rtic-monotonics: Simplify features, default is 1kHz

Make 100 Hz or 10 kHz opt in through features,
which are meant for testing primarily.

1 files changed, 16 insertions, 9 deletions

diff --git a/rtic-monotonics/src/systick_monotonic.rs b/rtic-monotonics/src/systick_monotonic.rs
index a5a0aef..885da92 100644
--- a/rtic-monotonics/src/systick_monotonic.rs
+++ b/rtic-monotonics/src/systick_monotonic.rs
@@ -8,16 +8,23 @@ use cortex_m::peripheral::SYST;
 use embedded_hal_async::delay::DelayUs;
 pub use fugit::ExtU32;
 
-#[cfg(feature = "systick_100hz")]
-const TIMER_HZ: u32 = 100;
-
-#[cfg(feature = "systick_1khz")]
-const TIMER_HZ: u32 = 1_000;
-
-#[cfg(feature = "systick_10khz")]
-const TIMER_HZ: u32 = 10_000;
+// Features should be additive, here systick_100hz gets picked if both
+// `systick_100hz` and `systick_10khz` are enabled.
+
+cfg_if::cfg_if! {
+    if #[cfg(feature = "systick_100hz")]
+    {
+        const TIMER_HZ: u32 = 100;
+    } else if #[cfg(feature = "systick_10khz")]
+    {
+        const TIMER_HZ: u32 = 10_000;
+    } else {
+        // Default case is 1 kHz
+        const TIMER_HZ: u32 = 1_000;
+    }
+}
 
-/// Systick implementing `rtic_monotonic::Monotonic` which runs at 1 kHz.
+/// Systick implementing `rtic_monotonic::Monotonic` which runs at 1 kHz, 100Hz or 10 kHz.
 pub struct Systick;
 
 impl Systick {