Issue 1974 add sai/mod file

1 files changed, 888 insertions, 0 deletions

diff --git a/embassy-stm32/src/sai/mod.rs b/embassy-stm32/src/sai/mod.rs
new file mode 100644
index 000000000..1fcee226d
--- /dev/null
+++ b/embassy-stm32/src/sai/mod.rs
@@ -0,0 +1,888 @@
+#![macro_use]
+
+use embassy_embedded_hal::SetConfig;
+use embassy_hal_internal::{into_ref, PeripheralRef};
+
+use crate::dma::{Channel, ReadableRingBuffer, TransferOptions, WritableRingBuffer};
+use crate::gpio::sealed::{AFType, Pin as _};
+use crate::gpio::AnyPin;
+use crate::pac::sai::{vals, Sai as Regs};
+use crate::rcc::RccPeripheral;
+use crate::time::Hertz;
+use crate::{peripherals, Peripheral};
+
+pub use crate::dma::word;
+
+#[derive(Debug)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+pub enum Error {
+    NotATransmitter,
+    NotAReceiver,
+}
+
+#[derive(Copy, Clone)]
+pub enum SyncBlock {
+    None,
+    Sai1BlockA,
+    Sai1BlockB,
+    Sai2BlockA,
+    Sai2BlockB,
+}
+
+#[derive(Copy, Clone)]
+pub enum SyncIn {
+    None,
+    ChannelZero,
+    ChannelOne,
+}
+
+#[derive(Copy, Clone)]
+pub enum Mode {
+    Master,
+    Slave,
+}
+
+#[derive(Copy, Clone)]
+enum TxRx {
+    Transmiter,
+    Receiver,
+}
+
+impl Mode {
+    #[cfg(any(sai_v1, sai_v2, sai_v3, sai_v4))]
+    const fn mode(&self, tx_rx: TxRx) -> vals::Mode {
+        match tx_rx {
+            TxRx::Transmiter => match self {
+                Mode::Master => vals::Mode::MASTERTX,
+                Mode::Slave => vals::Mode::SLAVETX,
+            },
+            TxRx::Receiver => match self {
+                Mode::Master => vals::Mode::MASTERRX,
+                Mode::Slave => vals::Mode::SLAVERX,
+            },
+        }
+    }
+}
+
+#[derive(Copy, Clone)]
+pub enum SlotSize {
+    DataSize,
+    /// 16 bit data length on 16 bit wide channel
+    Channel16,
+    /// 16 bit data length on 32 bit wide channel
+    Channel32,
+}
+
+impl SlotSize {
+    #[cfg(any(sai_v1, sai_v2, sai_v3, sai_v4))]
+    pub const fn slotsz(&self) -> vals::Slotsz {
+        match self {
+            SlotSize::DataSize => vals::Slotsz::DATASIZE,
+            SlotSize::Channel16 => vals::Slotsz::BIT16,
+            SlotSize::Channel32 => vals::Slotsz::BIT32,
+        }
+    }
+}
+
+#[derive(Copy, Clone)]
+pub enum DataSize {
+    Data8,
+    Data10,
+    Data16,
+    Data20,
+    Data24,
+    Data32,
+}
+
+impl DataSize {
+    #[cfg(any(sai_v1, sai_v2, sai_v3, sai_v4))]
+    pub const fn ds(&self) -> vals::Ds {
+        match self {
+            DataSize::Data8 => vals::Ds::BIT8,
+            DataSize::Data10 => vals::Ds::BIT10,
+            DataSize::Data16 => vals::Ds::BIT16,
+            DataSize::Data20 => vals::Ds::BIT20,
+            DataSize::Data24 => vals::Ds::BIT24,
+            DataSize::Data32 => vals::Ds::BIT32,
+        }
+    }
+}
+
+#[derive(Copy, Clone)]
+pub enum FifoThreshold {
+    Empty,
+    Quarter,
+    Half,
+    ThreeQuarters,
+    Full,
+}
+
+impl FifoThreshold {
+    #[cfg(any(sai_v1, sai_v2, sai_v3, sai_v4))]
+    pub const fn fth(&self) -> vals::Fth {
+        match self {
+            FifoThreshold::Empty => vals::Fth::EMPTY,
+            FifoThreshold::Quarter => vals::Fth::QUARTER1,
+            FifoThreshold::Half => vals::Fth::QUARTER2,
