gpio: pca953x: Make the irqchip immutable

Commit 6c846d0 ("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 pca953x driver:

    gpio gpiochip7: (0-0020): not an immutable chip, please consider fixing it!

Fix this by making the irqchip in the pca953x driver immutable.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>

Author: geertu

drivers/gpio/gpio-pca953x.c

@@ -201,7 +201,6 @@ struct pca953x_chip {
 	DECLARE_BITMAP(irq_stat, MAX_LINE);
 	DECLARE_BITMAP(irq_trig_raise, MAX_LINE);
 	DECLARE_BITMAP(irq_trig_fall, MAX_LINE);
-	struct irq_chip irq_chip;
 #endif
 	atomic_t wakeup_path;
 
@@ -629,6 +628,7 @@ static void pca953x_irq_mask(struct irq_data *d)
 	irq_hw_number_t hwirq = irqd_to_hwirq(d);
 
 	clear_bit(hwirq, chip->irq_mask);
+	gpiochip_disable_irq(gc, hwirq);
 }
 
 static void pca953x_irq_unmask(struct irq_data *d)
@@ -637,6 +637,7 @@ static void pca953x_irq_unmask(struct irq_data *d)
 	struct pca953x_chip *chip = gpiochip_get_data(gc);
 	irq_hw_number_t hwirq = irqd_to_hwirq(d);
 
+	gpiochip_enable_irq(gc, hwirq);
 	set_bit(hwirq, chip->irq_mask);
 }
 
@@ -721,6 +722,26 @@ static void pca953x_irq_shutdown(struct irq_data *d)
 	clear_bit(hwirq, chip->irq_trig_fall);
 }
 
+static void pca953x_irq_print_chip(struct irq_data *data, struct seq_file *p)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
+
+	seq_printf(p, dev_name(gc->parent));
+}
+
+static const struct irq_chip pca953x_irq_chip = {
+	.irq_mask		= pca953x_irq_mask,
+	.irq_unmask		= pca953x_irq_unmask,
+	.irq_set_wake		= pca953x_irq_set_wake,
+	.irq_bus_lock		= pca953x_irq_bus_lock,
+	.irq_bus_sync_unlock	= pca953x_irq_bus_sync_unlock,
+	.irq_set_type		= pca953x_irq_set_type,
+	.irq_shutdown		= pca953x_irq_shutdown,
+	.irq_print_chip		= pca953x_irq_print_chip,
+	.flags			= IRQCHIP_IMMUTABLE,
+	GPIOCHIP_IRQ_RESOURCE_HELPERS,
+};
+
 static bool pca953x_irq_pending(struct pca953x_chip *chip, unsigned long *pending)
 {
 	struct gpio_chip *gc = &chip->gpio_chip;
@@ -812,7 +833,6 @@ static irqreturn_t pca953x_irq_handler(int irq, void *devid)
 static int pca953x_irq_setup(struct pca953x_chip *chip, int irq_base)
 {
 	struct i2c_client *client = chip->client;
-	struct irq_chip *irq_chip = &chip->irq_chip;
 	DECLARE_BITMAP(reg_direction, MAX_LINE);
 	DECLARE_BITMAP(irq_stat, MAX_LINE);
 	struct gpio_irq_chip *girq;
@@ -846,17 +866,8 @@ static int pca953x_irq_setup(struct pca953x_chip *chip, int irq_base)
 	bitmap_and(chip->irq_stat, irq_stat, reg_direction, chip->gpio_chip.ngpio);
 	mutex_init(&chip->irq_lock);
 
-	irq_chip->name = dev_name(&client->dev);
-	irq_chip->irq_mask = pca953x_irq_mask;
-	irq_chip->irq_unmask = pca953x_irq_unmask;
-	irq_chip->irq_set_wake = pca953x_irq_set_wake;
-	irq_chip->irq_bus_lock = pca953x_irq_bus_lock;
-	irq_chip->irq_bus_sync_unlock = pca953x_irq_bus_sync_unlock;
-	irq_chip->irq_set_type = pca953x_irq_set_type;
-	irq_chip->irq_shutdown = pca953x_irq_shutdown;
-
 	girq = &chip->gpio_chip.irq;
-	girq->chip = irq_chip;
+	gpio_irq_chip_set_chip(girq, &pca953x_irq_chip);
 	/* This will let us handle the parent IRQ in the driver */
 	girq->parent_handler = NULL;
 	girq->num_parents = 0;