diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index d0ea705..e8e0e4e 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -29,6 +29,7 @@ jobs:
       - uses: actions-rs/clippy-check@v1
         continue-on-error: true
         with:
+          toolchain: stable
           token: ${{ secrets.GITHUB_TOKEN }}
 
   compile:
diff --git a/dsp/src/pll.rs b/dsp/src/pll.rs
index 74377f3..8df750f 100644
--- a/dsp/src/pll.rs
+++ b/dsp/src/pll.rs
@@ -45,7 +45,7 @@ impl PLL {
     /// The signal's phase/frequency is reconstructed relative to the sampling period.
     ///
     /// Args:
-    /// * `input`: New input phase sample.
+    /// * `x`: New input phase sample.
     /// * `shift_frequency`: Frequency error scaling. The frequency gain per update is
     ///   `1/(1 << shift_frequency)`.
     /// * `shift_phase`: Phase error scaling. The phase gain is `1/(1 << shift_phase)`