+            FifoThreshold::ThreeQuarters => vals::Fth::QUARTER3,
+            FifoThreshold::Full => vals::Fth::FULL,
+        }
+    }
+}
+
+#[derive(Copy, Clone)]
+pub enum FifoLevel {
+    Empty,
+    FirstQuarter,
+    SecondQuarter,
+    ThirdQuarter,
+    FourthQuarter,
+    Full,
+}
+
+#[cfg(any(sai_v1, sai_v2, sai_v3, sai_v4))]
+impl From<vals::Flvl> for FifoLevel {
+    fn from(flvl: vals::Flvl) -> Self {
+        match flvl {
+            vals::Flvl::EMPTY => FifoLevel::Empty,
+            vals::Flvl::QUARTER1 => FifoLevel::FirstQuarter,
+            vals::Flvl::QUARTER2 => FifoLevel::SecondQuarter,
+            vals::Flvl::QUARTER3 => FifoLevel::ThirdQuarter,
+            vals::Flvl::QUARTER4 => FifoLevel::FourthQuarter,
+            vals::Flvl::FULL => FifoLevel::Full,
+            _ => FifoLevel::Empty,
+        }
+    }
+}
+
+#[derive(Copy, Clone)]
+pub enum MuteDetection {
+    NoMute,
+    Mute,
+}
+
+#[derive(Copy, Clone)]
+pub enum MuteValue {
+    Zero,
+    LastValue,
+}
+
+impl MuteValue {
+    #[cfg(any(sai_v1, sai_v2, sai_v3, sai_v4))]
+    pub const fn muteval(&self) -> vals::Muteval {
+        match self {
+            MuteValue::Zero => vals::Muteval::SENDZERO,
+            MuteValue::LastValue => vals::Muteval::SENDLAST,
+        }
+    }
+}
+
+#[derive(Copy, Clone)]
+pub enum OverUnderStatus {
+    NoError,
+    OverUnderRunDetected,
+}
+
+#[derive(Copy, Clone)]
+pub enum Protocol {
+    Free,
+    Spdif,
+    Ac97,
+}
+
+impl Protocol {
+    #[cfg(any(sai_v1, sai_v2, sai_v3, sai_v4))]
+    pub const fn prtcfg(&self) -> vals::Prtcfg {
+        match self {
+            Protocol::Free => vals::Prtcfg::FREE,
+            Protocol::Spdif => vals::Prtcfg::SPDIF,
+            Protocol::Ac97 => vals::Prtcfg::AC97,
+        }
+    }
+}
+
+#[derive(Copy, Clone)]
+pub enum SyncEnable {
+    Asynchronous,
+    /// Syncs with the other A/B sub-block within the SAI unit
+    Internal,
+    /// Syncs with a sub-block in the other SAI unit - use set_sync_output() and set_sync_input()
+    External,
+}
+
+impl SyncEnable {
+    #[cfg(any(sai_v1, sai_v2, sai_v3, sai_v4))]
+    pub const fn syncen(&self) -> vals::Syncen {
+        match self {
+            SyncEnable::Asynchronous => vals::Syncen::ASYNCHRONOUS,
+            SyncEnable::Internal => vals::Syncen::INTERNAL,
+            SyncEnable::External => vals::Syncen::EXTERNAL,
+        }
+    }
+}
+
+#[derive(Copy, Clone, PartialEq)]
+pub enum StereoMono {
+    Stereo,
+    Mono,
+}
+
+impl StereoMono {
+    #[cfg(any(sai_v1, sai_v2, sai_v3, sai_v4))]
+    pub const fn mono(&self) -> vals::Mono {
+        match self {
+            StereoMono::Stereo => vals::Mono::STEREO,
+            StereoMono::Mono => vals::Mono::MONO,
+        }
+    }
+}
+
+#[derive(Copy, Clone)]
+pub enum BitOrder {
+    LsbFirst,
+    MsbFirst,
+}
+
+impl BitOrder {
+    #[cfg(any(sai_v1, sai_v2, sai_v3, sai_v4))]
+    pub const fn lsbfirst(&self) -> vals::Lsbfirst {
+        match self {
+            BitOrder::LsbFirst => vals::Lsbfirst::LSBFIRST,
+            BitOrder::MsbFirst => vals::Lsbfirst::MSBFIRST,
+        }
+    }
+}
+
+#[derive(Copy, Clone)]
+pub enum FrameSyncOffset {
+    /// This is used in modes other than standard I2S phillips mode
+    OnFirstBit,
