Hello Conor,

On Tue Mar 10, 2026 at 6:17 PM CET, Conor Dooley wrote:

At the very least, it'd be good of the soc vendor folks could check
their platforms and see if their usrio stuff actually lines up with what
the driver currently calls "macb_default_usrio". Ours didn't and it was
a nasty surprise.

Theo, you added eyeq5 recently. Does it genuinely have the same usrio
bits as the at91 devices?

Sorry I missed your direct mention. After checking (because I completely
ignored this part of the code before), the User I/O feature is disabled
on EyeQ5 & EyeQ6H. It can be seen from DCFG1 BIT(9). It was invisible
because the USRIO register turns read-only when User I/O is disabled.

1. So I thought about adding runtime detection.

2. But then having eyeq5_config->usrio made no sense so I dropped it.

3. And then I thought that a config having usrio being NULL should
   imply MACB_CAPS_USRIO_DISABLED to ensure we don't NULL dereference
   the bp->usrio pointer.

#1 is useless for EyeQ combined with #2 and #3, but it should be useful
for the many compatibles that inherited the wrong default value of
at91_default_usrio.

I am sending those three patches as a reply, feel free to pick them up
if you consider them useful. They apply on top of your series and have
been tested on EyeQ5.

Thanks Conor,

--
Théo Lebrun, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com