501,18 +501,27 @@ static int s3c_rtc_probe(struct platform_device *pdev)
>>>>  
>>>>  	info->rtc_clk = devm_clk_get(&pdev->dev, "rtc");
>>>>  	if (IS_ERR(info->rtc_clk)) {
>>>> -		dev_err(&pdev->dev, "failed to find rtc clock\n");
>>>> -		return PTR_ERR(info->rtc_clk);
>>>> +		ret = PTR_ERR(info->rtc_clk);
>>>> +		if (ret != -EPROBE_DEFER)
>>>> +			dev_err(&pdev->dev, "failed to find rtc clock\n");
>>>> +		else
>>>> +			dev_dbg(&pdev->dev, "probe deferred due rtc clock\n");
>>>> +		return ret;
>>>>  	}
>>>>  	clk_prepare_enable(info->rtc_clk);
>>>>  
>>>>  	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 rtc source clock\n");
>>>>  			clk_disable_unprepare(info->rtc_clk);
>>>> -			return PTR_ERR(info->rtc_src_clk);
>>>> +			return ret;
>>>>  		}
>>>>  		clk_prepare_enable(info->rtc_src_clk);
>>>>  	}
>>> Maybe the debug logging messages could be object->action like:
>>>
>>> 	rtc clock probe deferred
>>> 	rtc source clock probe deferred
>>>
>> I found your suggested messages harder to read and more confusing. The
>> action that happens is a probe function deferral and that is caused by
>> a missing resource needed by the driver (clocks in this case).
>>
>> But your messages seems to imply that the probe deferred action happens
>> to a clock, it sounds like "rtc clock disabled" and that's not correct.
> 
> OK, then please change "due" to "due to" or "for" in your messages
> because they make little sense now.
>

I don't think they make little sense now since even a non-native english
speaker like me can understand it :)

But yes, it's cryptic at the very least. That's the problem with long text
and the 80 char limit to make checkpatch.pl happy. I guess I can just move
the message a little bit even if that will make to not be properly aligned.

I'll wait a couple of days to see if there's any other feedback and repost.

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

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

[Joe Perches]

On Mon, 2016-03-14 at 16:59 -0300, Javier Martinez Canillas wrote:
> I don't think they make little sense now since even a non-native english
> speaker like me can understand it :)

That's a non sequitur if ever I read one.

> But yes, it's cryptic at the very least. That's the problem with long text
> and the 80 char limit to make checkpatch.pl happy. I guess I can just move
> the message a little bit even if that will make to not be properly aligned.

There's no issue with longer than 80 column lines
for these messages.  checkpatch wouldn't complain.

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

[Javier Martinez Canillas]

Hello Joe,

On 03/14/2016 05:03 PM, Joe Perches wrote:
> On Mon, 2016-03-14 at 16:59 -0300, Javier Martinez Canillas wrote:
>> I don't think they make little sense now since even a non-native english
>> speaker like me can understand it :)
> 
> That's a non sequitur if ever I read one.
>

I was trying to be funny but it seems that I failed.
 
>> But yes, it's cryptic at the very least. That's the problem with long text
>> and the 80 char limit to make checkpatch.pl happy. I guess I can just move
>> the message a little bit even if that will make to not be properly aligned.
> 
> There's no issue with longer than 80 column lines
> for these messages.  checkpatch wouldn't complain.
> 

Great, I didn't know that checkpatch had an exception for the 80 column
rule. I'll post a v2 then.

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

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

[Alexandre Belloni]

On 14/03/2016 at 16:59:33 -0300, Javier Martinez Canillas wrote :
> Hello Joe,
> 
> On 03/14/2016 04:38 PM, Joe Perches wrote:
> > On Mon, 2016-03-14 at 16:31 -0300, Javier Martinez Canillas wrote:
> >> On 03/14/2016 04:11 PM, Joe Perches wrote:> > On Mon, 2016-03-14 at 16:05 -0300, Javier Martinez Canillas wrote:
> >>>>
> >>>> The clock and source clock looked up by the driver may not be available
> >>>> just because the clock controller driver was not probed yet so printing
> >>>> an error in this case is not correct and only adds confusion to users.
> >>>>
> >>>> However, knowing that a driver's probe was deferred may be useful so it
> >>>> can be printed as debug information.
> >>> []
> >>>>
> >>>> diff --git a/drivers/rtc/rtc-s3c.c b/drivers/rtc/rtc-s3c.c
> >>> []
> >>>>
> >>>> @@ -501,18 +501,27 @@ static int s3c_rtc_probe(struct platform_device *pdev)
> >>>>  
> >>>>  	info->rtc_clk = devm_clk_get(&pdev->dev, "rtc");
> >>>>  	if (IS_ERR(info->rtc_clk)) {
> >>>> -		dev_err(&pdev->dev, "failed to find rtc clock\n");
> >>>> -		return PTR_ERR(info->rtc_clk);
> >>>> +		ret = PTR_ERR(info->rtc_clk);
> >>>> +		if (ret != -EPROBE_DEFER)
> >>>> +			dev_err(&pdev->dev, "failed to find rtc clock\n");
> >>>> +		else
> >>>> +			dev_dbg(&pdev->dev, "probe deferred due rtc clock\n");
> >>>> +		return ret;
> >>>>  	}
> >>>>  	clk_prepare_enable(info->rtc_clk);
> >>>>  
> >>>>  	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 rtc source clock\n");
> >>>>  			clk_disable_unprepare(info->rtc_clk);
> >>>> -			return PTR_ERR(info->rtc_src_clk);
> >>>> +			return ret;
> >>>>  		}
> >>>>  		clk_prepare_enable(info->rtc_src_clk);
> >>>>  	}
> >>> Maybe the debug logging messages could be object->action like:
> >>>
> >>> 	rtc clock probe deferred
> >>> 	rtc source clock probe deferred
> >>>
> >> I found your suggested messages harder to read and more confusing. The
> >> action that happens is a probe function deferral and that is caused by
> >> a missing resource needed by the driver (clocks in this case).
> >>
> >> But your messages seems to imply that the probe deferred action happens
> >> to a clock, it sounds like "rtc clock disabled" and that's not correct.
> > 
> > OK, then please change "due" to "due to" or "for" in your messages
> > because they make little sense now.
> >
> 
> I don't think they make little sense now since even a non-native english
> speaker like me can understand it :)
> 
> But yes, it's cryptic at the very least. That's the problem with long text
> and the 80 char limit to make checkpatch.pl happy. I guess I can just move
> the message a little bit even if that will make to not be properly aligned.
> 

checkpatch will not complain for messages but it will definitively
complain if they are not properly aligned:)


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

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

[Joe Perches]

On Mon, 2016-03-14 at 21:19 +0100, Alexandre Belloni wrote:
> checkpatch will not complain for messages but it will definitively
> complain if they are not properly aligned:)

checkpatch wouldn't actually complain unless the --strict option
was used or these files were in drivers/net or drivers/staging.

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

[Alexandre Belloni]

On 14/03/2016 at 13:33:08 -0700, Joe Perches wrote :
> On Mon, 2016-03-14 at 21:19 +0100, Alexandre Belloni wrote:
> > checkpatch will not complain for messages but it will definitively
> > complain if they are not properly aligned:)
> 
> checkpatch wouldn't actually complain unless the --strict option
> was used or these files were in drivers/net or drivers/staging.
> 

yeah, I'm using --strict on all the patches I receive.

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