Re: [PATCH v2] gpio: mt7621: fix interrupt banks mapping on gpio chips

[Sergio Paracuellos]

Hi,

On Mon, Jun 8, 2026 at 11:05 AM Bartosz Golaszewski <brgl@xxxxxxxxxx> wrote:
>
> On Tue, 2 Jun 2026 16:25:13 +0200, Sergio Paracuellos
> <sergio.paracuellos@xxxxxxxxx> said:
> > The GPIO controller's registers are organized as sets of eight 32-bit
> > registers with each set controlling a bank of up to 32 pins. A single
> > interrupt is shared for all of the banks handled by the controller.
> > The driver implements this using three gpio chip instances every one
> > with its own irq chip. Every single pin can generate interrupts having
> > a total of 96 possible interrupts here. It looks like there is a problem
> > with interrupts being properly mapped to the gpio bank using this solution.
> > This problem report is in the following lore's link [0].
> >
> > Device tree is using two cells for this, so only the interrupt pin and the
> > interrupt type are described there. Changing to have three cells to setup
> > also the bank and implement 'of_node_instance_match()' would also work but
> > this would be an ABI breakage and also a bit incoherent since gpios itself
> > are also using two cells and properly mapped in desired bank using through
> > its pin number on 'of_xlate()'.
> >
> > That said, register a linear IRQ domain of the total of 96 interrupts shared
> > with the three gpio chip instances so the bank and the interrupt is properly
> > decoded and devices using gpio IRQs properly work.
> >
> > [0]: https://lore.kernel.org/linux-gpio/CAAMcf8C_A9dJ_v4QRKtb9eGNOpJ7BZNOGsFP4i2WFOZxOVBPnQ@xxxxxxxxxxxxxx/T/#u
> >
> > Fixes: 4ba9c3afda41 ("gpio: mt7621: Add a driver for MT7621")
> > Co-developed-by: Vicente Bergas <vicencb@xxxxxxxxx>
> > Signed-off-by: Vicente Bergas <vicencb@xxxxxxxxx>
> > Tested-by: Vicente Bergas <vicencb@xxxxxxxxx>
> > Signed-off-by: Sergio Paracuellos <sergio.paracuellos@xxxxxxxxx>
> > ---
>
> Hi!
>
> Can you look at the sashiko review? Especially the bit about tracking the
> GPIOD_FLAG_IRQ_IS_ENABLED flag looks correct.

I got rid of those two calls (gpiochip_enable_irq() and
gpiochip_disable_irq()) because the driver "gpio-brcmstb" which is the
one I based my changes on was not used them at all. We have not found
anything weird related with that on testing. I do believe that since
we are using our own callbacks for 'irq_request_resources()' and
'irq_release_resources()' we are safe here. Regarding the others I am
not sure, but the introduction of the remove stuff for the irq domain
is because there are no devm_* functions for that. Other resources in
driver are using devm versions so I think the changes are ok as they
are...

Best regards,
     Sergio Paracuellos
>
> Bart