+    /// This is used in standard I2S phillips mode
+    BeforeFirstBit,
+}
+
+impl FrameSyncOffset {
+    #[cfg(any(sai_v1, sai_v2, sai_v3, sai_v4))]
+    pub const fn fsoff(&self) -> vals::Fsoff {
+        match self {
+            FrameSyncOffset::OnFirstBit => vals::Fsoff::ONFIRST,
+            FrameSyncOffset::BeforeFirstBit => vals::Fsoff::BEFOREFIRST,
+        }
+    }
+}
+
+#[derive(Copy, Clone)]
+pub enum FrameSyncPolarity {
+    ActiveLow,
+    ActiveHigh,
+}
+
+impl FrameSyncPolarity {
+    #[cfg(any(sai_v1, sai_v2, sai_v3, sai_v4))]
+    pub const fn fspol(&self) -> vals::Fspol {
+        match self {
+            FrameSyncPolarity::ActiveLow => vals::Fspol::FALLINGEDGE,
+            FrameSyncPolarity::ActiveHigh => vals::Fspol::RISINGEDGE,
+        }
+    }
+}
+
+#[derive(Copy, Clone)]
+pub enum FrameSyncDefinition {
+    StartOfFrame,
+    ChannelIdentification,
+}
+
+impl FrameSyncDefinition {
+    #[cfg(any(sai_v1, sai_v2, sai_v3, sai_v4))]
+    pub const fn fsdef(&self) -> bool {
+        match self {
+            FrameSyncDefinition::StartOfFrame => false,
+            FrameSyncDefinition::ChannelIdentification => true,
+        }
+    }
+}
+
+#[derive(Copy, Clone)]
+pub enum ClockStrobe {
+    Falling,
+    Rising,
+}
+
+impl ClockStrobe {
+    #[cfg(any(sai_v1, sai_v2, sai_v3, sai_v4))]
+    pub const fn ckstr(&self) -> vals::Ckstr {
+        match self {
+            ClockStrobe::Falling => vals::Ckstr::FALLINGEDGE,
+            ClockStrobe::Rising => vals::Ckstr::RISINGEDGE,
+        }
+    }
+}
+
+#[derive(Copy, Clone)]
+pub enum ComplementFormat {
+    OnesComplement,
+    TwosComplement,
+}
+
+impl ComplementFormat {
+    #[cfg(any(sai_v1, sai_v2, sai_v3, sai_v4))]
+    pub const fn cpl(&self) -> vals::Cpl {
+        match self {
+            ComplementFormat::OnesComplement => vals::Cpl::ONESCOMPLEMENT,
+            ComplementFormat::TwosComplement => vals::Cpl::TWOSCOMPLEMENT,
+        }
+    }
+}
+
+#[derive(Copy, Clone)]
+pub enum Companding {
+    None,
+    MuLaw,
+    ALaw,
+}
+
+impl Companding {
+    #[cfg(any(sai_v1, sai_v2, sai_v3, sai_v4))]
+    pub const fn comp(&self) -> vals::Comp {
+        match self {
+            Companding::None => vals::Comp::NOCOMPANDING,
+            Companding::MuLaw => vals::Comp::MULAW,
+            Companding::ALaw => vals::Comp::ALAW,
+        }
+    }
+}
+
+#[derive(Copy, Clone)]
+pub enum OutputDrive {
+    OnStart,
+    Immediately,
+}
+
+impl OutputDrive {
+    #[cfg(any(sai_v1, sai_v2, sai_v3, sai_v4))]
+    pub const fn outdriv(&self) -> vals::Outdriv {
+        match self {
+            OutputDrive::OnStart => vals::Outdriv::ONSTART,
+            OutputDrive::Immediately => vals::Outdriv::IMMEDIATELY,
+        }
+    }
+}
+
+#[derive(Copy, Clone, PartialEq)]
+pub enum MasterClockDivider {
+    MasterClockDisabled,
+    Div1,
+    Div2,
+    Div4,
+    Div6,
+    Div8,
+    Div10,
+    Div12,
+    Div14,
+    Div16,
+    Div18,
+    Div20,
+    Div22,
+    Div24,
+    Div26,
+    Div28,
+    Div30,
+}
+
+impl MasterClockDivider {
+    #[cfg(any(sai_v1, sai_v2, sai_v3, sai_v4))]
+    pub const fn mckdiv(&self) -> u8 {
+        match self {
+            MasterClockDivider::MasterClockDisabled => 0,
+            MasterClockDivider::Div1 => 0,
