Re: [PATCH v5 3/5] docs: staging: gpio-rpmsg: gpio over rpmsg bus

Shenwei Wang
2025-11-12T16:31:56Z

> -----Original Message-----
> From: Andrew Lunn <andrew@lunn.ch>
> Sent: Wednesday, November 12, 2025 7:42 AM
> To: Shenwei Wang <shenwei.wang@nxp.com>
> Cc: Linus Walleij <linus.walleij@linaro.org>; Bjorn Andersson
> <andersson@kernel.org>; Mathieu Poirier <mathieu.poirier@linaro.org>; Rob
> Herring <robh@kernel.org>; Krzysztof Kozlowski <krzk+dt@kernel.org>; Conor
> Dooley <conor+dt@kernel.org>; Shawn Guo <shawnguo@kernel.org>; Sascha
> Hauer <s.hauer@pengutronix.de>; Jonathan Corbet <corbet@lwn.net>; Bartosz
> Golaszewski <brgl@bgdev.pl>; Pengutronix Kernel Team
> <kernel@pengutronix.de>; Fabio Estevam <festevam@gmail.com>; Peng Fan
> <peng.fan@nxp.com>; linux-remoteproc@vger.kernel.org;
> devicetree@vger.kernel.org; imx@lists.linux.dev; linux-arm-
> kernel@lists.infradead.org; linux-kernel@vger.kernel.org; linux-
> doc@vger.kernel.org; dl-linux-imx <linux-imx@nxp.com>
> Subject: [EXT] Re: [PATCH v5 3/5] docs: staging: gpio-rpmsg: gpio over rpmsg bus
>
> Since this has not been merged yet, there are no existing systems.
>

In this context, "system" refers to both Linux and the remote firmware. The remote firmware
for i.MX platforms has already been released and widely used by our customers. Maintaining
compatibility with the existing firmware would provide a better solution for customers.

Thanks,
Shenwei

> It is well known that what gets merged into mainline is often different to the
> initial out of tree version. You just need to deal with it. One option you have is to
> set the vendor byte to 1, so indicating NXP. If Linux uses vendor 0, it might be
> your out of tree vendor driver, not the in kernel driver. Just document in the
> specification vendor 0 is reserved.
>
> You are going to have to modify your firmware anyway, level interrupts are
> broken. And this is an example of why quirks are needed.
>
> Andrew