zephyrCommon: Implement pulseIn

- A basic sync implementation
- Use ticks for better resolution

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

Author: Ayush1325

cores/arduino/zephyrCommon.cpp

@@ -328,3 +328,46 @@ void detachInterrupt(pin_size_t pinNumber)
 {
   setInterruptHandler(pinNumber, nullptr);
 }
+
+unsigned long pulseIn(pin_size_t pinNumber, uint8_t state, unsigned long timeout) {
+  struct k_timer timer;
+  int64_t start, end, delta = 0;
+  const struct gpio_dt_spec *spec = &arduino_pins[pinNumber];
+
+  k_timer_init(&timer, NULL, NULL);
+  k_timer_start(&timer, K_MSEC(timeout), K_NO_WAIT);
+
+  if (!gpio_is_ready_dt(spec)) {
+    goto cleanup;
+  }
+
+  if (!gpio_pin_is_input_dt(spec)) {
+    goto cleanup;
+  }
+
+  while(gpio_pin_get_dt(spec) == state) {
+    if (k_timer_status_get(&timer) > 0) {
+      goto cleanup;
+    }
+  }
+
+  while(gpio_pin_get_dt(spec) != state) {
+    if (k_timer_status_get(&timer) > 0) {
+      goto cleanup;
+    }
+  }
+
+  start = k_uptime_ticks();
+  while(gpio_pin_get_dt(spec) == state) {
+    if (k_timer_status_get(&timer) > 0) {
+      goto cleanup;
+    }
+  }
+  end = k_uptime_ticks();
+
+  delta = k_ticks_to_us_floor64(end - start);
+
+cleanup:
+  k_timer_stop(&timer);
+  return (unsigned long)delta;
+}