docs: document all embassy-rp public apis

Enable missing doc warnings.

embassy-rp/src/adc.rs

@@ -1,3 +1,4 @@
+//! ADC driver.
 use core::future::poll_fn;
 use core::marker::PhantomData;
 use core::mem;
@@ -16,6 +17,7 @@ use crate::{dma, interrupt, pac, peripherals, Peripheral, RegExt};
 
 static WAKER: AtomicWaker = AtomicWaker::new();
 
+/// ADC config.
 #[non_exhaustive]
 pub struct Config {}
 
@@ -30,9 +32,11 @@ enum Source<'p> {
     TempSensor(PeripheralRef<'p, ADC_TEMP_SENSOR>),
 }
 
+/// ADC channel.
 pub struct Channel<'p>(Source<'p>);
 
 impl<'p> Channel<'p> {
+    /// Create a new ADC channel from pin with the provided [Pull] configuration.
     pub fn new_pin(pin: impl Peripheral<P = impl AdcPin + 'p> + 'p, pull: Pull) -> Self {
         into_ref!(pin);
         pin.pad_ctrl().modify(|w| {
@@ -49,6 +53,7 @@ impl<'p> Channel<'p> {
         Self(Source::Pin(pin.map_into()))
     }
 
+    /// Create a new ADC channel for the internal temperature sensor.
     pub fn new_temp_sensor(s: impl Peripheral<P = ADC_TEMP_SENSOR> + 'p) -> Self {
         let r = pac::ADC;
         r.cs().write_set(|w| w.set_ts_en(true));
@@ -83,35 +88,44 @@ impl<'p> Drop for Source<'p> {
     }
 }
 
+/// ADC sample.
 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Debug, Default)]
 #[cfg_attr(feature = "defmt", derive(defmt::Format))]
 #[repr(transparent)]
 pub struct Sample(u16);
 
 impl Sample {
+    /// Sample is valid.
     pub fn good(&self) -> bool {
         self.0 < 0x8000
     }
 
+    /// Sample value.
     pub fn value(&self) -> u16 {
         self.0 & !0x8000
     }
 }
 
+/// ADC error.
 #[derive(Debug, Eq, PartialEq, Copy, Clone)]
 #[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub enum Error {
+    /// Error converting value.
     ConversionFailed,
 }
 
+/// ADC mode.
 pub trait Mode {}
 
+/// ADC async mode.
 pub struct Async;
 impl Mode for Async {}
 
+/// ADC blocking mode.
 pub struct Blocking;
 impl Mode for Blocking {}
 
+/// ADC driver.
 pub struct Adc<'d, M: Mode> {
     phantom: PhantomData<(&'d ADC, M)>,
 }
@@ -150,6 +164,7 @@ impl<'d, M: Mode> Adc<'d, M> {
         while !r.cs().read().ready() {}
     }
 
+    /// Sample a value from a channel in blocking mode.
     pub fn blocking_read(&mut self, ch: &mut Channel) -> Result<u16, Error> {
         let r = Self::regs();
         r.cs().modify(|w| {
@@ -166,6 +181,7 @@ impl<'d, M: Mode> Adc<'d, M> {
 }
 
 impl<'d> Adc<'d, Async> {
+    /// Create ADC driver in async mode.
     pub fn new(
         _inner: impl Peripheral<P = ADC> + 'd,
         _irq: impl Binding<interrupt::typelevel::ADC_IRQ_FIFO, InterruptHandler>,
@@ -194,6 +210,7 @@ impl<'d> Adc<'d, Async> {
         .await;
     }
 
+    /// Sample a value from a channel until completed.
     pub async fn read(&mut self, ch: &mut Channel<'_>) -> Result<u16, Error> {
         let r = Self::regs();
         r.cs().modify(|w| {
@@ -272,6 +289,7 @@ impl<'d> Adc<'d, Async> {
         }
     }
 
+    /// Sample multiple values from a channel using DMA.
     #[inline]
     pub async fn read_many<S: AdcSample>(
         &mut self,
@@ -283,6 +301,7 @@ impl<'d> Adc<'d, Async> {
         self.read_many_inner(ch, buf, false, div, dma).await
     }
 
+    /// Sample multiple values from a channel using DMA with errors inlined in samples.
     #[inline]
     pub async fn read_many_raw(
         &mut self,
@@ -299,6 +318,7 @@ impl<'d> Adc<'d, Async> {
 }
 
 impl<'d> Adc<'d, Blocking> {
+    /// Create ADC driver in blocking mode.
     pub fn new_blocking(_inner: impl Peripheral<P = ADC> + 'd, _config: Config) -> Self {
         Self::setup();
 
@@ -306,6 +326,7 @@ impl<'d> Adc<'d, Blocking> {
     }
 }
 
+/// Interrupt handler.
 pub struct InterruptHandler {
     _empty: (),
 }
@@ -324,6 +345,7 @@ mod sealed {
     pub trait AdcChannel {}
 }
 
+/// ADC sample.
 pub trait AdcSample: sealed::AdcSample {}
 
 impl sealed::AdcSample for u16 {}
@@ -332,7 +354,9 @@ impl AdcSample for u16 {}
 impl sealed::AdcSample for u8 {}
 impl AdcSample for u8 {}
 
+/// ADC channel.
 pub trait AdcChannel: sealed::AdcChannel {}
+/// ADC pin.
 pub trait AdcPin: AdcChannel + gpio::Pin {}
 
 macro_rules! impl_pin {

embassy-rp/src/clocks.rs

@@ -45,15 +45,20 @@ static CLOCKS: Clocks = Clocks {
     rtc: AtomicU16::new(0),
 };
 
-/// Enumeration of supported clock sources.
+/// Peripheral clock sources.
 #[repr(u8)]
 #[non_exhaustive]
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub enum PeriClkSrc {
+    /// SYS.
     Sys = ClkPeriCtrlAuxsrc::CLK_SYS as _,
+    /// PLL SYS.
     PllSys = ClkPeriCtrlAuxsrc::CLKSRC_PLL_SYS as _,
+    /// PLL USB.
     PllUsb = ClkPeriCtrlAuxsrc::CLKSRC_PLL_USB as _,
+    /// ROSC.
     Rosc = ClkPeriCtrlAuxsrc::ROSC_CLKSRC_PH as _,
+    /// XOSC.
     Xosc = ClkPeriCtrlAuxsrc::XOSC_CLKSRC as _,
     // Gpin0 = ClkPeriCtrlAuxsrc::CLKSRC_GPIN0 as _ ,
     // Gpin1 = ClkPeriCtrlAuxsrc::CLKSRC_GPIN1 as _ ,
@@ -83,6 +88,7 @@ pub struct ClockConfig {
 }
 
 impl ClockConfig {
+    /// Clock configuration derived from external crystal.
     pub fn crystal(crystal_hz: u32) -> Self {
         Self {
             rosc: Some(RoscConfig {
@@ -141,6 +147,7 @@ impl ClockConfig {
         }
     }
 
