Add support for the stm32 ltdc display peripheral

1 files changed, 443 insertions, 48 deletions

diff --git a/embassy-stm32/src/ltdc.rs b/embassy-stm32/src/ltdc.rs
index 481d77843..adc9b8862 100644
--- a/embassy-stm32/src/ltdc.rs
+++ b/embassy-stm32/src/ltdc.rs
@@ -1,19 +1,184 @@
-//! LTDC
-use core::marker::PhantomData;
+//! LTDC - LCD-TFT Display Controller
+//! See ST application note AN4861: Introduction to LCD-TFT display controller (LTDC) on STM32 MCUs for high level details
+//! This module was tested against the stm32h735g-dk using the RM0468 ST reference manual for detailed register information
 
-use crate::rcc::{self, RccPeripheral};
-use crate::{peripherals, Peripheral};
+use crate::{
+    gpio::{AfType, OutputType, Speed},
+    interrupt::{self, typelevel::Interrupt},
+    peripherals, rcc, Peripheral,
+};
+use core::{future::poll_fn, marker::PhantomData, task::Poll};
+use embassy_hal_internal::{into_ref, PeripheralRef};
+use embassy_sync::waitqueue::AtomicWaker;
+use stm32_metapac::ltdc::{
+    regs::Dccr,
+    vals::{Bf1, Bf2, Cfuif, Clif, Crrif, Cterrif, Pf, Vbr},
+};
+
+static LTDC_WAKER: AtomicWaker = AtomicWaker::new();
+
+/// LTDC error
+#[derive(Debug, PartialEq, Eq, Clone, Copy)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+pub enum Error {
+    /// FIFO underrun. Generated when a pixel is requested while the FIFO is empty
+    FifoUnderrun,
+    /// Transfer error. Generated when a bus error occurs
+    TransferError,
+}
+
+/// Display configuration parameters
+#[derive(Clone, Copy, Debug, PartialEq)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+pub struct LtdcConfiguration {
+    /// Active width in pixels
+    pub active_width: u16,
+    /// Active height in pixels
+    pub active_height: u16,
+
+    /// Horizontal back porch (in units of pixel clock period)
+    pub h_back_porch: u16,
+    /// Horizontal front porch (in units of pixel clock period)
+    pub h_front_porch: u16,
+    /// Vertical back porch (in units of horizontal scan line)
+    pub v_back_porch: u16,
+    /// Vertical front porch (in units of horizontal scan line)
+    pub v_front_porch: u16,
+
+    /// Horizontal synchronization width (in units of pixel clock period)
+    pub h_sync: u16,
+    /// Vertical synchronization height (in units of horizontal scan line)
+    pub v_sync: u16,
+
+    /// Horizontal synchronization polarity: `false`: active low, `true`: active high
+    pub h_sync_polarity: PolarityActive,
+    /// Vertical synchronization polarity: `false`: active low, `true`: active high
+    pub v_sync_polarity: PolarityActive,
+    /// Data enable polarity: `false`: active low, `true`: active high
+    pub data_enable_polarity: PolarityActive,
+    /// Pixel clock polarity: `false`: falling edge, `true`: rising edge
+    pub pixel_clock_polarity: PolarityEdge,
+}
+
+/// Edge polarity
+#[derive(Clone, Copy, Debug, PartialEq)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+pub enum PolarityEdge {
+    /// Falling edge
+    FallingEdge,
+    /// Rising edge
+    RisingEdge,
+}
+
+/// Active polarity
+#[derive(Clone, Copy, Debug, PartialEq)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+pub enum PolarityActive {
+    /// Active low
+    ActiveLow,
+    /// Active high
+    ActiveHigh,
+}
 
