Re: [RFC PATCH 8/9] pinctrl: sunxi: a523-r: add a733-r compatible string

[Andre Przywara <andre.przywara@arm.com>]

Hi Julian,

I know this email is almost comically old, but still didn't want this 
left unanswered before sending a new revision:

On 8/24/25 01:09, Julian Calaby wrote:
> Hi Andre,
> 
> On Thu, Aug 21, 2025 at 10:46 AM Andre Przywara <andre.przywara@arm.com> wrote:
>>
>> The secondary Allwinner A733 pincontroller ("-r") is interestingly not
>> using the same new MMIO frame layout as the main controller, but is in
>> fact very similar to the A523-r one: it has two banks, with 14 and 6 pins
>> each. From the driver's perspective, this is all we care about, so we can
>> re-use the a523-r pinctrl driver for the a733-r, too.
>>
>> The individual pinmux settings are different, so we must not use the
>> a523-r compatible string as a fallback, but we can surely let the same
>> driver care for both the a523-r and a733-r IP, as the pinmux values will
>> be provided by the DT.
> 
> If the bank and pin counts are the same and the pinmux values are
> provided by the DT, that means they _are_ compatible, right?

I wouldn't say so: I would argue the devices are different, and not 
necessarily every driver written for the old device can cope with the 
new one. For instance U-Boot still goes with hardcoded pinmux tables 
(because that's simpler to implement there), which don't match between 
A523-R and A733-R.
And I would see a point if that would enable old kernels to use that new 
SoC, but because the main pinctrl is different anyway, that doesn't help us.

But it's not a very strong opinion, so if the maintainers disagree with 
me, I am happy to change that.

Cheers,
Andre