[fiber] Guarantee minimum for durations < 1µs

src/modm/processing/fiber/functions.hpp

@@ -87,12 +87,20 @@ poll_for(std::chrono::duration<Rep, Period> sleep_duration, Function &&condition
 							  std::chrono::duration<Rep, std::milli>>,
 		modm::chrono::milli_clock, modm::chrono::micro_clock>;
 
+	// Ensure the sleep duration is at least 1 clock tick
+	using Duration = typename Clock::duration;
+	Duration clock_sleep_duration(std::chrono::duration_cast<Duration>(sleep_duration));
+	if constexpr (std::ratio_less_v<Period, typename Clock::period>) {
+		if (clock_sleep_duration == Duration(0))
+			clock_sleep_duration = Duration(1);
+	}
+
 	const auto start = Clock::now();
 	do {
 		modm::this_fiber::yield();
 		if (std::forward<Function>(condition)()) return true;
 	}
-	while((Clock::now() - start) <= sleep_duration);
+	while((Clock::now() - start) <= clock_sleep_duration);
 	return false;
 }