pinctrl: iproc: Convert to immutable irq_chip

Convert the driver to immutable irq-chip with a bit of
intuition.

Cc: Marc Zyngier <maz@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20230403-immutable-irqchips-v1-1-503788a7f6e6@linaro.org

Author: Linus Walleij

drivers/pinctrl/bcm/pinctrl-iproc-gpio.c

@@ -23,6 +23,7 @@
 #include <linux/kernel.h>
 #include <linux/of_device.h>
 #include <linux/of_irq.h>
+#include <linux/seq_file.h>
 #include <linux/slab.h>
 
 #include <linux/pinctrl/consumer.h>
@@ -108,7 +109,6 @@ struct iproc_gpio {
 
 	raw_spinlock_t lock;
 
-	struct irq_chip irqchip;
 	struct gpio_chip gc;
 	unsigned num_banks;
 
@@ -217,7 +217,7 @@ static void iproc_gpio_irq_set_mask(struct irq_data *d, bool unmask)
 {
 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
 	struct iproc_gpio *chip = gpiochip_get_data(gc);
-	unsigned gpio = d->hwirq;
+	unsigned gpio = irqd_to_hwirq(d);
 
 	iproc_set_bit(chip, IPROC_GPIO_INT_MSK_OFFSET, gpio, unmask);
 }
@@ -231,6 +231,7 @@ static void iproc_gpio_irq_mask(struct irq_data *d)
 	raw_spin_lock_irqsave(&chip->lock, flags);
 	iproc_gpio_irq_set_mask(d, false);
 	raw_spin_unlock_irqrestore(&chip->lock, flags);
+	gpiochip_disable_irq(gc, irqd_to_hwirq(d));
 }
 
 static void iproc_gpio_irq_unmask(struct irq_data *d)
@@ -239,6 +240,7 @@ static void iproc_gpio_irq_unmask(struct irq_data *d)
 	struct iproc_gpio *chip = gpiochip_get_data(gc);
 	unsigned long flags;
 
+	gpiochip_enable_irq(gc, irqd_to_hwirq(d));
 	raw_spin_lock_irqsave(&chip->lock, flags);
 	iproc_gpio_irq_set_mask(d, true);
 	raw_spin_unlock_irqrestore(&chip->lock, flags);
@@ -302,6 +304,26 @@ static int iproc_gpio_irq_set_type(struct irq_data *d, unsigned int type)
 	return 0;
 }
 
+static void iproc_gpio_irq_print_chip(struct irq_data *d, struct seq_file *p)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct iproc_gpio *chip = gpiochip_get_data(gc);
+
+	seq_printf(p, dev_name(chip->dev));
+}
+
+static const struct irq_chip iproc_gpio_irq_chip = {
+	.irq_ack = iproc_gpio_irq_ack,
+	.irq_mask = iproc_gpio_irq_mask,
+	.irq_unmask = iproc_gpio_irq_unmask,
+	.irq_set_type = iproc_gpio_irq_set_type,
+	.irq_enable = iproc_gpio_irq_unmask,
+	.irq_disable = iproc_gpio_irq_mask,
+	.irq_print_chip = iproc_gpio_irq_print_chip,
+	.flags = IRQCHIP_IMMUTABLE,
+	GPIOCHIP_IRQ_RESOURCE_HELPERS,
+};
+
 /*
  * Request the Iproc IOMUX pinmux controller to mux individual pins to GPIO
  */
@@ -852,20 +874,10 @@ static int iproc_gpio_probe(struct platform_device *pdev)
 	/* optional GPIO interrupt support */
 	irq = platform_get_irq_optional(pdev, 0);
 	if (irq > 0) {
-		struct irq_chip *irqc;
 		struct gpio_irq_chip *girq;
 
-		irqc = &chip->irqchip;
-		irqc->name = dev_name(dev);
-		irqc->irq_ack = iproc_gpio_irq_ack;
-		irqc->irq_mask = iproc_gpio_irq_mask;
-		irqc->irq_unmask = iproc_gpio_irq_unmask;
-		irqc->irq_set_type = iproc_gpio_irq_set_type;
-		irqc->irq_enable = iproc_gpio_irq_unmask;
-		irqc->irq_disable = iproc_gpio_irq_mask;
-
 		girq = &gc->irq;
-		girq->chip = irqc;
+		gpio_irq_chip_set_chip(girq, &iproc_gpio_irq_chip);
 		girq->parent_handler = iproc_gpio_irq_handler;
 		girq->num_parents = 1;
 		girq->parents = devm_kcalloc(dev, 1,