+            MasterClockDivider::Div2 => 1,
+            MasterClockDivider::Div4 => 2,
+            MasterClockDivider::Div6 => 3,
+            MasterClockDivider::Div8 => 4,
+            MasterClockDivider::Div10 => 5,
+            MasterClockDivider::Div12 => 6,
+            MasterClockDivider::Div14 => 7,
+            MasterClockDivider::Div16 => 8,
+            MasterClockDivider::Div18 => 9,
+            MasterClockDivider::Div20 => 10,
+            MasterClockDivider::Div22 => 11,
+            MasterClockDivider::Div24 => 12,
+            MasterClockDivider::Div26 => 13,
+            MasterClockDivider::Div28 => 14,
+            MasterClockDivider::Div30 => 15,
+        }
+    }
+}
+
+/// [`SAI`] configuration.
+#[non_exhaustive]
+#[derive(Copy, Clone)]
+pub struct Config {
+    pub mode: Mode,
+    pub sync_enable: SyncEnable,
+    pub is_sync_output: bool,
+    pub protocol: Protocol,
+    pub slot_size: SlotSize,
+    pub slot_count: word::U4,
+    pub slot_enable: u16,
+    pub first_bit_offset: word::U5,
+    pub data_size: DataSize,
+    pub stereo_mono: StereoMono,
+    pub bit_order: BitOrder,
+    pub frame_sync_offset: FrameSyncOffset,
+    pub frame_sync_polarity: FrameSyncPolarity,
+    pub frame_sync_active_level_length: word::U7,
+    pub frame_sync_definition: FrameSyncDefinition,
+    pub frame_length: u8,
+    pub clock_strobe: ClockStrobe,
+    pub output_drive: OutputDrive,
+    pub master_clock_divider: MasterClockDivider,
+    pub is_high_impedenane_on_inactive_slot: bool,
+    pub fifo_threshold: FifoThreshold,
+    pub companding: Companding,
+    pub complement_format: ComplementFormat,
+    pub mute_value: MuteValue,
+    pub mute_detection_counter: word::U5,
+}
+
+impl Default for Config {
+    fn default() -> Self {
+        Self {
+            mode: Mode::Master,
+            is_sync_output: false,
+            sync_enable: SyncEnable::Asynchronous,
+            protocol: Protocol::Free,
+            slot_size: SlotSize::DataSize,
+            slot_count: word::U4(2),
+            first_bit_offset: word::U5(0),
+            slot_enable: 0b11,
+            data_size: DataSize::Data16,
+            stereo_mono: StereoMono::Stereo,
+            bit_order: BitOrder::LsbFirst,
+            frame_sync_offset: FrameSyncOffset::BeforeFirstBit,
+            frame_sync_polarity: FrameSyncPolarity::ActiveLow,
+            frame_sync_active_level_length: word::U7(16),
+            frame_sync_definition: FrameSyncDefinition::ChannelIdentification,
+            frame_length: 32,
+            master_clock_divider: MasterClockDivider::MasterClockDisabled,
+            clock_strobe: ClockStrobe::Rising,
+            output_drive: OutputDrive::Immediately,
+            is_high_impedenane_on_inactive_slot: false,
+            fifo_threshold: FifoThreshold::ThreeQuarters,
+            companding: Companding::None,
+            complement_format: ComplementFormat::TwosComplement,
+            mute_value: MuteValue::Zero,
+            mute_detection_counter: word::U5(4),
+        }
+    }
+}
+
+impl Config {
+    pub fn new_i2s() -> Self {
+        return Default::default();
+    }
+
+    pub fn new_msb_first() -> Self {
+        Self {
+            bit_order: BitOrder::MsbFirst,
+            frame_sync_offset: FrameSyncOffset::OnFirstBit,
