Merge #617

617: Add feature defmt-timestamp-uptime r=Dirbaio a=danielzfranklin

Add the feature defmt-timestamp-uptime. Enabling it adds a timestamp of the number of seconds since startup next to defmt log messages using `Instant::now`.

Co-authored-by: Daniel Franklin <daniel@danielzfranklin.org>

embassy/Cargo.toml

@@ -17,6 +17,10 @@ nightly = ["embedded-hal-async"]
 # Implement embedded-hal-async traits if `nightly` is set as well.
 unstable-traits = ["embedded-hal-1"]
 
+# Display a timestamp of the number of seconds since startup next to defmt log messages
+# To use this you must have a time driver provided.
+defmt-timestamp-uptime = ["defmt"]
+
 # Enable `embassy::time` module. 
 # NOTE: This feature is only intended to be enabled by crates providing the time driver implementation.
 # Enabling it directly without supplying a time driver will fail to link.

embassy/src/fmt.rs

@@ -195,6 +195,9 @@ macro_rules! unwrap {
     }
 }
 
+#[cfg(feature = "defmt-timestamp-uptime")]
+defmt::timestamp! {"{=u64:us}", crate::time::Instant::now().as_micros() }
+
 #[derive(Debug, Copy, Clone, Eq, PartialEq)]
 pub struct NoneError;
 

embassy/src/time/instant.rs

@@ -28,6 +28,13 @@ impl Instant {
         Self { ticks }
     }
 
+    /// Create an Instant from a microsecond count since system boot.
+    pub const fn from_micros(micros: u64) -> Self {
+        Self {
+            ticks: micros * TICKS_PER_SECOND / 1_000_000,
+        }
+    }
+
     /// Create an Instant from a millisecond count since system boot.
     pub const fn from_millis(millis: u64) -> Self {
         Self {
@@ -57,6 +64,11 @@ impl Instant {
         self.ticks * 1000 / TICKS_PER_SECOND
     }
 
+    /// Microseconds since system boot.
+    pub const fn as_micros(&self) -> u64 {
+        self.ticks * 1_000_000 / TICKS_PER_SECOND
+    }
+
     /// Duration between this Instant and another Instant
     /// Panics on over/underflow.
     pub fn duration_since(&self, earlier: Instant) -> Duration {