+    /// Clock configuration from internal oscillator.
     pub fn rosc() -> Self {
         Self {
             rosc: Some(RoscConfig {
@@ -190,13 +197,18 @@ impl ClockConfig {
     // }
 }
 
+/// ROSC freq range.
 #[repr(u16)]
 #[non_exhaustive]
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub enum RoscRange {
+    /// Low range.
     Low = pac::rosc::vals::FreqRange::LOW.0,
+    /// Medium range (1.33x low)
     Medium = pac::rosc::vals::FreqRange::MEDIUM.0,
+    /// High range (2x low)
     High = pac::rosc::vals::FreqRange::HIGH.0,
+    /// Too high. Should not be used.
     TooHigh = pac::rosc::vals::FreqRange::TOOHIGH.0,
 }
 
@@ -239,96 +251,136 @@ pub struct PllConfig {
     pub post_div2: u8,
 }
 
-/// Reference
+/// Reference clock config.
 pub struct RefClkConfig {
+    /// Reference clock source.
     pub src: RefClkSrc,
+    /// Reference clock divider.
     pub div: u8,
 }
 
+/// Reference clock source.
 #[non_exhaustive]
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub enum RefClkSrc {
-    // main sources
+    /// XOSC.
     Xosc,
+    /// ROSC.
     Rosc,
-    // aux sources
+    /// PLL USB.
     PllUsb,
     // Gpin0,
     // Gpin1,
 }
 
+/// SYS clock source.
 #[non_exhaustive]
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub enum SysClkSrc {
-    // main sources
+    /// REF.
     Ref,
-    // aux sources
+    /// PLL SYS.
     PllSys,
+    /// PLL USB.
     PllUsb,
+    /// ROSC.
     Rosc,
+    /// XOSC.
     Xosc,
     // Gpin0,
     // Gpin1,
 }
 
+/// SYS clock config.
 pub struct SysClkConfig {
+    /// SYS clock source.
     pub src: SysClkSrc,
+    /// SYS clock divider.
     pub div_int: u32,
+    /// SYS clock fraction.
     pub div_frac: u8,
 }
 
+/// USB clock source.
 #[repr(u8)]
 #[non_exhaustive]
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub enum UsbClkSrc {
+    /// PLL USB.
     PllUsb = ClkUsbCtrlAuxsrc::CLKSRC_PLL_USB as _,
+    /// PLL SYS.
     PllSys = ClkUsbCtrlAuxsrc::CLKSRC_PLL_SYS as _,
+    /// ROSC.
     Rosc = ClkUsbCtrlAuxsrc::ROSC_CLKSRC_PH as _,
+    /// XOSC.
     Xosc = ClkUsbCtrlAuxsrc::XOSC_CLKSRC as _,
     // Gpin0 = ClkUsbCtrlAuxsrc::CLKSRC_GPIN0 as _ ,
     // Gpin1 = ClkUsbCtrlAuxsrc::CLKSRC_GPIN1 as _ ,
 }
 
+/// USB clock config.
 pub struct UsbClkConfig {
+    /// USB clock source.
     pub src: UsbClkSrc,
+    /// USB clock divider.
     pub div: u8,
+    /// USB clock phase.
     pub phase: u8,
 }
 
+/// ADC clock source.
 #[repr(u8)]
 #[non_exhaustive]
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub enum AdcClkSrc {
+    /// PLL USB.
     PllUsb = ClkAdcCtrlAuxsrc::CLKSRC_PLL_USB as _,
+    /// PLL SYS.
     PllSys = ClkAdcCtrlAuxsrc::CLKSRC_PLL_SYS as _,
+    /// ROSC.
     Rosc = ClkAdcCtrlAuxsrc::ROSC_CLKSRC_PH as _,
+    /// XOSC.
     Xosc = ClkAdcCtrlAuxsrc::XOSC_CLKSRC as _,
     // Gpin0 = ClkAdcCtrlAuxsrc::CLKSRC_GPIN0 as _ ,
     // Gpin1 = ClkAdcCtrlAuxsrc::CLKSRC_GPIN1 as _ ,
 }
 
+/// ADC clock config.
 pub struct AdcClkConfig {
+    /// ADC clock source.
     pub src: AdcClkSrc,
+    /// ADC clock divider.
     pub div: u8,
+    /// ADC clock phase.
     pub phase: u8,
 }
 
+/// RTC clock source.
 #[repr(u8)]
 #[non_exhaustive]
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub enum RtcClkSrc {
+    /// PLL USB.
     PllUsb = ClkRtcCtrlAuxsrc::CLKSRC_PLL_USB as _,
+    /// PLL SYS.
     PllSys = ClkRtcCtrlAuxsrc::CLKSRC_PLL_SYS as _,
+    /// ROSC.
     Rosc = ClkRtcCtrlAuxsrc::ROSC_CLKSRC_PH as _,
+    /// XOSC.
     Xosc = ClkRtcCtrlAuxsrc::XOSC_CLKSRC as _,
     // Gpin0 = ClkRtcCtrlAuxsrc::CLKSRC_GPIN0 as _ ,
     // Gpin1 = ClkRtcCtrlAuxsrc::CLKSRC_GPIN1 as _ ,
 }
 
+/// RTC clock config.
 pub struct RtcClkConfig {
+    /// RTC clock source.
     pub src: RtcClkSrc,
+    /// RTC clock divider.
     pub div_int: u32,
+    /// RTC clock divider fraction.
     pub div_frac: u8,
+    /// RTC clock phase.
     pub phase: u8,
 }
 
@@ -605,10 +657,12 @@ fn configure_rosc(config: RoscConfig) -> u32 {
     config.hz
 }
 
+/// ROSC clock frequency.
 pub fn rosc_freq() -> u32 {
     CLOCKS.rosc.load(Ordering::Relaxed)
 }
 
+/// XOSC clock frequency.
 pub fn xosc_freq() -> u32 {
     CLOCKS.xosc.load(Ordering::Relaxed)
 }
@@ -620,34 +674,42 @@ pub fn xosc_freq() -> u32 {
 //     CLOCKS.gpin1.load(Ordering::Relaxed)
 // }
 
+/// PLL SYS clock frequency.
 pub fn pll_sys_freq() -> u32 {
     CLOCKS.pll_sys.load(Ordering::Relaxed)
 }
 
+/// PLL USB clock frequency.
 pub fn pll_usb_freq() -> u32 {
     CLOCKS.pll_usb.load(Ordering::Relaxed)
 }
 
+/// SYS clock frequency.
 pub fn clk_sys_freq() -> u32 {
     CLOCKS.sys.load(Ordering::Relaxed)
 }
 
+/// REF clock frequency.
 pub fn clk_ref_freq() -> u32 {
     CLOCKS.reference.load(Ordering::Relaxed)
 }
 
+/// Peripheral clock frequency.
 pub fn clk_peri_freq() -> u32 {
     CLOCKS.peri.load(Ordering::Relaxed)
 }
 
