pinctrl: ocelot: Fix incorrect trigger of the interrupt.

The interrupt controller can detect only link changes. So in case an
external device generated a level based interrupt, then the interrupt
controller detected correctly the first edge. But the problem was that
the interrupt controller was detecting also the edge when the interrupt
was cleared. So it would generate another interrupt.
The fix for this is to clear the second interrupt but still check the
interrupt line status.

Fixes: c297561 ("pinctrl: ocelot: Fix interrupt controller")
Signed-off-by: Horatiu Vultur <[email protected]>
Tested-by: Michael Walle <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Linus Walleij <[email protected]>

Author: HoratiuVultur

drivers/pinctrl/pinctrl-ocelot.c

@@ -1864,19 +1864,28 @@ static void ocelot_irq_unmask_level(struct irq_data *data)
 	if (val & bit)
 		ack = true;
 
+	/* Try to clear any rising edges */
+	if (!active && ack)
+		regmap_write_bits(info->map, REG(OCELOT_GPIO_INTR, info, gpio),
+				  bit, bit);
+
 	/* Enable the interrupt now */
 	gpiochip_enable_irq(chip, gpio);
 	regmap_update_bits(info->map, REG(OCELOT_GPIO_INTR_ENA, info, gpio),
 			   bit, bit);
 
 	/*
-	 * In case the interrupt line is still active and the interrupt
-	 * controller has not seen any changes in the interrupt line, then it
-	 * means that there happen another interrupt while the line was active.
+	 * In case the interrupt line is still active then it means that
+	 * there happen another interrupt while the line was active.
 	 * So we missed that one, so we need to kick the interrupt again
 	 * handler.
 	 */
-	if (active && !ack) {
+	regmap_read(info->map, REG(OCELOT_GPIO_IN, info, gpio), &val);
+	if ((!(val & bit) && trigger_level == IRQ_TYPE_LEVEL_LOW) ||
+	      (val & bit && trigger_level == IRQ_TYPE_LEVEL_HIGH))
+		active = true;
+
+	if (active) {
 		struct ocelot_irq_work *work;
 
 		work = kmalloc(sizeof(*work), GFP_ATOMIC);