zephyrCommon: Implement pulseIn

- A basic sync implementation
- Max precision of millisec. The actual arduino API seems to want microsec
  precision.

Signed-off-by: Ayush Singh <[email protected]>

Author: Ayush1325

cores/arduino/zephyrCommon.cpp

@@ -328,3 +328,26 @@ void detachInterrupt(pin_size_t pinNumber)
 {
   setInterruptHandler(pinNumber, nullptr);
 }
+
+unsigned long pulseIn(pin_size_t pinNumber, uint8_t state, unsigned long timeout) {
+	const struct gpio_dt_spec *spec = &arduino_pins[pinNumber];
+	int64_t start, delta;
+
+	if (!gpio_is_ready_dt(spec)) {
+		return 0;
+	}
+
+	if (!gpio_pin_is_input_dt(spec)) {
+		return 0;
+	}
+
+
+	while(gpio_pin_get_dt(spec) == state);
+	while(gpio_pin_get_dt(spec) != state);
+
+	start = k_uptime_get();
+	while(gpio_pin_get_dt(spec) == state);
+	delta = k_uptime_delta(&start);
+
+	return (unsigned long)(delta * USEC_PER_MSEC);
+}