+/// USB clock frequency.
 pub fn clk_usb_freq() -> u32 {
     CLOCKS.usb.load(Ordering::Relaxed)
 }
 
+/// ADC clock frequency.
 pub fn clk_adc_freq() -> u32 {
     CLOCKS.adc.load(Ordering::Relaxed)
 }
 
+/// RTC clock frequency.
 pub fn clk_rtc_freq() -> u16 {
     CLOCKS.rtc.load(Ordering::Relaxed)
 }
@@ -708,7 +770,9 @@ fn configure_pll(p: pac::pll::Pll, input_freq: u32, config: PllConfig) -> u32 {
     vco_freq / ((config.post_div1 * config.post_div2) as u32)
 }
 
+/// General purpose input clock pin.
 pub trait GpinPin: crate::gpio::Pin {
+    /// Pin number.
     const NR: usize;
 }
 
@@ -723,12 +787,14 @@ macro_rules! impl_gpinpin {
 impl_gpinpin!(PIN_20, 20, 0);
 impl_gpinpin!(PIN_22, 22, 1);
 
+/// General purpose clock input driver.
 pub struct Gpin<'d, T: Pin> {
     gpin: PeripheralRef<'d, AnyPin>,
     _phantom: PhantomData<T>,
 }
 
 impl<'d, T: Pin> Gpin<'d, T> {
+    /// Create new gpin driver.
     pub fn new<P: GpinPin>(gpin: impl Peripheral<P = P> + 'd) -> Gpin<'d, P> {
         into_ref!(gpin);
 
@@ -754,7 +820,9 @@ impl<'d, T: Pin> Drop for Gpin<'d, T> {
     }
 }
 
+/// General purpose clock output pin.
 pub trait GpoutPin: crate::gpio::Pin {
+    /// Pin number.
     fn number(&self) -> usize;
 }
 
@@ -773,26 +841,38 @@ impl_gpoutpin!(PIN_23, 1);
 impl_gpoutpin!(PIN_24, 2);
 impl_gpoutpin!(PIN_25, 3);
 
+/// Gpout clock source.
 #[repr(u8)]
 pub enum GpoutSrc {
+    /// Sys PLL.
     PllSys = ClkGpoutCtrlAuxsrc::CLKSRC_PLL_SYS as _,
     // Gpin0 = ClkGpoutCtrlAuxsrc::CLKSRC_GPIN0 as _ ,
     // Gpin1 = ClkGpoutCtrlAuxsrc::CLKSRC_GPIN1 as _ ,
+    /// USB PLL.
     PllUsb = ClkGpoutCtrlAuxsrc::CLKSRC_PLL_USB as _,
+    /// ROSC.
     Rosc = ClkGpoutCtrlAuxsrc::ROSC_CLKSRC as _,
+    /// XOSC.
     Xosc = ClkGpoutCtrlAuxsrc::XOSC_CLKSRC as _,
+    /// SYS.
     Sys = ClkGpoutCtrlAuxsrc::CLK_SYS as _,
+    /// USB.
     Usb = ClkGpoutCtrlAuxsrc::CLK_USB as _,
+    /// ADC.
     Adc = ClkGpoutCtrlAuxsrc::CLK_ADC as _,
+    /// RTC.
     Rtc = ClkGpoutCtrlAuxsrc::CLK_RTC as _,
+    /// REF.
     Ref = ClkGpoutCtrlAuxsrc::CLK_REF as _,
 }
 
+/// General purpose clock output driver.
 pub struct Gpout<'d, T: GpoutPin> {
     gpout: PeripheralRef<'d, T>,
 }
 
 impl<'d, T: GpoutPin> Gpout<'d, T> {
+    /// Create new general purpose cloud output.
     pub fn new(gpout: impl Peripheral<P = T> + 'd) -> Self {
         into_ref!(gpout);
 
@@ -801,6 +881,7 @@ impl<'d, T: GpoutPin> Gpout<'d, T> {
         Self { gpout }
     }
 
+    /// Set clock divider.
     pub fn set_div(&self, int: u32, frac: u8) {
         let c = pac::CLOCKS;
         c.clk_gpout_div(self.gpout.number()).write(|w| {
@@ -809,6 +890,7 @@ impl<'d, T: GpoutPin> Gpout<'d, T> {
         });
     }
 
+    /// Set clock source.
     pub fn set_src(&self, src: GpoutSrc) {
         let c = pac::CLOCKS;
         c.clk_gpout_ctrl(self.gpout.number()).modify(|w| {
@@ -816,6 +898,7 @@ impl<'d, T: GpoutPin> Gpout<'d, T> {
         });
     }
 
+    /// Enable clock.
     pub fn enable(&self) {
         let c = pac::CLOCKS;
         c.clk_gpout_ctrl(self.gpout.number()).modify(|w| {
@@ -823,6 +906,7 @@ impl<'d, T: GpoutPin> Gpout<'d, T> {
         });
     }
 
+    /// Disable clock.
     pub fn disable(&self) {
         let c = pac::CLOCKS;
         c.clk_gpout_ctrl(self.gpout.number()).modify(|w| {
@@ -830,6 +914,7 @@ impl<'d, T: GpoutPin> Gpout<'d, T> {
         });
     }
 
+    /// Clock frequency.
     pub fn get_freq(&self) -> u32 {
         let c = pac::CLOCKS;
         let src = c.clk_gpout_ctrl(self.gpout.number()).read().auxsrc();

embassy-rp/src/dma.rs

@@ -38,6 +38,9 @@ pub(crate) unsafe fn init() {
     interrupt::DMA_IRQ_0.enable();
 }
 
+/// DMA read.
+///
+/// SAFETY: Slice must point to a valid location reachable by DMA.
 pub unsafe fn read<'a, C: Channel, W: Word>(
     ch: impl Peripheral<P = C> + 'a,
     from: *const W,
@@ -57,6 +60,9 @@ pub unsafe fn read<'a, C: Channel, W: Word>(
     )
 }
 
+/// DMA write.
+///
+/// SAFETY: Slice must point to a valid location reachable by DMA.
 pub unsafe fn write<'a, C: Channel, W: Word>(
     ch: impl Peripheral<P = C> + 'a,
     from: *const [W],
@@ -79,6 +85,9 @@ pub unsafe fn write<'a, C: Channel, W: Word>(
 // static mut so that this is allocated in RAM.
 static mut DUMMY: u32 = 0;
 
+/// DMA repeated write.
+///
+/// SAFETY: Slice must point to a valid location reachable by DMA.
 pub unsafe fn write_repeated<'a, C: Channel, W: Word>(
     ch: impl Peripheral<P = C> + 'a,
     to: *mut W,
@@ -97,6 +106,9 @@ pub unsafe fn write_repeated<'a, C: Channel, W: Word>(
     )
 }
 