 /// LTDC driver.
 pub struct Ltdc<'d, T: Instance> {
-    _peri: PhantomData<&'d mut T>,
+    _peri: PeripheralRef<'d, T>,
+}
+
+/// LTDC interrupt handler.
+pub struct InterruptHandler<T: Instance> {
+    _phantom: PhantomData<T>,
+}
+
+/// 24 bit color
+#[derive(Debug, PartialEq, Eq, Clone, Copy, Default)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+pub struct RgbColor {
+    /// Red
+    pub red: u8,
+    /// Green
+    pub green: u8,
+    /// Blue
+    pub blue: u8,
+}
+
+/// Layer
+#[derive(Debug, PartialEq, Eq, Clone, Copy)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+pub struct LtdcLayerConfig {
+    /// Layer number
+    pub layer: LtdcLayer,
+    /// Pixel format
+    pub pixel_format: PixelFormat,
+    /// Window left x in pixels
+    pub window_x0: u16,
+    /// Window right x in pixels
+    pub window_x1: u16,
+    /// Window top y in pixels
+    pub window_y0: u16,
+    /// Window bottom y in pixels
+    pub window_y1: u16,
+}
+
+/// Pixel format
+#[repr(u8)]
+#[derive(Debug, PartialEq, Eq, Clone, Copy)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+pub enum PixelFormat {
+    /// ARGB8888
+    ARGB8888 = Pf::ARGB8888 as u8,
+    /// RGB888
+    RGB888 = Pf::RGB888 as u8,
+    /// RGB565
+    RGB565 = Pf::RGB565 as u8,
+    /// ARGB1555
+    ARGB1555 = Pf::ARGB1555 as u8,
+    /// ARGB4444
+    ARGB4444 = Pf::ARGB4444 as u8,
+    /// L8 (8-bit luminance)
+    L8 = Pf::L8 as u8,
+    /// AL44 (4-bit alpha, 4-bit luminance
+    AL44 = Pf::AL44 as u8,
+    /// AL88 (8-bit alpha, 8-bit luminance)
+    AL88 = Pf::AL88 as u8,
+}
+
+impl PixelFormat {
+    /// Number of bytes per pixel
+    pub fn bytes_per_pixel(&self) -> usize {
+        match self {
+            PixelFormat::ARGB8888 => 4,
+            PixelFormat::RGB888 => 3,
+            PixelFormat::RGB565 | PixelFormat::ARGB4444 | PixelFormat::ARGB1555 | PixelFormat::AL88 => 2,
+            PixelFormat::AL44 | PixelFormat::L8 => 1,
+        }
+    }
+}
+
+/// Ltdc Blending Layer
+#[repr(usize)]
+#[derive(Debug, PartialEq, Eq, Clone, Copy)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+pub enum LtdcLayer {
+    /// Bottom layer
+    Layer1 = 0,
+    /// Top layer
+    Layer2 = 1,
+}
+
+impl<T: Instance> interrupt::typelevel::Handler<T::Interrupt> for InterruptHandler<T> {
+    unsafe fn on_interrupt() {
+        cortex_m::asm::dsb();
+        Ltdc::<T>::enable_interrupts(false);
+        LTDC_WAKER.wake();
+    }
 }
 
