linux-kernel - Re: [PATCH 06/13] media: davinci: vpif: Use platform_get_irq

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Message-ID: <CA+V-a8snJU6YYtfcN_mWCJGxYnbNGrLdU+Y5g06mjV4dhsABMw@mail.gmail.com>
Date:   Tue, 4 Jan 2022 17:22:52 +0000
From:   "Lad, Prabhakar" <prabhakar.csengg@...il.com>
To:     Andy Shevchenko <andy.shevchenko@...il.com>
Cc:     Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>,
        Linux Media Mailing List <linux-media@...r.kernel.org>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Hans Verkuil <hverkuil-cisco@...all.nl>,
        Rob Herring <robh+dt@...nel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Linux-Renesas <linux-renesas-soc@...r.kernel.org>
Subject: Re: [PATCH 06/13] media: davinci: vpif: Use platform_get_irq_optional()
 to get the interrupt

Hi Andy,

Thank you for the review.

On Sat, Dec 25, 2021 at 5:32 PM Andy Shevchenko
<andy.shevchenko@...il.com> wrote:
>
> On Sat, Dec 25, 2021 at 3:04 AM Lad Prabhakar
> <prabhakar.mahadev-lad.rj@...renesas.com> 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_optional().
> >
> > Also this patch propagates error code in case devm_request_irq()
> > fails instead of returing -EINVAL.
>
> returning
>
> ...
>
> > +       res_irq->flags = IORESOURCE_IRQ | irq_get_trigger_type(irq);
> > +       res_irq->start = irq;
> > +       res_irq->end = irq;
> > +       res_irq->name = dev_of_node(&pdev->dev) ? of_node_full_name(pdev->dev.of_node) : NULL;
>
> If you convert DEFINE_RES_NAMED() to return a compound literal, then
> you may use it here like
>
> res_irq = DEFINE_RES_NAMED(...);
>
> or even do like this
>
> if (dev_of_node(...))
>   res_irq = DEFINE_RES_IRQ_NAMED(...)
> else
>   res_irq = DEFINE_RES_IRQ(...);
> res_irq->flags |= irq_get_trigger_type(irq);
>
There are quite a few users of DEFINE_RES_IRQ_NAMED()/DEFINE_RES_IRQ()
changing this macos just for this single user tree wide doesn't make
sense. Let me know if you think otherwise.

> I'm not sure why you can't simply use the NAMED variant in both cases
> (yes, I see that of_node_full_name() will return something, not NULL).
>
> ...
>
> > +       while ((err = platform_get_irq_optional(pdev, res_idx)) != -ENXIO) {
> > +               if (err < 0)
> > +                       goto vpif_unregister;
>
> Needs a better error checking, i.e. consider 0 as no-IRQ (equivalent
> to -ENXIO (note, OF code never returns 0 as valid vIRQ).
>
Will fix that.

> >                 res_idx++;
> >         }
>
> ...
>
> > +       while ((err = platform_get_irq_optional(pdev, res_idx)) != -ENXIO) {
> > +               if (err < 0)
> > +                       goto vpif_unregister;
>
> Ditto.
>
Will fix that.

Cheers,
Prabhakar