gpio: mt7621: use the generic GPIO chip lock for IRQ handling

This driver uses its own 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 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-v2-9-f3d1a4c57124@linaro.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Author: Bartosz Golaszewski

drivers/gpio/gpio-mt7621.c

@@ -11,7 +11,6 @@
 #include <linux/io.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
-#include <linux/spinlock.h>
 
 #define MTK_BANK_CNT	3
 #define MTK_BANK_WIDTH	32
@@ -32,7 +31,6 @@
 struct mtk_gc {
 	struct irq_chip irq_chip;
 	struct gpio_generic_chip chip;
-	spinlock_t lock;
 	int bank;
 	u32 rising;
 	u32 falling;
@@ -111,12 +109,12 @@ mediatek_gpio_irq_unmask(struct irq_data *d)
 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
 	struct mtk_gc *rg = to_mediatek_gpio(gc);
 	int pin = d->hwirq;
-	unsigned long flags;
 	u32 rise, fall, high, low;
 
 	gpiochip_enable_irq(gc, d->hwirq);
 
-	spin_lock_irqsave(&rg->lock, flags);
+	guard(gpio_generic_lock_irqsave)(&rg->chip);
+
 	rise = mtk_gpio_r32(rg, GPIO_REG_REDGE);
 	fall = mtk_gpio_r32(rg, GPIO_REG_FEDGE);
 	high = mtk_gpio_r32(rg, GPIO_REG_HLVL);
@@ -125,7 +123,6 @@ mediatek_gpio_irq_unmask(struct irq_data *d)
 	mtk_gpio_w32(rg, GPIO_REG_FEDGE, fall | (BIT(pin) & rg->falling));
 	mtk_gpio_w32(rg, GPIO_REG_HLVL, high | (BIT(pin) & rg->hlevel));
 	mtk_gpio_w32(rg, GPIO_REG_LLVL, low | (BIT(pin) & rg->llevel));
-	spin_unlock_irqrestore(&rg->lock, flags);
 }
 
 static void
@@ -134,19 +131,18 @@ mediatek_gpio_irq_mask(struct irq_data *d)
 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
 	struct mtk_gc *rg = to_mediatek_gpio(gc);
 	int pin = d->hwirq;
-	unsigned long flags;
 	u32 rise, fall, high, low;
 
-	spin_lock_irqsave(&rg->lock, flags);
-	rise = mtk_gpio_r32(rg, GPIO_REG_REDGE);
-	fall = mtk_gpio_r32(rg, GPIO_REG_FEDGE);
-	high = mtk_gpio_r32(rg, GPIO_REG_HLVL);
-	low = mtk_gpio_r32(rg, GPIO_REG_LLVL);
-	mtk_gpio_w32(rg, GPIO_REG_FEDGE, fall & ~BIT(pin));
-	mtk_gpio_w32(rg, GPIO_REG_REDGE, rise & ~BIT(pin));
-	mtk_gpio_w32(rg, GPIO_REG_HLVL, high & ~BIT(pin));
-	mtk_gpio_w32(rg, GPIO_REG_LLVL, low & ~BIT(pin));
-	spin_unlock_irqrestore(&rg->lock, flags);
+	scoped_guard(gpio_generic_lock_irqsave, &rg->chip) {
+		rise = mtk_gpio_r32(rg, GPIO_REG_REDGE);
+		fall = mtk_gpio_r32(rg, GPIO_REG_FEDGE);
+		high = mtk_gpio_r32(rg, GPIO_REG_HLVL);
+		low = mtk_gpio_r32(rg, GPIO_REG_LLVL);
+		mtk_gpio_w32(rg, GPIO_REG_FEDGE, fall & ~BIT(pin));
+		mtk_gpio_w32(rg, GPIO_REG_REDGE, rise & ~BIT(pin));
+		mtk_gpio_w32(rg, GPIO_REG_HLVL, high & ~BIT(pin));
+		mtk_gpio_w32(rg, GPIO_REG_LLVL, low & ~BIT(pin));
+	}
 
 	gpiochip_disable_irq(gc, d->hwirq);
 }
@@ -232,7 +228,6 @@ mediatek_gpio_bank_probe(struct device *dev, int bank)
 	rg = &mtk->gc_map[bank];
 	memset(rg, 0, sizeof(*rg));
 
-	spin_lock_init(&rg->lock);
 	rg->bank = bank;
 
 	dat = mtk->base + GPIO_REG_DATA + (rg->bank * GPIO_BANK_STRIDE);