linux-kernel - Re: [PATCH] media: hantro: Fix check for single irq

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Message-ID: <1909651.VgzLf9ffF6@jernej-laptop>
Date:   Fri, 06 Aug 2021 17:39:47 +0200
From:   Jernej Škrabec <jernej.skrabec@...il.com>
To:     p.zabel@...gutronix.de, Ezequiel Garcia <ezequiel@...labora.com>
Cc:     mchehab@...nel.org, gregkh@...uxfoundation.org,
        hverkuil-cisco@...all.nl, emil.velikov@...labora.com,
        linux-media@...r.kernel.org, linux-rockchip@...ts.infradead.org,
        linux-staging@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] media: hantro: Fix check for single irq

Dne petek, 06. avgust 2021 ob 16:13:46 CEST je Ezequiel Garcia napisal(a):
> On Fri, 2021-08-06 at 06:44 +0200, Jernej Škrabec wrote:
> > Dne petek, 06. avgust 2021 ob 00:03:36 CEST je Ezequiel Garcia napisal(a):
> > > Hi Jernej,
> > > 
> > > On Thu, 2021-08-05 at 21:04 +0200, Jernej Skrabec wrote:
> > > > Some cores use only one interrupt and in such case interrupt name in
> > > > DT
> > > > is not needed. Driver supposedly accounted that, but due to the wrong
> > > > field check it never worked. Fix that.
> > > > 
> > > > Fixes: 18d6c8b7b4c9 ("media: hantro: add fallback handling for single
> > > > irq/clk") Signed-off-by: Jernej Skrabec <jernej.skrabec@...il.com>
> > > > ---
> > > >  drivers/staging/media/hantro/hantro_drv.c | 2 +-
> > > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > > 
> > > > diff --git a/drivers/staging/media/hantro/hantro_drv.c
> > > > b/drivers/staging/media/hantro/hantro_drv.c index
> > > > 8a2edd67f2c6..20e508158871 100644
> > > > --- a/drivers/staging/media/hantro/hantro_drv.c
> > > > +++ b/drivers/staging/media/hantro/hantro_drv.c
> > > > @@ -919,7 +919,7 @@ static int hantro_probe(struct platform_device
> > > > *pdev)
> > > >                 if (!vpu->variant->irqs[i].handler)
> > > >                         continue;
> > > >  
> > > > -               if (vpu->variant->num_clocks > 1) {
> > > > +               if (vpu->variant->num_irqs > 1) {
> > > 
> > > Oops, thanks for spotting this.
> > > 
> > > How about this instead?
> > 
> > No, original solution is more robust. With solution below, you're assuming
> > that irq order in driver array is same as in DT. That doesn't matter if
> > there is only one name or if names match. However, if there is a typo,
> > either in DT node or in driver, driver will still happily assign clock
> > based on index and that might not be correct one. Even if it works out,
> > you can easily miss that you have a typo. Driver doesn't tell you which
> > irq is used, if it is successfully acquired.
> 
> I find it odd to iterate up to num_irqs but then
> have a case for num_irqs == 1, and call
> platform_get_irq(vpu->pdev, 0).

True, it was also strange for me at first, but then it's robust and simple. 
Because of that, I just fixed obvious issue.

> 
> But OTOH, your fix is correct and it's a oneliner.
> 
> Reviewed-by: Ezequiel Garcia <ezequiel@...labora.com>
> 

Thanks!

Best regards,
Jernej

> Thanks,
> Ezequiel