On 15.03.2016 10:59, Javier Martinez Canillas wrote:
> Hello Krzysztof,
>
> On 03/14/2016 10:50 PM, Krzysztof Kozlowski wrote:
>> On 15.03.2016 10:38, 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 a debug information.
>>>
>>> Signed-off-by: Javier Martinez Canillas <javier@xxxxxxxxxxxxxxx>
>>>
>>> ---
>>>
>>> Changes in v3:
>>> - Change debug messages again as suggested by Joe Perches.
>>>
>>> Changes in v2:
>>> - Improve debug messages as suggested by Joe Perches.
>>>
>>> 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..d01ad7e8078e 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 to missing rtc clk\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 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.
>
>> 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?
BR,
Krzysztof
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