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

[Shenwei Wang]

> -----Original Message-----
> From: Andrew Lunn <andrew at lunn.ch>
> Sent: Thursday, February 19, 2026 7:27 AM
> To: Arnaud POULIQUEN <arnaud.pouliquen at foss.st.com>
> Cc: Shenwei Wang <shenwei.wang at nxp.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
> 
> > > +   if (sync) {
> > > +           err = wait_for_completion_timeout(&info->cmd_complete,
> > > +                                             msecs_to_jiffies(RPMSG_TIMEOUT));
> > > +           if (err == 0) {
> > > +                   dev_err(&info->rpdev->dev, "rpmsg_send timeout!\n");
> > > +                   return -ETIMEDOUT;
> >
> > strange condition you return an error if err == 0, for redability use 'ret'
> > variable or simply:
> >
> >               if(!wait_for_completion_timeout(&info->cmd_complete,
> >                                 msecs_to_jiffies(RPMSG_TIMEOUT)) {
> >                       dev_err(&info->rpdev->dev, "rpmsg_send timeout!\n");
> >                       return -ETIMEDOUT;
> >               }
> 
> This will be from a comment i made. It appears that
> do_wait_for_common() can return -ERESTARTSYS. I assume that should be
> returned to user space?
> 

It looks like there might be a bit of confusion around what wait_for_completion_timeout() 
actually returns. That function never returns -ERESTARTSYS. Instead, its behavior is pretty 
simple:

- 0 means the wait timed out
- A positive value means the completion happened (the value is just the remaining jiffies)

So the driver returns the timeout error, and the upper application can decide how it wants
to handle that situation, for example restart or ignore.

Thanks,
Shenwei

>         Andrew