[PATCH] drivers/tty/serial/8250: Make Aspeed VUART SIRQ polarity configurable

[Oskar Senft]

Hi Jeremy

In my understanding the SIRQ polarity should be the same for all UARTs on
the particular bus, i.e. both UARTs controlled by the SuperI/O and the
VUART or PUART (pass-through). However, the host controls the UARTs on the
SuperI/O itself. The VUART is covered by this code and we don't have a
PUART driver yet.

It might make sense to have this as a global setting which each driver
could read. But wouldn't this be an exercise for the future where we
actually have a second device? I don't think the Aspeed currently has any
other devices that could generate a SIRQ (except for the PUART for which
there's no driver).

Having said that, ideally I'd like the SIRQ polarity to be auto-configured
from the LPC/eSPI HW pin strap anyway. I have the code for that almost
done. Maybe we shouldn't even have the sysfs interface for it and I should
strip that out?

Thanks
Oskar.

On Sun, Jul 28, 2019 at 8:51 PM Jeremy Kerr <jk at ozlabs.org> wrote:

> Hi Oskar,
>
> > For LPC, the polarity should be set to 1, for eSPI the default of 0 is
> > correct.
>
> Would there ever be a case where different SIRQs need different
> polarities? If not, we may want this to be global, rather than for each
> device (the VUART being one...)
>
> Cheers,
>
>
> Jeremy
>
>
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