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 11:34:05 +0200
From:   AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>
To:     Matthias Brugger <matthias.bgg@...il.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()

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?

Cheers,
Angelo