embassy-rp: Add basic ADC module

3 files changed, 214 insertions, 0 deletions

diff --git a/embassy-rp/src/adc.rs b/embassy-rp/src/adc.rs
new file mode 100644
index 000000000..acef4deaf
--- /dev/null
+++ b/embassy-rp/src/adc.rs
@@ -0,0 +1,178 @@
+use core::future::poll_fn;
+use core::marker::PhantomData;
+use core::sync::atomic::{compiler_fence, Ordering};
+use core::task::Poll;
+
+use embassy_hal_common::into_ref;
+use embassy_sync::waitqueue::AtomicWaker;
+use embedded_hal_02::adc::{Channel, OneShot};
+
+use crate::interrupt::{self, InterruptExt};
+use crate::peripherals::ADC;
+use crate::{pac, peripherals, Peripheral};
+static WAKER: AtomicWaker = AtomicWaker::new();
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+#[non_exhaustive]
+pub enum Error {
+    // No errors for now
+}
+
+#[non_exhaustive]
+pub struct Config {}
+
+impl Default for Config {
+    fn default() -> Self {
+        Self {}
+    }
+}
+pub struct Adc<'d> {
+    phantom: PhantomData<&'d ADC>,
+}
+
+impl<'d> Adc<'d> {
+    #[inline]
+    fn regs() -> pac::adc::Adc {
+        pac::ADC
+    }
+
+    #[inline]
+    fn reset() -> pac::resets::regs::Peripherals {
+        let mut ret = pac::resets::regs::Peripherals::default();
+        ret.set_adc(true);
+        ret
+    }
+
+    pub fn new(
+        _inner: impl Peripheral<P = ADC> + 'd,
+        irq: impl Peripheral<P = interrupt::ADC_IRQ_FIFO> + 'd,
+        _config: Config,
+    ) -> Self {
+        into_ref!(irq);
+        unsafe {
+            let reset = Self::reset();
+            crate::reset::reset(reset);
+            crate::reset::unreset_wait(reset);
+            let r = Self::regs();
+            // Enable ADC
+            r.cs().write(|w| w.set_en(true));
+            // Wait for ADC ready
+            while !r.cs().read().ready() {}
+        }
+
+        // Setup IRQ
+        irq.disable();
+        irq.set_handler(|_| unsafe {
+            let r = Self::regs();
+            r.inte().modify(|w| w.set_fifo(false));
+            WAKER.wake();
+        });
+        irq.unpend();
+        irq.enable();
+
+        Self { phantom: PhantomData }
+    }
+
+    async fn wait_for_ready() {
+        let r = Self::regs();
+        unsafe {
+            r.inte().modify(|w| w.set_fifo(true));
+            compiler_fence(Ordering::SeqCst);
+            poll_fn(|cx| {
+                WAKER.register(cx.waker());
+                if r.cs().read().ready() {
+                    return Poll::Ready(());
+                }
+                Poll::Pending
+            })
+            .await;
+        }
+    }
+
+    pub async fn read<PIN: Channel<Adc<'d>, ID = u8>>(&mut self, _pin: &mut PIN) -> u16 {
+        let r = Self::regs();
+        unsafe {
+            r.cs().modify(|w| {
+                w.set_ainsel(PIN::channel());
+                w.set_start_once(true)
+            });
+            Self::wait_for_ready().await;
+            r.result().read().result().into()
+        }
+    }
+
+    pub async fn read_temperature(&mut self) -> u16 {
+        let r = Self::regs();
+        unsafe {
+            r.cs().modify(|w| w.set_ts_en(true));
+            if !r.cs().read().ready() {
+                Self::wait_for_ready().await;
+            }
+            r.cs().modify(|w| {
+                w.set_ainsel(4);
+                w.set_start_once(true)
+            });
+            Self::wait_for_ready().await;
+            r.result().read().result().into()
+        }
+    }
+
+    pub fn blocking_read<PIN: Channel<Adc<'d>, ID = u8>>(&mut self, _pin: &mut PIN) -> u16 {
+        let r = Self::regs();
+        let ch = PIN::channel();
+        unsafe {
+            if ch == 4 {
+                r.cs().modify(|w| w.set_ts_en(true))
+            }
+            while !r.cs().read().ready() {}
+            r.cs().modify(|w| {
+                w.set_ainsel(ch);
+                w.set_start_once(true)
+            });
+            while !r.cs().read().ready() {}
+            r.result().read().result().into()
+        }
+    }
+
+    pub fn blocking_read_temperature(&mut self) -> u16 {
+        let r = Self::regs();
+        unsafe {
+            r.cs().modify(|w| w.set_ts_en(true));
+            while !r.cs().read().ready() {}
+            r.cs().modify(|w| {
+                w.set_ainsel(4);
+                w.set_start_once(true)
+            });
+            while !r.cs().read().ready() {}
+            r.result().read().result().into()
+        }
+    }
+}
+
+macro_rules! impl_pin {
+    ($pin:ident, $channel:expr) => {
+        impl Channel<Adc<'static>> for peripherals::$pin {
+            type ID = u8;
+            fn channel() -> u8 {
+                $channel
+            }
+        }
+    };
+}
+
+impl_pin!(PIN_26, 0);
+impl_pin!(PIN_27, 1);
+impl_pin!(PIN_28, 2);
+impl_pin!(PIN_29, 3);
+
+impl<WORD, PIN> OneShot<Adc<'static>, WORD, PIN> for Adc<'static>
+where
+    WORD: From<u16>,
+    PIN: Channel<Adc<'static>, ID = u8>,
+{
+    type Error = ();
+    fn read(&mut self, pin: &mut PIN) -> nb::Result<WORD, Self::Error> {
+        Ok(self.blocking_read(pin).into())
+    }
+}
diff --git a/embassy-rp/src/lib.rs b/embassy-rp/src/lib.rs
index f608f1768..6c91b1adc 100644
--- a/embassy-rp/src/lib.rs
+++ b/embassy-rp/src/lib.rs
@@ -6,6 +6,7 @@ pub(crate) mod fmt;
 