 impl<'d, T: Instance> Ltdc<'d, T> {
-    /// Note: Full-Duplex modes are not supported at this time
+    /// Create a new LTDC driver. 8 pins per color channel for blue, green and red
     pub fn new(
-        _peri: impl Peripheral<P = T> + 'd,
-        /*
+        peri: impl Peripheral<P = T> + 'd,
+        _irq: impl interrupt::typelevel::Binding<T::Interrupt, InterruptHandler<T>> + 'd,
         clk: impl Peripheral<P = impl ClkPin<T>> + 'd,
         hsync: impl Peripheral<P = impl HsyncPin<T>> + 'd,
         vsync: impl Peripheral<P = impl VsyncPin<T>> + 'd,
@@ -41,49 +206,274 @@ impl<'d, T: Instance> Ltdc<'d, T> {
         r5: impl Peripheral<P = impl R5Pin<T>> + 'd,
         r6: impl Peripheral<P = impl R6Pin<T>> + 'd,
         r7: impl Peripheral<P = impl R7Pin<T>> + 'd,
-        */
     ) -> Self {
-        //into_ref!(clk);
-
-        critical_section::with(|_cs| {
-            // RM says the pllsaidivr should only be changed when pllsai is off. But this could have other unintended side effects. So let's just give it a try like this.
-            // According to the debugger, this bit gets set, anyway.
-            #[cfg(stm32f7)]
-            stm32_metapac::RCC
-                .dckcfgr1()
-                .modify(|w| w.set_pllsaidivr(stm32_metapac::rcc::vals::Pllsaidivr::DIV2));
-
-            // It is set to RCC_PLLSAIDIVR_2 in ST's BSP example for the STM32469I-DISCO.
-            #[cfg(not(any(stm32f7, stm32u5)))]
-            stm32_metapac::RCC
-                .dckcfgr()
-                .modify(|w| w.set_pllsaidivr(stm32_metapac::rcc::vals::Pllsaidivr::DIV2));
+        rcc::enable_and_reset::<T>();
+
+        into_ref!(peri);
+        new_pin!(clk, AfType::output(OutputType::PushPull, Speed::VeryHigh));
+        new_pin!(hsync, AfType::output(OutputType::PushPull, Speed::VeryHigh));
+        new_pin!(vsync, AfType::output(OutputType::PushPull, Speed::VeryHigh));
+        new_pin!(b0, AfType::output(OutputType::PushPull, Speed::VeryHigh));
+        new_pin!(b1, AfType::output(OutputType::PushPull, Speed::VeryHigh));
+        new_pin!(b2, AfType::output(OutputType::PushPull, Speed::VeryHigh));
+        new_pin!(b3, AfType::output(OutputType::PushPull, Speed::VeryHigh));
+        new_pin!(b4, AfType::output(OutputType::PushPull, Speed::VeryHigh));
+        new_pin!(b5, AfType::output(OutputType::PushPull, Speed::VeryHigh));
+        new_pin!(b6, AfType::output(OutputType::PushPull, Speed::VeryHigh));
+        new_pin!(b7, AfType::output(OutputType::PushPull, Speed::VeryHigh));
+        new_pin!(g0, AfType::output(OutputType::PushPull, Speed::VeryHigh));
+        new_pin!(g1, AfType::output(OutputType::PushPull, Speed::VeryHigh));
+        new_pin!(g2, AfType::output(OutputType::PushPull, Speed::VeryHigh));
+        new_pin!(g3, AfType::output(OutputType::PushPull, Speed::VeryHigh));
+        new_pin!(g4, AfType::output(OutputType::PushPull, Speed::VeryHigh));
+        new_pin!(g5, AfType::output(OutputType::PushPull, Speed::VeryHigh));
+        new_pin!(g6, AfType::output(OutputType::PushPull, Speed::VeryHigh));
+        new_pin!(g7, AfType::output(OutputType::PushPull, Speed::VeryHigh));
+        new_pin!(r0, AfType::output(OutputType::PushPull, Speed::VeryHigh));
+        new_pin!(r1, AfType::output(OutputType::PushPull, Speed::VeryHigh));
+        new_pin!(r2, AfType::output(OutputType::PushPull, Speed::VeryHigh));
+        new_pin!(r3, AfType::output(OutputType::PushPull, Speed::VeryHigh));
+        new_pin!(r4, AfType::output(OutputType::PushPull, Speed::VeryHigh));
+        new_pin!(r5, AfType::output(OutputType::PushPull, Speed::VeryHigh));
+        new_pin!(r6, AfType::output(OutputType::PushPull, Speed::VeryHigh));
+        new_pin!(r7, AfType::output(OutputType::PushPull, Speed::VeryHigh));
+
+        Self { _peri: peri }
+    }
+
+    fn clear_interrupt_flags() {
+        T::regs().icr().write(|w| {
+            w.set_cfuif(Cfuif::CLEAR);
+            w.set_clif(Clif::CLEAR);
+            w.set_crrif(Crrif::CLEAR);
+            w.set_cterrif(Cterrif::CLEAR);
         });
+    }
 