+/// DMA copy between slices.
+///
+/// SAFETY: Slices must point to locations reachable by DMA.
 pub unsafe fn copy<'a, C: Channel, W: Word>(
     ch: impl Peripheral<P = C> + 'a,
     from: &[W],
@@ -152,6 +164,7 @@ fn copy_inner<'a, C: Channel>(
     Transfer::new(ch)
 }
 
+/// DMA transfer driver.
 #[must_use = "futures do nothing unless you `.await` or poll them"]
 pub struct Transfer<'a, C: Channel> {
     channel: PeripheralRef<'a, C>,
@@ -201,19 +214,25 @@ mod sealed {
     pub trait Word {}
 }
 
+/// DMA channel interface.
 pub trait Channel: Peripheral<P = Self> + sealed::Channel + Into<AnyChannel> + Sized + 'static {
+    /// Channel number.
     fn number(&self) -> u8;
 
+    /// Channel registry block.
     fn regs(&self) -> pac::dma::Channel {
         pac::DMA.ch(self.number() as _)
     }
 
+    /// Convert into type-erased [AnyChannel].
     fn degrade(self) -> AnyChannel {
         AnyChannel { number: self.number() }
     }
 }
 
+/// DMA word.
 pub trait Word: sealed::Word {
+    /// Word size.
     fn size() -> vals::DataSize;
 }
 
@@ -238,6 +257,7 @@ impl Word for u32 {
     }
 }
 
+/// Type erased DMA channel.
 pub struct AnyChannel {
     number: u8,
 }

embassy-rp/src/flash.rs

@@ -1,3 +1,4 @@
+//! Flash driver.
 use core::future::Future;
 use core::marker::PhantomData;
 use core::pin::Pin;
@@ -13,9 +14,10 @@ use crate::dma::{AnyChannel, Channel, Transfer};
 use crate::pac;
 use crate::peripherals::FLASH;
 
+/// Flash base address.
 pub const FLASH_BASE: *const u32 = 0x10000000 as _;
 
-// If running from RAM, we might have no boot2. Use bootrom `flash_enter_cmd_xip` instead.
+/// If running from RAM, we might have no boot2. Use bootrom `flash_enter_cmd_xip` instead.
 // TODO: when run-from-ram is set, completely skip the "pause cores and jumpp to RAM" dance.
 pub const USE_BOOT2: bool = !cfg!(feature = "run-from-ram");
 
@@ -24,10 +26,15 @@ pub const USE_BOOT2: bool = !cfg!(feature = "run-from-ram");
 // These limitations are currently enforced because of using the
 // RP2040 boot-rom flash functions, that are optimized for flash compatibility
 // rather than performance.
+/// Flash page size.
 pub const PAGE_SIZE: usize = 256;
+/// Flash write size.
 pub const WRITE_SIZE: usize = 1;
+/// Flash read size.
 pub const READ_SIZE: usize = 1;
+/// Flash erase size.
 pub const ERASE_SIZE: usize = 4096;
+/// Flash DMA read size.
 pub const ASYNC_READ_SIZE: usize = 4;
 
 /// Error type for NVMC operations.
@@ -38,7 +45,9 @@ pub enum Error {
     OutOfBounds,
     /// Unaligned operation or using unaligned buffers.
     Unaligned,
+    /// Accessed from the wrong core.
     InvalidCore,
+    /// Other error
     Other,
 }
 
@@ -96,12 +105,18 @@ impl<'a, 'd, T: Instance, const FLASH_SIZE: usize> Drop for BackgroundRead<'a, '
     }
 }
 
+/// Flash driver.
 pub struct Flash<'d, T: Instance, M: Mode, const FLASH_SIZE: usize> {
     dma: Option<PeripheralRef<'d, AnyChannel>>,
     phantom: PhantomData<(&'d mut T, M)>,
 }
 
 impl<'d, T: Instance, M: Mode, const FLASH_SIZE: usize> Flash<'d, T, M, FLASH_SIZE> {
+    /// Blocking read.
+    ///
+    /// The offset and buffer must be aligned.
+    ///
+    /// NOTE: `offset` is an offset from the flash start, NOT an absolute address.
     pub fn blocking_read(&mut self, offset: u32, bytes: &mut [u8]) -> Result<(), Error> {
         trace!(
             "Reading from 0x{:x} to 0x{:x}",
@@ -116,10 +131,14 @@ impl<'d, T: Instance, M: Mode, const FLASH_SIZE: usize> Flash<'d, T, M, FLASH_SI
         Ok(())
     }
 
+    /// Flash capacity.
     pub fn capacity(&self) -> usize {
         FLASH_SIZE
     }
 
+    /// Blocking erase.
+    ///
+    /// NOTE: `offset` is an offset from the flash start, NOT an absolute address.
     pub fn blocking_erase(&mut self, from: u32, to: u32) -> Result<(), Error> {
         check_erase(self, from, to)?;
 
@@ -136,6 +155,11 @@ impl<'d, T: Instance, M: Mode, const FLASH_SIZE: usize> Flash<'d, T, M, FLASH_SI
         Ok(())
     }
 
+    /// Blocking write.
+    ///
+    /// The offset and buffer must be aligned.
+    ///
+    /// NOTE: `offset` is an offset from the flash start, NOT an absolute address.
     pub fn blocking_write(&mut self, offset: u32, bytes: &[u8]) -> Result<(), Error> {
         check_write(self, offset, bytes.len())?;
 
@@ -219,6 +243,7 @@ impl<'d, T: Instance, M: Mode, const FLASH_SIZE: usize> Flash<'d, T, M, FLASH_SI
 }
 
 impl<'d, T: Instance, const FLASH_SIZE: usize> Flash<'d, T, Blocking, FLASH_SIZE> {
+    /// Create a new flash driver in blocking mode.
     pub fn new_blocking(_flash: impl Peripheral<P = T> + 'd) -> Self {
         Self {
             dma: None,
@@ -228,6 +253,7 @@ impl<'d, T: Instance, const FLASH_SIZE: usize> Flash<'d, T, Blocking, FLASH_SIZE
 }
 
 impl<'d, T: Instance, const FLASH_SIZE: usize> Flash<'d, T, Async, FLASH_SIZE> {
+    /// Create a new flash driver in async mode.
     pub fn new(_flash: impl Peripheral<P = T> + 'd, dma: impl Peripheral<P = impl Channel> + 'd) -> Self {
         into_ref!(dma);
         Self {
@@ -236,6 +262,11 @@ impl<'d, T: Instance, const FLASH_SIZE: usize> Flash<'d, T, Async, FLASH_SIZE> {
         }
     }
 
+    /// Start a background read operation.
+    ///
+    /// The offset and buffer must be aligned.
+    ///
+    /// NOTE: `offset` is an offset from the flash start, NOT an absolute address.
     pub fn background_read<'a>(
         &'a mut self,
         offset: u32,
@@ -279,6 +310,11 @@ impl<'d, T: Instance, const FLASH_SIZE: usize> Flash<'d, T, Async, FLASH_SIZE> {
         })
     }
 
