embassy-rp: Add support for color order to Pio::Ws2812

embassy-rp/CHANGELOG.md

@@ -16,6 +16,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - rp235x: use msplim for stack guard instead of MPU
 - Add reset_to_usb_boot for rp235x ([#4705](https://github.com/embassy-rs/embassy/pull/4705))
 - Add fix #4822 in PIO onewire. Change to disable the state machine before setting y register ([#4824](https://github.com/embassy-rs/embassy/pull/4824))
+- Add PIO::Ws2812 color order support
 
 ## 0.8.0 - 2025-08-26
 

embassy-rp/src/pio_programs/ws2812.rs

@@ -1,4 +1,4 @@
-//! [ws2812](https://www.sparkfun.com/datasheets/LCD/HD44780.pdf)
+//! [ws2812](https://www.sparkfun.com/categories/tags/ws2812)
 
 use embassy_time::Timer;
 use fixed::types::U24F8;
@@ -16,6 +16,54 @@ const T2: u8 = 5; // data bit
 const T3: u8 = 3; // stop bit
 const CYCLES_PER_BIT: u32 = (T1 + T2 + T3) as u32;
 
+/// Color orders for WS2812B, type RGB8
+pub trait RgbColorOrder {
+    /// Pack an 8-bit RGB color into a u32
+    fn pack(color: RGB8) -> u32;
+}
+
+/// Green, Red, Blue order is the common default for WS2812B
+pub struct Grb;
+impl RgbColorOrder for Grb {
+    /// Pack an 8-bit RGB color into a u32 in GRB order
+    fn pack(color: RGB8) -> u32 {
+        (u32::from(color.g) << 24) | (u32::from(color.r) << 16) | (u32::from(color.b) << 8)
+    }
+}
+
+/// Red, Green, Blue is used by some WS2812B implementations
+pub struct Rgb;
+impl RgbColorOrder for Rgb {
+    /// Pack an 8-bit RGB color into a u32 in RGB order
+    fn pack(color: RGB8) -> u32 {
+        (u32::from(color.r) << 24) | (u32::from(color.g) << 16) | (u32::from(color.b) << 8)
+    }
+}
+
+/// Color orders RGBW strips
+pub trait RgbwColorOrder {
+    /// Pack an RGB+W color into a u32
+    fn pack(color: RGBW<u8>) -> u32;
+}
+
+/// Green, Red, Blue, White order is the common default for RGBW strips
+pub struct Grbw;
+impl RgbwColorOrder for Grbw {
+    /// Pack an RGB+W color into a u32 in GRBW order
+    fn pack(color: RGBW<u8>) -> u32 {
+        (u32::from(color.g) << 24) | (u32::from(color.r) << 16) | (u32::from(color.b) << 8) | u32::from(color.a.0)
+    }
+}
+
+/// Red, Green, Blue, White order
+pub struct Rgbw;
+impl RgbwColorOrder for Rgbw {
+    /// Pack an RGB+W color into a u32 in RGBW order
+    fn pack(color: RGBW<u8>) -> u32 {
+        (u32::from(color.r) << 24) | (u32::from(color.g) << 16) | (u32::from(color.b) << 8) | u32::from(color.a.0)
+    }
+}
+
 /// This struct represents a ws2812 program loaded into pio instruction memory.
 pub struct PioWs2812Program<'a, PIO: Instance> {
     prg: LoadedProgram<'a, PIO>,
@@ -52,14 +100,36 @@ impl<'a, PIO: Instance> PioWs2812Program<'a, PIO> {
 
 /// Pio backed RGB ws2812 driver
 /// Const N is the number of ws2812 leds attached to this pin
-pub struct PioWs2812<'d, P: Instance, const S: usize, const N: usize> {
+pub struct PioWs2812<'d, P: Instance, const S: usize, const N: usize, ORDER>
+where
+    ORDER: RgbColorOrder,
+{
     dma: Peri<'d, AnyChannel>,
     sm: StateMachine<'d, P, S>,
+    _order: core::marker::PhantomData<ORDER>,
 }
 
