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

[Joakim Zhang <qiangqing.zhang@nxp.com>]

Hi Florian,

> -----Original Message-----
> From: Florian Fainelli <f.fainelli@gmail.com>
> Sent: 2021年8月5日 17:18
> To: Joakim Zhang <qiangqing.zhang@nxp.com>; davem@davemloft.net;
> kuba@kernel.org; robh+dt@kernel.org; shawnguo@kernel.org;
> s.hauer@pengutronix.de; festevam@gmail.com; andrew@lunn.ch
> Cc: kernel@pengutronix.de; dl-linux-imx <linux-imx@nxp.com>;
> netdev@vger.kernel.org; devicetree@vger.kernel.org;
> linux-kernel@vger.kernel.org; linux-arm-kernel@lists.infradead.org
> 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@nxp.com>
> > Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com>
> 
> 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.

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.

Best Regards,
Joakim Zhang
> --
> Florian