pinctrl: npcm7xx: Convert to immutable irq_chip

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

I refactored the way the state container was accessed in
the irq_chip callbacks to all look the same and switch to
use irqd_to_hwirq() while we are at it.

Cc: Marc Zyngier <maz@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20230403-immutable-irqchips-v1-4-503788a7f6e6@linaro.org

Author: Linus Walleij

drivers/pinctrl/nuvoton/pinctrl-npcm7xx.c

@@ -82,7 +82,6 @@ struct npcm7xx_gpio {
 	struct gpio_chip	gc;
 	int			irqbase;
 	int			irq;
-	struct irq_chip		irq_chip;
 	u32			pinctrl_id;
 	int (*direction_input)(struct gpio_chip *chip, unsigned int offset);
 	int (*direction_output)(struct gpio_chip *chip, unsigned int offset,
@@ -240,9 +239,9 @@ static void npcmgpio_irq_handler(struct irq_desc *desc)
 
 static int npcmgpio_set_irq_type(struct irq_data *d, unsigned int type)
 {
-	struct npcm7xx_gpio *bank =
-		gpiochip_get_data(irq_data_get_irq_chip_data(d));
-	unsigned int gpio = BIT(d->hwirq);
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct npcm7xx_gpio *bank = gpiochip_get_data(gc);
+	unsigned int gpio = BIT(irqd_to_hwirq(d));
 
 	dev_dbg(bank->gc.parent, "setirqtype: %u.%u = %u\n", gpio,
 		d->irq, type);
@@ -288,9 +287,9 @@ static int npcmgpio_set_irq_type(struct irq_data *d, unsigned int type)
 
 static void npcmgpio_irq_ack(struct irq_data *d)
 {
-	struct npcm7xx_gpio *bank =
-		gpiochip_get_data(irq_data_get_irq_chip_data(d));
-	unsigned int gpio = d->hwirq;
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct npcm7xx_gpio *bank = gpiochip_get_data(gc);
+	unsigned int gpio = irqd_to_hwirq(d);
 
 	dev_dbg(bank->gc.parent, "irq_ack: %u.%u\n", gpio, d->irq);
 	iowrite32(BIT(gpio), bank->base + NPCM7XX_GP_N_EVST);
@@ -299,31 +298,33 @@ static void npcmgpio_irq_ack(struct irq_data *d)
 /* Disable GPIO interrupt */
 static void npcmgpio_irq_mask(struct irq_data *d)
 {
-	struct npcm7xx_gpio *bank =
-		gpiochip_get_data(irq_data_get_irq_chip_data(d));
-	unsigned int gpio = d->hwirq;
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct npcm7xx_gpio *bank = gpiochip_get_data(gc);
+	unsigned int gpio = irqd_to_hwirq(d);
 
 	/* Clear events */
 	dev_dbg(bank->gc.parent, "irq_mask: %u.%u\n", gpio, d->irq);
 	iowrite32(BIT(gpio), bank->base + NPCM7XX_GP_N_EVENC);
+	gpiochip_disable_irq(gc, gpio);
 }
 
 /* Enable GPIO interrupt */
 static void npcmgpio_irq_unmask(struct irq_data *d)
 {
-	struct npcm7xx_gpio *bank =
-		gpiochip_get_data(irq_data_get_irq_chip_data(d));
-	unsigned int gpio = d->hwirq;
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct npcm7xx_gpio *bank = gpiochip_get_data(gc);
+	unsigned int gpio = irqd_to_hwirq(d);
 
 	/* Enable events */
+	gpiochip_enable_irq(gc, gpio);
 	dev_dbg(bank->gc.parent, "irq_unmask: %u.%u\n", gpio, d->irq);
 	iowrite32(BIT(gpio), bank->base + NPCM7XX_GP_N_EVENS);
 }
 
 static unsigned int npcmgpio_irq_startup(struct irq_data *d)
 {
 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
-	unsigned int gpio = d->hwirq;
+	unsigned int gpio = irqd_to_hwirq(d);
 
 	/* active-high, input, clear interrupt, enable interrupt */
 	dev_dbg(gc->parent, "startup: %u.%u\n", gpio, d->irq);
@@ -341,6 +342,8 @@ static const struct irq_chip npcmgpio_irqchip = {
 	.irq_mask = npcmgpio_irq_mask,
 	.irq_set_type = npcmgpio_set_irq_type,
 	.irq_startup = npcmgpio_irq_startup,
+	.flags = IRQCHIP_IMMUTABLE,
+	GPIOCHIP_IRQ_RESOURCE_HELPERS,
 };
 
 /* pinmux handing in the pinctrl driver*/
@@ -1906,7 +1909,6 @@ static int npcm7xx_gpio_of(struct npcm7xx_pinctrl *pctrl)
 			return -EINVAL;
 		}
 		pctrl->gpio_bank[id].irq = ret;
-		pctrl->gpio_bank[id].irq_chip = npcmgpio_irqchip;
 		pctrl->gpio_bank[id].irqbase = id * NPCM7XX_GPIO_PER_BANK;
 		pctrl->gpio_bank[id].pinctrl_id = args.args[0];
 		pctrl->gpio_bank[id].gc.base = args.args[1];
@@ -1941,7 +1943,7 @@ static int npcm7xx_gpio_register(struct npcm7xx_pinctrl *pctrl)
 		struct gpio_irq_chip *girq;
 
 		girq = &pctrl->gpio_bank[id].gc.irq;
-		girq->chip = &pctrl->gpio_bank[id].irq_chip;
+		gpio_irq_chip_set_chip(girq, &npcmgpio_irqchip);
 		girq->parent_handler = npcmgpio_irq_handler;
 		girq->num_parents = 1;
 		girq->parents = devm_kcalloc(pctrl->dev, 1,