-impl<'d, P: Instance, const S: usize, const N: usize> PioWs2812<'d, P, S, N> {
+impl<'d, P: Instance, const S: usize, const N: usize> PioWs2812<'d, P, S, N, Grb> {
     /// Configure a pio state machine to use the loaded ws2812 program.
+    /// Uses the default GRB order.
     pub fn new(
+        pio: &mut Common<'d, P>,
+        sm: StateMachine<'d, P, S>,
+        dma: Peri<'d, impl Channel>,
+        pin: Peri<'d, impl PioPin>,
+        program: &PioWs2812Program<'d, P>,
+    ) -> Self {
+        Self::with_color_order(pio, sm, dma, pin, program)
+    }
+}
+
+impl<'d, P: Instance, const S: usize, const N: usize, ORDER> PioWs2812<'d, P, S, N, ORDER>
+where
+    ORDER: RgbColorOrder,
+{
+    /// Configure a pio state machine to use the loaded ws2812 program.
+    /// Uses the specified color order.
+    pub fn with_color_order(
         pio: &mut Common<'d, P>,
         mut sm: StateMachine<'d, P, S>,
         dma: Peri<'d, impl Channel>,
@@ -93,16 +163,19 @@ impl<'d, P: Instance, const S: usize, const N: usize> PioWs2812<'d, P, S, N> {
         sm.set_config(&cfg);
         sm.set_enable(true);
 
-        Self { dma: dma.into(), sm }
+        Self {
+            dma: dma.into(),
+            sm,
+            _order: core::marker::PhantomData,
+        }
     }
 
     /// Write a buffer of [smart_leds::RGB8] to the ws2812 string
     pub async fn write(&mut self, colors: &[RGB8; N]) {
         // Precompute the word bytes from the colors
         let mut words = [0u32; N];
         for i in 0..N {
-            let word = (u32::from(colors[i].g) << 24) | (u32::from(colors[i].r) << 16) | (u32::from(colors[i].b) << 8);
-            words[i] = word;
+            words[i] = ORDER::pack(colors[i]);
         }
 
         // DMA transfer
@@ -115,14 +188,36 @@ impl<'d, P: Instance, const S: usize, const N: usize> PioWs2812<'d, P, S, N> {
 /// Pio backed RGBW ws2812 driver
 /// This version is intended for ws2812 leds with 4 addressable lights
 /// Const N is the number of ws2812 leds attached to this pin
-pub struct RgbwPioWs2812<'d, P: Instance, const S: usize, const N: usize> {
+pub struct RgbwPioWs2812<'d, P: Instance, const S: usize, const N: usize, ORDER>
+where
+    ORDER: RgbwColorOrder,
+{
     dma: Peri<'d, AnyChannel>,
     sm: StateMachine<'d, P, S>,
+    _order: core::marker::PhantomData<ORDER>,
 }
 
-impl<'d, P: Instance, const S: usize, const N: usize> RgbwPioWs2812<'d, P, S, N> {
+impl<'d, P: Instance, const S: usize, const N: usize> RgbwPioWs2812<'d, P, S, N, Grbw> {
     /// Configure a pio state machine to use the loaded ws2812 program.
+    /// Uses the default GRBW color order
     pub fn new(
+        pio: &mut Common<'d, P>,
+        sm: StateMachine<'d, P, S>,
+        dma: Peri<'d, impl Channel>,
+        pin: Peri<'d, impl PioPin>,
+        program: &PioWs2812Program<'d, P>,
+    ) -> Self {
+        Self::with_color_order(pio, sm, dma, pin, program)
+    }
+}
+
+impl<'d, P: Instance, const S: usize, const N: usize, ORDER> RgbwPioWs2812<'d, P, S, N, ORDER>
+where
+    ORDER: RgbwColorOrder,
+{
+    /// Configure a pio state machine to use the loaded ws2812 program.
+    /// Uses the specified color order
+    pub fn with_color_order(
         pio: &mut Common<'d, P>,
         mut sm: StateMachine<'d, P, S>,
         dma: Peri<'d, impl Channel>,
@@ -156,19 +251,19 @@ impl<'d, P: Instance, const S: usize, const N: usize> RgbwPioWs2812<'d, P, S, N>
         sm.set_config(&cfg);
         sm.set_enable(true);
 
-        Self { dma: dma.into(), sm }
+        Self {
+            dma: dma.into(),
+            sm,
+            _order: core::marker::PhantomData,
+        }
     }
 
     /// Write a buffer of [smart_leds::RGBW] to the ws2812 string
     pub async fn write(&mut self, colors: &[RGBW<u8>; N]) {
         // Precompute the word bytes from the colors
         let mut words = [0u32; N];
         for i in 0..N {
-            let word = (u32::from(colors[i].g) << 24)
-                | (u32::from(colors[i].r) << 16)
-                | (u32::from(colors[i].b) << 8)
-                | u32::from(colors[i].a.0);
-            words[i] = word;
+            words[i] = ORDER::pack(colors[i]);
         }
 
         // DMA transfer