mt7621 GPIO mapping mystery

Peter Naulls peter at
Mon Jan 23 09:17:09 PST 2023

On 1/22/23 13:58, Daniel Santos wrote:


Thanks Daniel and all the others (to many to mention).  Yes, I should have read 
the datasheet much earlier, so in the end I really have only myself to blame.

The fix was simply to add back in the "rgmii2" group back into the gpio group. 
I believe I previously removed this in order to try and figure out the handling 
of the ethernet switch in the newer kernel - another poorly documented and very 
confusing change that got made that took me a while to figure out (clue,
swconfig is deprecated and no longer works on mt7621).

As a very long time embedded developer, but only occasional kernel hacker,
this stuff is hard to keep track of. I understand that OpenWrt is highly
volunteer driven with limited resources, and to some extent we're subject
to the vagaries of mainstream kernel hacking, but this clearly could have
been better documented - again, I don't think that's anyone's fault, but
it's still frustrating.

I agree with the sentiment that OpenWrt could be more hacker friendly. I
don't particularly need to dynamic pin grouping, but it might have
been nice to know about in kernel reporting or libgpiod output, etc.

I would kindly suggest that major subsystem changes in the future be updated
in the wiki.  Even if it's just a link to relevant kernel development.

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