Re: [PATCH] pinctrl: aspeed: Allow changing hardware strap defaults

[Zev Weiss]

On Wed, Oct 04, 2023 at 06:17:50PM PDT, Andrew Jeffery wrote:
> On Wed, 2023-10-04 at 00:16 -0700, Zev Weiss wrote:
> > Previously we've generally assumed that the defaults in the hardware
> > strapping register are in fact appropriate for the system and thus
> > have avoided making any changes to its contents (with the exception of
> > the bits controlling the GPIO passthrough feature).
> >
> > Unfortunately, on some platforms corrections from software are
> > required as the hardware strapping is simply incorrect for the system
> > (such as the SPI1 interface being configured for passthrough mode when
> > master mode is in fact the only useful configuration for it).  We thus
> > remove the checks preventing changes to the strap register so that the
> > pinctrl subsystem can be used for such corrections.
>
> So the strapping for the SPI1 configuration seems to be prone to
> (copy/paste?) mistakes. Is there evidence that motivates dropping all
> the protection instead of poking a hole for SPI1 like we did for the
> passthrough GPIOs?
>
> I'm still a little attached to the policy that software should be
> beholden to the strapping, and to try to mitigate software mistakes
> given the smattering of bits required to drive the Aspeed pinmux.

I have no idea what else might be lurking out there so I took a broader 
(perhaps overly heavy-handed) approach, but the SPI1 mode bits are the 
only ones I've personally encountered being strapped wrong, so sure, I'd 
be fine with just extending the "hole-punch" a bit to add those bits.  
I'll send a v2 doing that shortly.


Thanks,
Zev