+            ..Default::default()
+        }
+    }
+}
+
+#[derive(Copy, Clone)]
+pub enum SubBlock {
+    A = 0,
+    B = 1,
+}
+
+enum RingBuffer<'d, C: Channel, W: word::Word> {
+    Writable(WritableRingBuffer<'d, C, W>),
+    Readable(ReadableRingBuffer<'d, C, W>),
+}
+
+#[cfg(any(sai_v1, sai_v2, sai_v3, sai_v4))]
+fn wdr<W: word::Word>(w: crate::pac::sai::Sai, sub_block: SubBlock) -> *mut W {
+    let ch = w.ch(sub_block as usize);
+    ch.dr().as_ptr() as _
+}
+
+pub struct Sai<'d, T: Instance, C: Channel, W: word::Word> {
+    _peri: PeripheralRef<'d, T>,
+    sd: Option<PeripheralRef<'d, AnyPin>>,
+    fs: Option<PeripheralRef<'d, AnyPin>>,
+    sck: Option<PeripheralRef<'d, AnyPin>>,
+    mclk: Option<PeripheralRef<'d, AnyPin>>,
+    ring_buffer: RingBuffer<'d, C, W>,
+    sub_block: SubBlock,
+}
+
+impl<'d, T: Instance, C: Channel, W: word::Word> Sai<'d, T, C, W> {
+    fn get_transmitter_af_types(mode: Mode) -> (AFType, AFType) {
+        match mode {
+            Mode::Master => (AFType::OutputPushPull, AFType::OutputPushPull),
+            Mode::Slave => (AFType::OutputPushPull, AFType::Input),
+        }
+    }
+
+    pub fn new_asynchronous_transmitter_with_mclk_a(
+        peri: impl Peripheral<P = T> + 'd,
+        sck: impl Peripheral<P = impl SckAPin<T>> + 'd,
+        sd: impl Peripheral<P = impl SdAPin<T>> + 'd,
+        fs: impl Peripheral<P = impl FsAPin<T>> + 'd,
+        mclk: impl Peripheral<P = impl MclkAPin<T>> + 'd,
+        dma: impl Peripheral<P = C> + 'd,
+        dma_buf: &'d mut [W],
+        mut config: Config,
+    ) -> Self
+    where
+        C: Channel + DmaA<T>,
+    {
+        into_ref!(mclk);
+
+        mclk.set_as_af(mclk.af_num(), AFType::OutputPushPull);
+        mclk.set_speed(crate::gpio::Speed::VeryHigh);
+
+        if config.master_clock_divider == MasterClockDivider::MasterClockDisabled {
+            config.master_clock_divider = MasterClockDivider::Div1;
+        }
+
+        Self::new_asynchronous_transmitter_a(peri, sck, sd, fs, dma, dma_buf, config)
+    }
+
+    pub fn new_asynchronous_transmitter_a(
+        peri: impl Peripheral<P = T> + 'd,
+        sck: impl Peripheral<P = impl SckAPin<T>> + 'd,
+        sd: impl Peripheral<P = impl SdAPin<T>> + 'd,
+        fs: impl Peripheral<P = impl FsAPin<T>> + 'd,
+        dma: impl Peripheral<P = C> + 'd,
+        dma_buf: &'d mut [W],
+        config: Config,
+    ) -> Self
+    where
+        C: Channel + DmaA<T>,
+    {
+        into_ref!(peri, dma, sck, sd, fs);
+
+        let (sd_af_type, ck_af_type) = Self::get_transmitter_af_types(config.mode);
+        sd.set_as_af(sd.af_num(), sd_af_type);
+        sd.set_speed(crate::gpio::Speed::VeryHigh);
+
+        sck.set_as_af(sck.af_num(), ck_af_type);
+        sck.set_speed(crate::gpio::Speed::VeryHigh);
+        fs.set_as_af(fs.af_num(), ck_af_type);
+        fs.set_speed(crate::gpio::Speed::VeryHigh);
+
+        let request = dma.request();
+        let opts = TransferOptions {
+            half_transfer_ir: true,
+            circular: true,
+            ..Default::default()
+        };
+
+        let sub_block = SubBlock::A;
+
+        Self::new_inner(
+            peri,
+            sub_block,
+            Some(sck.map_into()),
