Re: [RFC 0/3] Add Generic SPI GPIO model

[Peter Delevoryas]

On Mon, Aug 01, 2022 at 11:49:09AM +0930, Andrew Jeffery wrote:
> 
> 
> On Sun, 31 Jul 2022, at 06:48, Cédric Le Goater wrote:
> > On 7/29/22 19:30, Peter Delevoryas wrote:
> >> Certainly we'd like to use IRQ's instead, but she ran into correctness
> >> problems. Maybe we can investigate that further and fix it.
> 
> Yes, let's not work around problems that we have the ability to fix.

+1

> 
> >
> > So much is happening in that mode.
> 
> Yes, though while there's no-doubt accidental complexity in terms of 
> its implementation, the underlying hardware is also quite haphazard and 
> we need an approach that scales to the large number of GPIOs it 
> provides. So I'd argue there's a bunch of essential complexity involved 
> as well.

+1

> 
> Do we start with a fresh implementation that allows us to get the 
> expected behaviour and then build that out to replace the current 
> implementation?
> 
> Or, can we add more tests for the existing model to pin down where the 
> bugs are?

Mmmm good question, I think we might end up doing both. Tests would make
it much easier to develop either way though.

> 
> > We need more trace events in the Aspeed
> > GPIO model at least an extra in aspeed_gpio_update()
> 
> We can always fall back to this but my hope is we can get better test 
> coverage to iron out the bugs. Maybe that gets us a more refined and 
> maintainable model implementation along the way.

+1

> 
> Cheers,
> 
> Andrew
>