-        rcc::enable_and_reset::<T>();
+    fn enable_interrupts(enable: bool) {
+        T::regs().ier().write(|w| {
+            w.set_fuie(enable);
+            w.set_lie(false); // we are not interested in the line interrupt enable event
+            w.set_rrie(enable);
+            w.set_terrie(enable)
+        });
+
+        // enable interrupts for LTDC peripheral
+        T::Interrupt::unpend();
+        if enable {
+            unsafe { T::Interrupt::enable() };
+        } else {
+            T::Interrupt::disable()
+        }
+    }
 
-        //new_pin!(clk, AfType::output(OutputType::PushPull, Speed::VeryHigh));
+    /// Set the current buffer. The async function will return when buffer has been completely copied to the LCD screen
+    /// frame_buffer_addr is a pointer to memory that should not move (best to make it static)
+    pub async fn set_buffer(&mut self, layer: LtdcLayer, frame_buffer_addr: *const ()) -> Result<(), Error> {
+        let mut bits = T::regs().isr().read();
 
-        // Set Tearing Enable pin according to CubeMx example
-        //te.set_as_af_pull(te.af_num(), AfType::output(OutputType::PushPull, Speed::Low));
-        /*
-                T::regs().wcr().modify(|w| {
-                    w.set_dsien(true);
+        // if all clear
+        if !bits.fuif() && !bits.lif() && !bits.rrif() && !bits.terrif() {
+            // wait for interrupt
+            poll_fn(|cx| {
+                // quick check to avoid registration if already done.
+                let bits = T::regs().isr().read();
+                if bits.fuif() || bits.lif() || bits.rrif() || bits.terrif() {
+                    return Poll::Ready(());
+                }
+
+                LTDC_WAKER.register(cx.waker());
+                Self::clear_interrupt_flags(); // don't poison the request with old flags
+                Self::enable_interrupts(true);
+
+                // set the new frame buffer address
+                let layer = T::regs().layer(layer as usize);
+                layer.cfbar().modify(|w| w.set_cfbadd(frame_buffer_addr as u32));
+
+                // configure a shadow reload for the next blanking period
+                T::regs().srcr().write(|w| {
+                    w.set_vbr(Vbr::RELOAD);
                 });
-        */
-        Self { _peri: PhantomData }
+
+                // need to check condition after register to avoid a race
+                // condition that would result in lost notifications.
+                let bits = T::regs().isr().read();
+                if bits.fuif() || bits.lif() || bits.rrif() || bits.terrif() {
+                    Poll::Ready(())
+                } else {
+                    Poll::Pending
+                }
+            })
+            .await;
+
+            // re-read the status register after wait.
+            bits = T::regs().isr().read();
+        }
+
+        let result = if bits.fuif() {
+            Err(Error::FifoUnderrun)
+        } else if bits.terrif() {
+            Err(Error::TransferError)
+        } else if bits.lif() {
+            panic!("line interrupt event is disabled")
+        } else if bits.rrif() {
+            // register reload flag is expected
+            Ok(())
+        } else {
+            unreachable!("all interrupt status values checked")
+        };
+
+        Self::clear_interrupt_flags();
+        result
     }
 
