Re: [PATCH net-next 1/3] dt-bindings: net: fsl, fec: add "fsl, wakeup-irq" property

[Florian Fainelli]

On 8/8/2021 10:08 PM, Joakim Zhang wrote:
> Hi Florian,
>
> > -----Original Message-----
> > From: Florian Fainelli <f.fainelli@xxxxxxxxx>
> > Sent: 2021年8月5日 17:18
> > To: Joakim Zhang <qiangqing.zhang@xxxxxxx>; davem@xxxxxxxxxxxxx;
> > kuba@xxxxxxxxxx; robh+dt@xxxxxxxxxx; shawnguo@xxxxxxxxxx;
> > s.hauer@xxxxxxxxxxxxxx; festevam@xxxxxxxxx; andrew@xxxxxxx
> > Cc: kernel@xxxxxxxxxxxxxx; dl-linux-imx <linux-imx@xxxxxxx>;
> > netdev@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx;
> > linux-kernel@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
> > Subject: Re: [PATCH net-next 1/3] dt-bindings: net: fsl, fec: add "fsl,
> > wakeup-irq" property
> >
> >
> >
> > On 8/5/2021 12:46 AM, Joakim Zhang wrote:
> > > Add "fsl,wakeup-irq" property for FEC controller to select wakeup irq
> > > source.
> > >
> > > Signed-off-by: Fugang Duan <fugang.duan@xxxxxxx>
> > > Signed-off-by: Joakim Zhang <qiangqing.zhang@xxxxxxx>
> >
> > Why are not you making use of the standard interrupts-extended property
> > which allows different interrupt lines to be originating from different interrupt
> > controllers, e.g.:
> >
> > interrupts-extended = <&gic GIC_SPI 112 4>, <&wakeup_intc 0>;
>
> Thanks.
>
> AFAIK, interrupts-extended should be used instead of interrupts when a device is connected to multiple interrupt controllers
> as it encodes a parent phandle with each interrupt specifier. However, for FEC controller, all interrupt lines are originating from
> the same interrupt controllers.

OK, so why this custom property then?

> 1) FEC controller has up to 4 interrupt lines and all of these are routed to GIC interrupt controller.
> 2) FEC has a wakeup interrupt signal and always are mixed with other interrupt signals, and then output to one interrupt line.
> 3) For legacy SoCs, wakeup interrupt are mixed to int0 line, but for i.MX8M serials, are mixed to int2 line.
> 4) Now driver treat int0 as the wakeup source by default, it is broken for i.MX8M.

I don't really know what to make of your response, it seems to me that 
you are carrying some legacy Device Tree properties that were invented 
when interrupts-extended did not exist and we did not know any better.
--
Florian