+    /// Async read.
+    ///
+    /// The offset and buffer must be aligned.
+    ///
+    /// NOTE: `offset` is an offset from the flash start, NOT an absolute address.
     pub async fn read(&mut self, offset: u32, bytes: &mut [u8]) -> Result<(), Error> {
         use core::mem::MaybeUninit;
 
@@ -874,7 +910,9 @@ mod sealed {
     pub trait Mode {}
 }
 
+/// Flash instance.
 pub trait Instance: sealed::Instance {}
+/// Flash mode.
 pub trait Mode: sealed::Mode {}
 
 impl sealed::Instance for FLASH {}
@@ -887,7 +925,9 @@ macro_rules! impl_mode {
     };
 }
 
+/// Flash blocking mode.
 pub struct Blocking;
+/// Flash async mode.
 pub struct Async;
 
 impl_mode!(Blocking);

embassy-rp/src/gpio.rs

@@ -1,3 +1,4 @@
+//! GPIO driver.
 #![macro_use]
 use core::convert::Infallible;
 use core::future::Future;
@@ -23,7 +24,9 @@ static QSPI_WAKERS: [AtomicWaker; QSPI_PIN_COUNT] = [NEW_AW; QSPI_PIN_COUNT];
 /// Represents a digital input or output level.
 #[derive(Debug, Eq, PartialEq, Clone, Copy)]
 pub enum Level {
+    /// Logical low.
     Low,
+    /// Logical high.
     High,
 }
 
@@ -48,48 +51,66 @@ impl From<Level> for bool {
 /// Represents a pull setting for an input.
 #[derive(Debug, Clone, Copy, Eq, PartialEq)]
 pub enum Pull {
+    /// No pull.
     None,
+    /// Internal pull-up resistor.
     Up,
+    /// Internal pull-down resistor.
     Down,
 }
 
 /// Drive strength of an output
 #[derive(Debug, Eq, PartialEq)]
 pub enum Drive {
+    /// 2 mA drive.
     _2mA,
+    /// 4 mA drive.
     _4mA,
+    /// 8 mA drive.
     _8mA,
+    /// 1 2mA drive.
     _12mA,
 }
 /// Slew rate of an output
 #[derive(Debug, Eq, PartialEq)]
 pub enum SlewRate {
+    /// Fast slew rate.
     Fast,
+    /// Slow slew rate.
     Slow,
 }
 
 /// A GPIO bank with up to 32 pins.
 #[derive(Debug, Eq, PartialEq)]
 pub enum Bank {
+    /// Bank 0.
     Bank0 = 0,
+    /// QSPI.
     #[cfg(feature = "qspi-as-gpio")]
     Qspi = 1,
 }
 
+/// Dormant mode config.
 #[derive(Debug, Eq, PartialEq, Copy, Clone, Default)]
 #[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub struct DormantWakeConfig {
+    /// Wake on edge high.
     pub edge_high: bool,
+    /// Wake on edge low.
     pub edge_low: bool,
+    /// Wake on level high.
     pub level_high: bool,
+    /// Wake on level low.
     pub level_low: bool,
 }
 
+/// GPIO input driver.
 pub struct Input<'d, T: Pin> {
     pin: Flex<'d, T>,
 }
 
 impl<'d, T: Pin> Input<'d, T> {
+    /// Create GPIO input driver for a [Pin] with the provided [Pull] configuration.
     #[inline]
     pub fn new(pin: impl Peripheral<P = T> + 'd, pull: Pull) -> Self {
         let mut pin = Flex::new(pin);
@@ -104,11 +125,13 @@ impl<'d, T: Pin> Input<'d, T> {
         self.pin.set_schmitt(enable)
     }
 
+    /// Get whether the pin input level is high.
     #[inline]
     pub fn is_high(&mut self) -> bool {
         self.pin.is_high()
     }
 
+    /// Get whether the pin input level is low.
     #[inline]
     pub fn is_low(&mut self) -> bool {
         self.pin.is_low()
@@ -120,31 +143,37 @@ impl<'d, T: Pin> Input<'d, T> {
         self.pin.get_level()
     }
 
+    /// Wait until the pin is high. If it is already high, return immediately.
     #[inline]
     pub async fn wait_for_high(&mut self) {
         self.pin.wait_for_high().await;
     }
 
+    /// Wait until the pin is low. If it is already low, return immediately.
     #[inline]
     pub async fn wait_for_low(&mut self) {
         self.pin.wait_for_low().await;
     }
 
+    /// Wait for the pin to undergo a transition from low to high.
     #[inline]
     pub async fn wait_for_rising_edge(&mut self) {
         self.pin.wait_for_rising_edge().await;
     }
 
+    /// Wait for the pin to undergo a transition from high to low.
     #[inline]
     pub async fn wait_for_falling_edge(&mut self) {
         self.pin.wait_for_falling_edge().await;
     }
 
+    /// Wait for the pin to undergo any transition, i.e low to high OR high to low.
     #[inline]
     pub async fn wait_for_any_edge(&mut self) {
         self.pin.wait_for_any_edge().await;
     }
 
+    /// Configure dormant wake.
     #[inline]
     pub fn dormant_wake(&mut self, cfg: DormantWakeConfig) -> DormantWake<T> {
         self.pin.dormant_wake(cfg)
@@ -155,10 +184,15 @@ impl<'d, T: Pin> Input<'d, T> {
 #[derive(Debug, Eq, PartialEq, Copy, Clone)]
 #[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub enum InterruptTrigger {
+    /// Trigger on pin low.
     LevelLow,
+    /// Trigger on pin high.
     LevelHigh,
+    /// Trigger on high to low transition.
     EdgeLow,
+    /// Trigger on low to high transition.
     EdgeHigh,
+    /// Trigger on any transition.
     AnyEdge,
 }
 
@@ -226,6 +260,7 @@ struct InputFuture<'a, T: Pin> {
 }
 
 impl<'d, T: Pin> InputFuture<'d, T> {
+    /// Create a new future wiating for input trigger.
     pub fn new(pin: impl Peripheral<P = T> + 'd, level: InterruptTrigger) -> Self {
         into_ref!(pin);
         let pin_group = (pin.pin() % 8) as usize;
@@ -308,11 +343,13 @@ impl<'d, T: Pin> Future for InputFuture<'d, T> {
     }
 }
 
+/// GPIO output driver.
 pub struct Output<'d, T: Pin> {
     pin: Flex<'d, T>,
 }
 
 impl<'d, T: Pin> Output<'d, T> {
+    /// Create GPIO output driver for a [Pin] with the provided [Level].
     #[inline]
     pub fn new(pin: impl Peripheral<P = T> + 'd, initial_output: Level) -> Self {
         let mut pin = Flex::new(pin);
@@ -331,7 +368,7 @@ impl<'d, T: Pin> Output<'d, T> {
         self.pin.set_drive_strength(strength)
     }
 
