linux-kernel - Re: [PATCH v12 3/6] PCI: mediatek: Add new method to get irq number

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Message-ID: <93f44e07917e6e194fdf62bee98f7041e9f2d546.camel@mediatek.com>
Date:   Thu, 2 Sep 2021 17:28:44 +0800
From:   Chuanjia Liu <chuanjia.liu@...iatek.com>
To:     Bjorn Helgaas <helgaas@...nel.org>
CC:     <robh+dt@...nel.org>, <bhelgaas@...gle.com>,
        <matthias.bgg@...il.com>, <lorenzo.pieralisi@....com>,
        <ryder.lee@...iatek.com>, <jianjun.wang@...iatek.com>,
        <yong.wu@...iatek.com>, <linux-pci@...r.kernel.org>,
        <linux-mediatek@...ts.infradead.org>, <devicetree@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v12 3/6] PCI: mediatek: Add new method to get irq number

On Tue, 2021-08-31 at 13:30 -0500, Bjorn Helgaas wrote:
> On Mon, Aug 23, 2021 at 11:27:57AM +0800, Chuanjia Liu wrote:
> > Use platform_get_irq_byname() to get the irq number
> > if the property of "interrupt-names" is defined.
> 
> From patch 1/6, I have the impression that this patch is part of
> fixing an MSI issue.  If so, this commit log should mention that as
> well.

Hi ,Bjorn
Yes，I will change the commit message as follow
 
In order to parse the new dts format that conforms to the hardware
design and fixes the MSI issue，add
platform_get_irq_byname_optional to get the irq number.
 
> 
> > Signed-off-by: Chuanjia Liu <chuanjia.liu@...iatek.com>
> > Acked-by: Ryder Lee <ryder.lee@...iatek.com>
> > ---
> >  drivers/pci/controller/pcie-mediatek.c | 6 +++++-
> >  1 file changed, 5 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/pci/controller/pcie-mediatek.c
> > b/drivers/pci/controller/pcie-mediatek.c
> > index 4296d9e04240..19e35ac62d43 100644
> > --- a/drivers/pci/controller/pcie-mediatek.c
> > +++ b/drivers/pci/controller/pcie-mediatek.c
> > @@ -654,7 +654,11 @@ static int mtk_pcie_setup_irq(struct
> > mtk_pcie_port *port,
> >  		return err;
> >  	}
> >  
> > -	port->irq = platform_get_irq(pdev, port->slot);
> > +	if (of_find_property(dev->of_node, "interrupt-names", NULL))
> > +		port->irq = platform_get_irq_byname(pdev, "pcie_irq");
> > +	else
> > +		port->irq = platform_get_irq(pdev, port->slot);
> 
> This would be the only instance of this pattern, where we look for a
> property and use the result to decide how to look for the IRQ.
> 
> dw_pcie_host_init() does something like this:
> 
>   port->irq = platform_get_irq_byname_optional(pdev, "pcie_irq");
>   if (port->irq < 0) {
>     port->irq = platform_get_irq(pdev, port->slot);
>     if (port->irq < 0)
>       return port->irq;
>   }
> 
> Would that work for you?  If not, the commit log should explain why
> you can't use the standard pattern.
> 
> If you do things differently than other drivers, it makes things
> harder to review and slows things down.  If you *have* to do
> something
> differently and it adds real value to be different, that's fine.  But
> we should avoid unnecessary differences.

Thanks for your advice，it is very helpful to me, I will use standard
pattern to avoid unnecessary differences

Thanks again!
Chuanjia

> 
> >  	if (port->irq < 0)
> >  		return port->irq;
> >  
> > -- 
> > 2.18.0
> >