Re: [PATCH v3 4/5] gpio: gpiolib: Add ngirq member to struct gpio_irq_chip

Lad, Prabhakar
2022-05-18T18:36:59Z

Hi Linus,

Thank you for the review.

On Fri, May 13, 2022 at 9:47 PM Linus Walleij <linus.walleij@linaro.org> wrote:
>
> On Wed, May 11, 2022 at 8:32 PM Lad Prabhakar
> <prabhakar.mahadev-lad.rj@bp.renesas.com> wrote:
>
> > Supported GPIO IRQs by the chip is not always equal to the number of GPIO
> > pins. For example on Renesas RZ/G2L SoC where it has GPIO0-122 pins but at
> > a give point a maximum of only 32 GPIO pins can be used as IRQ lines in
> > the IRQC domain.
> >
> > This patch adds ngirq member to struct gpio_irq_chip and passes this as a
> > size to irq_domain_create_hierarchy()/irq_domain_create_simple() if it is
> > being set in the driver otherwise fallbacks to using ngpio.
> >
> > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
>
> As Geert says, I think you can just use .valid_mask for this,
> what do you say?
>
I don't think Geert is suggesting that. The .valid_mask option is one
time setting but what I need is something dynamic i.e. out of 392 GPIO
pins any 32 can be used as an interrupt pin. Also with this patch we
also save on memory [0].

[0] https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/kernel/irq/irqdomain.c?h=next-20220518#n153

Cheers,
Prabhakar