[EXT] Re: [PATCH v8 3/4] gpio: rpmsg: add generic rpmsg GPIO driver

[Shenwei Wang]

> -----Original Message-----
> From: Andrew Lunn <andrew at lunn.ch>
> Sent: Tuesday, February 24, 2026 3:01 PM
> To: Shenwei Wang <shenwei.wang at nxp.com>
> Cc: Arnaud POULIQUEN <arnaud.pouliquen at foss.st.com>; Linus Walleij
> <linusw at kernel.org>; Bartosz Golaszewski <brgl at kernel.org>; Jonathan Corbet
> <corbet at lwn.net>; Rob Herring <robh at kernel.org>; Krzysztof Kozlowski
> <krzk+dt at kernel.org>; Conor Dooley <conor+dt at kernel.org>; Bjorn Andersson
> <andersson at kernel.org>; Mathieu Poirier <mathieu.poirier at linaro.org>; Frank Li
> <frank.li at nxp.com>; Sascha Hauer <s.hauer at pengutronix.de>; Shuah Khan
> <skhan at linuxfoundation.org>; linux-gpio at vger.kernel.org; linux-
> doc at vger.kernel.org; linux-kernel at vger.kernel.org; Pengutronix Kernel Team
> <kernel at pengutronix.de>; Fabio Estevam <festevam at gmail.com>; Peng Fan
> <peng.fan at nxp.com>; devicetree at vger.kernel.org; linux-
> remoteproc at vger.kernel.org; imx at lists.linux.dev; linux-arm-
> kernel at lists.infradead.org; dl-linux-imx <linux-imx at nxp.com>; Bartosz
> Golaszewski <brgl at bgdev.pl>
> Subject: [EXT] Re: [PATCH v8 3/4] gpio: rpmsg: add generic rpmsg GPIO driver
> > > How does port_idx fit into this?
> >
> > I think you were assuming there is only one remoteproc in the system?
> > In practice, the setup can look more like this:
> >
> > + remote_cm33{
> > +     rpmsg {
> > +        rpmsg-io-channel {
> > +          #address-cells = <1>;
> > +          #size-cells = <0>;
> > +
> > +          gpio at 0 {
> > +            compatible = "rpmsg-gpio";
> > +            reg = <0>;
> > +            gpio-controller;
> > +            #gpio-cells = <2>;
> > +            #interrupt-cells = <2>;
> > +            interrupt-controller;
> > +          };
> > +          gpio at 1 {
> > +            compatible = "rpmsg-gpio";
> > +            reg = <1>;
> > +            gpio-controller;
> > +            #gpio-cells = <2>;
> > +            #interrupt-cells = <2>;
> > +            interrupt-controller;
> > +          };
> > +  ...
> > +        };
> > +      };
> > +};
> > +
> > + remote_dsp {
> > +     rpmsg {
> > +        rpmsg-io-channel {
> > +          #address-cells = <1>;
> > +          #size-cells = <0>;
> > +
> > +          gpio at 0 {
> > +            compatible = "rpmsg-gpio";
> > +            reg = <0>;
> > +            gpio-controller;
> > +            #gpio-cells = <2>;
> > +            #interrupt-cells = <2>;
> > +            interrupt-controller;
> > +          };
> > +  ...
> > +        };
> > +      };
> > +};
> 
> And why would this require a port_idx? If they are different rpmsg instances, the
> channel numbers are in different address spaces.
> 

Then how would you distinguish gpio at 0 from gpio at 1 on the CM33 RPMSG bus in the example above?
They are running on the same transport.

Thanks,
Shenwei

>         Andrew