Re: [PATCH v1 5/5] gpio: pca953x: Override GpioInt() pin for Intel Galileo Gen 2

[Mika Westerberg <mika.westerberg@linux.intel.com>]

On Mon, May 25, 2020 at 02:35:51PM +0300, Andy Shevchenko wrote:
> On Mon, May 25, 2020 at 02:05:56PM +0300, Mika Westerberg wrote:
> > On Mon, May 25, 2020 at 01:13:35PM +0300, Andy Shevchenko wrote:
> > > Due to parsing of ACPI tables. I don't want to copy'n'paste 25% of
> > > gpiolib-acpi.c in here. I think provided solution is cleaner and (more)
> > > flexible in terms of maintenance.
> > 
> > Hmm, you seem to pass a hard-coded pin number (1) to the core that then
> > passes it back to the driver. Why you can't simple use that number here
> > directly? You don't need to parse anything. What I'm missing? :-)
> 
> Okay, so, AFAIU you are proposing something like this:
> 
> 1) find a GPIO controller by the ACPI path (somehow, I guess by finding a
>    handle followed by physical device behind it); 2) somehow to request a
>    pin from that device by number;
> 3) convert to IRQ and use.
> 
> Is it correct?

Well, no. In the first patch you do this:

  pin = lookup->info.quirks_data;

and this essentially becomes 1 so you know the pin number upfront in the
driver. Why not simply get GPIO number 1 in the driver and use it as an
interrupt? You know already that this particular board with the matching
DMI identifier always uses the this number anyway.