linux-kernel - Re: [PATCH] iio: adc: fsl-imx25-gcq: fix the right check andsimplify code

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Message-ID: <d1e08b62-37dd-b1e2-2cf5-baa03ccb16f2@cmss.chinamobile.com>
Date:   Mon, 2 Aug 2021 19:50:26 +0800
From:   tangbin <tangbin@...s.chinamobile.com>
To:     Jonathan Cameron <Jonathan.Cameron@...wei.com>
Cc:     Jonathan Cameron <jic23@...nel.org>, knaack.h@....de,
        lars@...afoo.de, shawnguo@...nel.org, s.hauer@...gutronix.de,
        festevam@...il.com, linux-iio@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] iio: adc: fsl-imx25-gcq: fix the right check andsimplify
 code

Hi Jonathan:

On 2021/8/2 18:16, Jonathan Cameron wrote:
> On Mon, 2 Aug 2021 10:31:58 +0800
> tangbin <tangbin@...s.chinamobile.com> wrote:
>
>> Hi Jonathan:
>>
>> On 2021/8/1 0:45, Jonathan Cameron wrote:
>>> On Tue, 27 Jul 2021 20:52:09 +0800
>>> Tang Bin <tangbin@...s.chinamobile.com> wrote:
>>>   
>>>> For the function of platform_get_irq(), the example in platform.c is
>>>> *		int irq = platform_get_irq(pdev, 0);
>>>> *		if (irq < 0)
>>>> *			return irq;
>>>> So the return value of zero is unnecessary to check. And move it
>>>> up to a little bit can simplify the code jump.
>>>>
>>>> Co-developed-by: Zhang Shengju <zhangshengju@...s.chinamobile.com>
>>>> Signed-off-by: Zhang Shengju <zhangshengju@...s.chinamobile.com>
>>>> Signed-off-by: Tang Bin <tangbin@...s.chinamobile.com>
>>> Hi,
>>>
>>> Logically it is better to keep the irq handling all together, so
>>> I would prefer we didn't move it.
>> Got it in this place.
>>> Also, platform_get_irq() is documented as never returning 0, so the current
>>> code is not incorrect.  As such, this looks like noise unless there is
>>> some plan to make use of the 0 return value?  What benefit do we get from
>>> this change?
>> Thanks for your reply, I think the benefit of this change maybe just
>> simplify the code.
>>
>> Because the return value is never equal to 0, so the check in here is
>> redundant.
>>
>> We can make the patch like this:
>>
>>>> ---
>>>>    drivers/iio/adc/fsl-imx25-gcq.c | 12 ++++--------
>>>>    1 file changed, 4 insertions(+), 8 deletions(-)
>>>>
>>>> diff --git a/drivers/iio/adc/fsl-imx25-gcq.c b/drivers/iio/adc/fsl-imx25-gcq.c
>>>> index 8cb51cf7a..d28976f21 100644
>>>> --- a/drivers/iio/adc/fsl-imx25-gcq.c
>>>> +++ b/drivers/iio/adc/fsl-imx25-gcq.c
>>>> @@ -320,6 +320,10 @@ static int mx25_gcq_probe(struct platform_device *pdev)
>>>>    	if (ret)
>>>>    		return ret;
>>>>    
>>>> +	priv->irq = platform_get_irq(pdev, 0);
>>>> +	if (priv->irq < 0)
>>>> +		return priv->irq;
>>>> +
>>>>    	for (i = 0; i != 4; ++i) {
>>>>    		if (!priv->vref[i])
>>>>    			continue;
>>>> @@ -336,14 +340,6 @@ static int mx25_gcq_probe(struct platform_device *pdev)
>>>>    		goto err_vref_disable;
>>>>    	}
>>>>    
>>>> -	priv->irq = platform_get_irq(pdev, 0);
>>>> -	if (priv->irq <= 0) {
>>>> -		ret = priv->irq;
>>>> -		if (!ret)
>>>> -			ret = -ENXIO;
>>>> -		goto err_clk_unprepare;
>>>> -	}
>>>> -
>> 	priv->irq = platform_get_irq(pdev, 0);
>> 	if (priv->irq < 0) {
>> 		ret = priv->irq;
>> 		goto err_clk_unprepare;
>> 	}
>>
>>       If you think this is ok, I will send V2 for you. If you think these
>> change is meaningless,
> OK, it's a minor tidy up, so lets go with that, or perhaps this is even tidier?
> Assuming types of ret and irq are appropriate (I've not checked!)
>
>
> 	ret = platform_get_irq(pdev, 0);
> 	if (ret)
> 		goto err_clk_unprepare;
>
> 	priv->irq = ret;
>
Thanks for your reply, ret or irq or priv->irq are all appropriate, and 
the changes of mine maybe traditional.

I will send v2 for you like your changes.

Thank you very much.

Tang Bin


>> just dropped this.
>>
>> Thanks
>>
>> Tang Bin
>>
>>
>>
>>