-    /// Set the enable bit in the control register and assert that it has been enabled
-    pub fn enable(&mut self) {
-        T::regs().gcr().modify(|w| w.set_ltdcen(true));
-        assert!(T::regs().gcr().read().ltdcen())
+    /// Initialize the display
+    pub fn init(&mut self, config: &LtdcConfiguration) {
+        use stm32_metapac::ltdc::vals::{Depol, Hspol, Pcpol, Vspol};
+        let ltdc = T::regs();
+
+        // check bus access
+        assert!(ltdc.gcr().read().0 == 0x2220); // reset value
+
+        // configure the HS, VS, DE and PC polarity
+        ltdc.gcr().modify(|w| {
+            w.set_hspol(match config.h_sync_polarity {
+                PolarityActive::ActiveHigh => Hspol::ACTIVEHIGH,
+                PolarityActive::ActiveLow => Hspol::ACTIVELOW,
+            });
+
+            w.set_vspol(match config.v_sync_polarity {
+                PolarityActive::ActiveHigh => Vspol::ACTIVEHIGH,
+                PolarityActive::ActiveLow => Vspol::ACTIVELOW,
+            });
+
+            w.set_depol(match config.data_enable_polarity {
+                PolarityActive::ActiveHigh => Depol::ACTIVEHIGH,
+                PolarityActive::ActiveLow => Depol::ACTIVELOW,
+            });
+
+            w.set_pcpol(match config.pixel_clock_polarity {
+                PolarityEdge::RisingEdge => Pcpol::RISINGEDGE,
+                PolarityEdge::FallingEdge => Pcpol::FALLINGEDGE,
+            });
+        });
+
+        // set synchronization pulse width
+        ltdc.sscr().modify(|w| {
+            w.set_vsh(config.v_sync - 1);
+            w.set_hsw(config.h_sync - 1);
+        });
+
+        // set accumulated back porch
+        ltdc.bpcr().modify(|w| {
+            w.set_avbp(config.v_sync + config.v_back_porch - 1);
+            w.set_ahbp(config.h_sync + config.h_back_porch - 1);
+        });
+
+        // set accumulated active width
+        let aa_height = config.v_sync + config.v_back_porch + config.active_height - 1;
+        let aa_width = config.h_sync + config.h_back_porch + config.active_width - 1;
+        ltdc.awcr().modify(|w| {
+            w.set_aah(aa_height);
+            w.set_aaw(aa_width);
+        });
+
+        // set total width and height
+        let total_height: u16 = config.v_sync + config.v_back_porch + config.active_height + config.v_front_porch - 1;
+        let total_width: u16 = config.h_sync + config.h_back_porch + config.active_width + config.h_front_porch - 1;
+        ltdc.twcr().modify(|w| {
+            w.set_totalh(total_height);
+            w.set_totalw(total_width)
+        });
+
+        // set the background color value to black
+        ltdc.bccr().modify(|w| {
+            w.set_bcred(0);
+            w.set_bcgreen(0);
+            w.set_bcblue(0);
+        });
+
+        // enable LTDC by setting LTDCEN bit
+        ltdc.gcr().modify(|w| {
+            w.set_ltdcen(true);
+        });
     }
 
