kaptan-actuator: improve config abstractions

Signed-off-by: Onur Özkan <work@onurozkan.dev>

libs/kaptan-actuator/src/dshot.rs

@@ -1,11 +1,48 @@
 //! DShot framing, timing, and arming policy.
 
+use crate::ArmingDuration;
 use core::sync::atomic::{AtomicBool, AtomicU16, Ordering};
 
 pub const MIN_THROTTLE: u16 = 48;
 pub const MOTOR_STOP: u16 = 0;
 pub const FRAME_SYMBOLS: usize = 18;
 
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+pub struct Config {
+    rate: Rate,
+    armed_idle_throttle: Throttle,
+    arming_duration: ArmingDuration,
+}
+
+impl Config {
+    pub const fn new(
+        rate: Rate,
+        armed_idle_throttle: Throttle,
+        arming_duration: ArmingDuration,
+    ) -> Option<Self> {
+        if rate.frames_for_millis(arming_duration.milliseconds()) == 0 {
+            return None;
+        }
+        Some(Self {
+            rate,
+            armed_idle_throttle,
+            arming_duration,
+        })
+    }
+
+    pub const fn rate(self) -> Rate {
+        self.rate
+    }
+
+    pub const fn armed_idle_throttle(self) -> Throttle {
+        self.armed_idle_throttle
+    }
+
+    pub const fn arming_duration(self) -> ArmingDuration {
+        self.arming_duration
+    }
+}
+
 #[derive(Clone, Copy, Debug, Eq, PartialEq)]
 pub enum Rate {
     Dshot150,
@@ -186,7 +223,8 @@ pub const fn symbols(packet: u16, zero_high: u16, one_high: u16) -> [u16; FRAME_
 
 #[cfg(test)]
 mod tests {
-    use super::{ArmSequence, FrameValue, Rate, Throttle, Timing, packet, symbols};
+    use super::{ArmSequence, Config, FrameValue, Rate, Throttle, Timing, packet, symbols};
+    use crate::ArmingDuration;
 
     #[test]
     fn packet_matches_standard_dshot_vectors() {
@@ -219,4 +257,11 @@ mod tests {
             assert!(Timing::from_timer_clock(rate.timer_base_hz(), rate).is_some());
         }
     }
+
+    #[test]
+    fn requires_an_arming_interval_with_frames() {
+        let duration = ArmingDuration::from_millis(2_000).unwrap();
+        let throttle = Throttle::new(300).unwrap();
+        assert!(Config::new(Rate::Dshot600, throttle, duration).is_some());
+    }
 }