linux-kernel - Re: [PATCH v2 2/3] dmaengine: mediatek: mtk-hsdma: Use platform_get

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Date:   Thu, 6 Jan 2022 08:44:25 +0000
From:   "Lad, Prabhakar" <prabhakar.csengg@...il.com>
To:     Vinod Koul <vkoul@...nel.org>
Cc:     Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>,
        Sean Wang <sean.wang@...iatek.com>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Rob Herring <robh+dt@...nel.org>,
        Andy Shevchenko <andy.shevchenko@...il.com>,
        dmaengine <dmaengine@...r.kernel.org>,
        LAK <linux-arm-kernel@...ts.infradead.org>,
        "moderated list:ARM/Mediatek SoC support" 
        <linux-mediatek@...ts.infradead.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 2/3] dmaengine: mediatek: mtk-hsdma: Use
 platform_get_irq() to get the interrupt

Hi Vinod,

Thank you for the review.

On Thu, Jan 6, 2022 at 5:27 AM Vinod Koul <vkoul@...nel.org> wrote:
>
> On 04-01-22, 16:35, Lad Prabhakar wrote:
> > platform_get_resource(pdev, IORESOURCE_IRQ, ..) relies on static
> > allocation of IRQ resources in DT core code, this causes an issue
> > when using hierarchical interrupt domains using "interrupts" property
> > in the node as this bypasses the hierarchical setup and messes up the
> > irq chaining.
> >
> > In preparation for removal of static setup of IRQ resource from DT core
> > code use platform_get_irq().
> >
> > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
> > ---
> > v1->v2
> > * No change
> > ---
> >  drivers/dma/mediatek/mtk-hsdma.c | 11 ++++-------
> >  1 file changed, 4 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/dma/mediatek/mtk-hsdma.c b/drivers/dma/mediatek/mtk-hsdma.c
> > index 6ad8afbb95f2..c0fffde7fe08 100644
> > --- a/drivers/dma/mediatek/mtk-hsdma.c
> > +++ b/drivers/dma/mediatek/mtk-hsdma.c
> > @@ -923,13 +923,10 @@ static int mtk_hsdma_probe(struct platform_device *pdev)
> >               return PTR_ERR(hsdma->clk);
> >       }
> >
> > -     res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
> > -     if (!res) {
> > -             dev_err(&pdev->dev, "No irq resource for %s\n",
> > -                     dev_name(&pdev->dev));
> > -             return -EINVAL;
> > -     }
> > -     hsdma->irq = res->start;
> > +     err = platform_get_irq(pdev, 0);
>
> why not platform_get_irq_optional() here and 3rd patch ?
>
For patches #2 and #3 the driver expects the IRQ to be present
strictly, that is the reason platform_get_irq_optional() isn't used so
that the behavior of the driver is unchanged with this patch.

Cheers,
Prabhakar

> > +     if (err < 0)
> > +             return err;
> > +     hsdma->irq = err;
> >
> >       refcount_set(&hsdma->pc_refcnt, 0);
> >       spin_lock_init(&hsdma->lock);
> > --
> > 2.17.1
>
> --
> ~Vinod