-    // Set the pin's slew rate.
+    /// Set the pin's slew rate.
     #[inline]
     pub fn set_slew_rate(&mut self, slew_rate: SlewRate) {
         self.pin.set_slew_rate(slew_rate)
@@ -386,6 +423,7 @@ pub struct OutputOpenDrain<'d, T: Pin> {
 }
 
 impl<'d, T: Pin> OutputOpenDrain<'d, T> {
+    /// Create GPIO output driver for a [Pin] in open drain mode with the provided [Level].
     #[inline]
     pub fn new(pin: impl Peripheral<P = T> + 'd, initial_output: Level) -> Self {
         let mut pin = Flex::new(pin);
@@ -403,7 +441,7 @@ impl<'d, T: Pin> OutputOpenDrain<'d, T> {
         self.pin.set_drive_strength(strength)
     }
 
-    // Set the pin's slew rate.
+    /// Set the pin's slew rate.
     #[inline]
     pub fn set_slew_rate(&mut self, slew_rate: SlewRate) {
         self.pin.set_slew_rate(slew_rate)
@@ -456,11 +494,13 @@ impl<'d, T: Pin> OutputOpenDrain<'d, T> {
         self.pin.toggle_set_as_output()
     }
 
+    /// Get whether the pin input level is high.
     #[inline]
     pub fn is_high(&mut self) -> bool {
         self.pin.is_high()
     }
 
+    /// Get whether the pin input level is low.
     #[inline]
     pub fn is_low(&mut self) -> bool {
         self.pin.is_low()
@@ -472,26 +512,31 @@ impl<'d, T: Pin> OutputOpenDrain<'d, T> {
         self.is_high().into()
     }
 
+    /// Wait until the pin is high. If it is already high, return immediately.
     #[inline]
     pub async fn wait_for_high(&mut self) {
         self.pin.wait_for_high().await;
     }
 
+    /// Wait until the pin is low. If it is already low, return immediately.
     #[inline]
     pub async fn wait_for_low(&mut self) {
         self.pin.wait_for_low().await;
     }
 
+    /// Wait for the pin to undergo a transition from low to high.
     #[inline]
     pub async fn wait_for_rising_edge(&mut self) {
         self.pin.wait_for_rising_edge().await;
     }
 
+    /// Wait for the pin to undergo a transition from high to low.
     #[inline]
     pub async fn wait_for_falling_edge(&mut self) {
         self.pin.wait_for_falling_edge().await;
     }
 
+    /// Wait for the pin to undergo any transition, i.e low to high OR high to low.
     #[inline]
     pub async fn wait_for_any_edge(&mut self) {
         self.pin.wait_for_any_edge().await;
@@ -508,6 +553,10 @@ pub struct Flex<'d, T: Pin> {
 }
 
 impl<'d, T: Pin> Flex<'d, T> {
+    /// Wrap the pin in a `Flex`.
+    ///
+    /// The pin remains disconnected. The initial output level is unspecified, but can be changed
+    /// before the pin is put into output mode.
     #[inline]
     pub fn new(pin: impl Peripheral<P = T> + 'd) -> Self {
         into_ref!(pin);
@@ -556,7 +605,7 @@ impl<'d, T: Pin> Flex<'d, T> {
         });
     }
 
-    // Set the pin's slew rate.
+    /// Set the pin's slew rate.
     #[inline]
     pub fn set_slew_rate(&mut self, slew_rate: SlewRate) {
         self.pin.pad_ctrl().modify(|w| {
@@ -589,6 +638,7 @@ impl<'d, T: Pin> Flex<'d, T> {
         self.pin.sio_oe().value_set().write_value(self.bit())
     }
 
+    /// Set as output pin.
     #[inline]
     pub fn is_set_as_output(&mut self) -> bool {
         self.ref_is_set_as_output()
@@ -599,15 +649,18 @@ impl<'d, T: Pin> Flex<'d, T> {
         (self.pin.sio_oe().value().read() & self.bit()) != 0
     }
 
+    /// Toggle output pin.
     #[inline]
     pub fn toggle_set_as_output(&mut self) {
         self.pin.sio_oe().value_xor().write_value(self.bit())
     }
 
+    /// Get whether the pin input level is high.
     #[inline]
     pub fn is_high(&mut self) -> bool {
         !self.is_low()
     }
+    /// Get whether the pin input level is low.
 
     #[inline]
     pub fn is_low(&mut self) -> bool {
@@ -675,31 +728,37 @@ impl<'d, T: Pin> Flex<'d, T> {
         self.pin.sio_out().value_xor().write_value(self.bit())
     }
 
+    /// Wait until the pin is high. If it is already high, return immediately.
     #[inline]
     pub async fn wait_for_high(&mut self) {
         InputFuture::new(&mut self.pin, InterruptTrigger::LevelHigh).await;
     }
 
+    /// Wait until the pin is low. If it is already low, return immediately.
     #[inline]
     pub async fn wait_for_low(&mut self) {
         InputFuture::new(&mut self.pin, InterruptTrigger::LevelLow).await;
     }
 
+    /// Wait for the pin to undergo a transition from low to high.
     #[inline]
     pub async fn wait_for_rising_edge(&mut self) {
         InputFuture::new(&mut self.pin, InterruptTrigger::EdgeHigh).await;
     }
 
+    /// Wait for the pin to undergo a transition from high to low.
     #[inline]
     pub async fn wait_for_falling_edge(&mut self) {
         InputFuture::new(&mut self.pin, InterruptTrigger::EdgeLow).await;
     }
 
+    /// Wait for the pin to undergo any transition, i.e low to high OR high to low.
     #[inline]
     pub async fn wait_for_any_edge(&mut self) {
         InputFuture::new(&mut self.pin, InterruptTrigger::AnyEdge).await;
     }
 
+    /// Configure dormant wake.
     #[inline]
     pub fn dormant_wake(&mut self, cfg: DormantWakeConfig) -> DormantWake<T> {
         let idx = self.pin._pin() as usize;
@@ -737,6 +796,7 @@ impl<'d, T: Pin> Drop for Flex<'d, T> {
     }
 }
 
+/// Dormant wake driver.
 pub struct DormantWake<'w, T: Pin> {
     pin: PeripheralRef<'w, T>,
     cfg: DormantWakeConfig,
@@ -818,6 +878,7 @@ pub(crate) mod sealed {
     }
 }
 
+/// Interface for a Pin that can be configured by an [Input] or [Output] driver, or converted to an [AnyPin].
 pub trait Pin: Peripheral<P = Self> + Into<AnyPin> + sealed::Pin + Sized + 'static {
     /// Degrade to a generic pin struct
     fn degrade(self) -> AnyPin {
@@ -839,6 +900,7 @@ pub trait Pin: Peripheral<P = Self> + Into<AnyPin> + sealed::Pin + Sized + 'stat
     }
 }
 
