Re: [PATCH v3 3/4] gpio: imx-rpmsg: add imx-rpmsg GPIO driver

[Shenwei Wang]

> -----Original Message-----
> From: Andrew Lunn <andrew@xxxxxxx>
> Sent: Monday, October 13, 2025 11:56 AM
> To: Shenwei Wang <shenwei.wang@xxxxxxx>
> Cc: Bjorn Andersson <andersson@xxxxxxxxxx>; Mathieu Poirier
> <mathieu.poirier@xxxxxxxxxx>; Rob Herring <robh@xxxxxxxxxx>; Krzysztof
> Kozlowski <krzk+dt@xxxxxxxxxx>; Conor Dooley <conor+dt@xxxxxxxxxx>; Shawn
> Guo <shawnguo@xxxxxxxxxx>; Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>; Linus
> Walleij <linus.walleij@xxxxxxxxxx>; Bartosz Golaszewski <brgl@xxxxxxxx>;
> Pengutronix Kernel Team <kernel@xxxxxxxxxxxxxx>; Fabio Estevam
> <festevam@xxxxxxxxx>; Peng Fan <peng.fan@xxxxxxx>; linux-
> remoteproc@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; imx@xxxxxxxxxxxxxxx;
> linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; dl-linux-imx
> <linux-imx@xxxxxxx>
> Subject: [EXT] Re: [PATCH v3 3/4] gpio: imx-rpmsg: add imx-rpmsg GPIO driver
> > > Notice how ENOPNOTSUPP can be 45, 122, 223, or 95. Returning
> > > EL2NSYNC or EDQUOT to user space is going to cause confusion...
> > >
> >
> 
> > I think we should just follow the definitions in
> > include/uapi/asm-generic/errno.h, right?
> 
> No.
> 
> Try a make for mips, and look at includes you end up with. You will find it goes
> something like:
> 
> # 1 "./arch/mips/include/asm/errno.h" 1
> # 11 "./arch/mips/include/asm/errno.h"
> # 1 "./arch/mips/include/uapi/asm/errno.h" 1 # 16
> "./arch/mips/include/uapi/asm/errno.h"
> # 1 "./include/uapi/asm-generic/errno-base.h" 1 # 17
> "./arch/mips/include/uapi/asm/errno.h" 2
> 
> and this results in
> 
> #define EOPNOTSUPP      122     /* Operation not supported on transport
> endpoint */
> 
> not what you get from asm-generic/errno.h:
> 
> #define EOPNOTSUPP      95      /* Operation not supported on transport endpoint
> */
> 

That shouldn't be an issue in this case. 
For instance, if we define the error code as 1 in the return message, the driver will interpret it and just return -EOPNOTSUPP, regardless of the architecture.

Thanks,
Shenwei

>         Andrew