From a7429a7f468faef9c7a213f800604086af349fe3 Mon Sep 17 00:00:00 2001
From: Ulf Lilleengen <ulf.lilleengen@gmail.com>
Date: Tue, 19 Dec 2023 11:26:08 +0100
Subject: [PATCH] docs: document spi, rtc and rest of uart for embassy-rp

---
 embassy-rp/src/pwm.rs      |  5 ++++
 embassy-rp/src/rtc/mod.rs  |  1 +
 embassy-rp/src/spi.rs      | 31 ++++++++++++++++++++++++
 embassy-rp/src/uart/mod.rs | 48 ++++++++++++++++++++++++++++++++++++--
 4 files changed, 83 insertions(+), 2 deletions(-)

diff --git a/embassy-rp/src/pwm.rs b/embassy-rp/src/pwm.rs
index 516b8254..5b96557a 100644
--- a/embassy-rp/src/pwm.rs
+++ b/embassy-rp/src/pwm.rs
@@ -61,9 +61,13 @@ impl Default for Config {
     }
 }
 
+/// PWM input mode.
 pub enum InputMode {
+    /// Level mode.
     Level,
+    /// Rising edge mode.
     RisingEdge,
+    /// Falling edge mode.
     FallingEdge,
 }
 
@@ -77,6 +81,7 @@ impl From<InputMode> for Divmode {
     }
 }
 
+/// PWM driver.
 pub struct Pwm<'d, T: Channel> {
     inner: PeripheralRef<'d, T>,
     pin_a: Option<PeripheralRef<'d, AnyPin>>,
diff --git a/embassy-rp/src/rtc/mod.rs b/embassy-rp/src/rtc/mod.rs
index 60ca8627..c3df3ee5 100644
--- a/embassy-rp/src/rtc/mod.rs
+++ b/embassy-rp/src/rtc/mod.rs
@@ -194,6 +194,7 @@ mod sealed {
     }
 }
 
+/// RTC peripheral instance.
 pub trait Instance: sealed::Instance {}
 
 impl sealed::Instance for crate::peripherals::RTC {
diff --git a/embassy-rp/src/spi.rs b/embassy-rp/src/spi.rs
index 6ba985a6..a2a22ffe 100644
--- a/embassy-rp/src/spi.rs
+++ b/embassy-rp/src/spi.rs
@@ -11,6 +11,7 @@ use crate::gpio::sealed::Pin as _;
 use crate::gpio::{AnyPin, Pin as GpioPin};
 use crate::{pac, peripherals, Peripheral};
 
+/// SPI errors.
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 #[cfg_attr(feature = "defmt", derive(defmt::Format))]
 #[non_exhaustive]
@@ -18,11 +19,15 @@ pub enum Error {
     // No errors for now
 }
 
+/// SPI configuration.
 #[non_exhaustive]
 #[derive(Clone)]
 pub struct Config {
+    /// Frequency.
     pub frequency: u32,
+    /// Phase.
     pub phase: Phase,
+    /// Polarity.
     pub polarity: Polarity,
 }
 
@@ -36,6 +41,7 @@ impl Default for Config {
     }
 }
 
+/// SPI driver.
 pub struct Spi<'d, T: Instance, M: Mode> {
     inner: PeripheralRef<'d, T>,
     tx_dma: Option<PeripheralRef<'d, AnyChannel>>,
@@ -119,6 +125,7 @@ impl<'d, T: Instance, M: Mode> Spi<'d, T, M> {
         }
     }
 
+    /// Write data to SPI blocking execution until done.
     pub fn blocking_write(&mut self, data: &[u8]) -> Result<(), Error> {
         let p = self.inner.regs();
         for &b in data {
@@ -131,6 +138,7 @@ impl<'d, T: Instance, M: Mode> Spi<'d, T, M> {
         Ok(())
     }
 
+    /// Transfer data in place to SPI blocking execution until done.
     pub fn blocking_transfer_in_place(&mut self, data: &mut [u8]) -> Result<(), Error> {
         let p = self.inner.regs();
         for b in data {
@@ -143,6 +151,7 @@ impl<'d, T: Instance, M: Mode> Spi<'d, T, M> {
         Ok(())
     }
 
+    /// Read data from SPI blocking execution until done.
     pub fn blocking_read(&mut self, data: &mut [u8]) -> Result<(), Error> {
         let p = self.inner.regs();
         for b in data {
@@ -155,6 +164,7 @@ impl<'d, T: Instance, M: Mode> Spi<'d, T, M> {
         Ok(())
     }
 
+    /// Transfer data to SPI blocking execution until done.
     pub fn blocking_transfer(&mut self, read: &mut [u8], write: &[u8]) -> Result<(), Error> {
         let p = self.inner.regs();
         let len = read.len().max(write.len());
@@ -172,12 +182,14 @@ impl<'d, T: Instance, M: Mode> Spi<'d, T, M> {
         Ok(())
     }
 