+/// Type-erased GPIO pin
 pub struct AnyPin {
     pin_bank: u8,
 }

embassy-rp/src/i2c.rs

@@ -1,3 +1,4 @@
+//! I2C driver.
 use core::future;
 use core::marker::PhantomData;
 use core::task::Poll;
@@ -22,6 +23,7 @@ pub enum AbortReason {
     ArbitrationLoss,
     /// Transmit ended with data still in fifo
     TxNotEmpty(u16),
+    /// Other reason.
     Other(u32),
 }
 
@@ -41,9 +43,11 @@ pub enum Error {
     AddressReserved(u16),
 }
 
+/// I2C config.
 #[non_exhaustive]
 #[derive(Copy, Clone)]
 pub struct Config {
+    /// Frequency.
     pub frequency: u32,
 }
 
@@ -53,13 +57,16 @@ impl Default for Config {
     }
 }
 
+/// Size of I2C FIFO.
 pub const FIFO_SIZE: u8 = 16;
 
+/// I2C driver.
 pub struct I2c<'d, T: Instance, M: Mode> {
     phantom: PhantomData<(&'d mut T, M)>,
 }
 
 impl<'d, T: Instance> I2c<'d, T, Blocking> {
+    /// Create a new driver instance in blocking mode.
     pub fn new_blocking(
         peri: impl Peripheral<P = T> + 'd,
         scl: impl Peripheral<P = impl SclPin<T>> + 'd,
@@ -72,6 +79,7 @@ impl<'d, T: Instance> I2c<'d, T, Blocking> {
 }
 
 impl<'d, T: Instance> I2c<'d, T, Async> {
+    /// Create a new driver instance in async mode.
     pub fn new_async(
         peri: impl Peripheral<P = T> + 'd,
         scl: impl Peripheral<P = impl SclPin<T>> + 'd,
@@ -292,16 +300,19 @@ impl<'d, T: Instance> I2c<'d, T, Async> {
         }
     }
 
+    /// Read from address into buffer using DMA.
     pub async fn read_async(&mut self, addr: u16, buffer: &mut [u8]) -> Result<(), Error> {
         Self::setup(addr)?;
         self.read_async_internal(buffer, true, true).await
     }
 
+    /// Write to address from buffer using DMA.
     pub async fn write_async(&mut self, addr: u16, bytes: impl IntoIterator<Item = u8>) -> Result<(), Error> {
         Self::setup(addr)?;
         self.write_async_internal(bytes, true).await
     }
 
+    /// Write to address from bytes and read from address into buffer using DMA.
     pub async fn write_read_async(
         &mut self,
         addr: u16,
@@ -314,6 +325,7 @@ impl<'d, T: Instance> I2c<'d, T, Async> {
     }
 }
 
+/// Interrupt handler.
 pub struct InterruptHandler<T: Instance> {
     _uart: PhantomData<T>,
 }
@@ -569,17 +581,20 @@ impl<'d, T: Instance + 'd, M: Mode> I2c<'d, T, M> {
     // Blocking public API
     // =========================
 
+    /// Read from address into buffer blocking caller until done.
     pub fn blocking_read(&mut self, address: u8, read: &mut [u8]) -> Result<(), Error> {
         Self::setup(address.into())?;
         self.read_blocking_internal(read, true, true)
         // Automatic Stop
     }
 
+    /// Write to address from buffer blocking caller until done.
     pub fn blocking_write(&mut self, address: u8, write: &[u8]) -> Result<(), Error> {
         Self::setup(address.into())?;
         self.write_blocking_internal(write, true)
     }
 
+    /// Write to address from bytes and read from address into buffer blocking caller until done.
     pub fn blocking_write_read(&mut self, address: u8, write: &[u8], read: &mut [u8]) -> Result<(), Error> {
         Self::setup(address.into())?;
         self.write_blocking_internal(write, false)?;
@@ -742,6 +757,7 @@ where
     }
 }
 
+/// Check if address is reserved.
 pub fn i2c_reserved_addr(addr: u16) -> bool {
     ((addr & 0x78) == 0 || (addr & 0x78) == 0x78) && addr != 0
 }
@@ -768,6 +784,7 @@ mod sealed {
     pub trait SclPin<T: Instance> {}
 }
 
+/// Driver mode.
 pub trait Mode: sealed::Mode {}
 
 macro_rules! impl_mode {
@@ -777,12 +794,15 @@ macro_rules! impl_mode {
     };
 }
 
+/// Blocking mode.
 pub struct Blocking;
+/// Async mode.
 pub struct Async;
 
 impl_mode!(Blocking);
 impl_mode!(Async);
 
+/// I2C instance.
 pub trait Instance: sealed::Instance {}
 
 macro_rules! impl_instance {
@@ -819,7 +839,9 @@ macro_rules! impl_instance {
 impl_instance!(I2C0, I2C0_IRQ, set_i2c0, 32, 33);
 impl_instance!(I2C1, I2C1_IRQ, set_i2c1, 34, 35);
 
+/// SDA pin.
 pub trait SdaPin<T: Instance>: sealed::SdaPin<T> + crate::gpio::Pin {}
+/// SCL pin.
 pub trait SclPin<T: Instance>: sealed::SclPin<T> + crate::gpio::Pin {}
 
 macro_rules! impl_pin {

embassy-rp/src/i2c_slave.rs

@@ -1,3 +1,4 @@
+//! I2C slave driver.
 use core::future;
 use core::marker::PhantomData;
 use core::task::Poll;
@@ -63,11 +64,13 @@ impl Default for Config {
     }
 }
 
+/// I2CSlave driver.
 pub struct I2cSlave<'d, T: Instance> {
     phantom: PhantomData<&'d mut T>,
 }
 
 impl<'d, T: Instance> I2cSlave<'d, T> {
+    /// Create a new instance.
     pub fn new(
         _peri: impl Peripheral<P = T> + 'd,
         scl: impl Peripheral<P = impl SclPin<T>> + 'd,

embassy-rp/src/lib.rs

@@ -1,6 +1,7 @@
 #![no_std]
 #![allow(async_fn_in_trait)]
 #![doc = include_str!("../README.md")]
+#![warn(missing_docs)]
 
 // This mod MUST go first, so that the others see its macros.
 pub(crate) mod fmt;

embassy-rp/src/pio/mod.rs

@@ -1,3 +1,4 @@
+//! PIO driver.
 use core::future::Future;
 use core::marker::PhantomData;
 use core::pin::Pin as FuturePin;

embassy-rp/src/pwm.rs

@@ -119,11 +119,13 @@ impl<'d, T: Channel> Pwm<'d, T> {
         }
     }
 
+    /// Create PWM driver without any configured pins.
     #[inline]
     pub fn new_free(inner: impl Peripheral<P = T> + 'd, config: Config) -> Self {
         Self::new_inner(inner, None, None, config, Divmode::DIV)
     }
 
+    /// Create PWM driver with a single 'a' as output.
     #[inline]
     pub fn new_output_a(
         inner: impl Peripheral<P = T> + 'd,
@@ -134,6 +136,7 @@ impl<'d, T: Channel> Pwm<'d, T> {
         Self::new_inner(inner, Some(a.map_into()), None, config, Divmode::DIV)
     }
 
