Re: [PATCH 1/7] dt-bindings: pinctrl: Add support for Broadcom STB pin controller

Hi Dave,

Am 12.08.24 um 18:28 schrieb Dave Stevenson:

Hi Stefan

Sorry for the delay in responding - I was on holiday last week.

no problem and thanks for the explanations.

quoted

I'm missing an explanation in the commit message, what's the difference
between brcm,bcm2712-pinctrl and brcm,bcm2712-aon-pinctrl?

Two separate instantiations of the same IP block, but they differ in
the number of pins that are associated and the pinmux functions for
each of those pins. AFAIK there is no way from DT to specify those
pinmux function names, so otherwise
/sys/kernel/debug/pinctrl/<node>/pins will give the wrong function
mappings.

Yes, my request is that this or a similar explanation should go to the
commit message, because not all reviewers know the IP block. It would be
great to explain the aon part. Always on?

quoted

According to the driver brcm,bcm2712-pinctrl is the same as
brcm,bcm2712c0-pinctrl. So the former is more a fallback?

I'd need to check with Phil (who's on holiday this week) or Dom, but I
believe you are correct that "brcm,bcm2712-pinctrl" is a fallback.
Most likely due to our early DT files not having the c0 designation.
Obviously for mainline that is irrelevant, so dropping the
non-specific compatibles is fine.

I agree.

Regards

I hope that makes some more sense.

   Dave

[1] https://github.com/raspberrypi/linux/blob/rpi-6.6.y/arch/arm64/boot/dts/broadcom/bcm2712d0-rpi-5-b.dts
[2] https://github.com/raspberrypi/linux/blob/rpi-6.6.y/arch/arm64/boot/dts/broadcom/bcm2712-rpi-5-b.dts