[PATCH] gpio: rcar: Make the irqchip immutable

[Geert Uytterhoeven <geert+renesas@xxxxxxxxx>]

Commit 6c846d026d49 ("gpio: Don't fiddle with irqchips marked as
immutable") added a warning to indicate if the gpiolib is altering the
internals of irqchips.  Following this change the following warning is
now observed for the gpio-rcar driver:

    gpio gpiochip0: (e6050000.gpio): not an immutable chip, please consider fixing it!

Fix this by making the irqchip in the gpio-rcar driver immutable.

Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
---
Against linux-next.
Tested on the koelsch development board (R-Car M2-W).

On Tue, Apr 5, 2022 at 4:07 PM Marc Zyngier <maz@xxxxxxxxxx> wrote:
> Nothing breaks, the volume of change is small, the memory usage goes
> down and we have fewer callbacks that can be used as attack vectors.
> What's not to love?

Does it?

    arm32$ size drivers/gpio/gpio-rcar.o{.orig,}
       text	   data	    bss	    dec	    hex	filename
       4543	    112	     24	   4679	   1247	drivers/gpio/gpio-rcar.o.orig
       4647	    112	     24	   4783	   12af	drivers/gpio/gpio-rcar.o

    arm64$ size drivers/gpio/gpio-rcar.o{.orig,}
       text	   data	    bss	    dec	    hex	filename
       4919	    216	     48	   5183	   143f	drivers/gpio/gpio-rcar.o.orig
       5159	    216	     48	   5423	   152f	drivers/gpio/gpio-rcar.o
---
 drivers/gpio/gpio-rcar.c | 25 ++++++++++++++-----------
 1 file changed, 14 insertions(+), 11 deletions(-)

diff --git a/drivers/gpio/gpio-rcar.c b/drivers/gpio/gpio-rcar.c
index 9a1e0c37c04baa58..6d1b105a4ae81f75 100644
--- a/drivers/gpio/gpio-rcar.c
+++ b/drivers/gpio/gpio-rcar.c
@@ -44,7 +44,6 @@ struct gpio_rcar_priv {
 	spinlock_t lock;
 	struct device *dev;
 	struct gpio_chip gpio_chip;
-	struct irq_chip irq_chip;
 	unsigned int irq_parent;
 	atomic_t wakeup_path;
 	struct gpio_rcar_info info;
@@ -98,6 +97,7 @@ static void gpio_rcar_irq_disable(struct irq_data *d)
 	struct gpio_rcar_priv *p = gpiochip_get_data(gc);
 
 	gpio_rcar_write(p, INTMSK, ~BIT(irqd_to_hwirq(d)));
+	gpiochip_disable_irq(gc, d->hwirq);
 }
 
 static void gpio_rcar_irq_enable(struct irq_data *d)
@@ -105,6 +105,7 @@ static void gpio_rcar_irq_enable(struct irq_data *d)
 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
 	struct gpio_rcar_priv *p = gpiochip_get_data(gc);
 
+	gpiochip_enable_irq(gc, d->hwirq);
 	gpio_rcar_write(p, MSKCLR, BIT(irqd_to_hwirq(d)));
 }
 
@@ -203,6 +204,17 @@ static int gpio_rcar_irq_set_wake(struct irq_data *d, unsigned int on)
 	return 0;
 }
 
+static const struct irq_chip gpio_rcar_irq_chip = {
+	.name		= "gpio-rcar",
+	.irq_mask	= gpio_rcar_irq_disable,
+	.irq_unmask	= gpio_rcar_irq_enable,
+	.irq_set_type	= gpio_rcar_irq_set_type,
+	.irq_set_wake	= gpio_rcar_irq_set_wake,
+	.flags		= IRQCHIP_IMMUTABLE | IRQCHIP_SET_TYPE_MASKED |
+			  IRQCHIP_MASK_ON_SUSPEND,
+	GPIOCHIP_IRQ_RESOURCE_HELPERS,
+};
+
 static irqreturn_t gpio_rcar_irq_handler(int irq, void *dev_id)
 {
 	struct gpio_rcar_priv *p = dev_id;
@@ -531,7 +543,6 @@ static int gpio_rcar_probe(struct platform_device *pdev)
 {
 	struct gpio_rcar_priv *p;
 	struct gpio_chip *gpio_chip;
-	struct irq_chip *irq_chip;
 	struct gpio_irq_chip *girq;
 	struct device *dev = &pdev->dev;
 	const char *name = dev_name(dev);
@@ -581,16 +592,8 @@ static int gpio_rcar_probe(struct platform_device *pdev)
 	gpio_chip->base = -1;
 	gpio_chip->ngpio = npins;
 
-	irq_chip = &p->irq_chip;
-	irq_chip->name = "gpio-rcar";
-	irq_chip->irq_mask = gpio_rcar_irq_disable;
-	irq_chip->irq_unmask = gpio_rcar_irq_enable;
-	irq_chip->irq_set_type = gpio_rcar_irq_set_type;
-	irq_chip->irq_set_wake = gpio_rcar_irq_set_wake;
-	irq_chip->flags = IRQCHIP_SET_TYPE_MASKED | IRQCHIP_MASK_ON_SUSPEND;
-
 	girq = &gpio_chip->irq;
-	girq->chip = irq_chip;
+	gpio_irq_chip_set_chip(girq, &gpio_rcar_irq_chip);
 	/* This will let us handle the parent IRQ in the driver */
 	girq->parent_handler = NULL;
 	girq->num_parents = 0;
-- 
2.25.1