+    /// Block execution until SPI is done.
     pub fn flush(&mut self) -> Result<(), Error> {
         let p = self.inner.regs();
         while p.sr().read().bsy() {}
         Ok(())
     }
 
+    /// Set SPI frequency.
     pub fn set_frequency(&mut self, freq: u32) {
         let (presc, postdiv) = calc_prescs(freq);
         let p = self.inner.regs();
@@ -196,6 +208,7 @@ impl<'d, T: Instance, M: Mode> Spi<'d, T, M> {
 }
 
 impl<'d, T: Instance> Spi<'d, T, Blocking> {
+    /// Create an SPI driver in blocking mode.
     pub fn new_blocking(
         inner: impl Peripheral<P = T> + 'd,
         clk: impl Peripheral<P = impl ClkPin<T> + 'd> + 'd,
@@ -216,6 +229,7 @@ impl<'d, T: Instance> Spi<'d, T, Blocking> {
         )
     }
 
+    /// Create an SPI driver in blocking mode supporting writes only.
     pub fn new_blocking_txonly(
         inner: impl Peripheral<P = T> + 'd,
         clk: impl Peripheral<P = impl ClkPin<T> + 'd> + 'd,
@@ -235,6 +249,7 @@ impl<'d, T: Instance> Spi<'d, T, Blocking> {
         )
     }
 
+    /// Create an SPI driver in blocking mode supporting reads only.
     pub fn new_blocking_rxonly(
         inner: impl Peripheral<P = T> + 'd,
         clk: impl Peripheral<P = impl ClkPin<T> + 'd> + 'd,
@@ -256,6 +271,7 @@ impl<'d, T: Instance> Spi<'d, T, Blocking> {
 }
 
 impl<'d, T: Instance> Spi<'d, T, Async> {
+    /// Create an SPI driver in async mode supporting DMA operations.
     pub fn new(
         inner: impl Peripheral<P = T> + 'd,
         clk: impl Peripheral<P = impl ClkPin<T> + 'd> + 'd,
@@ -278,6 +294,7 @@ impl<'d, T: Instance> Spi<'d, T, Async> {
         )
     }
 
+    /// Create an SPI driver in async mode supporting DMA write operations only.
     pub fn new_txonly(
         inner: impl Peripheral<P = T> + 'd,
         clk: impl Peripheral<P = impl ClkPin<T> + 'd> + 'd,
@@ -298,6 +315,7 @@ impl<'d, T: Instance> Spi<'d, T, Async> {
         )
     }
 
+    /// Create an SPI driver in async mode supporting DMA read operations only.
     pub fn new_rxonly(
         inner: impl Peripheral<P = T> + 'd,
         clk: impl Peripheral<P = impl ClkPin<T> + 'd> + 'd,
@@ -318,6 +336,7 @@ impl<'d, T: Instance> Spi<'d, T, Async> {
         )
     }
 
+    /// Write data to SPI using DMA.
     pub async fn write(&mut self, buffer: &[u8]) -> Result<(), Error> {
         let tx_ch = self.tx_dma.as_mut().unwrap();
         let tx_transfer = unsafe {
@@ -340,6 +359,7 @@ impl<'d, T: Instance> Spi<'d, T, Async> {
         Ok(())
     }
 
+    /// Read data from SPI using DMA.
     pub async fn read(&mut self, buffer: &mut [u8]) -> Result<(), Error> {
         // Start RX first. Transfer starts when TX starts, if RX
         // is not started yet we might lose bytes.
@@ -365,10 +385,12 @@ impl<'d, T: Instance> Spi<'d, T, Async> {
         Ok(())
     }
 
+    /// Transfer data to SPI using DMA.
     pub async fn transfer(&mut self, rx_buffer: &mut [u8], tx_buffer: &[u8]) -> Result<(), Error> {
         self.transfer_inner(rx_buffer, tx_buffer).await
     }
 
+    /// Transfer data in place to SPI using DMA.
     pub async fn transfer_in_place(&mut self, words: &mut [u8]) -> Result<(), Error> {
         self.transfer_inner(words, words).await
     }
@@ -434,7 +456,10 @@ mod sealed {
     }
 }
 
+/// Mode.
 pub trait Mode: sealed::Mode {}
+
+/// SPI instance trait.
 pub trait Instance: sealed::Instance {}
 
 macro_rules! impl_instance {
@@ -454,9 +479,13 @@ macro_rules! impl_instance {
 impl_instance!(SPI0, Spi0, 16, 17);
 impl_instance!(SPI1, Spi1, 18, 19);
 