+            None,
+            Some(sd.map_into()),
+            Some(fs.map_into()),
+            RingBuffer::Writable(unsafe {
+                WritableRingBuffer::new_write(dma, request, wdr(T::REGS, sub_block), dma_buf, opts)
+            }),
+            config,
+        )
+    }
+
+    pub fn new_asynchronous_transmitter_with_mclk_b(
+        peri: impl Peripheral<P = T> + 'd,
+        sck: impl Peripheral<P = impl SckBPin<T>> + 'd,
+        sd: impl Peripheral<P = impl SdBPin<T>> + 'd,
+        fs: impl Peripheral<P = impl FsBPin<T>> + 'd,
+        mclk: impl Peripheral<P = impl MclkBPin<T>> + 'd,
+        dma: impl Peripheral<P = C> + 'd,
+        dma_buf: &'d mut [W],
+        mut config: Config,
+    ) -> Self
+    where
+        C: Channel + DmaB<T>,
+    {
+        into_ref!(mclk);
+
+        mclk.set_as_af(mclk.af_num(), AFType::OutputPushPull);
+        mclk.set_speed(crate::gpio::Speed::VeryHigh);
+
+        if config.master_clock_divider == MasterClockDivider::MasterClockDisabled {
+            config.master_clock_divider = MasterClockDivider::Div1;
+        }
+
+        Self::new_asynchronous_transmitter_b(peri, sck, sd, fs, dma, dma_buf, config)
+    }
+
+    pub fn new_asynchronous_transmitter_b(
+        peri: impl Peripheral<P = T> + 'd,
+        sck: impl Peripheral<P = impl SckBPin<T>> + 'd,
+        sd: impl Peripheral<P = impl SdBPin<T>> + 'd,
+        fs: impl Peripheral<P = impl FsBPin<T>> + 'd,
+        dma: impl Peripheral<P = C> + 'd,
+        dma_buf: &'d mut [W],
+        config: Config,
+    ) -> Self
+    where
+        C: Channel + DmaB<T>,
+    {
+        into_ref!(dma, peri, sck, sd, fs);
+
+        let (sd_af_type, ck_af_type) = Self::get_transmitter_af_types(config.mode);
+
+        sd.set_as_af(sd.af_num(), sd_af_type);
+        sd.set_speed(crate::gpio::Speed::VeryHigh);
+
+        sck.set_as_af(sck.af_num(), ck_af_type);
+        sck.set_speed(crate::gpio::Speed::VeryHigh);
+        fs.set_as_af(fs.af_num(), ck_af_type);
+        fs.set_speed(crate::gpio::Speed::VeryHigh);
+
+        let request = dma.request();
+        let opts = TransferOptions {
+            half_transfer_ir: true,
+            ..Default::default()
+        };
+
+        let sub_block = SubBlock::B;
+
+        Self::new_inner(
+            peri,
+            sub_block,
+            Some(sck.map_into()),
+            None,
+            Some(sd.map_into()),
+            Some(fs.map_into()),
+            RingBuffer::Writable(unsafe {
+                WritableRingBuffer::new_write(dma, request, wdr(T::REGS, sub_block), dma_buf, opts)
+            }),
+            config,
+        )
+    }
+
+    pub fn start(self: &mut Self) {
+        match self.ring_buffer {
+            RingBuffer::Writable(ref mut rb) => {
+                rb.start();
+            }
+            RingBuffer::Readable(ref mut rb) => {
+                rb.start();
+            }
+        }
+    }
+
+    fn is_transmitter(ring_buffer: &RingBuffer<C, W>) -> bool {
+        match ring_buffer {
+            RingBuffer::Writable(_) => true,
+            _ => false,
+        }
+    }
+
+    fn new_inner(
+        peri: impl Peripheral<P = T> + 'd,
+        sub_block: SubBlock,
+        sck: Option<PeripheralRef<'d, AnyPin>>,