 mod intrinsics;
 
+pub mod adc;
 pub mod dma;
 pub mod gpio;
 pub mod i2c;
@@ -98,6 +99,8 @@ embassy_hal_common::peripherals! {
     RTC,
 
     FLASH,
+
+    ADC,
 }
 
 #[link_section = ".boot2"]
diff --git a/examples/rp/src/bin/adc.rs b/examples/rp/src/bin/adc.rs
new file mode 100644
index 000000000..2a9e93732
--- /dev/null
+++ b/examples/rp/src/bin/adc.rs
@@ -0,0 +1,33 @@
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+
+use defmt::*;
+use embassy_executor::Spawner;
+use embassy_rp::adc::{Adc, Config};
+use embassy_rp::interrupt;
+use embassy_time::{Duration, Timer};
+use {defmt_rtt as _, panic_probe as _};
+
+#[embassy_executor::main]
+async fn main(_spawner: Spawner) {
+    let p = embassy_rp::init(Default::default());
+    let irq = interrupt::take!(ADC_IRQ_FIFO);
+    let mut adc = Adc::new(p.ADC, irq, Config::default());
+
+    let mut p26 = p.PIN_26;
+    let mut p27 = p.PIN_27;
+    let mut p28 = p.PIN_28;
+
+    loop {
+        let level = adc.read(&mut p26).await;
+        info!("Pin 26 ADC: {}", level);
+        let level = adc.read(&mut p27).await;
+        info!("Pin 27 ADC: {}", level);
+        let level = adc.read(&mut p28).await;
+        info!("Pin 28 ADC: {}", level);
+        let temp = adc.read_temperature().await;
+        info!("Temp: {}", temp);
+        Timer::after(Duration::from_secs(1)).await;
+    }
+}