gpio: cadence: Add support for edge-triggered interrupts

The Cadence GPIO controller (CDNS IP6508) supports edge-triggered
interrupts (rising, falling, and both) via IRQ_TYPE, IRQ_VALUE,
and IRQ_ANY_EDGE registers. This commit enables support for these
modes in cdns_gpio_irq_set_type().

Although the interrupt status register is cleared on read and lacks
per-pin acknowledgment, the driver already handles this safely by
reading the ISR once and dispatching all pending interrupts immediately.
This allows edge IRQs to be used reliably in controlled environments.

Signed-off-by: Tzu-Hao Wei <[e-mail]>
Reviewed-by: Linus Walleij <[e-mail]>
Signed-off-by: Swark Yang <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Bartosz Golaszewski <[e-mail]>

drivers/gpio/gpio-cadence.c

···
 	struct cdns_gpio_chip *cgpio = gpiochip_get_data(chip);
 	u32 int_value;
 	u32 int_type;
+	u32 int_any;
 	u32 mask = BIT(d->hwirq);
 	int ret = 0;
 
···
 
 	int_value = ioread32(cgpio->regs + CDNS_GPIO_IRQ_VALUE) & ~mask;
 	int_type = ioread32(cgpio->regs + CDNS_GPIO_IRQ_TYPE) & ~mask;
-
 	/*
-	 * The GPIO controller doesn't have an ACK register.
-	 * All interrupt statuses are cleared on a status register read.
-	 * Don't support edge interrupts for now.
+	 * Interrupt polarity and trigger behaviour is configured like this:
+	 *
+	 * (type, value)
+	 * (0, 0) = Falling edge triggered
+	 * (0, 1) = Rising edge triggered
+	 * (1, 0) = Low level triggered
+	 * (1, 1) = High level triggered
 	 */
+	int_any = ioread32(cgpio->regs + CDNS_GPIO_IRQ_ANY_EDGE) & ~mask;
 
 	if (type == IRQ_TYPE_LEVEL_HIGH) {
 		int_type |= mask;
 		int_value |= mask;
 	} else if (type == IRQ_TYPE_LEVEL_LOW) {
 		int_type |= mask;
+	} else if (type == IRQ_TYPE_EDGE_RISING) {
+		int_value |= mask;
+	} else if (type == IRQ_TYPE_EDGE_FALLING) {
+		/* edge trigger, int_value remains cleared for falling */
+	} else if (type == IRQ_TYPE_EDGE_BOTH) {
+		int_any |= mask;
 	} else {
 		return -EINVAL;
 	}
 
 	iowrite32(int_value, cgpio->regs + CDNS_GPIO_IRQ_VALUE);
 	iowrite32(int_type, cgpio->regs + CDNS_GPIO_IRQ_TYPE);
+	iowrite32(int_any, cgpio->regs + CDNS_GPIO_IRQ_ANY_EDGE);
 
 	return ret;
 }