+        mclk: Option<PeripheralRef<'d, AnyPin>>,
+        sd: Option<PeripheralRef<'d, AnyPin>>,
+        fs: Option<PeripheralRef<'d, AnyPin>>,
+        ring_buffer: RingBuffer<'d, C, W>,
+        config: Config,
+    ) -> Self {
+        T::enable();
+        T::reset();
+
+        #[cfg(any(sai_v4))]
+        {
+            /// Not totally clear from the datasheet if this is right
+            /// This is only used if using SyncEnable::External
+            let value: u8 = if T::REGS.as_ptr() == stm32_metapac::SAI1.as_ptr() {
+                1 //this is SAI1, so sync with SAI2
+            } else {
+                0 //this is SAI2, so sync with SAI1
+            };
+            T::REGS.gcr().modify(|w| {
+                w.set_syncin(value);
+            });
+
+            if config.is_sync_output {
+                let syncout: u8 = match sub_block {
+                    SubBlock::A => 0b01,
+                    SubBlock::B => 0b10,
+                };
+                T::REGS.gcr().modify(|w| {
+                    w.set_syncout(syncout);
+                });
+            }
+        }
+
+        #[cfg(any(sai_v1, sai_v2, sai_v3, sai_v4))]
+        {
+            let ch = T::REGS.ch(sub_block as usize);
+            ch.cr1().modify(|w| {
+                w.set_mode(config.mode.mode(if Self::is_transmitter(&ring_buffer) {
+                    TxRx::Transmiter
+                } else {
+                    TxRx::Receiver
+                }));
+                w.set_prtcfg(config.protocol.prtcfg());
+                w.set_ds(config.data_size.ds());
+                w.set_lsbfirst(config.bit_order.lsbfirst());
+                w.set_ckstr(config.clock_strobe.ckstr());
+                w.set_syncen(config.sync_enable.syncen());
+                w.set_mono(config.stereo_mono.mono());
+                w.set_outdriv(config.output_drive.outdriv());
+                w.set_mckdiv(config.master_clock_divider.mckdiv());
+                w.set_nodiv(
+                    if config.master_clock_divider == MasterClockDivider::MasterClockDisabled {
+                        vals::Nodiv::NODIV
+                    } else {
+                        vals::Nodiv::MASTERCLOCK
+                    },
+                );
+                w.set_dmaen(true);
+            });
+
+            ch.cr2().modify(|w| {
+                w.set_fth(config.fifo_threshold.fth());
+                w.set_comp(config.companding.comp());
+                w.set_cpl(config.complement_format.cpl());
+                w.set_muteval(config.mute_value.muteval());
+                w.set_mutecnt(config.mute_detection_counter.0 as u8);
+                w.set_tris(config.is_high_impedenane_on_inactive_slot);
+            });
+
+            ch.frcr().modify(|w| {
+                w.set_fsoff(config.frame_sync_offset.fsoff());
+                w.set_fspol(config.frame_sync_polarity.fspol());
+                w.set_fsdef(config.frame_sync_definition.fsdef());
+                w.set_fsall(config.frame_sync_active_level_length.0 as u8);
+                w.set_frl(config.frame_length - 1);
+            });
+
+            ch.slotr().modify(|w| {
+                w.set_nbslot(config.slot_count.0 as u8 - 1);
+                w.set_slotsz(config.slot_size.slotsz());