+/// CLK pin.
 pub trait ClkPin<T: Instance>: GpioPin {}
+/// CS pin.
 pub trait CsPin<T: Instance>: GpioPin {}
+/// MOSI pin.
 pub trait MosiPin<T: Instance>: GpioPin {}
+/// MISO pin.
 pub trait MisoPin<T: Instance>: GpioPin {}
 
 macro_rules! impl_pin {
@@ -503,7 +532,9 @@ macro_rules! impl_mode {
     };
 }
 
+/// Blocking mode.
 pub struct Blocking;
+/// Async mode.
 pub struct Async;
 
 impl_mode!(Blocking);
diff --git a/embassy-rp/src/uart/mod.rs b/embassy-rp/src/uart/mod.rs
index 26f21193..32be7661 100644
--- a/embassy-rp/src/uart/mod.rs
+++ b/embassy-rp/src/uart/mod.rs
@@ -20,11 +20,16 @@ use crate::{interrupt, pac, peripherals, Peripheral, RegExt};
 mod buffered;
 pub use buffered::{BufferedInterruptHandler, BufferedUart, BufferedUartRx, BufferedUartTx};
 
+/// Word length.
 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
 pub enum DataBits {
+    /// 5 bits.
     DataBits5,
+    /// 6 bits.
     DataBits6,
+    /// 7 bits.
     DataBits7,
+    /// 8 bits.
     DataBits8,
 }
 
@@ -39,13 +44,18 @@ impl DataBits {
     }
 }
 
+/// Parity bit.
 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
 pub enum Parity {
+    /// No parity.
     ParityNone,
+    /// Even parity.
     ParityEven,
+    /// Odd parity.
     ParityOdd,
 }
 
+/// Stop bits.
 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
 pub enum StopBits {
     #[doc = "1 stop bit"]
@@ -54,20 +64,25 @@ pub enum StopBits {
     STOP2,
 }
 
+/// UART config.
 #[non_exhaustive]
 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
 pub struct Config {
+    /// Baud rate.
     pub baudrate: u32,
+    /// Word length.
     pub data_bits: DataBits,
+    /// Stop bits.
     pub stop_bits: StopBits,
+    /// Parity bit.
     pub parity: Parity,
     /// Invert the tx pin output
     pub invert_tx: bool,
     /// Invert the rx pin input
     pub invert_rx: bool,
-    // Invert the rts pin
+    /// Invert the rts pin
     pub invert_rts: bool,
-    // Invert the cts pin
+    /// Invert the cts pin
     pub invert_cts: bool,
 }
 
@@ -102,21 +117,25 @@ pub enum Error {
     Framing,
 }
 
+/// Internal DMA state of UART RX.
 pub struct DmaState {
     rx_err_waker: AtomicWaker,
     rx_errs: AtomicU16,
 }
 
+/// UART driver.
 pub struct Uart<'d, T: Instance, M: Mode> {
     tx: UartTx<'d, T, M>,
     rx: UartRx<'d, T, M>,
 }
 
+/// UART TX driver.
 pub struct UartTx<'d, T: Instance, M: Mode> {
     tx_dma: Option<PeripheralRef<'d, AnyChannel>>,
     phantom: PhantomData<(&'d mut T, M)>,
 }
 
+/// UART RX driver.
 pub struct UartRx<'d, T: Instance, M: Mode> {
     rx_dma: Option<PeripheralRef<'d, AnyChannel>>,
     phantom: PhantomData<(&'d mut T, M)>,
@@ -142,6 +161,7 @@ impl<'d, T: Instance, M: Mode> UartTx<'d, T, M> {
         }
     }
 
+    /// Transmit the provided buffer blocking execution until done.
     pub fn blocking_write(&mut self, buffer: &[u8]) -> Result<(), Error> {
         let r = T::regs();
         for &b in buffer {
@@ -151,12 +171,14 @@ impl<'d, T: Instance, M: Mode> UartTx<'d, T, M> {
         Ok(())
     }
 
+    /// Flush UART TX blocking execution until done.
     pub fn blocking_flush(&mut self) -> Result<(), Error> {
         let r = T::regs();
         while !r.uartfr().read().txfe() {}
         Ok(())
     }
 
+    /// Check if UART is busy transmitting.
     pub fn busy(&self) -> bool {
         T::regs().uartfr().read().busy()
     }
@@ -191,6 +213,8 @@ impl<'d, T: Instance, M: Mode> UartTx<'d, T, M> {
 }
 
 impl<'d, T: Instance> UartTx<'d, T, Blocking> {
+    /// Convert this uart TX instance into a buffered uart using the provided
+    /// irq and transmit buffer.
     pub fn into_buffered(
         self,
         irq: impl Binding<T::Interrupt, BufferedInterruptHandler<T>>,
@@ -203,6 +227,7 @@ impl<'d, T: Instance> UartTx<'d, T, Blocking> {
 }
 
 impl<'d, T: Instance> UartTx<'d, T, Async> {
+    /// Write to UART TX from the provided buffer using DMA.
     pub async fn write(&mut self, buffer: &[u8]) -> Result<(), Error> {
         let ch = self.tx_dma.as_mut().unwrap();
         let transfer = unsafe {
@@ -246,6 +271,7 @@ impl<'d, T: Instance, M: Mode> UartRx<'d, T, M> {
         }
     }
 
