linux-kernel - Re: [PATCH v3 3/5] soc: mediatek: pwrap: Move and check return value of platform_get

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Date:   Tue, 17 May 2022 11:49:32 +0200
From:   Matthias Brugger <matthias.bgg@...il.com>
To:     AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>
Cc:     linux-arm-kernel@...ts.infradead.org,
        linux-mediatek@...ts.infradead.org, linux-kernel@...r.kernel.org,
        nfraprado@...labora.com, rex-bc.chen@...iatek.com,
        zhiyong.tao@...iatek.com
Subject: Re: [PATCH v3 3/5] soc: mediatek: pwrap: Move and check return value
 of platform_get_irq()



On 17/05/2022 11:34, AngeloGioacchino Del Regno wrote:
> Il 17/05/22 11:18, Matthias Brugger ha scritto:
>>
>>
>> On 16/05/2022 14:46, AngeloGioacchino Del Regno wrote:
>>> Move the call to platform_get_irq() earlier in the probe function
>>> and check for its return value: if no interrupt is specified, it
>>> wouldn't make sense to try to call devm_request_irq() so, in that
>>> case, we can simply return early.
>>>
>>> Moving the platform_get_irq() call also makes it possible to use
>>> one less goto, as clocks aren't required at that stage.
>>>
>>> Signed-off-by: AngeloGioacchino Del Regno 
>>> <angelogioacchino.delregno@...labora.com>
>>> Reviewed-by: Nícolas F. R. A. Prado <nfraprado@...labora.com>
>>> Tested-by: Nícolas F. R. A. Prado <nfraprado@...labora.com>
>>> ---
>>>   drivers/soc/mediatek/mtk-pmic-wrap.c | 5 ++++-
>>>   1 file changed, 4 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/soc/mediatek/mtk-pmic-wrap.c 
>>> b/drivers/soc/mediatek/mtk-pmic-wrap.c
>>> index 852514366f1f..332cbcabc299 100644
>>> --- a/drivers/soc/mediatek/mtk-pmic-wrap.c
>>> +++ b/drivers/soc/mediatek/mtk-pmic-wrap.c
>>> @@ -2204,6 +2204,10 @@ static int pwrap_probe(struct platform_device *pdev)
>>>       if (!wrp)
>>>           return -ENOMEM;
>>> +    irq = platform_get_irq(pdev, 0);
>>> +    if (irq < 0)
>>> +        return irq;
>>> +
>>>       platform_set_drvdata(pdev, wrp);
>>>       wrp->master = of_device_get_match_data(&pdev->dev);
>>> @@ -2316,7 +2320,6 @@ static int pwrap_probe(struct platform_device *pdev)
>>>       if (HAS_CAP(wrp->master->caps, PWRAP_CAP_INT1_EN))
>>>           pwrap_writel(wrp, wrp->master->int1_en_all, PWRAP_INT1_EN);
>>> -    irq = platform_get_irq(pdev, 0);
>>
>> For better readability of the code I'd prefer to keep platform_get_irq next to 
>> devm_request_irq. I understand that you did this change so that you don't have 
>> to code
>> if (irq < 0) {
>>      ret = irq;
>>      goto err_out2;
>> }
>>
>> Or do I miss something?
>>
> 
> That's for the sake of reducing gotos in the code... but there's a bigger
> picture that I haven't explained in this commit and that will come later
> because I currently don't have the necessary time to perform a "decent"
> testing.
> 
> As I was explaining - the bigger pictures implies adding a new function for
> clock teardown, that we will add as a devm action:
> 
> devm_add_action_or_reset(&pdev->dev, pwrap_clk_disable_unprepare, wrp)
> 
> ...so that we will be able to remove *all* gotos from the probe function.
> 
> Sounds good?
> 

Sounds good, but that means we could get rid of the goto as well. Anyway I 
prefer to have platform_get_irq next to devm_request_irq. If we can get rid of 
the goto in the future, great.

Regards,
Matthias