bcma: gpio: Convert to immutable gpio irqchip

This switches the BCMA gpio irqchip to be immutable. The GPIO subsystem plays
tricks on the irqchip structures, and we're fixing it one driver at a time. See
merge commit 4bde53a ("Merge branch irq/gpio-immutable into
irq/irqchip-next") for all the details.

Tested on the D-Link DWL-6810AP.

Cc: Marc Zyngier <maz@kernel.org>
Cc: Bartosz Golaszewski <brgl@bgdev.pl>
Cc: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Bartosz Golaszewski <brgl@bgdev.pl>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20221012192348.2234478-1-linus.walleij@linaro.org

drivers/bcma/driver_gpio.c

@@ -82,6 +82,7 @@ static void bcma_gpio_irq_unmask(struct irq_data *d)
 	int gpio = irqd_to_hwirq(d);
 	u32 val = bcma_chipco_gpio_in(cc, BIT(gpio));
 
+	gpiochip_enable_irq(gc, gpio);
 	bcma_chipco_gpio_polarity(cc, BIT(gpio), val);
 	bcma_chipco_gpio_intmask(cc, BIT(gpio), BIT(gpio));
 }
@@ -93,12 +94,15 @@ static void bcma_gpio_irq_mask(struct irq_data *d)
 	int gpio = irqd_to_hwirq(d);
 
 	bcma_chipco_gpio_intmask(cc, BIT(gpio), 0);
+	gpiochip_disable_irq(gc, gpio);
 }
 
-static struct irq_chip bcma_gpio_irq_chip = {
+static const struct irq_chip bcma_gpio_irq_chip = {
 	.name		= "BCMA-GPIO",
 	.irq_mask	= bcma_gpio_irq_mask,
 	.irq_unmask	= bcma_gpio_irq_unmask,
+	.flags		= IRQCHIP_IMMUTABLE,
+	GPIOCHIP_IRQ_RESOURCE_HELPERS,
 };
 
 static irqreturn_t bcma_gpio_irq_handler(int irq, void *dev_id)
@@ -139,7 +143,7 @@ static int bcma_gpio_irq_init(struct bcma_drv_cc *cc)
 	bcma_chipco_gpio_intmask(cc, ~0, 0);
 	bcma_cc_set32(cc, BCMA_CC_IRQMASK, BCMA_CC_IRQ_GPIO);
 
-	girq->chip = &bcma_gpio_irq_chip;
+	gpio_irq_chip_set_chip(girq, &bcma_gpio_irq_chip);
 	/* This will let us handle the parent IRQ in the driver */
 	girq->parent_handler = NULL;
 	girq->num_parents = 0;