MCUXpresso: Fix the LPC GPIO IRQ driver

The IRQ disable was always disabling both rising
and falling edges of the interrupt thereby causing
failures in cases when one of the two should stay enabled.

Signed-off-by: Mahesh Mahadevan <[email protected]>

Author: mmahadevan108

targets/TARGET_NXP/TARGET_MCUXpresso_MCUS/TARGET_LPC/gpio_irq_api.c

@@ -67,6 +67,13 @@ int gpio_irq_init(gpio_irq_t *obj, PinName pin, gpio_irq_handler handler, uint32
         return -1;
     }
 
+    obj->pin = pin & 0x1F;
+    obj->port = pin / 32;
+
+    if (obj->port >= INTERRUPT_PORTS) {
+        return -1;
+    }
+
     irq_handler = handler;
 
     for (i = 0; i < NUMBER_OF_GPIO_INTS; i++) {
@@ -82,13 +89,6 @@ int gpio_irq_init(gpio_irq_t *obj, PinName pin, gpio_irq_handler handler, uint32
         return -1;
     }
 
-    obj->pin = pin & 0x1F;
-    obj->port = pin / 32;
-
-    if (obj->port >= INTERRUPT_PORTS) {
-        return -1;
-    }
-
     /* Connect trigger sources to PINT */
     INPUTMUX_Init(INPUTMUX);
 
@@ -139,7 +139,26 @@ void gpio_irq_set(gpio_irq_t *obj, gpio_irq_event event, uint32_t enable)
             }
         }
     } else {
-        PINT_PinInterruptConfig(PINT, (pint_pin_int_t)obj->ch, kPINT_PinIntEnableNone, NULL);
+        if (event == IRQ_RISE) {
+            /* Checking if falling edge interrupt is already enabled on this pin */
+            if (PINT->IENF & (1U << obj->ch)) {
+                /* Leave falling edge interrupt enabled */
+                PINT_PinInterruptConfig(PINT, (pint_pin_int_t)obj->ch, kPINT_PinIntEnableFallEdge, pint_intr_callback);
+            } else {
+                /* Both rising and falling edge interrupt are disabled */
+                PINT_PinInterruptConfig(PINT, (pint_pin_int_t)obj->ch, kPINT_PinIntEnableNone, pint_intr_callback);
+            }
+        } else {
+            /* Checking if rising edge interrupt is already enabled on this pin */
+            if (PINT->IENR & (1U << obj->ch)) {
+                /* Leave rising edge interrupt enabled */
+                PINT_PinInterruptConfig(PINT, (pint_pin_int_t)obj->ch, kPINT_PinIntEnableRiseEdge, pint_intr_callback);
+            } else {
+                /* Both rising and falling edge interrupt are disabled */
+                PINT_PinInterruptConfig(PINT, (pint_pin_int_t)obj->ch, kPINT_PinIntEnableNone, pint_intr_callback);
+            }
+        }
+
     }
 }