+    /// Create PWM driver with a single 'b' pin as output.
     #[inline]
     pub fn new_output_b(
         inner: impl Peripheral<P = T> + 'd,
@@ -144,6 +147,7 @@ impl<'d, T: Channel> Pwm<'d, T> {
         Self::new_inner(inner, None, Some(b.map_into()), config, Divmode::DIV)
     }
 
+    /// Create PWM driver with a 'a' and 'b' pins as output.
     #[inline]
     pub fn new_output_ab(
         inner: impl Peripheral<P = T> + 'd,
@@ -155,6 +159,7 @@ impl<'d, T: Channel> Pwm<'d, T> {
         Self::new_inner(inner, Some(a.map_into()), Some(b.map_into()), config, Divmode::DIV)
     }
 
+    /// Create PWM driver with a single 'b' as input pin.
     #[inline]
     pub fn new_input(
         inner: impl Peripheral<P = T> + 'd,
@@ -166,6 +171,7 @@ impl<'d, T: Channel> Pwm<'d, T> {
         Self::new_inner(inner, None, Some(b.map_into()), config, mode.into())
     }
 
+    /// Create PWM driver with a 'a' and 'b' pins in the desired input mode.
     #[inline]
     pub fn new_output_input(
         inner: impl Peripheral<P = T> + 'd,
@@ -178,6 +184,7 @@ impl<'d, T: Channel> Pwm<'d, T> {
         Self::new_inner(inner, Some(a.map_into()), Some(b.map_into()), config, mode.into())
     }
 
+    /// Set the PWM config.
     pub fn set_config(&mut self, config: &Config) {
         Self::configure(self.inner.regs(), config);
     }
@@ -221,28 +228,33 @@ impl<'d, T: Channel> Pwm<'d, T> {
         while p.csr().read().ph_ret() {}
     }
 
+    /// Read PWM counter.
     #[inline]
     pub fn counter(&self) -> u16 {
         self.inner.regs().ctr().read().ctr()
     }
 
+    /// Write PWM counter.
     #[inline]
     pub fn set_counter(&self, ctr: u16) {
         self.inner.regs().ctr().write(|w| w.set_ctr(ctr))
     }
 
+    /// Wait for channel interrupt.
     #[inline]
     pub fn wait_for_wrap(&mut self) {
         while !self.wrapped() {}
         self.clear_wrapped();
     }
 
+    /// Check if interrupt for channel is set.
     #[inline]
     pub fn wrapped(&mut self) -> bool {
         pac::PWM.intr().read().0 & self.bit() != 0
     }
 
     #[inline]
+    /// Clear interrupt flag.
     pub fn clear_wrapped(&mut self) {
         pac::PWM.intr().write_value(Intr(self.bit() as _));
     }
@@ -253,15 +265,18 @@ impl<'d, T: Channel> Pwm<'d, T> {
     }
 }
 
+/// Batch representation of PWM channels.
 pub struct PwmBatch(u32);
 
 impl PwmBatch {
     #[inline]
+    /// Enable a PWM channel in this batch.
     pub fn enable(&mut self, pwm: &Pwm<'_, impl Channel>) {
         self.0 |= pwm.bit();
     }
 
     #[inline]
+    /// Enable channels in this batch in a PWM.
     pub fn set_enabled(enabled: bool, batch: impl FnOnce(&mut PwmBatch)) {
         let mut en = PwmBatch(0);
         batch(&mut en);
@@ -289,9 +304,12 @@ mod sealed {
     pub trait Channel {}
 }
 
+/// PWM Channel.
 pub trait Channel: Peripheral<P = Self> + sealed::Channel + Sized + 'static {
+    /// Channel number.
     fn number(&self) -> u8;
 
+    /// Channel register block.
     fn regs(&self) -> pac::pwm::Channel {
         pac::PWM.ch(self.number() as _)
     }
@@ -317,7 +335,9 @@ channel!(PWM_CH5, 5);
 channel!(PWM_CH6, 6);
 channel!(PWM_CH7, 7);
 
+/// PWM Pin A.
 pub trait PwmPinA<T: Channel>: GpioPin {}
+/// PWM Pin B.
 pub trait PwmPinB<T: Channel>: GpioPin {}
 
 macro_rules! impl_pin {

embassy-rp/src/rtc/mod.rs

@@ -1,3 +1,4 @@
+//! RTC driver.
 mod filter;
 
 use embassy_hal_internal::{into_ref, Peripheral, PeripheralRef};

embassy-rp/src/timer.rs

@@ -1,3 +1,4 @@
+//! Timer driver.
 use core::cell::Cell;
 
 use atomic_polyfill::{AtomicU8, Ordering};

embassy-rp/src/uart/buffered.rs

@@ -1,3 +1,4 @@
+//! Buffered UART driver.
 use core::future::{poll_fn, Future};
 use core::slice;
 use core::task::Poll;

embassy-rp/src/uart/mod.rs

@@ -1,3 +1,4 @@
+//! UART driver.
 use core::future::poll_fn;
 use core::marker::PhantomData;
 use core::task::Poll;
@@ -947,7 +948,7 @@ pub struct Async;
 impl_mode!(Blocking);
 impl_mode!(Async);
 
-/// UART instance trait.
+/// UART instance.
 pub trait Instance: sealed::Instance {}
 
 macro_rules! impl_instance {

embassy-rp/src/usb.rs

@@ -1,3 +1,4 @@
+//! USB driver.
 use core::future::poll_fn;
 use core::marker::PhantomData;
 use core::slice;

embassy-stm32/src/i2c/mod.rs

@@ -148,31 +148,20 @@ struct Timeout {
 
 #[allow(dead_code)]
 impl Timeout {
-    #[cfg(not(feature = "time"))]
     #[inline]
     fn check(self) -> Result<(), Error> {
-        Ok(())
-    }
-
         #[cfg(feature = "time")]
-    #[inline]
-    fn check(self) -> Result<(), Error> {
         if Instant::now() > self.deadline {
-            Err(Error::Timeout)
+            return Err(Error::Timeout);
-        } else {
+        }
+
         Ok(())
     }
-    }
 
-    #[cfg(not(feature = "time"))]
     #[inline]
     fn with<R>(self, fut: impl Future<Output = Result<R, Error>>) -> impl Future<Output = Result<R, Error>> {
-        fut
-    }
-
         #[cfg(feature = "time")]
-    #[inline]
+        {
-    fn with<R>(self, fut: impl Future<Output = Result<R, Error>>) -> impl Future<Output = Result<R, Error>> {
             use futures::FutureExt;
 
             embassy_futures::select::select(embassy_time::Timer::at(self.deadline), fut).map(|r| match r {
@@ -180,6 +169,10 @@ impl Timeout {
                 embassy_futures::select::Either::Second(r) => r,
             })
         }
+
+        #[cfg(not(feature = "time"))]
+        fut
+    }
 }
 
 pub(crate) mod sealed {