fix: Warnings and formatting all fixed

3 files changed, 45 insertions, 15 deletions

diff --git a/embassy-stm32/src/timer/low_level.rs b/embassy-stm32/src/timer/low_level.rs
index 2cee5f1f5..d1cf11386 100644
--- a/embassy-stm32/src/timer/low_level.rs
+++ b/embassy-stm32/src/timer/low_level.rs
@@ -812,8 +812,6 @@ impl<'d, T: GeneralInstance4Channel> Timer<'d, T> {
     /// You may want to start this in a new thread as this will block forever
 
     pub async fn waveform_continuous<C: TimerChannel>(&mut self, dma: Peri<'_, impl super::Dma<T, C>>, duty: &[u16]) {
-
-
         use crate::pac::timer::vals::Ccds;
 
         #[allow(clippy::let_unit_value)] // eg. stm32f334
@@ -855,7 +853,7 @@ impl<'d, T: GeneralInstance4Channel> Timer<'d, T> {
         req: dma::Request,
         channel: Channel,
         duty: &[u16],
-        circular: bool,
+        #[allow(unused_variables)] circular: bool,
     ) {
         let original_duty_state = self.get_compare_value(channel);
         let original_enable_state = self.get_channel_enable_state(channel);
diff --git a/embassy-stm32/src/timer/ringbuffered.rs b/embassy-stm32/src/timer/ringbuffered.rs
index bb602f8a7..e8f97bf59 100644
--- a/embassy-stm32/src/timer/ringbuffered.rs
+++ b/embassy-stm32/src/timer/ringbuffered.rs
@@ -5,9 +5,24 @@ use core::task::Waker;
 
 use super::low_level::Timer;
 use super::{Channel, GeneralInstance4Channel};
-use crate::dma::ringbuffer::Error;
 use crate::dma::WritableRingBuffer;
+use crate::dma::ringbuffer::Error;
 
+/// A PWM channel that uses a DMA ring buffer for continuous waveform generation.
+///
+/// This allows you to continuously update PWM duty cycles via DMA without blocking the CPU.
+/// The ring buffer enables smooth, uninterrupted waveform generation by automatically cycling
+/// through duty cycle values stored in memory.
+///
+/// You can write new duty cycle values to the ring buffer while it's running, enabling
+/// dynamic waveform generation for applications like motor control, LED dimming, or audio output.
+///
+/// # Example
+/// ```ignore
+/// let mut channel = pwm.ch1().into_ring_buffered_channel(dma_ch, &mut buffer);
+/// channel.start(); // Start DMA transfer
+/// channel.write(&[100, 200, 300]).ok(); // Update duty cycles
+/// ```
 pub struct RingBufferedPwmChannel<'d, T: GeneralInstance4Channel> {
     timer: ManuallyDrop<Timer<'d, T>>,
     ring_buf: WritableRingBuffer<'d, u16>,
@@ -15,7 +30,11 @@ pub struct RingBufferedPwmChannel<'d, T: GeneralInstance4Channel> {
 }
 
 impl<'d, T: GeneralInstance4Channel> RingBufferedPwmChannel<'d, T> {
-    pub(crate) fn new(timer: ManuallyDrop<Timer<'d, T>>, channel: Channel, ring_buf: WritableRingBuffer<'d, u16>) -> Self {
+    pub(crate) fn new(
+        timer: ManuallyDrop<Timer<'d, T>>,
+        channel: Channel,
+        ring_buf: WritableRingBuffer<'d, u16>,
+    ) -> Self {
         Self {
             timer,
             ring_buf,
@@ -148,5 +167,3 @@ pub struct RingBufferedPwmChannels<'d, T: GeneralInstance4Channel> {
     /// Channel 4
     pub ch4: RingBufferedPwmChannel<'d, T>,
 }
-
-
diff --git a/embassy-stm32/src/timer/simple_pwm.rs b/embassy-stm32/src/timer/simple_pwm.rs
index 53e0345ea..f4656b7bd 100644
--- a/embassy-stm32/src/timer/simple_pwm.rs
+++ b/embassy-stm32/src/timer/simple_pwm.rs
@@ -6,11 +6,11 @@ use core::mem::ManuallyDrop;
 use super::low_level::{CountingMode, OutputCompareMode, OutputPolarity, Timer};
 use super::ringbuffered::RingBufferedPwmChannel;
 use super::{Ch1, Ch2, Ch3, Ch4, Channel, GeneralInstance4Channel, TimerChannel, TimerPin};
-use crate::dma::WritableRingBuffer;
 use crate::Peri;
+use crate::dma::TransferOptions;
+use crate::dma::WritableRingBuffer;
 #[cfg(not(any(bdma, gpdma)))]
 use crate::dma::{Burst, FifoThreshold};
-use crate::dma::TransferOptions;
 #[cfg(gpio_v2)]
 use crate::gpio::Pull;
 use crate::gpio::{AfType, AnyPin, OutputType, Speed};
@@ -379,9 +379,27 @@ impl<'d, T: GeneralInstance4Channel> SimplePwm<'d, T> {
     pub async fn waveform_continuous<C: TimerChannel>(&mut self, dma: Peri<'_, impl super::Dma<T, C>>, duty: &[u16]) {
         self.inner.waveform_continuous(dma, duty).await;
     }
-    pub fn into_ring_buffered_channel<C: TimerChannel>(self, tx_dma: Peri<'d, impl super::Dma<T, C>>, dma_buf: &'d mut [u16]) -> RingBufferedPwmChannel<'d, T> {
+
+    /// Convert this PWM channel into a ring-buffered PWM channel.
+    ///
+    /// This allows continuous PWM waveform generation using a DMA ring buffer.
+    /// The ring buffer enables dynamic updates to the PWM duty cycle without blocking.
+    ///
+    /// # Arguments
+    /// * `tx_dma` - The DMA channel to use for transferring duty cycle values
+    /// * `dma_buf` - The buffer to use as a ring buffer (must be non-empty and <= 65535 elements)
+    ///
+    /// # Panics
+    /// Panics if `dma_buf` is empty or longer than 65535 elements.
+    pub fn into_ring_buffered_channel<C: TimerChannel>(
+        self,
+        tx_dma: Peri<'d, impl super::Dma<T, C>>,
+        dma_buf: &'d mut [u16],
+    ) -> RingBufferedPwmChannel<'d, T> {
         assert!(!dma_buf.is_empty() && dma_buf.len() <= 0xFFFF);
 
+        use crate::pac::timer::vals::Ccds;
+
         let channel = C::CHANNEL;
         let request = tx_dma.request();
 
@@ -393,6 +411,7 @@ impl<'d, T: GeneralInstance4Channel> SimplePwm<'d, T> {
             ..Default::default()
         };
 
+        self.inner.set_cc_dma_selection(Ccds::ON_UPDATE);
         let ring_buf = unsafe {
             WritableRingBuffer::new(
                 tx_dma,
@@ -403,11 +422,7 @@ impl<'d, T: GeneralInstance4Channel> SimplePwm<'d, T> {
             )
         };
 
-        RingBufferedPwmChannel::new(
-            unsafe { self.inner.clone_unchecked() },
-            channel,
-            ring_buf
-        )
+        RingBufferedPwmChannel::new(unsafe { self.inner.clone_unchecked() }, channel, ring_buf)
     }
 }