hi Shenwei
On 11/6/25 17:26, Shenwei Wang wrote:
Hi Arnaud,
-----Original Message-----
From: Arnaud POULIQUEN <[email protected]>
Sent: Thursday, November 6, 2025 4:17 AM
To: Shenwei Wang <[email protected]>; Peng Fan <[email protected]>;
Bjorn Andersson <[email protected]>; Mathieu Poirier
<[email protected]>; Rob Herring <[email protected]>; Krzysztof
Kozlowski <[email protected]>; Conor Dooley <[email protected]>; Shawn
Guo <[email protected]>; Sascha Hauer <[email protected]>;
Jonathan Corbet <[email protected]>; Linus Walleij <[email protected]>;
Bartosz Golaszewski <[email protected]>
Cc: Pengutronix Kernel Team <[email protected]>; Fabio Estevam
<[email protected]>; [email protected];
[email protected]; [email protected]; linux-arm-
[email protected]; [email protected]; linux-
[email protected]; dl-linux-imx <[email protected]>; Randy Dunlap
<[email protected]>; Andrew Lunn <[email protected]>; linux-
[email protected]
Subject: [EXT] Re: [PATCH v5 0/5] Enable Remote GPIO over RPMSG on i.MX
Platform
Hi Shenwei,
On 11/5/25 15:12, Shenwei Wang wrote:
Hi Arnaud,
-----Original Message-----
On 11/5/25 02:12, Peng Fan wrote:
Hi Shenwei
Subject: [PATCH v5 0/5] Enable Remote GPIO over RPMSG on i.MX
Platform
Support the remote devices on the remote processor via the RPMSG
bus on i.MX platform.
I have not look into the details of new version, but before that,
just want to check, have we agreed on what Arnaud suggested?
or continue to proceed to be this as i.MX specific?
Thanks, Peng, for pointing this out. Regarding the V3 discussions, it
seems that I am not the only one suggesting a generic driver.
As I mentioned before, the only i.MX-specific part is the transport protocol
over
the RPMSG bus.
In this v5 patches, we’ve included detailed documentation for the
protocol in a separate file. Any platform that follows the same protocol should
work right out of the box.
If you spot anything that could be improved, please let me know!
My concerns remain the same as those shared previously:
1) The simpler one: gpio-imx-rpmsg.c should be renamed to gpio-rpmsg.c.
Agree. Will fix it in the next version.
2) The more complex one: the driver should be independent of the remoteproc
driver. The rpmsg protocol relies on virtio and can be used in contexts other
than
remoteproc. In other words, the struct rpmsg_driver and its associated
operations should be defined within the rpmsg-gpio driver, not in the remoteproc
driver.
The GPIO driver operates independently of the remoteproc driver.
The channel_device_map table in imx_rproc.c would give me the opposite
feeling
It functions based
on the defined GPIO-RPMSG transport protocol. Any remoteproc that supports
this protocol can exchange data with the GPIO driver via the underlying rpmsg
bus.
Placing the rpmsg_driver (which manages the rpmsg channel) within the remoteproc
driver is more logical, as rpmsg channels run on the rpmsg bus. This bus is
defined inside
the remoteproc device tree node and is populated by the corresponding
remoteproc driver.
Regarding imx_of_rpmsg_node_init(), It seems you rely on device tree in
the rproc platform to register rpmsg drivers. This implies you are
creating drivers based on a device description. To me, this does not
appear to be a valid implementation, but perhaps such an approach
already exists in the Linux kernel?
For your information, I'm facing a similar issue with my remoteproc_tee
series [1]. The advice I received was to look at the PCIe DT
implementation (I haven't had time to explore it yet). This advice also
seems relevant to your series.
Do you also have a look to rpmsg_virtio_bus ? it seems a good candidate
to match the device tree properties with the rpmsg device?
In the end, this is my point of view. Perhaps it is better to wait for
others before deciding on the direction...
Thanks,
Arnaud
[1]https://lists.infradead.org/pipermail/linux-arm-kernel/2025-October/1069154.html
Thanks,
Shenwei
Thanks,
Arnaud
Thanks,
Shenwei
Thanks,
Arnaud
Thanks
Peng.