+    /// Read from UART RX blocking execution until done.
     pub fn blocking_read(&mut self, mut buffer: &mut [u8]) -> Result<(), Error> {
         while buffer.len() > 0 {
             let received = self.drain_fifo(buffer)?;
@@ -294,6 +320,7 @@ impl<'d, T: Instance, M: Mode> Drop for UartRx<'d, T, M> {
 }
 
 impl<'d, T: Instance> UartRx<'d, T, Blocking> {
+    /// Create a new UART RX instance for blocking mode operations.
     pub fn new_blocking(
         _uart: impl Peripheral<P = T> + 'd,
         rx: impl Peripheral<P = impl RxPin<T>> + 'd,
@@ -304,6 +331,8 @@ impl<'d, T: Instance> UartRx<'d, T, Blocking> {
         Self::new_inner(false, None)
     }
 
+    /// Convert this uart RX instance into a buffered uart using the provided
+    /// irq and receive buffer.
     pub fn into_buffered(
         self,
         irq: impl Binding<T::Interrupt, BufferedInterruptHandler<T>>,
@@ -315,6 +344,7 @@ impl<'d, T: Instance> UartRx<'d, T, Blocking> {
     }
 }
 
+/// Interrupt handler.
 pub struct InterruptHandler<T: Instance> {
     _uart: PhantomData<T>,
 }
@@ -338,6 +368,7 @@ impl<T: Instance> interrupt::typelevel::Handler<T::Interrupt> for InterruptHandl
 }
 
 impl<'d, T: Instance> UartRx<'d, T, Async> {
+    /// Read from UART RX into the provided buffer.
     pub async fn read(&mut self, buffer: &mut [u8]) -> Result<(), Error> {
         // clear error flags before we drain the fifo. errors that have accumulated
         // in the flags will also be present in the fifo.
@@ -458,6 +489,8 @@ impl<'d, T: Instance> Uart<'d, T, Blocking> {
         )
     }
 
+    /// Convert this uart instance into a buffered uart using the provided
+    /// irq, transmit and receive buffers.
     pub fn into_buffered(
         self,
         irq: impl Binding<T::Interrupt, BufferedInterruptHandler<T>>,
@@ -667,22 +700,27 @@ impl<'d, T: Instance + 'd, M: Mode> Uart<'d, T, M> {
 }
 
 impl<'d, T: Instance, M: Mode> Uart<'d, T, M> {
+    /// Transmit the provided buffer blocking execution until done.
     pub fn blocking_write(&mut self, buffer: &[u8]) -> Result<(), Error> {
         self.tx.blocking_write(buffer)
     }
 
+    /// Flush UART TX blocking execution until done.
     pub fn blocking_flush(&mut self) -> Result<(), Error> {
         self.tx.blocking_flush()
     }
 
+    /// Read from UART RX blocking execution until done.
     pub fn blocking_read(&mut self, buffer: &mut [u8]) -> Result<(), Error> {
         self.rx.blocking_read(buffer)
     }
 
+    /// Check if UART is busy transmitting.
     pub fn busy(&self) -> bool {
         self.tx.busy()
     }
 
+    /// Wait until TX is empty and send break condition.
     pub async fn send_break(&mut self, bits: u32) {
         self.tx.send_break(bits).await
     }
@@ -695,10 +733,12 @@ impl<'d, T: Instance, M: Mode> Uart<'d, T, M> {
 }
 
 impl<'d, T: Instance> Uart<'d, T, Async> {
+    /// Write to UART TX from the provided buffer.
     pub async fn write(&mut self, buffer: &[u8]) -> Result<(), Error> {
         self.tx.write(buffer).await
     }
 
+    /// Read from UART RX into the provided buffer.
     pub async fn read(&mut self, buffer: &mut [u8]) -> Result<(), Error> {
         self.rx.read(buffer).await
     }
@@ -889,6 +929,7 @@ mod sealed {
     pub trait RtsPin<T: Instance> {}
 }
 
+/// UART mode.
 pub trait Mode: sealed::Mode {}
 
 macro_rules! impl_mode {
@@ -898,12 +939,15 @@ macro_rules! impl_mode {
     };
 }
 
+/// Blocking mode.
 pub struct Blocking;
+/// Async mode.
 pub struct Async;
 
 impl_mode!(Blocking);
 impl_mode!(Async);
 
+/// UART instance trait.
 pub trait Instance: sealed::Instance {}
 
 macro_rules! impl_instance {