gpio: ath79: use the generic GPIO chip lock for IRQ handling

This driver uses its own raw spinlock in interrupt routines while the
generic GPIO chip callbacks use a separate one. This is, of course, racy
so use the fact that the lock in generic GPIO chip is also a raw
spinlock and convert the interrupt handling functions in this module to
using the provided generic GPIO chip locking API.

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20250910-gpio-mmio-gpio-conv-part4-v2-5-f3d1a4c57124@linaro.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Author: Bartosz Golaszewski

drivers/gpio/gpio-ath79.c

@@ -31,7 +31,6 @@
 struct ath79_gpio_ctrl {
 	struct gpio_generic_chip chip;
 	void __iomem *base;
-	raw_spinlock_t lock;
 	unsigned long both_edges;
 };
 
@@ -72,48 +71,43 @@ static void ath79_gpio_irq_unmask(struct irq_data *data)
 {
 	struct ath79_gpio_ctrl *ctrl = irq_data_to_ath79_gpio(data);
 	u32 mask = BIT(irqd_to_hwirq(data));
-	unsigned long flags;
 
 	gpiochip_enable_irq(&ctrl->chip.gc, irqd_to_hwirq(data));
-	raw_spin_lock_irqsave(&ctrl->lock, flags);
+
+	guard(gpio_generic_lock_irqsave)(&ctrl->chip);
+
 	ath79_gpio_update_bits(ctrl, AR71XX_GPIO_REG_INT_MASK, mask, mask);
-	raw_spin_unlock_irqrestore(&ctrl->lock, flags);
 }
 
 static void ath79_gpio_irq_mask(struct irq_data *data)
 {
 	struct ath79_gpio_ctrl *ctrl = irq_data_to_ath79_gpio(data);
 	u32 mask = BIT(irqd_to_hwirq(data));
-	unsigned long flags;
 
-	raw_spin_lock_irqsave(&ctrl->lock, flags);
-	ath79_gpio_update_bits(ctrl, AR71XX_GPIO_REG_INT_MASK, mask, 0);
-	raw_spin_unlock_irqrestore(&ctrl->lock, flags);
+	scoped_guard(gpio_generic_lock_irqsave, &ctrl->chip)
+		ath79_gpio_update_bits(ctrl, AR71XX_GPIO_REG_INT_MASK, mask, 0);
+
 	gpiochip_disable_irq(&ctrl->chip.gc, irqd_to_hwirq(data));
 }
 
 static void ath79_gpio_irq_enable(struct irq_data *data)
 {
 	struct ath79_gpio_ctrl *ctrl = irq_data_to_ath79_gpio(data);
 	u32 mask = BIT(irqd_to_hwirq(data));
-	unsigned long flags;
 
-	raw_spin_lock_irqsave(&ctrl->lock, flags);
+	guard(gpio_generic_lock_irqsave)(&ctrl->chip);
 	ath79_gpio_update_bits(ctrl, AR71XX_GPIO_REG_INT_ENABLE, mask, mask);
 	ath79_gpio_update_bits(ctrl, AR71XX_GPIO_REG_INT_MASK, mask, mask);
-	raw_spin_unlock_irqrestore(&ctrl->lock, flags);
 }
 
 static void ath79_gpio_irq_disable(struct irq_data *data)
 {
 	struct ath79_gpio_ctrl *ctrl = irq_data_to_ath79_gpio(data);
 	u32 mask = BIT(irqd_to_hwirq(data));
-	unsigned long flags;
 
-	raw_spin_lock_irqsave(&ctrl->lock, flags);
+	guard(gpio_generic_lock_irqsave)(&ctrl->chip);
 	ath79_gpio_update_bits(ctrl, AR71XX_GPIO_REG_INT_MASK, mask, 0);
 	ath79_gpio_update_bits(ctrl, AR71XX_GPIO_REG_INT_ENABLE, mask, 0);
-	raw_spin_unlock_irqrestore(&ctrl->lock, flags);
 }
 
 static int ath79_gpio_irq_set_type(struct irq_data *data,
@@ -122,7 +116,6 @@ static int ath79_gpio_irq_set_type(struct irq_data *data,
 	struct ath79_gpio_ctrl *ctrl = irq_data_to_ath79_gpio(data);
 	u32 mask = BIT(irqd_to_hwirq(data));
 	u32 type = 0, polarity = 0;
-	unsigned long flags;
 	bool disabled;
 
 	switch (flow_type) {
@@ -144,7 +137,7 @@ static int ath79_gpio_irq_set_type(struct irq_data *data,
 		return -EINVAL;
 	}
 
-	raw_spin_lock_irqsave(&ctrl->lock, flags);
+	guard(gpio_generic_lock_irqsave)(&ctrl->chip);
 
 	if (flow_type == IRQ_TYPE_EDGE_BOTH) {
 		ctrl->both_edges |= mask;
@@ -169,8 +162,6 @@ static int ath79_gpio_irq_set_type(struct irq_data *data,
 		ath79_gpio_update_bits(
 			ctrl, AR71XX_GPIO_REG_INT_ENABLE, mask, mask);
 
-	raw_spin_unlock_irqrestore(&ctrl->lock, flags);
-
 	return 0;
 }
 
@@ -192,26 +183,24 @@ static void ath79_gpio_irq_handler(struct irq_desc *desc)
 	struct gpio_generic_chip *gen_gc = to_gpio_generic_chip(gc);
 	struct ath79_gpio_ctrl *ctrl =
 		container_of(gen_gc, struct ath79_gpio_ctrl, chip);
-	unsigned long flags, pending;
+	unsigned long pending;
 	u32 both_edges, state;
 	int irq;
 
 	chained_irq_enter(irqchip, desc);
 
-	raw_spin_lock_irqsave(&ctrl->lock, flags);
-
-	pending = ath79_gpio_read(ctrl, AR71XX_GPIO_REG_INT_PENDING);
+	scoped_guard(gpio_generic_lock_irqsave, &ctrl->chip) {
+		pending = ath79_gpio_read(ctrl, AR71XX_GPIO_REG_INT_PENDING);
 
-	/* Update the polarity of the both edges irqs */
-	both_edges = ctrl->both_edges & pending;
-	if (both_edges) {
-		state = ath79_gpio_read(ctrl, AR71XX_GPIO_REG_IN);
-		ath79_gpio_update_bits(ctrl, AR71XX_GPIO_REG_INT_POLARITY,
-				both_edges, ~state);
+		/* Update the polarity of the both edges irqs */
+		both_edges = ctrl->both_edges & pending;
+		if (both_edges) {
+			state = ath79_gpio_read(ctrl, AR71XX_GPIO_REG_IN);
+			ath79_gpio_update_bits(ctrl, AR71XX_GPIO_REG_INT_POLARITY,
+					       both_edges, ~state);
+		}
 	}
 
-	raw_spin_unlock_irqrestore(&ctrl->lock, flags);
-
 	for_each_set_bit(irq, &pending, gc->ngpio)
 		generic_handle_domain_irq(gc->irq.domain, irq);
 
@@ -256,8 +245,6 @@ static int ath79_gpio_probe(struct platform_device *pdev)
 	if (IS_ERR(ctrl->base))
 		return PTR_ERR(ctrl->base);
 
-	raw_spin_lock_init(&ctrl->lock);
-
 	config = (struct gpio_generic_chip_config) {
 		.dev = dev,
 		.sz = 4,