-    /// Unset the enable bit in the control register and assert that it has been disabled
-    pub fn disable(&mut self) {
-        T::regs().gcr().modify(|w| w.set_ltdcen(false));
-        assert!(!T::regs().gcr().read().ltdcen())
+    /// Enable the layer
+    ///
+    /// clut - color look-up table applies to L8, AL44 and AL88 pixel format and will default to greyscale if None supplied and these pixel formats are used
+    pub fn enable_layer(&mut self, layer_config: &LtdcLayerConfig, clut: Option<&[RgbColor]>) {
+        let ltdc = T::regs();
+        let layer = ltdc.layer(layer_config.layer as usize);
+
+        // 256 color look-up table for L8, AL88 and AL88 pixel formats
+        if let Some(clut) = clut {
+            assert_eq!(clut.len(), 256, "Color lookup table must be exactly 256 in length");
+            for (index, color) in clut.iter().enumerate() {
+                layer.clutwr().write(|w| {
+                    w.set_clutadd(index as u8);
+                    w.set_red(color.red);
+                    w.set_green(color.green);
+                    w.set_blue(color.blue);
+                });
+            }
+        }
+
+        // configure the horizontal start and stop position
+        let h_win_start = layer_config.window_x0 + ltdc.bpcr().read().ahbp() + 1;
+        let h_win_stop = layer_config.window_x1 + ltdc.bpcr().read().ahbp();
+        layer.whpcr().write(|w| {
+            w.set_whstpos(h_win_start);
+            w.set_whsppos(h_win_stop);
+        });
+
+        // configure the vertical start and stop position
+        let v_win_start = layer_config.window_y0 + ltdc.bpcr().read().avbp() + 1;
+        let v_win_stop = layer_config.window_y1 + ltdc.bpcr().read().avbp();
+        layer.wvpcr().write(|w| {
+            w.set_wvstpos(v_win_start);
+            w.set_wvsppos(v_win_stop)
+        });
+
+        // set the pixel format
+        layer
+            .pfcr()
+            .write(|w| w.set_pf(Pf::from_bits(layer_config.pixel_format as u8)));
+
+        // set the default color value to transparent black
+        layer.dccr().write_value(Dccr::default());
+
+        // set the global constant alpha value
+        let alpha = 0xFF;
+        layer.cacr().write(|w| w.set_consta(alpha));
+
+        // set the blending factors.
+        layer.bfcr().modify(|w| {
+            w.set_bf1(Bf1::PIXEL);
+            w.set_bf2(Bf2::PIXEL);
+        });
+
+        // calculate framebuffer pixel size in bytes
+        let bytes_per_pixel = layer_config.pixel_format.bytes_per_pixel() as u16;
+        let width = layer_config.window_x1 - layer_config.window_x0;
+        let height = layer_config.window_y1 - layer_config.window_y0;
+
+        // framebuffer pitch and line length
+        layer.cfblr().modify(|w| {
+            w.set_cfbp(width * bytes_per_pixel);
+            w.set_cfbll(width * bytes_per_pixel + 7);
+        });
+
+        // framebuffer line number
+        layer.cfblnr().modify(|w| w.set_cfblnbr(height));
+
+        // enable LTDC_Layer by setting LEN bit
+        layer.cr().modify(|w| {
+            if clut.is_some() {
+                w.set_cluten(true);
+            }
+            w.set_len(true);
+        });
     }
 }
 
@@ -95,9 +485,12 @@ trait SealedInstance: crate::rcc::SealedRccPeripheral {
     fn regs() -> crate::pac::ltdc::Ltdc;
 }
 
-/// DSI instance trait.
+/// LTDC instance trait.
 #[allow(private_bounds)]
-pub trait Instance: SealedInstance + RccPeripheral + 'static {}
+pub trait Instance: SealedInstance + Peripheral<P = Self> + crate::rcc::RccPeripheral + 'static + Send {
+    /// Interrupt for this LTDC instance.
+    type Interrupt: interrupt::typelevel::Interrupt;
+}
 
 pin_trait!(ClkPin, Instance);
 pin_trait!(HsyncPin, Instance);
@@ -128,14 +521,16 @@ pin_trait!(B5Pin, Instance);
 pin_trait!(B6Pin, Instance);
 pin_trait!(B7Pin, Instance);
 
-foreach_peripheral!(
-    (ltdc, $inst:ident) => {
-        impl crate::ltdc::SealedInstance for peripherals::$inst {
+foreach_interrupt!(
+    ($inst:ident, ltdc, LTDC, GLOBAL, $irq:ident) => {
+        impl Instance for peripherals::$inst {
+            type Interrupt = crate::interrupt::typelevel::$irq;
+        }
+
+        impl SealedInstance for peripherals::$inst {
             fn regs() -> crate::pac::ltdc::Ltdc {
                 crate::pac::$inst
             }
         }
-
-        impl crate::ltdc::Instance for peripherals::$inst {}
     };
 );