Implement the embedded-hal Read trait for the RNG peripheral

esp-hal-common/src/lib.rs

@@ -36,6 +36,7 @@ pub mod i2c;
 #[cfg_attr(feature = "esp32c3", path = "interrupt/riscv.rs")]
 pub mod interrupt;
 pub mod prelude;
+pub mod rng;
 #[cfg(not(feature = "esp32c3"))]
 pub mod rtc_cntl;
 pub mod serial;
@@ -46,6 +47,7 @@ pub use gpio::*;
 pub use interrupt::*;
 use procmacros;
 pub use procmacros::ram;
+pub use rng::Rng;
 #[cfg(not(feature = "esp32c3"))]
 pub use rtc_cntl::RtcCntl;
 pub use serial::Serial;

esp-hal-common/src/rng.rs

@@ -0,0 +1,29 @@
+use core::convert::Infallible;
+
+use embedded_hal::blocking::rng::Read;
+
+use crate::pac::RNG;
+
+#[derive(Debug)]
+pub struct Rng {
+    rng: RNG,
+}
+
+impl Rng {
+    pub fn new(rng: RNG) -> Self {
+        Self { rng }
+    }
+}
+
+impl Read for Rng {
+    type Error = Infallible;
+
+    fn read(&mut self, buffer: &mut [u8]) -> Result<(), Self::Error> {
+        for chunk in buffer.chunks_mut(4) {
+            let bytes = self.rng.data.read().bits().to_le_bytes();
+            chunk.copy_from_slice(&bytes[..chunk.len()]);
+        }
+
+        Ok(())
+    }
+}

esp32-hal/src/lib.rs

@@ -1,7 +1,7 @@
 #![no_std]
 
 pub use embedded_hal as ehal;
-pub use esp_hal_common::{i2c, pac, prelude, Delay, RtcCntl, Serial, Timer};
+pub use esp_hal_common::{i2c, pac, prelude, Delay, Rng, RtcCntl, Serial, Timer};
 
 pub use self::gpio::IO;
 

esp32c3-hal/src/lib.rs

@@ -1,7 +1,7 @@
 #![no_std]
 
 pub use embedded_hal as ehal;
-pub use esp_hal_common::{i2c, pac, prelude, Delay, Serial, Timer};
+pub use esp_hal_common::{i2c, pac, prelude, Delay, Rng, Serial, Timer};
 #[cfg(not(feature = "normalboot"))]
 use riscv_rt::pre_init;
 

esp32s2-hal/src/lib.rs

@@ -7,6 +7,7 @@ pub use esp_hal_common::{
     prelude,
     ram,
     Delay,
+    Rng,
     RtcCntl,
     Serial,
     Timer,

esp32s3-hal/src/lib.rs

@@ -1,7 +1,7 @@
 #![no_std]
 
 pub use embedded_hal as ehal;
-pub use esp_hal_common::{i2c, pac, prelude, ram, Delay, RtcCntl, Serial, Timer};
+pub use esp_hal_common::{i2c, pac, prelude, ram, Delay, Rng, RtcCntl, Serial, Timer};
 
 pub use self::gpio::IO;