+                w.set_fboff(config.first_bit_offset.0 as u8);
+                w.set_sloten(vals::Sloten(config.slot_enable as u16));
+            });
+
+            ch.cr1().modify(|w| w.set_saien(true));
+        }
+
+        Self {
+            _peri: peri.into_ref(),
+            sub_block,
+            sck,
+            mclk,
+            sd,
+            fs,
+            ring_buffer,
+        }
+    }
+
+    fn flush(&mut self) {
+        let ch = T::REGS.ch(self.sub_block as usize);
+        ch.cr1().modify(|w| w.set_saien(false));
+        #[cfg(any(sai_v1, sai_v2))]
+        {
+            ch.cr2().modify(|w| w.set_fflush(vals::Fflush::FLUSH));
+        }
+        #[cfg(any(sai_v3, sai_v4))]
+        {
+            ch.cr2().modify(|w| w.set_fflush(true));
+        }
+        ch.cr1().modify(|w| w.set_saien(true));
+    }
+
+    fn set_mute(&mut self, value: bool) {
+        let ch = T::REGS.ch(self.sub_block as usize);
+        ch.cr2().modify(|w| w.set_mute(value));
+    }
+
+    /// Reconfigures it with the supplied config.
+    pub fn reconfigure(&mut self, config: Config) {}
+
+    pub fn get_current_config(&self) -> Config {
+        Config::default()
+    }
+
+    pub async fn write(&mut self, data: &[W]) -> Result<(), Error> {
+        match &mut self.ring_buffer {
+            RingBuffer::Writable(buffer) => {
+                buffer.write_exact(data).await;
+                Ok(())
+            }
+            _ => return Err(Error::NotATransmitter),
+        }
+    }
+
+    pub async fn read(&mut self, data: &mut [W]) -> Result<(), Error> {
+        match &mut self.ring_buffer {
+            RingBuffer::Readable(buffer) => {
+                buffer.read_exact(data).await;
+                Ok(())
+            }
+            _ => Err(Error::NotAReceiver),
+        }
+    }
+}
+
+impl<'d, T: Instance, C: Channel, W: word::Word> Drop for Sai<'d, T, C, W> {
+    fn drop(&mut self) {
+        let ch = T::REGS.ch(self.sub_block as usize);
+        ch.cr1().modify(|w| w.set_saien(false));
+        self.fs.as_ref().map(|x| x.set_as_disconnected());
+        self.sd.as_ref().map(|x| x.set_as_disconnected());
+        self.sck.as_ref().map(|x| x.set_as_disconnected());
+        self.mclk.as_ref().map(|x| x.set_as_disconnected());
+    }
+}
+
+pub(crate) mod sealed {
+    use super::*;
+
+    pub trait Instance {
+        const REGS: Regs;
+    }
+}
+
+pub trait Word: word::Word {}
+
+pub trait Instance: Peripheral<P = Self> + sealed::Instance + RccPeripheral {}
+pin_trait!(SckAPin, Instance);
+pin_trait!(SckBPin, Instance);
+pin_trait!(FsAPin, Instance);
+pin_trait!(FsBPin, Instance);
+pin_trait!(SdAPin, Instance);
+pin_trait!(SdBPin, Instance);
+pin_trait!(MclkAPin, Instance);
+pin_trait!(MclkBPin, Instance);
+
+dma_trait!(DmaA, Instance);
+dma_trait!(DmaB, Instance);
+
+foreach_peripheral!(
+    (sai, $inst:ident) => {
+        impl sealed::Instance for peripherals::$inst {
+            const REGS: Regs = crate::pac::$inst;
+        }
+
+        impl Instance for peripherals::$inst {}
+    };
+);
+
+impl<'d, T: Instance, C: Channel, W: word::Word> SetConfig for Sai<'d, T, C, W> {
+    type Config = Config;
+    fn set_config(&mut self, config: &Self::Config) {
+        self.reconfigure(*config);
+    }
+}