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

Hi Geert,

Thank you for the review.

On Thu, May 12, 2022 at 8:29 AM Geert Uytterhoeven [off-list ref] wrote:

Hi Prabhakar,

On Wed, May 11, 2022 at 8:32 PM Lad Prabhakar
[off-list ref] wrote:

quoted

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>

Thanks for your patch!

quoted

--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c

@@ -1221,7 +1221,7 @@ static int gpiochip_hierarchy_add_domain(struct gpio_chip *gc)
        gc->irq.domain = irq_domain_create_hierarchy(
                gc->irq.parent_domain,
                0,
-               gc->ngpio,
+               gc->irq.ngirq ?: gc->ngpio,
                gc->irq.fwnode,
                &gc->irq.child_irq_domain_ops,
                gc);

@@ -1574,7 +1574,7 @@ static int gpiochip_add_irqchip(struct gpio_chip *gc,
        } else {
                /* Some drivers provide custom irqdomain ops */
                gc->irq.domain = irq_domain_create_simple(fwnode,
-                       gc->ngpio,
+                       gc->irq.ngirq ?: gc->ngpio,
                        gc->irq.first,
                        gc->irq.domain_ops ?: &gpiochip_domain_ops,
                        gc);

OK.

gpiochip_irqchip_remove() does:

        /* Remove all IRQ mappings and delete the domain */
        if (gc->irq.domain) {
                unsigned int irq;

                for (offset = 0; offset < gc->ngpio; offset++) {
                       if (!gpiochip_irqchip_irq_valid(gc, offset))

Hence it relies on gc->irq.valid_mask, which I think is OK in general.

Agreed.

                                continue;

                        irq = irq_find_mapping(gc->irq.domain, offset);
                        irq_dispose_mapping(irq);
                }

                irq_domain_remove(gc->irq.domain);

        }

quoted

--- a/include/linux/gpio/driver.h
+++ b/include/linux/gpio/driver.h

@@ -51,6 +51,14 @@ struct gpio_irq_chip {
         */
        const struct irq_domain_ops *domain_ops;

+       /**
+        * @ngirq:
+        *
+        * The number of GPIO IRQ's handled by this IRQ domain; usually is
+        * equal to ngpio.

"If not set, ngpio will be used."

sure will update the comment.

Cheers,
Prabhakar

quoted

+        */
+       u16 ngirq;
+
 #ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
        /**
         * @fwnode:

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds